linux-kernel - Re: [RFC] oom-kill: give the dying task a higher priority

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Message-ID: <20100527183319.GA22313@redhat.com>
Date:	Thu, 27 May 2010 20:33:19 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	"Luis Claudio R. Goncalves" <lclaudio@...g.org>
Cc:	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Thomas Gleixner <tglx@...utronix.de>,
	Peter Zijlstra <peterz@...radead.org>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	David Rientjes <rientjes@...gle.com>,
	Mel Gorman <mel@....ul.ie>, williams@...hat.com
Subject: Re: [RFC] oom-kill: give the dying task a higher priority

On 05/27, Luis Claudio R. Goncalves wrote:
>
> It sounds plausible giving the dying task an even higher priority to be
> sure it will be scheduled sooner and free the desired memory.

As usual, I can't really comment the changes in oom logic, just minor
nits...

> @@ -413,6 +415,8 @@ static void __oom_kill_task(struct task_struct *p, int verbose)
>  	 */
>  	p->rt.time_slice = HZ;
>  	set_tsk_thread_flag(p, TIF_MEMDIE);
> +	param.sched_priority = MAX_RT_PRIO-1;
> +	sched_setscheduler(p, SCHED_FIFO, &param);
>
>  	force_sig(SIGKILL, p);

Probably sched_setscheduler_nocheck() makes more sense.

Minor, but perhaps it would be a bit better to send SIGKILL first,
then raise its prio.

Oleg.

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