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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_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 1B1CCC43381 for ; Tue, 26 Feb 2019 23:51:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D749E218E0 for ; Tue, 26 Feb 2019 23:51:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="vPkE9Vj5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729038AbfBZXvb (ORCPT ); Tue, 26 Feb 2019 18:51:31 -0500 Received: from mail-pg1-f173.google.com ([209.85.215.173]:41086 "EHLO mail-pg1-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727998AbfBZXva (ORCPT ); Tue, 26 Feb 2019 18:51:30 -0500 Received: by mail-pg1-f173.google.com with SMTP id m1so6973980pgq.8 for ; Tue, 26 Feb 2019 15:51:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=K6zbFHj6wCBxhknf7SiorfzUIqLEhj0fUQ73fyXXB0Q=; b=vPkE9Vj5G2bJxMDlDI0Hsy6yGZAuiKlnrrBhdPBBtgQwPVsf9RsaZK8BZvGhiTfxVP vumBCoRqPrK/TCLf0nteh3YMlpO6lS18aY38twlsCXznFrfP5QhKrRweqP1fpyYDn8zz ZqSHjZu83kRFI7TllWlknk76ZoOqS2xwL3ubpGlXo0euMa7w7VhqS50a6mY16eZoY90z E8rDZeCBR4gKqXv6iZDzYQsw5ESQgP31hrYxJNhjIkYvuH/J9K/4ebRZ8RqhRIdpCb0w gJryou4UDQfNCg9D6MKltVEf92iahdcLvPa+ybKpHcgLE41cIhzsKOtO4BD4diiLKfYM Tz2g== 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=K6zbFHj6wCBxhknf7SiorfzUIqLEhj0fUQ73fyXXB0Q=; b=fR5MaOqeduGVL2W5RyLD3D9JYaBBH5jjwox9lW0LFryt7AGilyMgsfnP6h9ewq+Bqt yhGy9/QObPoXHoSiI7McyOXECRaaiemKi/a9NHxOnKh5NJkpta5IvZWBSZh4PeT+wqmR 2iCFmnfuI6hhSwrxBiuHSwhxhYRPExfG+I27vG8bdU8EY3dOF3WUtNbZSBGyhkoR91ka PRQOUF6MUStm0iXKWil+drIiak+TEp7tnQCK5rtJTEU/inmBsECarOYPPzRovw//zgLo wujr9rhNbEA5hvwUG5zXTOJunfCEXrNLn5YMf5rYtRP0envAKmyoWRdZJZJnY5xeL515 L8iA== X-Gm-Message-State: AHQUAuY7Z4VafDczN3U7fM/6IUVNvLqODOeg69b7JxDKlAbf1+enG5KT wy+QccACFMLhweoXisLsxnkNBR8HQbilP9b66qNKQW7e X-Google-Smtp-Source: AHgI3IavkKxUERCJ0/+jSxhANgvQsrhQNUCgfWUgyMWYWBWTjm8r5Me4yVLP9SJTivYiR+rSdl/i1JDqYyNzgIU1SVo= X-Received: by 2002:a63:d442:: with SMTP id i2mr29100pgj.246.1551225089897; Tue, 26 Feb 2019 15:51:29 -0800 (PST) MIME-Version: 1.0 References: <5fb87db3-d5bd-714b-213d-6821f4bf37da@gmail.com> In-Reply-To: From: Cong Wang Date: Tue, 26 Feb 2019 15:51:17 -0800 Message-ID: Subject: Re: [BUG] net/sched : qlen can not really be per cpu ? To: Eric Dumazet Cc: John Fastabend , Networking , Jamal Hadi Salim , Jiri Pirko Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Feb 26, 2019 at 3:19 PM Eric Dumazet wrote: > > > > On 02/25/2019 10:42 PM, Eric Dumazet wrote: > > HTB + pfifo_fast as a leaf qdisc hits badly the following warning in htb_activate() : > > > > WARN_ON(cl->level || !cl->leaf.q || !cl->leaf.q->q.qlen); > > > > This is because pfifo_fast does not update sch->q.qlen, but per cpu counters. > > So cl->leaf.q->q.qlen is zero. > > > > HFSC, CBQ, DRR, QFQ have the same problem. > > > > Any ideas how we can fix this ? > > What about something simple for stable ? > ( I yet have to boot/test this ) Is merely updating qlen sufficient for fixing it? I thought it is because of the lack of qdisc_tree_reduce_backlog() in pfifo_fast.