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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id CAE94C433EF for ; Tue, 15 Feb 2022 04:47:15 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0584C6B0078; Mon, 14 Feb 2022 23:47:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0077C6B007B; Mon, 14 Feb 2022 23:47:14 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E38226B007D; Mon, 14 Feb 2022 23:47:14 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0002.hostedemail.com [216.40.44.2]) by kanga.kvack.org (Postfix) with ESMTP id D67A16B007B for ; Mon, 14 Feb 2022 23:47:14 -0500 (EST) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 880F48249980 for ; Tue, 15 Feb 2022 04:47:14 +0000 (UTC) X-FDA: 79143779988.18.EFC8B1F Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf13.hostedemail.com (Postfix) with ESMTP id CF07520007 for ; Tue, 15 Feb 2022 04:47:13 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 07FD01063; Mon, 14 Feb 2022 20:47:13 -0800 (PST) Received: from [10.163.48.145] (unknown [10.163.48.145]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BFE7E3F718; Mon, 14 Feb 2022 20:47:10 -0800 (PST) Subject: Re: [PATCH] mm/pages_alloc.c: Don't create ZONE_MOVABLE beyond the end of a node To: Alistair Popple , akpm@linux-foundation.org Cc: jhubbard@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ziy@nvidia.com References: <20220215025831.2113067-1-apopple@nvidia.com> From: Anshuman Khandual Message-ID: <7b752e06-f345-cbb2-d05c-57e5fc5d8e5a@arm.com> Date: Tue, 15 Feb 2022 10:17:09 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20220215025831.2113067-1-apopple@nvidia.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: CF07520007 X-Rspam-User: Authentication-Results: imf13.hostedemail.com; dkim=none; spf=pass (imf13.hostedemail.com: domain of anshuman.khandual@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com; dmarc=pass (policy=none) header.from=arm.com X-Stat-Signature: ogc5emsdqeoydwuwwc37ubzxuznb788e X-Rspamd-Server: rspam03 X-HE-Tag: 1644900433-821890 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: Hi Alistair, On 2/15/22 8:28 AM, Alistair Popple wrote: > ZONE_MOVABLE uses the remaining memory in each node. It's starting pfn > is also aligned to MAX_ORDER_NR_PAGES. It is possible for the remaining > memory in a node to be less than MAX_ORDER_NR_PAGES, meaning there is > not enough room for ZONE_MOVABLE on that node. How plausible is this scenario on normal systems ? Should not the node always contain MAX_ORDER_NR_PAGES aligned pages ? Also all zones which get created from that node should also be MAX_ORDER_NR_PAGES aligned ? I am just curious how a node could end up being like this. - Anshuman