From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD39FC433F5 for ; Tue, 14 Sep 2021 00:18:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B133660C51 for ; Tue, 14 Sep 2021 00:18:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236547AbhINAT3 (ORCPT ); Mon, 13 Sep 2021 20:19:29 -0400 Received: from prt-mail.chinatelecom.cn ([42.123.76.222]:37770 "EHLO chinatelecom.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S229482AbhINAT2 (ORCPT ); Mon, 13 Sep 2021 20:19:28 -0400 HMM_SOURCE_IP: 172.18.0.218:47798.281646273 HMM_ATTACHE_NUM: 0000 HMM_SOURCE_TYPE: SMTP Received: from clientip-110.87.95.153 (unknown [172.18.0.218]) by chinatelecom.cn (HERMES) with SMTP id 9D2542800AF; Tue, 14 Sep 2021 08:17:56 +0800 (CST) X-189-SAVE-TO-SEND: zhenggy@chinatelecom.cn Received: from ([172.18.0.218]) by app0025 with ESMTP id 23f18b7698bb4a238727e0331becb224 for liyonglong@chinatelecom.cn; Tue, 14 Sep 2021 08:18:08 CST X-Transaction-ID: 23f18b7698bb4a238727e0331becb224 X-Real-From: zhenggy@chinatelecom.cn X-Receive-IP: 172.18.0.218 Sender: zhenggy@chinatelecom.cn Subject: Re: [PATCH v3] tcp: fix tp->undo_retrans accounting in tcp_sacktag_one() To: Neal Cardwell , Yuchung Cheng , edumazet@google.com, Jakub Kicinski Cc: netdev , David Miller , Hideaki YOSHIFUJI , David Ahern , qitiepeng@chinatelecom.cn, wujianguo@chinatelecom.cn, liyonglong@chinatelecom.cn References: <1630314010-15792-1-git-send-email-zhenggy@chinatelecom.cn> From: zhenggy Message-ID: Date: Tue, 14 Sep 2021 08:17:49 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Thanks very much for all your comments, i will repost a v4 patch later. 在 2021/9/14 0:27, Neal Cardwell 写道: > On Mon, Sep 13, 2021 at 12:11 PM Yuchung Cheng wrote: >> >> On Mon, Sep 13, 2021 at 8:49 AM Eric Dumazet wrote: >>> >>> On Mon, Sep 13, 2021 at 3:51 AM zhenggy wrote: >>>> >>>> Commit 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit >>>> time") may directly retrans a multiple segments TSO/GSO packet without >>>> split, Since this commit, we can no longer assume that a retransmitted >>>> packet is a single segment. >>>> >>>> This patch fixes the tp->undo_retrans accounting in tcp_sacktag_one() >>>> that use the actual segments(pcount) of the retransmitted packet. >>>> >>>> Before that commit (10d3be569243), the assumption underlying the >>>> tp->undo_retrans-- seems correct. >>>> >>>> Fixes: 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit time") >>>> >>> >>> nit: We normally do not add an empty line between Fixes: tag and others. >>> >>> Reviewed-by: Eric Dumazet >> Acked-by: Yuchung Cheng >> >> This is a nice fix that would increase the effectiveness of TCP undo >> in high-speed networks. > > Yes, thanks for the fix! > > Acked-by: Neal Cardwell > > neal >