Re: [PATCH v2 3/3] mm/memcg: Unify swap and memsw page counters

[Shakeel Butt]

On Sun, Sep 13, 2020 at 7:45 PM Waiman Long <longman@xxxxxxxxxx> wrote:
>
> The swap page counter is v2 only while memsw is v1 only. As v1 and v2
> controllers cannot be active at the same time, there is no point to keep
> both swap and memsw page counters in mem_cgroup. The previous patch has
> made sure that memsw page counter is updated and accessed only when in
> v1 code paths. So it is now safe to alias the v1 memsw page counter to v2
> swap page counter. This saves 14 long's in the size of mem_cgroup. This
> is a saving of 112 bytes for 64-bit archs.
>
> While at it, also document which page counters are used in v1 and/or v2.
>
> Signed-off-by: Waiman Long <longman@xxxxxxxxxx>

Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>