FRAC_BITS
#define ONE_FP (1UL << FRAC_BITS)
#define QFQ_MIN_SLOT_SHIFT (FRAC_BITS + QFQ_MTU_SHIFT - QFQ_MAX_INDEX)
grp->slot_shift = QFQ_MTU_SHIFT + FRAC_BITS -
#ifndef FRAC_BITS
#define ONE_FP (1UL << FRAC_BITS)