memcg, slab: unregister cache from memcg before starting to destroy it

[deliverable/linux.git] / mm / memcontrol.c

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 451523c3bd4eb60c15bc5c8c4e4efac8fcd2c5d2..c22d8bf42d9a4923b175a9200f14aa9a62652e5d 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3140,6 +3140,7 @@ int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
                s->memcg_params->root_cache = root_cache;
                INIT_WORK(&s->memcg_params->destroy,
                                kmem_cache_destroy_work_func);
+               css_get(&memcg->css);
        } else
                s->memcg_params->is_root_cache = true;
 
@@ -3148,6 +3149,10 @@ int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
 
 void memcg_free_cache_params(struct kmem_cache *s)
 {
+       if (!s->memcg_params)
+               return;
+       if (!s->memcg_params->is_root_cache)
+               css_put(&s->memcg_params->memcg->css);
        kfree(s->memcg_params);
 }
 
@@ -3170,9 +3175,6 @@ void memcg_register_cache(struct kmem_cache *s)
        memcg = s->memcg_params->memcg;
        id = memcg_cache_id(memcg);
 
-       css_get(&memcg->css);
-
-
        /*
         * Since readers won't lock (see cache_from_memcg_idx()), we need a
         * barrier here to ensure nobody will see the kmem_cache partially
@@ -3221,10 +3223,8 @@ 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]);
+       VM_BUG_ON(root->memcg_params->memcg_caches[id] != s);
        root->memcg_params->memcg_caches[id] = NULL;
-
-       css_put(&memcg->css);
 }
 
 /*