linux-kernel - Re: [PATCH] oom: skip frozen tasks

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Message-ID: <4E579541.6060607@openvz.org>
Date:	Fri, 26 Aug 2011 16:44:49 +0400
From:	Konstantin Khlebnikov <khlebnikov@...nvz.org>
To:	Michal Hocko <mhocko@...e.cz>
CC:	David Rientjes <rientjes@...gle.com>,
	Oleg Nesterov <oleg@...hat.com>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>
Subject: Re: [PATCH] oom: skip frozen tasks

Michal Hocko wrote:
> On Fri 26-08-11 14:03:17, Konstantin Khlebnikov wrote:
>> Michal Hocko wrote:
>>
>>> @@ -450,6 +459,10 @@ static int oom_kill_task(struct task_struct *p, struct mem_cgroup *mem)
>>>   			pr_err("Kill process %d (%s) sharing same memory\n",
>>>   				task_pid_nr(q), q->comm);
>>>   			task_unlock(q);
>>> +
>>> +			if (frozen(q))
>>> +				thaw_process(q);
>>> +
>>
>> We must thaw task strictly after sending SIGKILL.
>
> Sounds reasonable.
>
>> But anyway I think this is a bad idea.
>
> Why?

Refrigerator may be used for digging in task's internal structures,
so such digger may be very surprised if somebody suddenly thaws this task.

>
>>
>>>   			force_sig(SIGKILL, q);
>>>   		}
>>>
>

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