From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51165) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eltcG-0003Lg-Lh for qemu-devel@nongnu.org; Wed, 14 Feb 2018 04:44:41 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eltcC-0001E1-Oh for qemu-devel@nongnu.org; Wed, 14 Feb 2018 04:44:40 -0500 Received: from 2.mo2.mail-out.ovh.net ([188.165.53.149]:36159) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eltcC-0001Dk-Gc for qemu-devel@nongnu.org; Wed, 14 Feb 2018 04:44:36 -0500 Received: from player157.ha.ovh.net (gw6.ovh.net [213.251.189.206]) by mo2.mail-out.ovh.net (Postfix) with ESMTP id 5BF9511BD3B for ; Wed, 14 Feb 2018 10:44:34 +0100 (CET) Date: Wed, 14 Feb 2018 10:44:31 +0100 From: Greg Kurz Message-ID: <20180214104431.294a5280@bahia.lan> In-Reply-To: <20180207155500.GO2665@work-vm> References: <151801810352.29167.4832480228518630626.stgit@bahia.lan> <20180207155500.GO2665@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] migration: improve documentation of postcopy-ram List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: qemu-devel@nongnu.org, Juan Quintela On Wed, 7 Feb 2018 15:55:01 +0000 "Dr. David Alan Gilbert" wrote: > * Greg Kurz (groug@kaod.org) wrote: > > This capability must have the same value on both source and destination, > > otherwise migration fails (commit 875fcd013ab6 "migration: incoming > > postcopy advise sanity checks"). > > > > Let's write it down in various places where postcopy-ram is documented. > > > > Signed-off-by: Greg Kurz > > Thanks, > > Reviewed-by: Dr. David Alan Gilbert > Who should pick this up ? > > --- > > docs/devel/migration.rst | 4 ++-- > > hmp-commands.hx | 3 ++- > > qapi/migration.json | 10 ++++++---- > > 3 files changed, 10 insertions(+), 7 deletions(-) > > > > diff --git a/docs/devel/migration.rst b/docs/devel/migration.rst > > index bf97080dac2f..9d1b7657f0cf 100644 > > --- a/docs/devel/migration.rst > > +++ b/docs/devel/migration.rst > > @@ -387,8 +387,8 @@ doesn't finish in a given time the switch is made to postcopy. > > Enabling postcopy > > ----------------- > > > > -To enable postcopy, issue this command on the monitor prior to the > > -start of migration: > > +To enable postcopy, issue this command on the monitor (both source and > > +destination) prior to the start of migration: > > > > ``migrate_set_capability postcopy-ram on`` > > > > diff --git a/hmp-commands.hx b/hmp-commands.hx > > index 15620c94d3fc..d26eb4119b9d 100644 > > --- a/hmp-commands.hx > > +++ b/hmp-commands.hx > > @@ -1041,7 +1041,8 @@ ETEXI > > .params = "", > > .help = "Followup to a migration command to switch the migration" > > " to postcopy mode. The postcopy-ram capability must " > > - "be set before the original migration command.", > > + "be set on both source and destination before the " > > + "original migration command .", > > .cmd = hmp_migrate_start_postcopy, > > }, > > > > diff --git a/qapi/migration.json b/qapi/migration.json > > index 4cd3d1315884..7f465a1902ce 100644 > > --- a/qapi/migration.json > > +++ b/qapi/migration.json > > @@ -327,8 +327,10 @@ > > # to speed up convergence of RAM migration. (since 1.6) > > # > > # @postcopy-ram: Start executing on the migration target before all of RAM has > > -# been migrated, pulling the remaining pages along as needed. NOTE: If > > -# the migration fails during postcopy the VM will fail. (since 2.6) > > +# been migrated, pulling the remaining pages along as needed. The > > +# capacity must have the same setting on both source and target > > +# or migration will not even start. NOTE: If the migration fails during > > +# postcopy the VM will fail. (since 2.6) > > # > > # @x-colo: If enabled, migration will never end, and the state of the VM on the > > # primary side will be migrated continuously to the VM on secondary > > @@ -742,8 +744,8 @@ > > # @migrate-start-postcopy: > > # > > # Followup to a migration command to switch the migration to postcopy mode. > > -# The postcopy-ram capability must be set before the original migration > > -# command. > > +# The postcopy-ram capability must be set on both source and destination > > +# before the original migration command. > > # > > # Since: 2.5 > > # > > > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK >