Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964969AbWIWAYL (ORCPT ); Fri, 22 Sep 2006 20:24:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964970AbWIWAYL (ORCPT ); Fri, 22 Sep 2006 20:24:11 -0400 Received: from omx2-ext.sgi.com ([192.48.171.19]:41667 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S964969AbWIWAYJ (ORCPT ); Fri, 22 Sep 2006 20:24:09 -0400 Date: Fri, 22 Sep 2006 17:23:54 -0700 (PDT) From: Christoph Lameter To: Andi Kleen cc: Martin Bligh , Alan Cox , akpm@google.com, linux-kernel@vger.kernel.org, Christoph Hellwig , James Bottomley , linux-mm@kvack.org Subject: Re: More thoughts on getting rid of ZONE_DMA In-Reply-To: <200609230134.45355.ak@suse.de> Message-ID: References: <4514441E.70207@mbligh.org> <200609230134.45355.ak@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: 1216 Lines: 26 On Sat, 23 Sep 2006, Andi Kleen wrote: > The problem is that if someone has a workload with lots of pinned pages > (e.g. lots of mlock) then the first 16MB might fill up completely and there > is no chance at all to free it because it's pinned Ok. That may be a problem for i386. After the removal of the GFP_DMA and ZONE_DMA stuff it is then be possible to redefine ZONE_DMA (or whatever we may call it ZONE_RESERVE?) to an arbitrary size a the beginning of memory. Then alloc_pages_range() can dynamically decide to tap that pool if necessary. I already have checks for ZONE_DMA and ZONE_DMA32 in there. If we just rename those then what you wanted would be there. If additional memory pools are available then they are used if the allocation restrictions fit to avoid a lengthy search. This may mean that i386 and x86_64 will still have two zones. Its somewhat better. However, on IA64 we would not need this since our DMA limit has been 4GB in the past. - 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/