- Implement selwakeuppri() which allows raising the priority of a

  thread being waken up.  The thread waken up can run at a priority as
  high as after tsleep().

- Replace selwakeup()s with selwakeuppri()s and pass appropriate
  priorities.

- Add cv_broadcastpri() which raises the priority of the broadcast
  threads.  Used by selwakeuppri() if collision occurs.

Not objected in:	-arch, -current

52 files changed, 105 insertions, 74 deletions

diff --git a/sys/cam/scsi/scsi_target.c b/sys/cam/scsi/scsi_target.c
index d9cfdc3..749447f 100644
--- a/sys/cam/scsi/scsi_target.c
+++ b/sys/cam/scsi/scsi_target.c
@@ -1119,7 +1119,7 @@ notify_user(struct targ_softc *softc)
 	 * Notify users sleeping via poll(), kqueue(), and
 	 * blocking read().
 	 */
-	selwakeup(&softc->read_select);
+	selwakeuppri(&softc->read_select, PRIBIO);
 	KNOTE(&softc->read_select.si_note, 0);
 	wakeup(&softc->user_ccb_queue);
 }
diff --git a/sys/coda/coda_psdev.c b/sys/coda/coda_psdev.c
index debbdbf..133d0fd 100644
--- a/sys/coda/coda_psdev.c
+++ b/sys/coda/coda_psdev.c
@@ -526,7 +526,7 @@ coda_call(mntinfo, inSize, outSize, buffer)
 
 	/* Append msg to request queue and poke Venus. */
 	INSQUE(vmp->vm_chain, vcp->vc_requests);
-	selwakeup(&(vcp->vc_selproc));
+	selwakeuppri(&(vcp->vc_selproc), coda_call_sleep);
 
 	/* We can be interrupted while we wait for Venus to process
 	 * our request.  If the interrupt occurs before Venus has read
@@ -664,7 +664,7 @@ coda_call(mntinfo, inSize, outSize, buffer)
 		
 		/* insert at head of queue! */
 		INSQUE(svmp->vm_chain, vcp->vc_requests);
-		selwakeup(&(vcp->vc_selproc));
+		selwakeuppri(&(vcp->vc_selproc), coda_call_sleep);
 	    }
 	}
 
diff --git a/sys/dev/aac/aac.c b/sys/dev/aac/aac.c
index 8466bd8..bb54691 100644
--- a/sys/dev/aac/aac.c
+++ b/sys/dev/aac/aac.c
@@ -2717,7 +2717,7 @@ aac_handle_aif(struct aac_softc *sc, struct aac_fib *fib)
 		if (sc->aac_state & AAC_STATE_AIF_SLEEPER)
 			wakeup(sc->aac_aifq);
 		/* Wakeup any poll()ers */
-		selwakeup(&sc->rcv_select);
+		selwakeuppri(&sc->rcv_select, PRIBIO);
 	}
 	AAC_LOCK_RELEASE(&sc->aac_aifq_lock);
 
diff --git a/sys/dev/atkbdc/psm.c b/sys/dev/atkbdc/psm.c
index ef98da4..2c14bbe 100644
--- a/sys/dev/atkbdc/psm.c
+++ b/sys/dev/atkbdc/psm.c
@@ -2371,7 +2371,7 @@ psmintr(void *arg)
             sc->state &= ~PSM_ASLP;
             wakeup( sc);
     	}
-        selwakeup(&sc->rsel);
+        selwakeuppri(&sc->rsel, PZERO);
     }
 }
 
diff --git a/sys/dev/bktr/bktr_core.c b/sys/dev/bktr/bktr_core.c
index 19795a2..b9d21b8 100644
--- a/sys/dev/bktr/bktr_core.c
+++ b/sys/dev/bktr/bktr_core.c
@@ -821,7 +821,7 @@ common_bktr_intr( void *arg )
 
 		/* If someone has a select() on /dev/vbi, inform them */
 		if (SEL_WAITING(&bktr->vbi_select)) {
-			selwakeup(&bktr->vbi_select);
+			selwakeuppri(&bktr->vbi_select, VBIPRI);
 		}
 
 
diff --git a/sys/dev/firewire/firewire.c b/sys/dev/firewire/firewire.c
index be01cc4..9844e7b 100644
--- a/sys/dev/firewire/firewire.c
+++ b/sys/dev/firewire/firewire.c
@@ -1963,7 +1963,7 @@ fw_rcv(struct fw_rcv_buf *rb)
 #else
 		if (&xferq->rsel.si_pid != 0)
 #endif
-			selwakeup(&xferq->rsel);
+			selwakeuppri(&xferq->rsel, FWPRI);
 		if (xferq->flag & FWXFERQ_WAKEUP) {
 			xferq->flag &= ~FWXFERQ_WAKEUP;
 			wakeup((caddr_t)xferq);
diff --git a/sys/dev/kbd/kbd.c b/sys/dev/kbd/kbd.c
index 1e8785d..f5dd583 100644
--- a/sys/dev/kbd/kbd.c
+++ b/sys/dev/kbd/kbd.c
@@ -676,7 +676,7 @@ genkbd_event(keyboard_t *kbd, int event, void *arg)
 			sc->gkb_flags &= ~KB_ASLEEP;
 			wakeup(sc);
 		}
-		selwakeup(&sc->gkb_rsel);
+		selwakeuppri(&sc->gkb_rsel, PZERO);
 		return 0;
 	default:
 		return EINVAL;
@@ -747,7 +747,7 @@ genkbd_event(keyboard_t *kbd, int event, void *arg)
 			sc->gkb_flags &= ~KB_ASLEEP;
 			wakeup(sc);
 		}
-		selwakeup(&sc->gkb_rsel);
+		selwakeuppri(&sc->gkb_rsel, PZERO);
 	}
 
 	return 0;
diff --git a/sys/dev/mse/mse.c b/sys/dev/mse/mse.c
index bb79f28..408bbf7 100644
--- a/sys/dev/mse/mse.c
+++ b/sys/dev/mse/mse.c
@@ -751,7 +751,7 @@ mseintr(arg)
 			sc->sc_flags &= ~MSESC_WANT;
 			wakeup(sc);
 		}
-		selwakeup(&sc->sc_selp);
+		selwakeuppri(&sc->sc_selp, MSEPRI);
 	}
 }
 
diff --git a/sys/dev/nmdm/nmdm.c b/sys/dev/nmdm/nmdm.c
index 1511e9b..3227b11 100644
--- a/sys/dev/nmdm/nmdm.c
+++ b/sys/dev/nmdm/nmdm.c
@@ -451,11 +451,11 @@ wakeup_other(struct tty *tp, int flag)
 
 	GETPARTS(tp, ourpart, otherpart);
 	if (flag & FREAD) {
-		selwakeup(&otherpart->nm_tty.t_rsel);
+		selwakeuppri(&otherpart->nm_tty.t_rsel, TTIPRI);
 		wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
 	}
 	if (flag & FWRITE) {
-		selwakeup(&otherpart->nm_tty.t_wsel);
+		selwakeuppri(&otherpart->nm_tty.t_wsel, TTOPRI);
 		wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
 	}
 }
diff --git a/sys/dev/random/randomdev.c b/sys/dev/random/randomdev.c
index 6bbe200..48618e9 100644
--- a/sys/dev/random/randomdev.c
+++ b/sys/dev/random/randomdev.c
@@ -426,7 +426,7 @@ random_unblock(void)
 {
 	if (!random_systat.seeded) {
 		random_systat.seeded = 1;
-		selwakeup(&random_systat.rsel);
+		selwakeuppri(&random_systat.rsel, PUSER);
 		wakeup(&random_systat);
 	}
 }
diff --git a/sys/dev/sab/sab.c b/sys/dev/sab/sab.c
index 2eeb7f0..d8ac3d4 100644
--- a/sys/dev/sab/sab.c
+++ b/sys/dev/sab/sab.c
@@ -799,7 +799,7 @@ sabttystart(struct tty *tp)
 			tp->t_state &= ~TS_SO_OLOWAT;
 			wakeup(TSA_OLOWAT(tp));
 		}
-		selwakeup(&tp->t_wsel);
+		selwakeuppri(&tp->t_wsel, TTOPRI);
 		if (tp->t_outq.c_cc == 0) {
 			if ((tp->t_state & (TS_BUSY | TS_SO_OCOMPLETE)) ==
 			    TS_SO_OCOMPLETE && tp->t_outq.c_cc == 0) {
diff --git a/sys/dev/snp/snp.c b/sys/dev/snp/snp.c
index d08ff3f..4c4115d 100644
--- a/sys/dev/snp/snp.c
+++ b/sys/dev/snp/snp.c
@@ -370,7 +370,7 @@ snp_in(snp, buf, n)
 		snp->snp_flags &= ~SNOOP_RWAIT;
 		wakeup(snp);
 	}
-	selwakeup(&snp->snp_sel);
+	selwakeuppri(&snp->snp_sel, PZERO + 1);
 
 	return (n);
 }
@@ -444,7 +444,7 @@ snp_detach(snp)
 	snp->snp_target = NODEV;
 
 detach_notty:
-	selwakeup(&snp->snp_sel);
+	selwakeuppri(&snp->snp_sel, PZERO + 1);
 	if ((snp->snp_flags & SNOOP_OPEN) == 0) 
 		free(snp, M_SNP);
 
diff --git a/sys/dev/sound/midi/midibuf.c b/sys/dev/sound/midi/midibuf.c
index 8b4eda7..f444405 100644
--- a/sys/dev/sound/midi/midibuf.c
+++ b/sys/dev/sound/midi/midibuf.c
@@ -358,7 +358,7 @@ queuerawdata(midi_dbuf *dbuf, char *data, int len)
 	/* Wake up the processes sleeping on input data. */
 	cv_broadcast(&dbuf->cv_in);
 	if (SEL_WAITING(&dbuf->sel) && dbuf->rl >= dbuf->blocksize)
-		selwakeup(&dbuf->sel);
+		selwakeuppri(&dbuf->sel, PRIBIO);
 }
 
 static void
@@ -399,5 +399,5 @@ deleterawdata(midi_dbuf *dbuf, int len)
 	/* Wake up the processes sleeping on queueing. */
 	cv_broadcast(&dbuf->cv_out);
 	if (SEL_WAITING(&dbuf->sel) && dbuf->fl >= dbuf->blocksize)
-		selwakeup(&dbuf->sel);
+		selwakeuppri(&dbuf->sel, PRIBIO);
 }
diff --git a/sys/dev/sound/pcm/channel.c b/sys/dev/sound/pcm/channel.c
index c17b219..7a1c906 100644
--- a/sys/dev/sound/pcm/channel.c
+++ b/sys/dev/sound/pcm/channel.c
@@ -116,7 +116,7 @@ chn_wakeup(struct pcm_channel *c)
 
 	CHN_LOCKASSERT(c);
 	if (SEL_WAITING(sndbuf_getsel(bs)) && chn_polltrigger(c))
-		selwakeup(sndbuf_getsel(bs));
+		selwakeuppri(sndbuf_getsel(bs), PRIBIO);
 	wakeup(bs);
 }
 
diff --git a/sys/dev/usb/ucom.c b/sys/dev/usb/ucom.c
index b398661..a57d6f8 100644
--- a/sys/dev/usb/ucom.c
+++ b/sys/dev/usb/ucom.c
@@ -875,7 +875,7 @@ ucomstart(struct tty *tp)
 			CLR(tp->t_state, TS_SO_OLOWAT);
 			wakeup(TSA_OLOWAT(tp));
 		}
-		selwakeup(&tp->t_wsel);
+		selwakeuppri(&tp->t_wsel, TTIPRI);
 		if (tp->t_outq.c_cc == 0) {
 			if (ISSET(tp->t_state, TS_BUSY | TS_SO_OCOMPLETE) ==
 			    TS_SO_OCOMPLETE && tp->t_outq.c_cc == 0) {
diff --git a/sys/dev/usb/ugen.c b/sys/dev/usb/ugen.c
index bf73938..8740c3d 100644
--- a/sys/dev/usb/ugen.c
+++ b/sys/dev/usb/ugen.c
@@ -945,7 +945,7 @@ ugenintr(usbd_xfer_handle xfer, usbd_private_handle addr, usbd_status status)
 		DPRINTFN(5, ("ugen_intr: waking %p\n", sce));
 		wakeup(sce);
 	}
-	selwakeup(&sce->rsel);
+	selwakeuppri(&sce->rsel, PZERO);
 }
 
 Static void
@@ -1005,7 +1005,7 @@ ugen_isoc_rintr(usbd_xfer_handle xfer, usbd_private_handle addr,
 		DPRINTFN(5, ("ugen_isoc_rintr: waking %p\n", sce));
 		wakeup(sce);
 	}
-	selwakeup(&sce->rsel);
+	selwakeuppri(&sce->rsel, PZERO);
 }
 
 Static usbd_status
diff --git a/sys/dev/usb/uhid.c b/sys/dev/usb/uhid.c
index c61e4ba..2451542 100644
--- a/sys/dev/usb/uhid.c
+++ b/sys/dev/usb/uhid.c
@@ -383,7 +383,7 @@ uhid_intr(usbd_xfer_handle xfer, usbd_private_handle addr, usbd_status status)
 		DPRINTFN(5, ("uhid_intr: waking %p\n", &sc->sc_q));
 		wakeup(&sc->sc_q);
 	}
-	selwakeup(&sc->sc_rsel);
+	selwakeuppri(&sc->sc_rsel, PZERO);
 	if (sc->sc_async != NULL) {
 		DPRINTFN(3, ("uhid_intr: sending SIGIO %p\n", sc->sc_async));
 		PROC_LOCK(sc->sc_async);
diff --git a/sys/dev/usb/ums.c b/sys/dev/usb/ums.c
index f09fba7..dea1e0b 100644
--- a/sys/dev/usb/ums.c
+++ b/sys/dev/usb/ums.c
@@ -394,7 +394,7 @@ ums_detach(device_t self)
 	}
 	if (sc->state & UMS_SELECT) {
 		sc->state &= ~UMS_SELECT;
-		selwakeup(&sc->rsel);
+		selwakeuppri(&sc->rsel, PZERO);
 	}
 
 	destroy_dev(sc->dev);
@@ -533,7 +533,7 @@ ums_add_to_queue(struct ums_softc *sc, int dx, int dy, int dz, int buttons)
 	}
 	if (sc->state & UMS_SELECT) {
 		sc->state &= ~UMS_SELECT;
-		selwakeup(&sc->rsel);
+		selwakeuppri(&sc->rsel, PZERO);
 	}
 }
 Static int
diff --git a/sys/dev/usb/usb.c b/sys/dev/usb/usb.c
index 846a82f..dd2e2b3 100644
--- a/sys/dev/usb/usb.c
+++ b/sys/dev/usb/usb.c
@@ -810,7 +810,7 @@ usb_add_event(int type, struct usb_event *uep)
 	TAILQ_INSERT_TAIL(&usb_events, ueq, next);
 	usb_nevents++;
 	wakeup(&usb_events);
-	selwakeup(&usb_selevent);
+	selwakeuppri(&usb_selevent, PZERO);
 	if (usb_async_proc != NULL) {
 		PROC_LOCK(usb_async_proc);
 		psignal(usb_async_proc, SIGIO);
diff --git a/sys/dev/zs/zs.c b/sys/dev/zs/zs.c
index f3687ff..7e58049 100644
--- a/sys/dev/zs/zs.c
+++ b/sys/dev/zs/zs.c
@@ -600,7 +600,7 @@ zsttystart(struct tty *tp)
 			tp->t_state &= ~TS_SO_OLOWAT;
 			wakeup(TSA_OLOWAT(tp));
 		}
-		selwakeup(&tp->t_wsel);
+		selwakeuppri(&tp->t_wsel, TTOPRI);
 		if (tp->t_outq.c_cc == 0) {
 			if ((tp->t_state & (TS_BUSY | TS_SO_OCOMPLETE)) ==
 			    TS_SO_OCOMPLETE && tp->t_outq.c_cc == 0) {
diff --git a/sys/fs/coda/coda_psdev.c b/sys/fs/coda/coda_psdev.c
index debbdbf..133d0fd 100644
--- a/sys/fs/coda/coda_psdev.c
+++ b/sys/fs/coda/coda_psdev.c
@@ -526,7 +526,7 @@ coda_call(mntinfo, inSize, outSize, buffer)
 
 	/* Append msg to request queue and poke Venus. */
 	INSQUE(vmp->vm_chain, vcp->vc_requests);
-	selwakeup(&(vcp->vc_selproc));
+	selwakeuppri(&(vcp->vc_selproc), coda_call_sleep);
 
 	/* We can be interrupted while we wait for Venus to process
 	 * our request.  If the interrupt occurs before Venus has read
@@ -664,7 +664,7 @@ coda_call(mntinfo, inSize, outSize, buffer)
 		
 		/* insert at head of queue! */
 		INSQUE(svmp->vm_chain, vcp->vc_requests);
-		selwakeup(&(vcp->vc_selproc));
+		selwakeuppri(&(vcp->vc_selproc), coda_call_sleep);
 	    }
 	}
 
diff --git a/sys/i386/bios/apm.c b/sys/i386/bios/apm.c
index f67bdbe..64337c4 100644
--- a/sys/i386/bios/apm.c
+++ b/sys/i386/bios/apm.c
@@ -999,7 +999,7 @@ apm_record_event(struct apm_softc *sc, u_int event_type)
 	sc->event_ptr %= APM_NEVENTS;
 	evp->type = event_type;
 	evp->index = ++apm_evindex;
-	selwakeup(&sc->sc_rsel);
+	selwakeuppri(&sc->sc_rsel, PZERO);
 	return (sc->sc_flags & SCFLAG_OCTL) ? 0 : 1; /* user may handle */
 }
 
diff --git a/sys/i386/isa/asc.c b/sys/i386/isa/asc.c
index e304683..23a9801 100644
--- a/sys/i386/isa/asc.c
+++ b/sys/i386/isa/asc.c
@@ -525,7 +525,7 @@ ascintr(int unit)
 	    dma_restart(scu);
 	}
 	if (SEL_WAITING(&scu->selp)) {
-	    selwakeup(&scu->selp);
+	    selwakeuppri(&scu->selp, ASCPRI);
 	}
     }
 }
diff --git a/sys/i386/isa/cx.c b/sys/i386/isa/cx.c
index fd5b686..a2a4693 100644
--- a/sys/i386/isa/cx.c
+++ b/sys/i386/isa/cx.c
@@ -546,7 +546,7 @@ cxoproc (struct tty *tp)
 			tp->t_state &= ~TS_ASLEEP;
 			wakeup(TSA_OLOWAT(tp));
 		}
-		selwakeup(&tp->t_wsel);
+		selwakeuppri(&tp->t_wsel, TTOPRI);
 	}
 #endif
 	splx (s);
diff --git a/sys/i386/isa/istallion.c b/sys/i386/isa/istallion.c
index f9bea0c..7f27ad7 100644
--- a/sys/i386/isa/istallion.c
+++ b/sys/i386/isa/istallion.c
@@ -1709,7 +1709,7 @@ static void stli_start(struct tty *tp)
 			tp->t_state &= ~TS_ASLEEP;
 			wakeup(&tp->t_outq);
 		}
-		selwakeup(&tp->t_wsel);
+		selwakeuppri(&tp->t_wsel, TTOPRI);
 	}
 #endif
 
diff --git a/sys/i386/isa/mse.c b/sys/i386/isa/mse.c
index bb79f28..408bbf7 100644
--- a/sys/i386/isa/mse.c
+++ b/sys/i386/isa/mse.c
@@ -751,7 +751,7 @@ mseintr(arg)
 			sc->sc_flags &= ~MSESC_WANT;
 			wakeup(sc);
 		}
-		selwakeup(&sc->sc_selp);
+		selwakeuppri(&sc->sc_selp, MSEPRI);
 	}
 }
 
diff --git a/sys/i386/isa/spic.c b/sys/i386/isa/spic.c
index a0afcb9..93985e4 100644
--- a/sys/i386/isa/spic.c
+++ b/sys/i386/isa/spic.c
@@ -433,7 +433,7 @@ spictimeout(void *arg)
 			sc->sc_sleeping = 0;
 			wakeup( sc);
 		}
-		selwakeup(&sc->sc_rsel);
+		selwakeuppri(&sc->sc_rsel, PZERO);
 	}
 	spic_call2(sc, 0x81, 0xff); /* Clear event */
 
diff --git a/sys/i386/isa/stallion.c b/sys/i386/isa/stallion.c
index fb5b51f..54d186d 100644
--- a/sys/i386/isa/stallion.c
+++ b/sys/i386/isa/stallion.c
@@ -1234,7 +1234,7 @@ static void stl_start(struct tty *tp)
 			tp->t_state &= ~TS_ASLEEP;
 			wakeup(&tp->t_outq);
 		}
-		selwakeup(&tp->t_wsel);
+		selwakeuppri(&tp->t_wsel, TTOPRI);
 	}
 #endif
 
diff --git a/sys/i4b/driver/i4b_rbch.c b/sys/i4b/driver/i4b_rbch.c
index d89e2c2..40f2c24 100644
--- a/sys/i4b/driver/i4b_rbch.c
+++ b/sys/i4b/driver/i4b_rbch.c
@@ -738,7 +738,7 @@ rbch_rx_data_rdy(int unit)
 	{
 		NDBGL4(L4_RBCHDBG, "unit %d, NO wakeup", unit);
 	}
-	selwakeup(&rbch_softc[unit].selp);
+	selwakeuppri(&rbch_softc[unit].selp, TTIPRI);
 }
 
 /*---------------------------------------------------------------------------*
@@ -759,7 +759,7 @@ rbch_tx_queue_empty(int unit)
 	{
 		NDBGL4(L4_RBCHDBG, "unit %d, NO wakeup", unit);
 	}
-	selwakeup(&rbch_softc[unit].selp);
+	selwakeuppri(&rbch_softc[unit].selp, TTOPRI);
 }
 
 /*---------------------------------------------------------------------------*
@@ -771,7 +771,7 @@ rbch_activity(int unit, int rxtx)
 {
 	if (rbch_softc[unit].sc_cd)
 		rbch_softc[unit].sc_cd->last_active_time = SECOND;
-	selwakeup(&rbch_softc[unit].selp);
+	selwakeuppri(&rbch_softc[unit].selp, TTIPRI);
 }
 
 /*---------------------------------------------------------------------------*
diff --git a/sys/i4b/driver/i4b_tel.c b/sys/i4b/driver/i4b_tel.c
index e13b5f4..c629a44 100644
--- a/sys/i4b/driver/i4b_tel.c
+++ b/sys/i4b/driver/i4b_tel.c
@@ -791,7 +791,7 @@ tel_connect(int unit, void *cdp)
 			sc->devstate &= ~ST_RDWAITDATA;
 			wakeup( &sc->result);
 		}
-		selwakeup(&sc->selp);
+		selwakeuppri(&sc->selp, TTIPRI);
 	}
 }
 
@@ -835,7 +835,7 @@ tel_disconnect(int unit, void *cdp)
 			sc->devstate &= ~ST_RDWAITDATA;
 			wakeup( &sc->result);
 		}
-		selwakeup(&sc->selp);
+		selwakeuppri(&sc->selp, TTIPRI);
 
 		if (sc->devstate & ST_TONE) {
 			sc->devstate &= ~ST_TONE;
@@ -864,7 +864,7 @@ tel_dialresponse(int unit, int status, cause_t cause)
 			sc->devstate &= ~ST_RDWAITDATA;
 			wakeup( &sc->result);
 		}
-		selwakeup(&sc->selp);
+		selwakeuppri(&sc->selp, TTIPRI);
 	}
 }
 	
@@ -891,7 +891,7 @@ tel_rx_data_rdy(int unit)
 		sc->devstate &= ~ST_RDWAITDATA;
 		wakeup( &sc->isdn_linktab->rx_queue);
 	}
-	selwakeup(&sc->selp);
+	selwakeuppri(&sc->selp, TTOPRI);
 }
 
 /*---------------------------------------------------------------------------*
@@ -912,7 +912,7 @@ tel_tx_queue_empty(int unit)
 	if(sc->devstate & ST_TONE) {
 		tel_tone(sc);
 	} else {
-		selwakeup(&sc->selp);
+		selwakeuppri(&sc->selp, TTIPRI);
 	}
 }
 
diff --git a/sys/i4b/layer4/i4b_i4bdrv.c b/sys/i4b/layer4/i4b_i4bdrv.c
index d98fca6..95de760 100644
--- a/sys/i4b/layer4/i4b_i4bdrv.c
+++ b/sys/i4b/layer4/i4b_i4bdrv.c
@@ -820,7 +820,7 @@ i4bputqueue(struct mbuf *m)
 	if(selflag)
 	{
 		selflag = 0;
-		selwakeup(&select_rd_info);
+		selwakeuppri(&select_rd_info, TTIPRI);
 	}
 }
 
@@ -863,6 +863,6 @@ i4bputqueue_hipri(struct mbuf *m)
 	if(selflag)
 	{
 		selflag = 0;
-		selwakeup(&select_rd_info);
+		selwakeuppri(&select_rd_info, TTIPRI);
 	}
 }
diff --git a/sys/isa/psm.c b/sys/isa/psm.c
index ef98da4..2c14bbe 100644
--- a/sys/isa/psm.c
+++ b/sys/isa/psm.c
@@ -2371,7 +2371,7 @@ psmintr(void *arg)
             sc->state &= ~PSM_ASLP;
             wakeup( sc);
     	}
-        selwakeup(&sc->rsel);
+        selwakeuppri(&sc->rsel, PZERO);
     }
 }
 
diff --git a/sys/kern/kern_condvar.c b/sys/kern/kern_condvar.c
index 3344123..d95d9e2 100644
--- a/sys/kern/kern_condvar.c
+++ b/sys/kern/kern_condvar.c
@@ -525,14 +525,21 @@ cv_signal(struct cv *cvp)
  * Should be called with the same mutex as was passed to cv_wait held.
  */
 void
-cv_broadcast(struct cv *cvp)
+cv_broadcastpri(struct cv *cvp, int pri)
 {
+	struct thread	*td;
 
 	KASSERT(cvp != NULL, ("%s: cvp NULL", __func__));
 	mtx_lock_spin(&sched_lock);
 	CV_SIGNAL_VALIDATE(cvp);
-	while (!TAILQ_EMPTY(&cvp->cv_waitq))
+	while (!TAILQ_EMPTY(&cvp->cv_waitq)) {
+		if (pri >= PRI_MIN && pri <= PRI_MAX) {
+			td = TAILQ_FIRST(&cvp->cv_waitq);
+			if (td->td_priority > pri)
+				td->td_priority = pri;
+		}
 		cv_wakeup(cvp);
+	}
 	mtx_unlock_spin(&sched_lock);
 }
 
diff --git a/sys/kern/kern_event.c b/sys/kern/kern_event.c
index 63a914f..a0229a7 100644
--- a/sys/kern/kern_event.c
+++ b/sys/kern/kern_event.c
@@ -925,7 +925,7 @@ kqueue_wakeup(struct kqueue *kq)
 	}
 	if (kq->kq_state & KQ_SEL) {
 		kq->kq_state &= ~KQ_SEL;
-		selwakeup(&kq->kq_sel);
+		selwakeuppri(&kq->kq_sel, PSOCK);
 	}
 	KNOTE(&kq->kq_sel.si_note, 0);
 }
diff --git a/sys/kern/subr_log.c b/sys/kern/subr_log.c
index 031d081..b2ece2d 100644
--- a/sys/kern/subr_log.c
+++ b/sys/kern/subr_log.c
@@ -192,7 +192,7 @@ logtimeout(void *arg)
 		return;
 	}
 	msgbuftrigger = 0;
-	selwakeup(&logsoftc.sc_selp);
+	selwakeuppri(&logsoftc.sc_selp, LOG_RDPRI);
 	if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL)
 		pgsigio(&logsoftc.sc_sigio, SIGIO, 0);
 	if (logsoftc.sc_state & LOG_RDWAIT) {
diff --git a/sys/kern/sys_generic.c b/sys/kern/sys_generic.c
index 221ec00..881be56 100644
--- a/sys/kern/sys_generic.c
+++ b/sys/kern/sys_generic.c
@@ -82,6 +82,7 @@ static int	dofileread(struct thread *, struct file *, int, void *,
 		    size_t, off_t, int);
 static int	dofilewrite(struct thread *, struct file *, int,
 		    const void *, size_t, off_t, int);
+static void	doselwakeup(struct selinfo *, int);
 
 /*
  * Read system call.
@@ -1162,12 +1163,30 @@ selrecord(selector, sip)
 	mtx_unlock(&sellock);
 }
 
+/* Wake up a selecting thread. */
+void
+selwakeup(sip)
+	struct selinfo *sip;
+{
+	doselwakeup(sip, -1);
+}
+
+/* Wake up a selecting thread, and set its priority. */
+void
+selwakeuppri(sip, pri)
+	struct selinfo *sip;
+	int pri;
+{
+	doselwakeup(sip, pri);
+}
+
 /*
  * Do a wakeup when a selectable event occurs.
  */
-void
-selwakeup(sip)
+static void
+doselwakeup(sip, pri)
 	struct selinfo *sip;
+	int pri;
 {
 	struct thread *td;
 
@@ -1176,7 +1195,7 @@ selwakeup(sip)
 	if ((sip->si_flags & SI_COLL) != 0) {
 		nselcoll++;
 		sip->si_flags &= ~SI_COLL;
-		cv_broadcast(&selwait);
+		cv_broadcastpri(&selwait, pri);
 	}
 	if (td == NULL) {
 		mtx_unlock(&sellock);
@@ -1188,6 +1207,8 @@ selwakeup(sip)
 	if (td->td_wchan == &selwait) {
 		cv_waitq_remove(td);
 		TD_CLR_SLEEPING(td);
+		if (pri >= PRI_MIN && pri <= PRI_MAX && td->td_priority > pri)
+			td->td_priority = pri;
 		setrunnable(td);
 	} else
 		td->td_flags &= ~TDF_SELECT;
diff --git a/sys/kern/sys_pipe.c b/sys/kern/sys_pipe.c
index 3208e5c..7b4667b 100644
--- a/sys/kern/sys_pipe.c
+++ b/sys/kern/sys_pipe.c
@@ -447,7 +447,7 @@ pipeselwakeup(cpipe)
 
 	if (cpipe->pipe_state & PIPE_SEL) {
 		cpipe->pipe_state &= ~PIPE_SEL;
-		selwakeup(&cpipe->pipe_sel);
+		selwakeuppri(&cpipe->pipe_sel, PSOCK);
 	}
 	if ((cpipe->pipe_state & PIPE_ASYNC) && cpipe->pipe_sigio)
 		pgsigio(&cpipe->pipe_sigio, SIGIO, 0);
diff --git a/sys/kern/tty.c b/sys/kern/tty.c
index 4bebd65..f34858c 100644
--- a/sys/kern/tty.c
+++ b/sys/kern/tty.c
@@ -2271,7 +2271,7 @@ ttwakeup(struct tty *tp)
 {
 
 	if (SEL_WAITING(&tp->t_rsel))
-		selwakeup(&tp->t_rsel);
+		selwakeuppri(&tp->t_rsel, TTIPRI);
 	if (ISSET(tp->t_state, TS_ASYNC) && tp->t_sigio != NULL)
 		pgsigio(&tp->t_sigio, SIGIO, (tp->t_session != NULL));
 	wakeup(TSA_HUP_OR_INPUT(tp));
@@ -2286,7 +2286,7 @@ ttwwakeup(struct tty *tp)
 {
 
 	if (SEL_WAITING(&tp->t_wsel) && tp->t_outq.c_cc <= tp->t_olowat)
-		selwakeup(&tp->t_wsel);
+		selwakeuppri(&tp->t_wsel, TTOPRI);
 	if (ISSET(tp->t_state, TS_ASYNC) && tp->t_sigio != NULL)
 		pgsigio(&tp->t_sigio, SIGIO, (tp->t_session != NULL));
 	if (ISSET(tp->t_state, TS_BUSY | TS_SO_OCOMPLETE) ==
diff --git a/sys/kern/tty_pty.c b/sys/kern/tty_pty.c
index 2de3a04..874f0ba 100644
--- a/sys/kern/tty_pty.c
+++ b/sys/kern/tty_pty.c
@@ -326,11 +326,11 @@ ptcwakeup(tp, flag)
 	struct pt_ioctl *pti = tp->t_dev->si_drv1;
 
 	if (flag & FREAD) {
-		selwakeup(&pti->pt_selr);
+		selwakeuppri(&pti->pt_selr, TTIPRI);
 		wakeup(TSA_PTC_READ(tp));
 	}
 	if (flag & FWRITE) {
-		selwakeup(&pti->pt_selw);
+		selwakeuppri(&pti->pt_selw, TTOPRI);
 		wakeup(TSA_PTC_WRITE(tp));
 	}
 }
diff --git a/sys/kern/uipc_sockbuf.c b/sys/kern/uipc_sockbuf.c
index d64198d..c4a4c09 100644
--- a/sys/kern/uipc_sockbuf.c
+++ b/sys/kern/uipc_sockbuf.c
@@ -308,7 +308,7 @@ sowakeup(so, sb)
 	register struct sockbuf *sb;
 {
 
-	selwakeup(&sb->sb_sel);
+	selwakeuppri(&sb->sb_sel, PSOCK);
 	sb->sb_flags &= ~SB_SEL;
 	if (sb->sb_flags & SB_WAIT) {
 		sb->sb_flags &= ~SB_WAIT;
diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index 4d4eb63..8e5dec2 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -1744,7 +1744,7 @@ sohasoutofband(so)
 {
 	if (so->so_sigio != NULL)
 		pgsigio(&so->so_sigio, SIGURG, 0);
-	selwakeup(&so->so_rcv.sb_sel);
+	selwakeuppri(&so->so_rcv.sb_sel, PSOCK);
 }
 
 int
diff --git a/sys/kern/uipc_socket2.c b/sys/kern/uipc_socket2.c
index d64198d..c4a4c09 100644
--- a/sys/kern/uipc_socket2.c
+++ b/sys/kern/uipc_socket2.c
@@ -308,7 +308,7 @@ sowakeup(so, sb)
 	register struct sockbuf *sb;
 {
 
-	selwakeup(&sb->sb_sel);
+	selwakeuppri(&sb->sb_sel, PSOCK);
 	sb->sb_flags &= ~SB_SEL;
 	if (sb->sb_flags & SB_WAIT) {
 		sb->sb_flags &= ~SB_WAIT;
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index dc9934b..8a49c13 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -3375,7 +3375,7 @@ vn_pollevent(vp, events)
 		 */
 		vp->v_pollinfo->vpi_events = 0;	/* &= ~events ??? */
 		vp->v_pollinfo->vpi_revents |= events;
-		selwakeup(&vp->v_pollinfo->vpi_selinfo);
+		selwakeuppri(&vp->v_pollinfo->vpi_selinfo, PRIBIO);
 	}
 	mtx_unlock(&vp->v_pollinfo->vpi_lock);
 }
@@ -3394,7 +3394,7 @@ vn_pollgone(vp)
 	VN_KNOTE(vp, NOTE_REVOKE);
 	if (vp->v_pollinfo->vpi_events) {
 		vp->v_pollinfo->vpi_events = 0;
-		selwakeup(&vp->v_pollinfo->vpi_selinfo);
+		selwakeuppri(&vp->v_pollinfo->vpi_selinfo, PRIBIO);
 	}
 	mtx_unlock(&vp->v_pollinfo->vpi_lock);
 }
diff --git a/sys/net/bpf.c b/sys/net/bpf.c
index 1dc40c1..c282dcf 100644
--- a/sys/net/bpf.c
+++ b/sys/net/bpf.c
@@ -528,7 +528,7 @@ bpf_wakeup(d)
 	if (d->bd_async && d->bd_sig && d->bd_sigio)
 		pgsigio(&d->bd_sigio, d->bd_sig, 0);
 
-	selwakeup(&d->bd_sel);
+	selwakeuppri(&d->bd_sel, PRINET);
 	KNOTE(&d->bd_sel.si_note, 0);
 }
 
diff --git a/sys/net/if_tap.c b/sys/net/if_tap.c
index 80d54e6..82ae3b9 100644
--- a/sys/net/if_tap.c
+++ b/sys/net/if_tap.c
@@ -475,7 +475,7 @@ tapclose(dev, foo, bar, td)
 	}
 
 	funsetown(&tp->tap_sigio);
-	selwakeup(&tp->tap_rsel);
+	selwakeuppri(&tp->tap_rsel, PZERO+1);
 
 	tp->tap_flags &= ~TAP_OPEN;
 	tp->tap_pid = 0;
@@ -606,7 +606,7 @@ tapifstart(ifp)
 		if ((tp->tap_flags & TAP_ASYNC) && (tp->tap_sigio != NULL))
 			pgsigio(&tp->tap_sigio, SIGIO, 0);
 
-		selwakeup(&tp->tap_rsel);
+		selwakeuppri(&tp->tap_rsel, PZERO+1);
 		ifp->if_opackets ++; /* obytes are counted in ether_output */
 	}
 
diff --git a/sys/net/if_tun.c b/sys/net/if_tun.c
index b46cef6..e983a5b 100644
--- a/sys/net/if_tun.c
+++ b/sys/net/if_tun.c
@@ -213,7 +213,7 @@ tunstart(struct ifnet *ifp)
 	}
 	if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio)
 		pgsigio(&tp->tun_sigio, SIGIO, 0);
-	selwakeup(&tp->tun_rsel);
+	selwakeuppri(&tp->tun_rsel, PZERO + 1);
 }
 
 static void
@@ -324,7 +324,7 @@ tunclose(dev_t dev, int foo, int bar, struct thread *td)
 	}
 
 	funsetown(&tp->tun_sigio);
-	selwakeup(&tp->tun_rsel);
+	selwakeuppri(&tp->tun_rsel, PZERO + 1);
 
 	TUNDEBUG (ifp, "closed\n");
 	err = rman_release_resource(tp->tun_unit);
diff --git a/sys/pc98/pc98/mse.c b/sys/pc98/pc98/mse.c
index 406d8f3..fe55e7f 100644
--- a/sys/pc98/pc98/mse.c
+++ b/sys/pc98/pc98/mse.c
@@ -810,7 +810,7 @@ mseintr(arg)
 			sc->sc_flags &= ~MSESC_WANT;
 			wakeup(sc);
 		}
-		selwakeup(&sc->sc_selp);
+		selwakeuppri(&sc->sc_selp, MSEPRI);
 	}
 }
 
diff --git a/sys/pccard/mecia.c b/sys/pccard/mecia.c
index 59ef5b1..f3c5b11 100644
--- a/sys/pccard/mecia.c
+++ b/sys/pccard/mecia.c
@@ -499,7 +499,7 @@ mecia_reset(void *chan)
 #endif
 	outb(MECIA_REG1, 0);
 
-	selwakeup(&slt->selp);
+	selwakeuppri(&slt->selp, PZERO);
 }
 
 static void
diff --git a/sys/pccard/pccard.c b/sys/pccard/pccard.c
index 16f3a51..b1ef84a 100644
--- a/sys/pccard/pccard.c
+++ b/sys/pccard/pccard.c
@@ -162,7 +162,7 @@ disable_slot_to(struct slot *slt)
 	else
 		printf("pccard: card deactivated, slot %d\n", slt->slotnum);
 	pccard_remove_beep();
-	selwakeup(&slt->selp);
+	selwakeuppri(&slt->selp, PZERO);
 }
 
 /*
diff --git a/sys/pccard/pcic.c b/sys/pccard/pcic.c
index 8e6677c..10271c9 100644
--- a/sys/pccard/pcic.c
+++ b/sys/pccard/pcic.c
@@ -980,7 +980,7 @@ pcic_reset(void *chan)
 		sp->putb(sp, PCIC_TIME_CMD1, 0xf);
 		sp->putb(sp, PCIC_TIME_RECOV1, 0);
 	}
-	selwakeup(&slt->selp);
+	selwakeuppri(&slt->selp, PZERO);
 }
 
 /*
diff --git a/sys/sys/condvar.h b/sys/sys/condvar.h
index cf6a6c6..6b8b60c 100644
--- a/sys/sys/condvar.h
+++ b/sys/sys/condvar.h
@@ -59,7 +59,9 @@ int	cv_timedwait(struct cv *cvp, struct mtx *mp, int timo);
 int	cv_timedwait_sig(struct cv *cvp, struct mtx *mp, int timo);
 
 void	cv_signal(struct cv *cvp);
-void	cv_broadcast(struct cv *cvp);
+void	cv_broadcastpri(struct cv *cvp, int);
+
+#define cv_broadcast(cvp)	cv_broadcastpri(cvp, -1)
 
 void	cv_waitq_remove(struct thread *td);
 void	cv_abort(struct thread *td);
diff --git a/sys/sys/selinfo.h b/sys/sys/selinfo.h
index 9a03949..ac0db59 100644
--- a/sys/sys/selinfo.h
+++ b/sys/sys/selinfo.h
@@ -58,6 +58,7 @@ struct selinfo {
 void	clear_selinfo_list(struct thread *td);
 void	selrecord(struct thread *selector, struct selinfo *sip);
 void	selwakeup(struct selinfo *sip);
+void	selwakeuppri(struct selinfo *sip, int pri);
 #endif
 
 #endif /* !_SYS_SELINFO_H_ */