From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754352Ab2EHRWq (ORCPT ); Tue, 8 May 2012 13:22:46 -0400 Received: from mail-wg0-f44.google.com ([74.125.82.44]:42392 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754131Ab2EHRWo (ORCPT ); Tue, 8 May 2012 13:22:44 -0400 Date: Tue, 8 May 2012 19:23:52 +0200 From: Daniel Vetter To: Linus Torvalds , rob.clark@linaro.org Cc: =?iso-8859-1?Q?St=E9phane?= Marchesin , olofj@chromium.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH] mm: Work around Intel SNB GTT bug with some physical pages. Message-ID: <20120508172352.GQ4802@phenom.ffwll.local> Mail-Followup-To: Linus Torvalds , rob.clark@linaro.org, =?iso-8859-1?Q?St=E9phane?= Marchesin , olofj@chromium.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org References: <1336432421-17972-1-git-send-email-marcheu@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Operating-System: Linux phenom 3.4.0-rc3+ User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 08, 2012 at 08:25:38AM -0700, Linus Torvalds wrote: > On Mon, May 7, 2012 at 4:13 PM, Stéphane Marchesin wrote: > > > > In the end, I came up with the ugly workaround of just leaking the > > offending pages in shmem.c. > > Don't leak it. > > Instead, add it to some RCU list, and free it using RCU. Or some > one-second timer or something. > > That kind of approach should guarantee that it > > (a) gets returned to the system > > but > > (b) the returning to the system gets delayed sufficiently that if the > i915 driver is doing lots of allocations it will be getting other > pages. > > Hmm? The problem is also that this only affects Sandybdrige gpus, so we'd need to funnel this down to shmfs somehow ... Rob Clarke from Linaro will be working on a gemfs to make backing storage allocation more flexible - they need that to support some arm gpus. That way round we wouldn't need to put some ugly drm/i915 stuff into core shmfs. Rob? -Daniel -- Daniel Vetter Mail: daniel@ffwll.ch Mobile: +41 (0)79 365 57 48