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Date: Fri, 18 Sep 2015 21:07:25 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: Christoph Lameter <cl@linux.com>
Cc: Kyle Walker <kwalker@redhat.com>, akpm@linux-foundation.org,
        mhocko@suse.cz, rientjes@google.com, hannes@cmpxchg.org,
        vdavydov@parallels.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
        Stanislav Kozina <skozina@redhat.com>
Subject: Re: [PATCH] mm/oom_kill.c: don't kill TASK_UNINTERRUPTIBLE tasks
Message-ID: <20150918190725.GA24989@redhat.com>
References: <1442512783-14719-1-git-send-email-kwalker@redhat.com> <20150917192204.GA2728@redhat.com> <alpine.DEB.2.11.1509181035180.11189@east.gentwo.org> <20150918162423.GA18136@redhat.com> <alpine.DEB.2.11.1509181200140.11964@east.gentwo.org>
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On 09/18, Christoph Lameter wrote:
>
> --- linux.orig/mm/oom_kill.c	2015-09-18 11:58:52.963946782 -0500
> +++ linux/mm/oom_kill.c	2015-09-18 11:59:42.010684778 -0500
> @@ -264,10 +264,9 @@ enum oom_scan_t oom_scan_process_thread(
>  	 * This task already has access to memory reserves and is being killed.
>  	 * Don't allow any other task to have access to the reserves.
>  	 */
> -	if (test_tsk_thread_flag(task, TIF_MEMDIE)) {
> -		if (oc->order != -1)
> -			return OOM_SCAN_ABORT;
> -	}
> +	if (test_tsk_thread_flag(task, TIF_MEMDIE))
> +		return OOM_SCAN_CONTINUE;
> +

Well, I can't really comment. Hopefully we will see more comments from
those who understand oom-killer.

But I still think this is not enough, and we need some (configurable?)
timeout before we pick another victim...


And btw. Yes, this is a bit off-topic, but I think another change make
sense too. We should report the fact we are going to kill another task
because the previous victim refuse to die, and print its stack trace.

Oleg.