Re: [PATCH 3/4] mm/memcg: retrieve parent memcg from css.parent

From: Michal Hocko
Date: Tue Jan 11 2022 - 03:43:12 EST


On Tue 11-01-22 01:03:01, Wei Yang wrote:
> 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.
>
> Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>

Acked-by: Michal Hocko <mhocko@xxxxxxxx>

> ---
> include/linux/memcontrol.h | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 0c5c403f4be6..12bf443f7b14 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -886,9 +886,7 @@ static inline struct mem_cgroup *lruvec_memcg(struct lruvec *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,
> --
> 2.33.1

--
Michal Hocko
SUSE Labs