diff options
| author | Shakeel Butt <shakeelb@google.com> | 2018-04-05 16:21:50 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-05 21:36:24 -0700 |
| commit | 613a5eb5677923fdaecfa582738c7bcf80abe186 (patch) | |
| tree | e5fd12d7868c38128beeddd77a9dfc5d95be22e8 /mm | |
| parent | 302d55d51d04ab92f8b3f6a89d3424299e3efdf7 (diff) | |
slab, slub: remove size disparity on debug kernel
I have noticed on debug kernel with SLAB, the size of some non-root
slabs were larger than their corresponding root slabs.
e.g. for radix_tree_node:
$cat /proc/slabinfo | grep radix
name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab> ...
radix_tree_node 15052 15075 4096 1 1 ...
$cat /cgroup/memory/temp/memory.kmem.slabinfo | grep radix
name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab> ...
radix_tree_node 1581 158 4120 1 2 ...
However for SLUB in debug kernel, the sizes were same. On further
inspection it is found that SLUB always use kmem_cache.object_size to
measure the kmem_cache.size while SLAB use the given kmem_cache.size.
In the debug kernel the slab's size can be larger than its object_size.
Thus in the creation of non-root slab, the SLAB uses the root's size as
base to calculate the non-root slab's size and thus non-root slab's size
can be larger than the root slab's size. For SLUB, the non-root slab's
size is measured based on the root's object_size and thus the size will
remain same for root and non-root slab.
This patch makes slab's object_size the default base to measure the
slab's size.
Link: http://lkml.kernel.org/r/20180313165428.58699-1-shakeelb@google.com
Fixes: 794b1248be4e ("memcg, slab: separate memcg vs root cache creation paths")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/slab_common.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c index e2e2485b3496..4a4bd71ab728 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -379,7 +379,7 @@ struct kmem_cache *find_mergeable(unsigned int size, unsigned int align, } static struct kmem_cache *create_cache(const char *name, - unsigned int object_size, unsigned int size, unsigned int align, + unsigned int object_size, unsigned int align, slab_flags_t flags, unsigned int useroffset, unsigned int usersize, void (*ctor)(void *), struct mem_cgroup *memcg, struct kmem_cache *root_cache) @@ -396,8 +396,7 @@ static struct kmem_cache *create_cache(const char *name, goto out; s->name = name; - s->object_size = object_size; - s->size = size; + s->size = s->object_size = object_size; s->align = align; s->ctor = ctor; s->useroffset = useroffset; @@ -503,7 +502,7 @@ kmem_cache_create_usercopy(const char *name, goto out_unlock; } - s = create_cache(cache_name, size, size, + s = create_cache(cache_name, size, calculate_alignment(flags, align, size), flags, useroffset, usersize, ctor, NULL, NULL); if (IS_ERR(s)) { @@ -650,7 +649,7 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg, goto out_unlock; s = create_cache(cache_name, root_cache->object_size, - root_cache->size, root_cache->align, + root_cache->align, root_cache->flags & CACHE_CREATE_MASK, root_cache->useroffset, root_cache->usersize, root_cache->ctor, memcg, root_cache); |