document the scheduler types and how to specify them.

some pointers from schwarze@

diff --git a/share/man/man9/bufq_init.9 b/share/man/man9/bufq_init.9
index caec091..cceb877 100644 (file)
--- a/share/man/man9/bufq_init.9
+++ b/share/man/man9/bufq_init.9
@@ -1,4 +1,4 @@
-.\"    $OpenBSD: bufq_init.9,v 1.2 2014/07/24 01:26:33 schwarze Exp $
+.\"    $OpenBSD: bufq_init.9,v 1.3 2014/07/25 01:34:29 dlg Exp $
 .\"
 .\" Copyright (c) 2013 David Gwynne <dlg@openbsd.org>
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: July 24 2014 $
+.Dd $Mdocdate: July 25 2014 $
 .Dt BUFQ_INIT 9
 .Os
 .Sh NAME
@@ -71,6 +71,25 @@ can be used to change the scheduler currently used by
 to the algorithm specified by
 .Fa type .
 .Pp
+The
+.Fa type
+argument to
+.Fn bufq_init
+and
+.Fn bufq_switch
+can be one of the following scheduling algorithms:
+.Pp
+.Bl -tag -offset indent -width BUFQ_DEFAULT -compact
+.It Dv BUFQ_FIFO
+A simple First-In First-Out queue.
+.It Dv BUFQ_NSCAN
+Takes batches of "N" bufs from the queue and sorts them for optimal
+head movement.
+.It Dv BUFQ_DEFAULT
+This currently aliases
+.Dv BUFQ_NSCAN .
+.El
+.Pp
 .Fn bufq_destroy
 frees any state that was used by the scheduler.
 .Pp