From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53420) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZmLlE-0001vI-4a for qemu-devel@nongnu.org; Wed, 14 Oct 2015 09:06:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZmLl9-0007Fl-1P for qemu-devel@nongnu.org; Wed, 14 Oct 2015 09:06:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54655) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZmLl8-0007FE-Sm for qemu-devel@nongnu.org; Wed, 14 Oct 2015 09:06:22 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (Postfix) with ESMTPS id 690F7319B0D for ; Wed, 14 Oct 2015 13:06:22 +0000 (UTC) Date: Wed, 14 Oct 2015 18:36:07 +0530 From: Amit Shah Message-ID: <20151014130607.GB31081@grmbl.mre> References: <18ab6aea9a24a21bf2686a2ab220434951d53dc0.1444824439.git.amit.shah@redhat.com> <20151014123829.GC2571@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151014123829.GC2571@work-vm> 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: "Dr. David Alan Gilbert" Cc: Jason Wang , "Michael S. Tsirkin" , qemu list , Juan Quintela On (Wed) 14 Oct 2015 [13:38:30], Dr. David Alan Gilbert wrote: > * Amit Shah (amit.shah@redhat.com) 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 > > --- > > migration/migration.c | 7 ++++++- > > 1 file changed, 6 insertions(+), 1 deletion(-) > > > > diff --git a/migration/migration.c b/migration/migration.c > > index b7de9b7..ca21ba8 100644 > > --- a/migration/migration.c > > +++ b/migration/migration.c > > @@ -295,7 +295,6 @@ static void process_incoming_migration_co(void *opaque) > > exit(EXIT_FAILURE); > > } > > migrate_generate_event(MIGRATION_STATUS_COMPLETED); > > - qemu_announce_self(); > > > > /* Make sure all file formats flush their mutable metadata */ > > bdrv_invalidate_cache_all(&local_err); > > @@ -305,6 +304,12 @@ static void process_incoming_migration_co(void *opaque) > > exit(EXIT_FAILURE); > > } > > > > + /* > > + * This must happen after all error conditions are dealt with and > > + * we're sure the VM is going to be running on this host. > > + */ > > + qemu_announce_self(); > > + > > OK, so that's certainly better than it was before; but should be even > further down? Should we do an announce-self at all if we are not > going to do the vm_start? Assumption is that if migration has succeeded, the VM will be started on this host. The VM is paused only because it was in paused state before the migration started -- due to an IO error, due to non-live migration -- so IMO this actually is the right place for that. Amit