[RESEND,v2,1/3] sched/topology,schedutil: wrap sched domains rebuild

Add the rebuild_sched_domains_energy() function to wrap the functionality
that rebuilds the scheduling domains if any of the Energy Aware Scheduling
(EAS) initialisation conditions change. This functionality is used when
schedutil is added or removed or when EAS is enabled or disabled
through the sched_energy_aware sysctl.

Therefore, create a single function that is used in both these cases and
that can be later reused.

Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Quentin Perret <qperret@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
---
 include/linux/sched/topology.h   |  8 ++++++++
 kernel/sched/cpufreq_schedutil.c |  9 +--------
 kernel/sched/topology.c          | 18 +++++++++++-------
 3 files changed, 20 insertions(+), 15 deletions(-)

On Tue, Oct 27, 2020 at 7:08 PM Ionela Voinescu <ionela.voinescu@arm.com> wrote:
>
> Add the rebuild_sched_domains_energy() function to wrap the functionality
> that rebuilds the scheduling domains if any of the Energy Aware Scheduling
> (EAS) initialisation conditions change. This functionality is used when
> schedutil is added or removed or when EAS is enabled or disabled
> through the sched_energy_aware sysctl.
>
> Therefore, create a single function that is used in both these cases and
> that can be later reused.
>
> Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
> Acked-by: Quentin Perret <qperret@google.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
> Cc: Viresh Kumar <viresh.kumar@linaro.org>

For the schedutil part:

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

and I'm assuming the patch to be taken care of by Peter.

> ---
>  include/linux/sched/topology.h   |  8 ++++++++
>  kernel/sched/cpufreq_schedutil.c |  9 +--------
>  kernel/sched/topology.c          | 18 +++++++++++-------
>  3 files changed, 20 insertions(+), 15 deletions(-)
>
> diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
> index 9ef7bf686a9f..8f0f778b7c91 100644
> --- a/include/linux/sched/topology.h
> +++ b/include/linux/sched/topology.h
> @@ -225,6 +225,14 @@ static inline bool cpus_share_cache(int this_cpu, int that_cpu)
>
>  #endif /* !CONFIG_SMP */
>
> +#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
> +extern void rebuild_sched_domains_energy(void);
> +#else
> +static inline void rebuild_sched_domains_energy(void)
> +{
> +}
> +#endif
> +
>  #ifndef arch_scale_cpu_capacity
>  /**
>   * arch_scale_cpu_capacity - get the capacity scale factor of a given CPU.
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index e254745a82cb..37b303890336 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -899,16 +899,9 @@ struct cpufreq_governor *cpufreq_default_governor(void)
>  cpufreq_governor_init(schedutil_gov);
>
>  #ifdef CONFIG_ENERGY_MODEL
> -extern bool sched_energy_update;
> -extern struct mutex sched_energy_mutex;
> -
>  static void rebuild_sd_workfn(struct work_struct *work)
>  {
> -       mutex_lock(&sched_energy_mutex);
> -       sched_energy_update = true;
> -       rebuild_sched_domains();
> -       sched_energy_update = false;
> -       mutex_unlock(&sched_energy_mutex);
> +       rebuild_sched_domains_energy();
>  }
>  static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn);
>
> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
> index dd7770226086..270bafb73506 100644
> --- a/kernel/sched/topology.c
> +++ b/kernel/sched/topology.c
> @@ -211,6 +211,15 @@ unsigned int sysctl_sched_energy_aware = 1;
>  DEFINE_MUTEX(sched_energy_mutex);
>  bool sched_energy_update;
>
> +void rebuild_sched_domains_energy(void)
> +{
> +       mutex_lock(&sched_energy_mutex);
> +       sched_energy_update = true;
> +       rebuild_sched_domains();
> +       sched_energy_update = false;
> +       mutex_unlock(&sched_energy_mutex);
> +}
> +
>  #ifdef CONFIG_PROC_SYSCTL
>  int sched_energy_aware_handler(struct ctl_table *table, int write,
>                 void *buffer, size_t *lenp, loff_t *ppos)
> @@ -223,13 +232,8 @@ int sched_energy_aware_handler(struct ctl_table *table, int write,
>         ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
>         if (!ret && write) {
>                 state = static_branch_unlikely(&sched_energy_present);
> -               if (state != sysctl_sched_energy_aware) {
> -                       mutex_lock(&sched_energy_mutex);
> -                       sched_energy_update = 1;
> -                       rebuild_sched_domains();
> -                       sched_energy_update = 0;
> -                       mutex_unlock(&sched_energy_mutex);
> -               }
> +               if (state != sysctl_sched_energy_aware)
> +                       rebuild_sched_domains_energy();
>         }
>
>         return ret;
> --
> 2.17.1
>

Hi Rafael,

On Friday 30 Oct 2020 at 16:26:32 (+0100), Rafael J. Wysocki wrote:
> On Tue, Oct 27, 2020 at 7:08 PM Ionela Voinescu <ionela.voinescu@arm.com> wrote:
> >
> > Add the rebuild_sched_domains_energy() function to wrap the functionality
> > that rebuilds the scheduling domains if any of the Energy Aware Scheduling
> > (EAS) initialisation conditions change. This functionality is used when
> > schedutil is added or removed or when EAS is enabled or disabled
> > through the sched_energy_aware sysctl.
> >
> > Therefore, create a single function that is used in both these cases and
> > that can be later reused.
> >
> > Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
> > Acked-by: Quentin Perret <qperret@google.com>
> > Cc: Ingo Molnar <mingo@redhat.com>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
> > Cc: Viresh Kumar <viresh.kumar@linaro.org>
> 
> For the schedutil part:
> 
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 

Thank you for taking a look!

> and I'm assuming the patch to be taken care of by Peter.

I'm hoping that as well. I'll ask some of the arm64 folk to take another
look over 2/3 to make sure that's covered.

Many thanks,
Ionela.