linux-kernel - Re: [PATCH V4 1/3] sched: cpufreq: Allow remote cpufreq callbacks

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Date:   Thu, 27 Jul 2017 08:53:27 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Len Brown <lenb@...nel.org>, Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        smuckle.linux@...il.com, juri.lelli@....com,
        Morten.Rasmussen@....com, patrick.bellasi@....com,
        eas-dev@...ts.linaro.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V4 1/3] sched: cpufreq: Allow remote cpufreq callbacks

On 26-07-17, 19:42, Rafael J. Wysocki wrote:
> On Wednesday, July 26, 2017 02:52:32 PM Viresh Kumar wrote:

> > +	/* Don't allow remote callbacks */
> > +	if (smp_processor_id() != data->cpu)
> > +		return;
> 
> You can do this check against cpu->cpu, however.
> 
> > +	/* Don't allow remote callbacks */
> > +	if (smp_processor_id() != data->cpu)
> > +		return;
> 
> And same here.
> 
> > +
> >  	if (flags & SCHED_CPUFREQ_IOWAIT) {
> >  		cpu->iowait_boost = int_tofp(1);
> >  	} else if (cpu->iowait_boost) {
> > diff --git a/include/linux/sched/cpufreq.h b/include/linux/sched/cpufreq.h
> > index d2be2ccbb372..8256a8f35f22 100644
> > --- a/include/linux/sched/cpufreq.h
> > +++ b/include/linux/sched/cpufreq.h
> > @@ -16,6 +16,7 @@
> >  #ifdef CONFIG_CPU_FREQ
> >  struct update_util_data {
> >         void (*func)(struct update_util_data *data, u64 time, unsigned int flags);
> > +       unsigned int cpu;
> 
> So it looks like you don't need this.
> 
> schedutil doesn't need it as per patch [2/3].

Hmm, so your comments are exactly same as what Peter suggested few
days back.

sugov_get_util() uses it in 2/3, as we need to know the target CPU
anyway.

But I think it would be better to add the cpu variable in sugov_cpu
structure instead as only schedutil needs it. I will do that change
and send V5.

-- 
viresh