Re: [RFC PATCH 02/15] mm: memcontrol: bail out early when !mm in get_mem_cgroup_from_mm

[Johannes Weiner]

On Tue, Mar 30, 2021 at 06:15:18PM +0800, Muchun Song wrote:
> When mm is NULL, we do not need to hold rcu lock and call css_tryget for
> the root memcg. And we also do not need to check !mm in every loop of
> while. So bail out early when !mm.
> 
> Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>

Good observation.

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>