drm/i915: Improve lockdep tracking for obj->mm.lock

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The shrinker may appear to recurse into obj->mm.lock as the shrinker may
be called from a direct reclaim path whilst handling get_pages. We
filter out recursing on the same obj->mm.lock by inspecting
obj->mm.pages, but we do want to take the lock on a second object in
order to reap their pages. lockdep spots the recursion on the same
lockclass and needs annotation to avoid a false positive. To keep the
two paths distinct, create an enum to indicate which subclass of
obj->mm.lock we are using. This removes the false positive and avoids
masking real bugs.

Suggested-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161101121134.27504-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

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This commit is contained in:

Chris Wilson 2016-11-01 12:11:34 +00:00

parent db6c2b4151

commit 548625ee8f

4 changed files with 15 additions and 8 deletions

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8

drivers/gpu/drm/i915/i915_drv.h

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9

drivers/gpu/drm/i915/i915_gem.c

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4

drivers/gpu/drm/i915/i915_gem_shrinker.c

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2

drivers/gpu/drm/i915/i915_gem_userptr.c

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