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=-10.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 B0AEDC6369E for ; Thu, 19 Nov 2020 13:25:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3F76D246CA for ; Thu, 19 Nov 2020 13:25:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="iht9VFEu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727115AbgKSNZT (ORCPT ); Thu, 19 Nov 2020 08:25:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53838 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726474AbgKSNZS (ORCPT ); Thu, 19 Nov 2020 08:25:18 -0500 Received: from mail-lf1-x142.google.com (mail-lf1-x142.google.com [IPv6:2a00:1450:4864:20::142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4504EC0613CF for ; Thu, 19 Nov 2020 05:25:18 -0800 (PST) Received: by mail-lf1-x142.google.com with SMTP id w142so8192664lff.8 for ; Thu, 19 Nov 2020 05:25:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=KLQf36DeOut5/5BOL2GcUQMrMJwzUV5j8KCDhBu2E+k=; b=iht9VFEu0IoOXoakcowuQegaWzvNUB079aNJiHsBjuQGCXqC/IP+4OEEOAHES8o/N3 a4yjIvhvwGK08M6wWpjQ/m/kk1bdfQBGIuCAaiap1PpzVAi2y8tdqics7XCDyV1fzJ6i pQXaXHgZvt/F2P+14xTwdEwULl1VRCF4gDMBzwKAOYbeY2yWB7xdVz5dooqRtKpkvZyY oZw6kBUfP9jSKkfNf7Xiax4jy7VbHldPSz3MSEYkoBBzBUsvsu6G+RjmTrrp+g27YtUN OGEK5KD41ujZfWmTuWQSSPRgtq6kP+vX7mm5+XtD9La8qHGYyzHRnF12/fhCcmYU+JBG DLyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=KLQf36DeOut5/5BOL2GcUQMrMJwzUV5j8KCDhBu2E+k=; b=N6ACwrurMmUNVcVaKR4GcToKW/7fjaEZ8FpbTpX2jBnQqDYENmsNizOH1uwc98n6ne zhplPn7wsccUiCrerFC3OuCqMjEDrBdohAu0Fx73ezdlaQbSPi0wH/2mA9zAqpIB0Zkq 0PPlAXrTIUqQxUeq+t4cfddR8scMOaxzBM5VT1AJmQWPvU386odT2Mtee8ulBz0MpJ89 J7tYRd6WMz2XM+YaPxMskxVS1A+S+pKtRKd4fYLTlMr2ChYyrHT6p9Q+4wnmogpjKhgN GOTQ2RN3W290/+dvTi5NkzjR1yL+u/zqkXCeOidzetiFAcxiPOXkWye2pJe+BtPqaJbb zfoQ== X-Gm-Message-State: AOAM533c7AhCvNHm+bzobfDU8UtMKCyQs8eo/UewY3R5dynYG08N6+FU 6N/tB662mFMo9Dl0RFda+pJcVsoXVeX7MhG2fHS34Q== X-Google-Smtp-Source: ABdhPJyOzK0Kea8uVCED1TnJFYe2hbyhH6rNZcb5m72i+hCtQQ80j7LJ2WsPyw1/5uCdaulSo3B7yoofIKqFlgXyvfE= X-Received: by 2002:a19:a0c:: with SMTP id 12mr6292839lfk.568.1605792316677; Thu, 19 Nov 2020 05:25:16 -0800 (PST) MIME-Version: 1.0 References: <17fc60a3-cc50-7cff-eb46-904c2f0c416e@canonical.com> <20201118235015.GB6015@geo.homenetwork> <20201119003319.GA6805@geo.homenetwork> <7c9462c9-8908-8592-0727-9117d4173724@canonical.com> In-Reply-To: <7c9462c9-8908-8592-0727-9117d4173724@canonical.com> From: Vincent Guittot Date: Thu, 19 Nov 2020 14:25:05 +0100 Message-ID: Subject: Re: [PATCH v3] sched/fair: fix unthrottle_cfs_rq for leaf_cfs_rq list To: "Guilherme G. Piccoli" Cc: Tao Zhou , "gregkh@linuxfoundation.org" , Sasha Levin , SeongJae Park , Ben Segall , Dietmar Eggemann , Juri Lelli , Tao Zhou , Mel Gorman , Ingo Molnar , Tao Zhou , Phil Auld , Peter Zijlstra , Pavan Kondeti , Steven Rostedt , Jay Vosburgh , Gavin Guo , halves@canonical.com, nivedita.singhvi@canonical.com, linux-kernel , "# v4 . 16+" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 19 Nov 2020 at 12:36, Guilherme G. Piccoli wrote: > > > > On 19/11/2020 05:36, Vincent Guittot wrote: > > On Thu, 19 Nov 2020 at 01:36, Tao Zhou wrote: > >> > >> On Thu, Nov 19, 2020 at 07:50:15AM +0800, Tao Zhou wrote: > >>> On Wed, Nov 18, 2020 at 07:56:38PM -0300, Guilherme G. Piccoli wrote: > >>>> Hi Vincent (and all CCed), I'm sorry to ping about such "old" patch, but > >>>> we experienced a similar condition to what this patch addresses; it's an > >>>> older kernel (4.15.x) but when suggesting the users to move to an > >>>> updated 5.4.x kernel, we noticed that this patch is not there, although > >>>> similar ones are (like [0] and [1]). > >>>> > >>>> So, I'd like to ask if there's any particular reason to not backport > >>>> this fix to stable kernels, specially the longterm 5.4. The main reason > >>>> behind the question is that the code is very complex for non-experienced > >>>> scheduler developers, and I'm afraid in suggesting such backport to 5.4 > >>>> and introduce complex-to-debug issues. > >>>> > >>>> Let me know your thoughts Vincent (and all CCed), thanks in advance. > >>>> Cheers, > >>>> > >>>> > >>>> Guilherme > >>>> > >>>> > >>>> P.S. For those that deleted this thread from the email client, here's a > >>>> link: > >>>> https://lore.kernel.org/lkml/20200513135528.4742-1-vincent.guittot@linaro.org/ > >>>> > >>>> > >>>> [0] > >>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fe61468b2cb > >>>> > >>>> [1] > >>>> https://lore.kernel.org/lkml/20200506141821.GA9773@lorien.usersys.redhat.com/ > >>>> <- great thread BTW! > >>> > >>> 'sched/fair: Fix unthrottle_cfs_rq() for leaf_cfs_rq list" failed to apply to > >>> 5.4-stable tree' > >>> > >>> You could check above. But I do not have the link about this. Can't search it > >>> on LKML web: https://lore.kernel.org/lkml/ > >>> > >>> BTW: 'ouwen210@hotmail.com' and 'zohooouoto@zoho.com.cn' all is myself. > >>> > >>> Sorry for the confusing.. > >>> > >>> Thanks. > >> > >> Sorry again. I forget something. It is in the stable. > >> > >> Here it is: > >> > >> https://lore.kernel.org/stable/159041776924279@kroah.com/ > > > > I think it has never been applied to stable. > > As you mentioned, the backport has been sent : > > https://lore.kernel.org/stable/20200525172709.GB7427@vingu-book/ > > > > I received another emailed in September and pointed out to the > > backport : https://www.spinics.net/lists/stable/msg410445.html > > > > > >> > > Thanks a lot Tao and Vincent! Nice to know that you already worked the > backport, gives much more confidence when the author does that heheh > > So, this should go to stable 5.4.y, but not 4.19.y IIUC? Yeah. they should be backported up to v5.1 but not earlier Regards, Vincent > Cheers, > > > Guilherme