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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 0E78DC28CF6 for ; Sat, 28 Jul 2018 07:43:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9BB5E2088E for ; Sat, 28 Jul 2018 07:43:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="WYTyyUuH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9BB5E2088E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726328AbeG1JIs (ORCPT ); Sat, 28 Jul 2018 05:08:48 -0400 Received: from mail-io0-f195.google.com ([209.85.223.195]:37517 "EHLO mail-io0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726061AbeG1JIs (ORCPT ); Sat, 28 Jul 2018 05:08:48 -0400 Received: by mail-io0-f195.google.com with SMTP id z19-v6so5964571ioh.4; Sat, 28 Jul 2018 00:43:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=oUzh+UPnEEG3jYHC+Jrm2o27FVmC0oqOoqYaBgJA4/M=; b=WYTyyUuHerxe2tL9YCg/v4nA1PaOsARSmJY69vgy+rBKccMupdrdYXVYI7aqPVYZe6 hVfp4pbTB28SVicdXE+GCEVavGyDDhplK5UaV1EHFU/0k6Jsd0uVNYggZVt2tEy0ygu/ SJ9obhgCrbCy5I1ZJtyppAmldCKDdrQU91dcqE33X6RjEOHiv6pXrF5MDcMd3mdGxyrB cu18M4zjxelZXsqO7VhRr6VF44O/HHAbDV1uvcr/ky8pkXEOYnAVRkIjQy9i3UEU/yjt E1s+4z4letXgTZhvWQupCx7xOe1kvDz3nB+EFcjPcP7ZNpIBH2b9zJKvQx2B66RHrbuC iN9g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=oUzh+UPnEEG3jYHC+Jrm2o27FVmC0oqOoqYaBgJA4/M=; b=AteFM1HL2CB+/Dml40cT7sCcc6Vbz9Z8X/PMoqdGxO6FsCTCJDptjPKJp57ZU8VHPh nwDjR6aMlaGXfKio4A8TF1p4W9PD3/IPTdateA6aL/bQdxoTPkLxp4QAlQrvIw3NUiKi Pjdaqq8KPCPaSvhi2nxXjs9STUbqCL1+m0eDhXfTYtXanXMyzbgf5dXraWM6D3YmVTaV XvbPJO/MQUY8rRiDOLOmdhLiVNHeDT6OAVzprWh0gM82tUVPFEvuzfyYa3MD/2K9uWYw 9ewfwToCOax9PevSI1OoDf5Dks6YCSEASkg1KZsg6GOjfJctiqM8bbkhfSNGwRb68Gqo fJjA== X-Gm-Message-State: AOUpUlHxX+JfziCsy6kUs5/Z0pyf4+Cf8E+8XM0aYGQUMMWLJMqilOzg fZHcMPQibFMHLv+QF95ik1HrTye+1BECXD7iFaU= X-Google-Smtp-Source: AAOMgpemkkc2eShPDMi3i7YW9auJYOc3c3RECUbngEItxbwE6kPEpAo9GvmB455x9WhLRwIpJlS+WH9gD6REwJ2XEeY= X-Received: by 2002:a6b:c8c8:: with SMTP id y191-v6mr7527394iof.295.1532763795542; Sat, 28 Jul 2018 00:43:15 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a6b:7a47:0:0:0:0:0 with HTTP; Sat, 28 Jul 2018 00:42:35 -0700 (PDT) In-Reply-To: References: <1532746900-11710-1-git-send-email-laoar.shao@gmail.com> From: Yafang Shao Date: Sat, 28 Jul 2018 15:42:35 +0800 Message-ID: Subject: Re: [PATCH net-next 1/2] tcp: call tcp_drop() in tcp collapse To: Eric Dumazet Cc: David Miller , netdev , LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 28, 2018 at 11:38 AM, Eric Dumazet wrote: > On Fri, Jul 27, 2018 at 8:35 PM Yafang Shao wrote: > >> So what about LINUX_MIB_TCPOFOMERGE ? >> Regarding LINUX_MIB_TCPOFOMERGE, a skb is already covered by another >> skb, is that dropping the packet or simply lowering the memory >> overhead ? > > What do you think ? > > If you receive two times the same payload, don't you have to drop one > of the duplicate ? > > There is a a big difference between the two cases. If the drop caused some data lost (which may then cause retransmition or something), then this is a really DROP. While if the drop won't cause any data lost, meaning it is a non-harmful behavior, I think it should not be defined as DROP. This is my suggestion anyway. Thanks Yafang