PFFRAG_FRENT_HIWAT
pf->limit[PF_LIMIT_FRAGS] = PFFRAG_FRENT_HIWAT;
V_pf_limits[PF_LIMIT_FRAGS].limit = PFFRAG_FRENT_HIWAT;
uma_zone_set_max(V_pf_frent_z, PFFRAG_FRENT_HIWAT);