Re: [PATCH 2/2] mm, memcg: Decouple e{low,min} state mutations from protection checks

Johannes Weiner
2020-04-28T21:20:06Z

On Tue, Apr 28, 2020 at 07:27:00PM +0100, Chris Down wrote:
> mem_cgroup_protected currently is both used to set effective low and min
> and return a mem_cgroup_protection based on the result. As a user, this
> can be a little unexpected: it appears to be a simple predicate
> function, if not for the big warning in the comment above about the
> order in which it must be executed.
>
> This change makes it so that we separate the state mutations from the
> actual protection checks, which makes it more obvious where we need to
> be careful mutating internal state, and where we are simply checking and
> don't need to worry about that.
>
> Signed-off-by: Chris Down <chris@chrisdown.name>
> Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Roman Gushchin <guro@fb.com>
> Cc: Yafang Shao <laoar.shao@gmail.com>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>