-static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
-{
- while (!atomic_inc_not_zero(&memcg->id.ref)) {
- /*
- * The root cgroup cannot be destroyed, so it's refcount must
- * always be >= 1.
- */
- if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
- VM_BUG_ON(1);
- break;
- }
- memcg = parent_mem_cgroup(memcg);
- if (!memcg)
- memcg = root_mem_cgroup;
- }
- return memcg;
-}
-