From patchwork Fri Aug 30 04:29:18 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 2851792 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 73E56C0AB5 for ; Fri, 30 Aug 2013 04:43:37 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id ACA96203E6 for ; Fri, 30 Aug 2013 04:43:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D7C3C2039A for ; Fri, 30 Aug 2013 04:43:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755951Ab3H3Elb (ORCPT ); Fri, 30 Aug 2013 00:41:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48947 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755435Ab3H3ElM (ORCPT ); Fri, 30 Aug 2013 00:41:12 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r7U4fBua009672 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 30 Aug 2013 00:41:11 -0400 Received: from amd-6168-8-1.englab.nay.redhat.com (amd-6168-8-1.englab.nay.redhat.com [10.66.104.52]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r7U4evxw013964; Fri, 30 Aug 2013 00:41:06 -0400 From: Jason Wang To: mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jason Wang Subject: [PATCH V2 2/6] vhost_net: use vhost_add_used_and_signal_n() in vhost_zerocopy_signal_used() Date: Fri, 30 Aug 2013 12:29:18 +0800 Message-Id: <1377836962-49780-3-git-send-email-jasowang@redhat.com> In-Reply-To: <1377836962-49780-1-git-send-email-jasowang@redhat.com> References: <1377836962-49780-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-9.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable 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 We tend to batch the used adding and signaling in vhost_zerocopy_callback() which may result more than 100 used buffers to be updated in vhost_zerocopy_signal_used() in some cases. So wwitch to use vhost_add_used_and_signal_n() to avoid multiple calls to vhost_add_used_and_signal(). Which means much more less times of used index updating and memory barriers. Signed-off-by: Jason Wang --- drivers/vhost/net.c | 13 ++++++++----- 1 files changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 280ee66..8a6dd0d 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -281,7 +281,7 @@ static void vhost_zerocopy_signal_used(struct vhost_net *net, { struct vhost_net_virtqueue *nvq = container_of(vq, struct vhost_net_virtqueue, vq); - int i; + int i, add; int j = 0; for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) { @@ -289,14 +289,17 @@ static void vhost_zerocopy_signal_used(struct vhost_net *net, vhost_net_tx_err(net); if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { vq->heads[i].len = VHOST_DMA_CLEAR_LEN; - vhost_add_used_and_signal(vq->dev, vq, - vq->heads[i].id, 0); ++j; } else break; } - if (j) - nvq->done_idx = i; + while (j) { + add = min(UIO_MAXIOV - nvq->done_idx, j); + vhost_add_used_and_signal_n(vq->dev, vq, + &vq->heads[nvq->done_idx], add); + nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV; + j -= add; + } } static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)