From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47282) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ejS3u-0003la-3S for qemu-devel@nongnu.org; Wed, 07 Feb 2018 10:55:10 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ejS3s-0006hg-Ed for qemu-devel@nongnu.org; Wed, 07 Feb 2018 10:55:06 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:57778 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ejS3s-0006hL-8v for qemu-devel@nongnu.org; Wed, 07 Feb 2018 10:55:04 -0500 Date: Wed, 7 Feb 2018 15:55:01 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20180207155500.GO2665@work-vm> References: <151801810352.29167.4832480228518630626.stgit@bahia.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <151801810352.29167.4832480228518630626.stgit@bahia.lan> Subject: Re: [Qemu-devel] [PATCH] migration: improve documentation of postcopy-ram List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Greg Kurz Cc: qemu-devel@nongnu.org, Juan Quintela * 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 > --- > 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