From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 20 May 2004 21:27:18 +0100 (BST) Received: from [IPv6:::ffff:68.118.232.104] ([IPv6:::ffff:68.118.232.104]:12735 "EHLO gallardo") by linux-mips.org with ESMTP id ; Thu, 20 May 2004 21:27:17 +0100 Received: by gallardo (Postfix, from userid 1000) id 0C6C6AC2084; Thu, 20 May 2004 16:27:04 -0400 (EDT) Date: Thu, 20 May 2004 16:27:04 -0400 From: Daniel Walton To: linux-mips@linux-mips.org Subject: Re: Using more than 256 MB of memory on SB1250 in 32-bit mode Message-ID: <20040520202703.GA24477@ddtsm.com> Reply-To: Daniel Walton References: <3F4FCCD5.1000604@tadpole.com> <20030831133434.GA23189@linux-mips.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030831133434.GA23189@linux-mips.org> User-Agent: Mutt/1.5.5.1+cvs20040105i Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 5089 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: dwalton+mips@ddtsm.com Precedence: bulk X-list: linux-mips On Sun, Aug 31, 2003 at 03:34:34PM +0200, Ralf Baechle wrote: > The explanation you gave isn't exactly right. A 2GB/2GB split would normally > support 2GB of low memory. We don't on MIPS due to the very inconvenient and > unchangable mappings of KSEG0/KSEG1 - something that may have been sweet > in '85 when the address map was designed but not today when 32-bit address > spaces are beginning to be fairly tight. > > Highmem works ok in 2.4 as long as you have a reasonably low ratio of > highmem to lowmem. For typical loads that means going beyond 4:1 isn't > sensible but the actual number may vary much based on exact system > configuration or workload. > > Ralf > So what is a practical limit to total memory. Daniel