mem_cgroup_is_descendant
match = mem_cgroup_is_descendant(task_memcg, memcg);
if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) &&
!mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg))
if (unlikely(!mem_cgroup_is_descendant(memcg, oom_domain)))
mem_cgroup_is_descendant(memcg, root_memcg)) {
if (memcg && mem_cgroup_is_descendant(memcg, root_memcg)) {