This is a note to let you know that I've just added the patch titled
drm/i915: Do not drop pagetables when empty
to the 4.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-i915-do-not-drop-pagetables-when-empty.patch
and it can be found in the queue-4.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From daniel.vetter@xxxxxxxx Thu Jun 15 08:32:03 2017
From: Daniel Vetter <daniel.vetter@xxxxxxxx>
Date: Fri, 26 May 2017 10:29:06 +0200
Subject: drm/i915: Do not drop pagetables when empty
To: Intel Graphics Development <intel-gfx@xxxxxxxxxxxxxxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>, Michel Thierry <michel.thierry@xxxxxxxxx>, Mika Kuoppala <mika.kuoppala@xxxxxxxxx>, Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>, Michał Winiarski <michal.winiarski@xxxxxxxxx>, Daniel Vetter <daniel.vetter@xxxxxxxxx>, Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>, "# v4 . 10+" <stable@xxxxxxxxxxxxxxx>
Message-ID: <20170526082906.8982-1-daniel.vetter@xxxxxxxx>
From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
This is the minimal backport for stable of the upstream commit:
commit dd19674bacba227ae5d3ce680cbc5668198894dc
Author: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Date: Wed Feb 15 08:43:46 2017 +0000
drm/i915: Remove bitmap tracking for used-ptes
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_gem_gtt.c | 10 ----------
1 file changed, 10 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 <chris@xxxxxxxxxxxxxxxxxx>
Cc: Michel Thierry <michel.thierry@xxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Michał Winiarski <michal.winiarski@xxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # v4.10+
Tested-by: Maël Lavault <mael.lavault@xxxxxxxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
--- 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 i
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 i
}
}
- if (bitmap_empty(pd->used_pdes, I915_PDES))
- return true;
-
return false;
}
@@ -829,9 +822,6 @@ static bool gen8_ppgtt_clear_pdp(struct
mark_tlbs_dirty(ppgtt);
- if (bitmap_empty(pdp->used_pdpes, I915_PDPES_PER_PDP(dev_priv)))
- return true;
-
return false;
}
Patches currently in stable-queue which might be from daniel.vetter@xxxxxxxx are
queue-4.11/drm-i915-do-not-drop-pagetables-when-empty.patch