hfsc_class_qlength
if (hfsc_class_qlength(cl) == 0)
sp->qlength = hfsc_class_qlength(cl);
KASSERT(hfsc_class_qlength(cl) == 0);
if (dm != m && hfsc_class_qlength(cl) == 1) {
if (hfsc_class_qlength(cl) > 0) {