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=-2.1 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 DC974CA9EA0 for ; Tue, 22 Oct 2019 17:28:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ADEE5206C2 for ; Tue, 22 Oct 2019 17:28:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ec0zUAIt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732290AbfJVR23 (ORCPT ); Tue, 22 Oct 2019 13:28:29 -0400 Received: from mail-pl1-f193.google.com ([209.85.214.193]:43932 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731893AbfJVR23 (ORCPT ); Tue, 22 Oct 2019 13:28:29 -0400 Received: by mail-pl1-f193.google.com with SMTP id v5so3939846ply.10; Tue, 22 Oct 2019 10:28:28 -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=cuy7rm01bS2uzKpuJkB6ZeWcPvBBR+3UcGaSjYaEpcU=; b=ec0zUAItUL6RJ2RVYfJvwoEYOfMW0BhKGxEksvTfGQOfKzVufjUm0yCHY6K1A5lz/f 9k1D5XfWvjvvfU6Ex237n0yfmbvyeXD+jwHKajOMXrpywTG2v4W7l5vrTQdrOlU13uDo hzTe+fhaGD/M2dlCVv7qHcUH72eNBL1UKF3XQta/AZUyZmt7opJ+9fmIDpZaneswO/Jn KdLHCUMqwmdWcKQTww4rGB4ACqVe6WzJroJFheMWeUWVRgVit95Ao611pLbumD3Ogd+H 8rY2IenfZwffNmLm19SyqejPCx45vH8NKTPQIXlpoN3b+Yf+Z8CLwjVHqho2Wa5ezo0j mklA== 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=cuy7rm01bS2uzKpuJkB6ZeWcPvBBR+3UcGaSjYaEpcU=; b=IqxtCjt2ZlWPtesJ3p1ooJumy5493aoo/Pcux5J+xrrZuqpsILAyo9hR8nRcX1wU8x QrDf/W9xNdl/s8PWYxBlByMztleA1x9UkVx4ZFEvZIexRR/wh17kcw+3wBi2LIy1iRd1 KvWGMTdxCBrXlT4ZXZqcChiQ6wVp5loque/mPJ+g6zK2PEcDDmRSOtcZpWV64NvfDOy5 N1xKxGp9oayy0Rx64zfGK/4tjniqK87l3W1VtX79YOeVIauFcaDdJEBCwcUY6q6RK/vZ euhSMDPtxwq47KHpuoHExx1nxe1jMLTfkFv42up7mtAxdBQ3NKxJ3mMXgYQ+dZTHlkDL IBnA== X-Gm-Message-State: APjAAAWuClfuOmjdR/NtfUMIEYHycqXYobpo4T4W2wJxhLehnd1uMIr7 1gpOY4O+w7zQtjX70n/8bfH2Ue2S X-Google-Smtp-Source: APXvYqyslXSZO3TgmoOzqcBlon/yueY8YrAeZokRMwywOrqncUQmnFAguKWe1O6Wgvga361fBSgS7w== X-Received: by 2002:a17:902:b196:: with SMTP id s22mr5157905plr.10.1571765308381; Tue, 22 Oct 2019 10:28:28 -0700 (PDT) Received: from ?IPv6:2620:15c:2c1:200:55c7:81e6:c7d8:94b? ([2620:15c:2c1:200:55c7:81e6:c7d8:94b]) by smtp.gmail.com with ESMTPSA id o9sm24848204pfp.67.2019.10.22.10.28.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 22 Oct 2019 10:28:27 -0700 (PDT) Subject: Re: [PATCH v2] net: sch_generic: Use pfifo_fast as fallback scheduler for CAN hardware To: Stephen Hemminger , Marc Kleine-Budde Cc: Vincent Prince , jiri@resnulli.us, jhs@mojatatu.com, netdev@vger.kernel.org, dave.taht@gmail.com, linux-can@vger.kernel.org, kernel@pengutronix.de, xiyou.wangcong@gmail.com, davem@davemloft.net References: <20190327165632.10711-1-mkl@pengutronix.de> <1571750597-14030-1-git-send-email-vincent.prince.fr@gmail.com> <84b8ce24-fe5d-ead0-0d1d-03ea24b36f71@pengutronix.de> <20191022094254.489fd6a4@hermes.lan> From: Eric Dumazet Message-ID: Date: Tue, 22 Oct 2019 10:28:26 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20191022094254.489fd6a4@hermes.lan> Content-Type: text/plain; charset=windows-1252 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 10/22/19 9:42 AM, Stephen Hemminger wrote: > Why not fix fq_codel to return the same errors as other qdisc? > I believe the same problem would happen with any qdisc not doing tail drops. Do we really want to enforce all qdisc to have a common drop strategy ? For example, FQ could implement a strategy dropping the oldest packet in the queue, which is absolutely not related to the enqueue order.