From patchwork Fri Jul 20 00:15:18 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 10535817 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id E9A9960547 for ; Fri, 20 Jul 2018 00:16:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D65B1284DC for ; Fri, 20 Jul 2018 00:16:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CAEE3285EB; Fri, 20 Jul 2018 00:16:32 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 62C6F284DC for ; Fri, 20 Jul 2018 00:16:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731462AbeGTBBZ (ORCPT ); Thu, 19 Jul 2018 21:01:25 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:37738 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731446AbeGTBBZ (ORCPT ); Thu, 19 Jul 2018 21:01:25 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B9D4A400B45C; Fri, 20 Jul 2018 00:15:51 +0000 (UTC) Received: from jason-ThinkPad-T450s.redhat.com (ovpn-12-42.pek2.redhat.com [10.72.12.42]) by smtp.corp.redhat.com (Postfix) with ESMTP id C891C2026D6B; Fri, 20 Jul 2018 00:15:48 +0000 (UTC) From: Jason Wang To: mst@redhat.com, jasowang@redhat.com, netdev@vger.kernel.org Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next 6/9] vhost_net: split out datacopy logic Date: Fri, 20 Jul 2018 08:15:18 +0800 Message-Id: <1532045721-4958-7-git-send-email-jasowang@redhat.com> In-Reply-To: <1532045721-4958-1-git-send-email-jasowang@redhat.com> References: <1532045721-4958-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Fri, 20 Jul 2018 00:15:51 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Fri, 20 Jul 2018 00:15:51 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jasowang@redhat.com' RCPT:'' Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Instead of mixing zerocopy and datacopy logics, this patch tries to split datacopy logic out. This results for a more compact code and ad-hoc optimization could be done on top more easily. Signed-off-by: Jason Wang --- drivers/vhost/net.c | 110 ++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 90 insertions(+), 20 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index f59b615..9cef0b2 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -520,9 +520,7 @@ static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len) !vhost_vq_avail_empty(vq->dev, vq); } -/* Expects to be always run from workqueue - which acts as - * read-size critical section for our kind of RCU. */ -static void handle_tx(struct vhost_net *net) +static void handle_tx_copy(struct vhost_net *net, struct socket *sock) { struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; struct vhost_virtqueue *vq = &nvq->vq; @@ -537,30 +535,76 @@ static void handle_tx(struct vhost_net *net) }; size_t len, total_len = 0; int err; - struct socket *sock; - struct vhost_net_ubuf_ref *uninitialized_var(ubufs); - bool zcopy, zcopy_used; int sent_pkts = 0; - mutex_lock(&vq->mutex); - sock = vq->private_data; - if (!sock) - goto out; + for (;;) { + bool busyloop_intr = false; - if (!vq_iotlb_prefetch(vq)) - goto out; + head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, + &busyloop_intr); + /* On error, stop handling until the next kick. */ + if (unlikely(head < 0)) + break; + /* Nothing new? Wait for eventfd to tell us they refilled. */ + if (head == vq->num) { + if (unlikely(busyloop_intr)) { + vhost_poll_queue(&vq->poll); + } else if (unlikely(vhost_enable_notify(&net->dev, + vq))) { + vhost_disable_notify(&net->dev, vq); + continue; + } + break; + } - vhost_disable_notify(&net->dev, vq); - vhost_net_disable_vq(net, vq); + total_len += len; + if (tx_can_batch(vq, total_len)) + msg.msg_flags |= MSG_MORE; + else + msg.msg_flags &= ~MSG_MORE; + + /* TODO: Check specific error and bomb out unless ENOBUFS? */ + err = sock->ops->sendmsg(sock, &msg, len); + if (unlikely(err < 0)) { + vhost_discard_vq_desc(vq, 1); + vhost_net_enable_vq(net, vq); + break; + } + if (err != len) + pr_debug("Truncated TX packet: len %d != %zd\n", + err, len); + vhost_add_used_and_signal(&net->dev, vq, head, 0); + if (vhost_exceeds_weight(++sent_pkts, total_len)) { + vhost_poll_queue(&vq->poll); + break; + } + } +} - zcopy = nvq->ubufs; +static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) +{ + struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; + struct vhost_virtqueue *vq = &nvq->vq; + unsigned out, in; + int head; + struct msghdr msg = { + .msg_name = NULL, + .msg_namelen = 0, + .msg_control = NULL, + .msg_controllen = 0, + .msg_flags = MSG_DONTWAIT, + }; + size_t len, total_len = 0; + int err; + struct vhost_net_ubuf_ref *uninitialized_var(ubufs); + bool zcopy_used; + int sent_pkts = 0; for (;;) { bool busyloop_intr; /* Release DMAs done buffers first */ - if (zcopy) - vhost_zerocopy_signal_used(net, vq); + vhost_zerocopy_signal_used(net, vq); busyloop_intr = false; head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, @@ -579,9 +623,9 @@ static void handle_tx(struct vhost_net *net) break; } - zcopy_used = zcopy && len >= VHOST_GOODCOPY_LEN - && !vhost_exceeds_maxpend(net) - && vhost_net_tx_select_zcopy(net); + zcopy_used = len >= VHOST_GOODCOPY_LEN + && !vhost_exceeds_maxpend(net) + && vhost_net_tx_select_zcopy(net); /* use msg_control to pass vhost zerocopy ubuf info to skb */ if (zcopy_used) { @@ -636,6 +680,32 @@ static void handle_tx(struct vhost_net *net) break; } } +} + +/* Expects to be always run from workqueue - which acts as + * read-size critical section for our kind of RCU. */ +static void handle_tx(struct vhost_net *net) +{ + struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; + struct vhost_virtqueue *vq = &nvq->vq; + struct socket *sock; + + mutex_lock(&vq->mutex); + sock = vq->private_data; + if (!sock) + goto out; + + if (!vq_iotlb_prefetch(vq)) + goto out; + + vhost_disable_notify(&net->dev, vq); + vhost_net_disable_vq(net, vq); + + if (vhost_sock_zcopy(sock)) + handle_tx_zerocopy(net, sock); + else + handle_tx_copy(net, sock); + out: mutex_unlock(&vq->mutex); }