From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [RFC Design Doc]Speed up live migration by skipping free pages Date: Thu, 24 Mar 2016 16:18:29 +0100 Message-ID: <56F40545.3020503@redhat.com> References: <1458632629-4649-1-git-send-email-liang.z.li@intel.com> <20160322101116.GA9532@redhat.com> <20160323155325-mutt-send-email-mst@redhat.com> <20160324094846.GA17006@redhat.com> <20160324122627-mutt-send-email-mst@redhat.com> <20160324164006-mutt-send-email-mst@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: "qemu-devel@nongnu.org" , "kvm@vger.kernel.org" , "linux-kernel@vger.kenel.org" , "rth@twiddle.net" , "ehabkost@redhat.com" , "amit.shah@redhat.com" , "quintela@redhat.com" , "dgilbert@redhat.com" , "mohan_parthasarathy@hpe.com" , "jitendra.kolhe@hpe.com" , "simhan@hpe.com" , "rkagan@virtuozzo.com" , "riel@redhat.com" To: "Li, Liang Z" , "Michael S. Tsirkin" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:41533 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751322AbcCXPSg (ORCPT ); Thu, 24 Mar 2016 11:18:36 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 24/03/2016 16:16, Li, Liang Z wrote: > > There's no guarantee that there's a single 'hole' > > even on the PC, and we want balloon to be portable. > > As long as we know how many 'hole' and where the holes are. The mapping between ram_addr_t and GPA is completely internal to QEMU. Passing it to the guest is a layering violation. Paolo > we can filter out them. QEMU should have this kind of information. > I know my RFC patch passed an arch specific free page bitmap is not > a good idea. So in my design, I changed this by passing a loose free page > bitmap which contains the holes, and let QEMU to filter out the holes > according to some arch specific information. This can make balloon be portable. > From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34854) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aj722-0004TP-Je for qemu-devel@nongnu.org; Thu, 24 Mar 2016 11:18:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aj71w-0003o7-Eq for qemu-devel@nongnu.org; Thu, 24 Mar 2016 11:18:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:23086) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aj71w-0003nq-96 for qemu-devel@nongnu.org; Thu, 24 Mar 2016 11:18:36 -0400 References: <1458632629-4649-1-git-send-email-liang.z.li@intel.com> <20160322101116.GA9532@redhat.com> <20160323155325-mutt-send-email-mst@redhat.com> <20160324094846.GA17006@redhat.com> <20160324122627-mutt-send-email-mst@redhat.com> <20160324164006-mutt-send-email-mst@redhat.com> From: Paolo Bonzini Message-ID: <56F40545.3020503@redhat.com> Date: Thu, 24 Mar 2016 16:18:29 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC Design Doc]Speed up live migration by skipping free pages List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Li, Liang Z" , "Michael S. Tsirkin" Cc: "rkagan@virtuozzo.com" , "linux-kernel@vger.kenel.org" , "ehabkost@redhat.com" , "kvm@vger.kernel.org" , "quintela@redhat.com" , "simhan@hpe.com" , "qemu-devel@nongnu.org" , "dgilbert@redhat.com" , "jitendra.kolhe@hpe.com" , "mohan_parthasarathy@hpe.com" , "amit.shah@redhat.com" , "rth@twiddle.net" On 24/03/2016 16:16, Li, Liang Z wrote: > > There's no guarantee that there's a single 'hole' > > even on the PC, and we want balloon to be portable. > > As long as we know how many 'hole' and where the holes are. The mapping between ram_addr_t and GPA is completely internal to QEMU. Passing it to the guest is a layering violation. Paolo > we can filter out them. QEMU should have this kind of information. > I know my RFC patch passed an arch specific free page bitmap is not > a good idea. So in my design, I changed this by passing a loose free page > bitmap which contains the holes, and let QEMU to filter out the holes > according to some arch specific information. This can make balloon be portable. >