From patchwork Wed Mar 9 17:22:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Rapoport X-Patchwork-Id: 12775347 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 C9B58C433F5 for ; Wed, 9 Mar 2022 17:23:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 572D78D0003; Wed, 9 Mar 2022 12:23:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 522D68D0001; Wed, 9 Mar 2022 12:23:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 411D98D0003; Wed, 9 Mar 2022 12:23:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0075.hostedemail.com [216.40.44.75]) by kanga.kvack.org (Postfix) with ESMTP id 3414C8D0001 for ; Wed, 9 Mar 2022 12:23:09 -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 E600F8249980 for ; Wed, 9 Mar 2022 17:23:08 +0000 (UTC) X-FDA: 79225518456.18.1A24BBC Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf28.hostedemail.com (Postfix) with ESMTP id 5CB20C000D for ; Wed, 9 Mar 2022 17:23:08 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 747EA60C1C; Wed, 9 Mar 2022 17:23:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A497C340E8; Wed, 9 Mar 2022 17:23:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646846586; bh=mSXOxDm0YQ/4bRgksAVQhm0M51442VyGvpFWc/rjdAg=; h=From:To:Cc:Subject:Date:From; b=hwmGntSJzO+BOdWggrE8RO+wwrUWI5gbLemWvf6pRnlLQT3jdEGQn6/I2fNO0Kahh 4PwGFv0QZsr/4eNoxgttSNHt0mCaU1IaxO8rRyXD0E7UeZ+WgRTErF193RDDP4c10h Efh3Akk9SCJYaK020CxPZrQlmQCGLsI2kGwi6ThM0rJoGgrJjPOKT9Ym/SMeediYrx AmCoB6t3UphglNfOrXN96U+9h1bIakCmmGCuaDafwuHFGtZTYtagakME47Gm9HHerH dN+CBm5CnUaD1LpKhSNb8v5MaiJVTd6BMFjyBbP9o6lcqs3EaaBxq+i7Id9IGVbzxg vry6HNW6enpRg== From: Mike Rapoport To: Jonathan Corbet Cc: Andrew Morton , "Maciej W. Rozycki" , Mike Rapport , Mike Rapoport , Randy Dunlap , Sergey Shtylyov , Tiezhu Yang , Thomas Bogendoerfer , linux-doc@vger.kernel.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] docs/kernel-parameters: update description of mem= Date: Wed, 9 Mar 2022 19:22:58 +0200 Message-Id: <20220309172258.1183796-1-rppt@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Rspamd-Queue-Id: 5CB20C000D X-Stat-Signature: jyz18fg8g5d3ouw7rq4chww3hkgcw6zy X-Rspam-User: Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=hwmGntSJ; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf28.hostedemail.com: domain of rppt@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=rppt@kernel.org X-Rspamd-Server: rspam03 X-HE-Tag: 1646846588-878169 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: From: Mike Rapoport The existing description of mem= does not cover all the cases and differences between how architectures treat it. Extend the description to match the code. Signed-off-by: Mike Rapoport --- v1: https://lore.kernel.org/all/20220309122446.1118738-1-rppt@kernel.org * drop clumsy and redundant paragraph about Hexagon .../admin-guide/kernel-parameters.txt | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index f5a27f067db9..40cd4136331b 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2834,6 +2834,13 @@ 2 when the kernel is not able to see the whole system memory; 3 memory that lies after 'mem=' boundary is excluded from the hypervisor, then assigned to KVM guests. + 4 to limit the memory available for kdump kernel. + + [ARC,MICROBLAZE] - the limit applies only to low memory, + high memory is not affected. + + [ARM64] - only limits memory covered by the linear + mapping. The NOMAP regions are not affected. [X86] Work as limiting max address. Use together with memmap= to avoid physical address space collisions. @@ -2844,6 +2851,17 @@ in above case 3, memory may need be hot added after boot if system memory of hypervisor is not sufficient. + mem=nn[KMG]@ss[KMG] + [ARM,MIPS] - override the memory layout reported by + firmware. + Define a memory region of size nn[KMG] starting at + ss[KMG]. + Multiple different regions can be specified with + multiple mem= parameters on the command line. + + mem=nn[KMG] [HEXAGON] Set the memory size. + Must be specified, otherwise memory size will be 0. + mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel memory.