Re: [RFC PATCH 6/7] workingset: memcg: sleep when flushing stats in workingset_refault()

Yosry Ahmed
2023-03-23T16:02:51Z

On Thu, Mar 23, 2023 at 8:50 AM Johannes Weiner <hannes@cmpxchg.org> wrote:
>
> On Thu, Mar 23, 2023 at 04:00:36AM +0000, Yosry Ahmed wrote:
> > In workingset_refault(), we call mem_cgroup_flush_stats_delayed() to
> > flush stats within an RCU read section and with sleeping disallowed.
> > Move the call to mem_cgroup_flush_stats_delayed() above the RCU read
> > section and allow sleeping to avoid unnecessarily performing a lot of
> > work without sleeping.
> >
> > Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
> > ---
> >
> > A lot of code paths call into workingset_refault(), so I am not
> > generally sure at all whether it's okay to sleep in all contexts or not.
> > Feedback here would be very helpful.
>
> Yes, it's safe.

Thanks! That's very helpful!