Re: [PATCH v2] mm: memcg: Don't periodically flush stats when memcg is disabled

[Yosry Ahmed]

On Fri, Jan 26, 2024 at 1:19 PM T.J. Mercier <tjmercier@xxxxxxxxxx> wrote:
>
> The root memcg is onlined even when memcg is disabled. When it's onlined
> a 2 second periodic stat flush is started, but no stat flushing is
> required when memcg is disabled because there can be no child memcgs.
> Most calls to flush memcg stats are avoided when memcg is disabled as a
> result of the mem_cgroup_disabled check added in 7d7ef0a4686a
> ("mm: memcg: restore subtree stats flushing"), but the periodic flushing
> started in mem_cgroup_css_online is not. Skip it.
>
> Fixes: aa48e47e3906 ("memcg: infrastructure to flush memcg stats")
> Reported-by: Minchan Kim <minchan@xxxxxxxxxx>
> Signed-off-by: T.J. Mercier <tjmercier@xxxxxxxxxx>
> Acked-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>

Reviewed-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>

Thanks!