From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55242) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VjRMU-0005a4-AA for qemu-devel@nongnu.org; Thu, 21 Nov 2013 05:19:53 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VjRMP-0005xD-A3 for qemu-devel@nongnu.org; Thu, 21 Nov 2013 05:19:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:3525) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VjRMP-0005wy-1X for qemu-devel@nongnu.org; Thu, 21 Nov 2013 05:19:45 -0500 Date: Thu, 21 Nov 2013 10:19:34 +0000 From: "Daniel P. Berrange" Message-ID: <20131121101934.GA9135@redhat.com> References: <1385025100-3191-1-git-send-email-lilei@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1385025100-3191-1-git-send-email-lilei@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH 0/17 v3] Localhost migration with side channel for ram Reply-To: "Daniel P. Berrange" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Lei Li Cc: aarcange@redhat.com, quintela@redhat.com, mdroth@linux.vnet.ibm.com, mrhines@linux.vnet.ibm.com, qemu-devel@nongnu.org, aliguori@amazon.com, lagarcia@br.ibm.com, pbonzini@redhat.com, rcj@linux.vnet.ibm.com On Thu, Nov 21, 2013 at 05:11:23PM +0800, Lei Li wrote: > This patch series tries to introduce a mechanism using side > channel pipe for RAM via SCM_RIGHTS with unix domain socket > protocol migration. > > This side channel is used for the page flipping by vmsplice, > which is the internal mechanism for localhost migration that > we are trying to add to QEMU. The backgroud info and previous > patch series for reference, > > Localhost migration > http://lists.nongnu.org/archive/html/qemu-devel/2013-08/msg02916.html > > migration: Introduce side channel for RAM > http://lists.gnu.org/archive/html/qemu-devel/2013-09/msg04043.html > > I have picked patches from the localhost migration series and rebased > it on the series of side channel, now it is a complete series that > passed the basic test. > > Please let me know if there is anything needs to be fixed or improved. > Your suggestions and comments are very welcome, and thanks to Paolo > for his continued review and useful suggestions. In discussions about supporting this for libvirt, we were told that when this localhost migration fails, you cannot re-start the guest on the original source QEMU. If this is true, this implementation is not satisfactory IMHO. One of the main motivations of this feature is to allow for in-place live upgrades of QEMU binaries, for people who can't tolerate the downtime of restarting their guests, and whom don't have a spare host to migrate them to. If people are using this because they can't tolerate any downtime of the guest, then we need to be able to fully deal with failure to complete migration by switching back to the original QEMU process, as we can do with normal non-localhost migration. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|