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 82C60C433DF for ; Mon, 29 Jun 2020 14:58:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4CC9723E24 for ; Mon, 29 Jun 2020 14:58:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4CC9723E24 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E137F8D0002; Mon, 29 Jun 2020 10:58:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D9BE86B005A; Mon, 29 Jun 2020 10:58:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C62F68D0002; Mon, 29 Jun 2020 10:58:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0041.hostedemail.com [216.40.44.41]) by kanga.kvack.org (Postfix) with ESMTP id AA5536B0055 for ; Mon, 29 Jun 2020 10:58:41 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 59471181AC9BF for ; Mon, 29 Jun 2020 14:58:41 +0000 (UTC) X-FDA: 76982556042.25.badge42_2e1297826e70 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 1D8D81804E3A1 for ; Mon, 29 Jun 2020 14:58:41 +0000 (UTC) X-HE-Tag: badge42_2e1297826e70 X-Filterd-Recvd-Size: 2203 Received: from gentwo.org (gentwo.org [3.19.106.255]) by imf07.hostedemail.com (Postfix) with ESMTP for ; Mon, 29 Jun 2020 14:58:40 +0000 (UTC) Received: by gentwo.org (Postfix, from userid 1002) id 2B0E33FF4E; Mon, 29 Jun 2020 14:58:40 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id 291103EA72; Mon, 29 Jun 2020 14:58:40 +0000 (UTC) Date: Mon, 29 Jun 2020 14:58:40 +0000 (UTC) From: Christopher Lameter X-X-Sender: cl@www.lameter.com To: Srikar Dronamraju 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 In-Reply-To: <20200624092846.9194-4-srikar@linux.vnet.ibm.com> Message-ID: References: <20200624092846.9194-1-srikar@linux.vnet.ibm.com> <20200624092846.9194-4-srikar@linux.vnet.ibm.com> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspamd-Queue-Id: 1D8D81804E3A1 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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? 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?