Re: [PATCH 1/4] cpufreq: stats: Defer stats update to cpufreq_stats_record_transition()

Viresh Kumar
2020-09-11T11:36:53Z

On 11-09-20, 12:11, peterz@infradead.org wrote:
> On Wed, Sep 02, 2020 at 12:54:41PM +0530, Viresh Kumar wrote:
> > + atomic_t reset_pending;
>
> > + atomic_set(&stats->reset_pending, 0);
> > + if (atomic_read(&stats->reset_pending))
> > + bool pending = atomic_read(&stats->reset_pending);
> > + atomic_set(&stats->reset_pending, 1);
> > + bool pending = atomic_read(&stats->reset_pending);
> > + if (atomic_read(&stats->reset_pending))
>
> What do you think atomic_t is doing for you?

I was trying to avoid races while two writes are going in parallel,
but obviously as this isn't a RMW operation, it won't result in
anything for me.

Maybe what I should be doing is just READ_ONCE()/WRITE_ONCE()? So the
other side doesn't see any intermediate value that was never meant to
be set/read ?

--
viresh