diff options
| -rw-r--r-- | mm/memcontrol.c | 24 | ||||
| -rw-r--r-- | mm/slab.h | 12 |
2 files changed, 21 insertions, 15 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 739383cd3f70..322d18dc17f0 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3274,12 +3274,14 @@ void memcg_register_cache(struct kmem_cache *s) list_add(&s->memcg_params->list, &memcg->memcg_slab_caches); mutex_unlock(&memcg->slab_caches_mutex); - root->memcg_params->memcg_caches[id] = s; /* - * the readers won't lock, make sure everybody sees the updated value, - * so they won't put stuff in the queue again for no reason + * Since readers won't lock (see cache_from_memcg_idx()), we need a + * barrier here to ensure nobody will see the kmem_cache partially + * initialized. */ - wmb(); + smp_wmb(); + + root->memcg_params->memcg_caches[id] = s; } void memcg_unregister_cache(struct kmem_cache *s) @@ -3605,7 +3607,7 @@ struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp) { struct mem_cgroup *memcg; - int idx; + struct kmem_cache *memcg_cachep; VM_BUG_ON(!cachep->memcg_params); VM_BUG_ON(!cachep->memcg_params->is_root_cache); @@ -3619,15 +3621,9 @@ struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, if (!memcg_can_account_kmem(memcg)) goto out; - idx = memcg_cache_id(memcg); - - /* - * barrier to mare sure we're always seeing the up to date value. The - * code updating memcg_caches will issue a write barrier to match this. - */ - read_barrier_depends(); - if (likely(cache_from_memcg_idx(cachep, idx))) { - cachep = cache_from_memcg_idx(cachep, idx); + memcg_cachep = cache_from_memcg_idx(cachep, memcg_cache_id(memcg)); + if (likely(memcg_cachep)) { + cachep = memcg_cachep; goto out; } diff --git a/mm/slab.h b/mm/slab.h index 0859c4241ba1..72d1f9df71bd 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -163,9 +163,19 @@ static inline const char *cache_name(struct kmem_cache *s) static inline struct kmem_cache * cache_from_memcg_idx(struct kmem_cache *s, int idx) { + struct kmem_cache *cachep; + if (!s->memcg_params) return NULL; - return s->memcg_params->memcg_caches[idx]; + cachep = s->memcg_params->memcg_caches[idx]; + + /* + * Make sure we will access the up-to-date value. The code updating + * memcg_caches issues a write barrier to match this (see + * memcg_register_cache()). + */ + smp_read_barrier_depends(); + return cachep; } static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s) |