svn commit: r198223 - in head/sys: kern sys

[Ed Schouten]

Author: ed
Date: Mon Oct 19 07:17:37 2009
New Revision: 198223
URL: http://svn.freebsd.org/changeset/base/198223

Log:
  Properly set the low watermarks when reducing the baud rate.
  
  Now that buffers are deallocated lazily, we should not use
  tty*q_getsize() to obtain the buffer size to calculate the low
  watermarks. Doing this may cause the watermark to be placed outside the
  typical buffer size.
  
  This caused some regressions after my previous commit to the TTY code,
  which allows pseudo-devices to resize the buffers as well.
  
  Reported by:	yongari, dougb
  MFC after:	1 week

Modified:
  head/sys/kern/tty.c
  head/sys/sys/ttyqueue.h

Modified: head/sys/kern/tty.c
==============================================================================
--- head/sys/kern/tty.c	Sun Oct 18 23:38:59 2009	(r198222)
+++ head/sys/kern/tty.c	Mon Oct 19 07:17:37 2009	(r198223)
@@ -109,14 +109,14 @@ tty_watermarks(struct tty *tp)
 	ttyinq_setsize(&tp->t_inq, tp, bs);
 
 	/* Set low watermark at 10% (when 90% is available). */
-	tp->t_inlow = (ttyinq_getsize(&tp->t_inq) * 9) / 10;
+	tp->t_inlow = (ttyinq_getallocatedsize(&tp->t_inq) * 9) / 10;
 
 	/* Provide an ouput buffer for 0.2 seconds of data. */
 	bs = MIN(tp->t_termios.c_ospeed / 5, TTYBUF_MAX);
 	ttyoutq_setsize(&tp->t_outq, tp, bs);
 
 	/* Set low watermark at 10% (when 90% is available). */
-	tp->t_outlow = (ttyoutq_getsize(&tp->t_outq) * 9) / 10;
+	tp->t_outlow = (ttyoutq_getallocatedsize(&tp->t_outq) * 9) / 10;
 }
 
 static int

Modified: head/sys/sys/ttyqueue.h
==============================================================================
--- head/sys/sys/ttyqueue.h	Sun Oct 18 23:38:59 2009	(r198222)
+++ head/sys/sys/ttyqueue.h	Mon Oct 19 07:17:37 2009	(r198223)
@@ -93,6 +93,13 @@ ttyinq_getsize(struct ttyinq *ti)
 }
 
 static __inline size_t
+ttyinq_getallocatedsize(struct ttyinq *ti)
+{
+
+	return (ti->ti_quota * TTYINQ_DATASIZE);
+}
+
+static __inline size_t
 ttyinq_bytesleft(struct ttyinq *ti)
 {
 	size_t len;
@@ -143,6 +150,13 @@ ttyoutq_getsize(struct ttyoutq *to)
 }
 
 static __inline size_t
+ttyoutq_getallocatedsize(struct ttyoutq *to)
+{
+
+	return (to->to_quota * TTYOUTQ_DATASIZE);
+}
+
+static __inline size_t
 ttyoutq_bytesleft(struct ttyoutq *to)
 {
 	size_t len;