From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf1-f68.google.com (mail-lf1-f68.google.com [209.85.167.68]) (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 0B4013B2A4 for ; Wed, 30 Jan 2019 17:59:20 -0500 (EST) Received: by mail-lf1-f68.google.com with SMTP id p6so889890lfc.1 for ; Wed, 30 Jan 2019 14:59:19 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:in-reply-to:references:date :message-id:mime-version:content-transfer-encoding; bh=Fx0rgP1bZH733zcxuZYlkTz78PAL/gA+3kScohxT24U=; b=cGs7GOuhKMOscQOtu9or3vlE9nhkTu0sVna+ZAln/y/Wg1ahTMJg9GiJEEPzQMtlpx Tp7yVsnz5jH0EPlQNm26uRgIAzVtetOswhm9dJYpsdMcW4TJ9GdyLf8yf8vbAyyu36De 1W8N0tiOsxHkFNTe69QkrbpVXwk+19+2ek6REQBNyGDpM7sJDn9YHtioST8BrhNli1+c 86XFFqViv3rNz3easxfsENoyvMrCTZb6436YwPqUvlFgMuLbWJkFP2GrUZ9ePOmJO4uK 4WNKUpkBPEEXeQuufHksUd3hQSy0w4NC5t4v6uu+hSJxjIjmiSkoP1jMuu9IIelWREcq C2iQ== X-Gm-Message-State: AJcUukfpjoXDPJGgEhYyPoPRDG3nYxNBuYlr5QAt7Ub5Jm4jQe5yPwok b5Iix5rIotX+dMnhsx0uv1fy13joBCDR4j86 X-Google-Smtp-Source: ALg8bN4K0JfukjicTOTdiYM+FxI4qJtfw6gAA0G3X+PSzV0ZzJUdmskpOg+07dkb6hcEGgKirFb5Zg== X-Received: by 2002:a19:4ace:: with SMTP id x197mr24669619lfa.39.1548889158756; Wed, 30 Jan 2019 14:59:18 -0800 (PST) Received: from alrua-x1.borgediget.toke.dk ([2a00:7660:6da:10::2]) by smtp.gmail.com with ESMTPSA id 4-v6sm467086ljw.84.2019.01.30.14.59.17 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 30 Jan 2019 14:59:18 -0800 (PST) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id B4A1F180496; Wed, 30 Jan 2019 23:59:16 +0100 (CET) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Pete Heist , Cake List In-Reply-To: <15FB76CC-44B2-496B-80EC-8D00AD2AF9B7@heistp.net> References: <15FB76CC-44B2-496B-80EC-8D00AD2AF9B7@heistp.net> X-Clacks-Overhead: GNU Terry Pratchett Date: Wed, 30 Jan 2019 23:59:16 +0100 Message-ID: <87zhrhiwfv.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Cake] lockup with multiple cake instances on 3.16.7 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: Wed, 30 Jan 2019 22:59:20 -0000 Pete Heist writes: > I=E2=80=99m seeing a lockup with cake on 3.16.7 with 64-bit Intel when ad= ding > more than 4 cake instances. I=E2=80=99m using cake and tc-adv from head. = Does > anyone have an idea what this could be? Looks like it's a compatibility issue with old kernels. Could you please check if the latest commit in the github repo fixes this? :) The explanation, copied from that commit: > The qdisc stats dumping was changed in 4.8 (by commit > edb09eb17ed89eaa82a52dd306beac93e292b485) to be lockless and moving the > responsibility for taking the qdisc root lock into the qdisc itself. Cake > inherited this from FQ-CoDel, but it leads to deadlocks on old kernels > where the core stats dumping code still takes the root qdisc lock. -Toke