From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com ([134.134.136.24]:20364 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751727AbdFOFvj (ORCPT ); Thu, 15 Jun 2017 01:51:39 -0400 From: Jani Nikula To: Eric Blau , stable@vger.kernel.org Cc: Chris Wilson , Michel Thierry , Mika Kuoppala , Joonas Lahtinen , =?utf-8?Q?Micha=C5=82?= Winiarski , Daniel Vetter , intel-gfx@lists.freedesktop.org Subject: Re: [Intel-gfx] [PATCH] drm/i915: Do not drop pagetables when empty In-Reply-To: <20170614170728.GA30101@eric-macbookpro.localdomain> References: <20170614170728.GA30101@eric-macbookpro.localdomain> Date: Thu, 15 Jun 2017 08:51:34 +0300 Message-ID: <87a859ztll.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: stable-owner@vger.kernel.org List-ID: On Wed, 14 Jun 2017, Eric Blau wrote: > Can the following patch please be included in the next stable release? > It looks like it was submitted previously by Daniel Vetter, but has not > been included in 4.11.y yet. Thanks. The previous submission would be [1]. Please reference that instead of resending patches with incomplete upstream references. Thank you. BR, Jani. [1] http://mid.mail-archive.com/20170526082906.8982-1-daniel.vetter@ffwll.ch > From 64b1d89f358df34701d92471b65f99f4eff1b384 Mon Sep 17 00:00:00 2001 > From: Chris Wilson > Date: Thu, 18 May 2017 11:00:15 +0100 > Subject: [PATCH] drm/i915: Do not drop pagetables when empty > MIME-Version: 1.0 > Content-Type: text/plain; charset=UTF-8 > Content-Transfer-Encoding: 8bit > > Due to a race with the shrinker, when we try to allocate a pagetable, we > may end up shrinking it instead. This comes as a nasty surprise as we > try to dereference it to fill in the pagetable entries for the object. > > In linus/master this is fixed by pinning the pagetables prior to > allocation, but that backport is roughly > drivers/gpu/drm/i915/i915_debugfs.c | 2 +- > drivers/gpu/drm/i915/i915_gem_evict.c | 12 +- > drivers/gpu/drm/i915/i915_gem_gtt.c | 2017 ++++++++++++++------------------- > drivers/gpu/drm/i915/i915_gem_gtt.h | 123 +- > drivers/gpu/drm/i915/i915_trace.h | 104 -- > drivers/gpu/drm/i915/i915_vgpu.c | 9 +- > drivers/gpu/drm/i915/i915_vma.c | 9 - > drivers/gpu/drm/i915/intel_lrc.c | 4 +- > 8 files changed, 946 insertions(+), 1334 deletions(-) > i.e. unsuitable for stable. Instead we neuter the code that tried to > free the pagetables. > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99295 > Fixes: 2ce5179fe826 ("drm/i915/gtt: Free unused lower-level page tables") > Signed-off-by: Chris Wilson > Cc: Michel Thierry > Cc: Mika Kuoppala > Cc: Chris Wilson > Cc: Joonas Lahtinen > Cc: Michał Winiarski > Cc: Daniel Vetter > Cc: Jani Nikula > Cc: intel-gfx@lists.freedesktop.org > Cc: # v4.10+ > --- > drivers/gpu/drm/i915/i915_gem_gtt.c | 10 ---------- > 1 file changed, 10 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c > index 96e45a4d5441..4f581adf2fcf 100644 > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c > @@ -755,10 +755,6 @@ static bool gen8_ppgtt_clear_pt(struct i915_address_space *vm, > GEM_BUG_ON(pte_end > GEN8_PTES); > > bitmap_clear(pt->used_ptes, pte, num_entries); > - if (USES_FULL_PPGTT(vm->i915)) { > - if (bitmap_empty(pt->used_ptes, GEN8_PTES)) > - return true; > - } > > pt_vaddr = kmap_px(pt); > > @@ -798,9 +794,6 @@ static bool gen8_ppgtt_clear_pd(struct i915_address_space *vm, > } > } > > - if (bitmap_empty(pd->used_pdes, I915_PDES)) > - return true; > - > return false; > } > > @@ -829,9 +822,6 @@ static bool gen8_ppgtt_clear_pdp(struct i915_address_space *vm, > > mark_tlbs_dirty(ppgtt); > > - if (bitmap_empty(pdp->used_pdpes, I915_PDPES_PER_PDP(dev_priv))) > - return true; > - > return false; > } > > -- Jani Nikula, Intel Open Source Technology Center