Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756047Ab1D0Bsv (ORCPT ); Tue, 26 Apr 2011 21:48:51 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:64249 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755744Ab1D0Bsu (ORCPT ); Tue, 26 Apr 2011 21:48:50 -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=wHKZ0cADt6aupprmgP9AOzHefkSzVR2GoPJFoLqOLYLMDyKNO6piHvAD11gmjtaDay a31nEdw7aGdhChMr9vTjy1L5RXhMzlEWfxMdCyJXiAnDczw5dhWbMvDHr7j0KD92YQes rBi/n9EjhOBkFqYRh29xk5xWkkchvst666ZLs= MIME-Version: 1.0 In-Reply-To: References: <20110426085953.GA12389@darkstar> Date: Wed, 27 Apr 2011 09:48:48 +0800 Message-ID: Subject: Re: [PATCH v2] virtio_balloon: disable oom killer when fill balloon From: Dave Young To: Minchan Kim Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, kosaki.motohiro@jp.fujitsu.com, 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: 2337 Lines: 69 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. > >> And as I previous said, we have to solve oom_killer_disabled issue in >> do_try_to_free_pages. >> >> Thanks, Dave. >> -- >> Kind regards, >> Minchan Kim >> > > > > -- > Regards > dave > -- 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/