From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id BCC558D0040 for ; Tue, 22 Mar 2011 19:21:15 -0400 (EDT) Received: by iyf13 with SMTP id 13so10917685iyf.14 for ; Tue, 22 Mar 2011 16:21:13 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110322200759.B067.A69D9226@jp.fujitsu.com> References: <20110315153801.3526.A69D9226@jp.fujitsu.com> <20110322194721.B05E.A69D9226@jp.fujitsu.com> <20110322200759.B067.A69D9226@jp.fujitsu.com> Date: Wed, 23 Mar 2011 08:21:12 +0900 Message-ID: Subject: Re: [PATCH 3/5] oom: create oom autogroup From: Minchan Kim Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: linux-kernel@vger.kernel.org, Andrew Morton , David Rientjes , Linus Torvalds , Rik van Riel , Oleg Nesterov , linux-mm , Andrey Vagin , Hugh Dickins , KAMEZAWA Hiroyuki , Mike Galbraith On Tue, Mar 22, 2011 at 8:08 PM, KOSAKI Motohiro wrote: > When plenty processes (eg fork bomb) are running, the TIF_MEMDIE task > never exit, at least, human feel it's never. therefore kernel become > hang-up. > > "perf sched" tell us a hint. > > =C2=A0-------------------------------------------------------------------= ----------- > =C2=A0Task =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= | =C2=A0 Runtime ms =C2=A0| Average delay ms | Maximum delay ms | > =C2=A0-------------------------------------------------------------------= ----------- > =C2=A0python:1754 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 | =C2=A0 =C2=A0 =C2= =A00.197 ms | avg: 1731.727 ms | max: 3433.805 ms | > =C2=A0python:1843 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 | =C2=A0 =C2=A0 =C2= =A00.489 ms | avg: 1707.433 ms | max: 3622.955 ms | > =C2=A0python:1715 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 | =C2=A0 =C2=A0 =C2= =A00.220 ms | avg: 1707.125 ms | max: 3623.246 ms | > =C2=A0python:1818 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 | =C2=A0 =C2=A0 =C2= =A02.127 ms | avg: 1527.331 ms | max: 3622.553 ms | > =C2=A0... > =C2=A0... > > Processes flood makes crazy scheduler delay. and then the victim process > can't run enough. Grr. Should we do? > > Fortunately, we already have anti process flood framework, autogroup! > This patch reuse this framework and avoid kernel live lock. That's cool idea but I have a concern. You remove boosting priority in [2/5] and move victim tasks into autogroup. If I understand autogroup right, victim process and threads in the process take less schedule chance than now. Could it make unnecessary killing of other tasks? I am not sure. Just out of curiosity. Thanks for nice work, Kosaki. --=20 Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org