From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id C4FB09000C1 for ; Tue, 26 Apr 2011 22:06:49 -0400 (EDT) Received: from m4.gw.fujitsu.co.jp (unknown [10.0.50.74]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 6DE313EE0C1 for ; Wed, 27 Apr 2011 11:06:46 +0900 (JST) Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 5466745DE50 for ; Wed, 27 Apr 2011 11:06:46 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 3DD2A45DE4D for ; Wed, 27 Apr 2011 11:06:46 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 27523E78003 for ; Wed, 27 Apr 2011 11:06:46 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.240.81.134]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id DB6C1E78002 for ; Wed, 27 Apr 2011 11:06:45 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH v2] virtio_balloon: disable oom killer when fill balloon In-Reply-To: References: Message-Id: <20110427110838.D178.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Date: Wed, 27 Apr 2011 11:06:45 +0900 (JST) Sender: owner-linux-mm@kvack.org List-ID: To: Dave Young Cc: kosaki.motohiro@jp.fujitsu.com, Minchan Kim , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm > On Wed, Apr 27, 2011 at 9:37 AM, Dave Young wrote: > > On Wed, Apr 27, 2011 at 7:33 AM, Minchan Kim wrote: > >> On Tue, Apr 26, 2011 at 6:39 PM, Dave Young wrote: > >>> On Tue, Apr 26, 2011 at 5:28 PM, Minchan Kim wrote: > >>>> Please resend this with [2/2] to linux-mm. > >>>> > >>>> On Tue, Apr 26, 2011 at 5:59 PM, Dave Young wrote: > >>>>> When memory pressure is high, virtio ballooning will probably cause oom killing. > >>>>> Even if alloc_page with GFP_NORETRY itself does not directly trigger oom it > >>>>> will make memory becoming low then memory alloc of other processes will trigger > >>>>> oom killing. It is not desired behaviour. > >>>> > >>>> I can't understand why it is undesirable. > >>>> Why do we have to handle it specially? > >>>> > >>> > >>> Suppose user run some random memory hogging process while ballooning > >>> it will be undesirable. > >> > >> > >> In VM POV, kvm and random memory hogging processes are customers. > >> If we handle ballooning specially with disable OOM, what happens other > >> processes requires memory at same time? Should they wait for balloon > >> driver to release memory? > >> > >> I don't know your point. Sorry. > >> Could you explain your scenario in detail for justify your idea? > > > > What you said make sense I understand what you said now. Lets ignore > > my above argue and see what I'm actually doing. > > > > I'm hacking with balloon driver to fit to short the vm migration time. > > > > while migrating host tell guest to balloon as much memory as it can, then start > > migrate, just skip the ballooned pages, after migration done tell > > guest to release the memory. > > > > In migration case oom is not I want to see and disable oom will be good. > > BTW, if oom_killer_disabled is really not recommended to use I can > switch back to oom_notifier way. Could you please explain why you dislike oom_notifier and what problem you faced? I haven't understand why oom_notifier is bad. probably my less knowledge of balloon is a reason. -- 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