From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 5 May 2002 20:55:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 5 May 2002 20:55:16 -0400 Received: from caramon.arm.linux.org.uk ([212.18.232.186]:2823 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id ; Sun, 5 May 2002 20:55:16 -0400 Date: Mon, 6 May 2002 01:55:05 +0100 From: Russell King To: Daniel Phillips Cc: Andrea Arcangeli , "Martin J. Bligh" , linux-kernel@vger.kernel.org Subject: Re: Bug: Discontigmem virt_to_page() [Alpha,ARM,Mips64?] Message-ID: <20020506015505.B14956@flint.arm.linux.org.uk> In-Reply-To: <20020502180632.I11414@dualathlon.random> <20020503071554.P11414@dualathlon.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 06, 2002 at 01:54:52AM +0200, Daniel Phillips wrote: > I must be guilty of not explaining clearly. Suppose you have the following > physical memory map: > > 0: 128 MB > 8000,0000: 128 MB > 1,0000,0000: 128 MB > 1,8000,0000: 128 MB > 2,0000,0000: 128 MB > 2,8000,0000: 128 MB > 3,0000,0000: 128 MB > 3,8000,0000: 128 MB > > The total is 1 GB of installed ram. Yet the kernel's 1G virtual space, > can only handle 128 MB of it. I see no problem with the above with the existing discontigmem stuff. discontigmem does *not* require a linear relationship between kernel virtual and physical memory. I've been running kernels for a while on such systems. Which was the reason for my comment at the start of this thread: | On ARM, however, we have cherry to add here. __va() may alias certain | physical memory addresses to the same virtual memory address, which | makes: -- Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux http://www.arm.linux.org.uk/personal/aboutme.html