Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230522145702.2419654-1-lukasz.luba@arm.com> <20230522145702.2419654-3-lukasz.luba@arm.com>
In-Reply-To: <20230522145702.2419654-3-lukasz.luba@arm.com>
From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Tue, 20 Jun 2023 19:36:36 +0200
Message-ID: <CAJZ5v0i+iY-xknvEZn8Se06XS3Cqyqo3p=fYcsLoFBQ7geKRHA@mail.gmail.com>
Subject: Re: [RESEND][PATCH v2 2/3] cpufreq: schedutil: Refactor
 sugov_update_shared() internals
To:     Lukasz Luba <lukasz.luba@arm.com>
Cc:     linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
        rafael@kernel.org, linux-pm@vger.kernel.org, rostedt@goodmis.org,
        mhiramat@kernel.org, mingo@redhat.com, peterz@infradead.org,
        juri.lelli@redhat.com, vincent.guittot@linaro.org,
        dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de,
        bristot@redhat.com, vschneid@redhat.com, delyank@fb.com,
        qyousef@google.com, qyousef@layalina.io
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8BIT
Precedence: bulk

On Mon, May 22, 2023 at 4:57 PM Lukasz Luba <lukasz.luba@arm.com> wrote:
>
> Remove the if section block. Use the simple check to bail out
> and jump to the unlock at the end. That makes the code more readable
> and ready for some future tracing.
>
> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
> ---
>  kernel/sched/cpufreq_schedutil.c | 20 +++++++++++---------
>  1 file changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index e3211455b203..f462496e5c07 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -446,17 +446,19 @@ sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags)
>
>         ignore_dl_rate_limit(sg_cpu);
>
> -       if (sugov_should_update_freq(sg_policy, time)) {
> -               next_f = sugov_next_freq_shared(sg_cpu, time);
> +       if (!sugov_should_update_freq(sg_policy, time))
> +               goto unlock;
>
> -               if (!sugov_update_next_freq(sg_policy, time, next_f))
> -                       goto unlock;
> +       next_f = sugov_next_freq_shared(sg_cpu, time);
> +
> +       if (!sugov_update_next_freq(sg_policy, time, next_f))
> +               goto unlock;
> +
> +       if (sg_policy->policy->fast_switch_enabled)
> +               cpufreq_driver_fast_switch(sg_policy->policy, next_f);
> +       else
> +               sugov_deferred_update(sg_policy);
>
> -               if (sg_policy->policy->fast_switch_enabled)
> -                       cpufreq_driver_fast_switch(sg_policy->policy, next_f);
> -               else
> -                       sugov_deferred_update(sg_policy);
> -       }
>  unlock:
>         raw_spin_unlock(&sg_policy->update_lock);
>  }
> --

The first patch in the series needs some feedback from the scheduler
people, but I can apply this one right away if you want me to.