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=-0.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT 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 54596C43387 for ; Sun, 30 Dec 2018 12:04:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1C59B20861 for ; Sun, 30 Dec 2018 12:04:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546171482; bh=pR9LxT80TjmMDt19R2Psf6JxjI6f6zCq/OEOw945w54=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=xV10lVFs5BX3D9TD2LMaGfatIKR1rCH9D6+MKE3I5Vv7pWtk53aKtMj80N1dQZMKD vRu+cCQBGg88Pzc3hMRiniR/NLwGJAz3tMchR63OitmjJdq5nk4K4DSc1u8olmIoZP yMi+1SqMgxOtDha5csjY1/eGH3TWuQt7tIU4TlPs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726249AbeL3MEk (ORCPT ); Sun, 30 Dec 2018 07:04:40 -0500 Received: from mail-wm1-f65.google.com ([209.85.128.65]:35469 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725971AbeL3MEk (ORCPT ); Sun, 30 Dec 2018 07:04:40 -0500 Received: by mail-wm1-f65.google.com with SMTP id t200so10827531wmt.0 for ; Sun, 30 Dec 2018 04:04:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=tNijJ/aFlw2SFIH/qJFXPhCMT9WEtXSQm7oLvhbjg8A=; b=vK+B4ZGbw47KK2gogBw9Xqpj3OabLicAKar329E/HbPaBPCYQwYGbhQG4UspA6DR0O 9jbnvaBSX50E44uTMIxxCATDL44sjGCaoCo6MH0Nbo7f869JQZBpROqMhvej1Z7FGV6y FfJwF+OSz7ksTNSG7XoI0pYbhDxXGjJm0VGJLOWlni/hydhOJsHExq3OXukzjk1Krhra jzs9eF/jSWGE5D9cZ3vYIUynrtb0K2PMF89whsncACAB5U0LE9FsLUhng0oqfkFTK9mh LWp8PHzFszVDmgmAjrkk98Opr8AcjQ2NVY/lMVOwrfnz9YJZVqPsXXFBFpIrtOVmu7/3 cAsA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=tNijJ/aFlw2SFIH/qJFXPhCMT9WEtXSQm7oLvhbjg8A=; b=Oo3Z69ckXR/uWjzBV20DES1MW0lqGjT/ZbY6vO1IZO0ZDY3GAYocYKgj0T+0oxannQ vUpdF6ZO5voEd0F/IbJt02+xOnR+f8tsR07/cX3f3s4skZ4KPlPIDeqJc0XzQ+PTQVYA EYSOKchGLamEs0KtqyFt+WTS4ZOYh1peUX6yEQTf2FM6VONbX370m7Tpy5QY+bPWxGCd txCDbwvOXO8rq0UIULEwBllvslcKPaJKluGIyq6dAU+D8szpsLp/MdfOKC+EHgKcAz+k S6DAAWAFDMfarJbA9zW7Awc+66qvXqqI2vvcL4XzROBewcIn6Yf4NqXi07sywTvNPBuz CfWw== X-Gm-Message-State: AJcUukdlOXajgfo+0W/vc5yXBfeY5GXynfMwdGNbRJwUBFKSfom3PBVx aL7vviaywocV/WhmaMyVpOY= X-Google-Smtp-Source: ALg8bN7gFe1Chlx6buqxWxF+81Dbjra1ttD4pl9dxSaRMky+dWcNlErikG0l5FsBGhZw3KoAule2Zg== X-Received: by 2002:a1c:8d53:: with SMTP id p80mr16295606wmd.68.1546171478787; Sun, 30 Dec 2018 04:04:38 -0800 (PST) Received: from gmail.com (2E8B0CD5.catv.pool.telekom.hu. [46.139.12.213]) by smtp.gmail.com with ESMTPSA id j129sm27732783wmb.39.2018.12.30.04.04.37 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sun, 30 Dec 2018 04:04:38 -0800 (PST) Date: Sun, 30 Dec 2018 13:04:35 +0100 From: Ingo Molnar To: Vincent Guittot Cc: Xie XiuQi , Ingo Molnar , Peter Zijlstra , xiezhipeng1@huawei.com, huawei.libin@huawei.com, linux-kernel , Linus Torvalds , Tejun Heo , Peter Zijlstra Subject: Re: [PATCH] sched: fix infinity loop in update_blocked_averages Message-ID: <20181230120435.GA17231@gmail.com> References: <1545879866-27809-1-git-send-email-xiexiuqi@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Vincent Guittot wrote: > > Reported-by: Zhipeng Xie > > Cc: Bin Li > > Cc: [4.10+] > > Fixes: 9c2791f936ef (sched/fair: Fix hierarchical order in rq->leaf_cfs_rq_list) > > If it only happens in update_blocked_averages(), the del leaf has been added by: > a9e7f6544b9c (sched/fair: Fix O(nr_cgroups) in load balance path) So I think until we are confident in the proposed fixes, how about applying Linus's patch that reverts a9e7f6544b9c and simplifies the list manipulation? That way we can re-introduce the O(nr_cgroups) optimization without pressure. I'll prepare a commit for sched/urgent that does this, please holler if any of you disagrees! Thanks, Ingo