From patchwork Fri Aug 16 05:16:28 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 2845477 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 2EBAA9F271 for ; Fri, 16 Aug 2013 05:30:22 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5B520201F2 for ; Fri, 16 Aug 2013 05:30:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 76C0B201ED for ; Fri, 16 Aug 2013 05:30:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752781Ab3HPF2v (ORCPT ); Fri, 16 Aug 2013 01:28:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:23993 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752186Ab3HPF2J (ORCPT ); Fri, 16 Aug 2013 01:28:09 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r7G5S41l014409 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 16 Aug 2013 01:28:05 -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-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r7G5Rns3001254; Fri, 16 Aug 2013 01:28:02 -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 4/6] vhost_net: determine whether or not to use zerocopy at one time Date: Fri, 16 Aug 2013 13:16:28 +0800 Message-Id: <1376630190-5912-5-git-send-email-jasowang@redhat.com> In-Reply-To: <1376630190-5912-1-git-send-email-jasowang@redhat.com> References: <1376630190-5912-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-9.7 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 Currently, even if the packet length is smaller than VHOST_GOODCOPY_LEN, if upend_idx != done_idx we still set zcopy_used to true and rollback this choice later. This could be avoided by determine zerocopy once by checking all conditions at one time before. Signed-off-by: Jason Wang --- drivers/vhost/net.c | 46 +++++++++++++++++++--------------------------- 1 files changed, 19 insertions(+), 27 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 8a6dd0d..70cab75 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -404,43 +404,35 @@ static void handle_tx(struct vhost_net *net) iov_length(nvq->hdr, s), hdr_size); break; } - zcopy_used = zcopy && (len >= VHOST_GOODCOPY_LEN || - nvq->upend_idx != nvq->done_idx); + + zcopy_used = zcopy && len >= VHOST_GOODCOPY_LEN + && nvq->upend_idx != nvq->done_idx + && vhost_net_tx_select_zcopy(net); /* use msg_control to pass vhost zerocopy ubuf info to skb */ if (zcopy_used) { + struct ubuf_info *ubuf; + ubuf = nvq->ubuf_info + nvq->upend_idx; + vq->heads[nvq->upend_idx].id = head; - if (!vhost_net_tx_select_zcopy(net) || - len < VHOST_GOODCOPY_LEN) { - /* copy don't need to wait for DMA done */ - vq->heads[nvq->upend_idx].len = - VHOST_DMA_DONE_LEN; - msg.msg_control = NULL; - msg.msg_controllen = 0; - ubufs = NULL; - } else { - struct ubuf_info *ubuf; - ubuf = nvq->ubuf_info + nvq->upend_idx; - - vq->heads[nvq->upend_idx].len = - VHOST_DMA_IN_PROGRESS; - ubuf->callback = vhost_zerocopy_callback; - ubuf->ctx = nvq->ubufs; - ubuf->desc = nvq->upend_idx; - msg.msg_control = ubuf; - msg.msg_controllen = sizeof(ubuf); - ubufs = nvq->ubufs; - kref_get(&ubufs->kref); - } + vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; + ubuf->callback = vhost_zerocopy_callback; + ubuf->ctx = nvq->ubufs; + ubuf->desc = nvq->upend_idx; + msg.msg_control = ubuf; + msg.msg_controllen = sizeof(ubuf); + ubufs = nvq->ubufs; + kref_get(&ubufs->kref); nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; - } else + } else { msg.msg_control = NULL; + ubufs = NULL; + } /* TODO: Check specific error and bomb out unless ENOBUFS? */ err = sock->ops->sendmsg(NULL, sock, &msg, len); if (unlikely(err < 0)) { if (zcopy_used) { - if (ubufs) - vhost_net_ubuf_put(ubufs); + vhost_net_ubuf_put(ubufs); nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) % UIO_MAXIOV; }