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=-7.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 DAD2CC56201 for ; Wed, 18 Nov 2020 23:52:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 706EF246BC for ; Wed, 18 Nov 2020 23:52:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="MJOHMPKs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727741AbgKRXv5 (ORCPT ); Wed, 18 Nov 2020 18:51:57 -0500 Received: from m12-14.163.com ([220.181.12.14]:33427 "EHLO m12-14.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727271AbgKRXv5 (ORCPT ); Wed, 18 Nov 2020 18:51:57 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=Date:From:Subject:Message-ID:MIME-Version; bh=9pqaT Qp4Vb5INsN8AW1OxXTjIEtfHbwuFt3hkNTEU2M=; b=MJOHMPKsveQ+/y2u8nfNP QIJfNBjB3e+Ljr/mZeIWHjhS3ExCdXoSWdOP6qfHECp/fpQhzTRPIYeq2o3Le//V bYarg7toNQfh4bes5Cu7c33ous2Z+53ufuuFaC0sxpXdrY8J1Q2ir+PgHQoLh0p5 h9dPkf1nROHE3cRnOk067c= Received: from localhost (unknown [122.194.9.203]) by smtp10 (Coremail) with SMTP id DsCowABXf_sos7VfGZ44Wg--.37073S2; Thu, 19 Nov 2020 07:50:01 +0800 (CST) Date: Thu, 19 Nov 2020 07:50:15 +0800 From: Tao Zhou To: "Guilherme G. Piccoli" Cc: vincent.guittot@linaro.org, bsegall@google.com, dietmar.eggemann@arm.com, juri.lelli@redhat.com, zohooouoto@zoho.com.cn, mgorman@suse.de, mingo@redhat.com, ouwen210@hotmail.com, pauld@redhat.com, peterz@infradead.org, pkondeti@codeaurora.org, rostedt@goodmis.org, Jay Vosburgh , Gavin Guo , halves@canonical.com, nivedita.singhvi@canonical.com, linux-kernel@vger.kernel.org, t1zhou@163.com Subject: Re: [PATCH v3] sched/fair: fix unthrottle_cfs_rq for leaf_cfs_rq list Message-ID: <20201118235015.GB6015@geo.homenetwork> References: <17fc60a3-cc50-7cff-eb46-904c2f0c416e@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <17fc60a3-cc50-7cff-eb46-904c2f0c416e@canonical.com> X-CM-TRANSID: DsCowABXf_sos7VfGZ44Wg--.37073S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7tr18ZF1UXr1DJF1fAr4ruFg_yoW8Wr1fpF 4kWrW3Gr1DGr1xJ3ykGw4Sva4DXws5JrWa93Z5G34rCFWYqr9FvryI939I9FZI9F97KFy0 yFsFva45ta4DAa7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zM_ManUUUUU= X-Originating-IP: [122.194.9.203] X-CM-SenderInfo: vwr2x0rx6rljoofrz/1tbiygngllQHKOCYqgAAsc Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.