The patch titled
Subject: mm/slab: fix kmemcg cache creation delayed issue
has been added to the -mm tree. Its filename is
mm-slab-fix-kmemcg-cache-creation-delayed-issue.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-slab-fix-kmemcg-cache-creation-delayed-issue.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-slab-fix-kmemcg-cache-creation-delayed-issue.patch
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From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Subject: mm/slab: fix kmemcg cache creation delayed issue
There is a bug report that SLAB makes extreme load average due to over
2000 kworker thread.
https://bugzilla.kernel.org/show_bug.cgi?id=172981
This issue is caused by kmemcg feature that try to create new set of
kmem_caches for each memcg. Recently, kmem_cache creation is slowed by
synchronize_sched() and futher kmem_cache creation is also delayed since
kmem_cache creation is synchronized by a global slab_mutex lock. So, the
number of kworker that try to create kmem_cache increases quitely.
synchronize_sched() is for lockless access to node's shared array but it's
not needed when a new kmem_cache is created. So, this patch rules out
that case.
Fixes: 801faf0db894 ("mm/slab: lockless decision to grow cache")
Link: http://lkml.kernel.org/r/1475734855-4837-1-git-send-email-iamjoonsoo.kim@xxxxxxx
Reported-by: Doug Smythies <dsmythies@xxxxxxxxx>
Tested-by: Doug Smythies <dsmythies@xxxxxxxxx>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/slab.c~mm-slab-fix-kmemcg-cache-creation-delayed-issue mm/slab.c
--- a/mm/slab.c~mm-slab-fix-kmemcg-cache-creation-delayed-issue
+++ a/mm/slab.c
@@ -966,7 +966,7 @@ static int setup_kmem_cache_node(struct
* guaranteed to be valid until irq is re-enabled, because it will be
* freed after synchronize_sched().
*/
- if (force_change)
+ if (old_shared && force_change)
synchronize_sched();
fail:
_
Patches currently in -mm which might be from iamjoonsoo.kim@xxxxxxx are
mm-slab-fix-kmemcg-cache-creation-delayed-issue.patch
mm-debug_pagealloc-clean-up-guard-page-handling-code.patch
mm-debug_pagealloc-dont-allocate-page_ext-if-we-dont-use-guard-page.patch
mm-page_owner-move-page_owner-specific-function-to-page_ownerc.patch
mm-page_ext-rename-offset-to-index.patch
mm-page_ext-support-extra-space-allocation-by-page_ext-user.patch
mm-page_owner-dont-define-fields-on-struct-page_ext-by-hard-coding.patch
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