From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-x541.google.com (mail-ed1-x541.google.com [IPv6:2a00:1450:4864:20::541]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 284583CB6C for ; Mon, 7 Jan 2019 15:54:27 -0500 (EST) Received: by mail-ed1-x541.google.com with SMTP id y20so2184638edw.9 for ; Mon, 07 Jan 2019 12:54:27 -0800 (PST) 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=J04PgGjRlOqVpKGWXjicJQ3+ijOcx9k2uOcVnFRnISo=; b=GFsV4m0gXRiMQoX+3PRFtDqcDHaX/RHKpYXWOy1+hQuOeX8/Z0epb/+vmkJqRxNtH1 P7X7Lvf+xezOybDXWznWjacYB219xpAfHpVBgUYFEUTEmAE/3njrSOuls0lI0UW0tdcS VGZn4EgZ1a6kXRO9cHivY++YlzFfH18upY3FcTQc3taHroUen7wReNvzq8HYipU344C5 DRDyJTo26lt8wAgiDGkVz58HMJ7xJaJuz33BFoQxmOUQzwO+T+D7wsM5BM41YHlvzvM6 W9fbGhOcSDXQRaSKYjzyHJb9PGN0F0a3T5jmIVRFvRsP9WlzmqVoattNktsx+nsEaKwW b3rg== 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=J04PgGjRlOqVpKGWXjicJQ3+ijOcx9k2uOcVnFRnISo=; b=BDShiFajBAImry1dA7toy9gonxI7zS/wBUA/LsSV+Dnu8HffWDSiyyUDCl0DhiM3g3 lef//gFNSpaRZASurr2JVTSmlYZ4KnMPWuqxUQyLYuVTpWg7wy2xIT1HNUKhJSQR+0kJ 5zmU3fQL54x4NpvRMYEn7zYJKjBaPhEKkH3uCI5BmOwKkE7new8/rPu86GC1uTJNPf3A jycSFTdBS4hb9Q/M6gIDmvcspGatQ99M7j0qVoRkuPaVvdzzE7dTAIlREb2G8n3WO8eQ JDRdXhvlLEuHXBki+lcePnKf0HfijIKQyQCNuG49qsW6J48xxb1aYLNQ3MkHbZR/xCOP AMSQ== X-Gm-Message-State: AA+aEWbhHfp2dIvXyW4/AM6O4Y0w9PZhtwM2+jMHeqp90761XMPYj4Co wy9US/ey7E9m9WPHVenVbLk= X-Google-Smtp-Source: AFSGD/VwcJRpvoPGLo+I5GEI6AqJoZ5YktcPeMzi8zUVaoQc8I5G4oXAccM3uTWco0mGBYli1YTr7g== X-Received: by 2002:a17:906:5118:: with SMTP id w24-v6mr48375661ejk.215.1546894466238; Mon, 07 Jan 2019 12:54:26 -0800 (PST) Received: from [192.168.8.147] (98.85.136.77.rev.sfr.net. [77.136.85.98]) by smtp.gmail.com with ESMTPSA id c53sm37423807ede.26.2019.01.07.12.54.23 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 07 Jan 2019 12:54:24 -0800 (PST) To: =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , netdev@vger.kernel.org Cc: cake@lists.bufferbloat.net, =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= References: <20190107194733.31138-1-toke@toke.dk> <20190107194733.31138-4-toke@toke.dk> From: Eric Dumazet Message-ID: <69d53b63-f7ed-3c6e-f191-43ec7fbd1735@gmail.com> Date: Mon, 7 Jan 2019 12:54:22 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190107194733.31138-4-toke@toke.dk> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [Cake] [PATCH 3/4] sch_api: Allow reducing queue backlog by a negative value X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Jan 2019 20:54:27 -0000 On 01/07/2019 11:47 AM, Toke Høiland-Jørgensen wrote: > From: Toke Høiland-Jørgensen > > With GSO splitting in sch_cake, we can decrease as well as increase the > qlen. To make it possible to signal this up the qdisc tree, change > qdisc_tree_reduce_backlog() to accept signed integer values as the number > of packets and bytes to reduce the backlog by. Not sure why this patch is needed, given we use u32 integers for q.qlen & qstats.backlog 0xFFFFFFFF for n is really -1 once folded... sch->q.qlen -= n; sch->qstats.backlog -= len;