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 D26FDC04A68 for ; Wed, 27 Jul 2022 22:05:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234185AbiG0WFs (ORCPT ); Wed, 27 Jul 2022 18:05:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229628AbiG0WFq (ORCPT ); Wed, 27 Jul 2022 18:05:46 -0400 Received: from mail-pj1-x102c.google.com (mail-pj1-x102c.google.com [IPv6:2607:f8b0:4864:20::102c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 283115FAF; Wed, 27 Jul 2022 15:05:45 -0700 (PDT) Received: by mail-pj1-x102c.google.com with SMTP id ha11so290689pjb.2; Wed, 27 Jul 2022 15:05:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:from:to:cc; bh=LiTE1tqkRaXoGmySEYYRcpLO/+mjVSFHJMv7429wZro=; b=NHwA96X568WaIEaeAdyZO0/H9EiUstVUoUzwPvi2DW1XeFPSXJM+pno7z20CNEPdfy jtpUoD/NG77HMfz2SM4Ew7XWm1yx8KoqX+PI7rWzBicwdqH9eDqFHw2hbPV6fOOzZ8Ap uMKQuplFrpNzf5Cb5h/NBlg9o1HDqGzE0Kt/Dwj9q7S2WYHvoSsd2krjCbICCTtH4zt4 P6E8MSKWyMYt4AwrkdxRnTiJLFDggFyKpRxi9r8belvxHq0vSmVEVCjrOVv2hpHD55dY +Oul0/kXpRw8XYWK7OM3ESjaB8h/IKZJICgzzFqdnyU8j2XN04DKgNTmo+Vi/yWLXWn7 aYYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:x-gm-message-state:from:to:cc; bh=LiTE1tqkRaXoGmySEYYRcpLO/+mjVSFHJMv7429wZro=; b=1JqeiBNk7OjM2DZd2d0orKG/rzWHvdRodeAjTerIyLAtGeGaP1VF6FJL1DhICqtLXC 7oKnrW+1CNhM8FqT+sddIK56LA4g+yaJBGae6b53BILWgI0zuD0s21LHnndD6I5lf+ty ocRwAxVKQ3XII9LrZftPniv3Ca9idnJ1GH+41IZcLLNoZWENyMiJqmbb7D3hWvzXvm3T 5LkwYd1GTbXzhWGpSs/zG+1jOI6kpETECaSiUfqajA1isvzee/aS7CtTSFdoPE46sLe/ M9ZSfVhDiPEQRDKP/PBP92Jb/x0lw0lr7KFYxACq/GSjfA+U/0VGgfGsRPcJ/xbTZVvi 9org== X-Gm-Message-State: AJIora/n7oo3M8/GZgSQCYibchwkopVfXsiaMl4b0N/cPc1pdeqhTBVk u7mxgXzUfP3GPMpc2CunuYU= X-Google-Smtp-Source: AGRyM1sOnkApFtvoXih9H6FXYdeOtMGZvB9VSQD6m0DxjYnRs64/cCZfh/dSg2k1v8GKt4MWAe1kgQ== X-Received: by 2002:a17:902:aa89:b0:16b:e514:54d2 with SMTP id d9-20020a170902aa8900b0016be51454d2mr23780612plr.127.1658959544183; Wed, 27 Jul 2022 15:05:44 -0700 (PDT) Received: from localhost ([2620:10d:c090:400::5:5a55]) by smtp.gmail.com with ESMTPSA id f10-20020a170902ce8a00b0016d785ef6d2sm7302739plg.223.2022.07.27.15.05.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 27 Jul 2022 15:05:43 -0700 (PDT) Sender: Tejun Heo Date: Wed, 27 Jul 2022 12:05:41 -1000 From: Tejun Heo To: Peter Zijlstra Cc: Qais Yousef , Xuewen Yan , rafael@kernel.org, viresh.kumar@linaro.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, linux-kernel@vger.kernel.org, ke.wang@unisoc.com, xuewyan@foxmail.com, linux-pm@vger.kernel.org, Waiman Long Subject: Re: [PATCH] sched/schedutil: Fix deadlock between cpuset and cpu hotplug when using schedutil Message-ID: References: <20220705123705.764-1-xuewen.yan@unisoc.com> <20220711174629.uehfmqegcwn2lqzu@wubuntu> <20220712125702.yg4eqbaakvj56k6m@wubuntu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Thu, Jul 28, 2022 at 12:01:35AM +0200, Peter Zijlstra wrote: > On Tue, Jul 12, 2022 at 06:13:46AM -1000, Tejun Heo wrote: > > > But now we're failing user-initiated operations randomly. I have a hard time > > seeing that as an acceptable solution. > > There (sadly) is precedent for that; grep for "cpu_hotplug_disable". Yeah, there's another one in cpu cgroup controller attach path. We should get better at not doing these. Low frequency arbitrary failures are really difficult to handle reliably downstream. Thanks. -- tejun