Commit Graph

420 Commits

Author SHA1 Message Date
Shaohua Li
130655ef09 slub: add slab with one free object to partial list tail
The slab has just one free object, adding it to partial list head doesn't make
sense. And it can cause lock contentation. For example,
1. CPU takes the slab from partial list
2. fetch an object
3. switch to another slab
4. free an object, then the slab is added to partial list again
In this way n->list_lock will be heavily contended.
In fact, Alex had a hackbench regression. 3.1-rc1 performance drops about 70%
against 3.0. This patch fixes it.

Acked-by: Christoph Lameter <cl@linux.com>
Reported-by: Alex Shi <alex.shi@intel.com>
Signed-off-by: Shaohua Li <shli@kernel.org>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-08-27 11:58:59 +03:00
Christoph Lameter
81107188f1 slub: Fix partial count comparison confusion
deactivate_slab() has the comparison if more than the minimum number of
partial pages are in the partial list wrong. An effect of this may be that
empty pages are not freed from deactivate_slab(). The result could be an
OOM due to growth of the partial slabs per node. Frees mostly occur from
__slab_free which is okay so this would only affect use cases where a lot
of switching around of per cpu slabs occur.

Switching per cpu slabs occurs with high frequency if debugging options are
enabled.

Reported-and-tested-by: Xiaotian Feng <xtfeng@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-08-09 21:12:31 +03:00
Akinobu Mita
ef62fb32b7 slub: fix check_bytes() for slub debugging
The check_bytes() function is used by slub debugging.  It returns a pointer
to the first unmatching byte for a character in the given memory area.

If the character for matching byte is greater than 0x80, check_bytes()
doesn't work.  Becuase 64-bit pattern is generated as below.

	value64 = value | value << 8 | value << 16 | value << 24;
	value64 = value64 | value64 << 32;

The integer promotions are performed and sign-extended as the type of value
is u8.  The upper 32 bits of value64 is 0xffffffff in the first line, and
the second line has no effect.

This fixes the 64-bit pattern generation.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Matt Mackall <mpm@selenic.com>
Reviewed-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-08-09 16:37:48 +03:00
Christoph Lameter
6fbabb20fa slub: Fix full list corruption if debugging is on
When a slab is freed by __slab_free() and the slab can only contain a
single object ever then it was full (and therefore not on the partial
lists but on the full list in the debug case) before we reached
slab_empty.

This caused the following full list corruption when SLUB debugging was enabled:

  [ 5913.233035] ------------[ cut here ]------------
  [ 5913.233097] WARNING: at lib/list_debug.c:53 __list_del_entry+0x8d/0x98()
  [ 5913.233101] Hardware name: Adamo 13
  [ 5913.233105] list_del corruption. prev->next should be ffffea000434fd20, but was ffffea0004199520
  [ 5913.233108] Modules linked in: nfs fscache fuse ebtable_nat ebtables ppdev parport_pc lp parport ipt_MASQUERADE iptable_nat nf_nat nfsd lockd nfs_acl auth_rpcgss xt_CHECKSUM sunrpc iptable_mangle bridge stp llc cpufreq_ondemand acpi_cpufreq freq_table mperf ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables rfcomm bnep arc4 iwlagn snd_hda_codec_hdmi snd_hda_codec_idt snd_hda_intel btusb mac80211 snd_hda_codec bluetooth snd_hwdep snd_seq snd_seq_device snd_pcm usb_debug dell_wmi sparse_keymap cdc_ether usbnet cdc_acm uvcvideo cdc_wdm mii cfg80211 snd_timer dell_laptop videodev dcdbas snd microcode v4l2_compat_ioctl32 soundcore joydev tg3 pcspkr snd_page_alloc iTCO_wdt i2c_i801 rfkill iTCO_vendor_support wmi virtio_net kvm_intel kvm ipv6 xts gf128mul dm_crypt i915 drm_kms_helper drm i2c_algo_bit i2c_core video [last unloaded: scsi_wait_scan]
  [ 5913.233213] Pid: 0, comm: swapper Not tainted 3.0.0+ #127
  [ 5913.233213] Call Trace:
  [ 5913.233213]  <IRQ>  [<ffffffff8105df18>] warn_slowpath_common+0x83/0x9b
  [ 5913.233213]  [<ffffffff8105dfd3>] warn_slowpath_fmt+0x46/0x48
  [ 5913.233213]  [<ffffffff8127e7c1>] __list_del_entry+0x8d/0x98
  [ 5913.233213]  [<ffffffff8127e7da>] list_del+0xe/0x2d
  [ 5913.233213]  [<ffffffff814e0430>] __slab_free+0x1db/0x235
  [ 5913.233213]  [<ffffffff811706ab>] ? bvec_free_bs+0x35/0x37
  [ 5913.233213]  [<ffffffff811706ab>] ? bvec_free_bs+0x35/0x37
  [ 5913.233213]  [<ffffffff811706ab>] ? bvec_free_bs+0x35/0x37
  [ 5913.233213]  [<ffffffff81133085>] kmem_cache_free+0x88/0x102
  [ 5913.233213]  [<ffffffff811706ab>] bvec_free_bs+0x35/0x37
  [ 5913.233213]  [<ffffffff811706e1>] bio_free+0x34/0x64
  [ 5913.233213]  [<ffffffff813dc390>] dm_bio_destructor+0x12/0x14
  [ 5913.233213]  [<ffffffff8116fef6>] bio_put+0x2b/0x2d
  [ 5913.233213]  [<ffffffff813dccab>] clone_endio+0x9e/0xb4
  [ 5913.233213]  [<ffffffff8116f7dd>] bio_endio+0x2d/0x2f
  [ 5913.233213]  [<ffffffffa00148da>] crypt_dec_pending+0x5c/0x8b [dm_crypt]
  [ 5913.233213]  [<ffffffffa00150a9>] crypt_endio+0x78/0x81 [dm_crypt]

[ Full discussion here: https://lkml.org/lkml/2011/8/4/375 ]

Make sure that we remove such a slab also from the full lists.

Reported-and-tested-by: Dave Jones <davej@redhat.com>
Reported-and-tested-by: Xiaotian Feng <xtfeng@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-08-09 16:36:02 +03:00
Linus Torvalds
c11abbbaa3 Merge branch 'slub/lockless' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6
* 'slub/lockless' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6: (21 commits)
  slub: When allocating a new slab also prep the first object
  slub: disable interrupts in cmpxchg_double_slab when falling back to pagelock
  Avoid duplicate _count variables in page_struct
  Revert "SLUB: Fix build breakage in linux/mm_types.h"
  SLUB: Fix build breakage in linux/mm_types.h
  slub: slabinfo update for cmpxchg handling
  slub: Not necessary to check for empty slab on load_freelist
  slub: fast release on full slab
  slub: Add statistics for the case that the current slab does not match the node
  slub: Get rid of the another_slab label
  slub: Avoid disabling interrupts in free slowpath
  slub: Disable interrupts in free_debug processing
  slub: Invert locking and avoid slab lock
  slub: Rework allocator fastpaths
  slub: Pass kmem_cache struct to lock and freeze slab
  slub: explicit list_lock taking
  slub: Add cmpxchg_double_slab()
  mm: Rearrange struct page
  slub: Move page->frozen handling near where the page->freelist handling occurs
  slub: Do not use frozen page flag but a bit in the page counters
  ...
2011-07-30 08:21:48 -10:00
Linus Torvalds
d3ec4844d4 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (43 commits)
  fs: Merge split strings
  treewide: fix potentially dangerous trailing ';' in #defined values/expressions
  uwb: Fix misspelling of neighbourhood in comment
  net, netfilter: Remove redundant goto in ebt_ulog_packet
  trivial: don't touch files that are removed in the staging tree
  lib/vsprintf: replace link to Draft by final RFC number
  doc: Kconfig: `to be' -> `be'
  doc: Kconfig: Typo: square -> squared
  doc: Konfig: Documentation/power/{pm => apm-acpi}.txt
  drivers/net: static should be at beginning of declaration
  drivers/media: static should be at beginning of declaration
  drivers/i2c: static should be at beginning of declaration
  XTENSA: static should be at beginning of declaration
  SH: static should be at beginning of declaration
  MIPS: static should be at beginning of declaration
  ARM: static should be at beginning of declaration
  rcu: treewide: Do not use rcu_read_lock_held when calling rcu_dereference_check
  Update my e-mail address
  PCIe ASPM: forcedly -> forcibly
  gma500: push through device driver tree
  ...

Fix up trivial conflicts:
 - arch/arm/mach-ep93xx/dma-m2p.c (deleted)
 - drivers/gpio/gpio-ep93xx.c (renamed and context nearby)
 - drivers/net/r8169.c (just context changes)
2011-07-25 13:56:39 -07:00
Christoph Lameter
9e577e8b46 slub: When allocating a new slab also prep the first object
We need to branch to the debug code for the first object if we allocate
a new slab otherwise the first object will be marked wrongly as inactive.

Tested-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-25 20:58:19 +03:00
Linus Torvalds
f99b7880cb Merge branch 'slab-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6
* 'slab-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
  slab: fix DEBUG_SLAB warning
  slab: shrink sizeof(struct kmem_cache)
  slab: fix DEBUG_SLAB build
  SLUB: Fix missing <linux/stacktrace.h> include
  slub: reduce overhead of slub_debug
  slub: Add method to verify memory is not freed
  slub: Enable backtrace for create/delete points
  slab allocators: Provide generic description of alignment defines
  slab, slub, slob: Unify alignment definition
  slob/lockdep: Fix gfp flags passed to lockdep
2011-07-22 12:44:30 -07:00
Phil Carmody
497888cf69 treewide: fix potentially dangerous trailing ';' in #defined values/expressions
All these are instances of
  #define NAME value;
or
  #define NAME(params_opt) value;

These of course fail to build when used in contexts like
  if(foo $OP NAME)
  while(bar $OP NAME)
and may silently generate the wrong code in contexts such as
  foo = NAME + 1;    /* foo = value; + 1; */
  bar = NAME - 1;    /* bar = value; - 1; */
  baz = NAME & quux; /* baz = value; & quux; */

Reported on comp.lang.c,
Message-ID: <ab0d55fe-25e5-482b-811e-c475aa6065c3@c29g2000yqd.googlegroups.com>
Initial analysis of the dangers provided by Keith Thompson in that thread.

There are many more instances of more complicated macros having unnecessary
trailing semicolons, but this pile seems to be all of the cases of simple
values suffering from the problem. (Thus things that are likely to be found
in one of the contexts above, more complicated ones aren't.)

Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-07-21 14:10:00 +02:00
Christoph Lameter
1d07171c5e slub: disable interrupts in cmpxchg_double_slab when falling back to pagelock
Split cmpxchg_double_slab into two functions. One for the case where we know that
interrupts are disabled (and therefore the fallback does not need to disable
interrupts) and one for the other cases where fallback will also disable interrupts.

This fixes the issue that __slab_free called cmpxchg_double_slab in some scenarios
without disabling interrupts.

Tested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-18 15:17:02 +03:00
Pekka Enberg
bfa71457a0 SLUB: Fix missing <linux/stacktrace.h> include
This fixes the following build breakage commit d6543e3 ("slub: Enable backtrace
for create/delete points"):

  CC      mm/slub.o
mm/slub.c: In function ‘set_track’:
mm/slub.c:428: error: storage size of ‘trace’ isn’t known
mm/slub.c:435: error: implicit declaration of function ‘save_stack_trace’
mm/slub.c:428: warning: unused variable ‘trace’
make[1]: *** [mm/slub.o] Error 1
make: *** [mm/slub.o] Error 2

Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-07 22:47:01 +03:00
Marcin Slusarz
c4089f98e9 slub: reduce overhead of slub_debug
slub checks for poison one byte by one, which is highly inefficient
and shows up frequently as a highest cpu-eater in perf top.

Joining reads gives nice speedup:

(Compiling some project with different options)
                                 make -j12    make clean
slub_debug disabled:             1m 27s       1.2 s
slub_debug enabled:              1m 46s       7.6 s
slub_debug enabled + this patch: 1m 33s       3.2 s

check_bytes still shows up high, but not always at the top.

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: linux-mm@kvack.org
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-07 22:44:45 +03:00
Ben Greear
d18a90dd85 slub: Add method to verify memory is not freed
This is for tracking down suspect memory usage.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-07 22:17:08 +03:00
Ben Greear
d6543e3935 slub: Enable backtrace for create/delete points
This patch attempts to grab a backtrace for the creation
and deletion points of the slub object.  When a fault is
detected, we can then get a better idea of where the item
was deleted.

Example output from debugging some funky nfs/rpc behaviour:

=============================================================================
BUG kmalloc-64: Object is on free-list
-----------------------------------------------------------------------------

INFO: Allocated in rpcb_getport_async+0x39c/0x5a5 [sunrpc] age=381 cpu=3 pid=3750
       __slab_alloc+0x348/0x3ba
       kmem_cache_alloc_trace+0x67/0xe7
       rpcb_getport_async+0x39c/0x5a5 [sunrpc]
       call_bind+0x70/0x75 [sunrpc]
       __rpc_execute+0x78/0x24b [sunrpc]
       rpc_execute+0x3d/0x42 [sunrpc]
       rpc_run_task+0x79/0x81 [sunrpc]
       rpc_call_sync+0x3f/0x60 [sunrpc]
       rpc_ping+0x42/0x58 [sunrpc]
       rpc_create+0x4aa/0x527 [sunrpc]
       nfs_create_rpc_client+0xb1/0xf6 [nfs]
       nfs_init_client+0x3b/0x7d [nfs]
       nfs_get_client+0x453/0x5ab [nfs]
       nfs_create_server+0x10b/0x437 [nfs]
       nfs_fs_mount+0x4ca/0x708 [nfs]
       mount_fs+0x6b/0x152
INFO: Freed in rpcb_map_release+0x3f/0x44 [sunrpc] age=30 cpu=2 pid=29049
       __slab_free+0x57/0x150
       kfree+0x107/0x13a
       rpcb_map_release+0x3f/0x44 [sunrpc]
       rpc_release_calldata+0x12/0x14 [sunrpc]
       rpc_free_task+0x59/0x61 [sunrpc]
       rpc_final_put_task+0x82/0x8a [sunrpc]
       __rpc_execute+0x23c/0x24b [sunrpc]
       rpc_async_schedule+0x10/0x12 [sunrpc]
       process_one_work+0x230/0x41d
       worker_thread+0x133/0x217
       kthread+0x7d/0x85
       kernel_thread_helper+0x4/0x10
INFO: Slab 0xffffea00029aa470 objects=20 used=9 fp=0xffff8800be7830d8 flags=0x20000000004081
INFO: Object 0xffff8800be7830d8 @offset=4312 fp=0xffff8800be7827a8

Bytes b4 0xffff8800be7830c8:  87 a8 96 00 01 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a .�......ZZZZZZZZ
 Object 0xffff8800be7830d8:  6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
 Object 0xffff8800be7830e8:  6b 6b 6b 6b 01 08 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkk..kkkkkkkkkk
 Object 0xffff8800be7830f8:  6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
 Object 0xffff8800be783108:  6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkk�
 Redzone 0xffff8800be783118:  bb bb bb bb bb bb bb bb                         �������������
 Padding 0xffff8800be783258:  5a 5a 5a 5a 5a 5a 5a 5a                         ZZZZZZZZ
Pid: 29049, comm: kworker/2:2 Not tainted 3.0.0-rc4+ #8
Call Trace:
 [<ffffffff811055c3>] print_trailer+0x131/0x13a
 [<ffffffff81105601>] object_err+0x35/0x3e
 [<ffffffff8110746f>] verify_mem_not_deleted+0x7a/0xb7
 [<ffffffffa02851b5>] rpcb_getport_done+0x23/0x126 [sunrpc]
 [<ffffffffa027d0ba>] rpc_exit_task+0x3f/0x6d [sunrpc]
 [<ffffffffa027d4ab>] __rpc_execute+0x78/0x24b [sunrpc]
 [<ffffffffa027d6c0>] ? rpc_execute+0x42/0x42 [sunrpc]
 [<ffffffffa027d6d0>] rpc_async_schedule+0x10/0x12 [sunrpc]
 [<ffffffff810611b7>] process_one_work+0x230/0x41d
 [<ffffffff81061102>] ? process_one_work+0x17b/0x41d
 [<ffffffff81063613>] worker_thread+0x133/0x217
 [<ffffffff810634e0>] ? manage_workers+0x191/0x191
 [<ffffffff81066e10>] kthread+0x7d/0x85
 [<ffffffff81485924>] kernel_thread_helper+0x4/0x10
 [<ffffffff8147eb18>] ? retint_restore_args+0x13/0x13
 [<ffffffff81066d93>] ? __init_kthread_worker+0x56/0x56
 [<ffffffff81485920>] ? gs_change+0x13/0x13

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-07 22:17:03 +03:00
Christoph Lameter
4eade540fc slub: Not necessary to check for empty slab on load_freelist
load_freelist is now only branched to only if there are objects available.
So no need to check the object variable for NULL.

Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:57 +03:00
Christoph Lameter
03e404af26 slub: fast release on full slab
Make deactivation occur implicitly while checking out the current freelist.

This avoids one cmpxchg operation on a slab that is now fully in use.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:57 +03:00
Christoph Lameter
e36a2652d7 slub: Add statistics for the case that the current slab does not match the node
Slub reloads the per cpu slab if the page does not satisfy the NUMA condition. Track
those reloads since doing so has a performance impact.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:56 +03:00
Christoph Lameter
fc59c05306 slub: Get rid of the another_slab label
We can avoid deactivate slab in special cases if we do the
deactivation of slabs in each code flow that leads to new_slab.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:56 +03:00
Christoph Lameter
80f08c191f slub: Avoid disabling interrupts in free slowpath
Disabling interrupts can be avoided now. However, list operation still require
disabling interrupts since allocations can occur from interrupt
contexts and there is no way to perform atomic list operations.

The acquition of the list_lock therefore has to disable interrupts as well.

Dropping interrupt handling significantly simplifies the slowpath.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:56 +03:00
Christoph Lameter
5c2e4bbbd6 slub: Disable interrupts in free_debug processing
We will be calling free_debug_processing with interrupts disabled
in some case when the later patches are applied. Some of the
functions called by free_debug_processing expect interrupts to be
off.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:55 +03:00
Christoph Lameter
881db7fb03 slub: Invert locking and avoid slab lock
Locking slabs is no longer necesary if the arch supports cmpxchg operations
and if no debuggin features are used on a slab. If the arch does not support
cmpxchg then we fallback to use the slab lock to do a cmpxchg like operation.

The patch also changes the lock order. Slab locks are subsumed to the node lock
now. With that approach slab_trylocking is no longer necessary.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:55 +03:00
Christoph Lameter
2cfb7455d2 slub: Rework allocator fastpaths
Rework the allocation paths so that updates of the page freelist, frozen state
and number of objects use cmpxchg_double_slab().

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:54 +03:00
Christoph Lameter
61728d1efc slub: Pass kmem_cache struct to lock and freeze slab
We need more information about the slab for the cmpxchg implementation.

Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:54 +03:00
Christoph Lameter
5cc6eee8a8 slub: explicit list_lock taking
The allocator fastpath rework does change the usage of the list_lock.
Remove the list_lock processing from the functions that hide them from the
critical sections and move them into those critical sections.

This in turn simplifies the support functions (no __ variant needed anymore)
and simplifies the lock handling on bootstrap.

Inline add_partial since it becomes pretty simple.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:54 +03:00
Christoph Lameter
b789ef518b slub: Add cmpxchg_double_slab()
Add a function that operates on the second doubleword in the page struct
and manipulates the object counters, the freelist and the frozen attribute.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:53 +03:00
Christoph Lameter
8cb0a5068f slub: Move page->frozen handling near where the page->freelist handling occurs
This is necessary because the frozen bit has to be handled in the same cmpxchg_double
with the freelist and the counters.

Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:53 +03:00
Christoph Lameter
50d5c41cd1 slub: Do not use frozen page flag but a bit in the page counters
Do not use a page flag for the frozen bit. It needs to be part
of the state that is handled with cmpxchg_double(). So use a bit
in the counter struct in the page struct for that purpose.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:52 +03:00
Christoph Lameter
7e0528dadc slub: Push irq disable into allocate_slab()
Do the irq handling in allocate_slab() instead of __slab_alloc().

__slab_alloc() is already cluttered and allocate_slab() is already
fiddling around with gfp flags.

v6->v7:
	Only increment ORDER_FALLBACK if we get a page during fallback

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-02 13:26:52 +03:00
Chris Metcalf
d4d84fef6d slub: always align cpu_slab to honor cmpxchg_double requirement
On an architecture without CMPXCHG_LOCAL but with DEBUG_VM enabled,
the VM_BUG_ON() in __pcpu_double_call_return_bool() will cause an early
panic during boot unless we always align cpu_slab properly.

In principle we could remove the alignment-testing VM_BUG_ON() for
architectures that don't have CMPXCHG_LOCAL, but leaving it in means
that new code will tend not to break x86 even if it is introduced
on another platform, and it's low cost to require alignment.

Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-06-03 19:33:49 +03:00
Linus Torvalds
49a78d085f slub: remove no-longer used 'unlock_out' label
Commit a71ae47a2c ("slub: Fix double bit unlock in debug mode")
removed the only goto to this label, resulting in

  mm/slub.c: In function '__slab_alloc':
  mm/slub.c:1834: warning: label 'unlock_out' defined but not used

fixed trivially by the removal of the label itself too.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 18:06:54 -07:00
Christoph Lameter
a71ae47a2c slub: Fix double bit unlock in debug mode
Commit 442b06bcea ("slub: Remove node check in slab_free") added a
call to deactivate_slab() in the debug case in __slab_alloc(), which
unlocks the current slab used for allocation.  Going to the label
'unlock_out' then does it again.

Also, in the debug case we do not need all the other processing that the
'unlock_out' path does.  We always fall back to the slow path in the
debug case.  So the tid update is useless.

Similarly, ALLOC_SLOWPATH would just be incremented for all allocations.
Also a pretty useless thing.

So simply restore irq flags and return the object.

Signed-off-by: Christoph Lameter <cl@linux.com>
Reported-and-bisected-by: James Morris <jmorris@namei.org>
Reported-by: Ingo Molnar <mingo@elte.hu>
Reported-by: Jens Axboe <jaxboe@fusionio.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:38:24 -07:00
Pekka Enberg
bfb91fb650 Merge branch 'slab/next' into for-linus
Conflicts:
	mm/slub.c
2011-05-23 19:50:39 +03:00
Christoph Lameter
442b06bcea slub: Remove node check in slab_free
We can set the page pointing in the percpu structure to
NULL to have the same effect as setting c->node to NUMA_NO_NODE.

Gets rid of one check in slab_free() that was only used for
forcing the slab_free to the slowpath for debugging.

We still need to set c->node to NUMA_NO_NODE to force the
slab_alloc() fastpath to the slowpath in case of debugging.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-05-21 12:53:53 +03:00
David Rientjes
bd07d87fd4 slub: avoid label inside conditional
Jumping to a label inside a conditional is considered poor style,
especially considering the current organization of __slab_alloc().

This removes the 'load_from_page' label and just duplicates the three
lines of code that it uses:

	c->node = page_to_nid(page);
	c->page = page;
	goto load_freelist;

since it's probably not worth making this a separate helper function.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-05-17 22:19:00 +03:00
Christoph Lameter
1393d9a185 slub: Make CONFIG_DEBUG_PAGE_ALLOC work with new fastpath
Fastpath can do a speculative access to a page that CONFIG_DEBUG_PAGE_ALLOC may have
marked as invalid to retrieve the pointer to the next free object.

Use probe_kernel_read in that case in order not to cause a page fault.

Cc: <stable@kernel.org> # 38.x
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-05-17 22:18:55 +03:00
Christoph Lameter
6332aa9d25 slub: Avoid warning for !CONFIG_SLUB_DEBUG
Move the #ifdef so that get_map is only defined if CONFIG_SLUB_DEBUG is defined.

Reported-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-05-17 22:16:08 +03:00
Christoph Lameter
1759415e63 slub: Remove CONFIG_CMPXCHG_LOCAL ifdeffery
Remove the #ifdefs. This means that the irqsafe_cpu_cmpxchg_double() is used
everywhere.

There may be performance implications since:

A. We now have to manage a transaction ID for all arches

B. The interrupt holdoff for arches not supporting CONFIG_CMPXCHG_LOCAL is reduced
to a very short irqoff section.

There are no multiple irqoff/irqon sequences as a result of this change. Even in the fallback
case we only have to do one disable and enable like before.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-05-07 20:25:38 +03:00
Thomas Gleixner
30106b8ce2 slub: Fix the lockless code on 32-bit platforms with no 64-bit cmpxchg
The SLUB allocator use of the cmpxchg_double logic was wrong: it
actually needs the irq-safe one.

That happens automatically when we use the native unlocked 'cmpxchg8b'
instruction, but when compiling the kernel for older x86 CPUs that do
not support that instruction, we fall back to the generic emulation
code.

And if you don't specify that you want the irq-safe version, the generic
code ends up just open-coding the cmpxchg8b equivalent without any
protection against interrupts or preemption.  Which definitely doesn't
work for SLUB.

This was reported by Werner Landgraf <w.landgraf@ru.ru>, who saw
instability with his distro-kernel that was compiled to support pretty
much everything under the sun.  Most big Linux distributions tend to
compile for PPro and later, and would never have noticed this problem.

This also fixes the prototypes for the irqsafe cmpxchg_double functions
to use 'bool' like they should.

[ Btw, that whole "generic code defaults to no protection" design just
  sounds stupid - if the code needs no protection, there is no reason to
  use "cmpxchg_double" to begin with.  So we should probably just remove
  the unprotected version entirely as pointless.   - Linus ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reported-and-tested-by: werner <w.landgraf@ru.ru>
Acked-and-tested-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1105041539050.3005@ionos
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-04 14:20:20 -07:00
Christoph Lameter
8dc16c6c04 slub: Move debug handlign in __slab_free
Its easier to read if its with the check for debugging flags.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-04-17 14:03:20 +03:00
Christoph Lameter
dc1fb7f436 slub: Move node determination out of hotpath
If the node does not change then there is no need to recalculate
the node from the page struct. So move the node determination
into the places where we acquire a new slab page.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-04-17 14:03:20 +03:00
Christoph Lameter
01ad8a7bc2 slub: Eliminate repeated use of c->page through a new page variable
__slab_alloc is full of "c->page" repeats. Lets just use one local variable
named "page" for this. Also avoids the need to a have another variable
called "new".

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-04-17 14:03:19 +03:00
Christoph Lameter
5f80b13ae4 slub: get_map() function to establish map of free objects in a slab
The bit map of free objects in a slab page is determined in various functions
if debugging is enabled.

Provide a common function for that purpose.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-04-17 14:03:19 +03:00
Christoph Lameter
33de04ec4c slub: Use NUMA_NO_NODE in get_partial
A -1 was leftover during the conversion.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-04-17 14:03:19 +03:00
Li Zefan
607bf324ab slub: Fix a typo in config name
There's no config named SLAB_DEBUG, and it should be a typo
of SLUB_DEBUG.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-04-12 22:27:27 +03:00
Lucas De Marchi
25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
Christoph Lameter
b8c4c96ed4 SLUB: Write to per cpu data when allocating it
It turns out that the cmpxchg16b emulation has to access vmalloced
percpu memory with interrupts disabled. If the memory has never
been touched before then the fault necessary to establish the
mapping will not to occur and the kernel will fail on boot.

Fix that by reusing the CONFIG_PREEMPT code that writes the
cpu number into a field on every cpu. Writing to the per cpu
area before causes the mapping to be established before we get
to a cmpxchg16b emulation.

Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-03-24 21:53:07 +02:00
Thomas Gleixner
f9b615de46 slub: Fix debugobjects with lockless fastpath
On Thu, 24 Mar 2011, Ingo Molnar wrote:
> RIP: 0010:[<ffffffff810570a9>]  [<ffffffff810570a9>] get_next_timer_interrupt+0x119/0x260

That's a typical timer crash, but you were unable to debug it with
debugobjects because commit d3f661d6 broke those.

Cc: Christoph Lameter <cl@linux.com>
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-03-24 21:26:46 +02:00
Christoph Lameter
4fdccdfbb4 slub: Add statistics for this_cmpxchg_double failures
Add some statistics for debugging.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-03-22 20:48:04 +02:00
Christoph Lameter
2fd66c517d slub: Add missing irq restore for the OOM path
OOM path is missing the irq restore in the CONFIG_CMPXCHG_LOCAL case.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-03-22 20:48:04 +02:00
Pekka Enberg
e8c500c2b6 Merge branch 'slub/lockless' into for-linus
Conflicts:
	include/linux/slub_def.h
2011-03-20 18:13:26 +02:00