Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1516616

[PATCH v3 1/2] memcg: Prevent memcg caches to be both OFF_SLAB & OBJFREELIST_SLAB

Show all headers | View raw

From: Greg Thelen <gthelen@google.com>

While testing OBJFREELIST_SLAB integration with pagealloc, we found a
bug where kmem_cache(sys) would be created with both CFLGS_OFF_SLAB &
CFLGS_OBJFREELIST_SLAB.

The original kmem_cache is created early making OFF_SLAB not possible.
When kmem_cache(sys) is created, OFF_SLAB is possible and if pagealloc
is enabled it will try to enable it first under certain conditions.
Given kmem_cache(sys) reuses the original flag, you can have both flags
at the same time resulting in allocation failures and odd behaviors.

This fix discards allocator specific flags from memcg before calling
create_cache.

Fixes: b03a017bebc4 ("mm/slab: introduce new slab management type, OBJFREELIST_SLAB")
Signed-off-by: Greg Thelen <gthelen@google.com>
Tested-by: Thomas Garnier <thgarnie@google.com>
---
Based on next-20161027
---
 mm/slab_common.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 71f0b28..329b038 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -533,8 +533,8 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg,
 
 	s = create_cache(cache_name, root_cache->object_size,
 			 root_cache->size, root_cache->align,
-			 root_cache->flags, root_cache->ctor,
-			 memcg, root_cache);
+			 root_cache->flags & CACHE_CREATE_MASK,
+			 root_cache->ctor, memcg, root_cache);
 	/*
 	 * If we could not create a memcg cache, do not complain, because
 	 * that's not critical at all as we can always proceed with the root
-- 
2.8.0.rc3.226.g39d4020

Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

[PATCH v3 1/2] memcg: Prevent memcg caches to be both OFF_SLAB & OBJFREELIST_SLAB Thomas Garnier <thgarnie@google.com> - 2016-11-07 22:50 +0100
  Re: [PATCH v3 1/2] memcg: Prevent memcg caches to be both OFF_SLAB  & OBJFREELIST_SLAB Andrew Morton <akpm@linux-foundation.org> - 2016-11-07 23:40 +0100
    Re: [PATCH v3 1/2] memcg: Prevent memcg caches to be both OFF_SLAB & OBJFREELIST_SLAB Thomas Garnier <thgarnie@google.com> - 2016-11-07 23:40 +0100
      Re: [PATCH v3 1/2] memcg: Prevent memcg caches to be both OFF_SLAB  & OBJFREELIST_SLAB Andrew Morton <akpm@linux-foundation.org> - 2016-11-07 23:50 +0100
        Re: [PATCH v3 1/2] memcg: Prevent memcg caches to be both OFF_SLAB & OBJFREELIST_SLAB Thomas Garnier <thgarnie@google.com> - 2016-11-08 05:30 +0100
        Re: [PATCH v3 1/2] memcg: Prevent memcg caches to be both OFF_SLAB  & OBJFREELIST_SLAB Christoph Lameter <cl@linux.com> - 2016-11-09 01:00 +0100

csiph-web