From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52811) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vksmg-000561-IW for qemu-devel@nongnu.org; Mon, 25 Nov 2013 04:48:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VksmY-0005Jv-CE for qemu-devel@nongnu.org; Mon, 25 Nov 2013 04:48:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:22192) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VksmY-0005HB-2N for qemu-devel@nongnu.org; Mon, 25 Nov 2013 04:48:42 -0500 Message-ID: <52931CED.9090103@redhat.com> Date: Mon, 25 Nov 2013 10:48:29 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1385025100-3191-1-git-send-email-lilei@linux.vnet.ibm.com> <20131121101934.GA9135@redhat.com> <528F4001.3050600@linux.vnet.ibm.com> <528F41BD.1050007@redhat.com> <5292FC60.6080906@linux.vnet.ibm.com> In-Reply-To: <5292FC60.6080906@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 0/17 v3] Localhost migration with side channel for ram List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Lei Li Cc: Andrea Arcangeli , quintela@redhat.com, mdroth@linux.vnet.ibm.com, mrhines@linux.vnet.ibm.com, qemu-devel@nongnu.org, aliguori@amazon.com, lagarcia@br.ibm.com, rcj@linux.vnet.ibm.com Il 25/11/2013 08:29, Lei Li ha scritto: > > > In this case, if the migration would fail just because the misconfiguration > of device state on destination, in the meantime the outgoing migration has > no aware of this failure, I think it should add such handling (like synchronize > of the device state list in incoming side?) to the current migration protocol > as it is kind of missing... It can not just rely on the resume of source > guest for such failure... or maybe it should be handled in management > app to force the configuration right? It is already handled by libvirt, indeed. Basically, "-incoming" without "-S" is a broken option because of the missing handshake at the end of migration. With "-S" something else (either a human or a program) can check that everything went well and choose whether to restart the source or the destination. >> Postcopy would fix this (assuming the postcopy phase is reliable) by >> migrating device data before any page flipping occurs. > > Are you suggesting that page flipping should be coupled with the postcopy > migration for live upgrade of QEMU as your comments in the previous > version? In order to make live upgrade reliable, it should. Paolo