linux/lib/vsprintf.c

2574 lines
60 KiB

vsprintf: check real user/group id for %pK Some setuid binaries will allow reading of files which have read permission by the real user id. This is problematic with files which use %pK because the file access permission is checked at open() time, but the kptr_restrict setting is checked at read() time. If a setuid binary opens a %pK file as an unprivileged user, and then elevates permissions before reading the file, then kernel pointer values may be leaked. This happens for example with the setuid pppd application on Ubuntu 12.04: $ head -1 /proc/kallsyms 00000000 T startup_32 $ pppd file /proc/kallsyms pppd: In file /proc/kallsyms: unrecognized option 'c1000000' This will only leak the pointer value from the first line, but other setuid binaries may leak more information. Fix this by adding a check that in addition to the current process having CAP_SYSLOG, that effective user and group ids are equal to the real ids. If a setuid binary reads the contents of a file which uses %pK then the pointer values will be printed as NULL if the real user is unprivileged. Update the sysctl documentation to reflect the changes, and also correct the documentation to state the kptr_restrict=0 is the default. This is a only temporary solution to the issue. The correct solution is to do the permission check at open() time on files, and to replace %pK with a function which checks the open() time permission. %pK uses in printk should be removed since no sane permission check can be done, and instead protected by using dmesg_restrict. Signed-off-by: Ryan Mallon <rmallon@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Joe Perches <joe@perches.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-12 15:08:51 -08:00
vsprintf.c: optimizing, part 2: base 10 conversion speedup, v2 Optimize integer-to-string conversion in vsprintf.c for base 10. This is by far the most used conversion, and in some use cases it impacts performance. For example, top reads /proc/$PID/stat for every process, and with 4000 processes decimal conversion alone takes noticeable time. Using code from http://www.cs.uiowa.edu/~jones/bcd/decimal.html (with permission from the author, Douglas W. Jones) binary-to-decimal-string conversion is done in groups of five digits at once, using only additions/subtractions/shifts (with -O2; -Os throws in some multiply instructions). On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code. This patch is run tested. Userspace benchmark/test is also attached. I tested it on PIII and AMD64 and new code is generally ~2.5 times faster. On AMD64: # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 12895992590592 ok... [Ctrl-C] # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 26025406464 ok... [Ctrl-C] More realistic test: top from busybox project was modified to report how many us it took to scan /proc (this does not account any processing done after that, like sorting process list), and then I test it with 4000 processes: #!/bin/sh i=4000 while test $i != 0; do sleep 30 & let i-- done busybox top -b -n3 >/dev/null on unpatched kernel: top: 4120 processes took 102864 microseconds to scan top: 4120 processes took 91757 microseconds to scan top: 4120 processes took 92517 microseconds to scan top: 4120 processes took 92581 microseconds to scan on patched kernel: top: 4120 processes took 75460 microseconds to scan top: 4120 processes took 66451 microseconds to scan top: 4120 processes took 67267 microseconds to scan top: 4120 processes took 67618 microseconds to scan The speedup comes from much faster generation of /proc/PID/stat by sprintf() calls inside the kernel. Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:41:56 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf.c: optimizing, part 2: base 10 conversion speedup, v2 Optimize integer-to-string conversion in vsprintf.c for base 10. This is by far the most used conversion, and in some use cases it impacts performance. For example, top reads /proc/$PID/stat for every process, and with 4000 processes decimal conversion alone takes noticeable time. Using code from http://www.cs.uiowa.edu/~jones/bcd/decimal.html (with permission from the author, Douglas W. Jones) binary-to-decimal-string conversion is done in groups of five digits at once, using only additions/subtractions/shifts (with -O2; -Os throws in some multiply instructions). On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code. This patch is run tested. Userspace benchmark/test is also attached. I tested it on PIII and AMD64 and new code is generally ~2.5 times faster. On AMD64: # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 12895992590592 ok... [Ctrl-C] # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 26025406464 ok... [Ctrl-C] More realistic test: top from busybox project was modified to report how many us it took to scan /proc (this does not account any processing done after that, like sorting process list), and then I test it with 4000 processes: #!/bin/sh i=4000 while test $i != 0; do sleep 30 & let i-- done busybox top -b -n3 >/dev/null on unpatched kernel: top: 4120 processes took 102864 microseconds to scan top: 4120 processes took 91757 microseconds to scan top: 4120 processes took 92517 microseconds to scan top: 4120 processes took 92581 microseconds to scan on patched kernel: top: 4120 processes took 75460 microseconds to scan top: 4120 processes took 66451 microseconds to scan top: 4120 processes took 67267 microseconds to scan top: 4120 processes took 67618 microseconds to scan The speedup comes from much faster generation of /proc/PID/stat by sprintf() calls inside the kernel. Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:41:56 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf.c: optimizing, part 2: base 10 conversion speedup, v2 Optimize integer-to-string conversion in vsprintf.c for base 10. This is by far the most used conversion, and in some use cases it impacts performance. For example, top reads /proc/$PID/stat for every process, and with 4000 processes decimal conversion alone takes noticeable time. Using code from http://www.cs.uiowa.edu/~jones/bcd/decimal.html (with permission from the author, Douglas W. Jones) binary-to-decimal-string conversion is done in groups of five digits at once, using only additions/subtractions/shifts (with -O2; -Os throws in some multiply instructions). On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code. This patch is run tested. Userspace benchmark/test is also attached. I tested it on PIII and AMD64 and new code is generally ~2.5 times faster. On AMD64: # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 12895992590592 ok... [Ctrl-C] # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 26025406464 ok... [Ctrl-C] More realistic test: top from busybox project was modified to report how many us it took to scan /proc (this does not account any processing done after that, like sorting process list), and then I test it with 4000 processes: #!/bin/sh i=4000 while test $i != 0; do sleep 30 & let i-- done busybox top -b -n3 >/dev/null on unpatched kernel: top: 4120 processes took 102864 microseconds to scan top: 4120 processes took 91757 microseconds to scan top: 4120 processes took 92517 microseconds to scan top: 4120 processes took 92581 microseconds to scan on patched kernel: top: 4120 processes took 75460 microseconds to scan top: 4120 processes took 66451 microseconds to scan top: 4120 processes took 67267 microseconds to scan top: 4120 processes took 67618 microseconds to scan The speedup comes from much faster generation of /proc/PID/stat by sprintf() calls inside the kernel. Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:41:56 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf.c: optimizing, part 2: base 10 conversion speedup, v2 Optimize integer-to-string conversion in vsprintf.c for base 10. This is by far the most used conversion, and in some use cases it impacts performance. For example, top reads /proc/$PID/stat for every process, and with 4000 processes decimal conversion alone takes noticeable time. Using code from http://www.cs.uiowa.edu/~jones/bcd/decimal.html (with permission from the author, Douglas W. Jones) binary-to-decimal-string conversion is done in groups of five digits at once, using only additions/subtractions/shifts (with -O2; -Os throws in some multiply instructions). On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code. This patch is run tested. Userspace benchmark/test is also attached. I tested it on PIII and AMD64 and new code is generally ~2.5 times faster. On AMD64: # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 12895992590592 ok... [Ctrl-C] # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 26025406464 ok... [Ctrl-C] More realistic test: top from busybox project was modified to report how many us it took to scan /proc (this does not account any processing done after that, like sorting process list), and then I test it with 4000 processes: #!/bin/sh i=4000 while test $i != 0; do sleep 30 & let i-- done busybox top -b -n3 >/dev/null on unpatched kernel: top: 4120 processes took 102864 microseconds to scan top: 4120 processes took 91757 microseconds to scan top: 4120 processes took 92517 microseconds to scan top: 4120 processes took 92581 microseconds to scan on patched kernel: top: 4120 processes took 75460 microseconds to scan top: 4120 processes took 66451 microseconds to scan top: 4120 processes took 67267 microseconds to scan top: 4120 processes took 67618 microseconds to scan The speedup comes from much faster generation of /proc/PID/stat by sprintf() calls inside the kernel. Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:41:56 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf.c: optimizing, part 2: base 10 conversion speedup, v2 Optimize integer-to-string conversion in vsprintf.c for base 10. This is by far the most used conversion, and in some use cases it impacts performance. For example, top reads /proc/$PID/stat for every process, and with 4000 processes decimal conversion alone takes noticeable time. Using code from http://www.cs.uiowa.edu/~jones/bcd/decimal.html (with permission from the author, Douglas W. Jones) binary-to-decimal-string conversion is done in groups of five digits at once, using only additions/subtractions/shifts (with -O2; -Os throws in some multiply instructions). On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code. This patch is run tested. Userspace benchmark/test is also attached. I tested it on PIII and AMD64 and new code is generally ~2.5 times faster. On AMD64: # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 12895992590592 ok... [Ctrl-C] # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 26025406464 ok... [Ctrl-C] More realistic test: top from busybox project was modified to report how many us it took to scan /proc (this does not account any processing done after that, like sorting process list), and then I test it with 4000 processes: #!/bin/sh i=4000 while test $i != 0; do sleep 30 & let i-- done busybox top -b -n3 >/dev/null on unpatched kernel: top: 4120 processes took 102864 microseconds to scan top: 4120 processes took 91757 microseconds to scan top: 4120 processes took 92517 microseconds to scan top: 4120 processes took 92581 microseconds to scan on patched kernel: top: 4120 processes took 75460 microseconds to scan top: 4120 processes took 66451 microseconds to scan top: 4120 processes took 67267 microseconds to scan top: 4120 processes took 67618 microseconds to scan The speedup comes from much faster generation of /proc/PID/stat by sprintf() calls inside the kernel. Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:41:56 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf.c: optimizing, part 2: base 10 conversion speedup, v2 Optimize integer-to-string conversion in vsprintf.c for base 10. This is by far the most used conversion, and in some use cases it impacts performance. For example, top reads /proc/$PID/stat for every process, and with 4000 processes decimal conversion alone takes noticeable time. Using code from http://www.cs.uiowa.edu/~jones/bcd/decimal.html (with permission from the author, Douglas W. Jones) binary-to-decimal-string conversion is done in groups of five digits at once, using only additions/subtractions/shifts (with -O2; -Os throws in some multiply instructions). On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code. This patch is run tested. Userspace benchmark/test is also attached. I tested it on PIII and AMD64 and new code is generally ~2.5 times faster. On AMD64: # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 12895992590592 ok... [Ctrl-C] # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 26025406464 ok... [Ctrl-C] More realistic test: top from busybox project was modified to report how many us it took to scan /proc (this does not account any processing done after that, like sorting process list), and then I test it with 4000 processes: #!/bin/sh i=4000 while test $i != 0; do sleep 30 & let i-- done busybox top -b -n3 >/dev/null on unpatched kernel: top: 4120 processes took 102864 microseconds to scan top: 4120 processes took 91757 microseconds to scan top: 4120 processes took 92517 microseconds to scan top: 4120 processes took 92581 microseconds to scan on patched kernel: top: 4120 processes took 75460 microseconds to scan top: 4120 processes took 66451 microseconds to scan top: 4120 processes took 67267 microseconds to scan top: 4120 processes took 67618 microseconds to scan The speedup comes from much faster generation of /proc/PID/stat by sprintf() calls inside the kernel. Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:41:56 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf.c: optimizing, part 2: base 10 conversion speedup, v2 Optimize integer-to-string conversion in vsprintf.c for base 10. This is by far the most used conversion, and in some use cases it impacts performance. For example, top reads /proc/$PID/stat for every process, and with 4000 processes decimal conversion alone takes noticeable time. Using code from http://www.cs.uiowa.edu/~jones/bcd/decimal.html (with permission from the author, Douglas W. Jones) binary-to-decimal-string conversion is done in groups of five digits at once, using only additions/subtractions/shifts (with -O2; -Os throws in some multiply instructions). On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code. This patch is run tested. Userspace benchmark/test is also attached. I tested it on PIII and AMD64 and new code is generally ~2.5 times faster. On AMD64: # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 12895992590592 ok... [Ctrl-C] # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 26025406464 ok... [Ctrl-C] More realistic test: top from busybox project was modified to report how many us it took to scan /proc (this does not account any processing done after that, like sorting process list), and then I test it with 4000 processes: #!/bin/sh i=4000 while test $i != 0; do sleep 30 & let i-- done busybox top -b -n3 >/dev/null on unpatched kernel: top: 4120 processes took 102864 microseconds to scan top: 4120 processes took 91757 microseconds to scan top: 4120 processes took 92517 microseconds to scan top: 4120 processes took 92581 microseconds to scan on patched kernel: top: 4120 processes took 75460 microseconds to scan top: 4120 processes took 66451 microseconds to scan top: 4120 processes took 67267 microseconds to scan top: 4120 processes took 67618 microseconds to scan The speedup comes from much faster generation of /proc/PID/stat by sprintf() calls inside the kernel. Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:41:56 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf.c: optimizing, part 2: base 10 conversion speedup, v2 Optimize integer-to-string conversion in vsprintf.c for base 10. This is by far the most used conversion, and in some use cases it impacts performance. For example, top reads /proc/$PID/stat for every process, and with 4000 processes decimal conversion alone takes noticeable time. Using code from http://www.cs.uiowa.edu/~jones/bcd/decimal.html (with permission from the author, Douglas W. Jones) binary-to-decimal-string conversion is done in groups of five digits at once, using only additions/subtractions/shifts (with -O2; -Os throws in some multiply instructions). On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code. This patch is run tested. Userspace benchmark/test is also attached. I tested it on PIII and AMD64 and new code is generally ~2.5 times faster. On AMD64: # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 12895992590592 ok... [Ctrl-C] # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 26025406464 ok... [Ctrl-C] More realistic test: top from busybox project was modified to report how many us it took to scan /proc (this does not account any processing done after that, like sorting process list), and then I test it with 4000 processes: #!/bin/sh i=4000 while test $i != 0; do sleep 30 & let i-- done busybox top -b -n3 >/dev/null on unpatched kernel: top: 4120 processes took 102864 microseconds to scan top: 4120 processes took 91757 microseconds to scan top: 4120 processes took 92517 microseconds to scan top: 4120 processes took 92581 microseconds to scan on patched kernel: top: 4120 processes took 75460 microseconds to scan top: 4120 processes took 66451 microseconds to scan top: 4120 processes took 67267 microseconds to scan top: 4120 processes took 67618 microseconds to scan The speedup comes from much faster generation of /proc/PID/stat by sprintf() calls inside the kernel. Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:41:56 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf.c: optimizing, part 2: base 10 conversion speedup, v2 Optimize integer-to-string conversion in vsprintf.c for base 10. This is by far the most used conversion, and in some use cases it impacts performance. For example, top reads /proc/$PID/stat for every process, and with 4000 processes decimal conversion alone takes noticeable time. Using code from http://www.cs.uiowa.edu/~jones/bcd/decimal.html (with permission from the author, Douglas W. Jones) binary-to-decimal-string conversion is done in groups of five digits at once, using only additions/subtractions/shifts (with -O2; -Os throws in some multiply instructions). On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code. This patch is run tested. Userspace benchmark/test is also attached. I tested it on PIII and AMD64 and new code is generally ~2.5 times faster. On AMD64: # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 12895992590592 ok... [Ctrl-C] # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 26025406464 ok... [Ctrl-C] More realistic test: top from busybox project was modified to report how many us it took to scan /proc (this does not account any processing done after that, like sorting process list), and then I test it with 4000 processes: #!/bin/sh i=4000 while test $i != 0; do sleep 30 & let i-- done busybox top -b -n3 >/dev/null on unpatched kernel: top: 4120 processes took 102864 microseconds to scan top: 4120 processes took 91757 microseconds to scan top: 4120 processes took 92517 microseconds to scan top: 4120 processes took 92581 microseconds to scan on patched kernel: top: 4120 processes took 75460 microseconds to scan top: 4120 processes took 66451 microseconds to scan top: 4120 processes took 67267 microseconds to scan top: 4120 processes took 67618 microseconds to scan The speedup comes from much faster generation of /proc/PID/stat by sprintf() calls inside the kernel. Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:41:56 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
procfs: add num_to_str() to speed up /proc/stat == stat_check.py num = 0 with open("/proc/stat") as f: while num < 1000 : data = f.read() f.seek(0, 0) num = num + 1 == perf shows 20.39% stat_check.py [kernel.kallsyms] [k] format_decode 13.41% stat_check.py [kernel.kallsyms] [k] number 12.61% stat_check.py [kernel.kallsyms] [k] vsnprintf 10.85% stat_check.py [kernel.kallsyms] [k] memcpy 4.85% stat_check.py [kernel.kallsyms] [k] radix_tree_lookup 4.43% stat_check.py [kernel.kallsyms] [k] seq_printf This patch removes most of calls to vsnprintf() by adding num_to_str() and seq_print_decimal_ull(), which prints decimal numbers without rich functions provided by printf(). On my 8cpu box. == Before patch == [root@bluextal test]# time ./stat_check.py real 0m0.150s user 0m0.026s sys 0m0.121s == After patch == [root@bluextal test]# time ./stat_check.py real 0m0.055s user 0m0.022s sys 0m0.030s [akpm@linux-foundation.org: remove incorrect comment, use less statck in num_to_str(), move comment from .h to .c, simplify seq_put_decimal_ull()] [andrea@betterlinux.com: avoid breaking the ABI in /proc/stat] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrea Righi <andrea@betterlinux.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Turner <pjt@google.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-23 15:02:54 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
procfs: add num_to_str() to speed up /proc/stat == stat_check.py num = 0 with open("/proc/stat") as f: while num < 1000 : data = f.read() f.seek(0, 0) num = num + 1 == perf shows 20.39% stat_check.py [kernel.kallsyms] [k] format_decode 13.41% stat_check.py [kernel.kallsyms] [k] number 12.61% stat_check.py [kernel.kallsyms] [k] vsnprintf 10.85% stat_check.py [kernel.kallsyms] [k] memcpy 4.85% stat_check.py [kernel.kallsyms] [k] radix_tree_lookup 4.43% stat_check.py [kernel.kallsyms] [k] seq_printf This patch removes most of calls to vsnprintf() by adding num_to_str() and seq_print_decimal_ull(), which prints decimal numbers without rich functions provided by printf(). On my 8cpu box. == Before patch == [root@bluextal test]# time ./stat_check.py real 0m0.150s user 0m0.026s sys 0m0.121s == After patch == [root@bluextal test]# time ./stat_check.py real 0m0.055s user 0m0.022s sys 0m0.030s [akpm@linux-foundation.org: remove incorrect comment, use less statck in num_to_str(), move comment from .h to .c, simplify seq_put_decimal_ull()] [andrea@betterlinux.com: avoid breaking the ABI in /proc/stat] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrea Righi <andrea@betterlinux.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Turner <pjt@google.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-23 15:02:54 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
procfs: add num_to_str() to speed up /proc/stat == stat_check.py num = 0 with open("/proc/stat") as f: while num < 1000 : data = f.read() f.seek(0, 0) num = num + 1 == perf shows 20.39% stat_check.py [kernel.kallsyms] [k] format_decode 13.41% stat_check.py [kernel.kallsyms] [k] number 12.61% stat_check.py [kernel.kallsyms] [k] vsnprintf 10.85% stat_check.py [kernel.kallsyms] [k] memcpy 4.85% stat_check.py [kernel.kallsyms] [k] radix_tree_lookup 4.43% stat_check.py [kernel.kallsyms] [k] seq_printf This patch removes most of calls to vsnprintf() by adding num_to_str() and seq_print_decimal_ull(), which prints decimal numbers without rich functions provided by printf(). On my 8cpu box. == Before patch == [root@bluextal test]# time ./stat_check.py real 0m0.150s user 0m0.026s sys 0m0.121s == After patch == [root@bluextal test]# time ./stat_check.py real 0m0.055s user 0m0.022s sys 0m0.030s [akpm@linux-foundation.org: remove incorrect comment, use less statck in num_to_str(), move comment from .h to .c, simplify seq_put_decimal_ull()] [andrea@betterlinux.com: avoid breaking the ABI in /proc/stat] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrea Righi <andrea@betterlinux.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Turner <pjt@google.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-23 15:02:54 -07:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
procfs: add num_to_str() to speed up /proc/stat == stat_check.py num = 0 with open("/proc/stat") as f: while num < 1000 : data = f.read() f.seek(0, 0) num = num + 1 == perf shows 20.39% stat_check.py [kernel.kallsyms] [k] format_decode 13.41% stat_check.py [kernel.kallsyms] [k] number 12.61% stat_check.py [kernel.kallsyms] [k] vsnprintf 10.85% stat_check.py [kernel.kallsyms] [k] memcpy 4.85% stat_check.py [kernel.kallsyms] [k] radix_tree_lookup 4.43% stat_check.py [kernel.kallsyms] [k] seq_printf This patch removes most of calls to vsnprintf() by adding num_to_str() and seq_print_decimal_ull(), which prints decimal numbers without rich functions provided by printf(). On my 8cpu box. == Before patch == [root@bluextal test]# time ./stat_check.py real 0m0.150s user 0m0.026s sys 0m0.121s == After patch == [root@bluextal test]# time ./stat_check.py real 0m0.055s user 0m0.022s sys 0m0.030s [akpm@linux-foundation.org: remove incorrect comment, use less statck in num_to_str(), move comment from .h to .c, simplify seq_put_decimal_ull()] [andrea@betterlinux.com: avoid breaking the ABI in /proc/stat] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrea Righi <andrea@betterlinux.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Turner <pjt@google.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-23 15:02:54 -07:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf.c: optimizing, part 2: base 10 conversion speedup, v2 Optimize integer-to-string conversion in vsprintf.c for base 10. This is by far the most used conversion, and in some use cases it impacts performance. For example, top reads /proc/$PID/stat for every process, and with 4000 processes decimal conversion alone takes noticeable time. Using code from http://www.cs.uiowa.edu/~jones/bcd/decimal.html (with permission from the author, Douglas W. Jones) binary-to-decimal-string conversion is done in groups of five digits at once, using only additions/subtractions/shifts (with -O2; -Os throws in some multiply instructions). On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code. This patch is run tested. Userspace benchmark/test is also attached. I tested it on PIII and AMD64 and new code is generally ~2.5 times faster. On AMD64: # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 12895992590592 ok... [Ctrl-C] # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 26025406464 ok... [Ctrl-C] More realistic test: top from busybox project was modified to report how many us it took to scan /proc (this does not account any processing done after that, like sorting process list), and then I test it with 4000 processes: #!/bin/sh i=4000 while test $i != 0; do sleep 30 & let i-- done busybox top -b -n3 >/dev/null on unpatched kernel: top: 4120 processes took 102864 microseconds to scan top: 4120 processes took 91757 microseconds to scan top: 4120 processes took 92517 microseconds to scan top: 4120 processes took 92581 microseconds to scan on patched kernel: top: 4120 processes took 75460 microseconds to scan top: 4120 processes took 66451 microseconds to scan top: 4120 processes took 67267 microseconds to scan top: 4120 processes took 67618 microseconds to scan The speedup comes from much faster generation of /proc/PID/stat by sprintf() calls inside the kernel. Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:41:56 -07:00
vsprintf.c: optimizing, part 2: base 10 conversion speedup, v2 Optimize integer-to-string conversion in vsprintf.c for base 10. This is by far the most used conversion, and in some use cases it impacts performance. For example, top reads /proc/$PID/stat for every process, and with 4000 processes decimal conversion alone takes noticeable time. Using code from http://www.cs.uiowa.edu/~jones/bcd/decimal.html (with permission from the author, Douglas W. Jones) binary-to-decimal-string conversion is done in groups of five digits at once, using only additions/subtractions/shifts (with -O2; -Os throws in some multiply instructions). On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code. This patch is run tested. Userspace benchmark/test is also attached. I tested it on PIII and AMD64 and new code is generally ~2.5 times faster. On AMD64: # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 12895992590592 ok... [Ctrl-C] # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 26025406464 ok... [Ctrl-C] More realistic test: top from busybox project was modified to report how many us it took to scan /proc (this does not account any processing done after that, like sorting process list), and then I test it with 4000 processes: #!/bin/sh i=4000 while test $i != 0; do sleep 30 & let i-- done busybox top -b -n3 >/dev/null on unpatched kernel: top: 4120 processes took 102864 microseconds to scan top: 4120 processes took 91757 microseconds to scan top: 4120 processes took 92517 microseconds to scan top: 4120 processes took 92581 microseconds to scan on patched kernel: top: 4120 processes took 75460 microseconds to scan top: 4120 processes took 66451 microseconds to scan top: 4120 processes took 67267 microseconds to scan top: 4120 processes took 67618 microseconds to scan The speedup comes from much faster generation of /proc/PID/stat by sprintf() calls inside the kernel. Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:41:56 -07:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf.c: optimizing, part 2: base 10 conversion speedup, v2 Optimize integer-to-string conversion in vsprintf.c for base 10. This is by far the most used conversion, and in some use cases it impacts performance. For example, top reads /proc/$PID/stat for every process, and with 4000 processes decimal conversion alone takes noticeable time. Using code from http://www.cs.uiowa.edu/~jones/bcd/decimal.html (with permission from the author, Douglas W. Jones) binary-to-decimal-string conversion is done in groups of five digits at once, using only additions/subtractions/shifts (with -O2; -Os throws in some multiply instructions). On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code. This patch is run tested. Userspace benchmark/test is also attached. I tested it on PIII and AMD64 and new code is generally ~2.5 times faster. On AMD64: # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 12895992590592 ok... [Ctrl-C] # ./vsprintf_verify-O2 Original decimal conv: .......... 151 ns per iteration Patched decimal conv: .......... 62 ns per iteration Testing correctness 26025406464 ok... [Ctrl-C] More realistic test: top from busybox project was modified to report how many us it took to scan /proc (this does not account any processing done after that, like sorting process list), and then I test it with 4000 processes: #!/bin/sh i=4000 while test $i != 0; do sleep 30 & let i-- done busybox top -b -n3 >/dev/null on unpatched kernel: top: 4120 processes took 102864 microseconds to scan top: 4120 processes took 91757 microseconds to scan top: 4120 processes took 92517 microseconds to scan top: 4120 processes took 92581 microseconds to scan on patched kernel: top: 4120 processes took 75460 microseconds to scan top: 4120 processes took 66451 microseconds to scan top: 4120 processes took 67267 microseconds to scan top: 4120 processes took 67618 microseconds to scan The speedup comes from much faster generation of /proc/PID/stat by sprintf() calls inside the kernel. Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:41:56 -07:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: introduce %pf format specifier A printf format specifier which would allow us to print a pure function name has been suggested by Andrew Morton a couple of months ago. The current %pF is very convenient to print a function symbol, but often we only want to print the name of the function, without its asm offset. That's what %pf does in this patch. The lowecase f has been chosen for its intuitive meaning of a 'weak kind of %pF'. The support for this new format would be welcome by the tracing code where the need to print pure function names is often needed. This is also true for other parts of the kernel: $ git-grep -E "kallsyms_lookup\(.+?\)" arch/blackfin/kernel/traps.c: symname = kallsyms_lookup(address, &symsize, &offset, &modname, namebuf); arch/powerpc/xmon/xmon.c: name = kallsyms_lookup(pc, &size, &offset, NULL, tmpstr); arch/sh/kernel/cpu/sh5/unwind.c: sym = kallsyms_lookup(pc, NULL, &offset, NULL, namebuf); arch/x86/kernel/ftrace.c: kallsyms_lookup((unsigned long) syscall, NULL, NULL, NULL, str); kernel/kprobes.c: sym = kallsyms_lookup((unsigned long)p->addr, NULL, kernel/lockdep.c: return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup((unsigned long)rec->ops->func, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, &modname, str); kernel/trace/ftrace.c: kallsyms_lookup(*ptr, NULL, NULL, NULL, str); kernel/trace/trace_functions.c: kallsyms_lookup(ip, NULL, NULL, NULL, str); kernel/trace/trace_output.c: kallsyms_lookup(address, NULL, NULL, NULL, str); Changes in v2: - Add the explanation of the %pf role for vsnprintf() and bstr_printf() - Change the comments by dropping the "asm offset" notion and only define the %pf against the actual function offset notion. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Zhaolei <zhaolei@cn.fujitsu.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20090415154817.GC5989@nowhere> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-15 17:48:18 +02:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: further optimize decimal conversion Previous code was using optimizations which were developed to work well even on narrow-word CPUs (by today's standards). But Linux runs only on 32-bit and wider CPUs. We can use that. First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly divide by 10 much larger numbers, and thus we can print groups of 9 digits instead of groups of 5 digits. Next: there are two algorithms to print larger numbers. One is generic: divide by 1000000000 and repeatedly print groups of (up to) 9 digits. It's conceptually simple, but requires an (unsigned long long) / 1000000000 division. Second algorithm splits 64-bit unsigned long long into 16-bit chunks, manipulates them cleverly and generates groups of 4 decimal digits. It so happens that it does NOT require long long division. If long is > 32 bits, division of 64-bit values is relatively easy, and we will use the first algorithm. If long long is > 64 bits (strange architecture with VERY large long long), second algorithm can't be used, and we again use the first one. Else (if long is 32 bits and long long is 64 bits) we use second one. And third: there is a simple optimization which takes fast path not only for zero as was done before, but for all one-digit numbers. In all tested cases new code is faster than old one, in many cases by 30%, in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit case. This patch is based upon an original from Michal Nazarewicz. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 16:26:08 -07:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
lib: vsprintf: add IPv4/v6 generic %p[Ii]S[pfs] format specifier In order to avoid making code that deals with printing both, IPv4 and IPv6 addresses, unnecessary complicated as for example ... if (sa.sa_family == AF_INET6) printk("... %pI6 ...", ..sin6_addr); else printk("... %pI4 ...", ..sin_addr.s_addr); ... it would be better to introduce a format specifier that can deal with those kind of situations internally; just as we have a "struct sockaddr" for generic mapping into "struct sockaddr_in" or "struct sockaddr_in6" as e.g. done in "union sctp_addr". Then, we could reduce the above statement into something like: printk("... %pIS ..", &sockaddr); In case our pointer is NULL, pointer() then deals with that already at an earlier point in time internally. While we're at it, support for both %piS/%pIS, where 'S' stands for sockaddr, comes (almost) for free. Additionally to that, postfix specifiers 'p', 'f' and 's' are supported as suggested and initially implemented in 2009 by Joe Perches [1]. Handling of those additional specifiers orientate on the initial RFC that was proposed. Also we support IPv6 compressed format specified by 'c' and various other IPv4 extensions as stated in the documentation part. Likely, there are many other areas than just SCTP in the kernel to make use of this extension as well. [1] http://patchwork.ozlabs.org/patch/31480/ Signed-off-by: Daniel Borkmann <dborkman@redhat.com> CC: Joe Perches <joe@perches.com> CC: linux-kernel@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-28 19:49:39 +02:00
kptr_restrict for hiding kernel pointers from unprivileged users Add the %pK printk format specifier and the /proc/sys/kernel/kptr_restrict sysctl. The %pK format specifier is designed to hide exposed kernel pointers, specifically via /proc interfaces. Exposing these pointers provides an easy target for kernel write vulnerabilities, since they reveal the locations of writable structures containing easily triggerable function pointers. The behavior of %pK depends on the kptr_restrict sysctl. If kptr_restrict is set to 0, no deviation from the standard %p behavior occurs. If kptr_restrict is set to 1, the default, if the current user (intended to be a reader via seq_printf(), etc.) does not have CAP_SYSLOG (currently in the LSM tree), kernel pointers using %pK are printed as 0's. If kptr_restrict is set to 2, kernel pointers using %pK are printed as 0's regardless of privileges. Replacing with 0's was chosen over the default "(null)", which cannot be parsed by userland %p, which expects "(nil)". [akpm@linux-foundation.org: check for IRQ context when !kptr_restrict, save an indent level, s/WARN/WARN_ONCE/] [akpm@linux-foundation.org: coding-style fixup] [randy.dunlap@oracle.com: fix kernel/sysctl.c warning] Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: James Morris <jmorris@namei.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Thomas Graf <tgraf@infradead.org> Cc: Eugene Teo <eugeneteo@kernel.org> Cc: Kees Cook <kees.cook@canonical.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David S. Miller <davem@davemloft.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Eric Paris <eparis@parisplace.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-12 16:59:41 -08:00
vsprintf: introduce %pf format specifier A printf format specifier which would allow us to print a pure function name has been suggested by Andrew Morton a couple of months ago. The current %pF is very convenient to print a function symbol, but often we only want to print the name of the function, without its asm offset. That's what %pf does in this patch. The lowecase f has been chosen for its intuitive meaning of a 'weak kind of %pF'. The support for this new format would be welcome by the tracing code where the need to print pure function names is often needed. This is also true for other parts of the kernel: $ git-grep -E "kallsyms_lookup\(.+?\)" arch/blackfin/kernel/traps.c: symname = kallsyms_lookup(address, &symsize, &offset, &modname, namebuf); arch/powerpc/xmon/xmon.c: name = kallsyms_lookup(pc, &size, &offset, NULL, tmpstr); arch/sh/kernel/cpu/sh5/unwind.c: sym = kallsyms_lookup(pc, NULL, &offset, NULL, namebuf); arch/x86/kernel/ftrace.c: kallsyms_lookup((unsigned long) syscall, NULL, NULL, NULL, str); kernel/kprobes.c: sym = kallsyms_lookup((unsigned long)p->addr, NULL, kernel/lockdep.c: return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup((unsigned long)rec->ops->func, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, &modname, str); kernel/trace/ftrace.c: kallsyms_lookup(*ptr, NULL, NULL, NULL, str); kernel/trace/trace_functions.c: kallsyms_lookup(ip, NULL, NULL, NULL, str); kernel/trace/trace_output.c: kallsyms_lookup(address, NULL, NULL, NULL, str); Changes in v2: - Add the explanation of the %pf role for vsnprintf() and bstr_printf() - Change the comments by dropping the "asm offset" notion and only define the %pf against the actual function offset notion. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Zhaolei <zhaolei@cn.fujitsu.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20090415154817.GC5989@nowhere> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-15 17:48:18 +02:00
lib: vsprintf: add IPv4/v6 generic %p[Ii]S[pfs] format specifier In order to avoid making code that deals with printing both, IPv4 and IPv6 addresses, unnecessary complicated as for example ... if (sa.sa_family == AF_INET6) printk("... %pI6 ...", ..sin6_addr); else printk("... %pI4 ...", ..sin_addr.s_addr); ... it would be better to introduce a format specifier that can deal with those kind of situations internally; just as we have a "struct sockaddr" for generic mapping into "struct sockaddr_in" or "struct sockaddr_in6" as e.g. done in "union sctp_addr". Then, we could reduce the above statement into something like: printk("... %pIS ..", &sockaddr); In case our pointer is NULL, pointer() then deals with that already at an earlier point in time internally. While we're at it, support for both %piS/%pIS, where 'S' stands for sockaddr, comes (almost) for free. Additionally to that, postfix specifiers 'p', 'f' and 's' are supported as suggested and initially implemented in 2009 by Joe Perches [1]. Handling of those additional specifiers orientate on the initial RFC that was proposed. Also we support IPv6 compressed format specified by 'c' and various other IPv4 extensions as stated in the documentation part. Likely, there are many other areas than just SCTP in the kernel to make use of this extension as well. [1] http://patchwork.ozlabs.org/patch/31480/ Signed-off-by: Daniel Borkmann <dborkman@redhat.com> CC: Joe Perches <joe@perches.com> CC: linux-kernel@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-28 19:49:39 +02:00
lib: vsprintf: add IPv4/v6 generic %p[Ii]S[pfs] format specifier In order to avoid making code that deals with printing both, IPv4 and IPv6 addresses, unnecessary complicated as for example ... if (sa.sa_family == AF_INET6) printk("... %pI6 ...", ..sin6_addr); else printk("... %pI4 ...", ..sin_addr.s_addr); ... it would be better to introduce a format specifier that can deal with those kind of situations internally; just as we have a "struct sockaddr" for generic mapping into "struct sockaddr_in" or "struct sockaddr_in6" as e.g. done in "union sctp_addr". Then, we could reduce the above statement into something like: printk("... %pIS ..", &sockaddr); In case our pointer is NULL, pointer() then deals with that already at an earlier point in time internally. While we're at it, support for both %piS/%pIS, where 'S' stands for sockaddr, comes (almost) for free. Additionally to that, postfix specifiers 'p', 'f' and 's' are supported as suggested and initially implemented in 2009 by Joe Perches [1]. Handling of those additional specifiers orientate on the initial RFC that was proposed. Also we support IPv6 compressed format specified by 'c' and various other IPv4 extensions as stated in the documentation part. Likely, there are many other areas than just SCTP in the kernel to make use of this extension as well. [1] http://patchwork.ozlabs.org/patch/31480/ Signed-off-by: Daniel Borkmann <dborkman@redhat.com> CC: Joe Perches <joe@perches.com> CC: linux-kernel@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-28 19:49:39 +02:00
kptr_restrict for hiding kernel pointers from unprivileged users Add the %pK printk format specifier and the /proc/sys/kernel/kptr_restrict sysctl. The %pK format specifier is designed to hide exposed kernel pointers, specifically via /proc interfaces. Exposing these pointers provides an easy target for kernel write vulnerabilities, since they reveal the locations of writable structures containing easily triggerable function pointers. The behavior of %pK depends on the kptr_restrict sysctl. If kptr_restrict is set to 0, no deviation from the standard %p behavior occurs. If kptr_restrict is set to 1, the default, if the current user (intended to be a reader via seq_printf(), etc.) does not have CAP_SYSLOG (currently in the LSM tree), kernel pointers using %pK are printed as 0's. If kptr_restrict is set to 2, kernel pointers using %pK are printed as 0's regardless of privileges. Replacing with 0's was chosen over the default "(null)", which cannot be parsed by userland %p, which expects "(nil)". [akpm@linux-foundation.org: check for IRQ context when !kptr_restrict, save an indent level, s/WARN/WARN_ONCE/] [akpm@linux-foundation.org: coding-style fixup] [randy.dunlap@oracle.com: fix kernel/sysctl.c warning] Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: James Morris <jmorris@namei.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Thomas Graf <tgraf@infradead.org> Cc: Eugene Teo <eugeneteo@kernel.org> Cc: Kees Cook <kees.cook@canonical.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David S. Miller <davem@davemloft.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Eric Paris <eparis@parisplace.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-12 16:59:41 -08:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: introduce %pf format specifier A printf format specifier which would allow us to print a pure function name has been suggested by Andrew Morton a couple of months ago. The current %pF is very convenient to print a function symbol, but often we only want to print the name of the function, without its asm offset. That's what %pf does in this patch. The lowecase f has been chosen for its intuitive meaning of a 'weak kind of %pF'. The support for this new format would be welcome by the tracing code where the need to print pure function names is often needed. This is also true for other parts of the kernel: $ git-grep -E "kallsyms_lookup\(.+?\)" arch/blackfin/kernel/traps.c: symname = kallsyms_lookup(address, &symsize, &offset, &modname, namebuf); arch/powerpc/xmon/xmon.c: name = kallsyms_lookup(pc, &size, &offset, NULL, tmpstr); arch/sh/kernel/cpu/sh5/unwind.c: sym = kallsyms_lookup(pc, NULL, &offset, NULL, namebuf); arch/x86/kernel/ftrace.c: kallsyms_lookup((unsigned long) syscall, NULL, NULL, NULL, str); kernel/kprobes.c: sym = kallsyms_lookup((unsigned long)p->addr, NULL, kernel/lockdep.c: return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup((unsigned long)rec->ops->func, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, &modname, str); kernel/trace/ftrace.c: kallsyms_lookup(*ptr, NULL, NULL, NULL, str); kernel/trace/trace_functions.c: kallsyms_lookup(ip, NULL, NULL, NULL, str); kernel/trace/trace_output.c: kallsyms_lookup(address, NULL, NULL, NULL, str); Changes in v2: - Add the explanation of the %pf role for vsnprintf() and bstr_printf() - Change the comments by dropping the "asm offset" notion and only define the %pf against the actual function offset notion. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Zhaolei <zhaolei@cn.fujitsu.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20090415154817.GC5989@nowhere> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-15 17:48:18 +02:00
lib: vsprintf: add IPv4/v6 generic %p[Ii]S[pfs] format specifier In order to avoid making code that deals with printing both, IPv4 and IPv6 addresses, unnecessary complicated as for example ... if (sa.sa_family == AF_INET6) printk("... %pI6 ...", ..sin6_addr); else printk("... %pI4 ...", ..sin_addr.s_addr); ... it would be better to introduce a format specifier that can deal with those kind of situations internally; just as we have a "struct sockaddr" for generic mapping into "struct sockaddr_in" or "struct sockaddr_in6" as e.g. done in "union sctp_addr". Then, we could reduce the above statement into something like: printk("... %pIS ..", &sockaddr); In case our pointer is NULL, pointer() then deals with that already at an earlier point in time internally. While we're at it, support for both %piS/%pIS, where 'S' stands for sockaddr, comes (almost) for free. Additionally to that, postfix specifiers 'p', 'f' and 's' are supported as suggested and initially implemented in 2009 by Joe Perches [1]. Handling of those additional specifiers orientate on the initial RFC that was proposed. Also we support IPv6 compressed format specified by 'c' and various other IPv4 extensions as stated in the documentation part. Likely, there are many other areas than just SCTP in the kernel to make use of this extension as well. [1] http://patchwork.ozlabs.org/patch/31480/ Signed-off-by: Daniel Borkmann <dborkman@redhat.com> CC: Joe Perches <joe@perches.com> CC: linux-kernel@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-28 19:49:39 +02:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
kptr_restrict for hiding kernel pointers from unprivileged users Add the %pK printk format specifier and the /proc/sys/kernel/kptr_restrict sysctl. The %pK format specifier is designed to hide exposed kernel pointers, specifically via /proc interfaces. Exposing these pointers provides an easy target for kernel write vulnerabilities, since they reveal the locations of writable structures containing easily triggerable function pointers. The behavior of %pK depends on the kptr_restrict sysctl. If kptr_restrict is set to 0, no deviation from the standard %p behavior occurs. If kptr_restrict is set to 1, the default, if the current user (intended to be a reader via seq_printf(), etc.) does not have CAP_SYSLOG (currently in the LSM tree), kernel pointers using %pK are printed as 0's. If kptr_restrict is set to 2, kernel pointers using %pK are printed as 0's regardless of privileges. Replacing with 0's was chosen over the default "(null)", which cannot be parsed by userland %p, which expects "(nil)". [akpm@linux-foundation.org: check for IRQ context when !kptr_restrict, save an indent level, s/WARN/WARN_ONCE/] [akpm@linux-foundation.org: coding-style fixup] [randy.dunlap@oracle.com: fix kernel/sysctl.c warning] Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: James Morris <jmorris@namei.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Thomas Graf <tgraf@infradead.org> Cc: Eugene Teo <eugeneteo@kernel.org> Cc: Kees Cook <kees.cook@canonical.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David S. Miller <davem@davemloft.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Eric Paris <eparis@parisplace.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-12 16:59:41 -08:00
kptr_restrict for hiding kernel pointers from unprivileged users Add the %pK printk format specifier and the /proc/sys/kernel/kptr_restrict sysctl. The %pK format specifier is designed to hide exposed kernel pointers, specifically via /proc interfaces. Exposing these pointers provides an easy target for kernel write vulnerabilities, since they reveal the locations of writable structures containing easily triggerable function pointers. The behavior of %pK depends on the kptr_restrict sysctl. If kptr_restrict is set to 0, no deviation from the standard %p behavior occurs. If kptr_restrict is set to 1, the default, if the current user (intended to be a reader via seq_printf(), etc.) does not have CAP_SYSLOG (currently in the LSM tree), kernel pointers using %pK are printed as 0's. If kptr_restrict is set to 2, kernel pointers using %pK are printed as 0's regardless of privileges. Replacing with 0's was chosen over the default "(null)", which cannot be parsed by userland %p, which expects "(nil)". [akpm@linux-foundation.org: check for IRQ context when !kptr_restrict, save an indent level, s/WARN/WARN_ONCE/] [akpm@linux-foundation.org: coding-style fixup] [randy.dunlap@oracle.com: fix kernel/sysctl.c warning] Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: James Morris <jmorris@namei.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Thomas Graf <tgraf@infradead.org> Cc: Eugene Teo <eugeneteo@kernel.org> Cc: Kees Cook <kees.cook@canonical.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David S. Miller <davem@davemloft.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Eric Paris <eparis@parisplace.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-12 16:59:41 -08:00
kptr_restrict for hiding kernel pointers from unprivileged users Add the %pK printk format specifier and the /proc/sys/kernel/kptr_restrict sysctl. The %pK format specifier is designed to hide exposed kernel pointers, specifically via /proc interfaces. Exposing these pointers provides an easy target for kernel write vulnerabilities, since they reveal the locations of writable structures containing easily triggerable function pointers. The behavior of %pK depends on the kptr_restrict sysctl. If kptr_restrict is set to 0, no deviation from the standard %p behavior occurs. If kptr_restrict is set to 1, the default, if the current user (intended to be a reader via seq_printf(), etc.) does not have CAP_SYSLOG (currently in the LSM tree), kernel pointers using %pK are printed as 0's. If kptr_restrict is set to 2, kernel pointers using %pK are printed as 0's regardless of privileges. Replacing with 0's was chosen over the default "(null)", which cannot be parsed by userland %p, which expects "(nil)". [akpm@linux-foundation.org: check for IRQ context when !kptr_restrict, save an indent level, s/WARN/WARN_ONCE/] [akpm@linux-foundation.org: coding-style fixup] [randy.dunlap@oracle.com: fix kernel/sysctl.c warning] Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: James Morris <jmorris@namei.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Thomas Graf <tgraf@infradead.org> Cc: Eugene Teo <eugeneteo@kernel.org> Cc: Kees Cook <kees.cook@canonical.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David S. Miller <davem@davemloft.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Eric Paris <eparis@parisplace.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-12 16:59:41 -08:00
vsprintf: check real user/group id for %pK Some setuid binaries will allow reading of files which have read permission by the real user id. This is problematic with files which use %pK because the file access permission is checked at open() time, but the kptr_restrict setting is checked at read() time. If a setuid binary opens a %pK file as an unprivileged user, and then elevates permissions before reading the file, then kernel pointer values may be leaked. This happens for example with the setuid pppd application on Ubuntu 12.04: $ head -1 /proc/kallsyms 00000000 T startup_32 $ pppd file /proc/kallsyms pppd: In file /proc/kallsyms: unrecognized option 'c1000000' This will only leak the pointer value from the first line, but other setuid binaries may leak more information. Fix this by adding a check that in addition to the current process having CAP_SYSLOG, that effective user and group ids are equal to the real ids. If a setuid binary reads the contents of a file which uses %pK then the pointer values will be printed as NULL if the real user is unprivileged. Update the sysctl documentation to reflect the changes, and also correct the documentation to state the kptr_restrict=0 is the default. This is a only temporary solution to the issue. The correct solution is to do the permission check at open() time on files, and to replace %pK with a function which checks the open() time permission. %pK uses in printk should be removed since no sane permission check can be done, and instead protected by using dmesg_restrict. Signed-off-by: Ryan Mallon <rmallon@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Joe Perches <joe@perches.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-12 15:08:51 -08:00
vsprintf: check real user/group id for %pK Some setuid binaries will allow reading of files which have read permission by the real user id. This is problematic with files which use %pK because the file access permission is checked at open() time, but the kptr_restrict setting is checked at read() time. If a setuid binary opens a %pK file as an unprivileged user, and then elevates permissions before reading the file, then kernel pointer values may be leaked. This happens for example with the setuid pppd application on Ubuntu 12.04: $ head -1 /proc/kallsyms 00000000 T startup_32 $ pppd file /proc/kallsyms pppd: In file /proc/kallsyms: unrecognized option 'c1000000' This will only leak the pointer value from the first line, but other setuid binaries may leak more information. Fix this by adding a check that in addition to the current process having CAP_SYSLOG, that effective user and group ids are equal to the real ids. If a setuid binary reads the contents of a file which uses %pK then the pointer values will be printed as NULL if the real user is unprivileged. Update the sysctl documentation to reflect the changes, and also correct the documentation to state the kptr_restrict=0 is the default. This is a only temporary solution to the issue. The correct solution is to do the permission check at open() time on files, and to replace %pK with a function which checks the open() time permission. %pK uses in printk should be removed since no sane permission check can be done, and instead protected by using dmesg_restrict. Signed-off-by: Ryan Mallon <rmallon@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Joe Perches <joe@perches.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-12 15:08:51 -08:00
vsprintf: check real user/group id for %pK Some setuid binaries will allow reading of files which have read permission by the real user id. This is problematic with files which use %pK because the file access permission is checked at open() time, but the kptr_restrict setting is checked at read() time. If a setuid binary opens a %pK file as an unprivileged user, and then elevates permissions before reading the file, then kernel pointer values may be leaked. This happens for example with the setuid pppd application on Ubuntu 12.04: $ head -1 /proc/kallsyms 00000000 T startup_32 $ pppd file /proc/kallsyms pppd: In file /proc/kallsyms: unrecognized option 'c1000000' This will only leak the pointer value from the first line, but other setuid binaries may leak more information. Fix this by adding a check that in addition to the current process having CAP_SYSLOG, that effective user and group ids are equal to the real ids. If a setuid binary reads the contents of a file which uses %pK then the pointer values will be printed as NULL if the real user is unprivileged. Update the sysctl documentation to reflect the changes, and also correct the documentation to state the kptr_restrict=0 is the default. This is a only temporary solution to the issue. The correct solution is to do the permission check at open() time on files, and to replace %pK with a function which checks the open() time permission. %pK uses in printk should be removed since no sane permission check can be done, and instead protected by using dmesg_restrict. Signed-off-by: Ryan Mallon <rmallon@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Joe Perches <joe@perches.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-12 15:08:51 -08:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: introduce %pf format specifier A printf format specifier which would allow us to print a pure function name has been suggested by Andrew Morton a couple of months ago. The current %pF is very convenient to print a function symbol, but often we only want to print the name of the function, without its asm offset. That's what %pf does in this patch. The lowecase f has been chosen for its intuitive meaning of a 'weak kind of %pF'. The support for this new format would be welcome by the tracing code where the need to print pure function names is often needed. This is also true for other parts of the kernel: $ git-grep -E "kallsyms_lookup\(.+?\)" arch/blackfin/kernel/traps.c: symname = kallsyms_lookup(address, &symsize, &offset, &modname, namebuf); arch/powerpc/xmon/xmon.c: name = kallsyms_lookup(pc, &size, &offset, NULL, tmpstr); arch/sh/kernel/cpu/sh5/unwind.c: sym = kallsyms_lookup(pc, NULL, &offset, NULL, namebuf); arch/x86/kernel/ftrace.c: kallsyms_lookup((unsigned long) syscall, NULL, NULL, NULL, str); kernel/kprobes.c: sym = kallsyms_lookup((unsigned long)p->addr, NULL, kernel/lockdep.c: return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup((unsigned long)rec->ops->func, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); kernel/trace/ftrace.c: kallsyms_lookup(rec->ip, NULL, NULL, &modname, str); kernel/trace/ftrace.c: kallsyms_lookup(*ptr, NULL, NULL, NULL, str); kernel/trace/trace_functions.c: kallsyms_lookup(ip, NULL, NULL, NULL, str); kernel/trace/trace_output.c: kallsyms_lookup(address, NULL, NULL, NULL, str); Changes in v2: - Add the explanation of the %pf role for vsnprintf() and bstr_printf() - Change the comments by dropping the "asm offset" notion and only define the %pf against the actual function offset notion. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Zhaolei <zhaolei@cn.fujitsu.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20090415154817.GC5989@nowhere> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-15 17:48:18 +02:00
lib: vsprintf: add IPv4/v6 generic %p[Ii]S[pfs] format specifier In order to avoid making code that deals with printing both, IPv4 and IPv6 addresses, unnecessary complicated as for example ... if (sa.sa_family == AF_INET6) printk("... %pI6 ...", ..sin6_addr); else printk("... %pI4 ...", ..sin_addr.s_addr); ... it would be better to introduce a format specifier that can deal with those kind of situations internally; just as we have a "struct sockaddr" for generic mapping into "struct sockaddr_in" or "struct sockaddr_in6" as e.g. done in "union sctp_addr". Then, we could reduce the above statement into something like: printk("... %pIS ..", &sockaddr); In case our pointer is NULL, pointer() then deals with that already at an earlier point in time internally. While we're at it, support for both %piS/%pIS, where 'S' stands for sockaddr, comes (almost) for free. Additionally to that, postfix specifiers 'p', 'f' and 's' are supported as suggested and initially implemented in 2009 by Joe Perches [1]. Handling of those additional specifiers orientate on the initial RFC that was proposed. Also we support IPv6 compressed format specified by 'c' and various other IPv4 extensions as stated in the documentation part. Likely, there are many other areas than just SCTP in the kernel to make use of this extension as well. [1] http://patchwork.ozlabs.org/patch/31480/ Signed-off-by: Daniel Borkmann <dborkman@redhat.com> CC: Joe Perches <joe@perches.com> CC: linux-kernel@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-28 19:49:39 +02:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
vsprintf: unify the format decoding layer for its 3 users An new optimization is making its way to ftrace. Its purpose is to make trace_printk() consuming less memory and be faster. Written by Lai Jiangshan, the approach is to delay the formatting job from tracing time to output time. Currently, a call to trace_printk() will format the whole string and insert it into the ring buffer. Then you can read it on /debug/tracing/trace file. The new implementation stores the address of the format string and the binary parameters into the ring buffer, making the packet more compact and faster to insert. Later, when the user exports the traces, the format string is retrieved with the binary parameters and the formatting job is eventually done. The new implementation rewrites a lot of format decoding bits from vsnprintf() function, making now 3 differents functions to maintain in their duplicated parts of printf format decoding bits. Suggested by Ingo Molnar, this patch tries to factorize the most possible common bits from these functions. The real common part between them is the format decoding. Although they do somewhat similar jobs, their way to export or import the parameters is very different. Thus, only the decoding layer is extracted, unless you see other parts that could be worth factorized. Changes in V2: - Address a suggestion from Linus to group the format_decode() parameters inside a structure. Changes in v3: - Address other cleanups suggested by Ingo and Linus such as passing the printf_spec struct to the format helpers: pointer()/number()/string() Note that this struct is passed by copy and not by address. This is to avoid side effects because these functions often change these values and the changes shoudn't be persistant when a callee helper returns. It would be too risky. - Various cleanups (code alignement, switch/case instead of if/else fountains). - Fix a bug that printed the first format specifier following a %p Changes in v4: - drop unapropriate const qualifier loss while casting fmt to a char * (thanks to Vegard Nossum for having pointed this out). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:50 +01:00
tree-wide: convert open calls to remove spaces to skip_spaces() lib function Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-14 18:01:06 -08:00
tree-wide: convert open calls to remove spaces to skip_spaces() lib function Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-14 18:01:06 -08:00
tree-wide: convert open calls to remove spaces to skip_spaces() lib function Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-14 18:01:06 -08:00