Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755323AbYHTVQR (ORCPT ); Wed, 20 Aug 2008 17:16:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752048AbYHTVQE (ORCPT ); Wed, 20 Aug 2008 17:16:04 -0400 Received: from smtpq2.groni1.gr.home.nl ([213.51.130.201]:60774 "EHLO smtpq2.groni1.gr.home.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752005AbYHTVQD (ORCPT ); Wed, 20 Aug 2008 17:16:03 -0400 Message-ID: <48AC89C8.1040804@keyaccess.nl> Date: Wed, 20 Aug 2008 23:16:56 +0200 From: Rene Herman User-Agent: Thunderbird 2.0.0.16 (X11/20080707) MIME-Version: 1.0 To: Dave Airlie CC: Ingo Molnar , Venki Pallipadi , "Li, Shaohua" , Yinghai Lu , Andreas Herrmann , Arjan van de Ven , "dri-users@lists.sourceforge.net" , Linux Kernel , "Siddha, Suresh B" , Thomas Gleixner , "H. Peter Anvin" , Dave Jones Subject: Re: AGP and PAT (induced?) problem (on AMD family 6) References: <48972EA8.8040001@keyaccess.nl> <20080815142218.GC12954@elte.hu> <48A59FAC.7050605@keyaccess.nl> <48AA9C3B.5030309@keyaccess.nl> <20080819102633.GE6722@elte.hu> <48AAD680.7020508@keyaccess.nl> <20080819190757.GA17470@linux-os.sc.intel.com> <20080820100440.GE28492@elte.hu> <48ABF6DC.8070305@keyaccess.nl> <21d7e9970808201402n4d7f5f18waba0685636bb51bf@mail.gmail.com> In-Reply-To: <21d7e9970808201402n4d7f5f18waba0685636bb51bf@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -1.0 (-) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1614 Lines: 43 On 20-08-08 23:02, Dave Airlie wrote: > On Wed, Aug 20, 2008 at 8:50 PM, Rene Herman > wrote: >> On 20-08-08 12:04, Ingo Molnar wrote: >> >>> * Venki Pallipadi wrote: >>> >>>>> I'd really like a reply from the AGP or PAT side right about >>>>> now. >>>> Hmm. Looks like there are more than 16000 entries in the PAT >>>> list! >>> hm, btw., why is that? >> Because 64M of AGP memory divided by 4K pages is 16K. That is, the >> underlying problem seems to be AGP drivers using order 0 >> allocations. I'm looking. [ ... ] > I haven't anything to add, I'm the maintainer not the author, all the > people who wrote the offending code were already involved. The underlying problem is the order 0 allocations (agp_allocate_memory --> agp_generic_allocate_page) where each single page is set uncached individually, creating a PAT entry. Non order 0 allocations generally would ofcourse help. That's very much AGP internal -- do you feel that's the way to go? All the current AGP drivers except sgi-agp use agp_generic_alloc_page(). Doing a quick local hack to collect pages in agp_allocate_memory() into regions and set the regions (generally 1) UC in one fell swoop, but I don't know if that's safe (and it feels like a rather poor hack anyway). (not to mention that it's time for bed again). Rene. -- 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/