From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f174.google.com (mail-ie0-f174.google.com [209.85.223.174]) by kanga.kvack.org (Postfix) with ESMTP id C15636B0035 for ; Thu, 30 Jan 2014 14:25:16 -0500 (EST) Received: by mail-ie0-f174.google.com with SMTP id tp5so3578293ieb.5 for ; Thu, 30 Jan 2014 11:25:16 -0800 (PST) Received: from merlin.infradead.org (merlin.infradead.org. [2001:4978:20e::2]) by mx.google.com with ESMTPS id yr5si10994454igb.44.2014.01.30.11.25.11 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 30 Jan 2014 11:25:12 -0800 (PST) Message-ID: <52EAA714.3080809@infradead.org> Date: Thu, 30 Jan 2014 11:25:08 -0800 From: Randy Dunlap MIME-Version: 1.0 Subject: Re: [BUG] Description for memmap in kernel-parameters.txt is wrong References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andiry Xu , linux-kernel@vger.kernel.org Cc: Andiry Xu , Linux MM [adding linux-mm mailing list] On 01/30/2014 08:52 AM, Andiry Xu wrote: > Hi, > > In kernel-parameters.txt, there is following description: > > memmap=nn[KMG]$ss[KMG] > [KNL,ACPI] Mark specific memory as reserved. > Region of memory to be used, from ss to ss+nn. Should be: Region of memory to be reserved, from ss to ss+nn. but that doesn't help with the problem that you describe, does it? > Unfortunately this is incorrect. The meaning of nn and ss is reversed. > For example: > > Command Expected Result > memmap 2G$6G 6G - 8G reserved 2G - 8G reserved > memmap 6G$2G 2G - 8G reserved 6G - 8G reserved Are you testing on x86? The code in arch/x86/kernel/e820.c always parses mem_size followed by start address. I don't (yet) see where it goes wrong... > Test kernel version 3.13, but I believe the issue has been there long ago. > > I'm not sure whether the description or implementation should be > fixed, but apparently they do not match. I prefer to change the documentation and leave the implementation as is. -- ~Randy -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org