Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755904Ab1D0Bh7 (ORCPT ); Tue, 26 Apr 2011 21:37:59 -0400 Received: from mail-wy0-f174.google.com ([74.125.82.174]:41664 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751212Ab1D0Bh6 (ORCPT ); Tue, 26 Apr 2011 21:37:58 -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=QYBN0teYrvEJxJaMpRltq1UvJlEnB47/aT2QT0OdgJp2eb7i80KnPalyW8CWx0/Mov Oal1/ZUi4GgiRPPmZPDnB7oxi/DqLkzkhzCEo6qVppk9ISKF1/7SvWa2dw+lU2GmHlva QNQPxuj9QAwSyRc87Vknq5cH7ZkfskqqqQs8w= MIME-Version: 1.0 In-Reply-To: References: <20110426085953.GA12389@darkstar> Date: Wed, 27 Apr 2011 09:37:57 +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: 2072 Lines: 57 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. > 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 -- 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/