Add a new kernel sleep function pause(9). pause(9) is for places that

want an equivalent of DELAY(9) that sleeps instead of spins.  It accepts
a wmesg and a timeout and is not interrupted by signals.  It uses a private
wait channel that should never be woken up by wakeup(9) or wakeup_one(9).

Glanced at by:	phk

2 files changed, 24 insertions, 4 deletions

diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index 2298e39b8a04..64c11abf85f9 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -997,6 +997,7 @@ MLINKS+=signal.9 cursig.9 \
 	signal.9 trapsignal.9
 MLINKS+=sleep.9 msleep.9 \
 	sleep.9 msleep_spin.9 \
+	sleep.9 pause.9 \
 	sleep.9 tsleep.9 \
 	sleep.9 wakeup.9 \
 	sleep.9 wakeup_one.9
diff --git a/share/man/man9/sleep.9 b/share/man/man9/sleep.9
index db97565b74d5..0973fc5019ce 100644
--- a/share/man/man9/sleep.9
+++ b/share/man/man9/sleep.9
@@ -31,6 +31,7 @@
 .Sh NAME
 .Nm msleep ,
 .Nm msleep_spin ,
+.Nm pause ,
 .Nm tsleep ,
 .Nm wakeup
 .Nd wait for events
@@ -39,12 +40,14 @@
 .In sys/systm.h
 .In sys/proc.h
 .Ft int
-.Fn tsleep "void *chan" "int priority" "const char *wmesg" "int timo"
-.Ft int
 .Fn msleep "void *chan" "struct mtx *mtx" "int priority" "const char *wmesg" "int timo"
 .Ft int
 .Fn msleep_spin "void *chan" "struct mtx *mtx" "const char *wmesg" "int timo"
 .Ft void
+.Fn pause "const char *wmesg" "int timo"
+.Ft int
+.Fn tsleep "void *chan" "int priority" "const char *wmesg" "int timo"
+.Ft void
 .Fn wakeup "void *chan"
 .Ft void
 .Fn wakeup_one "void *chan"
@@ -53,6 +56,7 @@ The functions
 .Fn tsleep ,
 .Fn msleep ,
 .Fn msleep_spin ,
+.Fn pause ,
 .Fn wakeup ,
 and
 .Fn wakeup_one
@@ -61,12 +65,13 @@ If a thread must wait for an
 external event, it is put to sleep by
 .Fn tsleep ,
 .Fn msleep ,
+.Fn msleep_spin ,
 or
-.Fn msleep_spin .
+.Fn pause .
 The parameter
 .Fa chan
 is an arbitrary address that uniquely identifies the event on which
-the thread is being asleep.
+the thread is being put to sleep.
 All threads sleeping on a single
 .Fa chan
 are woken up later by
@@ -184,6 +189,16 @@ and it does not support the
 and
 .Dv PCATCH
 flags.
+.Pp
+The
+.Fn pause
+function is a wrapper around
+.Fn tsleep
+that suspends execution of the current thread for the indicated timeout.
+The thread can not be awakened early by signals or calls to
+.Fn wakeup
+or
+.Fn wakeup_one.
 .Sh RETURN VALUES
 See above.
 .Sh SEE ALSO
@@ -211,6 +226,10 @@ function appeared in
 and the
 .Fn msleep_spin
 function appeared in
+.Fx 6.2 .
+.The
+.Fn pause
+function appeared in
 .Fx 7.0 .
 .Pp
 The