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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 A5344C433DF for ; Fri, 7 Aug 2020 10:05:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8323620855 for ; Fri, 7 Aug 2020 10:05:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728228AbgHGKFC (ORCPT ); Fri, 7 Aug 2020 06:05:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:49402 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727820AbgHGKFB (ORCPT ); Fri, 7 Aug 2020 06:05:01 -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 625ADAC19; Fri, 7 Aug 2020 10:05:17 +0000 (UTC) Date: Fri, 7 Aug 2020 12:04:58 +0200 From: Michal =?iso-8859-1?Q?Such=E1nek?= To: David Hildenbrand Cc: Andrew Morton , Srikar Dronamraju , Gautham R Shenoy , Andi Kleen , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Michal Hocko , linux-mm@kvack.org, Satheesh Rajendran , Mel Gorman , "Kirill A. Shutemov" , Christopher Lameter , Linus Torvalds , Vlastimil Babka Subject: Re: [PATCH v5 3/3] mm/page_alloc: Keep memoryless cpuless node 0 offline Message-ID: <20200807100458.GI32107@kitsune.suse.cz> References: <20200701110145.GC17918@linux.vnet.ibm.com> <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> <5688b358-36bc-ccf0-d24b-a65375a9f3c3@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5688b358-36bc-ccf0-d24b-a65375a9f3c3@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 07, 2020 at 08:58:09AM +0200, David Hildenbrand wrote: > On 07.08.20 06:32, Andrew Morton wrote: > > 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"? > > I recall the issue Michal saw was "fix powerpc" vs. "break other > architectures". @Michal how should we proceed? At least x86-64 won't be > affected IIUC. There is a patch to introduce the node remapping on ppc as well which should eliminate the empty node 0. https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20200731111916.243569-1-aneesh.kumar@linux.ibm.com/ Thanks Michal