From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754585AbcESOrz (ORCPT ); Thu, 19 May 2016 10:47:55 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:57783 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754321AbcESOry (ORCPT ); Thu, 19 May 2016 10:47:54 -0400 Date: Thu, 19 May 2016 16:46:57 +0200 From: Peter Zijlstra To: Zhu Guihua Cc: cl@linux.com, tj@kernel.org, mika.j.penttila@gmail.com, mingo@redhat.com, akpm@linux-foundation.org, rjw@rjwysocki.net, hpa@zytor.com, yasu.isimatu@gmail.com, isimatu.yasuaki@jp.fujitsu.com, kamezawa.hiroyu@jp.fujitsu.com, izumi.taku@jp.fujitsu.com, gongzhaogang@inspur.com, len.brown@intel.com, lenb@kernel.org, tglx@linutronix.de, chen.tang@easystack.cn, rafael@kernel.org, x86@kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v7 0/5] Make cpuid <-> nodeid mapping persistent Message-ID: <20160519144657.GK3206@twins.programming.kicks-ass.net> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 19, 2016 at 06:39:41PM +0800, Zhu Guihua wrote: > [Problem] > > cpuid <-> nodeid mapping is firstly established at boot time. And workqueue caches > the mapping in wq_numa_possible_cpumask in wq_numa_init() at boot time. > > When doing node online/offline, cpuid <-> nodeid mapping is established/destroyed, > which means, cpuid <-> nodeid mapping will change if node hotplug happens. But > workqueue does not update wq_numa_possible_cpumask. So why are you not fixing up wq_numa_possible_cpumask instead? That seems the far easier solution. Do all the other archs that support NUMA and HOTPLUG have the mapping stable, or will you now go fix each and every one of them?