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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2017-08-04 11:41:35 +0100 |
|---|---|---|
| committer | Jani Nikula <jani.nikula@intel.com> | 2017-08-07 13:38:56 +0300 |
| commit | cd82f37a9ddaaafb33d8bc3f44857edbad5d52bf (patch) | |
| tree | fe4ac7530bfd8cde14873c3844aa29f04890e4f0 | |
| parent | b5fa57ddc4a2492441a1391f07d5c8a282271249 (diff) | |
| download | linux-cd82f37a9ddaaafb33d8bc3f44857edbad5d52bf.tar.gz | |
drm/i915/shrinker: Wrap need_resched() inside preempt-disable
In order for us to successfully detect the end of a timeslice,
preemption must be disabled. Otherwise, inside the loop we may be
preempted many times without our noticing, and each time our timeslice
will be reset, invalidating need_resched()
Reported-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reported-by: Tomi Sarvela <tomi.p.sarvela@intel.com>
Fixes: 290271de34f6 ("drm/i915: Spin for struct_mutex inside shrinker")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <drm-intel-fixes@lists.freedesktop.org> # v4.13-rc1+
Link: https://patchwork.freedesktop.org/patch/msgid/20170804104135.26805-1-chris@chris-wilson.co.uk
Tested-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
(cherry picked from commit 6cb0c6ad9e07f2c7971c4e8e0d9b7ceba151a925)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem_shrinker.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c index 1032f98add112..77fb398081314 100644 --- a/drivers/gpu/drm/i915/i915_gem_shrinker.c +++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c @@ -43,16 +43,21 @@ static bool shrinker_lock(struct drm_i915_private *dev_priv, bool *unlock) return true; case MUTEX_TRYLOCK_FAILED: + *unlock = false; + preempt_disable(); do { cpu_relax(); if (mutex_trylock(&dev_priv->drm.struct_mutex)) { - case MUTEX_TRYLOCK_SUCCESS: *unlock = true; - return true; + break; } } while (!need_resched()); + preempt_enable(); + return *unlock; - return false; + case MUTEX_TRYLOCK_SUCCESS: + *unlock = true; + return true; } BUG(); |