In order to save power the device should be put to low power states
whenever it is not being used. We implement this by enabling minimal
runtime PM support.
There isn't much to do for the device itself as it is disabled once the
last transfer is completed but subsystem/domain runtime PM hooks can save
more power by power gating the device etc.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
If IC_EMPTYFIFO_HOLD_MASTER_EN is set to one, the DesignWare I2C controller
doesn't generate STOP on the bus when the FIFO is empty. This violates the
rules of Linux I2C stack as it requires that the STOP is issued once the
i2c_transfer() is finished.
However, there is no way to detect this from the hardware registers, so we
must make sure that the STOP bit is always set once the last byte of the
last message is transferred.
This patch is based on the work of Dirk Brandewie.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
avoid these checkpatch.pl issues :
- ERROR: "foo * bar" should be "foo *bar"
- ERROR: switch and case should be at the same indent
- ERROR: "(foo*)" should be "(foo *)"
- ERROR: do not use assignment in if condition
- ERROR: space required before the open parenthesis '('
- WARNING: suspect code indent for conditional statements
- WARNING: quoted string split across lines
- WARNING: space prohibited between function name and open parenthesis '('
- WARNING: line over 80 characters
also add spaces around some "+", "=", "*"
Signed-off-by: Laurent Navet <laurent.navet@gmail.com>
Reviewed-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
As the at24 driver is able handle a bunch of serial storage chips other than
EEPROMs this is now mentioned in Kconfig.
Signed-off-by: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
i2c_smbus_process_call has no users in the kernel, so this can be
removed. Documentation for the same has been updated accordingly.
Fixes following sparse warning.
drivers/i2c/i2c-core.c:1871:5: warning: symbol 'i2c_smbus_process_call'
was not declared. Should it be static?
[wsa: updated the documentation]
Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
We have historically hard-coded entry points in head.S just so it's easy
to build the executable/bzImage headers with references to them.
Unfortunately, this leads to boot loaders abusing these "known" addresses
even when they are *explicitly* told that they "should look at the ELF
header to find this address, as it may change in the future". And even
when the address in question *has* actually been changed in the past,
without fanfare or thought to compatibility.
Thus we have bootloaders doing stunningly broken things like jumping
to offset 0x200 in the kernel startup code in 64-bit mode, *hoping*
that startup_64 is still there (it has moved at least once
before). And hoping that it's actually a 64-bit kernel despite the
fact that we don't give them any indication of that fact.
This patch should hopefully remove the temptation to abuse internal
addresses in future, where sternly worded comments have not sufficed.
Instead of having hard-coded addresses and saying "please don't abuse
these", we actually pull the addresses out of the ELF payload into
zoffset.h, and make build.c shove them back into the right places in
the bzImage header.
Rather than including zoffset.h into build.c and thus having to rebuild
the tool for every kernel build, we parse it instead. The parsing code
is small and simple.
This patch doesn't actually move any of the interesting entry points, so
any offending bootloader will still continue to "work" after this patch
is applied. For some version of "work" which includes jumping into the
compressed payload and crashing, if the bzImage it's given is a 32-bit
kernel. No change there then.
[ hpa: some of the issues in the description are addressed or
retconned by the 2.12 boot protocol. This patch has been edited to
only remove fixed addresses that were *not* thus retconned. ]
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Link: http://lkml.kernel.org/r/1358513837.2397.247.camel@shinybook.infradead.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Matt Fleming <matt.fleming@intel.com>
The 'Attributes' argument to pci->Attributes() function is 64-bit. So
when invoking in 32-bit mode it takes two registers, not just one.
This fixes memory corruption when booting via the 32-bit EFI boot stub.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/1358513837.2397.247.camel@shinybook.infradead.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Matt Fleming <matt.fleming@intel.com>
If the bootloader calls the EFI handover entry point as a standard function
call, then it'll have a return address on the stack. We need to pop that
before calling efi_main(), or the arguments will all be out of position on
the stack.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/1358513837.2397.247.camel@shinybook.infradead.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Matt Fleming <matt.fleming@intel.com>
When booting under OVMF we have precisely one GOP device, and it
implements the ConOut protocol.
We break out of the loop when we look at it... and then promptly abort
because 'first_gop' never gets set. We should set first_gop *before*
breaking out of the loop. Yes, it doesn't really mean "first" any more,
but that doesn't matter. It's only a flag to indicate that a suitable
GOP was found.
In fact, we'd do just as well to initialise 'width' to zero in this
function, then just check *that* instead of first_gop. But I'll do the
minimal fix for now (and for stable@).
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/1358513837.2397.247.camel@shinybook.infradead.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Force the crtc mem requests on/off immediately rather
than waiting for the double buffered updates to kick in.
Seems we miss the update in certain conditions. Also
handle the DCE6 case.
Signed-off-by: Christopher Staite <chris@yourdreamnet.co.uk>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
This patch allow the unprivileged user to mount mqueuefs in
user ns.
If two userns share the same ipcns,the files in mqueue fs
should be seen in both these two userns.
If the userns has its own ipcns,it has its own mqueue fs too.
ipcns has already done this job well.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
There is no real reason to use a rwlock for devtree_lock. It even
could be a mutex, but unfortunately it's locked from cpu hotplug
paths which can't schedule :(
So it needs to become a raw lock on rt as well. The devtree_lock would
be the only user of a raw_rw_lock, so we are better off cleaning up the
recursive locking paths which allows us to convert devtree_lock to a
read_lock.
Here we do the standard thing of introducing __foo() as the "raw"
version of foo(), so that we can take better control of the locking.
The "raw" versions are not exported and are for internal use within
the file itself.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
The comments here say that the /* Max event is 61 char */ but in 2003 we
changed the event format and now the max event size is 75. The longest
event is:
"Discovered %08x (%s) behind %08x {hints %02X-%02X}\n",
12345678901 23 456789012 34567890 1 2 3
+8 +21 +8 +2 +2 +1
= 75 characters.
There was a check to return -EOVERFLOW if the user gave us a "count"
value that was less than 64. Raising it to 75 might break backwards
compatability. Instead I removed the check and now it returns a
truncated string if "count" is too low.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If state != IP_VS_STATE_BACKUP then tinfo->buf is uninitialized. If
kthread_run() fails then it means we free random memory resulting in an
oops.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Replace occurences of gpio_request() and gpio_direction_*() by calls to
gpio_request_one().
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Replace occurences of gpio_request() and gpio_direction_*() by calls to
gpio_request_one().
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Replace occurences of gpio_request() and gpio_direction_*() by calls to
gpio_request_one().
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Replace occurences of gpio_request() and gpio_direction_*() by calls to
gpio_request_one().
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
The GPIO is already configured as an output, there's no reason to use
gpio_direction_output() just to set the output value. Use
gpio_set_value() instead.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Replace occurences of gpio_request() and gpio_direction_*() by calls to
gpio_request_one().
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Replace occurences of gpio_request() and gpio_direction_*() by calls to
gpio_request_one().
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Replace occurences of gpio_request() and gpio_direction_*() by calls to
gpio_request_one().
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
While sctp handling a duplicate COOKIE-ECHO and the action is
'Association restart', sctp_sf_do_dupcook_a() will processing
the unexpected COOKIE-ECHO for peer restart, but it does not set
the association state to SCTP_STATE_ESTABLISHED, so the association
could stuck in SCTP_STATE_SHUTDOWN_PENDING state forever.
This violates the sctp specification:
RFC 4960 5.2.4. Handle a COOKIE ECHO when a TCB Exists
Action
A) In this case, the peer may have restarted. .....
After this, the endpoint shall enter the ESTABLISHED state.
To resolve this problem, adding a SCTP_CMD_NEW_STATE cmd to the
command list before SCTP_CMD_REPLY cmd, this will set the restart
association to SCTP_STATE_ESTABLISHED state properly and also avoid
I-bit being set in the DATA chunk header when COOKIE_ACK is bundled
with DATA chunks.
Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We did this for IPv4 in b49d3c1e1c "net: ipmr: limit MRT_TABLE
identifiers" but we need to do it for IPv6 as well. On IPv6 the name
is "pim6reg" instead of "pimreg" so there is one less digit allowed.
The strcpy() is in ip6mr_reg_vif().
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Control of receive descriptor must not be returned to ethernet chipset
before vlan tag processing is done.
VLAN tag receive word is now reset both in normal and error path.
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Spotted-by: Timo Teras <timo.teras@iki.fi>
Cc: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
commit 9992c2e (net: cdc_ncm: workaround for missing CDC Union)
added code to lookup an IAD for the interface we are probing.
This is redundant. The USB core has already done the lookup
and saved the result in the USB interface struct. Use that
instead.
Cc: Greg Suarez <gsuarez@smithmicro.com>
Cc: Alexey Orishko <alexey.orishko@stericsson.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
- fix an skb memleak in DAT
- fix the ARP filtering routine in DAT by preventing bogus entries to overwrite
already existing ones in the local cache.
- fix the ARP filtering routine in DAT by preventing it to parse and add to the
cache bogus entries
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Merge tag 'batman-adv-fix-for-davem' of git://git.open-mesh.org/linux-merge
Included changes ares:
- fix an skb memleak in DAT
- fix the ARP filtering routine in DAT by preventing bogus entries to overwrite
already existing ones in the local cache.
- fix the ARP filtering routine in DAT by preventing it to parse and add to the
cache bogus entries
Signed-off-by: David S. Miller <davem@davemloft.net>
Jeff Kirsher says:
====================
This series contains updates to e1000e only. All the updates come
from Bruce Allan and most of the patch fix or enable features on
i217/i218. Most notably is patch 03 "e1000e: add support for IEEE-1588
PTP", which is v2 of the patch based on feedback from Stephen Hemminger.
Also patch 04 "e1000e: enable ECC on I217/I218 to catch packet buffer
memory errors" should be queued up for stable (as well as net) trees, but
the patch does not apply cleanly to either of those trees currently.
So I will work with Bruce to provide a version of the patch which will
apply cleanly to net (and stable) and we can queue it up at that point
for stable 3.5 tree.
The remaining patches are general cleanups of the code.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Define the 2.12 bzImage boot protocol: add xloadflags and additional
fields to allow the command line, initramfs and struct boot_params to
live above the 4 GiB mark.
The xloadflags now communicates if this is a 64-bit kernel with the
legacy 64-bit entry point and which of the EFI handover entry points
are supported.
Avoid adding new read flags to loadflags because of claimed
bootloaders testing the whole byte for == 1 to determine bzImageness
at least until the issue can be researched further.
This is based on patches by Yinghai Lu and David Woodhouse.
Originally-by: Yinghai Lu <yinghai@kernel.org>
Originally-by: David Woodhouse <dwmw2@infradead.org>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: David Woodhouse <dwmw2@infradead.org>
Acked-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1359058816-7615-26-git-send-email-yinghai@kernel.org
Cc: Rob Landley <rob@landley.net>
Cc: Gokul Caushik <caushik1@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joe Millenbach <jmillenbach@gmail.com>
Our suspend code touches a lot of registers all over the place, so we
need to enable the power well before suspending.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
[danvet: Fixup compilation by stealing the header decl from the
dynamic power wells patch.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Instead of setting it at the beginning of haswell_crtc_mode_set, let's
set it at the beginning of intel_crtc_mode_set. When
intel_crt_mode_set calls drm_vblank_pre_modeset we already need to
have the transcoder_edp correctly set, because eventually
drm_vblank_pre_modeset calls functions that call i915_pipe_enabled
from i915_irq.c, which will read PIPECONF(cpu_transcoder).
This is a bug that affects us since we added support for
TRANSCODER_EDP, but I was only able to see the problem after
suspending a machine with the power well disabled (got an "unclaimed
register" error.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
One of the early return cases missed the mutex unlocking. Hilarity
ensued.
This regression has been introduced in
commit 7b24056be6
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Wed Dec 12 00:35:33 2012 +0100
drm: don't hold crtc mutexes for connector ->detect callbacks
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59750
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Cancan Feng <cancan.feng@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
We do need to start the lease recovery thread prior to waiting for the
client initialisation to complete in NFSv4.1.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Ben Greear <greearb@candelatech.com>
Cc: stable@vger.kernel.org [>=3.7]
If walking the list in nfs4[01]_walk_client_list fails, then the most
likely explanation is that the server dropped the clientid before we
actually managed to confirm it. As long as our nfs_client is the very
last one in the list to be tested, the caller can be assured that this
is the case when the final return value is NFS4ERR_STALE_CLIENTID.
Reported-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org [>=3.7]
Tested-by: Ben Greear <greearb@candelatech.com>
The reference counting in nfs4_init_client assumes wongly that it
is safe for nfs4_discover_server_trunking() to return a pointer to a
nfs_client prior to bumping the reference count.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Ben Greear <greearb@candelatech.com>
Cc: stable@vger.kernel.org [>=3.7]
Currently, nfs_xdev_mount converts all errors from clone_server() to
ENOMEM, which can then leak to userspace (for instance to 'mount'). Fix that.
Also ensure that if nfs_fs_mount_common() returns an error, we
don't dprintk(0)...
The regression originated in commit 3d176e3fe4
(NFS: Use nfs_fs_mount_common() for xdev mounts)
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>= 3.5]
Fix /proc/acpi/wakeup for devices without bus or parent
This patch fixes printing the wakeup status for devices without a bus
or parent, such as laptop lid switches and sleep buttons. These devices
have an empty physical_node_list, because acpi_bind_one is never run
for them.
[rjw: White space and coding style.]
Signed-off-by: Andreas Fleig <andreasfleig@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There is no guarantee that acpi_bus_scan() and acpi_bus_trim() will
not be run in parallel for the same scope of the ACPI namespace,
which may lead to a great deal of confusion, so introduce a new mutex
to prevent that from happening.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
While remotely reading the cputime of a task running in a
full dynticks CPU, the values stored in utime/stime fields
of struct task_struct may be stale. Its values may be those
of the last kernel <-> user transition time snapshot and
we need to add the tickless time spent since this snapshot.
To fix this, flush the cputime of the dynticks CPUs on
kernel <-> user transition and record the time / context
where we did this. Then on top of this snapshot and the current
time, perform the fixup on the reader side from task_times()
accessors.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
[fixed kvm module related build errors]
Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com>
Do some ground preparatory work before adding guest_enter()
and guest_exit() context tracking callbacks. Those will
be later used to read the guest cputime safely when we
run in full dynticks mode.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
This is in preparation for the full dynticks feature. While
remotely reading the cputime of a task running in a full
dynticks CPU, we'll need to do some extra-computation. This
way we can account the time it spent tickless in userspace
since its last cputime snapshot.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Allow to dynamically switch between tick and virtual based
cputime accounting. This way we can provide a kind of "on-demand"
virtual based cputime accounting. In this mode, the kernel relies
on the context tracking subsystem to dynamically probe on kernel
boundaries.
This is in preparation for being able to stop the timer tick in
more places than just the idle state. Doing so will depend on
CONFIG_VIRT_CPU_ACCOUNTING_GEN which makes it possible to account
the cputime without the tick by hooking on kernel/user boundaries.
Depending whether the tick is stopped or not, we can switch between
tick and vtime based accounting anytime in order to minimize the
overhead associated to user hooks.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
If we want to stop the tick further idle, we need to be
able to account the cputime without using the tick.
Virtual based cputime accounting solves that problem by
hooking into kernel/user boundaries.
However implementing CONFIG_VIRT_CPU_ACCOUNTING require
low level hooks and involves more overhead. But we already
have a generic context tracking subsystem that is required
for RCU needs by archs which plan to shut down the tick
outside idle.
This patch implements a generic virtual based cputime
accounting that relies on these generic kernel/user hooks.
There are some upsides of doing this:
- This requires no arch code to implement CONFIG_VIRT_CPU_ACCOUNTING
if context tracking is already built (already necessary for RCU in full
tickless mode).
- We can rely on the generic context tracking subsystem to dynamically
(de)activate the hooks, so that we can switch anytime between virtual
and tick based accounting. This way we don't have the overhead
of the virtual accounting when the tick is running periodically.
And one downside:
- There is probably more overhead than a native virtual based cputime
accounting. But this relies on hooks that are already set anyway.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
If the architecture doesn't provide an implementation of
nsecs_to_cputime(), the cputime accounting core uses a
default one that converts the nanoseconds to jiffies. However
this only makes sense if we use the jiffies based cputime.
For now it doesn't matter much because this API is only
called on code that uses jiffies based cputime accounting.
But the code may evolve and this API may be used more
broadly in the future. Keeping this default implementation
around is very error prone as it may introduce a bug and
hide it on architectures that don't override this API.
Fix this by moving this definition to the jiffies based
cputime headers as it is the only place where it belongs to.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
The full dynticks cputime accounting that we'll soon introduce
will rely on sched_clock(). And its clock can have a per
nanosecond granularity.
To prepare for this, we need to have a cputime_t implementation
that has this precision.
ia64 virtual cputime accounting already uses that granularity
so all we need is to librarize its implementation in the asm
generic headers.
Also librarize the default per jiffy granularity cputime_t
as well so that we can easily pick either implementation
depending on the cputime accounting config we choose.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
This driver is simple, uses the latest interfaces and contains few if
any controversial elements. All of its interfaces have been in place
for a long time now. Hence let's move it out of staging.
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Peter Meerwald <pmeerw@pmeerw.net>
