From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39595) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V3n5f-0005Wg-Ou for qemu-devel@nongnu.org; Mon, 29 Jul 2013 09:02:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V3n5Z-000127-98 for qemu-devel@nongnu.org; Mon, 29 Jul 2013 09:02:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:6593) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V3n5Z-000123-1q for qemu-devel@nongnu.org; Mon, 29 Jul 2013 09:02:13 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r6TD2ChG008982 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 29 Jul 2013 09:02:12 -0400 From: Stefan Hajnoczi Date: Mon, 29 Jul 2013 15:01:57 +0200 Message-Id: <1375102920-18817-2-git-send-email-stefanha@redhat.com> In-Reply-To: <1375102920-18817-1-git-send-email-stefanha@redhat.com> References: <1375102920-18817-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH v3 1/4] migration: notify migration state before starting thread List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Stefan Hajnoczi , Juan Quintela The migration thread runs outside the QEMU global mutex when possible. Therefore we must notify migration state change *before* starting the migration thread. This allows registered listeners to act before live migration iterations begin. Therefore they can get into a state that allows for live migration. When the migration thread starts everything will be ready. Without this patch there is a race condition during migration setup, depending on whether the migration thread has already transitioned from SETUP to ACTIVE state. Acked-by: Paolo Bonzini Signed-off-by: Stefan Hajnoczi --- migration.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/migration.c b/migration.c index e12e784..a5ed26b 100644 --- a/migration.c +++ b/migration.c @@ -658,7 +658,9 @@ void migrate_fd_connect(MigrationState *s) qemu_file_set_rate_limit(s->file, s->bandwidth_limit / XFER_LIMIT_RATIO); + /* Notify before starting migration thread */ + notifier_list_notify(&migration_state_notifiers, s); + qemu_thread_create(&s->thread, migration_thread, s, QEMU_THREAD_JOINABLE); - notifier_list_notify(&migration_state_notifiers, s); } -- 1.8.1.4