xas_try_split_min_order
unsigned int xas_try_split_min_order(unsigned int order);
EXPORT_SYMBOL_GPL(xas_try_split_min_order);
xas_try_split_min_order(order));
max(xas_try_split_min_order(
split_order = xas_try_split_min_order(cur_order);
split_order = xas_try_split_min_order(split_order);