linux-kernel - Re: [PATCH 1/1, v6] cgroup/freezer: add per freezer duty ratio control

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Message-ID: <4D533EB0.6060405@cn.fujitsu.com>
Date:	Thu, 10 Feb 2011 09:26:08 +0800
From:	Li Zefan <lizf@...fujitsu.com>
To:	jacob pan <jacob.jun.pan@...ux.intel.com>
CC:	LKML <linux-kernel@...r.kernel.org>,
	"Kirill A. Shutemov" <kirill@...temov.name>,
	Arjan van de Ven <arjan@...ux.intel.com>,
	Matt Helsley <matthltc@...ibm.com>,
	container cgroup <containers@...ts.linux-foundation.org>,
	Paul Menage <menage@...gle.com>, akpm@...ux-foundation.org,
	rdunlap@...otime.net, Cedric Le Goater <clg@...ibm.com>
Subject: Re: [PATCH 1/1, v6] cgroup/freezer: add per freezer duty ratio control

jacob pan wrote:
> On Wed, 09 Feb 2011 11:07:59 +0800
> Li Zefan <lizf@...fujitsu.com> wrote:
> 
>> jacob.jun.pan@...ux.intel.com wrote:
>>> From: Jacob Pan <jacob.jun.pan@...ux.intel.com>
>>>
>>> Freezer subsystem is used to manage batch jobs which can start
>>> stop at the same time. However, sometime it is desirable to let
>>> the kernel manage the freezer state automatically with a given
>>> duty ratio.
>>> For example, if we want to reduce the time that backgroup apps
>>> are allowed to run we can put them into a freezer subsystem and
>>> set the kernel to turn them THAWED/FROZEN at given duty ratio.
>>>
>>> This patch introduces two file nodes under cgroup
>>> freezer.duty_ratio_pct and freezer.period_sec
>>>
>>> Usage example: set period to be 5 seconds and frozen duty ratio 90%
>>> [root@...alhost aoa]# echo 90 > freezer.duty_ratio_pct
>>> [root@...alhost aoa]# echo 5000 > freezer.period_ms
>>>
>>
>> So after:
>>
>> # echo FROZEN > freezer.state
>> # echo 90 > freezer.duty_ratio_pct
>> # echo 5000 > freezer.period_ms
>> ...
>> # echo 0 > freezer.duty_ratio_pct
>>
>> All the tasks in this cgroup are in THAWED state, but the cgroup is
>> in FROZEN state. This should be fixed.
> I don't know how could this ever happen. Is it based on your testing?
> Whenever tasks in a cgroup are thawed/frozen, its freezer state would
> change accordingly.
> After your example, freezer.state should have THAWED. It matches
> user's intention, i.e. if a user do
> echo 0 > freezer.duty_ratio_pct
> It must want 0% to be frozen, which is THAWED.
> 
> Am I missing anything?
> 

You're right. I made a mistake when looking into the patch.

btw, I made a few other comments in your code, that you may have
overlooked.
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