compound_idx     1442 mm/hugetlb.c   	unsigned long compound_idx;
compound_idx     1448 mm/hugetlb.c   		compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
compound_idx     1450 mm/hugetlb.c   		compound_idx = page - page_head;
compound_idx     1452 mm/hugetlb.c   	return (index << compound_order(page_head)) + compound_idx;