Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757817Ab1D0CWu (ORCPT ); Tue, 26 Apr 2011 22:22:50 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:63713 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756681Ab1D0CWZ (ORCPT ); Tue, 26 Apr 2011 22:22:25 -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; b=UgydGrdBXLTMdlOuZCB0BA/WmJ0W8NR7/dyqbgV1lZn7Tn9aw+0TE8iJfpxbofSdSJ o/Hca50I7a70sRWDqCHzoNY8ix4CdGwMug4C5WnCdNw9lP65BTQfEiwdbg6LK3k5bFN1 nvRRxLbW0YiI6tvIoypCV5xZlhJIJZYqBCSEk= MIME-Version: 1.0 In-Reply-To: <20110427110838.D178.A69D9226@jp.fujitsu.com> References: <20110427110838.D178.A69D9226@jp.fujitsu.com> Date: Wed, 27 Apr 2011 10:22:24 +0800 Message-ID: Subject: Re: [PATCH v2] virtio_balloon: disable oom killer when fill balloon From: Dave Young To: KOSAKI Motohiro Cc: Minchan Kim , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2727 Lines: 61 On Wed, Apr 27, 2011 at 10:06 AM, KOSAKI Motohiro wrote: >> 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. > Both is fine for me indeed, oom_killer_disable is more simple to use instead. I ever sent a oom_notifier patch last year and did not get much intention, I can refresh and resend it. -- Regards dave -- 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/