[PATCH v2 1/1] psi: stop relying on timer_pending for poll_work rescheduling

[Suren Baghdasaryan]

On Thu, Jul 1, 2021 at 1:59 AM Peter Zijlstra <peterz at infradead.org> wrote:
>
> On Wed, Jun 30, 2021 at 01:51:51PM -0700, Suren Baghdasaryan wrote:
> > +     /* cmpxchg should be called even when !force to set poll_scheduled */
> > +     if (atomic_cmpxchg(&group->poll_scheduled, 0, 1) && !force)
> >               return;
>
> Why is that a cmpxchg() ?

We want to set poll_scheduled and proceed with rescheduling the timer
unless it's already scheduled, so cmpxchg helps us to make that
decision atomically. Or did I misunderstand your question?

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