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;