From patchwork Wed Apr 27 19:08:42 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 8962061 Return-Path: X-Original-To: patchwork-qemu-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id F0276BF29F for ; Wed, 27 Apr 2016 19:09:06 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5DCB6200E5 for ; Wed, 27 Apr 2016 19:09:06 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B2E4720260 for ; Wed, 27 Apr 2016 19:09:05 +0000 (UTC) Received: from localhost ([::1]:44832 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1avUpc-0000R5-TO for patchwork-qemu-devel@patchwork.kernel.org; Wed, 27 Apr 2016 15:09:04 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36550) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1avUpQ-0000ND-9l for qemu-devel@nongnu.org; Wed, 27 Apr 2016 15:08:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1avUpO-00029Y-5W for qemu-devel@nongnu.org; Wed, 27 Apr 2016 15:08:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38382) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1avUpO-00029S-05 for qemu-devel@nongnu.org; Wed, 27 Apr 2016 15:08:50 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (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 BAA426F672; Wed, 27 Apr 2016 19:08:49 +0000 (UTC) Received: from dgilbert-t530.redhat.com (ovpn-116-108.ams2.redhat.com [10.36.116.108]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u3RJ8khg027538; Wed, 27 Apr 2016 15:08:48 -0400 From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, quintela@redhat.com, amit.shah@redhat.com Date: Wed, 27 Apr 2016 20:08:42 +0100 Message-Id: <1461784125-578-2-git-send-email-dgilbert@redhat.com> In-Reply-To: <1461784125-578-1-git-send-email-dgilbert@redhat.com> References: <1461784125-578-1-git-send-email-dgilbert@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 1/4] Postcopy: Avoid 0 length discards X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: aarcange@redhat.com, den@openvz.org, marcel.a@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Spam-Status: No, score=-5.9 required=5.0 tests=BAYES_00,HK_NAME_DR, RCVD_IN_DNSWL_HI,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: "Dr. David Alan Gilbert" The discard code in migration/ram.c would send request for zero length discards in the case where no discards were needed. It doesn't appear to have had any bad effect. Signed-off-by: Dr. David Alan Gilbert --- migration/ram.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/migration/ram.c b/migration/ram.c index 3f05738..e96c2af 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -1557,7 +1557,9 @@ static int postcopy_send_discard_bm_ram(MigrationState *ms, } else { discard_length = zero - one; } - postcopy_discard_send_range(ms, pds, one, discard_length); + if (discard_length) { + postcopy_discard_send_range(ms, pds, one, discard_length); + } current = one + discard_length; } else { current = one;