drm/i915/shrinker: Wrap need_resched() inside preempt-disable
authorChris Wilson <chris@chris-wilson.co.uk>
Fri, 4 Aug 2017 10:41:35 +0000 (11:41 +0100)
committerChris Wilson <chris@chris-wilson.co.uk>
Fri, 4 Aug 2017 12:11:39 +0000 (13:11 +0100)
commit6cb0c6ad9e07f2c7971c4e8e0d9b7ceba151a925
tree966c32e57fe65d6b69b35952e3816eda312ed33d
parent28152a238bb60d2577b9d4e7172a83bf4c1bf047
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>
drivers/gpu/drm/i915/i915_gem_shrinker.c