From c38957d22b79e58dcfc2f1111afcbbc0019cfe89 Mon Sep 17 00:00:00 2001
From: dyson <dyson@FreeBSD.org>
Date: Sat, 9 Aug 1997 10:13:32 +0000
Subject: Modify the scheduling policy to take into account disk I/O waits as
 chargeable CPU usage.  This should mitigate the problem of processes doing
 disk I/O hogging the CPU.  Various users have reported the problem, and test
 code shows that the problem should now be gone.

---
 sys/kern/subr_trap.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

(limited to 'sys/kern/subr_trap.c')

diff --git a/sys/kern/subr_trap.c b/sys/kern/subr_trap.c
index 7110933..516925f 100644
--- a/sys/kern/subr_trap.c
+++ b/sys/kern/subr_trap.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)trap.c	7.4 (Berkeley) 5/13/91
- *	$Id: trap.c,v 1.101 1997/07/20 08:37:23 bde Exp $
+ *	$Id: trap.c,v 1.102 1997/08/09 00:02:52 dyson Exp $
  */
 
 /*
@@ -144,6 +144,19 @@ userret(p, frame, oticks)
 
 	while ((sig = CURSIG(p)) != 0)
 		postsig(sig);
+
+#if !defined(NO_SCHEDULE_MODS)
+	if (!want_resched &&
+		(p->p_priority <= p->p_usrpri) &&
+		(p->p_rtprio.type == RTP_PRIO_NORMAL)) {
+		 int newpriority;
+		 p->p_estcpu += 1;
+		 newpriority = PUSER + p->p_estcpu / 4 + 2 * p->p_nice;
+		 newpriority = min(newpriority, MAXPRI);
+		 p->p_usrpri = newpriority;
+	}
+#endif
+		
 	p->p_priority = p->p_usrpri;
 	if (want_resched) {
 		/*
-- 
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