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

Rafael J. Wysocki
2015-12-07T22:47:21Z

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