Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932534AbcDSP0y (ORCPT ); Tue, 19 Apr 2016 11:26:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40373 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932106AbcDSP0x (ORCPT ); Tue, 19 Apr 2016 11:26:53 -0400 Message-ID: <1461079592.3200.9.camel@redhat.com> Subject: Re: [PATCH kernel 1/2] mm: add the related functions to build the free page bitmap From: Rik van Riel To: "Li, Liang Z" , "mst@redhat.com" , "viro@zeniv.linux.org.uk" , "linux-kernel@vger.kernel.org" , "quintela@redhat.com" , "amit.shah@redhat.com" , "pbonzini@redhat.com" , "dgilbert@redhat.com" Cc: "linux-mm@kvack.org" , "kvm@vger.kernel.org" , "qemu-devel@nongnu.org" , "agraf@suse.de" , "borntraeger@de.ibm.com" Date: Tue, 19 Apr 2016 11:26:32 -0400 In-Reply-To: References: <1461076474-3864-1-git-send-email-liang.z.li@intel.com> <1461076474-3864-2-git-send-email-liang.z.li@intel.com> <1461077659.3200.8.camel@redhat.com> Organization: Red Hat, Inc. Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Tue, 19 Apr 2016 15:26:52 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 799 Lines: 24 On Tue, 2016-04-19 at 15:02 +0000, Li, Liang Z wrote: > > > > On Tue, 2016-04-19 at 22:34 +0800, Liang Li wrote: > > > > > > The free page bitmap will be sent to QEMU through virtio > > > interface and > > > used for live migration optimization. > > > Drop the cache before building the free page bitmap can get more > > > free > > > pages. Whether dropping the cache is decided by user. > > > > > How do you prevent the guest from using those recently-freed pages > > for > > something else, between when you build the bitmap and the live > > migration > > completes? > Because the dirty page logging is enabled before building the bitmap, > there is no need > to prevent the guest from using the recently-freed pages ... Fair enough. It would be good to have that mentioned in the changelog.