Messages in this thread Patch in this message | | | From | Andrey Vagin <> | Subject | [PATCH] kmemcg: don't allocate extra memory for root memcg_cache_params (v2) | Date | Thu, 15 Aug 2013 09:49:00 +0400 |
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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
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> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrey Vagin <avagin@openvz.org> --- mm/memcontrol.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c5792a5..2e47fea 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3140,7 +3140,7 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups) ssize_t size = memcg_caches_array_size(num_groups); size *= sizeof(void *); - size += sizeof(struct memcg_cache_params); + size += offsetof(struct memcg_cache_params, memcg_caches); s->memcg_params = kzalloc(size, GFP_KERNEL); if (!s->memcg_params) { @@ -3183,13 +3183,16 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups) int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s, struct kmem_cache *root_cache) { - size_t size = sizeof(struct memcg_cache_params); + size_t size; if (!memcg_kmem_enabled()) return 0; - if (!memcg) + if (!memcg) { + size = offsetof(struct memcg_cache_params, memcg_caches); size += memcg_limited_groups_array_size * sizeof(void *); + } else + size = sizeof(struct memcg_cache_params); s->memcg_params = kzalloc(size, GFP_KERNEL); if (!s->memcg_params) -- 1.8.3.1
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