From: Peter Zijlstra <peterz@infradead.org>
To: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: rjw@rjwysocki.net, linux-kernel@vger.kernel.org,
Viresh Kumar <viresh.kumar@linaro.org>,
Eduardo Valentin <edubezval@gmail.com>,
Javi Merino <javi.merino@kernel.org>,
Leo Yan <leo.yan@linaro.org>,
Kevin Wangtao <kevin.wangtao@linaro.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Rui Zhang <rui.zhang@intel.com>,
Daniel Thompson <daniel.thompson@linaro.org>,
"open list:POWER MANAGEMENT CORE" <linux-pm@vger.kernel.org>
Subject: Re: [PATCH V5] powercap/drivers/idle_injection: Add an idle injection framework
Date: Thu, 7 Jun 2018 10:32:29 +0200 [thread overview]
Message-ID: <20180607083229.GJ12198@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <ea347237-7cef-095a-5ddb-19c181d10c23@linaro.org>
On Thu, Jun 07, 2018 at 10:18:27AM +0200, Daniel Lezcano wrote:
> So IIUC, neither atomic or WRITE|READ_ONCE are necessary in this code
> because of the wake_up_process() barrier is enough, right ?
I didn't look hard enough; if there ever is a time where the loads and
stores happen concurrently, you need READ/WRITE_ONCE(). If there is no
concurrency on the variables, you don't need anything.
Neither atomic_read/set() nor REAd/WRITE_ONCE() will help with ordering,
which is what the wake_up_process() would provide here, different things
entirely.
next prev parent reply other threads:[~2018-06-07 8:32 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-05 9:16 [PATCH V5] powercap/drivers/idle_injection: Add an idle injection framework Daniel Lezcano
2018-06-05 10:39 ` Viresh Kumar
2018-06-05 14:54 ` Daniel Lezcano
2018-06-06 4:27 ` Viresh Kumar
2018-06-06 10:22 ` Daniel Lezcano
2018-06-06 10:45 ` Viresh Kumar
2018-06-06 12:05 ` Andrea Parri
2018-06-06 12:29 ` Peter Zijlstra
2018-06-07 14:11 ` Daniel Lezcano
2018-06-08 4:48 ` Viresh Kumar
2018-06-08 8:31 ` Daniel Lezcano
2018-06-06 12:23 ` Peter Zijlstra
2018-06-06 13:42 ` Daniel Lezcano
2018-06-06 15:02 ` Peter Zijlstra
2018-06-07 8:18 ` Daniel Lezcano
2018-06-07 8:32 ` Peter Zijlstra [this message]
2018-06-07 8:42 ` Viresh Kumar
2018-06-07 8:46 ` Daniel Lezcano
2018-06-07 8:49 ` Viresh Kumar
2018-06-07 9:09 ` Daniel Lezcano
2018-06-07 9:32 ` Peter Zijlstra
2018-06-07 9:39 ` Peter Zijlstra
2018-06-07 12:31 ` Daniel Lezcano
2018-06-07 9:09 ` Peter Zijlstra
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