ttm_bo_mem_space
r = ttm_bo_mem_space(&(*bo_ptr)->tbo, &(*bo_ptr)->placement,
r = ttm_bo_mem_space(bo, &placement, &tmp, &ctx);
int ttm_bo_mem_space(struct ttm_buffer_object *bo,
ret = ttm_bo_mem_space(bo, &hop_placement, &hop_mem, ctx);
ret = ttm_bo_mem_space(bo, &placement, &evict_mem, ctx);
EXPORT_SYMBOL(ttm_bo_mem_space);