Re: [PATCH V4 2/4] cpufreq: intel_pstate: Migrate to ->offline() instead of ->stop_cpu()

From: Rafael J. Wysocki
Date: Wed Jun 30 2021 - 12:59:18 EST


On Thu, Jun 24, 2021 at 3:52 AM Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
>
> On 23-06-21, 17:13, Rafael J. Wysocki wrote:
> > As mentioned already in
> >
> > https://lore.kernel.org/linux-pm/CAJZ5v0g2tCZptcqh+c55YYiO7rDHmZivMLsmpq_7005zNPN1xg@xxxxxxxxxxxxxx/
>
> Sorry about failing to reply over that, I got confused somehow..
>
> > this isn't particularly clean, because intel_pstate_cpu_offline() is
> > also used in the passive mode where the above call is not needed.
>
> intel_pstate_clear_update_util_hook() returns early if the hook was never
> registered, and so calling it was safe, but yes not very clean.
>
> > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > Subject: [PATCH] cpufreq: intel_pstate: Combine ->stop_cpu() and ->offline()
> >
> > Combine the ->stop_cpu() and ->offline() callback routines for the
> > active mode of intel_pstate so as to avoid setting the ->stop_cpu
> > callback pointer which is going to be dropped from the framework.
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > ---
> > drivers/cpufreq/intel_pstate.c | 7 ++++---
> > 1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > Index: linux-pm/drivers/cpufreq/intel_pstate.c
> > ===================================================================
> > --- linux-pm.orig/drivers/cpufreq/intel_pstate.c
> > +++ linux-pm/drivers/cpufreq/intel_pstate.c
> > @@ -2577,11 +2577,13 @@ static int intel_pstate_cpu_online(struc
> > return 0;
> > }
> >
> > -static void intel_pstate_stop_cpu(struct cpufreq_policy *policy)
> > +static int intel_pstate_stop_cpu(struct cpufreq_policy *policy)
> > {
> > pr_debug("CPU %d stopping\n", policy->cpu);
> >
> > intel_pstate_clear_update_util_hook(policy->cpu);
> > +
> > + return intel_pstate_cpu_offline(policy);
> > }
> >
> > static int intel_pstate_cpu_exit(struct cpufreq_policy *policy)
> > @@ -2654,8 +2656,7 @@ static struct cpufreq_driver intel_pstat
> > .resume = intel_pstate_resume,
> > .init = intel_pstate_cpu_init,
> > .exit = intel_pstate_cpu_exit,
> > - .stop_cpu = intel_pstate_stop_cpu,
> > - .offline = intel_pstate_cpu_offline,
> > + .offline = intel_pstate_stop_cpu,
>
> I would suggest to rename intel_pstate_cpu_offline() as
> intel_cpufreq_cpu_offline() and intel_pstate_stop_cpu() as
> intel_pstate_cpu_offline(), so we remove the stop-cpu terminology completely.

I have followed the above suggestion and applied the modified patch
along with the rest of this series.

> Either way:
> Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>

Thanks!

> > .online = intel_pstate_cpu_online,
> > .update_limits = intel_pstate_update_limits,
> > .name = "intel_pstate",