From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33221) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZmbcG-0002o7-W5 for qemu-devel@nongnu.org; Thu, 15 Oct 2015 02:02:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZmbcD-0006lu-3O for qemu-devel@nongnu.org; Thu, 15 Oct 2015 02:02:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48701) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZmbcC-0006lq-Ty for qemu-devel@nongnu.org; Thu, 15 Oct 2015 02:02:13 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (Postfix) with ESMTPS id 77CA68C1D5 for ; Thu, 15 Oct 2015 06:02:12 +0000 (UTC) Date: Thu, 15 Oct 2015 11:31:48 +0530 From: Amit Shah Message-ID: <20151015060148.GC31081@grmbl.mre> References: <18ab6aea9a24a21bf2686a2ab220434951d53dc0.1444824439.git.amit.shah@redhat.com> <87r3kxpovo.fsf@neno.neno> <20151014165126-mutt-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151014165126-mutt-send-email-mst@redhat.com> Subject: Re: [Qemu-devel] [PATCH 1/1] migration: announce VM's new home just before VM is runnable List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Jason Wang , qemu list , "Dr. David Alan Gilbert" , Juan Quintela On (Wed) 14 Oct 2015 [17:12:44], Michael S. Tsirkin wrote: > On Wed, Oct 14, 2015 at 03:21:15PM +0200, Juan Quintela wrote: > > Amit Shah wrote: > > > We were announcing the dest host's IP as our new IP a bit too soon -- if > > > there were errors detected after this announcement was done, the > > > migration is failed and the VM could continue running on the src host -- > > > causing problems later. > > > > > > Move around the qemu_announce_self() call so it's done just before the > > > VM is runnable. > > > > > > Signed-off-by: Amit Shah > > > > Reviewed-by: Juan Quintela > > > > applied. > > > > I have the same question than Dave, but also agree that this is a > > movement in the right direction. > > > > Why it is not only needed when we do a vm_start()? > > It's a complex question. We don't want to do this on each > vmstop/vmcont. But maybe we want to, on the 1st vmstart after > qemu is started. Why? When a guest starts, it will issue ARP requests and everything will just work. We need this announce_self only to tell the switches that the MAC belonging to the guest's IP has changed.. Amit