1 files changed, 46 insertions, 63 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ef00c57fe6bb..b4b6aef562fa 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3094,6 +3094,29 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
 	return 0;
 }
 
+char *memcg_create_cache_name(struct mem_cgroup *memcg,
+			      struct kmem_cache *root_cache)
+{
+	static char *buf = NULL;
+
+	/*
+	 * We need a mutex here to protect the shared buffer. Since this is
+	 * expected to be called only on cache creation, we can employ the
+	 * slab_mutex for that purpose.
+	 */
+	lockdep_assert_held(&slab_mutex);
+
+	if (!buf) {
+		buf = kmalloc(NAME_MAX + 1, GFP_KERNEL);
+		if (!buf)
+			return NULL;
+	}
+
+	cgroup_name(memcg->css.cgroup, buf, NAME_MAX + 1);
+	return kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name,
+			 memcg_cache_id(memcg), buf);
+}
+
 int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
 			     struct kmem_cache *root_cache)
 {
@@ -3117,6 +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;
 
@@ -3125,6 +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);
 }
 
@@ -3147,9 +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
@@ -3198,10 +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);
 }
 
 /*
@@ -3298,55 +3321,10 @@ void mem_cgroup_destroy_cache(struct kmem_cache *cachep)
 	schedule_work(&cachep->memcg_params->destroy);
 }
 
-static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
-						  struct kmem_cache *s)
-{
-	struct kmem_cache *new = NULL;
-	static char *tmp_path = NULL, *tmp_name = NULL;
-	static DEFINE_MUTEX(mutex);	/* protects tmp_name */
-
-	BUG_ON(!memcg_can_account_kmem(memcg));
-
-	mutex_lock(&mutex);
-	/*
-	 * kmem_cache_create_memcg duplicates the given name and
-	 * cgroup_name for this name requires RCU context.
-	 * This static temporary buffer is used to prevent from
-	 * pointless shortliving allocation.
-	 */
-	if (!tmp_path || !tmp_name) {
-		if (!tmp_path)
-			tmp_path = kmalloc(PATH_MAX, GFP_KERNEL);
-		if (!tmp_name)
-			tmp_name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
-		if (!tmp_path || !tmp_name)
-			goto out;
-	}
-
-	cgroup_name(memcg->css.cgroup, tmp_name, NAME_MAX + 1);
-	snprintf(tmp_path, PATH_MAX, "%s(%d:%s)", s->name,
-		 memcg_cache_id(memcg), tmp_name);
-
-	new = kmem_cache_create_memcg(memcg, tmp_path, s->object_size, s->align,
-				      (s->flags & ~SLAB_PANIC), s->ctor, s);
-	if (new)
-		new->allocflags |= __GFP_KMEMCG;
-	else
-		new = s;
-out:
-	mutex_unlock(&mutex);
-	return new;
-}
-
-void kmem_cache_destroy_memcg_children(struct kmem_cache *s)
+int __kmem_cache_destroy_memcg_children(struct kmem_cache *s)
 {
 	struct kmem_cache *c;
-	int i;
-
-	if (!s->memcg_params)
-		return;
-	if (!s->memcg_params->is_root_cache)
-		return;
+	int i, failed = 0;
 
 	/*
 	 * If the cache is being destroyed, we trust that there is no one else
@@ -3380,16 +3358,14 @@ void kmem_cache_destroy_memcg_children(struct kmem_cache *s)
 		c->memcg_params->dead = false;
 		cancel_work_sync(&c->memcg_params->destroy);
 		kmem_cache_destroy(c);
+
+		if (cache_from_memcg_idx(s, i))
+			failed++;
 	}
 	mutex_unlock(&activate_kmem_mutex);
+	return failed;
 }
 
-struct create_work {
-	struct mem_cgroup *memcg;
-	struct kmem_cache *cachep;
-	struct work_struct work;
-};
-
 static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg)
 {
 	struct kmem_cache *cachep;
@@ -3407,13 +3383,20 @@ static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg)
 	mutex_unlock(&memcg->slab_caches_mutex);
 }
 
+struct create_work {
+	struct mem_cgroup *memcg;
+	struct kmem_cache *cachep;
+	struct work_struct work;
+};
+
 static void memcg_create_cache_work_func(struct work_struct *w)
 {
-	struct create_work *cw;
+	struct create_work *cw = container_of(w, struct create_work, work);
+	struct mem_cgroup *memcg = cw->memcg;
+	struct kmem_cache *cachep = cw->cachep;
 
-	cw = container_of(w, struct create_work, work);
-	memcg_create_kmem_cache(cw->memcg, cw->cachep);
-	css_put(&cw->memcg->css);
+	kmem_cache_create_memcg(memcg, cachep);
+	css_put(&memcg->css);
 	kfree(cw);
 }