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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 6C34AC433E0 for ; Fri, 3 Jul 2020 12:59:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A87C20BED for ; Fri, 3 Jul 2020 12:59:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726418AbgGCM7o (ORCPT ); Fri, 3 Jul 2020 08:59:44 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:2704 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726074AbgGCM7n (ORCPT ); Fri, 3 Jul 2020 08:59:43 -0400 Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 063CUb5E062981; Fri, 3 Jul 2020 08:58:31 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 321cve9ke5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 03 Jul 2020 08:58:30 -0400 Received: from m0098420.ppops.net (m0098420.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 063CWM5N068303; Fri, 3 Jul 2020 08:58:30 -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 321cve9kdg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 03 Jul 2020 08:58:30 -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 063CkiGd024370; Fri, 3 Jul 2020 12:58:28 GMT Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by ppma06ams.nl.ibm.com with ESMTP id 31wwch6tw9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 03 Jul 2020 12:58:28 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 063CwQNW63176796 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 3 Jul 2020 12:58:26 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 73BE052051; Fri, 3 Jul 2020 12:58:26 +0000 (GMT) Received: from linux.vnet.ibm.com (unknown [9.126.150.29]) by d06av21.portsmouth.uk.ibm.com (Postfix) with SMTP id DDCCA5204E; Fri, 3 Jul 2020 12:58:23 +0000 (GMT) Date: Fri, 3 Jul 2020 18:28:23 +0530 From: Srikar Dronamraju To: Michal Hocko Cc: Michal Such?nek , David Hildenbrand , Gautham R Shenoy , Linus Torvalds , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Satheesh Rajendran , Mel Gorman , "Kirill A. Shutemov" , Andrew Morton , linuxppc-dev@lists.ozlabs.org, Christopher Lameter , Vlastimil Babka , Andi Kleen Subject: Re: [PATCH v5 3/3] mm/page_alloc: Keep memoryless cpuless node 0 offline Message-ID: <20200703125823.GA26243@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20200701084200.GN2369@dhcp22.suse.cz> <20200701100442.GB17918@linux.vnet.ibm.com> <184102af-ecf2-c834-db46-173ab2e66f51@redhat.com> <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> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20200703105944.GS18446@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=2020-07-03_06:2020-07-02,2020-07-03 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=999 priorityscore=1501 spamscore=0 suspectscore=0 phishscore=0 clxscore=1011 bulkscore=0 malwarescore=0 adultscore=0 mlxscore=0 cotscore=-2147483648 lowpriorityscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2007030086 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Michal Hocko [2020-07-03 12:59:44]: > > Honestly, I do not have any idea. I've traced it down to > > Author: Andi Kleen > > Date: Tue Jan 11 15:35:48 2005 -0800 > > > > [PATCH] x86_64: Fix ACPI SRAT NUMA parsing > > > > Fix fallout from the recent nodemask_t changes. The node ids assigned > > in the SRAT parser were off by one. > > > > I added a new first_unset_node() function to nodemask.h to allocate > > IDs sanely. > > > > Signed-off-by: Andi Kleen > > Signed-off-by: Linus Torvalds > > > > which doesn't really tell all that much. The historical baggage and a > > long term behavior which is not really trivial to fix I suspect. > > Thinking about this some more, this logic makes some sense afterall. > Especially in the world without memory hotplug which was very likely the > case back then. It is much better to have compact node mask rather than > sparse one. After all node numbers shouldn't really matter as long as > you have a clear mapping to the HW. I am not sure we export that > information (except for the kernel ring buffer) though. > > 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 -- Thanks and Regards Srikar Dronamraju 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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 3BF64C433E1 for ; Fri, 3 Jul 2020 13:02:25 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EB5A9206B7 for ; Fri, 3 Jul 2020 13:02:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EB5A9206B7 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=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 49yw9B3rb8zDr44 for ; Fri, 3 Jul 2020 23:02:22 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=linux.vnet.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=srikar@linux.vnet.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=fail (p=none dis=none) header.from=linux.vnet.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 49yw635XDTzDrGG for ; Fri, 3 Jul 2020 22:59:39 +1000 (AEST) Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 063CUb5E062981; Fri, 3 Jul 2020 08:58:31 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 321cve9ke5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 03 Jul 2020 08:58:30 -0400 Received: from m0098420.ppops.net (m0098420.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 063CWM5N068303; Fri, 3 Jul 2020 08:58:30 -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 321cve9kdg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 03 Jul 2020 08:58:30 -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 063CkiGd024370; Fri, 3 Jul 2020 12:58:28 GMT Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by ppma06ams.nl.ibm.com with ESMTP id 31wwch6tw9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 03 Jul 2020 12:58:28 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 063CwQNW63176796 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 3 Jul 2020 12:58:26 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 73BE052051; Fri, 3 Jul 2020 12:58:26 +0000 (GMT) Received: from linux.vnet.ibm.com (unknown [9.126.150.29]) by d06av21.portsmouth.uk.ibm.com (Postfix) with SMTP id DDCCA5204E; Fri, 3 Jul 2020 12:58:23 +0000 (GMT) Date: Fri, 3 Jul 2020 18:28:23 +0530 From: Srikar Dronamraju To: Michal Hocko Subject: Re: [PATCH v5 3/3] mm/page_alloc: Keep memoryless cpuless node 0 offline Message-ID: <20200703125823.GA26243@linux.vnet.ibm.com> References: <20200701084200.GN2369@dhcp22.suse.cz> <20200701100442.GB17918@linux.vnet.ibm.com> <184102af-ecf2-c834-db46-173ab2e66f51@redhat.com> <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> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20200703105944.GS18446@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=2020-07-03_06:2020-07-02, 2020-07-03 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=999 priorityscore=1501 spamscore=0 suspectscore=0 phishscore=0 clxscore=1011 bulkscore=0 malwarescore=0 adultscore=0 mlxscore=0 cotscore=-2147483648 lowpriorityscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2007030086 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Srikar Dronamraju Cc: Gautham R Shenoy , Andi Kleen , David Hildenbrand , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Satheesh Rajendran , Mel Gorman , "Kirill A. Shutemov" , Andrew Morton , Michal Such?nek , Linus Torvalds , Christopher Lameter , Vlastimil Babka Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" * Michal Hocko [2020-07-03 12:59:44]: > > Honestly, I do not have any idea. I've traced it down to > > Author: Andi Kleen > > Date: Tue Jan 11 15:35:48 2005 -0800 > > > > [PATCH] x86_64: Fix ACPI SRAT NUMA parsing > > > > Fix fallout from the recent nodemask_t changes. The node ids assigned > > in the SRAT parser were off by one. > > > > I added a new first_unset_node() function to nodemask.h to allocate > > IDs sanely. > > > > Signed-off-by: Andi Kleen > > Signed-off-by: Linus Torvalds > > > > which doesn't really tell all that much. The historical baggage and a > > long term behavior which is not really trivial to fix I suspect. > > Thinking about this some more, this logic makes some sense afterall. > Especially in the world without memory hotplug which was very likely the > case back then. It is much better to have compact node mask rather than > sparse one. After all node numbers shouldn't really matter as long as > you have a clear mapping to the HW. I am not sure we export that > information (except for the kernel ring buffer) though. > > 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 -- Thanks and Regards Srikar Dronamraju