From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54993) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cTS9N-0006kM-4i for qemu-devel@nongnu.org; Tue, 17 Jan 2017 06:42:06 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cTS9K-00029e-1w for qemu-devel@nongnu.org; Tue, 17 Jan 2017 06:42:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37528) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cTS9J-00029A-RV for qemu-devel@nongnu.org; Tue, 17 Jan 2017 06:42:01 -0500 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BAACEC056790 for ; Tue, 17 Jan 2017 11:42:01 +0000 (UTC) Date: Tue, 17 Jan 2017 11:41:57 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20170117114156.GE2053@work-vm> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [PATCH] migration: expose qemu_announce_self() via qmp List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Germano Veit Michel Cc: qemu-devel@nongnu.org, amit.shah@redhat.com, quintela@redhat.com * Germano Veit Michel (germano@redhat.com) wrote: > qemu_announce_self() is triggered by qemu at the end of migrations > to update the network regarding the path to the guest l2addr. > > however it is also useful when there is a network change such as > an active bond slave swap. Essentially, it's the same as a migration > from a network perspective - the guest moves to a different point > in the network topology. > > this exposes the function via qmp. > > Signed-off-by: Germano Veit Michel Hi Germano, I think there are a couple of problems which mean it's not quite this simple. a) The 'count' variable in qemu_announce_self_once is static initialised; so I think qemu will only ever run the announce series once; so it would do it after migrate, but then I think if you did a qemu_announce_self again I think it would send one packet and then not repeat it. Similarly if you called qemu_announce_self from qmp twice I'm not sure the 2nd time would only send the one packet. b) The static *time in qemu_announce_self means I'm worried about what happens if someone was to call qmp_announce_self before the previous round of qmp_announce_self had finished; I think you'd end up with 2 timers racing on one pointer. Dave > --- > migration/savevm.c | 5 +++++ > qapi-schema.json | 18 ++++++++++++++++++ > 2 files changed, 23 insertions(+) > > diff --git a/migration/savevm.c b/migration/savevm.c > index f9c06e9..7a817dc 100644 > --- a/migration/savevm.c > +++ b/migration/savevm.c > @@ -143,6 +143,11 @@ void qemu_announce_self(void) > qemu_announce_self_once(&timer); > } > > +void qmp_announce_self(Error **errp) > +{ > + qemu_announce_self(); > +} > + > /***********************************************************/ > /* savevm/loadvm support */ > > diff --git a/qapi-schema.json b/qapi-schema.json > index ce20f16..6854266 100644 > --- a/qapi-schema.json > +++ b/qapi-schema.json > @@ -4786,3 +4786,21 @@ > # Since: 2.7 > ## > { 'command': 'query-hotpluggable-cpus', 'returns': ['HotpluggableCPU'] } > + > +## > +# @announce-self: > +# > +# Trigger generation of broadcast RARP frames to update network switches. > +# This can be useful when network bonds fail-over the active slave. > +# > +# Arguments: None. > +# > +# Example: > +# > +# -> { "execute": "announce-self" } > +# <- { "return": {} } > +# > +# Since: 2.9 > +## > +{ 'command': 'announce-self' } > + > -- > 2.9.3 -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK