linux/mm
Linus Torvalds 00e962c540 Revert "SLUB: Alternate fast paths using cmpxchg_local"
This reverts commit 1f84260c8c, which is
suspected to be the reason for some very occasional and hard-to-trigger
crashes that usually look related to memory allocation (mostly reported
in networking, but since that's generally the most common source of
shortlived allocations - and allocations in interrupt contexts - that in
itself is not a big clue).

See for example
	http://bugzilla.kernel.org/show_bug.cgi?id=9973
	http://lkml.org/lkml/2008/2/19/278
etc.

One promising suspicion for what the root cause of bug is (which also
explains why it's so hard to trigger in practice) came from Eric
Dumazet:

   "I wonder how SLUB_FASTPATH is supposed to work, since it is affected
    by a classical ABA problem of lockless algo.

    cmpxchg_local(&c->freelist, object, object[c->offset]) can succeed,
    while an interrupt came (on this cpu), and several allocations were
    done, and one free was performed at the end of this interruption, so
    'object' was recycled.

    c->freelist can then contain the previous value (object), but
    object[c->offset] was changed by IRQ.

    We then put back in freelist an already allocated object."

but another reason for the revert is simply that everybody agrees that
this code was the main suspect just by virtue of the pattern of oopses.

Cc: Torsten Kaiser <just.for.lkml@googlemail.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-19 09:08:49 -08:00
..
Kconfig sh: Bump number of quicklists for SH-5. 2008-01-28 13:18:55 +09:00
Makefile Memory controller: cgroups setup 2008-02-07 08:42:18 -08:00
allocpercpu.c PERCPU : __percpu_alloc_mask() can dynamically size percpu_data storage 2008-02-06 10:41:04 -08:00
backing-dev.c mm/backing-dev.c: fix percpu_counter_destroy call bug in bdi_init 2007-12-05 09:21:18 -08:00
bootmem.c Introduce flags for reserve_bootmem() 2008-02-07 08:42:25 -08:00
bounce.c block: Initial support for data-less (or empty) barrier support 2007-10-16 11:03:56 +02:00
dmapool.c pool: Improve memory usage for devices which can't cross boundaries 2007-12-04 10:39:58 -05:00
fadvise.c check ADVICE of fadvise64_64 even if get_xip_page is given 2008-02-05 09:44:19 -08:00
filemap.c remove final fastcall users 2008-02-13 16:21:18 -08:00
filemap_xip.c Use pgoff_t instead of unsigned long 2008-02-08 09:22:32 -08:00
fremap.c sys_remap_file_pages: fix ->vm_file accounting 2008-02-05 09:44:07 -08:00
highmem.c mm: remove fastcall from mm/ 2008-02-05 09:44:18 -08:00
hugetlb.c hugetlb: fix overcommit locking 2008-02-13 16:21:18 -08:00
internal.h set_page_refcounted() VM_BUG_ON fix 2008-02-05 09:44:19 -08:00
madvise.c speed up madvise_need_mmap_write() usage 2007-07-16 09:05:36 -07:00
memcontrol.c memcontrol: add vm_match_cgroup() 2008-02-09 11:08:33 -08:00
memory.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86 2008-02-14 21:23:19 -08:00
memory_hotplug.c Page allocator: clean up pcp draining functions 2008-02-05 09:44:17 -08:00
mempolicy.c d_path: Make seq_path() use a struct path argument 2008-02-14 21:17:08 -08:00
mempool.c spelling fixes: mm/ 2007-10-20 01:27:18 +02:00
migrate.c bugfix for memory cgroup controller: migration under memory controller fix 2008-02-07 08:42:19 -08:00
mincore.c [PATCH] mincore: vma crossing fix 2007-02-15 09:57:03 -08:00
mlock.c do not limit locked memory when RLIMIT_MEMLOCK is RLIM_INFINITY 2007-07-16 09:05:37 -07:00
mmap.c mm: special mapping nopage 2008-02-08 18:57:39 -08:00
mmzone.c [PATCH] remove EXPORT_UNUSED_SYMBOL'ed symbols 2006-12-07 08:39:44 -08:00
mprotect.c fix mprotect vma_wants_writenotify prot 2007-10-23 08:32:06 -07:00
mremap.c sparse pointer use of zero as null 2007-10-18 14:37:31 -07:00
msync.c Detach sched.h from mm.h 2007-05-21 09:18:19 -07:00
nommu.c nommu: add new vmalloc_user() and remap_vmalloc_range() interfaces. 2008-02-05 09:44:21 -08:00
oom_kill.c oom: add sysctl to enable task memory dump 2008-02-07 08:42:19 -08:00
page-writeback.c writeback: speed up writeback of big dirty files 2008-02-05 09:44:19 -08:00
page_alloc.c misc: removal of final callers using fastcall 2008-02-08 09:22:31 -08:00
page_io.c mm: fix PageUptodate data race 2008-02-05 09:44:19 -08:00
page_isolation.c memory hotremove: unset migrate type "ISOLATE" after removal 2007-11-14 18:45:38 -08:00
pagewalk.c maps4: introduce a generic page walker 2008-02-05 09:44:16 -08:00
pdflush.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
prio_tree.c spelling fixes: mm/ 2007-10-20 01:27:18 +02:00
quicklist.c quicklists: Only consider memory that can be used with GFP_KERNEL 2008-01-14 08:52:22 -08:00
readahead.c mm: bdi init hooks 2007-10-17 08:42:45 -07:00
rmap.c memcontrol: add vm_match_cgroup() 2008-02-09 11:08:33 -08:00
shmem.c mount-options-fix-tmpfs-fix 2008-02-08 09:22:41 -08:00
shmem_acl.c [PATCH] Fix typos in mm/shmem_acl.c 2006-10-11 11:14:23 -07:00
slab.c slab: avoid double initialization & do initialization in 1 place 2008-02-14 15:30:01 -08:00
slob.c slob: reduce external fragmentation by using three free lists 2008-02-05 09:44:19 -08:00
slub.c Revert "SLUB: Alternate fast paths using cmpxchg_local" 2008-02-19 09:08:49 -08:00
sparse-vmemmap.c memory hotplug fix: fix section mismatch in vmammap_allock_block() 2007-11-29 09:24:54 -08:00
sparse.c mm: fix section mismatch warning in sparse.c 2008-02-05 09:44:19 -08:00
swap.c Memory controller: add per cgroup LRU and reclaim 2008-02-07 08:42:18 -08:00
swap_state.c memcgroup: revert swap_state mods 2008-02-07 08:42:20 -08:00
swapfile.c d_path: Make seq_path() use a struct path argument 2008-02-14 21:17:08 -08:00
thrash.c Bug in mm/thrash.c function grab_swap_token() 2007-05-11 08:29:32 -07:00
tiny-shmem.c Remove unused code from mm/tiny-shmem.c 2008-02-05 09:44:17 -08:00
truncate.c page migraton: handle orphaned pages 2008-02-05 09:44:19 -08:00
util.c fix mm/util.c:krealloc() 2007-11-14 18:45:41 -08:00
vmalloc.c CONFIG_HIGHPTE vs. sub-page page tables. 2008-02-08 09:22:42 -08:00
vmscan.c per-zone and reclaim enhancements for memory controller: modifies vmscan.c for isolate globa/cgroup lru activity 2008-02-07 08:42:22 -08:00
vmstat.c vmstat: remove prefetch 2008-02-05 09:44:18 -08:00