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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 88637C433EF for ; Wed, 6 Apr 2022 15:20:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235782AbiDFPWP (ORCPT ); Wed, 6 Apr 2022 11:22:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235914AbiDFPV3 (ORCPT ); Wed, 6 Apr 2022 11:21:29 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 827BFBE3B for ; Wed, 6 Apr 2022 05:21:37 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0F4261516; Wed, 6 Apr 2022 05:21:37 -0700 (PDT) Received: from [192.168.178.6] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6B1DB3F718; Wed, 6 Apr 2022 05:21:35 -0700 (PDT) Message-ID: <000457c2-57af-95e3-7dff-2cbd99f0de5f@arm.com> Date: Wed, 6 Apr 2022 14:21:19 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [Linux 5.18-rc1] WARNING: CPU: 1 PID: 0 at kernel/sched/fair.c:3355 update_blocked_averages Content-Language: en-US To: Ammar Faizi , Linux Kernel Mailing List Cc: Ben Segall , Daniel Bristot de Oliveira , GNU/Weeb Mailing List , Ingo Molnar , Juri Lelli , Mel Gorman , Peter Zijlstra , Steven Rostedt , Vincent Guittot References: <675544de-3369-e26e-65ba-3b28fff5c126@gnuweeb.org> From: Dietmar Eggemann In-Reply-To: <675544de-3369-e26e-65ba-3b28fff5c126@gnuweeb.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/04/2022 15:13, Ammar Faizi wrote: > On 4/5/22 7:21 PM, Dietmar Eggemann wrote: >> Tried to recreate the issue but no success so far. I used you config >> file, clang-14 and a Xeon CPU E5-2690 v2 (2 sockets 40 CPUs) with 20 >> two-level cgoupv1 taskgroups '/X/Y' with 'hackbench (10 groups, 40 fds) >> + idling' running in all '/X/Y/'. >> >> What userspace are you running? > > HP Laptop, Intel i7-1165G7, 8 CPUs, with 16 GB of RAM. Ubuntu 21.10. > Just for > daily workstation. Compiling kernel, browsing and coding stuff. Can you check that CFS Bandwidth control (CONFIG_CFS_BANDWIDTH=y) is still not used on Ubuntu desktop 21.10? It shouldn't but I can't verify since I'm still on 20.04 LTS Desktop: $ mount | grep "cgroup2\|\bcpu\b" cgroup2 on /sys/fs/cgroup/unified type cgroup2 (rw,nosuid,nodev,noexec,relatime,nsdelegate) cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpu,cpuacct) CPU controller is still used in cgroupv1. So cgroupv2 can't use it: $ cat /sys/fs/cgroup/unified/cgroup.controllers /* empty */ And there is no cgroupv1 hierarchy under /sys/fs/cgroup/cpu,cpuacct/ . No cpu.cfs_quota_us files with something other than -1. So CFS Bandwidth control is not used. [...]