TPACTIVE
if ((sc->flags & (TPACTIVE | TPREW | TPRMARK | TPWMARK)) == 0)
if (sc->flags & (TPACTIVE | TPREW | TPRMARK | TPWMARK))
if ((sc->flags & TPACTIVE) == 0) {
sc->flags &= ~TPACTIVE;
while (sc->flags & (TPACTIVE | TPREW | TPRMARK | TPWMARK))
sc->flags |= TPACTIVE;
callout_reset(&sc->sc_timer_ch, (sc->flags & TPACTIVE) ? 1 : hz,