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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A8A0EC433E3 for ; Tue, 18 Aug 2020 07:37:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6CA85207FB for ; Tue, 18 Aug 2020 07:37:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726541AbgHRHhP (ORCPT ); Tue, 18 Aug 2020 03:37:15 -0400 Received: from mx2.suse.de ([195.135.220.15]:48304 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726043AbgHRHhO (ORCPT ); Tue, 18 Aug 2020 03:37:14 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 50B33ABCC; Tue, 18 Aug 2020 07:37:38 +0000 (UTC) Date: Tue, 18 Aug 2020 09:37:12 +0200 From: Michal Hocko To: David Hildenbrand Cc: Srikar Dronamraju , Andrew Morton , Michal Such?nek , Gautham R Shenoy , Linus Torvalds , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Satheesh Rajendran , Mel Gorman , "Kirill A. Shutemov" , linuxppc-dev@lists.ozlabs.org, Christopher Lameter , Vlastimil Babka , Andi Kleen , "Aneesh Kumar K.V" Subject: Re: [PATCH v5 3/3] mm/page_alloc: Keep memoryless cpuless node 0 offline Message-ID: <20200818073712.GK28270@dhcp22.suse.cz> References: <0468f965-8762-76a3-93de-3987cf859927@redhat.com> <12945273-d788-710d-e8d7-974966529c7d@redhat.com> <20200701122110.GT2369@dhcp22.suse.cz> <20200703091001.GJ21462@kitsune.suse.cz> <20200703092414.GR18446@dhcp22.suse.cz> <20200703105944.GS18446@dhcp22.suse.cz> <20200703125823.GA26243@linux.vnet.ibm.com> <20200806213211.6a6a56037fe771836e5abbe9@linux-foundation.org> <20200812060101.GB10992@linux.vnet.ibm.com> <13a85e52-5caa-24a8-7169-3992b1ad262a@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <13a85e52-5caa-24a8-7169-3992b1ad262a@redhat.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 18-08-20 09:32:52, David Hildenbrand wrote: > On 12.08.20 08:01, Srikar Dronamraju wrote: > > Hi Andrew, Michal, David > > > > * Andrew Morton [2020-08-06 21:32:11]: > > > >> On Fri, 3 Jul 2020 18:28:23 +0530 Srikar Dronamraju wrote: > >> > >>>> The memory hotplug changes that somehow because you can hotremove numa > >>>> nodes and therefore make the nodemask sparse but that is not a common > >>>> case. I am not sure what would happen if a completely new node was added > >>>> and its corresponding node was already used by the renumbered one > >>>> though. It would likely conflate the two I am afraid. But I am not sure > >>>> this is really possible with x86 and a lack of a bug report would > >>>> suggest that nobody is doing that at least. > >>>> > >>> > >>> JFYI, > >>> Satheesh copied in this mailchain had opened a bug a year on crash with vcpu > >>> hotplug on memoryless node. > >>> > >>> https://bugzilla.kernel.org/show_bug.cgi?id=202187 > >> > >> So... do we merge this patch or not? Seems that the overall view is > >> "risky but nobody is likely to do anything better any time soon"? > > > > Can we decide on this one way or the other? > > Hmm, not sure who's the person to decide. I tend to prefer doing the > node renaming, handling this in ppc code; Agreed. That would be a safer option. -- Michal Hocko SUSE Labs