From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (from majordomo@localhost) by oss.sgi.com (8.11.2/8.11.3) id g16DHri20298 for linux-mips-outgoing; Wed, 6 Feb 2002 05:17:53 -0800 Received: from holomorphy (mail@holomorphy.com [216.36.33.161]) by oss.sgi.com (8.11.2/8.11.3) with SMTP id g16DHmA20295; Wed, 6 Feb 2002 05:17:48 -0800 Received: from wli by holomorphy with local (Exim 3.33 #1 (Debian)) id 16YRx7-0002tw-00; Wed, 06 Feb 2002 05:17:33 -0800 Date: Wed, 6 Feb 2002 05:17:33 -0800 From: William Lee Irwin III To: Ralf Baechle Cc: "Steven J. Hill" , linux-mips@oss.sgi.com Subject: Re: What is the maximum physical RAM for a 32bit MIPS core? Message-ID: <20020206131733.GF744@holomorphy.com> References: <3C600D4C.43CBA784@cotw.com> <20020206033346.A7298@dea.linux-mips.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Description: brief message Content-Disposition: inline In-Reply-To: <20020206033346.A7298@dea.linux-mips.net> User-Agent: Mutt/1.3.25i Organization: The Domain of Holomorphy Sender: owner-linux-mips@oss.sgi.com Precedence: bulk On Tue, Feb 05, 2002 at 10:50:20AM -0600, Steven J. Hill wrote: >> I am just trying to fill in some more MIPS knowledge here. With a 32-bit >> MIPS processor, we are forever limited to a userspace of 2GB in size thanks >> to the kuser region. kseg0/1 map the same 512MB of physical memory. kseg2 >> is 1GB in size and hence it could address another 1GB of RAM. So, is the On Wed, Feb 06, 2002 at 03:33:46AM +0100, Ralf Baechle wrote: > 2gb virtual memory per process. In theory physical memory is limited by > the size of the address bus with highmem; the practical limit for highmem > should be in the range of 16-32gb RAM. I'm aware that some of those issues have to do with boot-time allocations proportional to memory size filling the direct-mapped portion of the kernel virtual address space. Do you have in mind others? I'm just generally curious. Thanks, Bill