From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id CA27CDDE08 for ; Sat, 27 Oct 2007 01:03:25 +1000 (EST) In-Reply-To: <4dd2a2ce0710252051pe83a943q48f52d148f5a9603@mail.gmail.com> References: <4dd2a2ce0710252051pe83a943q48f52d148f5a9603@mail.gmail.com> Mime-Version: 1.0 (Apple Message framework v752.2) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <524E69ED-899B-452F-B593-44499C5181A3@kernel.crashing.org> From: Kumar Gala Subject: Re: reg adjust_total_lowmem Date: Fri, 26 Oct 2007 10:04:19 -0500 To: Surya Ravikiran Cc: linuxppc-dev list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Oct 25, 2007, at 10:51 PM, Surya Ravikiran wrote: > Hi, > > I am trying to bootup a Linux kernel, on a FS eval board with 256M. > I pass the kernel argument mem=252M, and see that the kernel boots up > fine, but with much less memory, ~192M (the closes 64M multiple), and > I browsed through the code to see that the adjust_total_lowmem > function does not add up the residual memory to the total memory. > I am trying to understand why I cannot do this reserving of higher end > of the RAM during boot up, > I would appreciate your comments. The reason you have 192M is that lowmem is the total amount of memory that can be covered by up to three CAM entries. In the case of setting mem=252M that max that three CAM entries can cover is 192M (64 +64+64). You should be able to access the other 60M via HIGHMEM. - k