Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934321AbXHMXBW (ORCPT ); Mon, 13 Aug 2007 19:01:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758672AbXHMXBL (ORCPT ); Mon, 13 Aug 2007 19:01:11 -0400 Received: from ns2.suse.de ([195.135.220.15]:46415 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750878AbXHMXBJ (ORCPT ); Mon, 13 Aug 2007 19:01:09 -0400 Date: Tue, 14 Aug 2007 01:55:18 +0200 From: Andi Kleen To: Christoph Lameter Cc: Andi Kleen , Mel Gorman , Lee.Schermerhorn@hp.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 3/4] Embed zone_id information within the zonelist->zones pointer Message-ID: <20070813235518.GK3406@bingen.suse.de> References: <200708110304.55433.ak@suse.de> <20070813225020.GE3406@bingen.suse.de> <20070813225841.GG3406@bingen.suse.de> <20070813230801.GH3406@bingen.suse.de> <20070813234217.GI3406@bingen.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2055 Lines: 53 On Mon, Aug 13, 2007 at 03:52:54PM -0700, Christoph Lameter wrote: > On Tue, 14 Aug 2007, Andi Kleen wrote: > > > > I am not sure what you mean by that. Ia64 ZONE_DMA == x86_84 ZONE_DMA32? > > > > Hmm, when I wrote GFP_DMA32 it was a #define GFP_DMA32 GFP_DMA > > on ia64 so that drivers not need to ifdef. Someone nasty > > seems to have removed that too. I guess it would be best > > to readd. > > What would be the point? "so that drivers not need to ifdef" > > But then it wouldn't make sense to have GFP_DMA on ia64 and GFP_DMA32 > > on x86. Since driver writers are more likely to test on x86 > > I would recommend ia64 having compatible semantics. It'll > > save everybody trouble long term. This means it wouldn't > > help on IA64 machines that don't have a DMA zone -- they > > would still need to validate drivers especially -- but at least > > the others. > > There are no compatible semantics. ZONE_DMA may mean something different Yes current GFP_DMA is a mess. But GFP_DMA32 is relatively clean and it means that same as GFP_DMA on IA64. So ia64 could relatively painless switch to it. Anyways, I must admit ia64 is not my main concern. If you or Tony don't like GFP_DMA32 then keep using GFP_DMA if you want, but just don't complain about driver porting problems. I'm just trying to make your lives easier (that is why i did the #define originally), not be annoying. > for each arch depending on its need. An arch may not have a need for a 4GB > boundary (such as s390). I don't worry about s390 too much because the s390 driver universe doesn't really overlap with the x86 driver universe. So whatever semantics they have it's their own issue. If they ever build s390s with PCI slots that can take arbitary card they might have an issue, but I won't worry about this. -Andi - 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/