diff options
authorGrygorii Maistrenko <grygoriimkd@gmail.com>2017-02-22 15:40:59 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-22 16:41:27 -0800
commitc6e28895a4372992961888ffaadc9efc643b5bfe (patch)
parent8dcde9def5a15df54fa4ca41f7750d80fa741d61 (diff)
slub: do not merge cache if slub_debug contains a never-merge flag
In case CONFIG_SLUB_DEBUG_ON=n, find_mergeable() gets debug features from commandline but never checks if there are features from the SLAB_NEVER_MERGE set. As a result selected by slub_debug caches are always mergeable if they have been created without a custom constructor set or without one of the SLAB_* debug features on. This moves the SLAB_NEVER_MERGE check below the flags update from commandline to make sure it won't merge the slab cache if one of the debug features is on. Link: http://lkml.kernel.org/r/20170101124451.GA4740@lp-laptop-d Signed-off-by: Grygorii Maistrenko <grygoriimkd@gmail.com> Reviewed-by: Pekka Enberg <penberg@kernel.org> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 files changed, 4 insertions, 1 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c
index ae323841adb1..36a263e9c81a 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -255,7 +255,7 @@ struct kmem_cache *find_mergeable(size_t size, size_t align,
struct kmem_cache *s;
- if (slab_nomerge || (flags & SLAB_NEVER_MERGE))
+ if (slab_nomerge)
return NULL;
if (ctor)
@@ -266,6 +266,9 @@ struct kmem_cache *find_mergeable(size_t size, size_t align,
size = ALIGN(size, align);
flags = kmem_cache_flags(size, flags, name, NULL);
+ if (flags & SLAB_NEVER_MERGE)
+ return NULL;
list_for_each_entry_reverse(s, &slab_caches, list) {
if (slab_unmergeable(s))

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