MAP_HUGE_SHIFT
hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
(flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
extra |= MAP_HUGETLB | (page_shift << MAP_HUGE_SHIFT);
#define MAP_HUGE_PAGE_SIZE(x) (1ULL << ((x >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))
flags |= __builtin_ctzll(hugetlbsize) << MAP_HUGE_SHIFT;
flags |= (shift & MAP_HUGE_MASK) << MAP_HUGE_SHIFT;
int arg = ilog2(ps) << MAP_HUGE_SHIFT;
flags |= __builtin_ctzll(size) << MAP_HUGE_SHIFT;