Re: [PATCH 1/4] cpufreq: Add a cpufreq pressure feedback for the scheduler

From: Vincent Guittot
Date: Thu Dec 14 2023 - 06:06:40 EST


On Thu, 14 Dec 2023 at 10:20, Lukasz Luba <lukasz.luba@xxxxxxx> wrote:
>
>
>
> On 12/12/23 14:27, Vincent Guittot wrote:
> > Provide to the scheduler a feedback about the temporary max available
> > capacity. Unlike arch_update_thermal_pressure, this doesn't need to be
> > filtered as the pressure will happen for dozens ms or more.
> >
> > Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
> > ---
> > drivers/cpufreq/cpufreq.c | 48 +++++++++++++++++++++++++++++++++++++++
> > include/linux/cpufreq.h | 10 ++++++++
> > 2 files changed, 58 insertions(+)
> >
> > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> > index 44db4f59c4cc..7d5f71be8d29 100644
> > --- a/drivers/cpufreq/cpufreq.c
> > +++ b/drivers/cpufreq/cpufreq.c
> > @@ -2563,6 +2563,50 @@ int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
> > }
> > EXPORT_SYMBOL(cpufreq_get_policy);
> >
> > +DEFINE_PER_CPU(unsigned long, cpufreq_pressure);
> > +EXPORT_PER_CPU_SYMBOL_GPL(cpufreq_pressure);
>
> Why do we export this variable when we have get/update functions?
> Do we expect modules would manipulate those per-cpu variables
> independently and not like we do per-cpumask in the update func.?

No, I will remove the EXPORT_PER_CPU_SYMBOL_GPL