From patchwork Mon Jan 24 09:02:38 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marcelo Tosatti X-Patchwork-Id: 80115 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 528E9B7120 for ; Mon, 24 Jan 2011 20:36:02 +1100 (EST) Received: from localhost ([127.0.0.1]:34024 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PhIq6-0003AZ-Po for incoming@patchwork.ozlabs.org; Mon, 24 Jan 2011 04:35:58 -0500 Received: from [140.186.70.92] (port=38031 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PhIMU-0008NZ-Nq for qemu-devel@nongnu.org; Mon, 24 Jan 2011 04:05:30 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PhIMP-0007FO-RQ for qemu-devel@nongnu.org; Mon, 24 Jan 2011 04:05:22 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50749) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PhIMP-0007Em-K8 for qemu-devel@nongnu.org; Mon, 24 Jan 2011 04:05:17 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id p0O95FBC014540 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 24 Jan 2011 04:05:16 -0500 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id p0O95F5S018143; Mon, 24 Jan 2011 04:05:15 -0500 Received: from amt.cnet (vpn2-9-29.ams2.redhat.com [10.36.9.29]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id p0O95B2B008811; Mon, 24 Jan 2011 04:05:14 -0500 Received: from amt.cnet (localhost.localdomain [127.0.0.1]) by amt.cnet (Postfix) with ESMTP id 50303652160; Mon, 24 Jan 2011 07:04:48 -0200 (BRST) Received: (from marcelo@localhost) by amt.cnet (8.14.4/8.14.4/Submit) id p0O94jQB028425; Mon, 24 Jan 2011 07:04:45 -0200 From: Marcelo Tosatti To: Anthony Liguori Date: Mon, 24 Jan 2011 07:02:38 -0200 Message-Id: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. Cc: Jan Kiszka , Marcelo Tosatti , qemu-devel@nongnu.org, kvm@vger.kernel.org Subject: [Qemu-devel] [PATCH 29/31] kvm: Do not use qemu_fair_mutex X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Jan Kiszka The imbalance in the hold time of qemu_global_mutex only exists in TCG mode. In contrast to TCG VCPUs, KVM drops the global lock during guest execution. We already avoid touching the fairness lock from the IO-thread in KVM mode, so also stop using it from the VCPU threads. Signed-off-by: Jan Kiszka Signed-off-by: Marcelo Tosatti --- cpus.c | 2 -- 1 files changed, 0 insertions(+), 2 deletions(-) diff --git a/cpus.c b/cpus.c index 0309189..4c9928e 100644 --- a/cpus.c +++ b/cpus.c @@ -735,9 +735,7 @@ static sigset_t block_io_signals(void) void qemu_mutex_lock_iothread(void) { if (kvm_enabled()) { - qemu_mutex_lock(&qemu_fair_mutex); qemu_mutex_lock(&qemu_global_mutex); - qemu_mutex_unlock(&qemu_fair_mutex); } else { qemu_mutex_lock(&qemu_fair_mutex); if (qemu_mutex_trylock(&qemu_global_mutex)) {