From patchwork Mon Jul 29 15:36:09 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 262827 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id D8B922C00F3 for ; Tue, 30 Jul 2013 01:38:15 +1000 (EST) Received: from localhost ([::1]:46487 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V3pWW-0000Bs-K3 for incoming@patchwork.ozlabs.org; Mon, 29 Jul 2013 11:38:12 -0400 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 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r6TFaNFr016389 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 29 Jul 2013 11:36:23 -0400 Received: from localhost (ovpn-112-50.ams2.redhat.com [10.36.112.50]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id r6TFaMhb013892; Mon, 29 Jul 2013 11:36:22 -0400 From: Stefan Hajnoczi To: 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> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Anthony Liguori , Stefan Hajnoczi Subject: [Qemu-devel] [PATCH 3/6] migration: notify migration state before starting thread X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org 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); }