Commit Graph

254141 Commits

Author SHA1 Message Date
Al Viro
6b419951f1 coda_ioctl_permission() is safe in RCU mode
return (mask & MAY_EXEC) ? -EACCES : 0; is non-blocking...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-06-20 10:44:19 -04:00
Al Viro
ec12781f19 cifs_permission() doesn't need to bail out in RCU mode
nothing potentially blocking except generic_permission(), which
will DTRT

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-06-20 10:44:07 -04:00
Al Viro
1712c20dae bad_inode_permission() is safe from RCU mode
return -EIO; is *not* a blocking operation, thank you very much.
Nick, what the hell have you been smoking?

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-06-20 10:44:00 -04:00
Dan Carpenter
185bf87393 ubifs: dereferencing an ERR_PTR in ubifs_mount()
d251ed271d "ubifs: fix sget races" left out the goto from this
error path so the static checkers complain that we're dereferencing
"sb" when it's an ERR_PTR.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-06-20 10:42:34 -04:00
J. Bruce Fields
105f462210 nfsd4: fix break_lease flags on nfsd open
Thanks to Casey Bodley for pointing out that on a read open we pass 0,
instead of O_RDONLY, to break_lease, with the result that a read open is
treated like a write open for the purposes of lease breaking!

Reported-by: Casey Bodley <cbodley@citi.umich.edu>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-06-20 10:38:01 -04:00
David Henningsson
6f2e810ad5 ALSA: HDA: Remove quirk for an HP device
The reporter, who is running kernel 2.6.38, reports that
he needs to set model=auto for the headphone output to work
correctly.

BugLink: http://bugs.launchpad.net/bugs/761022
Cc: stable@kernel.org (v2.6.38+)
Reported-by: Jo
Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2011-06-20 16:32:50 +02:00
Namhyung Kim
155d109b5f block: add REQ_SECURE to REQ_COMMON_MASK
Add REQ_SECURE flag to REQ_COMMON_MASK so that
init_request_from_bio() can pass it to @req->cmd_flags.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@kernel.org # 2.6.36 and newer
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-06-20 13:23:14 +02:00
Dave Airlie
4ee1c57fca drm/nouveau: drop leftover debugging
this printk isn't really useful, just drop it for now.

Signed-off-by: Dave Airlie <airlied@redhat.com>
2011-06-20 15:27:18 +10:00
Dave Airlie
ca295e50c2 Merge branch 'drm-nouveau-fixes' of git://anongit.freedesktop.org/git/nouveau/linux-2.6 into drm-fixes
* 'drm-nouveau-fixes' of git://anongit.freedesktop.org/git/nouveau/linux-2.6:
  drm/nouveau: fix assumption that semaphore dmaobj is valid in x-chan sync
  drm/nv50/disp: fix gamma with page flipping overlay turned on
  drm/nouveau/pm: Prevent overflow in nouveau_perf_init()
  drm/nouveau: fix big-endian switch
2011-06-20 12:02:38 +10:00
Dave Airlie
682f1a54a0 drm/radeon: avoid warnings from r600/eg irq handlers on powered off card.
Since we were calling the wptr function before checking if the IH was
even enabled, or the GPU wasn't shutdown, we'd get spam in the logs when
the GPU readback 0xffffffff. This reorders things so we return early
in the no IH and GPU shutdown cases.

Reported-and-tested-by: ManDay on #radeon
Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2011-06-20 12:01:43 +10:00
Alex Deucher
74d074eecb drm/radeon/kms: add missing param for dce3.2 DP transmitter setup
This is used during phy init to set up the phy for DP.  This may
fix DP problems on DCE3.2 cards.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2011-06-20 09:53:02 +10:00
Alex Deucher
8323fa6ba3 drm/radeon/kms/atom: fix duallink on some early DCE3.2 cards
Certain revisions of the vbios on DCE3.2 cards have a bug
in the transmitter control table which prevents duallink from
being enabled properly on some cards.  The action switch statement
jumps to the wrong offset for the OUTPUT_ENABLE action.  The fix
is to use the ENABLE action rather than the OUTPUT_ENABLE action
on the affected cards.  In fixed version of the vbios, both
actions jump to the same offset, so the change should be safe.

Reported-and-tested-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
2011-06-20 09:52:24 +10:00
Eric Dumazet
44da29d26b sgi-xp: fix a use after free
Its illegal to dereference skb after dev_kfree_skb(skb)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Robin Holt <holt@sgi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-06-19 16:28:03 -07:00
Eric Dumazet
658924dc9a hp100: fix an skb->len race
As soon as skb is given to hardware and spinlock released, TX completion
can free skb under us. Therefore, we should update netdev stats before
spinlock release.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-06-19 16:28:02 -07:00
David S. Miller
00ce2d5614 Merge branch 'davem.r8169' of git://git.kernel.org/pub/scm/linux/kernel/git/romieu/netdev-2.6 2011-06-19 16:26:46 -07:00
WANG Cong
cefa9993f1 netpoll: copy dev name of slaves to struct netpoll
Otherwise we will not see the name of the slave dev in error
message:

[  388.469446] (null):  doesn't support polling, aborting.

Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-06-19 16:13:01 -07:00
Boaz Harrosh
df18d127f4 pnfs-obj: No longer needed to take an extra ref at add_device
Andy's last device_cache patches, already take an extra
reference on the newly inserted device_id. So we can remove it
from obj-io.

Without this patch the device_ids are leaked.

Andy's patches are not in Linus tree yet. So I'm not sure if they are
scheduled for this Kernel or the next. This patch should be added as
part of these.

CC: Andy Adamson <andros@netapp.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-06-19 14:49:51 -04:00
Zachary Amsden
de2d1a524e KVM: Fix register corruption in pvclock_scale_delta
The 128-bit multiply in pvclock.h was missing an output constraint for
EDX which caused a register corruption to appear.  Thanks to Ulrich for
diagnosing the EDX corruption and Avi for providing this fix.

Signed-off-by: Zachary Amsden <zamsden@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-06-19 19:23:14 +03:00
Steve
a0a8eaba16 KVM: MMU: fix opposite condition in mapping_level_dirty_bitmap
The condition is opposite, it always maps huge page for the dirty tracked page

Reported-by: Steve <stefan.bosak@gmail.com>
Signed-off-by: Steve <stefan.bosak@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-06-19 19:23:13 +03:00
Marcelo Tosatti
5233dd51ec KVM: VMX: do not overwrite uptodate vcpu->arch.cr3 on KVM_SET_SREGS
Only decache guest CR3 value if vcpu->arch.cr3 is stale.
Fixes loadvm with live guest.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Tested-by: Markus Schade <markus.schade@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-06-19 19:23:13 +03:00
Borislav Petkov
b72336355b KVM: MMU: Fix build warnings in walk_addr_generic()
On 3.0-rc1 I get

In file included from arch/x86/kvm/mmu.c:2856:
arch/x86/kvm/paging_tmpl.h: In function ‘paging32_walk_addr_generic’:
arch/x86/kvm/paging_tmpl.h:124: warning: ‘ptep_user’ may be used uninitialized in this function
In file included from arch/x86/kvm/mmu.c:2852:
arch/x86/kvm/paging_tmpl.h: In function ‘paging64_walk_addr_generic’:
arch/x86/kvm/paging_tmpl.h:124: warning: ‘ptep_user’ may be used uninitialized in this function

caused by 6e2ca7d180. According to Takuya
Yoshikawa, ptep_user won't be used uninitialized so shut up gcc.

Cc: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Link: http://lkml.kernel.org/r/20110530094604.GC21833@liondog.tnic
Signed-off-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-06-19 19:23:13 +03:00
Linus Torvalds
8816ead9d8 Merge branches 'perf-urgent-for-linus', 'sched-urgent-for-linus', 'timers-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  tools/perf: Fix static build of perf tool
  tracing: Fix regression in printk_formats file

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  generic-ipi: Fix kexec boot crash by initializing call_single_queue before enabling interrupts

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  clocksource: Make watchdog robust vs. interruption
  timerfd: Fix wakeup of processes when timer is cancelled on clock change

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, MAINTAINERS: Add x86 MCE people
  x86, efi: Do not reserve boot services regions within reserved areas
2011-06-19 09:00:18 -07:00
Linus Torvalds
357ed6b1a1 Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  rcu: Move RCU_BOOST #ifdefs to header file
  rcu: use softirq instead of kthreads except when RCU_BOOST=y
  rcu: Use softirq to address performance regression
  rcu: Simplify curing of load woes
2011-06-19 08:56:56 -07:00
Linus Torvalds
de505e709f Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging:
  hwmon: (s3c) Initialize sysfs attributes
  hwmon: (ibmpex) Initialize sysfs attributes
  hwmon: (ibmaem) Initialize sysfs attributes
  hwmon: (asus_atk0110) Consolidate sysfs attribute initialization
  hwmon: (coretemp) Drop unused struct members
2011-06-18 20:33:31 -07:00
Manoj Iyer
be98ca652f mmc: Add PCI fixup quirks for Ricoh 1180:e823 reader
Signed-off-by: Manoj Iyer <manoj.iyer@canonical.com>
Cc: <stable@kernel.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
2011-06-18 22:18:18 -04:00
Guennadi Liakhovetski
742a0c7cae mmc: sdhi: fix module unloading
MMC host drivers must be able to process interrupts during
mmc_remove_host().

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>
2011-06-18 22:18:06 -04:00
Wanlong Gao
b9c350a0a9 mmc: of_mmc_spi: add NO_IRQ define to of_mmc_spi.c
Provide a dummy value of NO_IRQ for architectures that don't support
it (such as MIPS).  Fixes the build error for MIPS.

Signed-off-by: Wanlong Gao <wanlong.gao@gmail.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Chris Ball <cjb@laptop.org>
2011-06-18 22:18:00 -04:00
Chris Ball
c44048dea2 mmc: vub300: fix null dereferences in error handling
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
2011-06-18 22:17:51 -04:00
Ingo Molnar
c1f5c54b57 x86, MAINTAINERS: Add x86 MCE people
Announce the new x86 MCE infrastructure maintainers.

Acked-by: Borislav Petkov <bp@amd64.org>
Acked-by: Tony Luck <tony.luck@intel.com>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/n/tip-8hs7yob6wib4vblmrmbpbav4@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-06-18 22:51:13 +02:00
Maarten Lankhorst
7d68dc3f10 x86, efi: Do not reserve boot services regions within reserved areas
Commit 916f676f8d started reserving boot service code since some systems
require you to keep that code around until SetVirtualAddressMap is called.

However, in some cases those areas will overlap with reserved regions.
The proper medium-term fix is to fix the bootloader to prevent the
conflicts from occurring by moving the kernel to a better position,
but the kernel should check for this possibility, and only reserve regions
which can be reserved.

Signed-off-by: Maarten Lankhorst <m.b.lankhorst@gmail.com>
Link: http://lkml.kernel.org/r/4DF7A005.1050407@gmail.com
Acked-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-06-18 22:48:49 +02:00
Eric Dumazet
9aa3c94ce5 ipv4: fix multicast losses
Knut Tidemann found that first packet of a multicast flow was not
correctly received, and bisected the regression to commit b23dd4fe42
(Make output route lookup return rtable directly.)

Special thanks to Knut, who provided a very nice bug report, including
sample programs to demonstrate the bug.

Reported-and-bisectedby: Knut Tidemann <knut.andre.tidemann@jotron.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-06-18 11:59:18 -07:00
Linus Torvalds
c11760c6d8 isofs: fix bh leak in isofs_fill_super() error case
In isofs_fill_super(), when an iso_primary_descriptor is found, it is
kept in pri_bh.  The error cases don't properly release it.  Fix it.

Reported-and-tested-by: 김원석 <stanley.will.kim@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-18 07:25:42 -07:00
Magnus Damm
cca23d0b53 Input: sh_keysc - 8x8 MODE_6 fix
According to the data sheet for G4, AP4 and AG5 KEYSC MODE_6 is 8x8 keys.
Bump up MAXKEYS to 64 too.

Signed-off-by: Magnus Damm <damm@opensource.se>
Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2011-06-18 02:55:01 -07:00
Janusz Krzysztofik
b27af563be Input: omap-keypad - add missing input_sync()
Otherwise the updated evdev driver (commit cdda911c34,
"Input: evdev - only signal polls on full packets") no longer works on
top of omap-keypad.

Tested on Amstrad Delta.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2011-06-18 02:54:42 -07:00
Dmitry Torokhov
da40b0b6b4 Input: evdev - try to wake up readers only if we have full packet
We should only wake waiters on the event device when we actually post
an EV_SYN/SYN_REPORT to the queue. Otherwise we end up making waiting
threads runnable only to go right back to sleep because the device
still isn't readable.

Reported-by: Jeffrey Brown <jeffbrown@android.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2011-06-18 02:54:02 -07:00
Guenter Roeck
b1e698db09 hwmon: (s3c) Initialize sysfs attributes
Initialize dynamically allocated sysfs attributes before device_create_file()
call to suppress lockdep_init_map() warning if lockdep debugging is enabled.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Cc: stable@kernel.org # 2.6.34+
2011-06-17 23:22:27 -07:00
Guenter Roeck
fb794e0f71 hwmon: (ibmpex) Initialize sysfs attributes
Initialize dynamically allocated sysfs attributes before device_create_file()
call to suppress lockdep_init_map() warning if lockdep debugging is enabled.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Cc: stable@kernel.org # 2.6.34+
2011-06-17 23:22:27 -07:00
Guenter Roeck
3cdb2052a6 hwmon: (ibmaem) Initialize sysfs attributes
Initialize dynamically allocated sysfs attributes before device_create_file()
call to suppress lockdep_init_map() warning if lockdep debugging is enabled.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Cc: stable@kernel.org # 2.6.34+
2011-06-17 23:22:26 -07:00
Guenter Roeck
9a2d55be11 hwmon: (asus_atk0110) Consolidate sysfs attribute initialization
Call sysfs_attr_init() from atk_init_attribute() to handle sysfs attribute
initialization in a single function.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: Luca Tettamanti <kronos.it@gmail.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
2011-06-17 23:22:26 -07:00
Jean Delvare
808b4e639e hwmon: (coretemp) Drop unused struct members
pdev_entry.cpu and pdev_entry.cpu_core_id aren't used anywhere in the
driver code so we can drop these struct members.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
2011-06-17 23:22:26 -07:00
Ben Skeggs
b16a5a18ff drm/nouveau: fix assumption that semaphore dmaobj is valid in x-chan sync
The DDX modifies DMA_SEMAPHORE on nv50 in order to implement sync-to-vblank,
things will go very wrong for cross-channel sync after this.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2011-06-18 14:56:24 +10:00
Ben Skeggs
f66b3d5540 drm/nv50/disp: fix gamma with page flipping overlay turned on
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2011-06-18 14:38:45 +10:00
Emil Velikov
2905544073 drm/nouveau/pm: Prevent overflow in nouveau_perf_init()
While parsing the perf table, there is no check if
the num of entries read from the vbios is less than
the currently allocated number.

In case of a buggy vbios this will cause overwriting
of kernel memory, causing aditional problems.

Add a simple check in order to prevent the case

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2011-06-18 14:38:38 +10:00
Ben Skeggs
0897554cdd drm/nouveau: fix big-endian switch
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2011-06-18 14:38:27 +10:00
Linus Torvalds
a6c0a39262 Merge branch 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6
* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
  drm/i915: Fix gen6 (SNB) missed BLT ring interrupts.
2011-06-17 21:15:11 -07:00
Linus Torvalds
2f48802e43 Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
  [CPUFREQ] powernow-k8: Don't try to transition if the pstate is incorrect
  [CPUFREQ] powernow-k8: Don't notify of successful transition if we failed (vid case).
  [CPUFREQ] Don't set stat->last_index to -1 if the pol->cur has incorrect value.
2011-06-17 21:13:43 -07:00
Linus Torvalds
95559f2ca1 Merge branch 'anon_vma-locking'
* anon_vma-locking:
  mm: avoid anon_vma_chain allocation under anon_vma lock
  mm: avoid repeated anon_vma lock/unlock sequences in unlink_anon_vmas()
  mm: avoid repeated anon_vma lock/unlock sequences in anon_vma_clone()
2011-06-17 21:01:21 -07:00
Linus Torvalds
dd34739c03 mm: avoid anon_vma_chain allocation under anon_vma lock
Hugh Dickins points out that lockdep (correctly) spots a potential
deadlock on the anon_vma lock, because we now do a GFP_KERNEL allocation
of anon_vma_chain while doing anon_vma_clone().  The problem is that
page reclaim will want to take the anon_vma lock of any anonymous pages
that it will try to reclaim.

So re-organize the code in anon_vma_clone() slightly: first do just a
GFP_NOWAIT allocation, which will usually work fine.  But if that fails,
let's just drop the lock and re-do the allocation, now with GFP_KERNEL.

End result: not only do we avoid the locking problem, this also ends up
getting better concurrency in case the allocation does need to block.
Tim Chen reports that with all these anon_vma locking tweaks, we're now
almost back up to the spinlock performance.

Reported-and-tested-by: Hugh Dickins <hughd@google.com>
Tested-by: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-17 19:24:11 -07:00
Peter Zijlstra
eee2acbae9 mm: avoid repeated anon_vma lock/unlock sequences in unlink_anon_vmas()
This matches the anon_vma_clone() case, and uses the same lock helper
functions.  Because of the need to potentially release the anon_vma's,
it's a bit more complex, though.

We traverse the 'vma->anon_vma_chain' in two phases: the first loop gets
the anon_vma lock (with the helper function that only takes the lock
once for the whole loop), and removes any entries that don't need any
more processing.

The second phase just traverses the remaining list entries (without
holding the anon_vma lock), and does any actual freeing of the
anon_vma's that is required.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Hugh Dickins <hughd@google.com>
Tested-by: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-17 19:23:52 -07:00
Linus Torvalds
bb4aa39676 mm: avoid repeated anon_vma lock/unlock sequences in anon_vma_clone()
In anon_vma_clone() we traverse the vma->anon_vma_chain of the source
vma, locking the anon_vma for each entry.

But they are all going to have the same root entry, which means that
we're locking and unlocking the same lock over and over again.  Which is
expensive in locked operations, but can get _really_ expensive when that
root entry sees any kind of lock contention.

In fact, Tim Chen reports a big performance regression due to this: when
we switched to use a mutex instead of a spinlock, the contention case
gets much worse.

So to alleviate this all, this commit creates a small helper function
(lock_anon_vma_root()) that can be used to take the lock just once
rather than taking and releasing it over and over again.

We still have the same "take the lock and release" it behavior in the
exit path (in unlink_anon_vmas()), but that one is a bit harder to fix
since we're actually freeing the anon_vma entries as we go, and that
will touch the lock too.

Reported-and-tested-by: Tim Chen <tim.c.chen@linux.intel.com>
Tested-by: Hugh Dickins <hughd@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-17 19:20:49 -07:00