23 Mar, 2011
2 commits
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Add some statistics for debugging.
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg -
OOM path is missing the irq restore in the CONFIG_CMPXCHG_LOCAL case.
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg
21 Mar, 2011
2 commits
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Conflicts:
include/linux/slub_def.h -
The redo label needs #ifdeffery. Fixes the following problem introduced by
commit 8a5ec0ba42c4 ("Lockless (and preemptless) fastpaths for slub"):mm/slub.c: In function 'slab_free':
mm/slub.c:2124: warning: label 'redo' defined but not usedReported-by: Stephen Rothwell
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg
12 Mar, 2011
3 commits
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Conflicts:
mm/slub.c -
The size of struct rcu_head may be changed. When it becomes larger,
it will pollute the page array.We reserve some some bytes for struct rcu_head when a slab
is allocated in this situation.Changed from V1:
use VM_BUG_ON instead BUG_ONAcked-by: Christoph Lameter
Signed-off-by: Lai Jiangshan
Signed-off-by: Pekka Enberg -
There is no "struct" for slub's slab, it shares with struct page.
But struct page is very small, it is insufficient when we need
to add some metadata for slab.So we add a field "reserved" to struct kmem_cache, when a slab
is allocated, kmem_cache->reserved bytes are automatically reserved
at the end of the slab for slab's metadata.Changed from v1:
Export the reserved field via sysfsAcked-by: Christoph Lameter
Signed-off-by: Lai Jiangshan
Signed-off-by: Pekka Enberg
11 Mar, 2011
2 commits
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Use the this_cpu_cmpxchg_double functionality to implement a lockless
allocation algorithm on arches that support fast this_cpu_ops.Each of the per cpu pointers is paired with a transaction id that ensures
that updates of the per cpu information can only occur in sequence on
a certain cpu.A transaction id is a "long" integer that is comprised of an event number
and the cpu number. The event number is incremented for every change to the
per cpu state. This means that the cmpxchg instruction can verify for an
update that nothing interfered and that we are updating the percpu structure
for the processor where we picked up the information and that we are also
currently on that processor when we update the information.This results in a significant decrease of the overhead in the fastpaths. It
also makes it easy to adopt the fast path for realtime kernels since this
is lockless and does not require the use of the current per cpu area
over the critical section. It is only important that the per cpu area is
current at the beginning of the critical section and at the end.So there is no need even to disable preemption.
Test results show that the fastpath cycle count is reduced by up to ~ 40%
(alloc/free test goes from ~140 cycles down to ~80). The slowpath for kfree
adds a few cycles.Sadly this does nothing for the slowpath which is where the main issues with
performance in slub are but the best case performance rises significantly.
(For that see the more complex slub patches that require cmpxchg_double)Kmalloc: alloc/free test
Before:
10000 times kmalloc(8)/kfree -> 134 cycles
10000 times kmalloc(16)/kfree -> 152 cycles
10000 times kmalloc(32)/kfree -> 144 cycles
10000 times kmalloc(64)/kfree -> 142 cycles
10000 times kmalloc(128)/kfree -> 142 cycles
10000 times kmalloc(256)/kfree -> 132 cycles
10000 times kmalloc(512)/kfree -> 132 cycles
10000 times kmalloc(1024)/kfree -> 135 cycles
10000 times kmalloc(2048)/kfree -> 135 cycles
10000 times kmalloc(4096)/kfree -> 135 cycles
10000 times kmalloc(8192)/kfree -> 144 cycles
10000 times kmalloc(16384)/kfree -> 754 cyclesAfter:
10000 times kmalloc(8)/kfree -> 78 cycles
10000 times kmalloc(16)/kfree -> 78 cycles
10000 times kmalloc(32)/kfree -> 82 cycles
10000 times kmalloc(64)/kfree -> 88 cycles
10000 times kmalloc(128)/kfree -> 79 cycles
10000 times kmalloc(256)/kfree -> 79 cycles
10000 times kmalloc(512)/kfree -> 85 cycles
10000 times kmalloc(1024)/kfree -> 82 cycles
10000 times kmalloc(2048)/kfree -> 82 cycles
10000 times kmalloc(4096)/kfree -> 85 cycles
10000 times kmalloc(8192)/kfree -> 82 cycles
10000 times kmalloc(16384)/kfree -> 706 cyclesKmalloc: Repeatedly allocate then free test
Before:
10000 times kmalloc(8) -> 211 cycles kfree -> 113 cycles
10000 times kmalloc(16) -> 174 cycles kfree -> 115 cycles
10000 times kmalloc(32) -> 235 cycles kfree -> 129 cycles
10000 times kmalloc(64) -> 222 cycles kfree -> 120 cycles
10000 times kmalloc(128) -> 343 cycles kfree -> 139 cycles
10000 times kmalloc(256) -> 827 cycles kfree -> 147 cycles
10000 times kmalloc(512) -> 1048 cycles kfree -> 272 cycles
10000 times kmalloc(1024) -> 2043 cycles kfree -> 528 cycles
10000 times kmalloc(2048) -> 4002 cycles kfree -> 571 cycles
10000 times kmalloc(4096) -> 7740 cycles kfree -> 628 cycles
10000 times kmalloc(8192) -> 8062 cycles kfree -> 850 cycles
10000 times kmalloc(16384) -> 8895 cycles kfree -> 1249 cyclesAfter:
10000 times kmalloc(8) -> 190 cycles kfree -> 129 cycles
10000 times kmalloc(16) -> 76 cycles kfree -> 123 cycles
10000 times kmalloc(32) -> 126 cycles kfree -> 124 cycles
10000 times kmalloc(64) -> 181 cycles kfree -> 128 cycles
10000 times kmalloc(128) -> 310 cycles kfree -> 140 cycles
10000 times kmalloc(256) -> 809 cycles kfree -> 165 cycles
10000 times kmalloc(512) -> 1005 cycles kfree -> 269 cycles
10000 times kmalloc(1024) -> 1999 cycles kfree -> 527 cycles
10000 times kmalloc(2048) -> 3967 cycles kfree -> 570 cycles
10000 times kmalloc(4096) -> 7658 cycles kfree -> 637 cycles
10000 times kmalloc(8192) -> 8111 cycles kfree -> 859 cycles
10000 times kmalloc(16384) -> 8791 cycles kfree -> 1173 cyclesSigned-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg -
The following patch will make the fastpaths lockless and will no longer
require interrupts to be disabled. Calling the free hook with irq disabled
will no longer be possible.Move the slab_free_hook_irq() logic into slab_free_hook. Only disable
interrupts if the features are selected that require callbacks with
interrupts off and reenable after calls have been made.Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg
27 Feb, 2011
1 commit
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mm/slub.c: In function 'ksize':
mm/slub.c:2728: error: implicit declaration of function 'slab_ksize'slab_ksize() needs to go out of CONFIG_SLUB_DEBUG section.
Acked-by: Randy Dunlap
Acked-by: David Rientjes
Signed-off-by: Mariusz Kozlowski
Signed-off-by: Pekka Enberg
23 Feb, 2011
1 commit
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Recent use of ksize() in network stack (commit ca44ac38 : net: don't
reallocate skb->head unless the current one hasn't the needed extra size
or is shared) triggers kmemcheck warnings, because ksize() can return
more space than kmemcheck is aware of.Pekka Enberg noticed SLAB+kmemcheck is doing the right thing, while SLUB
+kmemcheck doesnt.Bugzilla reference #27212
Reported-by: Christian Casteyde
Suggested-by: Pekka Enberg
Signed-off-by: Eric Dumazet
Acked-by: David S. Miller
Acked-by: David Rientjes
Acked-by: Christoph Lameter
CC: Changli Gao
CC: Andrew Morton
Signed-off-by: Pekka Enberg
24 Jan, 2011
1 commit
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The last user was ext4 and Eric Sandeen removed the call in a recent patch. See
the following URL for the discussion:http://marc.info/?l=linux-ext4&m=129546975702198&w=2
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg
15 Jan, 2011
1 commit
14 Jan, 2011
1 commit
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Signed-off-by: Joe Perches
Acked-by: Pekka Enberg
Cc: Jiri Kosina
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 Jan, 2011
2 commits
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The purpose of the locking is to prevent removal and additions
of nodes when statistics are gathered for a slab cache. So we
need to avoid racing with memory hotplug functionality.It is enough to take the memory hotplug locks there instead
of the slub_lock.online_pages() currently does not acquire the memory_hotplug
lock. Another patch will be submitted by the memory hotplug
authors to take the memory hotplug lock and describe the
uses of the memory hotplug lock to protect against
adding and removal of nodes from non hotplug data structures.Cc: # 2.6.37
Reported-and-tested-by: Bart Van Assche
Acked-by: David Rientjes
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg -
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
slub: Fix a crash during slabinfo -v
tracing/slab: Move kmalloc tracepoint out of inline code
slub: Fix slub_lock down/up imbalance
slub: Fix build breakage in Documentation/vm
slub tracing: move trace calls out of always inlined functions to reduce kernel code size
slub: move slabinfo.c to tools/slub/slabinfo.c
07 Jan, 2011
1 commit
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This is a nasty and error prone API. It is no longer used, remove it.
Signed-off-by: Nick Piggin
04 Dec, 2010
2 commits
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Commit f7cb1933621bce66a77f690776a16fe3ebbc4d58 ("SLUB: Pass active
and inactive redzone flags instead of boolean to debug functions")
missed two instances of check_object(). This caused a lot of warnings
during 'slabinfo -v' finally leading to a crash:BUG ext4_xattr: Freepointer corrupt
...
BUG buffer_head: Freepointer corrupt
...
BUG ext4_alloc_context: Freepointer corrupt
...
...
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: [] file_sb_list_del+0x1c/0x35
PGD 79d78067 PUD 79e67067 PMD 0
Oops: 0002 [#1] SMP
last sysfs file: /sys/kernel/slab/:t-0000192/validateThis patch fixes the problem by converting the two missed instances.
Acked-by: Christoph Lameter
Signed-off-by: Tero Roponen
Signed-off-by: Pekka Enberg -
Commit f7cb1933621bce66a77f690776a16fe3ebbc4d58 ("SLUB: Pass active
and inactive redzone flags instead of boolean to debug functions")
missed two instances of check_object(). This caused a lot of warnings
during 'slabinfo -v' finally leading to a crash:BUG ext4_xattr: Freepointer corrupt
...
BUG buffer_head: Freepointer corrupt
...
BUG ext4_alloc_context: Freepointer corrupt
...
...
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: [] file_sb_list_del+0x1c/0x35
PGD 79d78067 PUD 79e67067 PMD 0
Oops: 0002 [#1] SMP
last sysfs file: /sys/kernel/slab/:t-0000192/validateThis patch fixes the problem by converting the two missed instances.
Acked-by: Christoph Lameter
Signed-off-by: Tero Roponen
Signed-off-by: Pekka Enberg
14 Nov, 2010
1 commit
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There are two places, that do not release the slub_lock.
Respective bugs were introduced by sysfs changes ab4d5ed5 (slub: Enable
sysfs support for !CONFIG_SLUB_DEBUG) and 2bce6485 ( slub: Allow removal
of slab caches during boot).Acked-by: Christoph Lameter
Signed-off-by: Pavel Emelyanov
Signed-off-by: Pekka Enberg
06 Nov, 2010
2 commits
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There are two places, that do not release the slub_lock.
Respective bugs were introduced by sysfs changes ab4d5ed5 (slub: Enable
sysfs support for !CONFIG_SLUB_DEBUG) and 2bce6485 ( slub: Allow removal
of slab caches during boot).Acked-by: Christoph Lameter
Signed-off-by: Pavel Emelyanov
Signed-off-by: Pekka Enberg -
Having the trace calls defined in the always inlined kmalloc functions
in include/linux/slub_def.h causes a lot of code duplication as the
trace functions get instantiated for each kamalloc call site. This can
simply be removed by pushing the trace calls down into the functions in
slub.c.On my x86_64 built this patch shrinks the code size of the kernel by
approx 36K and also shrinks the code size of many modules -- too many to
list here ;)size vmlinux (2.6.36) reports
text data bss dec hex filename
5410611 743172 828928 6982711 6a8c37 vmlinux
5373738 744244 828928 6946910 6a005e vmlinux + patchThe resulting kernel has had some testing & kmalloc trace still seems to
work.This patch
- moves trace_kmalloc out of the inlined kmalloc() and pushes it down
into kmem_cache_alloc_trace() so this it only get instantiated once.- rename kmem_cache_alloc_notrace() to kmem_cache_alloc_trace() to
indicate that now is does have tracing. (maybe this would better being
called something like kmalloc_kmem_cache ?)- adds a new function kmalloc_order() to handle allocation and tracing
of large allocations of page order.- removes tracing from the inlined kmalloc_large() replacing them with a
call to kmalloc_order();- move tracing out of inlined kmalloc_node() and pushing it down into
kmem_cache_alloc_node_trace- rename kmem_cache_alloc_node_notrace() to
kmem_cache_alloc_node_trace()- removes the include of trace/events/kmem.h from slub_def.h.
v2
- keep kmalloc_order_trace inline when !CONFIG_TRACESigned-off-by: Richard Kennedy
Signed-off-by: Pekka Enberg
07 Oct, 2010
1 commit
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This patch fixes the following build breakage when memory hotplug is enabled on
UMA configurations:/home/test/linux-2.6/mm/slub.c: In function 'kmem_cache_init':
/home/test/linux-2.6/mm/slub.c:3031:2: error: 'slab_memory_callback'
undeclared (first use in this function)
/home/test/linux-2.6/mm/slub.c:3031:2: note: each undeclared
identifier is reported only once for each function it appears in
make[2]: *** [mm/slub.o] Error 1
make[1]: *** [mm] Error 2
make: *** [sub-make] Error 2Reported-by: Zimny Lech
Acked-by: Christoph Lameter
Signed-off-by: Pekka Enberg
06 Oct, 2010
3 commits
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There is a lot of #ifdef/#endifs that can be avoided if functions would be in different
places. Move them around and reduce #ifdef.Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg -
Currently disabling CONFIG_SLUB_DEBUG also disabled SYSFS support meaning
that the slabs cannot be tuned without DEBUG.Make SYSFS support independent of CONFIG_SLUB_DEBUG
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg -
This patch optimizes slab_free() debug check to use "c->node != NUMA_NO_NODE"
instead of "c->node >= 0" because the former generates smaller code on x86-64:Before:
4736: 48 39 70 08 cmp %rsi,0x8(%rax)
473a: 75 26 jne 4762
473c: 44 8b 48 10 mov 0x10(%rax),%r9d
4740: 45 85 c9 test %r9d,%r9d
4743: 78 1d js 4762After:
4736: 48 39 70 08 cmp %rsi,0x8(%rax)
473a: 75 23 jne 475f
473c: 83 78 10 ff cmpl $0xffffffffffffffff,0x10(%rax)
4740: 74 1d je 475fThis patch also cleans up __slab_alloc() to use NUMA_NO_NODE instead of "-1"
for enabling debugging for a per-CPU cache.Acked-by: Christoph Lameter
Acked-by: David Rientjes
Signed-off-by: Pekka Enberg
02 Oct, 2010
14 commits
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Make kmalloc_cache_alloc_node_notrace(), kmalloc_large_node()
and __kmalloc_node_track_caller() to be compiled only when
CONFIG_NUMA is selected.Acked-by: David Rientjes
Signed-off-by: Namhyung Kim
Signed-off-by: Pekka Enberg -
The unfreeze_slab() releases page's PG_locked bit but was missing
proper annotation. The deactivate_slab() needs to be marked also
since it calls unfreeze_slab() without grabbing the lock.Acked-by: David Rientjes
Signed-off-by: Namhyung Kim
Signed-off-by: Pekka Enberg -
The bit-ops routines require its arg to be a pointer to unsigned long.
This leads sparse to complain about different signedness as follows:mm/slub.c:2425:49: warning: incorrect type in argument 2 (different signedness)
mm/slub.c:2425:49: expected unsigned long volatile *addr
mm/slub.c:2425:49: got long *mapAcked-by: Christoph Lameter
Acked-by: David Rientjes
Signed-off-by: Namhyung Kim
Signed-off-by: Pekka Enberg -
There are a couple of places where repeat the same statements when removing
a page from the partial list. Consolidate that into __remove_partial().Acked-by: David Rientjes
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg -
Pass the actual values used for inactive and active redzoning to the
functions that check the objects. Avoids a lot of the ? : things to
lookup the values in the functions.Acked-by: David Rientjes
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg -
Reduce the #ifdefs and simplify bootstrap by making SMP and NUMA as much alike
as possible. This means that there will be an additional indirection to get to
the kmem_cache_node field under SMP.Acked-by: David Rientjes
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg -
This reverts commit 5249d039500f05a5ab379286b1d23ab9b04d3f2c. It's not needed
after commit bbddff0545878a8649c091a9dd7c43ce91516734 ("percpu: use percpu
allocator on UP too"). -
As explained by Linus "I'm Proud to be an American" Torvalds:
Looking at the merging code, I actually think it's totally
buggy. If you have something like this:- load module A: create slab cache A
- load module B: create slab cache B that can merge with A
- unload module A
- "cat /proc/slabinfo": BOOM. Oops.
exactly because the name is not handled correctly, and you'll have
module B holding open a slab cache that has a name pointer that points
to module A that no longer exists.This patch fixes the problem by using kstrdup() to allocate dynamic memory for
->name of "struct kmem_cache" as suggested by Christoph Lameter.Acked-by: Christoph Lameter
Cc: David Rientjes
Reported-by: Linus Torvalds
Signed-off-by: Pekka EnbergConflicts:
mm/slub.c
-
Since the percpu allocator does not provide early allocation in UP mode (only
in SMP configurations) use __get_free_page() to improvise a compound page
allocation that can be later freed via kfree().Compound pages will be released when the cpu caches are resized.
Acked-by: David Rientjes
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg -
Now that the kmalloc_caches array is dynamically allocated at boot,
SLUB_RESILIENCY_TEST needs to be fixed to pass the correct type.Acked-by: Christoph Lameter
Signed-off-by: David Rientjes
Signed-off-by: Pekka Enberg -
Memory hotplug allocates and frees per node structures. Use the correct name.
Acked-by: David Rientjes
Acked-by: Randy Dunlap
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg -
On Wed, 25 Aug 2010, Randy Dunlap wrote:
> mm/slub.c:1732: error: implicit declaration of function 'slab_pre_alloc_hook'
> mm/slub.c:1751: error: implicit declaration of function 'slab_post_alloc_hook'
> mm/slub.c:1881: error: implicit declaration of function 'slab_free_hook'
> mm/slub.c:1886: error: implicit declaration of function 'slab_free_hook_irq'Empty functions are missing if the runtime debuggability option is compiled
out.Provide the fall back functions to empty hooks if SLUB_DEBUG is not set.
Acked-by: Randy Dunlap
Acked-by: David Rientjes
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg -
Move the gfpflags masking into the hooks for checkers and into the slowpaths.
gfpflag masking requires access to a global variable and thus adds an
additional cacheline reference to the hotpaths.If no hooks are active then the gfpflag masking will result in
code that the compiler can toss out.Acked-by: David Rientjes
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg -
Extract the code that memory checkers and other verification tools use from
the hotpaths. Makes it easier to add new ones and reduces the disturbances
of the hotpaths.Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg
