From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:45848) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h2fjE-0005cc-E4 for qemu-devel@nongnu.org; Sat, 09 Mar 2019 12:25:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1h2fjC-0006m7-9u for qemu-devel@nongnu.org; Sat, 09 Mar 2019 12:25:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:51274) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1h2fjA-0006kN-8y for qemu-devel@nongnu.org; Sat, 09 Mar 2019 12:25:40 -0500 From: Markus Armbruster References: <20190305181602.9051-1-dgilbert@redhat.com> <20190305181602.9051-6-dgilbert@redhat.com> Date: Sat, 09 Mar 2019 18:25:33 +0100 In-Reply-To: <20190305181602.9051-6-dgilbert@redhat.com> (David Alan Gilbert's message of "Tue, 5 Mar 2019 18:15:46 +0000") Message-ID: <87zhq40xki.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PULL 05/21] migration: Introduce ignore-shared capability List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert (git)" Cc: qemu-devel@nongnu.org, quintela@redhat.com, peterx@redhat.com, marcel.apfelbaum@gmail.com, wei.w.wang@intel.com, yury-kotov@yandex-team.ru, chen.zhang@intel.com "Dr. David Alan Gilbert (git)" writes: > From: Yury Kotov > > We want to use local migration to update QEMU for running guests. > In this case we don't need to migrate shared (file backed) RAM. > So, add a capability to ignore such blocks during live migration. > > Signed-off-by: Yury Kotov > Message-Id: <20190215174548.2630-3-yury-kotov@yandex-team.ru> > Reviewed-by: Dr. David Alan Gilbert > Signed-off-by: Dr. David Alan Gilbert > --- [...] > diff --git a/qapi/migration.json b/qapi/migration.json > index 1fd7bbea9b..eab87340b2 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -409,13 +409,16 @@ > # devices (and thus take locks) immediately at the end of migration. > # (since 3.0) > # > +# @x-ignore-shared: If enabled, QEMU will not migrate shared memory (since 4.0) What exactly is considered "shared memory"? Specifically: say you have an ivshmem-plain device. Is its shared memory migrated? No objection to the pull request; if documentation improvements are necessary, we can do them in a follow-up patch. > +# > # Since: 1.2 > ## > { 'enum': 'MigrationCapability', > 'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks', > 'compress', 'events', 'postcopy-ram', 'x-colo', 'release-ram', > 'block', 'return-path', 'pause-before-switchover', 'x-multifd', > - 'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate' ] } > + 'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate', > + 'x-ignore-shared' ] } > > ## > # @MigrationCapabilityStatus: