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.

3 files changed, 24 insertions, 3 deletions

diff --git a/sys/kern/kern_physio.c b/sys/kern/kern_physio.c
index 42d1d21..bfa7c01 100644
--- a/sys/kern/kern_physio.c
+++ b/sys/kern/kern_physio.c
@@ -16,7 +16,7 @@
  * 4. Modifications may be freely made to this file if the above conditions
  *    are met.
  *
- * $Id$
+ * $Id: kern_physio.c,v 1.19 1997/02/22 09:39:08 peter Exp $
  */
 
 #include <sys/param.h>
@@ -112,7 +112,11 @@ physio(strategy, bp, dev, rw, minp, uio)
 
 			spl = splbio();
 			while ((bp->b_flags & B_DONE) == 0)
+#if defined(NO_SCHEDULE_MODS)
 				tsleep((caddr_t)bp, PRIBIO, "physstr", 0);
+#else
+				tsleep((caddr_t)bp, curproc->p_usrpri, "physstr", 0);
+#endif
 			splx(spl);
 
 			/* release mapping into kernel space */
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) {
 		/*
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index f2477e5..1239dfb9 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -18,7 +18,7 @@
  * 5. Modifications may be freely made to this file if the above conditions
  *    are met.
  *
- * $Id: vfs_bio.c,v 1.120 1997/06/13 08:30:40 bde Exp $
+ * $Id: vfs_bio.c,v 1.121 1997/06/15 17:56:49 dyson Exp $
  */
 
 /*
@@ -1717,7 +1717,11 @@ biowait(register struct buf * bp)
 
 	s = splbio();
 	while ((bp->b_flags & B_DONE) == 0)
+#if defined(NO_SCHEDULE_MODS)
 		tsleep(bp, PRIBIO, "biowait", 0);
+#else
+		tsleep(bp, curproc->p_usrpri, "biowait", 0);
+#endif
 	splx(s);
 	if (bp->b_flags & B_EINTR) {
 		bp->b_flags &= ~B_EINTR;