PAGE_SECTION_MASK 1077 include/linux/mmzone.h #define SECTION_ALIGN_UP(pfn)	(((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK)
PAGE_SECTION_MASK 1078 include/linux/mmzone.h #define SECTION_ALIGN_DOWN(pfn)	((pfn) & PAGE_SECTION_MASK)