From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 14 Aug 2007 12:56:11 -0700 (PDT) From: Christoph Lameter 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: owner-linux-mm@kvack.org Return-Path: To: Andi Kleen Cc: Mel Gorman , Lee.Schermerhorn@hp.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org