From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Xiaoguang Chen <chenxg.marvell@gmail.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
Xiaoguang Chen <chenxg@marvell.com>,
cpufreq@vger.kernel.org, linux-pm@vger.kernel.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
njiang1@marvell.com, zjwu@marvell.com, ylmao@marvell.com
Subject: Re: [PATCH v5] cpufreq: fix governor start/stop race condition
Date: Thu, 20 Jun 2013 00:50:44 +0200 [thread overview]
Message-ID: <10398431.HfgFiK9AG8@vostro.rjw.lan> (raw)
In-Reply-To: <CAFgnuDdN6CoLCvH6-d9YB=-jm-ESC1s__si970pa10mC3wsCdw@mail.gmail.com>
On Wednesday, June 19, 2013 11:26:13 AM Xiaoguang Chen wrote:
> 2013/6/19 Viresh Kumar <viresh.kumar@linaro.org>:
> > On 19 June 2013 08:43, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> >> On 19 June 2013 06:50, Xiaoguang Chen <chenxg.marvell@gmail.com> wrote:
> >>> 2013/6/19 Rafael J. Wysocki <rjw@sisk.pl>:
> >>
> >>>>> 2) Current governor is userspace, now cpu0 hotplugs in cpu3, it will
> >>>>
> >>>> Can you please tell me what the above is supposed to mean? Is it supposed to
> >>>> mean "the online of cpu3 is being run on cpu0" or something different? If
> >>>> something different, then what?
>
> Sorry I missed this question, Let me explain it in detail
> Suppose we are in such condtition, current cpufreq goveror is
> userspace governor. cpu3 is offline.
> and two things happen as above two cases, first thing is application
> tries to change current governor to ondemand governor,
> second thing is cpu0 tries to make cpu3 online which is off line
> before. both of these two cases will try to stop current governor and
> start a governor. if above two things interleave, unexpected behavior
> will happen.
Now it's clear, thanks for the explanation. [Well, I'll still need to fix up
the changelog. Sigh.]
Thanks,
Rafael
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
prev parent reply other threads:[~2013-06-19 22:41 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-13 9:01 Xiaoguang Chen
2013-06-13 9:16 ` Viresh Kumar
2013-06-13 10:03 ` Xiaoguang Chen
2013-06-19 0:25 ` Rafael J. Wysocki
2013-06-19 1:20 ` Xiaoguang Chen
2013-06-19 3:00 ` Viresh Kumar
2013-06-19 22:49 ` Rafael J. Wysocki
2013-06-20 3:46 ` Viresh Kumar
2013-06-19 3:13 ` Viresh Kumar
2013-06-19 3:15 ` Viresh Kumar
2013-06-19 3:26 ` Xiaoguang Chen
2013-06-19 22:50 ` Rafael J. Wysocki [this message]
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