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=-6.1 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 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 7ADE3C433F5 for ; Fri, 3 Sep 2021 14:44:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5933E610E5 for ; Fri, 3 Sep 2021 14:44:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349113AbhICOpC (ORCPT ); Fri, 3 Sep 2021 10:45:02 -0400 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:50565 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349502AbhICOpC (ORCPT ); Fri, 3 Sep 2021 10:45:02 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=haoxu@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0Un6xNvp_1630680239; Received: from B-25KNML85-0107.local(mailfrom:haoxu@linux.alibaba.com fp:SMTPD_---0Un6xNvp_1630680239) by smtp.aliyun-inc.com(127.0.0.1); Fri, 03 Sep 2021 22:43:59 +0800 Subject: Re: [PATCH v4 0/2] refactor sqthread cpu binding logic To: =?UTF-8?Q?Michal_Koutn=c3=bd?= Cc: Jens Axboe , Zefan Li , Tejun Heo , Johannes Weiner , Pavel Begunkov , io-uring@vger.kernel.org, cgroups@vger.kernel.org, Joseph Qi References: <20210901124322.164238-1-haoxu@linux.alibaba.com> <20210902164808.GA10014@blackbody.suse.cz> From: Hao Xu Message-ID: Date: Fri, 3 Sep 2021 22:43:59 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20210902164808.GA10014@blackbody.suse.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org 在 2021/9/3 上午12:48, Michal Koutný 写道: > Hello Hao. > > On Wed, Sep 01, 2021 at 08:43:20PM +0800, Hao Xu wrote: >> This patchset is to enhance sqthread cpu binding logic, we didn't >> consider cgroup setting before. In container environment, theoretically >> sqthread is in its container's task group, it shouldn't occupy cpu out >> of its container. > > I see in the discussions that there's struggle to make > set_cpus_allowed_ptr() do what's intended under the given constraints. > > IIUC, set_cpus_allowed_ptr() is conventionally used for kernel threads > [1]. But does the sqthread fall into this category? You want to have it > _directly_ associated with a container and its cgroups. It looks to me sqthread is in it's creator's task group, so it is like a userspace thread from this perspective. When it comes to container environemt sqthread naturely belongs to a container which also contains its creator And it has same cgroup setting with it's creator by default. > more like a userspace thread (from this perspective, not literally). Or > is there a different intention? > > It seems to me that reusing the sched_setaffinity() (with all its > checks and race pains/solutions) would be a more universal approach. > (I don't mean calling sched_setaffinity() directly, some parts would > need to be factored separately to this end.) WDYT? > > > Regards, > Michal > > [1] Not only spending their life in kernel but providing some > delocalized kernel service. >