From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932078AbWGCX3T (ORCPT ); Mon, 3 Jul 2006 19:29:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932085AbWGCX3T (ORCPT ); Mon, 3 Jul 2006 19:29:19 -0400 Received: from omx1-ext.sgi.com ([192.48.179.11]:13991 "EHLO omx1.americas.sgi.com") by vger.kernel.org with ESMTP id S932078AbWGCX3T (ORCPT ); Mon, 3 Jul 2006 19:29:19 -0400 Date: Mon, 3 Jul 2006 16:26:57 -0700 (PDT) From: Christoph Lameter To: Christoph Hellwig cc: linux-kernel@vger.kernel.org, akpm@osdl.org, Hugh Dickins , Con Kolivas , Marcelo Tosatti , Nick Piggin , Andi Kleen Subject: Re: [RFC 0/8] Reduce MAX_NR_ZONES and remove useless zones. In-Reply-To: <20060703221712.GB14273@infradead.org> Message-ID: References: <20060703215534.7566.8168.sendpatchset@schroedinger.engr.sgi.com> <20060703221712.GB14273@infradead.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 3 Jul 2006, Christoph Hellwig wrote: > On Mon, Jul 03, 2006 at 02:55:34PM -0700, Christoph Lameter wrote: > > I keep seeing zones on various platforms that are never used and wonder > > why we compile support for them into the kernel. > > > > IA64 on SGI for example only uses ZONE_DMA other IA64 platforms can > > also use ZONE_NORMAL. > > Which btw is utterly wrong. It should have a 4GB ZONE_DMA32 and everything > else in ZONE_NORMAL. So we want to change the definition of ZONE_DMA to refer to the first 16MB only? ZONE_DMA32 is always a 4GB border? (Andy disagrees about DMA32 see his message!). It seems to me that DMA can be run on ZONE_NORMAL. ZONE_DMAxx is used for situations in which DMA cannot be done to all of memory. ZONE_DMA allows an architecture to define a single exception zone that ends at MAX_DMA_ADDRESS (which is arch specific).