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=-2.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 06212C0650E for ; Wed, 3 Jul 2019 09:34:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B9F7F21882 for ; Wed, 3 Jul 2019 09:34:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="rNZ27E06" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726434AbfGCJey (ORCPT ); Wed, 3 Jul 2019 05:34:54 -0400 Received: from mail-wr1-f54.google.com ([209.85.221.54]:42579 "EHLO mail-wr1-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725820AbfGCJey (ORCPT ); Wed, 3 Jul 2019 05:34:54 -0400 Received: by mail-wr1-f54.google.com with SMTP id a10so862006wrp.9 for ; Wed, 03 Jul 2019 02:34:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=ZCaGvqtjPu+wMpfCpkHUU1Nn3NIhv5ULL6eB8EUuNns=; b=rNZ27E06UkQ5XV4bn8nk4JRTjCU+cDmJeaA5YkduS6EGJvmw7E9OkIK80ViY5JlHUQ hWsrMfyYuzvTX1pwp0cVvdK0DVV2ipZSKG0YTcxno2NT9QCoaLndilCPGICgTu6jCCBY Fwil2mIUT0eH1InKk1noNNcLa2CsmueBNib2z8sH8h1sX0ktYsC4feJcjkl08gRSgMCp GOH57orM0Upb1T4it+hFFlPDhMny0cskZylyLgUnl9NS+L/ltXWxv7seq8hnas9gc7WS ava8iNsQFYC1qdZw38wHu9TstGYvV9y8F9RIR3yysXFaZWOQPl6yYVqyPt07D6/xso8b Hzzg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=ZCaGvqtjPu+wMpfCpkHUU1Nn3NIhv5ULL6eB8EUuNns=; b=f0pmeD0SSrIIwmwBPTJMAz5qAYuWpk+uD9Q9DU6ZLF30aXkvzc16H/sWURIkd5zPfA 6v50LZ85pH61meds0z8vygvUeTz2vR60BnONBB7A+bePpRlZ8K6Ag4T5ZbUjqNgNcgZ3 w1h9KIIOFDS9cT6O5eTnziNmt+7Edu1YFgdMtJ9U5MqJvRWCRbDTkoBlb1LNxDtuMWLn Xz+TXhafBGcFggAm8Qo5J+nIYoVbbzWyhZnXyj98AO1CVPt5egCrGNDHVBG22cOUWutx GkahsAmWK5baEc1gKE5hhGGpXC3NV71Ahcj7yLD0Bi4bFBgNp8zS3EsBmdF7tTfNKUE7 BA1A== X-Gm-Message-State: APjAAAVzlEAu6h0hdlDjtC18ta2ECNCWRTvXcteRdjXi12XAQ0L445Jf VOkpuv1yam0IeS5YudHYNatl+K2v X-Google-Smtp-Source: APXvYqz7uxKnONomCjeeY+VnTRzGh/zhO0udNyOKPD102SDYOPTlpe7nY7taOd4gQ8mUJ00cX+nJRw== X-Received: by 2002:adf:e446:: with SMTP id t6mr28920171wrm.115.1562146492667; Wed, 03 Jul 2019 02:34:52 -0700 (PDT) Received: from [192.168.8.147] (196.166.185.81.rev.sfr.net. [81.185.166.196]) by smtp.gmail.com with ESMTPSA id p4sm480236wrs.35.2019.07.03.02.34.51 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Wed, 03 Jul 2019 02:34:52 -0700 (PDT) Subject: Re: Shall we add some note info for tcp_min_snd_mss? To: ZhangXiao , edumazet@google.com, davem@davemloft.net Cc: netdev@vger.kernel.org References: <5D1C68C8.6020408@windriver.com> From: Eric Dumazet Message-ID: <564a6863-0db9-a07b-0cfc-b41ea8e9c9f8@gmail.com> Date: Wed, 3 Jul 2019 11:34:50 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <5D1C68C8.6020408@windriver.com> Content-Type: text/plain; charset=gbk Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 7/3/19 1:35 AM, ZhangXiao wrote: > Hi David & Eric, > > Commit 5f3e2bf0 (tcp: add tcp_min_snd_mss sysctl) add a new interface to > adjust network. While if this variable been set too large, for example > larger then (MTU - 40), the net link maybe damaged. So, how about adding > some warning messages for the operator/administrator? In document, or in > source code. What kind of warning message do you envision exactly ? The sysctl is global, devices MTU can be quite arbitrary. Like almost all sysctls, sysadmins are supposed to know what they are doing.