linux-kernel - Re: [PATCH 04/14] sched: cpufreq: Move sched_cpufreq_governor

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Message-ID: <20200508053523.GH19464@codeaurora.org>
Date:   Fri, 8 May 2020 11:05:23 +0530
From:   Pavan Kondeti <pkondeti@...eaurora.org>
To:     Quentin Perret <qperret@...gle.com>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, x86@...nel.org,
        hpa@...or.com, sudeep.holla@....com, gregkh@...uxfoundation.org,
        rafael@...nel.org, viresh.kumar@...aro.org, peterz@...radead.org,
        juri.lelli@...hat.com, vincent.guittot@...aro.org,
        dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
        mgorman@...e.de, mcgrof@...nel.org, keescook@...omium.org,
        yzaikin@...gle.com, fweisbec@...il.com, tkjos@...gle.com,
        kernel-team@...roid.com
Subject: Re: [PATCH 04/14] sched: cpufreq: Move
 sched_cpufreq_governor_change()

On Thu, May 07, 2020 at 07:10:02PM +0100, Quentin Perret wrote:
> CPUFreq calls into sched_cpufreq_governor_change() when switching
> governors, which triggers a sched domain rebuild when entering or
> exiting schedutil.
> 
> Move the function to sched/cpufreq.c to prepare the ground for the
> modularization of schedutil.
> 
> Signed-off-by: Quentin Perret <qperret@...gle.com>
> ---
>  kernel/sched/cpufreq.c           | 33 ++++++++++++++++++++++++++++++++
>  kernel/sched/cpufreq_schedutil.c | 33 --------------------------------
>  2 files changed, 33 insertions(+), 33 deletions(-)
> 
> diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c
> index 7c2fe50fd76d..82f2dda61a55 100644
> --- a/kernel/sched/cpufreq.c
> +++ b/kernel/sched/cpufreq.c
> @@ -75,3 +75,36 @@ bool cpufreq_this_cpu_can_update(struct cpufreq_policy *policy)
>  		(policy->dvfs_possible_from_any_cpu &&
>  		 rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data)));
>  }
> +
> +#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);
> +}
> +static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn);
> +
> +/*
> + * EAS shouldn't be attempted without sugov, so rebuild the sched_domains
> + * on governor changes to make sure the scheduler knows about it.
> + */

In the previous patch, you removed reference to schedutil and replaced it with
" an EAS-compatible CPUfreq governor (schedutil)". May be you could do the
same here.

Thanks,
Pavan

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