In place of true activity counting, we walk the list of vma associated
with an object managing each on the vm's active/inactive list everytime
we call move-to-inactive. This depends upon the vma->mm_list being
cleared after unbinding, or else we run into difficulty when tracking
the object in multiple vm's - we see a use-after free and corruption of
the mm_list.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Ben Widawsky <ben@bwidawsk.net> Reviewed-by: Ben Widawsky <ben@bwidawsk.net> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>