Subject: + bug-using-__this_cpu_add-in-preemptible-code-init-1.patch added to -mm tree
To: cl@xxxxxxxxx,fengguang.wu@xxxxxxxxx,penberg@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 19 Mar 2014 15:33:15 -0700
The patch titled
Subject: slub: use raw_cpu_inc for incrementing statistics
has been added to the -mm tree. Its filename is
bug-using-__this_cpu_add-in-preemptible-code-init-1.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/bug-using-__this_cpu_add-in-preemptible-code-init-1.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/bug-using-__this_cpu_add-in-preemptible-code-init-1.patch
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------------------------------------------------------
From: Christoph Lameter <cl@xxxxxxxxx>
Subject: slub: use raw_cpu_inc for incrementing statistics
Statistics are not critical to the operation of the allocation
but should also not cause too much overhead.
When __this_cpu_inc is altered to check if preemption is disabled this
triggers. Use raw_cpu_inc to avoid the checks. Using this_cpu_ops may
cause interrupt disable/enable sequences on various arches which may
significantly impact allocator performance.
Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
Cc: Fengguang Wu <fengguang.wu@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slub.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/slub.c~bug-using-__this_cpu_add-in-preemptible-code-init-1 mm/slub.c
--- a/mm/slub.c~bug-using-__this_cpu_add-in-preemptible-code-init-1
+++ a/mm/slub.c
@@ -224,7 +224,7 @@ static inline void memcg_propagate_slab_
static inline void stat(const struct kmem_cache *s, enum stat_item si)
{
#ifdef CONFIG_SLUB_STATS
- __this_cpu_inc(s->cpu_slab->stat[si]);
+ raw_cpu_inc(s->cpu_slab->stat[si]);
#endif
}
_
Patches currently in -mm which might be from cl@xxxxxxxxx are
slub-fix-high-order-page-allocation-problem-with-__gfp_nofail.patch
kthread-ensure-locality-of-task_struct-allocations.patch
mm-slab-slub-use-page-list-consistently-instead-of-page-lru.patch
kobject-dont-block-for-each-kobject_uevent.patch
kobject-dont-block-for-each-kobject_uevent-v2.patch
slub-do-not-drop-slab_mutex-for-sysfs_slab_add.patch
fork-collapse-copy_flags-into-copy_process.patch
mm-mempolicy-rename-slab_node-for-clarity.patch
mm-mempolicy-remove-per-process-flag.patch
res_counter-remove-interface-for-locked-charging-and-uncharging.patch
kmod-run-usermodehelpers-only-on-cpus-allowed-for-kthreadd-v2.patch
kmod-run-usermodehelpers-only-on-cpus-allowed-for-kthreadd-v2-fix.patch
kmod-run-usermodehelpers-only-on-cpus-allowed-for-kthreadd-v2-checkpatch-fixes.patch
linux-next.patch
percpu-add-raw_cpu_ops.patch
mm-use-raw_cpu-ops-for-determining-current-numa-node.patch
modules-use-raw_cpu_write-for-initialization-of-per-cpu-refcount.patch
net-replace-__this_cpu_inc-in-routec-with-raw_cpu_inc.patch
bug-using-__this_cpu_add-in-preemptible-code-init-1.patch
percpu-add-preemption-checks-to-__this_cpu-ops.patch
percpu-add-preemption-checks-to-__this_cpu-ops-fix.patch
percpu-add-preemption-checks-to-__this_cpu-ops-fix-checkpatch-fixes.patch
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