@@ -866,8 +866,7 @@ static inline struct mem_cgroup *lruvec_memcg(struct lruvec *lruvec)
* parent_mem_cgroup - find the accounting parent of a memcg
* @memcg: memcg whose parent to find
*
- * Returns the parent memcg, or NULL if this is the root or the memory
- * controller is in legacy no-hierarchy mode.
+ * Returns the parent memcg, or NULL if this is the root.
*/
static inline struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
{
@@ -3684,17 +3684,7 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg)
return;
parent = parent_mem_cgroup(memcg);
- if (!parent)
- parent = root_mem_cgroup;
-
memcg_reparent_objcgs(memcg, parent);
-
- /*
- * After we have finished memcg_reparent_objcgs(), all list_lrus
- * corresponding to this cgroup are guaranteed to remain empty.
- * The ordering is imposed by list_lru_node->lock taken by
- * memcg_reparent_list_lrus().
- */
memcg_reparent_list_lrus(memcg, parent);
}
#else
@@ -7195,8 +7185,6 @@ static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
break;
}
memcg = parent_mem_cgroup(memcg);
- if (!memcg)
- memcg = root_mem_cgroup;
}
return memcg;
}
@@ -409,13 +409,9 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg)
{
int i, nid;
long nr;
- struct mem_cgroup *parent;
+ struct mem_cgroup *parent = parent_mem_cgroup(memcg);
struct shrinker_info *child_info, *parent_info;
- parent = parent_mem_cgroup(memcg);
- if (!parent)
- parent = root_mem_cgroup;
-
/* Prevent from concurrent shrinker_info expand */
down_read(&shrinker_rwsem);
for_each_node(nid) {