Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 19 Jun 2002 22:08:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 19 Jun 2002 22:08:44 -0400 Received: from holomorphy.com ([66.224.33.161]:35772 "EHLO holomorphy") by vger.kernel.org with ESMTP id ; Wed, 19 Jun 2002 22:08:38 -0400 Date: Wed, 19 Jun 2002 19:08:09 -0700 From: William Lee Irwin III To: marc.miller@amd.com Cc: devnull@adc.idt.com, linux-kernel@vger.kernel.org Subject: Re: >3G Memory support Message-ID: <20020620020809.GS22961@holomorphy.com> Mail-Followup-To: William Lee Irwin III , marc.miller@amd.com, devnull@adc.idt.com, linux-kernel@vger.kernel.org References: <858788618A93D111B45900805F85267A062BB49D@caexmta3.amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Description: brief message Content-Disposition: inline In-Reply-To: <858788618A93D111B45900805F85267A062BB49D@caexmta3.amd.com> User-Agent: Mutt/1.3.25i Organization: The Domain of Holomorphy Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1241 Lines: 26 On Wed, Jun 19, 2002 at 07:01:08PM -0700, marc.miller@amd.com wrote: > Support of 4G of RAM is a configuration option when you compile the > kernel. Is that setting turned on? > I think it's in "General Options" when you do a "make menuconfig" > (I don't have a machine up at the moment that I can check). There > are three options: Less than 1G, 1G to less than 4G, and 4G or more. > That last option is the one you would want. > If that's already enabled, hopefully one of the memory guys can pitch in... This is actually yet another "32-bit virtualspace sucks" issue. You can't get at all your RAM from userspace because the virtualspace set aside for the kernel prevents you from using it to map physical memory. 64-bit virtualspace is too vast to be easily exhausted this way. The original form of highmem was "BIGMEM" which used (almost) disjoint user and kernel virtual address spaces, but this is not terribly efficient with respect to lazy TLB entry invalidation. Cheers, Bill - 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/