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 33258C433FE for ; Wed, 9 Mar 2022 17:06:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236620AbiCIRH1 (ORCPT ); Wed, 9 Mar 2022 12:07:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53834 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237029AbiCIRGX (ORCPT ); Wed, 9 Mar 2022 12:06:23 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B8B541B8C93; Wed, 9 Mar 2022 08:56:45 -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 ams.source.kernel.org (Postfix) with ESMTPS id 5E4B7B82221; Wed, 9 Mar 2022 16:56:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E769C340EC; Wed, 9 Mar 2022 16:56:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646845003; bh=kDMnZH3ho28GeAh47qD13Y8CWbmenm3wAL3cZzVX4RY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WZ/fu/uYkB4AJIYeqd2YGCJHbzXsMT7wtZryD15B5YtuYJZeMWLRRgwpit7N06+vW UFi07RAEJ3kC3zLDtLzN51JqEn1mKwerx6wT4FhpgKMpWB8b/6guPjwWdZ0eZh4BqA T1SgIlWeTDml1xiN59Jd8Q66goqaKW4tIa7iYP47RkGtbKaLDj23KE6gXjav4z0ONd V8+1Hhmz1XXp+lkWrgbw/NGdZeC9kY5esWordEN8f5BNH285j6nkBC3KFnrjB5f1we mI6dlmfz3YQXgDEIUBn4B0kxqBWN1knNHs/VhY5NpweCcWb+quwpefXveaeFIUWw4y k7OawS80Qrozw== Date: Wed, 9 Mar 2022 18:56:32 +0200 From: Mike Rapoport To: Randy Dunlap Cc: Jonathan Corbet , Andrew Morton , "Maciej W. Rozycki" , 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: Re: [PATCH] docs/kernel-parameters: update description of mem= Message-ID: References: <20220309122446.1118738-1-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 09, 2022 at 08:05:05AM -0800, Randy Dunlap wrote: > Hi Mike, > > On 3/9/22 04:24, Mike Rapoport wrote: > > 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 > > Above line seems to be missing something? Yes :) > Otherwise looks good AFAIK. > > > > > [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. > > > > -- > ~Randy -- Sincerely yours, Mike.