diff options
| -rw-r--r-- | mm/memcontrol.c | 23 | ||||
| -rw-r--r-- | mm/slab_common.c | 14 |
2 files changed, 27 insertions, 10 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 014a4f1acf1c..d2da65c4cd84 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3264,6 +3264,12 @@ void memcg_register_cache(struct kmem_cache *s) if (is_root_cache(s)) return; + /* + * Holding the slab_mutex assures nobody will touch the memcg_caches + * array while we are modifying it. + */ + lockdep_assert_held(&slab_mutex); + root = s->memcg_params->root_cache; memcg = s->memcg_params->memcg; id = memcg_cache_id(memcg); @@ -3283,6 +3289,7 @@ void memcg_register_cache(struct kmem_cache *s) * before adding it to the memcg_slab_caches list, otherwise we can * fail to convert memcg_params_to_cache() while traversing the list. */ + VM_BUG_ON(root->memcg_params->memcg_caches[id]); root->memcg_params->memcg_caches[id] = s; mutex_lock(&memcg->slab_caches_mutex); @@ -3299,6 +3306,12 @@ void memcg_unregister_cache(struct kmem_cache *s) if (is_root_cache(s)) return; + /* + * Holding the slab_mutex assures nobody will touch the memcg_caches + * array while we are modifying it. + */ + lockdep_assert_held(&slab_mutex); + root = s->memcg_params->root_cache; memcg = s->memcg_params->memcg; id = memcg_cache_id(memcg); @@ -3312,6 +3325,7 @@ void memcg_unregister_cache(struct kmem_cache *s) * after removing it from the memcg_slab_caches list, otherwise we can * fail to convert memcg_params_to_cache() while traversing the list. */ + VM_BUG_ON(!root->memcg_params->memcg_caches[id]); root->memcg_params->memcg_caches[id] = NULL; css_put(&memcg->css); @@ -3464,22 +3478,13 @@ static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg, struct kmem_cache *cachep) { struct kmem_cache *new_cachep; - int idx; BUG_ON(!memcg_can_account_kmem(memcg)); - idx = memcg_cache_id(memcg); - mutex_lock(&memcg_cache_mutex); - new_cachep = cache_from_memcg_idx(cachep, idx); - if (new_cachep) - goto out; - new_cachep = kmem_cache_dup(memcg, cachep); if (new_cachep == NULL) new_cachep = cachep; - -out: mutex_unlock(&memcg_cache_mutex); return new_cachep; } diff --git a/mm/slab_common.c b/mm/slab_common.c index db24ec48b946..f34707eeacc7 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -180,6 +180,18 @@ kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size, if (err) goto out_unlock; + if (memcg) { + /* + * Since per-memcg caches are created asynchronously on first + * allocation (see memcg_kmem_get_cache()), several threads can + * try to create the same cache, but only one of them may + * succeed. Therefore if we get here and see the cache has + * already been created, we silently return NULL. + */ + if (cache_from_memcg_idx(parent_cache, memcg_cache_id(memcg))) + goto out_unlock; + } + /* * Some allocators will constraint the set of valid flags to a subset * of all flags. We expect them to define CACHE_CREATE_MASK in this @@ -261,11 +273,11 @@ void kmem_cache_destroy(struct kmem_cache *s) list_del(&s->list); if (!__kmem_cache_shutdown(s)) { + memcg_unregister_cache(s); mutex_unlock(&slab_mutex); if (s->flags & SLAB_DESTROY_BY_RCU) rcu_barrier(); - memcg_unregister_cache(s); memcg_free_cache_params(s); kfree(s->name); kmem_cache_free(kmem_cache, s); |