From: Wei Yang <richard.weiyang@xxxxxxxxx> Subject: mm/memcg: retrieve parent memcg from css.parent The parent we get from page_counter is correct, while this is two different hierarchy. Let's retrieve the parent memcg from css.parent just like parent_cs(), blkcg_parent(), etc. Link: https://lkml.kernel.org/r/20220201004643.8391-2-richard.weiyang@xxxxxxxxx Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Reviewed-by: Roman Gushchin <guro@xxxxxx> Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx> Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> Cc: Yang Shi <shy828301@xxxxxxxxx> Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/memcontrol.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/include/linux/memcontrol.h~mm-memcg-retrieve-parent-memcg-from-cssparent +++ a/include/linux/memcontrol.h @@ -842,9 +842,7 @@ static inline struct mem_cgroup *lruvec_ */ static inline struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg) { - if (!memcg->memory.parent) - return NULL; - return mem_cgroup_from_counter(memcg->memory.parent, memory); + return mem_cgroup_from_css(memcg->css.parent); } static inline bool mem_cgroup_is_descendant(struct mem_cgroup *memcg, _
