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GET /api/1.2/patches/809888/?format=api
{ "id": 809888, "url": "http://patchwork.ozlabs.org/api/1.2/patches/809888/?format=api", "web_url": "http://patchwork.ozlabs.org/project/netdev/patch/1504574525-4711-1-git-send-email-jasowang@redhat.com/", "project": { "id": 7, "url": "http://patchwork.ozlabs.org/api/1.2/projects/7/?format=api", "name": "Linux network development", "link_name": "netdev", "list_id": "netdev.vger.kernel.org", "list_email": "netdev@vger.kernel.org", "web_url": null, "scm_url": null, "webscm_url": null, "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<1504574525-4711-1-git-send-email-jasowang@redhat.com>", "list_archive_url": null, "date": "2017-09-05T01:22:05", "name": "[net,V2] vhost_net: correctly check tx avail during rx busy polling", "commit_ref": null, "pull_url": null, "state": "accepted", "archived": true, "hash": "a8a1549bdb0b1c9726443f40fae4a5bcd0efd669", "submitter": { "id": 5225, "url": "http://patchwork.ozlabs.org/api/1.2/people/5225/?format=api", "name": "Jason Wang", "email": "jasowang@redhat.com" }, "delegate": { "id": 34, "url": "http://patchwork.ozlabs.org/api/1.2/users/34/?format=api", "username": "davem", "first_name": "David", "last_name": "Miller", "email": "davem@davemloft.net" }, "mbox": "http://patchwork.ozlabs.org/project/netdev/patch/1504574525-4711-1-git-send-email-jasowang@redhat.com/mbox/", "series": [ { "id": 1476, "url": "http://patchwork.ozlabs.org/api/1.2/series/1476/?format=api", "web_url": "http://patchwork.ozlabs.org/project/netdev/list/?series=1476", "date": "2017-09-05T01:22:05", "name": "[net,V2] vhost_net: correctly check tx avail during rx busy polling", "version": 2, "mbox": "http://patchwork.ozlabs.org/series/1476/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/809888/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/809888/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<netdev-owner@vger.kernel.org>", "X-Original-To": "patchwork-incoming@ozlabs.org", "Delivered-To": "patchwork-incoming@ozlabs.org", "Authentication-Results": [ "ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=netdev-owner@vger.kernel.org;\n\treceiver=<UNKNOWN>)", "ext-mx02.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com", "ext-mx02.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=jasowang@redhat.com" ], "Received": [ "from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xmTV334QKz9s7f\n\tfor <patchwork-incoming@ozlabs.org>;\n\tTue, 5 Sep 2017 11:22:35 +1000 (AEST)", "(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1754085AbdIEBWO (ORCPT <rfc822;patchwork-incoming@ozlabs.org>);\n\tMon, 4 Sep 2017 21:22:14 -0400", "from mx1.redhat.com ([209.132.183.28]:56114 \"EHLO mx1.redhat.com\"\n\trhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP\n\tid S1754066AbdIEBWN (ORCPT <rfc822;netdev@vger.kernel.org>);\n\tMon, 4 Sep 2017 21:22:13 -0400", "from smtp.corp.redhat.com\n\t(int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mx1.redhat.com (Postfix) with ESMTPS id 02F87806D2;\n\tTue, 5 Sep 2017 01:22:13 +0000 (UTC)", "from jason-ThinkPad-T450s.redhat.com (ovpn-12-71.pek2.redhat.com\n\t[10.72.12.71])\n\tby smtp.corp.redhat.com (Postfix) with ESMTP id 4A7F55D722;\n\tTue, 5 Sep 2017 01:22:08 +0000 (UTC)" ], "DMARC-Filter": "OpenDMARC Filter v1.3.2 mx1.redhat.com 02F87806D2", "From": "Jason Wang <jasowang@redhat.com>", "To": "mst@redhat.com, jasowang@redhat.com, netdev@vger.kernel.org", "Cc": "kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,\n\tlinux-kernel@vger.kernel.org", "Subject": "[PATCH net V2] vhost_net: correctly check tx avail during rx busy\n\tpolling", "Date": "Tue, 5 Sep 2017 09:22:05 +0800", "Message-Id": "<1504574525-4711-1-git-send-email-jasowang@redhat.com>", "X-Scanned-By": "MIMEDefang 2.79 on 10.5.11.14", "X-Greylist": "Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.26]);\n\tTue, 05 Sep 2017 01:22:13 +0000 (UTC)", "Sender": "netdev-owner@vger.kernel.org", "Precedence": "bulk", "List-ID": "<netdev.vger.kernel.org>", "X-Mailing-List": "netdev@vger.kernel.org" }, "content": "We check tx avail through vhost_enable_notify() in the past which is\nwrong since it only checks whether or not guest has filled more\navailable buffer since last avail idx synchronization which was just\ndone by vhost_vq_avail_empty() before. What we really want is checking\npending buffers in the avail ring. Fix this by calling\nvhost_vq_avail_empty() instead.\n\nThis issue could be noticed by doing netperf TCP_RR benchmark as\nclient from guest (but not host). With this fix, TCP_RR from guest to\nlocalhost restores from 1375.91 trans per sec to 55235.28 trans per\nsec on my laptop (Intel(R) Core(TM) i7-5600U CPU @ 2.60GHz).\n\nFixes: 030881372460 (\"vhost_net: basic polling support\")\nSigned-off-by: Jason Wang <jasowang@redhat.com>\n---\n- The patch is needed for -stable\n- Changes from V1: enable vq notification when needed\n---\n drivers/vhost/net.c | 7 ++++++-\n 1 file changed, 6 insertions(+), 1 deletion(-)", "diff": "diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c\nindex 06d0448..1c75572 100644\n--- a/drivers/vhost/net.c\n+++ b/drivers/vhost/net.c\n@@ -634,8 +634,13 @@ static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk)\n \n \t\tpreempt_enable();\n \n-\t\tif (vhost_enable_notify(&net->dev, vq))\n+\t\tif (!vhost_vq_avail_empty(&net->dev, vq))\n \t\t\tvhost_poll_queue(&vq->poll);\n+\t\telse if (unlikely(vhost_enable_notify(&net->dev, vq))) {\n+\t\t\tvhost_disable_notify(&net->dev, vq);\n+\t\t\tvhost_poll_queue(&vq->poll);\n+\t\t}\n+\n \t\tmutex_unlock(&vq->mutex);\n \n \t\tlen = peek_head_len(rvq, sk);\n", "prefixes": [ "net", "V2" ] }