Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 7 Dec 2001 20:29:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 7 Dec 2001 20:29:09 -0500 Received: from neon-gw-l3.transmeta.com ([63.209.4.196]:23301 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id ; Fri, 7 Dec 2001 20:28:58 -0500 Message-ID: <3C116CC6.2030808@zytor.com> Date: Fri, 07 Dec 2001 17:28:38 -0800 From: "H. Peter Anvin" Organization: Zytor Communications User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.4) Gecko/20010913 X-Accept-Language: en, sv MIME-Version: 1.0 To: mjustice@austin.rr.com CC: linux-kernel@vger.kernel.org Subject: Re: highmem question In-Reply-To: <9url8t$nmo$1@cesium.transmeta.com> <01120719300102.00764@bozo> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Marvin Justice wrote: > > While it certainly makes sense to expect a performance hit for mem above 4GB > on 32 bit systems I don't see why there should be any a priori reason to > either move to 64 bit or take a performance hit for if you need, say, 2GB of > RAM. The problem is that 2.4 Linux considers HIGHMEM to be anything above > 896MB. > The problem is that in the x86 architecture you don't have any reasonable way of addressing the physical address space, so you need to map it into the virtual address space. You end up with a shortage of virtual address space. > >>From what I've read it looks like there will be changes in 2.5 to fix all > this. > There is no way of fixing it. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/