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,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 9E49FC433E0 for ; Wed, 1 Jul 2020 10:05:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 876D02073E for ; Wed, 1 Jul 2020 10:05:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729795AbgGAKFH (ORCPT ); Wed, 1 Jul 2020 06:05:07 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:20446 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729057AbgGAKFF (ORCPT ); Wed, 1 Jul 2020 06:05:05 -0400 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 061A3D4U112370; Wed, 1 Jul 2020 06:04:50 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 320pjt3us7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 01 Jul 2020 06:04:50 -0400 Received: from m0098416.ppops.net (m0098416.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 061A3D0h112394; Wed, 1 Jul 2020 06:04:49 -0400 Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0b-001b2d01.pphosted.com with ESMTP id 320pjt3ur9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 01 Jul 2020 06:04:49 -0400 Received: from pps.filterd (ppma06ams.nl.ibm.com [127.0.0.1]) by ppma06ams.nl.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 0619qH6v009168; Wed, 1 Jul 2020 10:04:47 GMT Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by ppma06ams.nl.ibm.com with ESMTP id 31wwch4dq2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 01 Jul 2020 10:04:47 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 061A4jmi26673334 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 1 Jul 2020 10:04:45 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7B1615205A; Wed, 1 Jul 2020 10:04:45 +0000 (GMT) Received: from linux.vnet.ibm.com (unknown [9.126.150.29]) by d06av21.portsmouth.uk.ibm.com (Postfix) with SMTP id D50F65204E; Wed, 1 Jul 2020 10:04:42 +0000 (GMT) Date: Wed, 1 Jul 2020 15:34:42 +0530 From: Srikar Dronamraju To: Michal Hocko Cc: Andrew Morton , linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mel Gorman , Vlastimil Babka , "Kirill A. Shutemov" , Christopher Lameter , 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: <20200701100442.GB17918@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> <20200701084200.GN2369@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20200701084200.GN2369@dhcp22.suse.cz> 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=2020-07-01_04:2020-07-01,2020-07-01 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=999 clxscore=1015 suspectscore=0 mlxscore=0 adultscore=0 impostorscore=0 cotscore=-2147483648 spamscore=0 lowpriorityscore=0 priorityscore=1501 malwarescore=0 bulkscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2007010069 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Michal Hocko [2020-07-01 10:42:00]: > > > > > 2. Also existence of dummy node also leads to inconsistent information. The > > number of online nodes is inconsistent with the information in the > > device-tree and resource-dump > > > > 3. When the dummy node is present, single node non-Numa systems end up showing > > up as NUMA systems and numa_balancing gets enabled. This will mean we take > > the hit from the unnecessary numa hinting faults. > > I have to say that I dislike the node online/offline state and directly > exporting that to the userspace. Users should only care whether the node > has memory/cpus. Numa nodes can be online without any memory. Just > offline all the present memory blocks but do not physically hot remove > them and you are in the same situation. If users are confused by an > output of tools like numactl -H then those could be updated and hide > nodes without any memory&cpus. > > The autonuma problem sounds interesting but again this patch doesn't > really solve the underlying problem because I strongly suspect that the > problem is still there when a numa node gets all its memory offline as > mentioned above. > > While I completely agree that making node 0 special is wrong, I have > still hard time to review this very simply looking patch because all the > numa initialization is so spread around that this might just blow up > at unexpected places. IIRC we have discussed testing in the previous > version and David has provided a way to emulate these configurations > on x86. Did you manage to use those instruction for additional testing > on other than ppc architectures? > I have tried all the steps that David mentioned and reported back at https://lore.kernel.org/lkml/20200511174731.GD1961@linux.vnet.ibm.com/t/#u As a summary, David's steps are still not creating a memoryless/cpuless on x86 VM. I have tried booting with Numa/non-numa on all the x86 machines that I could get to. -- Thanks and Regards Srikar Dronamraju