From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: Radical idea Date: Sun, 17 Sep 2006 20:13:27 +0200 References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200609172013.27095.ak@suse.de> Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: pj@sgi.com, linux-mm@kvack.org, akpm@osdl.org List-ID: > > And yes it would only work the DMA32 problems mentioned by Andi could be > addressed. Do we really need DMA32 in modern systems with IOMMUs? We do. In fact we still need DMA-without-32 on most systems (after all most users still want to use their floppy occasionally and it is needed for a few other devices too) > Isnt this a transitionary problem that will go away? Not any time soon. > So lets say we have one of those systems without IOMMU. Then we only have > a problem for a class of NUMA systems that have: > > 1. Memory beyond 4GB > > and > > 2. Per node memory less than 4GB. Otherwise DMA32 is only on node 0. > > Isnt this a fairly small group of systems? I don't think so. e.g. a lot of quad opteron configurations come with 1 or 2GB per socket (= node) Anyways, even if it was uncommon we couldn't just break it. So i'm not sure what the point of your "popularity contest" is? -Andi -- 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