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=-2.3 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 472A1C73C6D for ; Wed, 10 Jul 2019 05:59:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 29B1E20838 for ; Wed, 10 Jul 2019 05:59:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726991AbfGJF7M (ORCPT ); Wed, 10 Jul 2019 01:59:12 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:46746 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725791AbfGJF7M (ORCPT ); Wed, 10 Jul 2019 01:59:12 -0400 Received: from pd9ef1cb8.dip0.t-ipconnect.de ([217.239.28.184] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1hl5cV-0004bB-Pv; Wed, 10 Jul 2019 07:58:23 +0200 Date: Wed, 10 Jul 2019 07:58:21 +0200 (CEST) From: Thomas Gleixner To: Hoan Tran OS cc: Catalin Marinas , Will Deacon , Andrew Morton , Michal Hocko , Vlastimil Babka , Oscar Salvador , Pavel Tatashin , Mike Rapoport , Alexander Duyck , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , "David S . Miller" , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , "open list:MEMORY MANAGEMENT" , "linux-arm-kernel@lists.infradead.org" , "linux-s390@vger.kernel.org" , "sparclinux@vger.kernel.org" , "x86@kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" , Open Source Submission Subject: Re: [PATCH 3/5] x86: Kconfig: Remove CONFIG_NODES_SPAN_OTHER_NODES In-Reply-To: <1c5bc3a8-0c6f-dce3-95a2-8aec765408a2@os.amperecomputing.com> Message-ID: References: <1561501810-25163-1-git-send-email-Hoan@os.amperecomputing.com> <1561501810-25163-4-git-send-email-Hoan@os.amperecomputing.com> <1c5bc3a8-0c6f-dce3-95a2-8aec765408a2@os.amperecomputing.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hoan, On Wed, 10 Jul 2019, Hoan Tran OS wrote: > On 6/25/19 3:45 PM, Thomas Gleixner wrote: > > On Tue, 25 Jun 2019, Hoan Tran OS wrote: > >> @@ -1567,15 +1567,6 @@ config X86_64_ACPI_NUMA > >> ---help--- > >> Enable ACPI SRAT based node topology detection. > >> > >> -# Some NUMA nodes have memory ranges that span > >> -# other nodes. Even though a pfn is valid and > >> -# between a node's start and end pfns, it may not > >> -# reside on that node. See memmap_init_zone() > >> -# for details. > >> -config NODES_SPAN_OTHER_NODES > >> - def_bool y > >> - depends on X86_64_ACPI_NUMA > > > > the changelog does not mention that this lifts the dependency on > > X86_64_ACPI_NUMA and therefore enables that functionality for anything > > which has NUMA enabled including 32bit. > > > > I think this config is used for a NUMA layout which NUMA nodes addresses > are spanned to other nodes. I think 32bit NUMA also have the same issue > with that layout. Please correct me if I'm wrong. I'm not saying you're wrong, but it's your duty to provide the analysis why this is correct for everything which has NUMA enabled. > > The core mm change gives no helpful information either. You just copied the > > above comment text from some random Kconfig. > > Yes, as it's a correct comment and is used at multiple places. Well it maybe correct in terms of explaining what this is about, it still does not explain why this is needed by default on everything which has NUMA enabled. Thanks, tglx