Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755901Ab1CVXVR (ORCPT ); Tue, 22 Mar 2011 19:21:17 -0400 Received: from mail-iy0-f174.google.com ([209.85.210.174]:42660 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755838Ab1CVXVO convert rfc822-to-8bit (ORCPT ); Tue, 22 Mar 2011 19:21:14 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=nolxyZgy+pBqXnRMQyugFNluSZgkdxg1JdIvpMLuvVFerzfjubAZG7QKRjRfk4tc+W yv22gc+/v8tcH3wgVxKocX9malZEvKWt8cUd5AJ9/dzMeAUy8Vzp9QReTbRuZksPdvbd +KapxfUazc2M4vpyk80wz80z9QLTaLqcSkkPE= 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 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 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1788 Lines: 42 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. > >  ------------------------------------------------------------------------------ >  Task                  |   Runtime ms  | Average delay ms | Maximum delay ms | >  ------------------------------------------------------------------------------ >  python:1754           |      0.197 ms | avg: 1731.727 ms | max: 3433.805 ms | >  python:1843           |      0.489 ms | avg: 1707.433 ms | max: 3622.955 ms | >  python:1715           |      0.220 ms | avg: 1707.125 ms | max: 3623.246 ms | >  python:1818           |      2.127 ms | avg: 1527.331 ms | max: 3622.553 ms | >  ... >  ... > > 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. -- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/