Commit Graph

687 Commits

Author SHA1 Message Date
Mel Gorman d26914d117 mm: optimize put_mems_allowed() usage
Since put_mems_allowed() is strictly optional, its a seqcount retry, we
don't need to evaluate the function if the allocation was in fact
successful, saving a smp_rmb some loads and comparisons on some relative
fast-paths.

Since the naming, get/put_mems_allowed() does suggest a mandatory
pairing, rename the interface, as suggested by Mel, to resemble the
seqcount interface.

This gives us: read_mems_allowed_begin() and read_mems_allowed_retry(),
where it is important to note that the return value of the latter call
is inverted from its previous incarnation.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:20:58 -07:00
Joonsoo Kim 80c3a9981a slub: fix high order page allocation problem with __GFP_NOFAIL
SLUB already try to allocate high order page with clearing __GFP_NOFAIL.
But, when allocating shadow page for kmemcheck, it missed clearing
the flag. This trigger WARN_ON_ONCE() reported by Christian Casteyde.

https://bugzilla.kernel.org/show_bug.cgi?id=65991
https://lkml.org/lkml/2013/12/3/764

This patch fix this situation by using same allocation flag as original
allocation.

Reported-by: Christian Casteyde <casteyde.christian@free.fr>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2014-03-27 14:27:34 +02:00
Steven Rostedt 1e4dd9461f slub: do not assert not having lock in removing freed partial
Vladimir reported the following issue:

Commit c65c1877bd ("slub: use lockdep_assert_held") requires
remove_partial() to be called with n->list_lock held, but free_partial()
called from kmem_cache_close() on cache destruction does not follow this
rule, leading to a warning:

  WARNING: CPU: 0 PID: 2787 at mm/slub.c:1536 __kmem_cache_shutdown+0x1b2/0x1f0()
  Modules linked in:
  CPU: 0 PID: 2787 Comm: modprobe Tainted: G        W    3.14.0-rc1-mm1+ #1
  Hardware name:
   0000000000000600 ffff88003ae1dde8 ffffffff816d9583 0000000000000600
   0000000000000000 ffff88003ae1de28 ffffffff8107c107 0000000000000000
   ffff880037ab2b00 ffff88007c240d30 ffffea0001ee5280 ffffea0001ee52a0
  Call Trace:
    __kmem_cache_shutdown+0x1b2/0x1f0
    kmem_cache_destroy+0x43/0xf0
    xfs_destroy_zones+0x103/0x110 [xfs]
    exit_xfs_fs+0x38/0x4e4 [xfs]
    SyS_delete_module+0x19a/0x1f0
    system_call_fastpath+0x16/0x1b

His solution was to add a spinlock in order to quiet lockdep.  Although
there would be no contention to adding the lock, that lock also requires
disabling of interrupts which will have a larger impact on the system.

Instead of adding a spinlock to a location where it is not needed for
lockdep, make a __remove_partial() function that does not test if the
list_lock is held, as no one should have it due to it being freed.

Also added a __add_partial() function that does not do the lock
validation either, as it is not needed for the creation of the cache.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Reported-by: Vladimir Davydov <vdavydov@parallels.com>
Suggested-by: David Rientjes <rientjes@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-02-10 16:01:42 -08:00
David Rientjes 255d0884f5 mm/slub.c: list_lock may not be held in some circumstances
Commit c65c1877bd ("slub: use lockdep_assert_held") incorrectly
required that add_full() and remove_full() hold n->list_lock.  The lock
is only taken when kmem_cache_debug(s), since that's the only time it
actually does anything.

Require that the lock only be taken under such a condition.

Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-02-10 16:01:41 -08:00
Linus Torvalds 7b383bef25 Merge branch 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
Pull SLAB changes from Pekka Enberg:
 "Random bug fixes that have accumulated in my inbox over the past few
  months"

* 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
  mm: Fix warning on make htmldocs caused by slab.c
  mm: slub: work around unneeded lockdep warning
  mm: sl[uo]b: fix misleading comments
  slub: Fix possible format string bug.
  slub: use lockdep_assert_held
  slub: Fix calculation of cpu slabs
  slab.h: remove duplicate kmalloc declaration and fix kernel-doc warnings
2014-02-02 11:30:08 -08:00
Dave Hansen 67b6c900dc mm: slub: work around unneeded lockdep warning
The slub code does some setup during early boot in
early_kmem_cache_node_alloc() with some local data.  There is no
possible way that another CPU can see this data, so the slub code
doesn't unnecessarily lock it.  However, some new lockdep asserts
check to make sure that add_partial() _always_ has the list_lock
held.

Just add the locking, even though it is technically unnecessary.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2014-01-31 13:41:26 +02:00
Dave Hansen a03208652d mm/slub.c: fix page->_count corruption (again)
Commit abca7c4965 ("mm: fix slab->page _count corruption when using
slub") notes that we can not _set_ a page->counters directly, except
when using a real double-cmpxchg.  Doing so can lose updates to
->_count.

That is an absolute rule:

        You may not *set* page->counters except via a cmpxchg.

Commit abca7c4965 fixed this for the folks who have the slub
cmpxchg_double code turned off at compile time, but it left the bad case
alone.  It can still be reached, and the same bug triggered in two
cases:

1. Turning on slub debugging at runtime, which is available on
   the distro kernels that I looked at.
2. On 64-bit CPUs with no CMPXCHG16B (some early AMD x86-64
   cpus, evidently)

There are at least 3 ways we could fix this:

1. Take all of the exising calls to cmpxchg_double_slab() and
   __cmpxchg_double_slab() and convert them to take an old, new
   and target 'struct page'.
2. Do (1), but with the newly-introduced 'slub_data'.
3. Do some magic inside the two cmpxchg...slab() functions to
   pull the counters out of new_counters and only set those
   fields in page->{inuse,frozen,objects}.

I've done (2) as well, but it's a bunch more code.  This patch is an
attempt at (3).  This was the most straightforward and foolproof way
that I could think to do this.

This would also technically allow us to get rid of the ugly

#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
       defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)

in 'struct page', but leaving it alone has the added benefit that
'counters' stays 'unsigned' instead of 'unsigned long', so all the
copies that the slub code does stay a bit smaller.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-30 16:56:56 -08:00
Dave Hansen a0132ac0f2 mm/slub.c: do not VM_BUG_ON_PAGE() for temporary on-stack pages
Commit 309381feae ("mm: dump page when hitting a VM_BUG_ON using
VM_BUG_ON_PAGE") added a bunch of VM_BUG_ON_PAGE() calls.

But, most of the ones in the slub code are for _temporary_ 'struct
page's which are declared on the stack and likely have lots of gunk in
them.  Dumping their contents out will just confuse folks looking at
bad_page() output.  Plus, if we try to page_to_pfn() on them or
soemthing, we'll probably oops anyway.

Turn them back in to VM_BUG_ON()s.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-29 16:22:40 -08:00
Sasha Levin 309381feae mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE
Most of the VM_BUG_ON assertions are performed on a page.  Usually, when
one of these assertions fails we'll get a BUG_ON with a call stack and
the registers.

I've recently noticed based on the requests to add a small piece of code
that dumps the page to various VM_BUG_ON sites that the page dump is
quite useful to people debugging issues in mm.

This patch adds a VM_BUG_ON_PAGE(cond, page) which beyond doing what
VM_BUG_ON() does, also dumps the page before executing the actual
BUG_ON.

[akpm@linux-foundation.org: fix up includes]
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-23 16:36:50 -08:00
Tetsuo Handa 26e4f20575 slub: Fix possible format string bug.
The "name" is determined at runtime and is parsed as format string.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2014-01-13 21:36:34 +02:00
Peter Zijlstra c65c1877bd slub: use lockdep_assert_held
Instead of using comments in an attempt at getting the locking right,
use proper assertions that actively warn you if you got it wrong.

Also add extra braces in a few sites to comply with coding-style.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2014-01-13 21:34:39 +02:00
Li Zefan 8afb1474db slub: Fix calculation of cpu slabs
/sys/kernel/slab/:t-0000048 # cat cpu_slabs
  231 N0=16 N1=215
  /sys/kernel/slab/:t-0000048 # cat slabs
  145 N0=36 N1=109

See, the number of slabs is smaller than that of cpu slabs.

The bug was introduced by commit 49e2258586
("slub: per cpu cache for partial pages").

We should use page->pages instead of page->pobjects when calculating
the number of cpu partial slabs. This also fixes the mapping of slabs
and nodes.

As there's no variable storing the number of total/active objects in
cpu partial slabs, and we don't have user interfaces requiring those
statistics, I just add WARN_ON for those cases.

Cc: <stable@vger.kernel.org> # 3.2+
Acked-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-12-29 13:44:45 +02:00
Linus Torvalds 24f971abbd Merge branch 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
Pull SLAB changes from Pekka Enberg:
 "The patches from Joonsoo Kim switch mm/slab.c to use 'struct page' for
  slab internals similar to mm/slub.c.  This reduces memory usage and
  improves performance:

    https://lkml.org/lkml/2013/10/16/155

  Rest of the changes are bug fixes from various people"

* 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux: (21 commits)
  mm, slub: fix the typo in mm/slub.c
  mm, slub: fix the typo in include/linux/slub_def.h
  slub: Handle NULL parameter in kmem_cache_flags
  slab: replace non-existing 'struct freelist *' with 'void *'
  slab: fix to calm down kmemleak warning
  slub: proper kmemleak tracking if CONFIG_SLUB_DEBUG disabled
  slab: rename slab_bufctl to slab_freelist
  slab: remove useless statement for checking pfmemalloc
  slab: use struct page for slab management
  slab: replace free and inuse in struct slab with newly introduced active
  slab: remove SLAB_LIMIT
  slab: remove kmem_bufctl_t
  slab: change the management method of free objects of the slab
  slab: use __GFP_COMP flag for allocating slab pages
  slab: use well-defined macro, virt_to_slab()
  slab: overloading the RCU head over the LRU for RCU free
  slab: remove cachep in struct slab_rcu
  slab: remove nodeid in struct slab
  slab: remove colouroff in struct slab
  slab: change return type of kmem_getpages() to struct page
  ...
2013-11-22 08:10:34 -08:00
Linus Torvalds 9073e1a804 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial tree updates from Jiri Kosina:
 "Usual earth-shaking, news-breaking, rocket science pile from
  trivial.git"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (23 commits)
  doc: usb: Fix typo in Documentation/usb/gadget_configs.txt
  doc: add missing files to timers/00-INDEX
  timekeeping: Fix some trivial typos in comments
  mm: Fix some trivial typos in comments
  irq: Fix some trivial typos in comments
  NUMA: fix typos in Kconfig help text
  mm: update 00-INDEX
  doc: Documentation/DMA-attributes.txt fix typo
  DRM: comment: `halve' -> `half'
  Docs: Kconfig: `devlopers' -> `developers'
  doc: typo on word accounting in kprobes.c in mutliple architectures
  treewide: fix "usefull" typo
  treewide: fix "distingush" typo
  mm/Kconfig: Grammar s/an/a/
  kexec: Typo s/the/then/
  Documentation/kvm: Update cpuid documentation for steal time and pv eoi
  treewide: Fix common typo in "identify"
  __page_to_pfn: Fix typo in comment
  Correct some typos for word frequency
  clk: fixed-factor: Fix a trivial typo
  ...
2013-11-15 16:47:22 -08:00
Qiang Huang 2ade4de871 memcg, kmem: rename cache_from_memcg to cache_from_memcg_idx
We can't see the relationship with memcg from the parameters,
so the name with memcg_idx would be more reasonable.

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 12:09:10 +09:00
Zhi Yong Wu 721ae22ae1 mm, slub: fix the typo in mm/slub.c
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-11-11 18:19:07 +02:00
Christoph Lameter c6f58d9b36 slub: Handle NULL parameter in kmem_cache_flags
Andreas Herrmann writes:

  When I've used slub_debug kernel option (e.g.
  "slub_debug=,skbuff_fclone_cache" or similar) on a debug session I've
  seen a panic like:

    Highbank #setenv bootargs console=ttyAMA0 root=/dev/sda2 kgdboc.kgdboc=ttyAMA0,115200 slub_debug=,kmalloc-4096 earlyprintk=ttyAMA0
    ...
    Unable to handle kernel NULL pointer dereference at virtual address 00000000
    pgd = c0004000
    [00000000] *pgd=00000000
    Internal error: Oops: 5 [#1] SMP ARM
    Modules linked in:
    CPU: 0 PID: 0 Comm: swapper Tainted: G        W    3.12.0-00048-gbe408cd #314
    task: c0898360 ti: c088a000 task.ti: c088a000
    PC is at strncmp+0x1c/0x84
    LR is at kmem_cache_flags.isra.46.part.47+0x44/0x60
    pc : [<c02c6da0>]    lr : [<c0110a3c>]    psr: 200001d3
    sp : c088bea8  ip : c088beb8  fp : c088beb4
    r10: 00000000  r9 : 413fc090  r8 : 00000001
    r7 : 00000000  r6 : c2984a08  r5 : c0966e78  r4 : 00000000
    r3 : 0000006b  r2 : 0000000c  r1 : 00000000  r0 : c2984a08
    Flags: nzCv  IRQs off  FIQs off  Mode SVC_32  ISA ARM  Segment kernel
    Control: 10c5387d  Table: 0000404a  DAC: 00000015
    Process swapper (pid: 0, stack limit = 0xc088a248)
    Stack: (0xc088bea8 to 0xc088c000)
    bea0:                   c088bed4 c088beb8 c0110a3c c02c6d90 c0966e78 00000040
    bec0: ef001f00 00000040 c088bf14 c088bed8 c0112070 c0110a04 00000005 c010fac8
    bee0: c088bf5c c088bef0 c010fac8 ef001f00 00000040 00000000 00000040 00000001
    bf00: 413fc090 00000000 c088bf34 c088bf18 c0839190 c0112040 00000000 ef001f00
    bf20: 00000000 00000000 c088bf54 c088bf38 c0839200 c083914c 00000006 c0961c4c
    bf40: c0961c28 00000000 c088bf7c c088bf58 c08392ac c08391c0 c08a2ed8 c0966e78
    bf60: c086b874 c08a3f50 c0961c28 00000001 c088bfb4 c088bf80 c083b258 c0839248
    bf80: 2f800000 0f000000 c08935b4 ffffffff c08cd400 ffffffff c08cd400 c0868408
    bfa0: c29849c0 00000000 c088bff4 c088bfb8 c0824974 c083b1e4 ffffffff ffffffff
    bfc0: c08245c0 00000000 00000000 c0868408 00000000 10c5387d c0892bcc c0868404
    bfe0: c0899440 0000406a 00000000 c088bff8 00008074 c0824824 00000000 00000000
    [<c02c6da0>] (strncmp+0x1c/0x84) from [<c0110a3c>] (kmem_cache_flags.isra.46.part.47+0x44/0x60)
    [<c0110a3c>] (kmem_cache_flags.isra.46.part.47+0x44/0x60) from [<c0112070>] (__kmem_cache_create+0x3c/0x410)
    [<c0112070>] (__kmem_cache_create+0x3c/0x410) from [<c0839190>] (create_boot_cache+0x50/0x74)
    [<c0839190>] (create_boot_cache+0x50/0x74) from [<c0839200>] (create_kmalloc_cache+0x4c/0x88)
    [<c0839200>] (create_kmalloc_cache+0x4c/0x88) from [<c08392ac>] (create_kmalloc_caches+0x70/0x114)
    [<c08392ac>] (create_kmalloc_caches+0x70/0x114) from [<c083b258>] (kmem_cache_init+0x80/0xe0)
    [<c083b258>] (kmem_cache_init+0x80/0xe0) from [<c0824974>] (start_kernel+0x15c/0x318)
    [<c0824974>] (start_kernel+0x15c/0x318) from [<00008074>] (0x8074)
    Code: e3520000 01a00002 089da800 e5d03000 (e5d1c000)
    ---[ end trace 1b75b31a2719ed1d ]---
    Kernel panic - not syncing: Fatal exception

  Problem is that slub_debug option is not parsed before
  create_boot_cache is called. Solve this by changing slub_debug to
  early_param.

  Kernels 3.11, 3.10 are also affected.  I am not sure about older
  kernels.

Christoph Lameter explains:

  kmem_cache_flags may be called with NULL parameter during early boot.
  Skip the test in that case.

Cc: stable@vger.kernel.org # 3.10 and 3.11
Reported-by: Andreas Herrmann <andreas.herrmann@calxeda.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-11-11 18:15:45 +02:00
Roman Bobniev d56791b38e slub: proper kmemleak tracking if CONFIG_SLUB_DEBUG disabled
Move all kmemleak calls into hook functions, and make it so
that all hooks (both inside and outside of #ifdef CONFIG_SLUB_DEBUG)
call the appropriate kmemleak routines.  This allows for kmemleak
to be configured independently of slub debug features.

It also fixes a bug where kmemleak was only partially enabled in some
configurations.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Roman Bobniev <Roman.Bobniev@sonymobile.com>
Signed-off-by: Tim Bird <tim.bird@sonymobile.com>
Signed-off-by: Pekka Enberg <penberg@iki.fi>
2013-10-24 20:25:10 +03:00
Xie XiuQi d175617436 mm: Fix some trivial typos in comments
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2013-10-18 14:49:53 +02:00
Linus Torvalds bff157b3ad Merge branch 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
Pull SLAB update from Pekka Enberg:
 "Nothing terribly exciting here apart from Christoph's kmalloc
  unification patches that brings sl[aou]b implementations closer to
  each other"

* 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
  slab: Use correct GFP_DMA constant
  slub: remove verify_mem_not_deleted()
  mm/sl[aou]b: Move kmallocXXX functions to common code
  mm, slab_common: add 'unlikely' to size check of kmalloc_slab()
  mm/slub.c: beautify code for removing redundancy 'break' statement.
  slub: Remove unnecessary page NULL check
  slub: don't use cpu partial pages on UP
  mm/slub: beautify code for 80 column limitation and tab alignment
  mm/slub: remove 'per_cpu' which is useless variable
2013-09-15 07:15:06 -04:00
Jingoo Han 3dbb95f789 mm: replace strict_strtoul() with kstrtoul()
The use of strict_strtoul() is not preferred, because strict_strtoul() is
obsolete.  Thus, kstrtoul() should be used.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:11 -07:00
Christoph Lameter 76b6f3d255 slub: remove verify_mem_not_deleted()
I do not see any user for this code in the tree.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-09-04 20:53:16 +03:00
Christoph Lameter f1b6eb6e6b mm/sl[aou]b: Move kmallocXXX functions to common code
The kmalloc* functions of all slab allcoators are similar now so
lets move them into slab.h. This requires some function naming changes
in slob.

As a results of this patch there is a common set of functions for
all allocators. Also means that kmalloc_large() is now available
in general to perform large order allocations that go directly
via the page allocator. kmalloc_large() can be substituted if
kmalloc() throws warnings because of too large allocations.

kmalloc_large() has exactly the same semantics as kmalloc but
can only used for allocations > PAGE_SIZE.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-09-04 20:51:33 +03:00
Chen Gang 68f06650ea mm/slub.c: beautify code for removing redundancy 'break' statement.
Remove redundancy 'break' statement.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-08-13 09:21:46 +03:00
Libin ac6434e6b8 slub: Remove unnecessary page NULL check
In commit 4d7868e6(slub: Do not dereference NULL pointer in node_match)
had added check for page NULL in node_match.  Thus, it is not needed
to check it before node_match, remove it.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Libin <huawei.libin@huawei.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-08-13 09:21:46 +03:00
Linus Torvalds 370905069c Revert "slub: do not put a slab to cpu partial list when cpu_partial is 0"
This reverts commit 318df36e57.

This commit caused Steven Rostedt's hackbench runs to run out of memory
due to a leak.  As noted by Joonsoo Kim, it is buggy in the following
scenario:

 "I guess, you may set 0 to all kmem caches's cpu_partial via sysfs,
  doesn't it?

  In this case, memory leak is possible in following case.  Code flow of
  possible leak is follwing case.

   * in __slab_free()
   1. (!new.inuse || !prior) && !was_frozen
   2. !kmem_cache_debug && !prior
   3. new.frozen = 1
   4. after cmpxchg_double_slab, run the (!n) case with new.frozen=1
   5. with this patch, put_cpu_partial() doesn't do anything,
      because this cache's cpu_partial is 0
   6. return

  In step 5, leak occur"

And Steven does indeed have cpu_partial set to 0 due to RT testing.

Joonsoo is cooking up a patch, but everybody agrees that reverting this
for now is the right thing to do.

Reported-and-bisected-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-08-08 09:06:37 -07:00
Chen Gang d0e0ac9772 mm/slub: beautify code for 80 column limitation and tab alignment
Be sure of 80 column limitation for both code and comments.

Correct tab alignment for 'if-else' statement.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-07-17 10:11:57 +03:00
Chen Gang e35e1a9744 mm/slub: remove 'per_cpu' which is useless variable
Remove 'per_cpu', since it is useless now after the patch: "205ab99
slub: Update statistics handling for variable order slabs". And the
partial list is handled in the same way as the per cpu slab.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-07-15 12:37:55 +03:00
Paul Gortmaker 0db0628d90 kernel: delete __cpuinit usage from all core kernel files
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

This removes all the uses of the __cpuinit macros from C files in
the core kernel directories (kernel, init, lib, mm, and include)
that don't really have a specific maintainer.

[1] https://lkml.org/lkml/2013/5/20/589

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2013-07-14 19:36:59 -04:00
Linus Torvalds 54be820019 Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
Pull slab update from Pekka Enberg:
 "Highlights:

  - Fix for boot-time problems on some architectures due to
    init_lock_keys() not respecting kmalloc_caches boundaries
    (Christoph Lameter)

  - CONFIG_SLUB_CPU_PARTIAL requested by RT folks (Joonsoo Kim)

  - Fix for excessive slab freelist draining (Wanpeng Li)

  - SLUB and SLOB cleanups and fixes (various people)"

I ended up editing the branch, and this avoids two commits at the end
that were immediately reverted, and I instead just applied the oneliner
fix in between myself.

* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
  slub: Check for page NULL before doing the node_match check
  mm/slab: Give s_next and s_stop slab-specific names
  slob: Check for NULL pointer before calling ctor()
  slub: Make cpu partial slab support configurable
  slab: add kmalloc() to kernel API documentation
  slab: fix init_lock_keys
  slob: use DIV_ROUND_UP where possible
  slub: do not put a slab to cpu partial list when cpu_partial is 0
  mm/slub: Use node_nr_slabs and node_nr_objs in get_slabinfo
  mm/slub: Drop unnecessary nr_partials
  mm/slab: Fix /proc/slabinfo unwriteable for slab
  mm/slab: Sharing s_next and s_stop between slab and slub
  mm/slab: Fix drain freelist excessively
  slob: Rework #ifdeffery in slab.h
  mm, slab: moved kmem_cache_alloc_node comment to correct place
2013-07-14 15:14:29 -07:00
Steven Rostedt c25f195e82 slub: Check for page NULL before doing the node_match check
In the -rt kernel (mrg), we hit the following dump:

BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: [<ffffffff811573f1>] kmem_cache_alloc_node+0x51/0x180
PGD a2d39067 PUD b1641067 PMD 0
Oops: 0000 [#1] PREEMPT SMP
Modules linked in: sunrpc cpufreq_ondemand ipv6 tg3 joydev sg serio_raw pcspkr k8temp amd64_edac_mod edac_core i2c_piix4 e100 mii shpchp ext4 mbcache jbd2 sd_mod crc_t10dif sr_mod cdrom sata_svw ata_generic pata_acpi pata_serverworks radeon ttm drm_kms_helper drm hwmon i2c_algo_bit i2c_core dm_mirror dm_region_hash dm_log dm_mod
CPU 3
Pid: 20878, comm: hackbench Not tainted 3.6.11-rt25.14.el6rt.x86_64 #1 empty empty/Tyan Transport GT24-B3992
RIP: 0010:[<ffffffff811573f1>]  [<ffffffff811573f1>] kmem_cache_alloc_node+0x51/0x180
RSP: 0018:ffff8800a9b17d70  EFLAGS: 00010213
RAX: 0000000000000000 RBX: 0000000001200011 RCX: ffff8800a06d8000
RDX: 0000000004d92a03 RSI: 00000000000000d0 RDI: ffff88013b805500
RBP: ffff8800a9b17dc0 R08: ffff88023fd14d10 R09: ffffffff81041cbd
R10: 00007f4e3f06e9d0 R11: 0000000000000246 R12: ffff88013b805500
R13: ffff8801ff46af40 R14: 0000000000000001 R15: 0000000000000000
FS:  00007f4e3f06e700(0000) GS:ffff88023fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000000 CR3: 00000000a2d3a000 CR4: 00000000000007e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process hackbench (pid: 20878, threadinfo ffff8800a9b16000, task ffff8800a06d8000)
Stack:
 ffff8800a9b17da0 ffffffff81202e08 ffff8800a9b17de0 000000d001200011
 0000000001200011 0000000001200011 0000000000000000 0000000000000000
 00007f4e3f06e9d0 0000000000000000 ffff8800a9b17e60 ffffffff81041cbd
Call Trace:
 [<ffffffff81202e08>] ? current_has_perm+0x68/0x80
 [<ffffffff81041cbd>] copy_process+0xdd/0x15b0
 [<ffffffff810a2125>] ? rt_up_read+0x25/0x30
 [<ffffffff8104369a>] do_fork+0x5a/0x360
 [<ffffffff8107c66b>] ? migrate_enable+0xeb/0x220
 [<ffffffff8100b068>] sys_clone+0x28/0x30
 [<ffffffff81527423>] stub_clone+0x13/0x20
 [<ffffffff81527152>] ? system_call_fastpath+0x16/0x1b
Code: 89 fc 89 75 cc 41 89 d6 4d 8b 04 24 65 4c 03 04 25 48 ae 00 00 49 8b 50 08 4d 8b 28 49 8b 40 10 4d 85 ed 74 12 41 83 fe ff 74 27 <48> 8b 00 48 c1 e8 3a 41 39 c6 74 1b 8b 75 cc 4c 89 c9 44 89 f2
RIP  [<ffffffff811573f1>] kmem_cache_alloc_node+0x51/0x180
 RSP <ffff8800a9b17d70>
CR2: 0000000000000000
---[ end trace 0000000000000002 ]---

Now, this uses SLUB pretty much unmodified, but as it is the -rt kernel
with CONFIG_PREEMPT_RT set, spinlocks are mutexes, although they do
disable migration. But the SLUB code is relatively lockless, and the
spin_locks there are raw_spin_locks (not converted to mutexes), thus I
believe this bug can happen in mainline without -rt features. The -rt
patch is just good at triggering mainline bugs ;-)

Anyway, looking at where this crashed, it seems that the page variable
can be NULL when passed to the node_match() function (which does not
check if it is NULL). When this happens we get the above panic.

As page is only used in slab_alloc() to check if the node matches, if
it's NULL I'm assuming that we can say it doesn't and call the
__slab_alloc() code. Is this a correct assumption?

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-14 15:13:16 -07:00
Joonsoo Kim 345c905d13 slub: Make cpu partial slab support configurable
CPU partial support can introduce level of indeterminism that is not
wanted in certain context (like a realtime kernel). Make it
configurable.

This patch is based on Christoph Lameter's "slub: Make cpu partial slab
support configurable V2".

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-07-07 19:09:56 +03:00
Joonsoo Kim 318df36e57 slub: do not put a slab to cpu partial list when cpu_partial is 0
In free path, we don't check number of cpu_partial, so one slab can
be linked in cpu partial list even if cpu_partial is 0. To prevent this,
we should check number of cpu_partial in put_cpu_partial().

Acked-by: Christoph Lameeter <cl@linux.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-07-07 18:46:30 +03:00
Wanpeng Li c17fd13ec0 mm/slub: Use node_nr_slabs and node_nr_objs in get_slabinfo
Use existing interface node_nr_slabs and node_nr_objs to get
nr_slabs and nr_objs.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-07-07 18:37:48 +03:00
Wanpeng Li a446336454 mm/slub: Drop unnecessary nr_partials
This patch remove unused nr_partials variable.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-07-07 18:37:48 +03:00
Linus Torvalds 0f47c9423c Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
Pull slab changes from Pekka Enberg:
 "The bulk of the changes are more slab unification from Christoph.

  There's also few fixes from Aaron, Glauber, and Joonsoo thrown into
  the mix."

* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux: (24 commits)
  mm, slab_common: Fix bootstrap creation of kmalloc caches
  slab: Return NULL for oversized allocations
  mm: slab: Verify the nodeid passed to ____cache_alloc_node
  slub: tid must be retrieved from the percpu area of the current processor
  slub: Do not dereference NULL pointer in node_match
  slub: add 'likely' macro to inc_slabs_node()
  slub: correct to calculate num of acquired objects in get_partial_node()
  slub: correctly bootstrap boot caches
  mm/sl[au]b: correct allocation type check in kmalloc_slab()
  slab: Fixup CONFIG_PAGE_ALLOC/DEBUG_SLAB_LEAK sections
  slab: Handle ARCH_DMA_MINALIGN correctly
  slab: Common definition for kmem_cache_node
  slab: Rename list3/l3 to node
  slab: Common Kmalloc cache determination
  stat: Use size_t for sizes instead of unsigned
  slab: Common function to create the kmalloc array
  slab: Common definition for the array of kmalloc caches
  slab: Common constants for kmalloc boundaries
  slab: Rename nodelists to node
  slab: Common name for the per node structures
  ...
2013-05-07 08:42:20 -07:00
Pekka Enberg 69df2ac128 Merge branch 'slab/next' into slab/for-linus 2013-05-07 09:19:47 +03:00
Andrew Morton 3ac38faa1f mm/slub.c: use register_hotmemory_notifier()
Squishes a statement-with-no-effect warning, removes some ifdefs and
shrinks .text by 2 bytes.

Note that this code fails to check for blocking_notifier_chain_register()
failures.

Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:36 -07:00
Christoph Lameter 7cccd80b43 slub: tid must be retrieved from the percpu area of the current processor
As Steven Rostedt has pointer out: rescheduling could occur on a
different processor after the determination of the per cpu pointer and
before the tid is retrieved. This could result in allocation from the
wrong node in slab_alloc().

The effect is much more severe in slab_free() where we could free to the
freelist of the wrong page.

The window for something like that occurring is pretty small but it is
possible.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-04-05 14:23:06 +03:00
Christoph Lameter 4d7868e647 slub: Do not dereference NULL pointer in node_match
The variables accessed in slab_alloc are volatile and therefore
the page pointer passed to node_match can be NULL. The processing
of data in slab_alloc is tentative until either the cmpxhchg
succeeds or the __slab_alloc slowpath is invoked. Both are
able to perform the same allocation from the freelist.

Check for the NULL pointer in node_match.

A false positive will lead to a retry of the loop in __slab_alloc.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-04-05 14:23:05 +03:00
Joonsoo Kim 338b264229 slub: add 'likely' macro to inc_slabs_node()
After boot phase, 'n' always exist.
So add 'likely' macro for helping compiler.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-04-02 09:42:17 +03:00
Joonsoo Kim 633b076464 slub: correct to calculate num of acquired objects in get_partial_node()
There is a subtle bug when calculating a number of acquired objects.

Currently, we calculate "available = page->objects - page->inuse",
after acquire_slab() is called in get_partial_node().

In acquire_slab() with mode = 1, we always set new.inuse = page->objects.
So,

	acquire_slab(s, n, page, object == NULL);

	if (!object) {
		c->page = page;
		stat(s, ALLOC_FROM_PARTIAL);
		object = t;
		available = page->objects - page->inuse;

		!!! availabe is always 0 !!!
	...

Therfore, "available > s->cpu_partial / 2" is always false and
we always go to second iteration.
This patch correct this problem.

After that, we don't need return value of put_cpu_partial().
So remove it.

Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-04-02 09:42:10 +03:00
Glauber Costa 7d557b3cb6 slub: correctly bootstrap boot caches
After we create a boot cache, we may allocate from it until it is bootstraped.
This will move the page from the partial list to the cpu slab list. If this
happens, the loop:

	list_for_each_entry(p, &n->partial, lru)

that we use to scan for all partial pages will yield nothing, and the pages
will keep pointing to the boot cpu cache, which is of course, invalid. To do
that, we should flush the cache to make sure that the cpu slab is back to the
partial list.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Reported-by:  Steffen Michalke <StMichalke@web.de>
Tested-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-02-28 09:29:38 +02:00
Linus Torvalds 9043a2650c The sweeping change is to make add_taint() explicitly indicate whether to disable
lockdep, but it's a mechanical change.
 
 Cheers,
 Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module update from Rusty Russell:
 "The sweeping change is to make add_taint() explicitly indicate whether
  to disable lockdep, but it's a mechanical change."

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  MODSIGN: Add option to not sign modules during modules_install
  MODSIGN: Add -s <signature> option to sign-file
  MODSIGN: Specify the hash algorithm on sign-file command line
  MODSIGN: Simplify Makefile with a Kconfig helper
  module: clean up load_module a little more.
  modpost: Ignore ARC specific non-alloc sections
  module: constify within_module_*
  taint: add explicit flag to show whether lock dep is still OK.
  module: printk message when module signature fail taints kernel.
2013-02-25 15:41:43 -08:00
Mel Gorman 22b751c3d0 mm: rename page struct field helpers
The function names page_xchg_last_nid(), page_last_nid() and
reset_page_last_nid() were judged to be inconsistent so rename them to a
struct_field_op style pattern.  As it looked jarring to have
reset_page_mapcount() and page_nid_reset_last() beside each other in
memmap_init_zone(), this patch also renames reset_page_mapcount() to
page_mapcount_reset().  There are others like init_page_count() but as
it is used throughout the arch code a rename would likely cause more
conflicts than it is worth.

[akpm@linux-foundation.org: fix zcache]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 17:50:18 -08:00
Christoph Lameter 2c59dd6544 slab: Common Kmalloc cache determination
Extract the optimized lookup functions from slub and put them into
slab_common.c. Then make slab use these functions as well.

Joonsoo notes that this fixes some issues with constant folding which
also reduces the code size for slub.

https://lkml.org/lkml/2012/10/20/82

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-02-01 12:32:08 +02:00
Christoph Lameter f97d5f634d slab: Common function to create the kmalloc array
The kmalloc array is created in similar ways in both SLAB
and SLUB. Create a common function and have both allocators
call that function.

V1->V2:
	Whitespace cleanup

Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-02-01 12:32:08 +02:00
Christoph Lameter 9425c58e54 slab: Common definition for the array of kmalloc caches
Have a common definition fo the kmalloc cache arrays in
SLAB and SLUB

Acked-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-02-01 12:32:07 +02:00
Christoph Lameter 95a05b428c slab: Common constants for kmalloc boundaries
Standardize the constants that describe the smallest and largest
object kept in the kmalloc arrays for SLAB and SLUB.

Differentiate between the maximum size for which a slab cache is used
(KMALLOC_MAX_CACHE_SIZE) and the maximum allocatable size
(KMALLOC_MAX_SIZE, KMALLOC_MAX_ORDER).

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-02-01 12:32:07 +02:00
Rusty Russell 373d4d0997 taint: add explicit flag to show whether lock dep is still OK.
Fix up all callers as they were before, with make one change: an
unsigned module taints the kernel, but doesn't turn off lockdep.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-01-21 17:17:57 +10:30
Glauber Costa 5413dfba88 slub: drop mutex before deleting sysfs entry
Sasha Levin recently reported a lockdep problem resulting from the new
attribute propagation introduced by kmemcg series.  In short, slab_mutex
will be called from within the sysfs attribute store function.  This will
create a dependency, that will later be held backwards when a cache is
destroyed - since destruction occurs with the slab_mutex held, and then
calls in to the sysfs directory removal function.

In this patch, I propose to adopt a strategy close to what
__kmem_cache_create does before calling sysfs_slab_add, and release the
lock before the call to sysfs_slab_remove.  This is pretty much the last
operation in the kmem_cache_shutdown() path, so we could do better by
splitting this and moving this call alone to later on.  This will fit
nicely when sysfs handling is consistent between all caches, but will look
weird now.

Lockdep info:

  ======================================================
  [ INFO: possible circular locking dependency detected ]
  3.7.0-rc4-next-20121106-sasha-00008-g353b62f #117 Tainted: G        W
  -------------------------------------------------------
  trinity-child13/6961 is trying to acquire lock:
   (s_active#43){++++.+}, at:  sysfs_addrm_finish+0x31/0x60

  but task is already holding lock:
   (slab_mutex){+.+.+.}, at:  kmem_cache_destroy+0x22/0xe0

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:
  -> #1 (slab_mutex){+.+.+.}:
          lock_acquire+0x1aa/0x240
          __mutex_lock_common+0x59/0x5a0
          mutex_lock_nested+0x3f/0x50
          slab_attr_store+0xde/0x110
          sysfs_write_file+0xfa/0x150
          vfs_write+0xb0/0x180
          sys_pwrite64+0x60/0xb0
          tracesys+0xe1/0xe6
  -> #0 (s_active#43){++++.+}:
          __lock_acquire+0x14df/0x1ca0
          lock_acquire+0x1aa/0x240
          sysfs_deactivate+0x122/0x1a0
          sysfs_addrm_finish+0x31/0x60
          sysfs_remove_dir+0x89/0xd0
          kobject_del+0x16/0x40
          __kmem_cache_shutdown+0x40/0x60
          kmem_cache_destroy+0x40/0xe0
          mon_text_release+0x78/0xe0
          __fput+0x122/0x2d0
          ____fput+0x9/0x10
          task_work_run+0xbe/0x100
          do_exit+0x432/0xbd0
          do_group_exit+0x84/0xd0
          get_signal_to_deliver+0x81d/0x930
          do_signal+0x3a/0x950
          do_notify_resume+0x3e/0x90
          int_signal+0x12/0x17

  other info that might help us debug this:

   Possible unsafe locking scenario:

         CPU0                    CPU1
         ----                    ----
    lock(slab_mutex);
                                 lock(s_active#43);
                                 lock(slab_mutex);
    lock(s_active#43);

   *** DEADLOCK ***

  2 locks held by trinity-child13/6961:
   #0:  (mon_lock){+.+.+.}, at:  mon_text_release+0x25/0xe0
   #1:  (slab_mutex){+.+.+.}, at:  kmem_cache_destroy+0x22/0xe0

  stack backtrace:
  Pid: 6961, comm: trinity-child13 Tainted: G        W    3.7.0-rc4-next-20121106-sasha-00008-g353b62f #117
  Call Trace:
    print_circular_bug+0x1fb/0x20c
    __lock_acquire+0x14df/0x1ca0
    lock_acquire+0x1aa/0x240
    sysfs_deactivate+0x122/0x1a0
    sysfs_addrm_finish+0x31/0x60
    sysfs_remove_dir+0x89/0xd0
    kobject_del+0x16/0x40
    __kmem_cache_shutdown+0x40/0x60
    kmem_cache_destroy+0x40/0xe0
    mon_text_release+0x78/0xe0
    __fput+0x122/0x2d0
    ____fput+0x9/0x10
    task_work_run+0xbe/0x100
    do_exit+0x432/0xbd0
    do_group_exit+0x84/0xd0
    get_signal_to_deliver+0x81d/0x930
    do_signal+0x3a/0x950
    do_notify_resume+0x3e/0x90
    int_signal+0x12/0x17

Signed-off-by: Glauber Costa <glommer@parallels.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18 15:02:15 -08:00
Glauber Costa ebe945c276 memcg: add comments clarifying aspects of cache attribute propagation
This patch clarifies two aspects of cache attribute propagation.

First, the expected context for the for_each_memcg_cache macro in
memcontrol.h.  The usages already in the codebase are safe.  In mm/slub.c,
it is trivially safe because the lock is acquired right before the loop.
In mm/slab.c, it is less so: the lock is acquired by an outer function a
few steps back in the stack, so a VM_BUG_ON() is added to make sure it is
indeed safe.

A comment is also added to detail why we are returning the value of the
parent cache and ignoring the children's when we propagate the attributes.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18 15:02:15 -08:00
Glauber Costa 107dab5c92 slub: slub-specific propagation changes
SLUB allows us to tune a particular cache behavior with sysfs-based
tunables.  When creating a new memcg cache copy, we'd like to preserve any
tunables the parent cache already had.

This can be done by tapping into the store attribute function provided by
the allocator.  We of course don't need to mess with read-only fields.
Since the attributes can have multiple types and are stored internally by
sysfs, the best strategy is to issue a ->show() in the root cache, and
then ->store() in the memcg cache.

The drawback of that, is that sysfs can allocate up to a page in buffering
for show(), that we are likely not to need, but also can't guarantee.  To
avoid always allocating a page for that, we can update the caches at store
time with the maximum attribute size ever stored to the root cache.  We
will then get a buffer big enough to hold it.  The corolary to this, is
that if no stores happened, nothing will be propagated.

It can also happen that a root cache has its tunables updated during
normal system operation.  In this case, we will propagate the change to
all caches that are already active.

[akpm@linux-foundation.org: tweak code to avoid __maybe_unused]
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18 15:02:14 -08:00
Glauber Costa 1f458cbf12 memcg: destroy memcg caches
Implement destruction of memcg caches.  Right now, only caches where our
reference counter is the last remaining are deleted.  If there are any
other reference counters around, we just leave the caches lying around
until they go away.

When that happens, a destruction function is called from the cache code.
Caches are only destroyed in process context, so we queue them up for
later processing in the general case.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18 15:02:14 -08:00
Glauber Costa d79923fad9 sl[au]b: allocate objects from memcg cache
We are able to match a cache allocation to a particular memcg.  If the
task doesn't change groups during the allocation itself - a rare event,
this will give us a good picture about who is the first group to touch a
cache page.

This patch uses the now available infrastructure by calling
memcg_kmem_get_cache() before all the cache allocations.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18 15:02:14 -08:00
Glauber Costa b9ce5ef49f sl[au]b: always get the cache from its page in kmem_cache_free()
struct page already has this information.  If we start chaining caches,
this information will always be more trustworthy than whatever is passed
into the function.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18 15:02:14 -08:00
Glauber Costa 2633d7a028 slab/slub: consider a memcg parameter in kmem_create_cache
Allow a memcg parameter to be passed during cache creation.  When the slub
allocator is being used, it will only merge caches that belong to the same
memcg.  We'll do this by scanning the global list, and then translating
the cache to a memcg-specific cache

Default function is created as a wrapper, passing NULL to the memcg
version.  We only merge caches that belong to the same memcg.

A helper is provided, memcg_css_id: because slub needs a unique cache name
for sysfs.  Since this is visible, but not the canonical location for slab
data, the cache name is not used, the css_id should suffice.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18 15:02:13 -08:00
Linus Torvalds ae664dba27 Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
Pull SLAB changes from Pekka Enberg:
 "This contains preparational work from Christoph Lameter and Glauber
  Costa for SLAB memcg and cleanups and improvements from Ezequiel
  Garcia and Joonsoo Kim.

  Please note that the SLOB cleanup commit from Arnd Bergmann already
  appears in your tree but I had also merged it myself which is why it
  shows up in the shortlog."

* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
  mm/sl[aou]b: Common alignment code
  slab: Use the new create_boot_cache function to simplify bootstrap
  slub: Use statically allocated kmem_cache boot structure for bootstrap
  mm, sl[au]b: create common functions for boot slab creation
  slab: Simplify bootstrap
  slub: Use correct cpu_slab on dead cpu
  mm: fix slab.c kernel-doc warnings
  mm/slob: use min_t() to compare ARCH_SLAB_MINALIGN
  slab: Ignore internal flags in cache creation
  mm/slob: Use free_page instead of put_page for page-size kmalloc allocations
  mm/sl[aou]b: Move common kmem_cache_size() to slab.h
  mm/slob: Use object_size field in kmem_cache_size()
  mm/slob: Drop usage of page->private for storing page-sized allocations
  slub: Commonize slab_cache field in struct page
  sl[au]b: Process slabinfo_show in common code
  mm/sl[au]b: Move print_slabinfo_header to slab_common.c
  mm/sl[au]b: Move slabinfo processing to slab_common.c
  slub: remove one code path and reduce lock contention in __slab_free()
2012-12-18 10:56:07 -08:00
Lai Jiangshan b9d5ab2562 slub, hotplug: ignore unrelated node's hot-adding and hot-removing
SLUB only focuses on the nodes which have normal memory and it ignores the
other node's hot-adding and hot-removing.

Aka: if some memory of a node which has no onlined memory is online, but
this new memory onlined is not normal memory (for example, highmem), we
should not allocate kmem_cache_node for SLUB.

And if the last normal memory is offlined, but the node still has memory,
we should remove kmem_cache_node for that node.  (The current code delays
it when all of the memory is offlined)

So we only do something when marg->status_change_nid_normal > 0.
marg->status_change_nid is not suitable here.

The same problem doesn't exist in SLAB, because SLAB allocates kmem_list3
for every node even the node don't have normal memory, SLAB tolerates
kmem_list3 on alien nodes.  SLUB only focuses on the nodes which have
normal memory, it don't tolerate alien kmem_cache_node.  The patch makes
SLUB become self-compatible and avoids WARNs and BUGs in rare conditions.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Rob Landley <rob@landley.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-11 17:22:23 -08:00
Christoph Lameter 4590685546 mm/sl[aou]b: Common alignment code
Extract the code to do object alignment from the allocators.
Do the alignment calculations in slab_common so that the
__kmem_cache_create functions of the allocators do not have
to deal with alignment.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-12-11 12:14:28 +02:00
Christoph Lameter dffb4d605c slub: Use statically allocated kmem_cache boot structure for bootstrap
Simplify bootstrap by statically allocated two kmem_cache structures. These are
freed after bootup is complete. Allows us to no longer worry about calculations
of sizes of kmem_cache structures during bootstrap.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-12-11 12:14:27 +02:00
Christoph Lameter 45530c4474 mm, sl[au]b: create common functions for boot slab creation
Use a special function to create kmalloc caches and use that function in
SLAB and SLUB.

Acked-by: Joonsoo Kim <js1304@gmail.com>
Reviewed-by: Glauber Costa <glommer@parallels.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-12-11 12:14:27 +02:00
Christoph Lameter 59a09917c9 slub: Use correct cpu_slab on dead cpu
Pass a kmem_cache_cpu pointer into unfreeze partials so that a different
kmem_cache_cpu structure than the local one can be specified.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-12-11 12:14:27 +02:00
Glauber Costa d8843922fb slab: Ignore internal flags in cache creation
Some flags are used internally by the allocators for management
purposes. One example of that is the CFLGS_OFF_SLAB flag that slab uses
to mark that the metadata for that cache is stored outside of the slab.

No cache should ever pass those as a creation flags. We can just ignore
this bit if it happens to be passed (such as when duplicating a cache in
the kmem memcg patches).

Because such flags can vary from allocator to allocator, we allow them
to make their own decisions on that, defining SLAB_AVAILABLE_FLAGS with
all flags that are valid at creation time.  Allocators that doesn't have
any specific flag requirement should define that to mean all flags.

Common code will mask out all flags not belonging to that set.

Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-31 09:13:01 +02:00
Ezequiel Garcia 242860a47a mm/sl[aou]b: Move common kmem_cache_size() to slab.h
This function is identically defined in all three allocators
and it's trivial to move it to slab.h

Since now it's static, inline, header-defined function
this patch also drops the EXPORT_SYMBOL tag.

Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-31 08:52:15 +02:00
Glauber Costa 1b4f59e356 slub: Commonize slab_cache field in struct page
Right now, slab and slub have fields in struct page to derive which
cache a page belongs to, but they do it slightly differently.

slab uses a field called slab_cache, that lives in the third double
word. slub, uses a field called "slab", living outside of the
doublewords area.

Ideally, we could use the same field for this. Since slub heavily makes
use of the doubleword region, there isn't really much room to move
slub's slab_cache field around. Since slab does not have such strict
placement restrictions, we can move it outside the doubleword area.

The naming used by slab, "slab_cache", is less confusing, and it is
preferred over slub's generic "slab".

Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Christoph Lameter <cl@linux.com>
CC: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-24 11:58:03 +03:00
Pekka Enberg b4f591c45f Merge branch 'slab/procfs' into slab/next 2012-10-24 09:43:00 +03:00
Glauber Costa 0d7561c61d sl[au]b: Process slabinfo_show in common code
With all the infrastructure in place, we can now have slabinfo_show
done from slab_common.c. A cache-specific function is called to grab
information about the cache itself, since that is still heavily
dependent on the implementation. But with the values produced by it, all
the printing and handling is done from common code.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-24 09:39:16 +03:00
Glauber Costa bcee6e2a13 mm/sl[au]b: Move print_slabinfo_header to slab_common.c
The header format is highly similar between slab and slub. The main
difference lays in the fact that slab may optionally have statistics
added here in case of CONFIG_SLAB_DEBUG, while the slub will stick them
somewhere else.

By making sure that information conditionally lives inside a
globally-visible CONFIG_DEBUG_SLAB switch, we can move the header
printing to a common location.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Christoph Lameter <cl@linux.com>
CC: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-24 09:38:38 +03:00
Glauber Costa b7454ad3cf mm/sl[au]b: Move slabinfo processing to slab_common.c
This patch moves all the common machinery to slabinfo processing
to slab_common.c. We can do better by noticing that the output is
heavily common, and having the allocators to just provide finished
information about this. But after this first step, this can be done
easier.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Christoph Lameter <cl@linux.com>
CC: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-24 09:37:41 +03:00
Joonsoo Kim 837d678dc2 slub: remove one code path and reduce lock contention in __slab_free()
When we try to free object, there is some of case that we need
to take a node lock. This is the necessary step for preventing a race.
After taking a lock, then we try to cmpxchg_double_slab().
But, there is a possible scenario that cmpxchg_double_slab() is failed
with taking a lock. Following example explains it.

CPU A               CPU B
need lock
...                 need lock
...                 lock!!
lock..but spin      free success
spin...             unlock
lock!!
free fail

In this case, retry with taking a lock is occured in CPU A.
I think that in this case for CPU A,
"release a lock first, and re-take a lock if necessary" is preferable way.

There are two reasons for this.

First, this makes __slab_free()'s logic somehow simple.
With this patch, 'was_frozen = 1' is "always" handled without taking a lock.
So we can remove one code path.

Second, it may reduce lock contention.
When we do retrying, status of slab is already changed,
so we don't need a lock anymore in almost every case.
"release a lock first, and re-take a lock if necessary" policy is
helpful to this.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-19 10:19:24 +03:00
Pekka Enberg f4178cdddd Merge branch 'slab/common-for-cgroups' into slab/for-linus
Fix up a trivial conflict with NUMA_NO_NODE cleanups.

Conflicts:
	mm/slob.c

Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-03 09:56:37 +03:00
Pekka Enberg 023dc70470 Merge branch 'slab/next' into slab/for-linus 2012-10-03 09:56:12 +03:00
Fengguang Wu 788e1aadad slub: init_kmem_cache_cpus() and put_cpu_partial() can be static
Acked-by: Glauber Costa <glommer@parallels.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-03 09:48:41 +03:00
Ezequiel Garcia 2b847c3cb4 mm, slub: Rename slab_alloc() -> slab_alloc_node() to match SLAB
This patch does not fix anything, and its only goal is to enable us
to obtain some common code between SLAB and SLUB.
Neither behavior nor produced code is affected.

Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-25 10:18:37 +03:00
Dave Jones 645df230ca mm, sl[au]b: Taint kernel when we detect a corrupted slab
It doesn't seem worth adding a new taint flag for this, so just re-use
the one from 'bad page'

Acked-by: Christoph Lameter <cl@linux.com> # SLUB
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-19 10:08:01 +03:00
Joonsoo Kim 8ba00bb68a slub: consider pfmemalloc_match() in get_partial_node()
get_partial() is currently not checking pfmemalloc_match() meaning that
it is possible for pfmemalloc pages to leak to non-pfmemalloc users.
This is a problem in the following situation.  Assume that there is a
request from normal allocation and there are no objects in the per-cpu
cache and no node-partial slab.

In this case, slab_alloc enters the slow path and new_slab_objects() is
called which may return a PFMEMALLOC page.  As the current user is not
allowed to access PFMEMALLOC page, deactivate_slab() is called
([5091b74a: mm: slub: optimise the SLUB fast path to avoid pfmemalloc
checks]) and returns an object from PFMEMALLOC page.

Next time, when we get another request from normal allocation,
slab_alloc() enters the slow-path and calls new_slab_objects().  In
new_slab_objects(), we call get_partial() and get a partial slab which
was just deactivated but is a pfmemalloc page.  We extract one object
from it and re-deactivate.

  "deactivate -> re-get in get_partial -> re-deactivate" occures repeatedly.

As a result, access to PFMEMALLOC page is not properly restricted and it
can cause a performance degradation due to frequent deactivation.
deactivation frequently.

This patch changes get_partial_node() to take pfmemalloc_match() into
account and prevents the "deactivate -> re-get in get_partial()
scenario.  Instead, new_slab() is called.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-09-17 15:00:38 -07:00
Christoph Lameter 9df53b154a slub: Zero initial memory segment for kmem_cache and kmem_cache_node
Tony Luck reported the following problem on IA-64:

  Worked fine yesterday on next-20120905, crashes today. First sign of
  trouble was an unaligned access, then a NULL dereference. SL*B related
  bits of my config:

  CONFIG_SLUB_DEBUG=y
  # CONFIG_SLAB is not set
  CONFIG_SLUB=y
  CONFIG_SLABINFO=y
  # CONFIG_SLUB_DEBUG_ON is not set
  # CONFIG_SLUB_STATS is not set

  And he console log.

  PID hash table entries: 4096 (order: 1, 32768 bytes)
  Dentry cache hash table entries: 262144 (order: 7, 2097152 bytes)
  Inode-cache hash table entries: 131072 (order: 6, 1048576 bytes)
  Memory: 2047920k/2086064k available (13992k code, 38144k reserved,
  6012k data, 880k init)
  kernel unaligned access to 0xca2ffc55fb373e95, ip=0xa0000001001be550
  swapper[0]: error during unaligned kernel access
   -1 [1]
  Modules linked in:

  Pid: 0, CPU 0, comm:              swapper
  psr : 00001010084a2018 ifs : 800000000000060f ip  :
  [<a0000001001be550>]    Not tainted (3.6.0-rc4-zx1-smp-next-20120906)
  ip is at new_slab+0x90/0x680
  unat: 0000000000000000 pfs : 000000000000060f rsc : 0000000000000003
  rnat: 9666960159966a59 bsps: a0000001001441c0 pr  : 9666960159965a59
  ldrs: 0000000000000000 ccv : 0000000000000000 fpsr: 0009804c8a70433f
  csd : 0000000000000000 ssd : 0000000000000000
  b0  : a0000001001be500 b6  : a00000010112cb20 b7  : a0000001011660a0
  f6  : 0fff7f0f0f0f0e54f0000 f7  : 0ffe8c5c1000000000000
  f8  : 1000d8000000000000000 f9  : 100068800000000000000
  f10 : 10005f0f0f0f0e54f0000 f11 : 1003e0000000000000078
  r1  : a00000010155eef0 r2  : 0000000000000000 r3  : fffffffffffc1638
  r8  : e0000040600081b8 r9  : ca2ffc55fb373e95 r10 : 0000000000000000
  r11 : e000004040001646 r12 : a000000101287e20 r13 : a000000101280000
  r14 : 0000000000004000 r15 : 0000000000000078 r16 : ca2ffc55fb373e75
  r17 : e000004040040000 r18 : fffffffffffc1646 r19 : e000004040001646
  r20 : fffffffffffc15f8 r21 : 000000000000004d r22 : a00000010132fa68
  r23 : 00000000000000ed r24 : 0000000000000000 r25 : 0000000000000000
  r26 : 0000000000000001 r27 : a0000001012b8500 r28 : a00000010135f4a0
  r29 : 0000000000000000 r30 : 0000000000000000 r31 : 0000000000000001
  Unable to handle kernel NULL pointer dereference (address
  0000000000000018)
  swapper[0]: Oops 11003706212352 [2]
  Modules linked in:

  Pid: 0, CPU 0, comm:              swapper
  psr : 0000121008022018 ifs : 800000000000cc18 ip  :
  [<a0000001004dc8f1>]    Not tainted (3.6.0-rc4-zx1-smp-next-20120906)
  ip is at __copy_user+0x891/0x960
  unat: 0000000000000000 pfs : 0000000000000813 rsc : 0000000000000003
  rnat: 0000000000000000 bsps: 0000000000000000 pr  : 9666960159961765
  ldrs: 0000000000000000 ccv : 0000000000000000 fpsr: 0009804c0270033f
  csd : 0000000000000000 ssd : 0000000000000000
  b0  : a00000010004b550 b6  : a00000010004b740 b7  : a00000010000c750
  f6  : 000000000000000000000 f7  : 1003e9e3779b97f4a7c16
  f8  : 1003e0a00000010001550 f9  : 100068800000000000000
  f10 : 10005f0f0f0f0e54f0000 f11 : 1003e0000000000000078
  r1  : a00000010155eef0 r2  : a0000001012870b0 r3  : a0000001012870b8
  r8  : 0000000000000298 r9  : 0000000000000013 r10 : 0000000000000000
  r11 : 9666960159961a65 r12 : a000000101287010 r13 : a000000101280000
  r14 : a000000101287068 r15 : a000000101287080 r16 : 0000000000000298
  r17 : 0000000000000010 r18 : 0000000000000018 r19 : a000000101287310
  r20 : 0000000000000290 r21 : 0000000000000000 r22 : 0000000000000000
  r23 : a000000101386f58 r24 : 0000000000000000 r25 : 000000007fffffff
  r26 : a000000101287078 r27 : a0000001013c69b0 r28 : 0000000000000000
  r29 : 0000000000000014 r30 : 0000000000000000 r31 : 0000000000000813

Sedat Dilek and Hugh Dickins reported similar problems as well.

Earlier patches in the common set moved the zeroing of the kmem_cache
structure into common code. See "Move allocation of kmem_cache into
common code".

The allocation for the two special structures is still done from SLUB
specific code but no zeroing is done since the cache creation functions
used to zero. This now needs to be updated so that the structures are
zeroed during allocation in kmem_cache_init().  Otherwise random pointer
values may be followed.

Reported-by: Tony Luck <tony.luck@intel.com>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reported-by: Hugh Dickins <hughd@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-10 09:57:19 +03:00
Pekka Enberg aac3a1664a Revert "mm/sl[aou]b: Move sysfs_slab_add to common"
This reverts commit 96d17b7be0 which
caused the following errors at boot:

  [    1.114885] kobject (ffff88001a802578): tried to init an initialized object, something is seriously wrong.
  [    1.114885] Pid: 1, comm: swapper/0 Tainted: G        W    3.6.0-rc1+ #6
  [    1.114885] Call Trace:
  [    1.114885]  [<ffffffff81273f37>] kobject_init+0x87/0xa0
  [    1.115555]  [<ffffffff8127426a>] kobject_init_and_add+0x2a/0x90
  [    1.115555]  [<ffffffff8127c870>] ? sprintf+0x40/0x50
  [    1.115555]  [<ffffffff81124c60>] sysfs_slab_add+0x80/0x210
  [    1.115555]  [<ffffffff81100175>] kmem_cache_create+0xa5/0x250
  [    1.115555]  [<ffffffff81cf24cd>] ? md_init+0x144/0x144
  [    1.115555]  [<ffffffff81cf25b6>] local_init+0xa4/0x11b
  [    1.115555]  [<ffffffff81cf24e1>] dm_init+0x14/0x45
  [    1.115836]  [<ffffffff810001ba>] do_one_initcall+0x3a/0x160
  [    1.116834]  [<ffffffff81cc2c90>] kernel_init+0x133/0x1b7
  [    1.117835]  [<ffffffff81cc25c4>] ? do_early_param+0x86/0x86
  [    1.117835]  [<ffffffff8171aff4>] kernel_thread_helper+0x4/0x10
  [    1.118401]  [<ffffffff81cc2b5d>] ? start_kernel+0x33f/0x33f
  [    1.119832]  [<ffffffff8171aff0>] ? gs_change+0xb/0xb
  [    1.120325] ------------[ cut here ]------------
  [    1.120835] WARNING: at fs/sysfs/dir.c:536 sysfs_add_one+0xc1/0xf0()
  [    1.121437] sysfs: cannot create duplicate filename '/kernel/slab/:t-0000016'
  [    1.121831] Modules linked in:
  [    1.122138] Pid: 1, comm: swapper/0 Tainted: G        W    3.6.0-rc1+ #6
  [    1.122831] Call Trace:
  [    1.123074]  [<ffffffff81195ce1>] ? sysfs_add_one+0xc1/0xf0
  [    1.123833]  [<ffffffff8103adfa>] warn_slowpath_common+0x7a/0xb0
  [    1.124405]  [<ffffffff8103aed1>] warn_slowpath_fmt+0x41/0x50
  [    1.124832]  [<ffffffff81195ce1>] sysfs_add_one+0xc1/0xf0
  [    1.125337]  [<ffffffff81195eb3>] create_dir+0x73/0xd0
  [    1.125832]  [<ffffffff81196221>] sysfs_create_dir+0x81/0xe0
  [    1.126363]  [<ffffffff81273d3d>] kobject_add_internal+0x9d/0x210
  [    1.126832]  [<ffffffff812742a3>] kobject_init_and_add+0x63/0x90
  [    1.127406]  [<ffffffff81124c60>] sysfs_slab_add+0x80/0x210
  [    1.127832]  [<ffffffff81100175>] kmem_cache_create+0xa5/0x250
  [    1.128384]  [<ffffffff81cf24cd>] ? md_init+0x144/0x144
  [    1.128833]  [<ffffffff81cf25b6>] local_init+0xa4/0x11b
  [    1.129831]  [<ffffffff81cf24e1>] dm_init+0x14/0x45
  [    1.130305]  [<ffffffff810001ba>] do_one_initcall+0x3a/0x160
  [    1.130831]  [<ffffffff81cc2c90>] kernel_init+0x133/0x1b7
  [    1.131351]  [<ffffffff81cc25c4>] ? do_early_param+0x86/0x86
  [    1.131830]  [<ffffffff8171aff4>] kernel_thread_helper+0x4/0x10
  [    1.132392]  [<ffffffff81cc2b5d>] ? start_kernel+0x33f/0x33f
  [    1.132830]  [<ffffffff8171aff0>] ? gs_change+0xb/0xb
  [    1.133315] ---[ end trace 2703540871c8fab7 ]---
  [    1.133830] ------------[ cut here ]------------
  [    1.134274] WARNING: at lib/kobject.c:196 kobject_add_internal+0x1f5/0x210()
  [    1.134829] kobject_add_internal failed for :t-0000016 with -EEXIST, don't try to register things with the same name in the same directory.
  [    1.135829] Modules linked in:
  [    1.136135] Pid: 1, comm: swapper/0 Tainted: G        W    3.6.0-rc1+ #6
  [    1.136828] Call Trace:
  [    1.137071]  [<ffffffff81273e95>] ? kobject_add_internal+0x1f5/0x210
  [    1.137830]  [<ffffffff8103adfa>] warn_slowpath_common+0x7a/0xb0
  [    1.138402]  [<ffffffff8103aed1>] warn_slowpath_fmt+0x41/0x50
  [    1.138830]  [<ffffffff811955a3>] ? release_sysfs_dirent+0x73/0xf0
  [    1.139419]  [<ffffffff81273e95>] kobject_add_internal+0x1f5/0x210
  [    1.139830]  [<ffffffff812742a3>] kobject_init_and_add+0x63/0x90
  [    1.140429]  [<ffffffff81124c60>] sysfs_slab_add+0x80/0x210
  [    1.140830]  [<ffffffff81100175>] kmem_cache_create+0xa5/0x250
  [    1.141829]  [<ffffffff81cf24cd>] ? md_init+0x144/0x144
  [    1.142307]  [<ffffffff81cf25b6>] local_init+0xa4/0x11b
  [    1.142829]  [<ffffffff81cf24e1>] dm_init+0x14/0x45
  [    1.143307]  [<ffffffff810001ba>] do_one_initcall+0x3a/0x160
  [    1.143829]  [<ffffffff81cc2c90>] kernel_init+0x133/0x1b7
  [    1.144352]  [<ffffffff81cc25c4>] ? do_early_param+0x86/0x86
  [    1.144829]  [<ffffffff8171aff4>] kernel_thread_helper+0x4/0x10
  [    1.145405]  [<ffffffff81cc2b5d>] ? start_kernel+0x33f/0x33f
  [    1.145828]  [<ffffffff8171aff0>] ? gs_change+0xb/0xb
  [    1.146313] ---[ end trace 2703540871c8fab8 ]---

Conflicts:

	mm/slub.c

Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:07:44 +03:00
Christoph Lameter cce89f4f69 mm/sl[aou]b: Move kmem_cache refcounting to common code
Get rid of the refcount stuff in the allocators and do that part of
kmem_cache management in the common code.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:00:37 +03:00
Christoph Lameter 8a13a4cc80 mm/sl[aou]b: Shrink __kmem_cache_create() parameter lists
Do the initial settings of the fields in common code. This will allow us
to push more processing into common code later and improve readability.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:00:37 +03:00
Christoph Lameter 278b1bb131 mm/sl[aou]b: Move kmem_cache allocations into common code
Shift the allocations to common code. That way the allocation and
freeing of the kmem_cache structures is handled by common code.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:00:36 +03:00
Christoph Lameter 96d17b7be0 mm/sl[aou]b: Move sysfs_slab_add to common
Simplify locking by moving the slab_add_sysfs after all locks have been
dropped. Eases the upcoming move to provide sysfs support for all
allocators.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:00:36 +03:00
Christoph Lameter cbb79694d5 mm/sl[aou]b: Do slab aliasing call from common code
The slab aliasing logic causes some strange contortions in slub. So add
a call to deal with aliases to slab_common.c but disable it for other
slab allocators by providng stubs that fail to create aliases.

Full general support for aliases will require additional cleanup passes
and more standardization of fields in kmem_cache.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:00:36 +03:00
Christoph Lameter db265eca77 mm/sl[aou]b: Move duping of slab name to slab_common.c
Duping of the slabname has to be done by each slab. Moving this code to
slab_common avoids duplicate implementations.

With this patch we have common string handling for all slab allocators.
Strings passed to kmem_cache_create() are copied internally. Subsystems
can create temporary strings to create slab caches.

Slabs allocated in early states of bootstrap will never be freed (and
those can never be freed since they are essential to slab allocator
operations).  During bootstrap we therefore do not have to worry about
duping names.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:00:36 +03:00
Christoph Lameter 12c3667fb7 mm/sl[aou]b: Get rid of __kmem_cache_destroy
What is done there can be done in __kmem_cache_shutdown.

This affects RCU handling somewhat. On rcu free all slab allocators do
not refer to other management structures than the kmem_cache structure.
Therefore these other structures can be freed before the rcu deferred
free to the page allocator occurs.

Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:00:36 +03:00
Christoph Lameter 8f4c765c22 mm/sl[aou]b: Move freeing of kmem_cache structure to common code
The freeing action is basically the same in all slab allocators.
Move to the common kmem_cache_destroy() function.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:00:36 +03:00
Christoph Lameter 9b030cb865 mm/sl[aou]b: Use "kmem_cache" name for slab cache with kmem_cache struct
Make all allocators use the "kmem_cache" slabname for the "kmem_cache"
structure.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:00:36 +03:00
Christoph Lameter 945cf2b619 mm/sl[aou]b: Extract a common function for kmem_cache_destroy
kmem_cache_destroy does basically the same in all allocators.

Extract common code which is easy since we already have common mutex
handling.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:00:35 +03:00
Christoph Lameter 7c9adf5a54 mm/sl[aou]b: Move list_add() to slab_common.c
Move the code to append the new kmem_cache to the list of slab caches to
the kmem_cache_create code in the shared code.

This is possible now since the acquisition of the mutex was moved into
kmem_cache_create().

Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:00:35 +03:00
Christoph Lameter 208c4358dc mm/slub: Use kmem_cache for the kmem_cache structure
Do not use kmalloc() but kmem_cache_alloc() for the allocation
of the kmem_cache structures in slub.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:00:35 +03:00
Christoph Lameter 79576102af mm/slub: Add debugging to verify correct cache use on kmem_cache_free()
Add additional debugging to check that the objects is actually from the cache
the caller claims. Doing so currently trips up some other debugging code. It
takes a lot to infer from that what was happening.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
[ penberg@kernel.org: Use pr_err() ]
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05 12:00:35 +03:00
Joonsoo Kim e24fc410f5 slub: reduce failure of this_cpu_cmpxchg in put_cpu_partial() after unfreezing
In current implementation, after unfreezing, we doesn't touch oldpage,
so it remain 'NOT NULL'. When we call this_cpu_cmpxchg()
with this old oldpage, this_cpu_cmpxchg() is mostly be failed.

We can change value of oldpage to NULL after unfreezing,
because unfreeze_partial() ensure that all the cpu partial slabs is removed
from cpu partial list. In this time, we could expect that
this_cpu_cmpxchg is mostly succeed.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-08-16 10:06:42 +03:00
Christoph Lameter 19c7ff9ecd slub: Take node lock during object free checks
Only applies to scenarios where debugging is on:

Validation of slabs can currently occur while debugging
information is updated from the fast paths of the allocator.
This results in various races where we get false reports about
slab metadata not being in order.

This patch makes the fast paths take the node lock so that
serialization with slab validation will occur. Causes additional
slowdown in debug scenarios.

Reported-by: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-08-16 09:45:04 +03:00
Glauber Costa d9b7f22623 slub: use free_page instead of put_page for freeing kmalloc allocation
When freeing objects, the slub allocator will most of the time free
empty pages by calling __free_pages(). But high-order kmalloc will be
diposed by means of put_page() instead. It makes no sense to call
put_page() in kernel pages that are provided by the object allocators,
so we shouldn't be doing this ourselves. Aside from the consistency
change, we don't change the flow too much. put_page()'s would call its
dtor function, which is __free_pages. We also already do all of the
Compound page tests ourselves, and the Mlock test we lose don't really
matter.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Christoph Lameter <cl@linux.com>
CC: David Rientjes <rientjes@google.com>
CC: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-08-16 09:25:03 +03:00
Christoph Lameter 5091b74a95 mm: slub: optimise the SLUB fast path to avoid pfmemalloc checks
This patch removes the check for pfmemalloc from the alloc hotpath and
puts the logic after the election of a new per cpu slab.  For a pfmemalloc
page we do not use the fast path but force the use of the slow path which
is also used for the debug case.

This has the side-effect of weakening pfmemalloc processing in the
following way;

1. A process that is allocating for network swap calls __slab_alloc.
   pfmemalloc_match is true so the freelist is loaded and c->freelist is
   now pointing to a pfmemalloc page.

2. A process that is attempting normal allocations calls slab_alloc,
   finds the pfmemalloc page on the freelist and uses it because it did
   not check pfmemalloc_match()

The patch allows non-pfmemalloc allocations to use pfmemalloc pages with
the kmalloc slabs being the most vunerable caches on the grounds they
are most likely to have a mix of pfmemalloc and !pfmemalloc requests. A
later patch will still protect the system as processes will get throttled
if the pfmemalloc reserves get depleted but performance will not degrade
as smoothly.

[mgorman@suse.de: Expanded changelog]
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-31 18:42:45 -07:00
Mel Gorman 072bb0aa5e mm: sl[au]b: add knowledge of PFMEMALLOC reserve pages
When a user or administrator requires swap for their application, they
create a swap partition and file, format it with mkswap and activate it
with swapon.  Swap over the network is considered as an option in diskless
systems.  The two likely scenarios are when blade servers are used as part
of a cluster where the form factor or maintenance costs do not allow the
use of disks and thin clients.

The Linux Terminal Server Project recommends the use of the Network Block
Device (NBD) for swap according to the manual at
https://sourceforge.net/projects/ltsp/files/Docs-Admin-Guide/LTSPManual.pdf/download
There is also documentation and tutorials on how to setup swap over NBD at
places like https://help.ubuntu.com/community/UbuntuLTSP/EnableNBDSWAP The
nbd-client also documents the use of NBD as swap.  Despite this, the fact
is that a machine using NBD for swap can deadlock within minutes if swap
is used intensively.  This patch series addresses the problem.

The core issue is that network block devices do not use mempools like
normal block devices do.  As the host cannot control where they receive
packets from, they cannot reliably work out in advance how much memory
they might need.  Some years ago, Peter Zijlstra developed a series of
patches that supported swap over an NFS that at least one distribution is
carrying within their kernels.  This patch series borrows very heavily
from Peter's work to support swapping over NBD as a pre-requisite to
supporting swap-over-NFS.  The bulk of the complexity is concerned with
preserving memory that is allocated from the PFMEMALLOC reserves for use
by the network layer which is needed for both NBD and NFS.

Patch 1 adds knowledge of the PFMEMALLOC reserves to SLAB and SLUB to
	preserve access to pages allocated under low memory situations
	to callers that are freeing memory.

Patch 2 optimises the SLUB fast path to avoid pfmemalloc checks

Patch 3 introduces __GFP_MEMALLOC to allow access to the PFMEMALLOC
	reserves without setting PFMEMALLOC.

Patch 4 opens the possibility for softirqs to use PFMEMALLOC reserves
	for later use by network packet processing.

Patch 5 only sets page->pfmemalloc when ALLOC_NO_WATERMARKS was required

Patch 6 ignores memory policies when ALLOC_NO_WATERMARKS is set.

Patches 7-12 allows network processing to use PFMEMALLOC reserves when
	the socket has been marked as being used by the VM to clean pages. If
	packets are received and stored in pages that were allocated under
	low-memory situations and are unrelated to the VM, the packets
	are dropped.

	Patch 11 reintroduces __skb_alloc_page which the networking
	folk may object to but is needed in some cases to propogate
	pfmemalloc from a newly allocated page to an skb. If there is a
	strong objection, this patch can be dropped with the impact being
	that swap-over-network will be slower in some cases but it should
	not fail.

Patch 13 is a micro-optimisation to avoid a function call in the
	common case.

Patch 14 tags NBD sockets as being SOCK_MEMALLOC so they can use
	PFMEMALLOC if necessary.

Patch 15 notes that it is still possible for the PFMEMALLOC reserve
	to be depleted. To prevent this, direct reclaimers get throttled on
	a waitqueue if 50% of the PFMEMALLOC reserves are depleted.  It is
	expected that kswapd and the direct reclaimers already running
	will clean enough pages for the low watermark to be reached and
	the throttled processes are woken up.

Patch 16 adds a statistic to track how often processes get throttled

Some basic performance testing was run using kernel builds, netperf on
loopback for UDP and TCP, hackbench (pipes and sockets), iozone and
sysbench.  Each of them were expected to use the sl*b allocators
reasonably heavily but there did not appear to be significant performance
variances.

For testing swap-over-NBD, a machine was booted with 2G of RAM with a
swapfile backed by NBD.  8*NUM_CPU processes were started that create
anonymous memory mappings and read them linearly in a loop.  The total
size of the mappings were 4*PHYSICAL_MEMORY to use swap heavily under
memory pressure.

Without the patches and using SLUB, the machine locks up within minutes
and runs to completion with them applied.  With SLAB, the story is
different as an unpatched kernel run to completion.  However, the patched
kernel completed the test 45% faster.

MICRO
                                         3.5.0-rc2 3.5.0-rc2
					 vanilla     swapnbd
Unrecognised test vmscan-anon-mmap-write
MMTests Statistics: duration
Sys Time Running Test (seconds)             197.80    173.07
User+Sys Time Running Test (seconds)        206.96    182.03
Total Elapsed Time (seconds)               3240.70   1762.09

This patch: mm: sl[au]b: add knowledge of PFMEMALLOC reserve pages

Allocations of pages below the min watermark run a risk of the machine
hanging due to a lack of memory.  To prevent this, only callers who have
PF_MEMALLOC or TIF_MEMDIE set and are not processing an interrupt are
allowed to allocate with ALLOC_NO_WATERMARKS.  Once they are allocated to
a slab though, nothing prevents other callers consuming free objects
within those slabs.  This patch limits access to slab pages that were
alloced from the PFMEMALLOC reserves.

When this patch is applied, pages allocated from below the low watermark
are returned with page->pfmemalloc set and it is up to the caller to
determine how the page should be protected.  SLAB restricts access to any
page with page->pfmemalloc set to callers which are known to able to
access the PFMEMALLOC reserve.  If one is not available, an attempt is
made to allocate a new page rather than use a reserve.  SLUB is a bit more
relaxed in that it only records if the current per-CPU page was allocated
from PFMEMALLOC reserve and uses another partial slab if the caller does
not have the necessary GFP or process flags.  This was found to be
sufficient in tests to avoid hangs due to SLUB generally maintaining
smaller lists than SLAB.

In low-memory conditions it does mean that !PFMEMALLOC allocators can fail
a slab allocation even though free objects are available because they are
being preserved for callers that are freeing pages.

[a.p.zijlstra@chello.nl: Original implementation]
[sebastian@breakpoint.cc: Correct order of page flag clearing]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-31 18:42:45 -07:00
David Rientjes 737b719ed6 mm, slub: ensure irqs are enabled for kmemcheck
kmemcheck_alloc_shadow() requires irqs to be enabled, so wait to disable
them until after its called for __GFP_WAIT allocations.

This fixes a warning for such allocations:

	WARNING: at kernel/lockdep.c:2739 lockdep_trace_alloc+0x14e/0x1c0()

Acked-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Tested-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-07-10 22:43:52 +03:00
Christoph Lameter 20cea9683e mm, sl[aou]b: Move kmem_cache_create mutex handling to common code
Move the mutex handling into the common kmem_cache_create()
function.

Then we can also move more checks out of SLAB's kmem_cache_create()
into the common code.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-07-09 12:13:42 +03:00
Christoph Lameter 18004c5d40 mm, sl[aou]b: Use a common mutex definition
Use the mutex definition from SLAB and make it the common way to take a sleeping lock.

This has the effect of using a mutex instead of a rw semaphore for SLUB.

SLOB gains the use of a mutex for kmem_cache_create serialization.
Not needed now but SLOB may acquire some more features later (like slabinfo
/ sysfs support) through the expansion of the common code that will
need this.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-07-09 12:13:41 +03:00
Christoph Lameter 97d0660915 mm, sl[aou]b: Common definition for boot state of the slab allocators
All allocators have some sort of support for the bootstrap status.

Setup a common definition for the boot states and make all slab
allocators use that definition.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-07-09 12:13:35 +03:00
Christoph Lameter 039363f38b mm, sl[aou]b: Extract common code for kmem_cache_create()
Kmem_cache_create() does a variety of sanity checks but those
vary depending on the allocator. Use the strictest tests and put them into
a slab_common file. Make the tests conditional on CONFIG_DEBUG_VM.

This patch has the effect of adding sanity checks for SLUB and SLOB
under CONFIG_DEBUG_VM and removes the checks in SLAB for !CONFIG_DEBUG_VM.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-07-09 12:13:30 +03:00
Julia Lawall 068ce415be slub: remove invalid reference to list iterator variable
If list_for_each_entry, etc complete a traversal of the list, the iterator
variable ends up pointing to an address at an offset from the list head,
and not a meaningful structure.  Thus this value should not be used after
the end of the iterator.  The patch replaces s->name by al->name, which is
referenced nearby.

This problem was found using Coccinelle (http://coccinelle.lip6.fr/).

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-07-09 12:04:34 +03:00
Joonsoo Kim 43d77867a4 slub: refactoring unfreeze_partials()
Current implementation of unfreeze_partials() is so complicated,
but benefit from it is insignificant. In addition many code in
do {} while loop have a bad influence to a fail rate of cmpxchg_double_slab.
Under current implementation which test status of cpu partial slab
and acquire list_lock in do {} while loop,
we don't need to acquire a list_lock and gain a little benefit
when front of the cpu partial slab is to be discarded, but this is a rare case.
In case that add_partial is performed and cmpxchg_double_slab is failed,
remove_partial should be called case by case.

I think that these are disadvantages of current implementation,
so I do refactoring unfreeze_partials().

Minimizing code in do {} while loop introduce a reduced fail rate
of cmpxchg_double_slab. Below is output of 'slabinfo -r kmalloc-256'
when './perf stat -r 33 hackbench 50 process 4000 > /dev/null' is done.

** before **
Cmpxchg_double Looping
------------------------
Locked Cmpxchg Double redos   182685
Unlocked Cmpxchg Double redos 0

** after **
Cmpxchg_double Looping
------------------------
Locked Cmpxchg Double redos   177995
Unlocked Cmpxchg Double redos 1

We can see cmpxchg_double_slab fail rate is improved slightly.

Bolow is output of './perf stat -r 30 hackbench 50 process 4000 > /dev/null'.

** before **
 Performance counter stats for './hackbench 50 process 4000' (30 runs):

     108517.190463 task-clock                #    7.926 CPUs utilized            ( +-  0.24% )
         2,919,550 context-switches          #    0.027 M/sec                    ( +-  3.07% )
           100,774 CPU-migrations            #    0.929 K/sec                    ( +-  4.72% )
           124,201 page-faults               #    0.001 M/sec                    ( +-  0.15% )
   401,500,234,387 cycles                    #    3.700 GHz                      ( +-  0.24% )
   <not supported> stalled-cycles-frontend
   <not supported> stalled-cycles-backend
   250,576,913,354 instructions              #    0.62  insns per cycle          ( +-  0.13% )
    45,934,956,860 branches                  #  423.297 M/sec                    ( +-  0.14% )
       188,219,787 branch-misses             #    0.41% of all branches          ( +-  0.56% )

      13.691837307 seconds time elapsed                                          ( +-  0.24% )

** after **
 Performance counter stats for './hackbench 50 process 4000' (30 runs):

     107784.479767 task-clock                #    7.928 CPUs utilized            ( +-  0.22% )
         2,834,781 context-switches          #    0.026 M/sec                    ( +-  2.33% )
            93,083 CPU-migrations            #    0.864 K/sec                    ( +-  3.45% )
           123,967 page-faults               #    0.001 M/sec                    ( +-  0.15% )
   398,781,421,836 cycles                    #    3.700 GHz                      ( +-  0.22% )
   <not supported> stalled-cycles-frontend
   <not supported> stalled-cycles-backend
   250,189,160,419 instructions              #    0.63  insns per cycle          ( +-  0.09% )
    45,855,370,128 branches                  #  425.436 M/sec                    ( +-  0.10% )
       169,881,248 branch-misses             #    0.37% of all branches          ( +-  0.43% )

      13.596272341 seconds time elapsed                                          ( +-  0.22% )

No regression is found, but rather we can see slightly better result.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-20 10:17:45 +03:00
Joonsoo Kim d24ac77f71 slub: use __cmpxchg_double_slab() at interrupt disabled place
get_freelist(), unfreeze_partials() are only called with interrupt disabled,
so __cmpxchg_double_slab() is suitable.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-20 10:13:01 +03:00
Andi Kleen e7b691b085 slab/mempolicy: always use local policy from interrupt context
slab_node() could access current->mempolicy from interrupt context.
However there's a race condition during exit where the mempolicy
is first freed and then the pointer zeroed.

Using this from interrupts seems bogus anyways. The interrupt
will interrupt a random process and therefore get a random
mempolicy. Many times, this will be idle's, which noone can change.

Just disable this here and always use local for slab
from interrupts. I also cleaned up the callers of slab_node a bit
which always passed the same argument.

I believe the original mempolicy code did that in fact,
so it's likely a regression.

v2: send version with correct logic
v3: simplify. fix typo.
Reported-by: Arun Sharma <asharma@fb.com>
Cc: penberg@kernel.org
Cc: cl@linux.com
Signed-off-by: Andi Kleen <ak@linux.intel.com>
[tdmackey@twitter.com: Rework control flow based on feedback from
cl@linux.com, fix logic, and cleanup current task_struct reference]
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: David Mackey <tdmackey@twitter.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-20 10:01:04 +03:00
Christoph Lameter 3b0efdfa1e mm, sl[aou]b: Extract common fields from struct kmem_cache
Define a struct that describes common fields used in all slab allocators.
A slab allocator either uses the common definition (like SLOB) or is
required to provide members of kmem_cache with the definition given.

After that it will be possible to share code that
only operates on those fields of kmem_cache.

The patch basically takes the slob definition of kmem cache and
uses the field namees for the other allocators.

It also standardizes the names used for basic object lengths in
allocators:

object_size	Struct size specified at kmem_cache_create. Basically
		the payload expected to be used by the subsystem.

size		The size of memory allocator for each object. This size
		is larger than object_size and includes padding, alignment
		and extra metadata for each object (f.e. for debugging
		and rcu).

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-14 09:20:16 +03:00
Pekka Enberg 23910c50cc Merge branch 'slub/cleanups' into slab/next
* Fix a merge conflict in mm/slub.c::acquire_slab() due to commit 02d7633
  ("slub: fix a memory leak in get_partial_node()").

Conflicts:
	mm/slub.c

Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-04 10:14:58 +03:00
Linus Torvalds af4f8ba31a Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
Pull slab updates from Pekka Enberg:
 "Mainly a bunch of SLUB fixes from Joonsoo Kim"

* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
  slub: use __SetPageSlab function to set PG_slab flag
  slub: fix a memory leak in get_partial_node()
  slub: remove unused argument of init_kmem_cache_node()
  slub: fix a possible memory leak
  Documentations: Fix slabinfo.c directory in vm/slub.txt
  slub: fix incorrect return type of get_any_partial()
2012-06-01 16:50:23 -07:00
Christoph Lameter 57d437d2aa slub: pass page to node_match() instead of kmem_cache_cpu structure
Avoid passing the kmem_cache_cpu pointer to node_match. This makes the
node_match function more generic and easier to understand.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-01 09:25:41 +03:00
Christoph Lameter f6e7def7f7 slub: Use page variable instead of c->page.
Store the value of c->page to avoid additional fetches
from per cpu data.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-01 09:25:41 +03:00
Christoph Lameter c17dda40a6 slub: Separate out kmem_cache_cpu processing from deactivate_slab
Processing on fields of kmem_cache_cpu is cleaner if code working on fields
of this struct is taken out of deactivate_slab().

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-01 09:25:41 +03:00
Christoph Lameter ec3ab083a7 slub: Get rid of the node field
The node field is always page_to_nid(c->page). So its rather easy to
replace. Note that there maybe slightly more overhead in various hot paths
due to the need to shift the bits from page->flags. However, that is mostly
compensated for by a smaller footprint of the kmem_cache_cpu structure (this
patch reduces that to 3 words per cache) which allows better caching.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-01 09:25:41 +03:00
Christoph Lameter 188fd06320 slub: new_slab_objects() can also get objects from partial list
Moving the attempt to get a slab page from the partial lists simplifies
__slab_alloc which is rather complicated.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-01 09:25:40 +03:00
Christoph Lameter f469743673 slub: Simplify control flow in __slab_alloc()
Simplify control flow a bit avoiding nesting.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-01 09:25:40 +03:00
Christoph Lameter 7ced371971 slub: Acquire_slab() avoid loop
Avoid the loop in acquire slab and simply fail if there is a conflict.

This will cause the next page on the list to be considered.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-01 09:25:40 +03:00
Christoph Lameter 507effeaba slub: Add frozen check in __slab_alloc
Verify that objects returned from __slab_alloc come from slab pages
in the correct state.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-01 09:25:40 +03:00
Christoph Lameter 6faa68337b slub: Use freelist instead of "object" in __slab_alloc
The variable "object" really refers to a list of objects that we
are handling.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-01 09:25:40 +03:00
Joonsoo Kim c03f94ccbd slub: use __SetPageSlab function to set PG_slab flag
To set page-flag, using SetPageXXXX() and __SetPageXXXX() is more
understandable and maintainable. So change it.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-05-18 12:28:06 +03:00
Joonsoo Kim 02d7633fa5 slub: fix a memory leak in get_partial_node()
In the case which is below,

1. acquire slab for cpu partial list
2. free object to it by remote cpu
3. page->freelist = t

then memory leak is occurred.

Change acquire_slab() not to zap freelist when it works for cpu partial list.
I think it is a sufficient solution for fixing a memory leak.

Below is output of 'slabinfo -r kmalloc-256'
when './perf stat -r 30 hackbench 50 process 4000 > /dev/null' is done.

***Vanilla***
Sizes (bytes)     Slabs              Debug                Memory
------------------------------------------------------------------------
Object :     256  Total  :     468   Sanity Checks : Off  Total: 3833856
SlabObj:     256  Full   :     111   Redzoning     : Off  Used : 2004992
SlabSiz:    8192  Partial:     302   Poisoning     : Off  Loss : 1828864
Loss   :       0  CpuSlab:      55   Tracking      : Off  Lalig:       0
Align  :       8  Objects:      32   Tracing       : Off  Lpadd:       0

***Patched***
Sizes (bytes)     Slabs              Debug                Memory
------------------------------------------------------------------------
Object :     256  Total  :     300   Sanity Checks : Off  Total: 2457600
SlabObj:     256  Full   :     204   Redzoning     : Off  Used : 2348800
SlabSiz:    8192  Partial:      33   Poisoning     : Off  Loss :  108800
Loss   :       0  CpuSlab:      63   Tracking      : Off  Lalig:       0
Align  :       8  Objects:      32   Tracing       : Off  Lpadd:       0

Total and loss number is the impact of this patch.

Cc: <stable@vger.kernel.org>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-05-18 12:23:36 +03:00
majianpeng 02e1a9cd1e slub: missing test for partial pages flush work in flush_all()
I found some kernel messages such as:

    SLUB raid5-md127: kmem_cache_destroy called for cache that still has objects.
    Pid: 6143, comm: mdadm Tainted: G           O 3.4.0-rc6+        #75
    Call Trace:
    kmem_cache_destroy+0x328/0x400
    free_conf+0x2d/0xf0 [raid456]
    stop+0x41/0x60 [raid456]
    md_stop+0x1a/0x60 [md_mod]
    do_md_stop+0x74/0x470 [md_mod]
    md_ioctl+0xff/0x11f0 [md_mod]
    blkdev_ioctl+0xd8/0x7a0
    block_ioctl+0x3b/0x40
    do_vfs_ioctl+0x96/0x560
    sys_ioctl+0x91/0xa0
    system_call_fastpath+0x16/0x1b

Then using kmemleak I found these messages:

    unreferenced object 0xffff8800b6db7380 (size 112):
      comm "mdadm", pid 5783, jiffies 4294810749 (age 90.589s)
      hex dump (first 32 bytes):
        01 01 db b6 ad 4e ad de ff ff ff ff ff ff ff ff  .....N..........
        ff ff ff ff ff ff ff ff 98 40 4a 82 ff ff ff ff  .........@J.....
      backtrace:
        kmemleak_alloc+0x21/0x50
        kmem_cache_alloc+0xeb/0x1b0
        kmem_cache_open+0x2f1/0x430
        kmem_cache_create+0x158/0x320
        setup_conf+0x649/0x770 [raid456]
        run+0x68b/0x840 [raid456]
        md_run+0x529/0x940 [md_mod]
        do_md_run+0x18/0xc0 [md_mod]
        md_ioctl+0xba8/0x11f0 [md_mod]
        blkdev_ioctl+0xd8/0x7a0
        block_ioctl+0x3b/0x40
        do_vfs_ioctl+0x96/0x560
        sys_ioctl+0x91/0xa0
        system_call_fastpath+0x16/0x1b

This bug was introduced by commit a8364d5555 ("slub: only IPI CPUs that
have per cpu obj to flush"), which did not include checks for per cpu
partial pages being present on a cpu.

Signed-off-by: majianpeng <majianpeng@gmail.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Tested-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-17 18:00:51 -07:00
Joonsoo Kim 4053497d6a slub: remove unused argument of init_kmem_cache_node()
We don't use the argument since commit 3b89d7d881
('slub: move min_partial to struct kmem_cache'), so remove it

Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-05-16 09:45:45 +03:00
Joonsoo Kim 601d39d00c slub: fix a possible memory leak
Memory allocated by kstrdup should be freed,
when kmalloc(kmem_size, GFP_KERNEL) is failed.

Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-05-16 09:37:25 +03:00
Joonsoo Kim de3ec03562 slub: fix incorrect return type of get_any_partial()
Commit 497b66f2ec ('slub: return object pointer
from get_partial() / new_slab().') changed return type of some functions.
This updates missing part.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-05-08 08:31:57 +03:00
Linus Torvalds 532bfc851a Merge branch 'akpm' (Andrew's patch-bomb)
Merge third batch of patches from Andrew Morton:
 - Some MM stragglers
 - core SMP library cleanups (on_each_cpu_mask)
 - Some IPI optimisations
 - kexec
 - kdump
 - IPMI
 - the radix-tree iterator work
 - various other misc bits.

 "That'll do for -rc1.  I still have ~10 patches for 3.4, will send
  those along when they've baked a little more."

* emailed from Andrew Morton <akpm@linux-foundation.org>: (35 commits)
  backlight: fix typo in tosa_lcd.c
  crc32: add help text for the algorithm select option
  mm: move hugepage test examples to tools/testing/selftests/vm
  mm: move slabinfo.c to tools/vm
  mm: move page-types.c from Documentation to tools/vm
  selftests/Makefile: make `run_tests' depend on `all'
  selftests: launch individual selftests from the main Makefile
  radix-tree: use iterators in find_get_pages* functions
  radix-tree: rewrite gang lookup using iterator
  radix-tree: introduce bit-optimized iterator
  fs/proc/namespaces.c: prevent crash when ns_entries[] is empty
  nbd: rename the nbd_device variable from lo to nbd
  pidns: add reboot_pid_ns() to handle the reboot syscall
  sysctl: use bitmap library functions
  ipmi: use locks on watchdog timeout set on reboot
  ipmi: simplify locking
  ipmi: fix message handling during panics
  ipmi: use a tasklet for handling received messages
  ipmi: increase KCS timeouts
  ipmi: decrease the IPMI message transaction time in interrupt mode
  ...
2012-03-28 17:19:28 -07:00
Gilad Ben-Yossef a8364d5555 slub: only IPI CPUs that have per cpu obj to flush
flush_all() is called for each kmem_cache_destroy().  So every cache being
destroyed dynamically ends up sending an IPI to each CPU in the system,
regardless if the cache has ever been used there.

For example, if you close the Infinband ipath driver char device file, the
close file ops calls kmem_cache_destroy().  So running some infiniband
config tool on one a single CPU dedicated to system tasks might interrupt
the rest of the 127 CPUs dedicated to some CPU intensive or latency
sensitive task.

I suspect there is a good chance that every line in the output of "git
grep kmem_cache_destroy linux/ | grep '\->'" has a similar scenario.

This patch attempts to rectify this issue by sending an IPI to flush the
per cpu objects back to the free lists only to CPUs that seem to have such
objects.

The check which CPU to IPI is racy but we don't care since asking a CPU
without per cpu objects to flush does no damage and as far as I can tell
the flush_all by itself is racy against allocs on remote CPUs anyway, so
if you required the flush_all to be determinstic, you had to arrange for
locking regardless.

Without this patch the following artificial test case:

$ cd /sys/kernel/slab
$ for DIR in *; do cat $DIR/alloc_calls > /dev/null; done

produces 166 IPIs on an cpuset isolated CPU. With it it produces none.

The code path of memory allocation failure for CPUMASK_OFFSTACK=y
config was tested using fault injection framework.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Sasha Levin <levinsasha928@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Avi Kivity <avi@redhat.com>
Cc: Michal Nazarewicz <mina86@mina86.org>
Cc: Kosaki Motohiro <kosaki.motohiro@gmail.com>
Cc: Milton Miller <miltonm@bga.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-28 17:14:35 -07:00
Linus Torvalds 0c9aac0826 Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
Pull SLAB changes from Pekka Enberg:
 "There's the new kmalloc_array() API, minor fixes and performance
  improvements, but quite honestly, nothing terribly exciting."

* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
  mm: SLAB Out-of-memory diagnostics
  slab: introduce kmalloc_array()
  slub: per cpu partial statistics change
  slub: include include for prefetch
  slub: Do not hold slub_lock when calling sysfs_slab_add()
  slub: prefetch next freelist pointer in slab_alloc()
  slab, cleanup: remove unneeded return
2012-03-28 15:04:26 -07:00
Mel Gorman cc9a6c8776 cpuset: mm: reduce large amounts of memory barrier related damage v3
Commit c0ff7453bb ("cpuset,mm: fix no node to alloc memory when
changing cpuset's mems") wins a super prize for the largest number of
memory barriers entered into fast paths for one commit.

[get|put]_mems_allowed is incredibly heavy with pairs of full memory
barriers inserted into a number of hot paths.  This was detected while
investigating at large page allocator slowdown introduced some time
after 2.6.32.  The largest portion of this overhead was shown by
oprofile to be at an mfence introduced by this commit into the page
allocator hot path.

For extra style points, the commit introduced the use of yield() in an
implementation of what looks like a spinning mutex.

This patch replaces the full memory barriers on both read and write
sides with a sequence counter with just read barriers on the fast path
side.  This is much cheaper on some architectures, including x86.  The
main bulk of the patch is the retry logic if the nodemask changes in a
manner that can cause a false failure.

While updating the nodemask, a check is made to see if a false failure
is a risk.  If it is, the sequence number gets bumped and parallel
allocators will briefly stall while the nodemask update takes place.

In a page fault test microbenchmark, oprofile samples from
__alloc_pages_nodemask went from 4.53% of all samples to 1.15%.  The
actual results were

                             3.3.0-rc3          3.3.0-rc3
                             rc3-vanilla        nobarrier-v2r1
    Clients   1 UserTime       0.07 (  0.00%)   0.08 (-14.19%)
    Clients   2 UserTime       0.07 (  0.00%)   0.07 (  2.72%)
    Clients   4 UserTime       0.08 (  0.00%)   0.07 (  3.29%)
    Clients   1 SysTime        0.70 (  0.00%)   0.65 (  6.65%)
    Clients   2 SysTime        0.85 (  0.00%)   0.82 (  3.65%)
    Clients   4 SysTime        1.41 (  0.00%)   1.41 (  0.32%)
    Clients   1 WallTime       0.77 (  0.00%)   0.74 (  4.19%)
    Clients   2 WallTime       0.47 (  0.00%)   0.45 (  3.73%)
    Clients   4 WallTime       0.38 (  0.00%)   0.37 (  1.58%)
    Clients   1 Flt/sec/cpu  497620.28 (  0.00%) 520294.53 (  4.56%)
    Clients   2 Flt/sec/cpu  414639.05 (  0.00%) 429882.01 (  3.68%)
    Clients   4 Flt/sec/cpu  257959.16 (  0.00%) 258761.48 (  0.31%)
    Clients   1 Flt/sec      495161.39 (  0.00%) 517292.87 (  4.47%)
    Clients   2 Flt/sec      820325.95 (  0.00%) 850289.77 (  3.65%)
    Clients   4 Flt/sec      1020068.93 (  0.00%) 1022674.06 (  0.26%)
    MMTests Statistics: duration
    Sys Time Running Test (seconds)             135.68    132.17
    User+Sys Time Running Test (seconds)         164.2    160.13
    Total Elapsed Time (seconds)                123.46    120.87

The overall improvement is small but the System CPU time is much
improved and roughly in correlation to what oprofile reported (these
performance figures are without profiling so skew is expected).  The
actual number of page faults is noticeably improved.

For benchmarks like kernel builds, the overall benefit is marginal but
the system CPU time is slightly reduced.

To test the actual bug the commit fixed I opened two terminals.  The
first ran within a cpuset and continually ran a small program that
faulted 100M of anonymous data.  In a second window, the nodemask of the
cpuset was continually randomised in a loop.

Without the commit, the program would fail every so often (usually
within 10 seconds) and obviously with the commit everything worked fine.
With this patch applied, it also worked fine so the fix should be
functionally equivalent.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-21 17:54:59 -07:00
Alex Shi 8028dcea8a slub: per cpu partial statistics change
This patch split the cpu_partial_free into 2 parts: cpu_partial_node, PCP refilling
times from node partial; and same name cpu_partial_free, PCP refilling times in
slab_free slow path. A new statistic 'cpu_partial_drain' is added to get PCP
drain to node partial times. These info are useful when do PCP tunning.

The slabinfo.c code is unchanged, since cpu_partial_node is not on slow path.

Signed-off-by: Alex Shi <alex.shi@intel.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-02-18 11:00:09 +02:00
Christoph Lameter 4de900b4d6 slub: include include for prefetch
Otherwise m68k breaks:

On Mon, 30 Jan 2012, Geert Uytterhoeven wrote:
> m68k/allmodconfig at http://kisskb.ellerman.id.au/kisskb/buildresult/5527349/
>
> mm/slub.c:274: error: implicit declaration of function 'prefetch'
>
> Sorry, didn't notice it earlier due to other build breakage in -next.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-02-10 14:47:39 +02:00
Christoph Lameter 66c4c35c6b slub: Do not hold slub_lock when calling sysfs_slab_add()
sysfs_slab_add() calls various sysfs functions that actually may
end up in userspace doing all sorts of things.

Release the slub_lock after adding the kmem_cache structure to the list.
At that point the address of the kmem_cache is not known so we are
guaranteed exlusive access to the following modifications to the
kmem_cache structure.

If the sysfs_slab_add fails then reacquire the slub_lock to
remove the kmem_cache structure from the list.

Cc: <stable@vger.kernel.org>	# 3.3+
Reported-by: Sasha Levin <levinsasha928@gmail.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-02-06 12:24:13 +02:00
Eric Dumazet 0ad9500e16 slub: prefetch next freelist pointer in slab_alloc()
Recycling a page is a problem, since freelist link chain is hot on
cpu(s) which freed objects, and possibly very cold on cpu currently
owning slab.

Adding a prefetch of cache line containing the pointer to next object in
slab_alloc() helps a lot in many workloads, in particular on assymetric
ones (allocations done on one cpu, frees on another cpus). Added cost is
three machine instructions only.

Examples on my dual socket quad core ht machine (Intel CPU E5540
@2.53GHz) (16 logical cpus, 2 memory nodes), 64bit kernel.

Before patch :

# perf stat -r 32 hackbench 50 process 4000 >/dev/null

 Performance counter stats for 'hackbench 50 process 4000' (32 runs):

     327577,471718 task-clock                #   15,821 CPUs utilized            ( +-  0,64% )
        28 866 491 context-switches          #    0,088 M/sec                    ( +-  1,80% )
         1 506 929 CPU-migrations            #    0,005 M/sec                    ( +-  3,24% )
           127 151 page-faults               #    0,000 M/sec                    ( +-  0,16% )
   829 399 813 448 cycles                    #    2,532 GHz                      ( +-  0,64% )
   580 664 691 740 stalled-cycles-frontend   #   70,01% frontend cycles idle     ( +-  0,71% )
   197 431 700 448 stalled-cycles-backend    #   23,80% backend  cycles idle     ( +-  1,03% )
   503 548 648 975 instructions              #    0,61  insns per cycle
                                             #    1,15  stalled cycles per insn  ( +-  0,46% )
    95 780 068 471 branches                  #  292,389 M/sec                    ( +-  0,48% )
     1 426 407 916 branch-misses             #    1,49% of all branches          ( +-  1,35% )

      20,705679994 seconds time elapsed                                          ( +-  0,64% )

After patch :

# perf stat -r 32 hackbench 50 process 4000 >/dev/null

 Performance counter stats for 'hackbench 50 process 4000' (32 runs):

     286236,542804 task-clock                #   15,786 CPUs utilized            ( +-  1,32% )
        19 703 372 context-switches          #    0,069 M/sec                    ( +-  4,99% )
         1 658 249 CPU-migrations            #    0,006 M/sec                    ( +-  6,62% )
           126 776 page-faults               #    0,000 M/sec                    ( +-  0,12% )
   724 636 593 213 cycles                    #    2,532 GHz                      ( +-  1,32% )
   499 320 714 837 stalled-cycles-frontend   #   68,91% frontend cycles idle     ( +-  1,47% )
   156 555 126 809 stalled-cycles-backend    #   21,60% backend  cycles idle     ( +-  2,22% )
   463 897 792 661 instructions              #    0,64  insns per cycle
                                             #    1,08  stalled cycles per insn  ( +-  0,94% )
    87 717 352 563 branches                  #  306,451 M/sec                    ( +-  0,99% )
       941 738 280 branch-misses             #    1,07% of all branches          ( +-  3,35% )

      18,132070670 seconds time elapsed                                          ( +-  1,30% )

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
CC: Matt Mackall <mpm@selenic.com>
CC: David Rientjes <rientjes@google.com>
CC: "Alex,Shi" <alex.shi@intel.com>
CC: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-01-24 21:53:57 +02:00
Heiko Carstens 2565409fc0 mm,x86,um: move CMPXCHG_DOUBLE config option
Move CMPXCHG_DOUBLE and rename it to HAVE_CMPXCHG_DOUBLE so architectures
can simply select the option if it is supported.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:03 -08:00
Heiko Carstens 43570fd2f4 mm,slub,x86: decouple size of struct page from CONFIG_CMPXCHG_LOCAL
While implementing cmpxchg_double() on s390 I realized that we don't set
CONFIG_CMPXCHG_LOCAL despite the fact that we have support for it.

However setting that option will increase the size of struct page by
eight bytes on 64 bit, which we certainly do not want.  Also, it doesn't
make sense that a present cpu feature should increase the size of struct
page.

Besides that it looks like the dependency to CMPXCHG_LOCAL is wrong and
that it should depend on CMPXCHG_DOUBLE instead.

This patch:

If an architecture supports CMPXCHG_LOCAL this shouldn't result
automatically in larger struct pages if the SLUB allocator is used.
Instead introduce a new config option "HAVE_ALIGNED_STRUCT_PAGE" which
can be selected if a double word aligned struct page is required.  Also
update x86 Kconfig so that it should work as before.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:03 -08:00
Linus Torvalds 6296e5d3c0 Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
  slub: disallow changing cpu_partial from userspace for debug caches
  slub: add missed accounting
  slub: Extract get_freelist from __slab_alloc
  slub: Switch per cpu partial page support off for debugging
  slub: fix a possible memleak in __slab_alloc()
  slub: fix slub_max_order Documentation
  slub: add missed accounting
  slab: add taint flag outputting to debug paths.
  slub: add taint flag outputting to debug paths
  slab: introduce slab_max_order kernel parameter
  slab: rename slab_break_gfp_order to slab_max_order
2012-01-11 18:52:23 -08:00
Pekka Enberg 5878cf431c Merge branch 'slab/urgent' into slab/for-linus 2012-01-11 21:11:29 +02:00
Stanislaw Gruszka fc8d8620d3 slub: min order when debug_guardpage_minorder > 0
Disable slub debug facilities and allocate slabs at minimal order when
debug_guardpage_minorder > 0 to increase probability to catch random
memory corruption by cpu exception.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:43 -08:00
David Rientjes 74ee4ef1f9 slub: disallow changing cpu_partial from userspace for debug caches
For caches with debugging enabled, "slub: Switch per cpu partial page
support off for debugging" changes cpu_partial to 0.  It shouldn't be
tunable from userspace for such caches, otherwise the same accounting
issues arise during validation.

This patch disallows tuning /sys/kernel/slab/cache/cpu_partial to be non-
zero for caches with debugging enabled.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-01-10 21:31:09 +02:00
Linus Torvalds 6b3da11b3c Merge branch 'for-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
* 'for-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: Remove irqsafe_cpu_xxx variants

Fix up conflict in arch/x86/include/asm/percpu.h due to clash with
cebef5beed ("x86: Fix and improve percpu_cmpxchg{8,16}b_double()")
which edited the (now removed) irqsafe_cpu_cmpxchg*_double code.
2012-01-09 13:08:28 -08:00
Jan Beulich cdcd629869 x86: Fix and improve cmpxchg_double{,_local}()
Just like the per-CPU ones they had several
problems/shortcomings:

Only the first memory operand was mentioned in the asm()
operands, and the 2x64-bit version didn't have a memory clobber
while the 2x32-bit one did. The former allowed the compiler to
not recognize the need to re-load the data in case it had it
cached in some register, while the latter was overly
destructive.

The types of the local copies of the old and new values were
incorrect (the types of the pointed-to variables should be used
here, to make sure the respective old/new variable types are
compatible).

The __dummy/__junk variables were pointless, given that local
copies of the inputs already existed (and can hence be used for
discarded outputs).

The 32-bit variant of cmpxchg_double_local() referenced
cmpxchg16b_local().

At once also:

 - change the return value type to what it really is: 'bool'
 - unify 32- and 64-bit variants
 - abstract out the common part of the 'normal' and 'local' variants

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/4F01F12A020000780006A19B@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-04 15:01:54 +01:00
Christoph Lameter 933393f58f percpu: Remove irqsafe_cpu_xxx variants
We simply say that regular this_cpu use must be safe regardless of
preemption and interrupt state.  That has no material change for x86
and s390 implementations of this_cpu operations.  However, arches that
do not provide their own implementation for this_cpu operations will
now get code generated that disables interrupts instead of preemption.

-tj: This is part of on-going percpu API cleanup.  For detailed
     discussion of the subject, please refer to the following thread.

     http://thread.gmane.org/gmane.linux.kernel/1222078

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
LKML-Reference: <alpine.DEB.2.00.1112221154380.11787@router.home>
2011-12-22 10:40:20 -08:00
Shaohua Li b13683d1cc slub: add missed accounting
With per-cpu partial list, slab is added to partial list first and then moved
to node list. The __slab_free() code path for add/remove_partial is almost
deprecated(except for slub debug). But we forget to account add/remove_partial
when move per-cpu partial pages to node list, so the statistics for such events
are always 0. Add corresponding accounting.

This is against the patch "slub: use correct parameter to add a page to
partial list tail"

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-12-13 22:27:09 +02:00
Christoph Lameter 213eeb9fd9 slub: Extract get_freelist from __slab_alloc
get_freelist retrieves free objects from the page freelist (put there by remote
frees) or deactivates a slab page if no more objects are available.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-12-13 22:17:10 +02:00
Christoph Lameter 8f1e33daed slub: Switch per cpu partial page support off for debugging
Eric saw an issue with accounting of slabs during validation. Its not
possible to determine accurately how many per cpu partial slabs exist at
any time so this switches off per cpu partial pages during debug.

Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-12-13 22:14:02 +02:00
Eric Dumazet 73736e0387 slub: fix a possible memleak in __slab_alloc()
Zhihua Che reported a possible memleak in slub allocator on
CONFIG_PREEMPT=y builds.

It is possible current thread migrates right before disabling irqs in
__slab_alloc(). We must check again c->freelist, and perform a normal
allocation instead of scratching c->freelist.

Many thanks to Zhihua Che for spotting this bug, introduced in 2.6.39

V2: Its also possible an IRQ freed one (or several) object(s) and
populated c->freelist, so its not a CONFIG_PREEMPT only problem.

Cc: <stable@vger.kernel.org>        [2.6.39+]
Reported-by: Zhihua Che <zhihua.che@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-12-13 22:11:21 +02:00
Shaohua Li 4c493a5a5c slub: add missed accounting
With per-cpu partial list, slab is added to partial list first and then moved
to node list. The __slab_free() code path for add/remove_partial is almost
deprecated(except for slub debug). But we forget to account add/remove_partial
when move per-cpu partial pages to node list, so the statistics for such events
are always 0. Add corresponding accounting.

This is against the patch "slub: use correct parameter to add a page to
partial list tail"

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-11-27 22:08:15 +02:00
Pekka Enberg 42616cacf8 Merge branch 'slab/urgent' into slab/next 2011-11-27 22:08:03 +02:00
Eric Dumazet bc6697d8a5 slub: avoid potential NULL dereference or corruption
show_slab_objects() can trigger NULL dereferences or memory corruption.

Another cpu can change its c->page to NULL or c->node to NUMA_NO_NODE
while we use them.

Use ACCESS_ONCE(c->page) and ACCESS_ONCE(c->node) to make sure this
cannot happen.

Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-11-24 08:44:19 +02:00
Christoph Lameter 42d623a8cd slub: use irqsafe_cpu_cmpxchg for put_cpu_partial
The cmpxchg must be irq safe. The fallback for this_cpu_cmpxchg only
disables preemption which results in per cpu partial page operation
potentially failing on non x86 platforms.

This patch fixes the following problem reported by Christian Kujau:

  I seem to hit it with heavy disk & cpu IO is in progress on this
  PowerBook
  G4. Full dmesg & .config: http://nerdbynature.de/bits/3.2.0-rc1/oops/

  I've enabled some debug options and now it really points to slub.c:2166

    http://nerdbynature.de/bits/3.2.0-rc1/oops/oops4m.jpg

  With debug options enabled I'm currently in the xmon debugger, not sure
  what to make of it yet, I'll try to get something useful out of it :)

Reported-by: Christian Kujau <lists@nerdbynature.de>
Tested-by: Christian Kujau <lists@nerdbynature.de>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-11-24 08:44:14 +02:00
Dave Jones 265d47e711 slub: add taint flag outputting to debug paths
When we get corruption reports, it's useful to see if the kernel was
tainted, to rule out problems we can't do anything about.

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-11-16 21:14:40 +02:00