memcg: convert to use cgroup_is_descendant()
This is a preparation to kill css_id.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d5ff3ce..aa8363e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1318,7 +1318,7 @@
return true;
if (!root_memcg->use_hierarchy || !memcg)
return false;
- return css_is_ancestor(&memcg->css, &root_memcg->css);
+ return cgroup_is_descendant(memcg->css.cgroup, root_memcg->css.cgroup);
}
static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,