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 5DB82C433EF for ; Fri, 4 Mar 2022 15:14:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B34118D0002; Fri, 4 Mar 2022 10:14:08 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AE4078D0001; Fri, 4 Mar 2022 10:14:08 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9D24E8D0002; Fri, 4 Mar 2022 10:14:08 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0195.hostedemail.com [216.40.44.195]) by kanga.kvack.org (Postfix) with ESMTP id 8EECC8D0001 for ; Fri, 4 Mar 2022 10:14:08 -0500 (EST) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 4B2B692EDE for ; Fri, 4 Mar 2022 15:14:08 +0000 (UTC) X-FDA: 79207049376.17.1FBBE40 Received: from elvis.franken.de (elvis.franken.de [193.175.24.41]) by imf10.hostedemail.com (Postfix) with ESMTP id 91092C002E for ; Fri, 4 Mar 2022 15:14:07 +0000 (UTC) Received: from uucp (helo=alpha) by elvis.franken.de with local-bsmtp (Exim 3.36 #1) id 1nQ9d5-0008Id-00; Fri, 04 Mar 2022 16:14:03 +0100 Received: by alpha.franken.de (Postfix, from userid 1000) id 373FEC0F3F; Fri, 4 Mar 2022 16:10:52 +0100 (CET) Date: Fri, 4 Mar 2022 16:10:52 +0100 From: Thomas Bogendoerfer To: Tiezhu Yang Cc: Mike Rapoport , Andrew Morton , Xuefeng Li , linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 1/4] MIPS: Refactor early_parse_mem() to fix mem= parameter Message-ID: <20220304151052.GA27642@alpha.franken.de> References: <1646108941-27919-1-git-send-email-yangtiezhu@loongson.cn> <1646108941-27919-2-git-send-email-yangtiezhu@loongson.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1646108941-27919-2-git-send-email-yangtiezhu@loongson.cn> User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 91092C002E X-Stat-Signature: ui71x8m11y965kcfj9ene4fz7ewubzgq Authentication-Results: imf10.hostedemail.com; dkim=none; dmarc=none; spf=none (imf10.hostedemail.com: domain of tsbogend@alpha.franken.de has no SPF policy when checking 193.175.24.41) smtp.mailfrom=tsbogend@alpha.franken.de X-HE-Tag: 1646406847-82749 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: On Tue, Mar 01, 2022 at 12:28:58PM +0800, Tiezhu Yang wrote: > According to Documentation/admin-guide/kernel-parameters.txt, > the kernel command-line parameter mem= means "Force usage of > a specific amount of memory", but when add "mem=3G" to the > command-line, kernel boot hangs in sparse_init(). > > This commit is similar with the implementation of the other > archs such as arm64, powerpc and riscv, refactor the function > early_parse_mem() and then use memblock_enforce_memory_limit() > to limit the memory size. > > With this patch, when add "mem=3G" to the command-line, the > kernel boots successfully, we can see the following messages: unfortunately this patch would break platforms without memory detection, which simply use mem=32M for memory configuration. Not sure how many rely on this mechanism. If we can make sure nobody uses it, I'm fine with your patch. Thomas. -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea. [ RFC1925, 2.3 ]