Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S939561AbXHMXcv (ORCPT ); Mon, 13 Aug 2007 19:32:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S936419AbXHMXc3 (ORCPT ); Mon, 13 Aug 2007 19:32:29 -0400 Received: from ns2.suse.de ([195.135.220.15]:47948 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757900AbXHMXc0 (ORCPT ); Mon, 13 Aug 2007 19:32:26 -0400 Date: Tue, 14 Aug 2007 02:26:35 +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: <20070814002635.GR3406@bingen.suse.de> References: <20070813225841.GG3406@bingen.suse.de> <20070813230801.GH3406@bingen.suse.de> <20070813234322.GJ3406@bingen.suse.de> <20070814000041.GL3406@bingen.suse.de> <20070814001659.GP3406@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: 971 Lines: 30 On Mon, Aug 13, 2007 at 04:27:42PM -0700, Christoph Lameter wrote: > On Tue, 14 Aug 2007, Andi Kleen wrote: > > > > Ok then lets do it. > > > > Conversion only makes sense once an API with a explicit mask > > is in. Otherwise we have muddled semantics again. > > pci_set_consistent_dma_mask > > has that. While on x86 it is roughly identical (although the low level allocator is currently not very reliable) it makes a significant difference on some platforms. e.g. I was told on PA-RISC consistent memory is much more costly than non consistent ones. That's probably true on anything that's not full IO cache consistent. So while it would be reasonable semantics for x86 and IA64 it's not for everybody else. -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/