From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761232AbZE0RkV (ORCPT ); Wed, 27 May 2009 13:40:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757070AbZE0RkN (ORCPT ); Wed, 27 May 2009 13:40:13 -0400 Received: from 69-30-77-85.dq1sn.easystreet.com ([69.30.77.85]:47739 "EHLO kingsolver.anholt.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756021AbZE0RkM (ORCPT ); Wed, 27 May 2009 13:40:12 -0400 Subject: Re: [PATCH] drm: i915: ensure objects are allocated below 4GB on PAE From: Eric Anholt To: Shaohua Li Cc: Kyle McMartin , Hugh Dickins , "airlied@redhat.com" , "dri-devel@lists.sf.net" , "linux-kernel@vger.kernel.org" , "jbarnes@virtuousgeek.org" , "stable@kernel.org" , "linux-mm@kvack.org" In-Reply-To: <20090527004250.GA11835@sli10-desk.sh.intel.com> References: <20090526162717.GC14808@bombadil.infradead.org> <20090527001840.GC16929@bombadil.infradead.org> <20090527004250.GA11835@sli10-desk.sh.intel.com> Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-gVhHpGaJA1/89bQ8nK4v" Date: Wed, 27 May 2009 10:40:12 -0700 Message-Id: <1243446012.8400.37.camel@gaiman.anholt.net> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-gVhHpGaJA1/89bQ8nK4v Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Wed, 2009-05-27 at 08:42 +0800, Shaohua Li wrote: > On Wed, May 27, 2009 at 08:18:40AM +0800, Kyle McMartin wrote: > > On Tue, May 26, 2009 at 11:55:50PM +0100, Hugh Dickins wrote: > > > I'm confused: I thought GFP_DMA32 only applies on x86_64: > > > my 32-bit PAE machine with (slightly!) > 4GB shows no ZONE_DMA32. > > > Does this patch perhaps depend on another, to enable DMA32 on 32-bit > > > PAE, or am I just in a muddle? > > >=20 > >=20 > > No, you're exactly right, I'm just a muppet and missed the obvious. > > Looks like the "correct" fix is the fact that the allocation is thus > > filled out with GFP_USER, therefore, from ZONE_NORMAL, and below > > max_low_pfn. > >=20 > > Looks like we'll need some additional thinking to get true ZONE_DMA32 o= n > > i386... ugh, I'll look into it tonight. > For i386, GFP_USER is enough. But 945G GART can only map to physical page= < 4G, > so for x64, we need GFP_DMA32. This is the reason I add extra GFP_DMA32. Those 945Gs don't have memory located above 4G, from my reading of the chipset specs. --=20 Eric Anholt eric@anholt.net eric.anholt@intel.com --=-gVhHpGaJA1/89bQ8nK4v Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEABECAAYFAkodevwACgkQHUdvYGzw6vcEngCgjb9B+8tpQB4CH1x/3rE63frA H9wAn06Mh1ljZtMcAFVVbstunBWdz18J =hwZx -----END PGP SIGNATURE----- --=-gVhHpGaJA1/89bQ8nK4v--