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From: Juri Lelli <juri.lelli@redhat.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Linux PM <linux-pm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Joel Fernandes <joel@joelfernandes.org>,
	Patrick Bellasi <patrick.bellasi@arm.com>,
	claudio@evidence.eu.com, Todd Kjos <tkjos@google.com>
Subject: Re: [PATCH] cpufreq: schedutil: Avoid missing updates for one-CPU policies
Date: Wed, 23 May 2018 12:13:44 +0200	[thread overview]
Message-ID: <20180523101344.GB30909@localhost.localdomain> (raw)
In-Reply-To: <1672734.JYOlA1IWnU@aspire.rjw.lan>

On 23/05/18 11:47, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> Commit 152db033d775 (schedutil: Allow cpufreq requests to be made
> even when kthread kicked) made changes to prevent utilization updates
> from being discarded during processing a previous request, but it
> left a small window in which that still can happen in the one-CPU
> policy case.  Namely, updates coming in after setting work_in_progress
> in sugov_update_commit() and clearing it in sugov_work() will still
> be dropped due to the work_in_progress check in sugov_update_single().
> 
> To close that window, rearrange the code so as to acquire the update
> lock around the deferred update branch in sugov_update_single()
> and drop the work_in_progress check from it.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

I don't have a platform at hand where to test this. But, it looks OK to
me.

Reviewed-by: Juri Lelli <juri.lelli@redhat.com>

Best,

- Juri

  reply	other threads:[~2018-05-23 10:13 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-23  9:47 [PATCH] cpufreq: schedutil: Avoid missing updates for one-CPU policies Rafael J. Wysocki
2018-05-23 10:13 ` Juri Lelli [this message]
2018-05-23 10:14 ` Viresh Kumar
2018-05-24  0:56 ` Joel Fernandes

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