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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 EC08AC352A3 for ; Tue, 11 Feb 2020 08:17:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 08F2920714 for ; Tue, 11 Feb 2020 08:17:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727880AbgBKIRj (ORCPT ); Tue, 11 Feb 2020 03:17:39 -0500 Received: from out30-131.freemail.mail.aliyun.com ([115.124.30.131]:37265 "EHLO out30-131.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727687AbgBKIRj (ORCPT ); Tue, 11 Feb 2020 03:17:39 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07417;MF=yun.wang@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0TpgaLzl_1581409054; Received: from testdeMacBook-Pro.local(mailfrom:yun.wang@linux.alibaba.com fp:SMTPD_---0TpgaLzl_1581409054) by smtp.aliyun-inc.com(127.0.0.1); Tue, 11 Feb 2020 16:17:35 +0800 To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , "open list:SCHEDULER" From: =?UTF-8?B?546L6LSH?= Subject: [RFC] why can't dynamic isolation just like the static way Message-ID: Date: Tue, 11 Feb 2020 16:17:34 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, folks We are dealing with isolcpus these days and try to do the isolation dynamically. The kernel doc lead us into the cpuset.sched_load_balance, it's fine to achieve the dynamic isolation with it, however we got problem with the systemd stuff. It's keeping create cgroup with sched_load_balance enabled on default, while the cpus are overlapped with the isolated ones, which lead into sched domain rebuild and these cpus become non-isolated. We're just looking forward an easy way to dynamic isolate some cpus, just like the isolation parameter, but sched_load_balance forcing us to dealing with the management of cgroups, we really don't get the point in here... Why do we have to mix the isolation with cgroups? Why not just provide a proc entry to read cpumask and rebuild the domains? Please let us know if there is any good reason to make the dynamic isolation in that way, appreciated in advance :-) Regards, Michael Wang