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 C0B52C433DF for ; Tue, 18 Aug 2020 07:37:15 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8A96A2076E for ; Tue, 18 Aug 2020 07:37:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8A96A2076E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 29FE78D0005; Tue, 18 Aug 2020 03:37:15 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 250F88D0003; Tue, 18 Aug 2020 03:37:15 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 166E48D0005; Tue, 18 Aug 2020 03:37:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0023.hostedemail.com [216.40.44.23]) by kanga.kvack.org (Postfix) with ESMTP id 01CAF8D0003 for ; Tue, 18 Aug 2020 03:37:14 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id ACD76180AD830 for ; Tue, 18 Aug 2020 07:37:14 +0000 (UTC) X-FDA: 77162883588.04.rose94_08128592701d Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin04.hostedemail.com (Postfix) with ESMTP id 867E9800621C for ; Tue, 18 Aug 2020 07:37:14 +0000 (UTC) X-HE-Tag: rose94_08128592701d X-Filterd-Recvd-Size: 3328 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf47.hostedemail.com (Postfix) with ESMTP for ; Tue, 18 Aug 2020 07:37:14 +0000 (UTC) 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> X-Rspamd-Queue-Id: 867E9800621C X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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