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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 C62FDC432C1 for ; Wed, 25 Sep 2019 09:14:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A135D20673 for ; Wed, 25 Sep 2019 09:14:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389183AbfIYJOm (ORCPT ); Wed, 25 Sep 2019 05:14:42 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:2718 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2388828AbfIYJOb (ORCPT ); Wed, 25 Sep 2019 05:14:31 -0400 Received: from DGGEMS414-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 9C859387E7EFF1887A06; Wed, 25 Sep 2019 17:14:25 +0800 (CST) Received: from [127.0.0.1] (10.74.191.121) by DGGEMS414-HUB.china.huawei.com (10.3.19.214) with Microsoft SMTP Server id 14.3.439.0; Wed, 25 Sep 2019 17:14:21 +0800 Subject: Re: [PATCH v6] numa: make node_to_cpumask_map() NUMA_NO_NODE aware To: Michal Hocko , Peter Zijlstra CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , References: <20190923203410.GI2369@hirez.programming.kicks-ass.net> <20190924074751.GB23050@dhcp22.suse.cz> <20190924091714.GJ2369@hirez.programming.kicks-ass.net> <20190924105622.GH23050@dhcp22.suse.cz> <20190924112349.GJ2332@hirez.programming.kicks-ass.net> <20190924115401.GM23050@dhcp22.suse.cz> <20190924120943.GP2349@hirez.programming.kicks-ass.net> <20190924122500.GP23050@dhcp22.suse.cz> <20190924124325.GQ2349@hirez.programming.kicks-ass.net> <20190924125936.GR2349@hirez.programming.kicks-ass.net> <20190924131939.GS23050@dhcp22.suse.cz> From: Yunsheng Lin Message-ID: <1adcbe68-6753-3497-48a0-cc84ac503372@huawei.com> Date: Wed, 25 Sep 2019 17:14:20 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <20190924131939.GS23050@dhcp22.suse.cz> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.74.191.121] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/9/24 21:19, Michal Hocko wrote: > On Tue 24-09-19 14:59:36, Peter Zijlstra wrote: >> On Tue, Sep 24, 2019 at 02:43:25PM +0200, Peter Zijlstra wrote: >>> On Tue, Sep 24, 2019 at 02:25:00PM +0200, Michal Hocko wrote: >>>> On Tue 24-09-19 14:09:43, Peter Zijlstra wrote: >>> >>>>> We can push back and say we don't respect the specification because it >>>>> is batshit insane ;-) >>>> >>>> Here is my fingers crossed. >>>> >>>> [...] >>>> >>>>> Now granted; there's a number of virtual devices that really don't have >>>>> a node affinity, but then, those are not hurt by forcing them onto a >>>>> random node, they really don't do anything. Like: >>>> >>>> Do you really consider a random node a better fix than simply living >>>> with a more robust NUMA_NO_NODE which tells the actual state? Page >>>> allocator would effectivelly use the local node in that case. Any code >>>> using the cpumask will know that any of the online cpus are usable. >>> >>> For the pmu devices? Yes, those 'devices' aren't actually used for >>> anything other than sysfs entries. >>> >>> Nothing else uses the struct device. >> >> The below would get rid of the PMU and workqueue warnings with no >> side-effects (the device isn't used for anything except sysfs). > > Hardcoding to 0 is simply wrong, if the node0 is cpuless for example... Hi, Peter & Michal >From the discussion above, It seems making the node_to_cpumask_map() NUMA_NO_NODE aware is the most feasible way to move forwad. Any suggestion? >