Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933192AbXHNT4W (ORCPT ); Tue, 14 Aug 2007 15:56:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759702AbXHNT4N (ORCPT ); Tue, 14 Aug 2007 15:56:13 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:42283 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757692AbXHNT4M (ORCPT ); Tue, 14 Aug 2007 15:56:12 -0400 Date: Tue, 14 Aug 2007 12:56:11 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Andi Kleen cc: 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 In-Reply-To: <20070814002635.GR3406@bingen.suse.de> Message-ID: 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> <20070814002635.GR3406@bingen.suse.de> 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 Content-Length: 924 Lines: 25 On Tue, 14 Aug 2007, Andi Kleen wrote: > > 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. Right. That is the point of the function. It isolates these strange platform dependencies. That is why there is no need for ZONE_DMA32 on any other platform. - 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/