On 12/26/2016 09:08 PM, Grygorii Maistrenko wrote:
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.
Signed-off-by: Grygorii Maistrenko <grygoriimkd@xxxxxxxxx>
Reviewed-by: Pekka Enberg <penberg@xxxxxxxxxx>
---
mm/slab_common.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
New in v2:
- (flags & SLAB_NEVER_MERGE) check is moved down below the flags update
as suggested by Christoph Lameter
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 329b03843863..a85a01439490 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))
continue;
--
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