Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work with timers

From	"Rafael J. Wysocki" <rjw@rjwysocki.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work with timers
Date	2015-12-07 23:50 +0100
Message-ID	<qDcLw-2nc-5@gated-at.bofh.it> (permalink)
References	<qBtnr-8mi-3@gated-at.bofh.it> <qCYSd-1zG-7@gated-at.bofh.it> <qDciu-2cp-21@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Monday, December 07, 2015 11:43:50 PM Rafael J. Wysocki wrote:
> On Monday, December 07, 2015 01:20:27 PM Viresh Kumar wrote:
> > On 07-12-15, 02:28, Rafael J. Wysocki wrote:
> > > What about if that happens in parallel with the decrementation in
> > > dbs_work_handler()?
> > > 
> > > Is there anything preventing that from happening?
> > 
> > Hmmm, you are right. Following is required for that.
> > 
> > diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
> > index c9e420bd0eec..d8a89e653933 100644
> > --- a/drivers/cpufreq/cpufreq_governor.c
> > +++ b/drivers/cpufreq/cpufreq_governor.c
> > @@ -230,6 +230,7 @@ static void dbs_work_handler(struct work_struct *work)
> >         struct dbs_data *dbs_data;
> >         unsigned int sampling_rate, delay;
> >         bool eval_load;
> > +       unsigned long flags;
> >  
> >         policy = shared->policy;
> >         dbs_data = policy->governor_data;
> > @@ -257,7 +258,10 @@ static void dbs_work_handler(struct work_struct *work)
> >         delay = dbs_data->cdata->gov_dbs_timer(policy, eval_load);
> >         mutex_unlock(&shared->timer_mutex);
> >  
> > +       spin_lock_irqsave(&shared->timer_lock, flags);
> >         shared->skip_work--;
> > +       spin_unlock_irqrestore(&shared->timer_lock, flags);
> > +
> >         gov_add_timers(policy, delay);
> >  }
> 
> OK, so can you please send an updated patch with the above change folded in?

In fact, I've already folded the above changes into the $subject patch (but this
is an exception).

I'll send the "atomic" changes separately.

Thanks,
Rafael

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Thread

[PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work with timers Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-03 05:10 +0100
  Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work with timers "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-04 01:50 +0100
    Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work  with timers Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-04 07:20 +0100
      Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work with timers "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-05 02:50 +0100
        Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work  with timers Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-05 05:20 +0100
          Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work with timers "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-07 02:00 +0100
            Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work  with timers Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-07 09:00 +0100
              Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work with timers "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-07 23:20 +0100
                Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work with timers "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-07 23:50 +0100
                [PATCH][experimantal] cpufreq: governor: Use an atomic variable for synchronization "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-08 01:20 +0100
                Re: [PATCH][experimantal] cpufreq: governor: Use an atomic variable  for synchronization Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-08 08:00 +0100
                Re: [PATCH][experimantal] cpufreq: governor: Use an atomic variable for synchronization "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-08 14:10 +0100
                Re: [PATCH][experimantal] cpufreq: governor: Use an atomic variable  for synchronization Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-08 14:40 +0100
                Re: [PATCH][experimantal] cpufreq: governor: Use an atomic variable for synchronization "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-08 14:50 +0100
                Re: [PATCH][experimantal] cpufreq: governor: Use an atomic variable  for synchronization Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-08 15:00 +0100
                Re: [PATCH][experimantal] cpufreq: governor: Use an atomic variable for synchronization "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-08 15:10 +0100
                Re: [PATCH][experimantal] cpufreq: governor: Use an atomic variable  for synchronization Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-08 16:00 +0100
                Re: [PATCH][experimantal] cpufreq: governor: Use an atomic variable for synchronization "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-08 17:20 +0100
                Re: [PATCH][experimantal] cpufreq: governor: Use an atomic variable  for synchronization Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-08 17:40 +0100
                Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work  with timers Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-08 07:50 +0100
                Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work  with timers Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-08 08:00 +0100
                Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work with timers "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-08 13:50 +0100
                Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work  with timers Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-08 14:40 +0100
                Re: [PATCH V2 5/6] cpufreq: governor: replace per-cpu delayed work with timers "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-08 14:40 +0100
  [PATCH V3 5/6] cpufreq: governor: replace per-cpu delayed work with timers Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-04 07:20 +0100
    [PATCH V4 5/6] cpufreq: governor: replace per-cpu delayed work with timers Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-09 03:10 +0100
      Re: [PATCH V4 5/6] cpufreq: governor: replace per-cpu delayed work with timers "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-09 22:40 +0100
        Re: [PATCH V4 5/6] cpufreq: governor: replace per-cpu delayed work  with timers Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-10 03:40 +0100
          Re: [PATCH V4 5/6] cpufreq: governor: replace per-cpu delayed work with timers "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-10 22:50 +0100
            Re: [PATCH V4 5/6] cpufreq: governor: replace per-cpu delayed work  with timers Viresh Kumar <viresh.kumar@linaro.org> - 2015-12-11 02:50 +0100

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