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=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL 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 5C634C433E0 for ; Fri, 22 Jan 2021 14:38:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 214E9239D1 for ; Fri, 22 Jan 2021 14:38:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728872AbhAVOiL (ORCPT ); Fri, 22 Jan 2021 09:38:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53828 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728746AbhAVOiA (ORCPT ); Fri, 22 Jan 2021 09:38:00 -0500 Received: from mail-vs1-xe32.google.com (mail-vs1-xe32.google.com [IPv6:2607:f8b0:4864:20::e32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 51351C06174A for ; Fri, 22 Jan 2021 06:37:15 -0800 (PST) Received: by mail-vs1-xe32.google.com with SMTP id 186so3074340vsz.13 for ; Fri, 22 Jan 2021 06:37:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=mWVqs/bI9wwr3tSnltmuSBGXJrYR6JzaEPLhsLUOb2w=; b=vNbj/DD/Msv/wACPFyJoexQkB0cazUlpSKezfd/S887z7Q+D4b+liGMCx6Lcm5Oi5+ SER7t52tQ4Q3rcb7i0UtijjXx7IUf/RdksI7IeS5z00VnkrQ9zkbFHjkVYP+/+vJgZ4n sOhH7Ai9fYfhG8KXKsYKiHthQn0YJ5apd+XVtW0tk7TAuQWHrIex1Zsd4qxaYOBMsf9A 4SHg4M5N1QrlOf40SWq9yHQmua6ZLpDMPreUd4sZOSkdYJZovIcUZQqBLnkCCL7zmQ7m 1Xl+JYyWdQtm8zI34oxxlE2iseZYi+MtcOcQcxgghiRea2/SNyYIhXiBt92fCl1bXOZG Oe6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=mWVqs/bI9wwr3tSnltmuSBGXJrYR6JzaEPLhsLUOb2w=; b=baV5vMR+g0Yurgf9d1Gxtsn2PWJU7Aw3oRuJdG0w3SdTkxcOp0ChLlN0quXix/AbHh Vmo35wO0EvKYEaV/jOMSk3M7BZrVf9JoJTjrJEDfAM4KAvvecaKN8hyGA76GcWA1EvOu EzxsJzRBHB326qEZJ2CyHkcK4/Wq8dqo9zCAk/Mnl6zYrlj6gr89sKdgvFPvNcuhMZq1 bLMfHpwrwdknXN5kjj5ze9Yh38myWPkgkRFsxJTF6T1FbYT2uCLfYiYfeX4VKCuk1UFe q0CM083itAIrutsZvZNisYoZeXmp8U9UcY1JNR9uYr/4SYOm2sXCrv3hwxYLjJmxhF8I FiFg== X-Gm-Message-State: AOAM532+9CYOGKqBPvMGn6E8JVOSzAtm9ahHHmn9NO51txnSBaXUKpUR C2zYsn5ZJTAEDg2RqEKs6lmPho+4VH9ncm+8M1yPPQ== X-Google-Smtp-Source: ABdhPJwZtwXw4vHnYNQuq50JH5MFq1Wr5I5Cdl81C1Rpehkkd0FyVI7zlSVPnsrquojJ0Q+m262lWqHvTkA5gLRmHm0= X-Received: by 2002:a67:7956:: with SMTP id u83mr951182vsc.54.1611326234187; Fri, 22 Jan 2021 06:37:14 -0800 (PST) MIME-Version: 1.0 References: <1611311242-6675-1-git-send-email-yangpc@wangsu.com> In-Reply-To: From: Neal Cardwell Date: Fri, 22 Jan 2021 09:36:57 -0500 Message-ID: Subject: Re: [PATCH net] tcp: fix TLP timer not set when CA_STATE changes from DISORDER to OPEN To: Eric Dumazet Cc: Pengcheng Yang , Yuchung Cheng , David Miller , netdev Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Jan 22, 2021 at 5:53 AM Eric Dumazet wrote: > > On Fri, Jan 22, 2021 at 11:28 AM Pengcheng Yang wrote: > > > > When CA_STATE is in DISORDER, the TLP timer is not set when receiving > > an ACK (a cumulative ACK covered out-of-order data) causes CA_STATE to > > change from DISORDER to OPEN. If the sender is app-limited, it can only > > wait for the RTO timer to expire and retransmit. > > > > The reason for this is that the TLP timer is set before CA_STATE changes > > in tcp_ack(), so we delay the time point of calling tcp_set_xmit_timer() > > until after tcp_fastretrans_alert() returns and remove the > > FLAG_SET_XMIT_TIMER from ack_flag when the RACK reorder timer is set. > > > > This commit has two additional benefits: > > 1) Make sure to reset RTO according to RFC6298 when receiving ACK, to > > avoid spurious RTO caused by RTO timer early expires. > > 2) Reduce the xmit timer reschedule once per ACK when the RACK reorder > > timer is set. > > > > Link: https://lore.kernel.org/netdev/1611139794-11254-1-git-send-email-yangpc@wangsu.com > > Signed-off-by: Pengcheng Yang > > Cc: Neal Cardwell > > --- > > This looks like a very nice patch, let me run packetdrill tests on it. > > By any chance, have you cooked a packetdrill test showing the issue > (failing on unpatched kernel) ? Thanks, Pengcheng. This patch looks good to me as well, assuming it passes our packetdrill tests. I agree with Eric that it would be good to have an explicit packetdrill test for this case. neal