LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Viresh Kumar <viresh.kumar@linaro.org>
To: Juri Lelli <juri.lelli@redhat.com>
Cc: rafael.j.wysocki@intel.com, peterz@infradead.org,
	linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	Ingo Molnar <mingo@redhat.com>,
	Claudio Scordino <claudio@evidence.eu.com>,
	Luca Abeni <luca.abeni@santannapisa.it>
Subject: Re: [PATCH] kernel/sched/cpufreq_schedutil: remove stale comment
Date: Wed, 9 May 2018 14:11:54 +0530	[thread overview]
Message-ID: <20180509084154.dbbhkegrengsw3ki@vireshk-i7> (raw)
In-Reply-To: <20180509084051.12107-1-juri.lelli@redhat.com>

On 09-05-18, 10:40, Juri Lelli wrote:
> After commit 794a56ebd9a57 ("sched/cpufreq: Change the worker kthread to
> SCHED_DEADLINE") schedutil kthreads are "ignored" for a clock frequency
> selection point of view, so the potential corner case for RT tasks is not
> possible at all now.
> 
> Remove the stale comment mentioning it.
> 
> Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
> Cc: Viresh Kumar <viresh.kumar@linaro.org>
> Cc: Claudio Scordino <claudio@evidence.eu.com>
> Cc: Luca Abeni <luca.abeni@santannapisa.it>
> ---
>  kernel/sched/cpufreq_schedutil.c | 13 -------------
>  1 file changed, 13 deletions(-)
> 
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index d2c6083304b4..23ef19070137 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -396,19 +396,6 @@ static void sugov_irq_work(struct irq_work *irq_work)
>  
>  	sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
>  
> -	/*
> -	 * For RT tasks, the schedutil governor shoots the frequency to maximum.
> -	 * Special care must be taken to ensure that this kthread doesn't result
> -	 * in the same behavior.
> -	 *
> -	 * This is (mostly) guaranteed by the work_in_progress flag. The flag is
> -	 * updated only at the end of the sugov_work() function and before that
> -	 * the schedutil governor rejects all other frequency scaling requests.
> -	 *
> -	 * There is a very rare case though, where the RT thread yields right
> -	 * after the work_in_progress flag is cleared. The effects of that are
> -	 * neglected for now.
> -	 */
>  	kthread_queue_work(&sg_policy->worker, &sg_policy->work);
>  }

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh

  reply	other threads:[~2018-05-09  8:42 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-09  8:40 Juri Lelli
2018-05-09  8:41 ` Viresh Kumar [this message]
2018-05-13  8:40   ` Rafael J. Wysocki

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180509084154.dbbhkegrengsw3ki@vireshk-i7 \
    --to=viresh.kumar@linaro.org \
    --cc=claudio@evidence.eu.com \
    --cc=juri.lelli@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=luca.abeni@santannapisa.it \
    --cc=mingo@redhat.com \
    --cc=peterz@infradead.org \
    --cc=rafael.j.wysocki@intel.com \
    --subject='Re: [PATCH] kernel/sched/cpufreq_schedutil: remove stale comment' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).