Commit 90c7a79c authored by Andrey Vagin's avatar Andrey Vagin Committed by Linus Torvalds

kmemcg: don't allocate extra memory for root memcg_cache_params

The memcg_cache_params structure contains the common part and the union,
which represents two different types of data: one for root cashes and
another for child caches.

The size of child data is fixed.  The size of the memcg_caches array is
calculated in runtime.

Currently the size of memcg_cache_params for root caches is calculated
incorrectly, because it includes the size of parameters for child caches.

ssize_t size = memcg_caches_array_size(num_groups);
size *= sizeof(void *);

size += sizeof(struct memcg_cache_params);

v2: Fix a typo in calculations
Signed-off-by: default avatarAndrey Vagin <avagin@openvz.org>
Cc: Glauber Costa <glommer@openvz.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e76b63f8
...@@ -3121,7 +3121,7 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups) ...@@ -3121,7 +3121,7 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
ssize_t size = memcg_caches_array_size(num_groups); ssize_t size = memcg_caches_array_size(num_groups);
size *= sizeof(void *); size *= sizeof(void *);
size += sizeof(struct memcg_cache_params); size += offsetof(struct memcg_cache_params, memcg_caches);
s->memcg_params = kzalloc(size, GFP_KERNEL); s->memcg_params = kzalloc(size, GFP_KERNEL);
if (!s->memcg_params) { if (!s->memcg_params) {
...@@ -3164,13 +3164,16 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups) ...@@ -3164,13 +3164,16 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s, int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
struct kmem_cache *root_cache) struct kmem_cache *root_cache)
{ {
size_t size = sizeof(struct memcg_cache_params); size_t size;
if (!memcg_kmem_enabled()) if (!memcg_kmem_enabled())
return 0; return 0;
if (!memcg) if (!memcg) {
size = offsetof(struct memcg_cache_params, memcg_caches);
size += memcg_limited_groups_array_size * sizeof(void *); size += memcg_limited_groups_array_size * sizeof(void *);
} else
size = sizeof(struct memcg_cache_params);
s->memcg_params = kzalloc(size, GFP_KERNEL); s->memcg_params = kzalloc(size, GFP_KERNEL);
if (!s->memcg_params) if (!s->memcg_params)
......
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