From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 15 Dec 2004 14:15:32 +0000 (GMT) Received: from pD9562F66.dip.t-dialin.net ([IPv6:::ffff:217.86.47.102]:43539 "EHLO mail.linux-mips.net") by linux-mips.org with ESMTP id ; Wed, 15 Dec 2004 14:15:28 +0000 Received: from fluff.linux-mips.net (localhost.localdomain [127.0.0.1]) by mail.linux-mips.net (8.13.1/8.13.1) with ESMTP id iBFEFC5u029252; Wed, 15 Dec 2004 15:15:12 +0100 Received: (from ralf@localhost) by fluff.linux-mips.net (8.13.1/8.13.1/Submit) id iBFEF8Wj029250; Wed, 15 Dec 2004 15:15:08 +0100 Date: Wed, 15 Dec 2004 15:15:08 +0100 From: Ralf Baechle To: Hdei Nunoe Cc: linux-mips@linux-mips.org Subject: Re: HIGHMEM Message-ID: <20041215141508.GA29222@linux-mips.org> References: <001101c4dbf9$1da02270$3ca06096@NUNOE> <20041207095837.GA13264@linux-mips.org> <001701c4e195$24d48260$3ca06096@NUNOE> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <001701c4e195$24d48260$3ca06096@NUNOE> User-Agent: Mutt/1.4.1i 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: 6669 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: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Tue, Dec 14, 2004 at 01:26:55PM +0900, Hdei Nunoe wrote: > >In 2.4 the support for CONFIG_DISCONTIG and CONFIG_NUMA are a bit tangled > >with each other because IP27 is the only platform to uses these features > >and it needs both. > > Is it named "sgi-ip27"? Yes, obviously :-) > >Other than that you can also just setup your system > >as 0x0 - 0x10000000 being RAM, 0x10000000 - 0x20000000 being reserved > >memory and 0x20000000 - 0x30000000 being highmem. Which works but is a > >bit wasteful. > > The gap in physical memory is 0x10000000 - 0x20000000, but it is > 0x90000000 - > 0xC0000000 in virtual memory because there is K1 segment. So the macros > such > as __pa() or __va() does not work, I think. Started to wonder it might not > be easy > as just changing the PAGE_OFFSET value. Do you see? PAGE_OFFSET is the difference of a ZONE_NORMAL's virtual address and it's physical address. Once there is no more 1:1 mapping between physical and virtual addresses such as in your suggestion PAGE_OFFSET can no longer be used, that is you need to rewrite all users of this function. Ralf