UIDHASH_BITS       10 include/linux/user_namespace.h #define UIDHASH_SZ	(1 << UIDHASH_BITS)
UIDHASH_BITS       34 kernel/user.c  #define __uidhashfn(uid)	(((uid >> UIDHASH_BITS) + uid) & UIDHASH_MASK)