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=-2.5 required=3.0 tests=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 3CBC6C433E0 for ; Tue, 30 Jun 2020 04:01:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C5000206BE for ; Tue, 30 Jun 2020 04:01:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C5000206BE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.vnet.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 572C26B009B; Tue, 30 Jun 2020 00:01:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 522E76B009E; Tue, 30 Jun 2020 00:01:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 413286B009F; Tue, 30 Jun 2020 00:01:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0250.hostedemail.com [216.40.44.250]) by kanga.kvack.org (Postfix) with ESMTP id 2722D6B009B for ; Tue, 30 Jun 2020 00:01:40 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id AF7E21EE6 for ; Tue, 30 Jun 2020 04:01:39 +0000 (UTC) X-FDA: 76984529118.08.spy86_180ccac26e74 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin08.hostedemail.com (Postfix) with ESMTP id 87D2C1819E764 for ; Tue, 30 Jun 2020 04:01:39 +0000 (UTC) X-HE-Tag: spy86_180ccac26e74 X-Filterd-Recvd-Size: 5225 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by imf29.hostedemail.com (Postfix) with ESMTP for ; Tue, 30 Jun 2020 04:01:38 +0000 (UTC) Received: from pps.filterd (m0127361.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 05U3eSuk060397; Tue, 30 Jun 2020 00:01:34 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 31xkqk8g41-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 30 Jun 2020 00:01:34 -0400 Received: from m0127361.ppops.net (m0127361.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 05U32Rxv060490; Tue, 30 Jun 2020 00:01:33 -0400 Received: from ppma04fra.de.ibm.com (6a.4a.5195.ip4.static.sl-reverse.com [149.81.74.106]) by mx0a-001b2d01.pphosted.com with ESMTP id 31xkqk8g3b-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 30 Jun 2020 00:01:33 -0400 Received: from pps.filterd (ppma04fra.de.ibm.com [127.0.0.1]) by ppma04fra.de.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 05U41V2e009727; Tue, 30 Jun 2020 04:01:31 GMT Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by ppma04fra.de.ibm.com with ESMTP id 31wwr81fqb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 30 Jun 2020 04:01:31 +0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 05U41SpL53346418 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 30 Jun 2020 04:01:28 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BD097A4055; Tue, 30 Jun 2020 04:01:28 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 52D9AA4057; Tue, 30 Jun 2020 04:01:26 +0000 (GMT) Received: from linux.vnet.ibm.com (unknown [9.126.150.29]) by d06av23.portsmouth.uk.ibm.com (Postfix) with SMTP; Tue, 30 Jun 2020 04:01:26 +0000 (GMT) Date: Tue, 30 Jun 2020 09:31:25 +0530 From: Srikar Dronamraju To: Christopher Lameter Cc: Andrew Morton , linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Michal Hocko , Mel Gorman , Vlastimil Babka , "Kirill A. Shutemov" , Michael Ellerman , Linus Torvalds , Gautham R Shenoy , Satheesh Rajendran , David Hildenbrand Subject: Re: [PATCH v5 3/3] mm/page_alloc: Keep memoryless cpuless node 0 offline Message-ID: <20200630040125.GA31617@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20200624092846.9194-1-srikar@linux.vnet.ibm.com> <20200624092846.9194-4-srikar@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-06-29_21:2020-06-29,2020-06-29 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=999 bulkscore=0 mlxscore=0 adultscore=0 clxscore=1015 phishscore=0 priorityscore=1501 malwarescore=0 lowpriorityscore=0 suspectscore=0 cotscore=-2147483648 spamscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006300021 X-Rspamd-Queue-Id: 87D2C1819E764 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 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: * Christopher Lameter [2020-06-29 14:58:40]: > On Wed, 24 Jun 2020, Srikar Dronamraju wrote: > > > Currently Linux kernel with CONFIG_NUMA on a system with multiple > > possible nodes, marks node 0 as online at boot. However in practice, > > there are systems which have node 0 as memoryless and cpuless. > > Maybe add something to explain why you are not simply mapping the > existing memory to NUMA node 0 which is after all just a numbering scheme > used by the kernel and can be used arbitrarily? > I thought Michal Hocko already gave a clear picture on why mapping is a bad idea. https://lore.kernel.org/lkml/20200316085425.GB11482@dhcp22.suse.cz/t/#u Are you suggesting that we add that as part of the changelog? > This could be seen more as a bug in the arch code during the setup of NUMA > nodes. The two nodes are created by the firmwware / bootstrap code after > all. Just do not do it? > - The arch/setup code in powerpc is not onlining these nodes. - Later on cpus/memory in node 0 can be onlined. - Firmware in this case Phyp is an independent code by itself. -- Thanks and Regards Srikar Dronamraju