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, 6 Jan 2002 08:12:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 6 Jan 2002 08:12:08 -0500 Received: from holomorphy.com ([216.36.33.161]:25801 "EHLO holomorphy") by vger.kernel.org with ESMTP id ; Sun, 6 Jan 2002 08:11:54 -0500 Date: Sun, 6 Jan 2002 05:11:34 -0800 From: William Lee Irwin III To: Anton Blanchard Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] Remove 8 bytes from struct page on 64bit archs Message-ID: <20020106051134.E10391@holomorphy.com> Mail-Followup-To: William Lee Irwin III , Anton Blanchard , linux-kernel@vger.kernel.org In-Reply-To: <20020106123913.GA5407@krispykreme> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Description: brief message Content-Disposition: inline User-Agent: Mutt/1.3.17i In-Reply-To: <20020106123913.GA5407@krispykreme>; from anton@samba.org on Sun, Jan 06, 2002 at 11:39:14PM +1100 Organization: The Domain of Holomorphy Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jan 06, 2002 at 11:39:14PM +1100, Anton Blanchard wrote: > It seems shortening struct page is all the rage at the moment and I > didnt want to be left out. On some 64bit architectures (sparc64 and > ppc64 for example) all memory is allocated in the DMA zone. Therefore > there is no reason to waste 8 bytes per page when every page points to > the same zone! Very true. I devised something to address this that appears to work on multiple architectures already by folding ->zone into ->flags, which could be useful. (Dave Jones recommended I just let arch maintainers for things other than i386 mess with page_address() for other arches.) OTOH, I'm more interested in getting it trimmed down than getting credit. Cheers, Bill P.S.: My i386 version, which makes ->virtual conditional on CONFIG_HIGHMEM as well, is at: ftp://ftp.kernel.org/pub/linux/kernel/people/wli/vm/struct_page/struct_page-2.4.17-rc2