It can be quite big, and there's no need for it to be physically
contiguous. This is less likely to fail under memory pressure (has
actually happened while running piglit).

Cc: stable@vger.kernel.org
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>