From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51508) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V3pUs-0006IO-5o for qemu-devel@nongnu.org; Mon, 29 Jul 2013 11:36:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V3pUm-0002bQ-4R for qemu-devel@nongnu.org; Mon, 29 Jul 2013 11:36:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:62993) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V3pUl-0002bL-SA for qemu-devel@nongnu.org; Mon, 29 Jul 2013 11:36:24 -0400 From: Stefan Hajnoczi Date: Mon, 29 Jul 2013 17:36:09 +0200 Message-Id: <1375112172-24863-4-git-send-email-stefanha@redhat.com> In-Reply-To: <1375112172-24863-1-git-send-email-stefanha@redhat.com> References: <1375112172-24863-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH 3/6] 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: Anthony Liguori , Stefan Hajnoczi 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 Reviewed-by: Kevin Wolf 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