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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 839B1C433F5 for ; Wed, 9 Mar 2022 12:24:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232752AbiCIMZz (ORCPT ); Wed, 9 Mar 2022 07:25:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54592 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232675AbiCIMZy (ORCPT ); Wed, 9 Mar 2022 07:25:54 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B834413CA1A; Wed, 9 Mar 2022 04:24:55 -0800 (PST) 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 547EF61973; Wed, 9 Mar 2022 12:24:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF364C340E8; Wed, 9 Mar 2022 12:24:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646828694; bh=4U9KSoGP/RtOc59UTrmURxuIAqJs03Ww/sR14qn3McE=; h=From:To:Cc:Subject:Date:From; b=lMwopPMwwqoJU+2rf9HLq3gT33A036hqF5JzPJ2acELq9oQmVWQkPkntO42iHi+Q9 QEOQtWvhORZEvz21vMU+o3MTM9Lh//WiZPNq6Tkx/UejcYF8P+v2u5ZWEbfjOFCHRo 68wEYSCXi7GW9zk/Im3sc2wruaqGP1U3Ru1do6H9OFcAnq2UXNQScCutFxN+SbhUES /XQt1tMtJZbWEWKRKITi/I5s+50Vv/dZVagW0PQRcy/YMYKjLN6dTSIgNgG2oOrFgB ccXh2Wm32YJ1xg8FNd+hQyB2zxk4+/nn3pfVGi0rw/B9Ocb96E/HmnnzFPlj8l2dwK GCkMmGtZKHQLg== From: Mike Rapoport To: Jonathan Corbet Cc: Andrew Morton , "Maciej W. Rozycki" , Mike Rapport , Mike Rapoport , 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] docs/kernel-parameters: update description of mem= Date: Wed, 9 Mar 2022 14:24:46 +0200 Message-Id: <20220309122446.1118738-1-rppt@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- This is in a way a followup for the discussion of mem= usage on MIPS: https://lore.kernel.org/all/1646461289-31992-1-git-send-email-yangtiezhu@loongson.cn .../admin-guide/kernel-parameters.txt | 20 +++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index f5a27f067db9..f3597841a031 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2834,6 +2834,15 @@ 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. + + [HEXAGON] - must be use to set the memory size, there is [X86] Work as limiting max address. Use together with memmap= to avoid physical address space collisions. @@ -2844,6 +2853,17 @@ 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. -- 2.34.1