MAP_HUGE_MASK
hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
(flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
#define MAP_HUGE_PAGE_SIZE(x) (1ULL << ((x >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))
flags |= (shift & MAP_HUGE_MASK) << MAP_HUGE_SHIFT;