From patchwork Thu Mar 10 08:27:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Rapoport X-Patchwork-Id: 12776028 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 7F717C433F5 for ; Thu, 10 Mar 2022 08:27:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 17C278D0002; Thu, 10 Mar 2022 03:27:48 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 12B318D0001; Thu, 10 Mar 2022 03:27:48 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 040E48D0002; Thu, 10 Mar 2022 03:27:47 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.a.hostedemail.com [64.99.140.24]) by kanga.kvack.org (Postfix) with ESMTP id E50FC8D0001 for ; Thu, 10 Mar 2022 03:27:47 -0500 (EST) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay11.hostedemail.com (Postfix) with ESMTP id A302080B24 for ; Thu, 10 Mar 2022 08:27:47 +0000 (UTC) X-FDA: 79227798174.04.45EA603 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf15.hostedemail.com (Postfix) with ESMTP id 0063AA0010 for ; Thu, 10 Mar 2022 08:27:46 +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 ams.source.kernel.org (Postfix) with ESMTPS id 1941FB824C7; Thu, 10 Mar 2022 08:27:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A27CC340E8; Thu, 10 Mar 2022 08:27:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646900863; bh=lH6TNST8z+31kpvCNG8FuLutvp8PxFIvRRmTnLYxqCw=; h=From:To:Cc:Subject:Date:From; b=DQegw6R5caHc88KySqVtU1vH86//yELhBTtsmfAnD12HZsUdI7G2QvqpH0QQeqMwX QQ5ohxya3KLIHlBinvH57fX5ED4ji1IpiV60pX9v+hJMOn4igo3J6d5stPpbvlWvw0 IS0wfHyGXTsdnowDoiEdIqGYWMz+siZ6n6d5GfAoiiLPkUYEr8K9rxXCzfZjqefnyA w426wDkwnYMcazj6cIEvu1Fgwmlbo3jsUbvIbSrwsW/MvT17zWpXUqbaK3nEX+9gBB gBWLU7h4Zepz+1JHkyk70RbwzdMWkPeByENTonVstUGhZyFaBS9x+dnu4gPx9DStV3 Nia9AZme1QDAQ== 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 v3] docs/kernel-parameters: update description of mem= Date: Thu, 10 Mar 2022 10:27:36 +0200 Message-Id: <20220310082736.1346366-1-rppt@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 0063AA0010 X-Stat-Signature: du1oxm6jdaizyuq8yxie5b6ja571d3yo Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=DQegw6R5; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf15.hostedemail.com: domain of rppt@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=rppt@kernel.org X-HE-Tag: 1646900866-906877 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 --- v2: https://lore.kernel.org/all/20220309172258.1183796-1-rppt@kernel.org * move Hexagon description to make it better visible 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..5b84cca62990 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2827,6 +2827,9 @@ For details see: Documentation/admin-guide/hw-vuln/mds.rst + mem=nn[KMG] [HEXAGON] Set the memory size. + Must be specified, otherwise memory size will be 0. + mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory Amount of memory to be used in cases as follows: @@ -2834,6 +2837,13 @@ 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 +2854,14 @@ 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=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel memory.