Re: [PATCH v2 01/28] mm: memcontrol: remove dead code of checking parent memory cgroup

[Shakeel Butt]

On Wed, Dec 17, 2025 at 03:27:25PM +0800, Qi Zheng wrote:
> From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> 
> Since the no-hierarchy mode has been deprecated after the commit:
> 
>   commit bef8620cd8e0 ("mm: memcg: deprecate the non-hierarchical mode").
> 
> As a result, parent_mem_cgroup() will not return NULL except when passing
> the root memcg, and the root memcg cannot be offline. Hence, it's safe to
> remove the check on the returned value of parent_mem_cgroup(). Remove the
> corresponding dead code.
> 
> Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> Acked-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
> Reviewed-by: Harry Yoo <harry.yoo@xxxxxxxxxx>
> Reviewed-by: Chen Ridong <chenridong@xxxxxxxxxx>

Acked-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>