This is the recovery side of the btree block owner change operation
performed by swapext on CRC enabled filesystems. We detect that an
owner change is needed by the flag that has been placed on the inode
log format flag field. Because the inode recovery is being replayed
after the buffers that make up the BMBT in the given checkpoint, we
can walk all the buffers and directly modify them when we see the
flag set on an inode.
Because the inode can be relogged and hence present in multiple
chekpoints with the "change owner" flag set, we could do multiple
passes across the inode to do this change. While this isn't optimal,
we can't directly ignore the flag as there may be multiple
independent swap extent operations being replayed on the same inode
in different checkpoints so we can't ignore them.
Further, because the owner change operation uses ordered buffers, we
might have buffers that are newer on disk than the current
checkpoint and so already have the owner changed in them. Hence we
cannot just peek at a buffer in the tree and check that it has the
correct owner and assume that the change was completed.
So, for the moment just brute force the owner change every time we
see an inode with the flag set. Note that we have to be careful here
because the owner of the buffers may point to either the old owner
or the new owner. Currently the verifier can't verify the owner
directly, so there is no failure case here right now. If we verify
the owner exactly in future, then we'll have to take this into
account.
This was tested in terms of normal operation via xfstests - all of
the fsr tests now pass without failure. however, we really need to
modify xfs/227 to stress v3 inodes correctly to ensure we fully
cover this case for v5 filesystems.
In terms of recovery testing, I used a hacked version of xfs_fsr
that held the temp inode open for a few seconds before exiting so
that the filesystem could be shut down with an open owner change
recovery flags set on at least the temp inode. fsr leaves the temp
inode unlinked and in btree format, so this was necessary for the
owner change to be reliably replayed.
logprint confirmed the tmp inode in the log had the correct flag set:
INO: cnt:3 total:3 a:0x69e9e0 len:56 a:0x69ea20 len:176 a:0x69eae0 len:88
INODE: #regs:3 ino:0x44 flags:0x209 dsize:88
^^^^^
0x200 is set, indicating a data fork owner change needed to be
replayed on inode 0x44. A printk in the revoery code confirmed that
the inode change was recovered:
XFS (vdc): Mounting Filesystem
XFS (vdc): Starting recovery (logdev: internal)
recovering owner change ino 0x44
XFS (vdc): Version 5 superblock detected. This kernel L support enabled!
Use of these features in this kernel is at your own risk!
XFS (vdc): Ending recovery (logdev: internal)
The script used to test this was:
$ cat ./recovery-fsr.sh
#!/bin/bash
dev=/dev/vdc
mntpt=/mnt/scratch
testfile=$mntpt/testfile
umount $mntpt
mkfs.xfs -f -m crc=1 $dev
mount $dev $mntpt
chmod 777 $mntpt
for i in `seq 10000 -1 0`; do
xfs_io -f -d -c "pwrite $(($i * 4096)) 4096" $testfile > /dev/null 2>&1
done
xfs_bmap -vp $testfile |head -20
xfs_fsr -d -v $testfile &
sleep 10
/home/dave/src/xfstests-dev/src/godown -f $mntpt
wait
umount $mntpt
xfs_logprint -t $dev |tail -20
time mount $dev $mntpt
xfs_bmap -vp $testfile
umount $mntpt
$
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Provide the rail supply voltage through descriptor to the
core and remove the callbacks which implement the get_voltage
and list_voltage.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
If given rail has the single voltage (n_voltages = 1) then provide the
rail voltage through regulator descriptor so that core can use this
value for finding voltage.
This will avoid the implementation of the callback for get_voltage() or
list_voltage() callback on regulator driver.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
If CONFIG_OF=n:
drivers/regulator/da9063-regulator.c: In function ‘da9063_parse_regulators_dt’:
drivers/regulator/da9063-regulator.c:712: warning: passing argument 1 of ‘PTR_ERR’ makes pointer from integer without a cast
drivers/regulator/da9063-regulator.c:712: warning: return makes pointer from integer without a cast
Use ERR_PTR() to encode an error code in a pointer.
PTR_ERR() is meant to decode an error code from a pointer.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
The operation status is decoded in decode_op_hdr.
Stop the print_overflow message that is always hit without this patch:
nfs: decode_free_stateid: prematurely hit end of receive buffer. Remaining
buffer length is 0 words.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
'irq' was not released when clk_prepare_enable failed.
Fix it.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
__fscache_check_consistency() does not decrement the count of operations
active after it finishes in the success case. This leads to a hung tasks on
cookie de-registration (commonly in inode eviction).
INFO: task kworker/1:2:4214 blocked for more than 120 seconds.
kworker/1:2 D ffff880443513fc0 0 4214 2 0x00000000
Workqueue: ceph-msgr con_work [libceph]
...
Call Trace:
[<ffffffff81569fc6>] ? _raw_spin_unlock_irqrestore+0x16/0x20
[<ffffffffa0016570>] ? fscache_wait_bit_interruptible+0x30/0x30 [fscache]
[<ffffffff81568d09>] schedule+0x29/0x70
[<ffffffffa001657e>] fscache_wait_atomic_t+0xe/0x20 [fscache]
[<ffffffff815665cf>] out_of_line_wait_on_atomic_t+0x9f/0xe0
[<ffffffff81083560>] ? autoremove_wake_function+0x40/0x40
[<ffffffffa0015a9c>] __fscache_relinquish_cookie+0x15c/0x310 [fscache]
[<ffffffffa00a4fae>] ceph_fscache_unregister_inode_cookie+0x3e/0x50 [ceph]
[<ffffffffa007e373>] ceph_destroy_inode+0x33/0x200 [ceph]
[<ffffffff811c13ae>] ? __fsnotify_inode_delete+0xe/0x10
[<ffffffff8119ba1c>] destroy_inode+0x3c/0x70
[<ffffffff8119bb69>] evict+0x119/0x1b0
Signed-off-by: Milosz Tanski <milosz@adfin.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sage Weil <sage@inktank.com>
These legacy drivers were removed in commit
9c75fc8c5c ("CRIS: Remove legacy RTC
drivers"). Now remove their last traces in two Kconfig files and one
Makefile.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jesper Nilsson <jespern@axis.com>
The Kconfig symbol OOM_REBOOT got added in v2.6.25. It has never been
used. Its entry can safely be removed.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
For CRC enabled filesystems, we can't just swap inode forks from one
inode to another when defragmenting a file - the blocks in the inode
fork bmap btree contain pointers back to the owner inode. Hence if
we are to swap the inode forks we have to atomically modify every
block in the btree during the transaction.
We are doing an entire fork swap here, so we could create a new
transaction item type that indicates we are changing the owner of a
certain structure from one value to another. If we combine this with
ordered buffer logging to modify all the buffers in the tree, then
we can change the buffers in the tree without needing log space for
the operation. However, this then requires log recovery to perform
the modification of the owner information of the objects/structures
in question.
This does introduce some interesting ordering details into recovery:
we have to make sure that the owner change replay occurs after the
change that moves the objects is made, not before. Hence we can't
use a separate log item for this as we have no guarantee of strict
ordering between multiple items in the log due to the relogging
action of asynchronous transaction commits. Hence there is no
"generic" method we can use for changing the ownership of arbitrary
metadata structures.
For inode forks, however, there is a simple method of communicating
that the fork contents need the owner rewritten - we can pass a
inode log format flag for the fork for the transaction that does a
fork swap. This flag will then follow the inode fork through
relogging actions so when the swap actually gets replayed the
ownership can be changed immediately by log recovery. So that gives
us a simple method of "whole fork" exchange between two inodes.
This is relatively simple to implement, so it makes sense to do this
as an initial implementation to support xfs_fsr on CRC enabled
filesytems in the same manner as we do on existing filesystems. This
commit introduces the swapext driven functionality, the recovery
functionality will be in a separate patch.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
intel_ddi_enable_transcoder_func() picked the sync flags from crtc->mode
instead of the pipe config adjusted_mode. Fix the problem and hopefully
rid my HSW machine of the remaining pipe config warnings.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The purpose of the function is to find out whether the object is still
bound in any address space. This can be easily checked by looking at the
vma currently associated with the object, rather than asking if any of
the global address spaces have an active vma on the object.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
It is not needed to include asm/dma-contiguous.h header to compile
reserved memory initialization code, so remove it to avoid build break
on architectures without CMA support.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
bd8815a6d8 ("cgroup: make css_for_each_descendant() and friends
include the origin css in the iteration") updated cgroup descendant
iterators to include the origin css; unfortuantely, it forgot to drop
special case handling in css_next_descendant_post() for empty subtree
leading to failure to visit the origin css without any child.
Fix it by dropping the special case handling and always returning the
leftmost descendant on the first iteration.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Ignoring the legacy DRI1 code, and a couple of special cases (to be
discussed later), all access to the ring is mediated through requests.
The first write to a ring will grab a seqno and mark the ring as having
an outstanding_lazy_request. Either through explicitly adding a request
after an execbuffer or through an implicit wait (either by the CPU or by
a semaphore), that sequence of writes will be terminated with a request.
So we can ellide all the intervening writes to the tail register and
send the entire command stream to the GPU at once. This will reduce the
number of *serialising* writes to the tail register by a factor or 3-5
times (depending upon architecture and number of workarounds, context
switches, etc involved). This becomes even more noticeable when the
register write is overloaded with a number of debugging tools. The
astute reader will wonder if it is then possible to overflow the ring
with a single command. It is not. When we start a command sequence to
the ring, we check for available space and issue a wait in case we have
not. The ring wait will in this case be forced to flush the outstanding
register write and then poll the ACTHD for sufficient space to continue.
The exception to the rule where everything is inside a request are a few
initialisation cases where we may want to write GPU commands via the CS
before userspace wakes up and page flips.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Casting the return value which is a void pointer is redundant.
The conversion from void pointer to any other pointer type is
guaranteed by the C programming language.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This gets rid of this warning:
drivers/hwmon/hwmon-vid.c: In function 'get_via_model_d_vrm':
drivers/hwmon/hwmon-vid.c:249:27: warning: variable 'dummy' set but not used
[-Wunused-but-set-variable]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jean Delvare <khali@linux-fr.org>
As per datasheet (Referred TPS65913), the on-time for LDO is
500micro second. If LDO6 is in vibrator mode then the on-time
is 2000us.
Set the enable_time on regulator descriptor accordingly.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Instead of just a flag bit for each of the positive/negative sync
modes drm actually uses a separate flag for each ... This upsets the
modeset checker since the adjusted mode filled out at modeset time
doesn't match the one reconstructed at check time (since the
->get_config callback already gets this right).
Reported-by: Knut Petersen <Knut_Petersen@t-online.de>
Cc: Knut Petersen <Knut_Petersen@t-online.de>
References: http://www.gossamer-threads.com/lists/linux/kernel/1778688?do=post_view_threaded
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Calling kfree() to clean up the memory obtained from spi_alloc_master() is
wrong as this is done in spi_master_release() when spi_master->dev's refcount
reaches zero.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Pull the expected max WM level determinations out to a separate
function. Will have another user soon.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Unify the code a bit to use ilk_compute_wm_level for all watermark
levels.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
hsw_pipe_wm_parameters and hsw_wm_maximums typically are read only. Make
them const.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Make the call to intel_update_watermarks() just once or twice during
modeset. Ideally it should happen independently when each plane gets
enabled/disabled, but for now it seems better to keep it in central
place. We can improve things when we get all the planes sorted out
in a better way.
When enabling set up the watermarks just before the pipe is enabled.
And when disabling we need to wait until we've marked the crtc as
inactive, as otherwise intel_crtc_active() would still think the pipe
is enabled and the computed watermarks would reflect that.
v2: Pimp up the commit message a bit
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Passing the appropriate crtc to intel_update_watermarks() should help
in avoiding needless work in the future.
v2: Avoid clash with internal 'crtc' variable in some wm functions
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
fs/btrfs/ioctl.c: In function ‘btrfs_ioctl_file_extent_same’:
fs/btrfs/ioctl.c:2802: error: implicit declaration of function ‘__put_user_unaligned’
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Replace "%8x" with "%08x".
The hex number should be shown with zero stuffed instead of spaces.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Current code uses macro to shift by 5, but there is no explanation
why there's no worry about an overflow there.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Jacob Shin <jacob.shin@amd.com>
Link: http://lkml.kernel.org/r/1378519629-10433-1-git-send-email-yinghai@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
b3af11afe0 ("x86: get rid of pt_regs argument of iopl(2)")
dropped PTREGSCALL which was also the last user of save_rest.
Drop that now-unused function too.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Link: http://lkml.kernel.org/r/1378546750-19727-1-git-send-email-bp@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 23f0d20 ("sched: Factor out code to should_we_balance()")
introduces the should_we_balance() function. This function should
return 1 if this cpu is appropriate for balancing. But the newly
introduced code doesn't do so, it returns 0 instead of 1.
This introduces performance regression, reported by Dave Chinner:
v4 filesystem v5 filesystem
3.11+xfsdev: 220k files/s 225k files/s
3.12-git 180k files/s 185k files/s
3.12-git-revert 245k files/s 247k files/s
You can find more detailed information at:
https://lkml.org/lkml/2013/9/10/1
This patch corrects the return value of should_we_balance()
function as orignally intended.
With this patch, Dave Chinner reports that the regression is gone:
v4 filesystem v5 filesystem
3.11+xfsdev: 220k files/s 225k files/s
3.12-git 180k files/s 185k files/s
3.12-git-revert 245k files/s 247k files/s
3.12-git-fix 249k files/s 248k files/s
Reported-by: Dave Chinner <dchinner@redhat.com>
Tested-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Link: http://lkml.kernel.org/r/20130910065448.GA20368@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Each dma-buf has an associated size and it's reasonable for userspace
to want to know what it is.
Since userspace already has an fd, expose the size using the
size = lseek(fd, SEEK_END, 0); lseek(fd, SEEK_CUR, 0);
idiom.
v2: Added Daniel's sugeested documentation, with minor fixups
Signed-off-by: Christopher James Halse Rogers <christopher.halse.rogers@canonical.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
that force a client to purge cache pages when a server requests it.
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
to make adding new types of lease buffers easier.
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
if we have no crtcs we need to not call the display resume code.
Reported-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
- Early stolen mem reservation from Jesse in x86 boot code. Acked by Ingo
and hpa. This was ready much earlier but somehow I've thought it'd go
in through x86 trees, hence why this is late. Avoids the pci resource
code to plant mmiobars in the middle of stolen mem and other ugliness.
- vgaarb improvements from Alex Williamson plus the fix from Ville for the
vgacon->fbcon smooth transition "feature".
- Render pageflips on ivb/hsw to avoid stalls due to the ring switching
when only flipping on the blitter (Chris).
- Deadlock fixes around our flush_workqueue which crept back in - lockdep
isn't clever enough :(
- Shrinker recursion fix from Chris - this is the thing that blew the vma
patches from Ben I've taken out of 3.12.
- Fixup for the relocation refactoring. Also an igt testcase to make sure
we don't break this again.
- Pile of smaller fixups all over, shortlog has full details.
* tag 'drm-intel-fixes-2013-09-06' of git://people.freedesktop.org/~danvet/drm-intel: (29 commits)
drm/i915: Delay disabling of VGA memory until vgacon->fbcon handoff is done
drm/i915: try not to lose backlight CBLV precision
drm/i915: Confine page flips to BCS on Valleyview
drm/i915: Skip stolen region initialisation if none is reserved
drm/i915: fix gpu hang vs. flip stall deadlocks
drm/i915: Hold an object reference whilst we shrink it
drm/i915: fix i9xx_crtc_clock_get for multiplied pixels
drm/i915: handle sdvo input pixel multiplier correctly again
drm/i915: fix hpd work vs. flush_work in the pageflip code deadlock
drm/i915: fix up the relocate_entry refactoring
drm/i915: Fix pipe config warnings when dealing with LVDS fixed mode
drm/i915: Don't call sg_free_table() if sg_alloc_table() fails
i915: Update VGA arbiter support for newer devices
vgaarb: Fix VGA decodes changes
vgaarb: Don't disable resources that are not owned
drm/i915: Pin pages whilst mapping the dma-buf
drm/i915: enable trickle feed on Haswell
x86: add early quirk for reserving Intel graphics stolen memory v5
drm/i915: split PCI IDs out into i915_drm.h v4
i915_gem: Convert kmem_cache_alloc(...GFP_ZERO) to kmem_cache_zalloc
...
Collection of random updates to the core and some end-driver fixups for
ioatdma and mv_xor:
* NUMA aware channel allocation
* Cleanup dmatest debugfs interface
* ioat: make raid-support Atom only
* mv_xor: big endian
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Merge tag 'dmaengine-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/dmaengine
Pull dmaengine update from Dan Williams:
"Collection of random updates to the core and some end-driver fixups
for ioatdma and mv_xor:
- NUMA aware channel allocation
- Cleanup dmatest debugfs interface
- ioat: make raid-support Atom only
- mv_xor: big endian
Aside from the top three commits these have all had some soak time in
-next. The top commit fixes a recent build breakage.
It has been a long while since my last pull request, hopefully it does
not show. Thanks to Vinod for keeping an eye on drivers/dma/ this
past year"
* tag 'dmaengine-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/dmaengine:
dmaengine: dma_sync_wait and dma_find_channel undefined
MAINTAINERS: update email for Dan Williams
dma: mv_xor: Fix incorrect error path
ioatdma: silence GCC warnings
dmaengine: make dma_channel_rebalance() NUMA aware
dmaengine: make dma_submit_error() return an error code
ioatdma: disable RAID on non-Atom platforms and reenable unaligned copies
mv_xor: support big endian systems using descriptor swap feature
mv_xor: use {readl, writel}_relaxed instead of __raw_{readl, writel}
dmatest: print message on debug level in case of no error
dmatest: remove IS_ERR_OR_NULL checks of debugfs calls
dmatest: make module parameters writable
Commit 7c30ed5 (cpufreq: make sure frequency transitions are
serialized) attempted to serialize frequency transitions by
adding checks to the CPUFREQ_PRECHANGE and CPUFREQ_POSTCHANGE
notifications. However, it assumed that the notifications will
always originate from the driver's .target() callback, but they
also can be triggered by cpufreq_out_of_sync() and that leads to
warnings like this on some systems:
WARNING: CPU: 0 PID: 14543 at drivers/cpufreq/cpufreq.c:317
__cpufreq_notify_transition+0x238/0x260()
In middle of another frequency transition
accompanied by a call trace similar to this one:
[<ffffffff81720daa>] dump_stack+0x46/0x58
[<ffffffff8106534c>] warn_slowpath_common+0x8c/0xc0
[<ffffffff815b8560>] ? acpi_cpufreq_target+0x320/0x320
[<ffffffff81065436>] warn_slowpath_fmt+0x46/0x50
[<ffffffff815b1ec8>] __cpufreq_notify_transition+0x238/0x260
[<ffffffff815b33be>] cpufreq_notify_transition+0x3e/0x70
[<ffffffff815b345d>] cpufreq_out_of_sync+0x6d/0xb0
[<ffffffff815b370c>] cpufreq_update_policy+0x10c/0x160
[<ffffffff815b3760>] ? cpufreq_update_policy+0x160/0x160
[<ffffffff81413813>] cpufreq_set_cur_state+0x8c/0xb5
[<ffffffff814138df>] processor_set_cur_state+0xa3/0xcf
[<ffffffff8158e13c>] thermal_cdev_update+0x9c/0xb0
[<ffffffff8159046a>] step_wise_throttle+0x5a/0x90
[<ffffffff8158e21f>] handle_thermal_trip+0x4f/0x140
[<ffffffff8158e377>] thermal_zone_device_update+0x57/0xa0
[<ffffffff81415b36>] acpi_thermal_check+0x2e/0x30
[<ffffffff81415ca0>] acpi_thermal_notify+0x40/0xdc
[<ffffffff813e7dbd>] acpi_device_notify+0x19/0x1b
[<ffffffff813f8241>] acpi_ev_notify_dispatch+0x41/0x5c
[<ffffffff813e3fbe>] acpi_os_execute_deferred+0x25/0x32
[<ffffffff81081060>] process_one_work+0x170/0x4a0
[<ffffffff81082121>] worker_thread+0x121/0x390
[<ffffffff81082000>] ? manage_workers.isra.20+0x170/0x170
[<ffffffff81088fe0>] kthread+0xc0/0xd0
[<ffffffff81088f20>] ? flush_kthread_worker+0xb0/0xb0
[<ffffffff8173582c>] ret_from_fork+0x7c/0xb0
[<ffffffff81088f20>] ? flush_kthread_worker+0xb0/0xb0
For this reason, revert commit 7c30ed5 along with the fix 266c13d
(cpufreq: Fix serialization of frequency transitions) on top of it
and we will revisit the serialization problem later.
Reported-by: Alessandro Bono <alessandro.bono@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There are places where the variable 'ret' is declared as unsigned int
and then used to store negative return values such as -EINVAL. Fix them
by declaring the variable as a signed quantity.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Commit "cpufreq: serialize calls to __cpufreq_governor()" had been a temporary
and partial solution to the race condition between writing to a cpufreq sysfs
file and taking a CPU offline. Now that we have a proper and complete solution
to that problem, remove the temporary fix.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The functions that are used to write to cpufreq sysfs files (such as
store_scaling_max_freq()) are not hotplug safe. They can race with CPU
hotplug tasks and lead to problems such as trying to acquire an already
destroyed timer-mutex etc.
Eg:
__cpufreq_remove_dev()
__cpufreq_governor(policy, CPUFREQ_GOV_STOP);
policy->governor->governor(policy, CPUFREQ_GOV_STOP);
cpufreq_governor_dbs()
case CPUFREQ_GOV_STOP:
mutex_destroy(&cpu_cdbs->timer_mutex)
cpu_cdbs->cur_policy = NULL;
<PREEMPT>
store()
__cpufreq_set_policy()
__cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
policy->governor->governor(policy, CPUFREQ_GOV_LIMITS);
case CPUFREQ_GOV_LIMITS:
mutex_lock(&cpu_cdbs->timer_mutex); <-- Warning (destroyed mutex)
if (policy->max < cpu_cdbs->cur_policy->cur) <- cur_policy == NULL
So use get_online_cpus()/put_online_cpus() in the store_*() functions, to
synchronize with CPU hotplug. However, there is an additional point to note
here: some parts of the CPU teardown in the cpufreq subsystem are done in
the CPU_POST_DEAD stage, with cpu_hotplug.lock *released*. So, using the
get/put_online_cpus() functions alone is insufficient; we should also ensure
that we don't race with those latter steps in the hotplug sequence. We can
easily achieve this by checking if the CPU is online before proceeding with
the store, since the CPU would have been marked offline by the time the
CPU_POST_DEAD notifiers are executed.
Reported-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
__cpufreq_remove_dev_finish() handles the kobject cleanup for a CPU going
offline. But because we destroy the kobject towards the end of the CPU offline
phase, there are certain race windows where a task can try to write to a
cpufreq sysfs file (eg: using store_scaling_max_freq()) while we are taking
that CPU offline, and this can bump up the kobject refcount, which in turn might
hinder the CPU offline task from running to completion. (It can also cause
other more serious problems such as trying to acquire a destroyed timer-mutex
etc., depending on the exact stage of the cleanup at which the task managed to
take a new refcount).
To fix the race window, we will need to synchronize those store_*() call-sites
with CPU hotplug, using get_online_cpus()/put_online_cpus(). However, that
in turn can cause a total deadlock because it can end up waiting for the
CPU offline task to complete, with incremented refcount!
Write to sysfs CPU offline task
-------------- ----------------
kobj_refcnt++
Acquire cpu_hotplug.lock
get_online_cpus();
Wait for kobj_refcnt to drop to zero
**DEADLOCK**
A simple way to avoid this problem is to perform the kobject cleanup in the
CPU offline path, with the cpu_hotplug.lock *released*. That is, we can
perform the wait-for-kobj-refcnt-to-drop as well as the subsequent cleanup
in the CPU_POST_DEAD stage of CPU offline, which is run with cpu_hotplug.lock
released. Doing this helps us avoid deadlocks due to holding kobject refcounts
and waiting on each other on the cpu_hotplug.lock.
(Note: We can't move all of the cpufreq CPU offline steps to the
CPU_POST_DEAD stage, because certain things such as stopping the governors
have to be done before the outgoing CPU is marked offline. So retain those
parts in the CPU_DOWN_PREPARE stage itself).
Reported-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
During CPU offline, the cpufreq core invokes __cpufreq_remove_dev()
to perform work such as stopping the cpufreq governor, clearing the
CPU from the policy structure etc, and finally cleaning up the
kobject.
There are certain subtle issues related to the kobject cleanup, and
it would be much easier to deal with them if we separate that part
from the rest of the cleanup-work in the CPU offline phase. So split
the __cpufreq_remove_dev() function into 2 parts: one that handles
the kobject cleanup, and the other that handles the rest of the work.
Reported-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The time spent by a CPU under a given frequency is stored in jiffies unit
in the cpu var cpufreq_stats_table->time_in_state[i], i being the index of
the frequency.
This is what is displayed in the following file on the right column:
cat /sys/devices/system/cpu/cpuX/cpufreq/stats/time_in_state
2301000 19835820
2300000 3172
[...]
Now cpufreq converts this jiffies unit delta to clock_t before returning it
to the user as in the above file. And that conversion is achieved using the API
cputime64_to_clock_t().
Although it accidentally works on traditional tick based cputime accounting, where
cputime_t maps directly to jiffies, it doesn't work with other types of cputime
accounting such as CONFIG_VIRT_CPU_ACCOUNTING_* where cputime_t can map to nsecs
or any granularity preffered by the architecture.
For example we get a buggy zero delta on full dyntick configurations:
cat /sys/devices/system/cpu/cpuX/cpufreq/stats/time_in_state
2301000 0
2300000 0
[...]
Fix this with using the proper jiffies_64_t to clock_t conversion.
Reported-and-tested-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
