From 90c7a79cc45becc6cdb8c026d55ace19e299a02d Mon Sep 17 00:00:00 2001 From: Andrey Vagin Date: Wed, 11 Sep 2013 14:22:18 -0700 Subject: [PATCH] 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: Andrey Vagin Cc: Glauber Costa Cc: Johannes Weiner Cc: Michal Hocko Cc: Balbir Singh Cc: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 3b83957..5ca1dcf 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -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); 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) { @@ -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, 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) -- 2.7.4