diff --git a/sys/ufs/mfs/mfs_vfsops.c b/sys/ufs/mfs/mfs_vfsops.c
index 2bbacd911ab8..9e470f03c4a2 100644
--- a/sys/ufs/mfs/mfs_vfsops.c
+++ b/sys/ufs/mfs/mfs_vfsops.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)mfs_vfsops.c	8.11 (Berkeley) 6/19/95
- * $Id: mfs_vfsops.c,v 1.55 1999/01/21 09:24:46 dillon Exp $
+ * $Id: mfs_vfsops.c,v 1.56 1999/01/28 00:57:54 dillon Exp $
  */
 
 
@@ -396,13 +396,13 @@ mfs_start(mp, flags, p)
 	register int gotsig = 0;
 
 	/*
-	 * Must set P_SYSTEM to prevent system from trying to kill
-	 * this process.  What happens is that the process is unkillable,
-	 * and the swapper loops trying to continuously kill it.  Nor
-	 * can we swap out this process - not unless you want a deadlock,
-	 * anyway.
+	 * We must set P_NOSWAP to prevent the system from trying to swap
+	 * out or kill ( when swap space is low, see vm/pageout.c ) the
+	 * process.  A deadlock can occur if the process is swapped out,
+	 * and the system can loop trying to kill the unkillable ( while
+	 * references exist ) MFS process when swap space is low.
 	 */
-	curproc->p_flag |= P_SYSTEM;
+	curproc->p_flag |= P_NOSWAP;
 
 	while (mfsp->mfs_active) {
 		int s;
diff --git a/sys/vm/vm_pageout.c b/sys/vm/vm_pageout.c
index 5f1b56da617d..8a1ffcce6613 100644
--- a/sys/vm/vm_pageout.c
+++ b/sys/vm/vm_pageout.c
@@ -65,7 +65,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_pageout.c,v 1.136 1999/02/08 00:37:36 dillon Exp $
+ * $Id: vm_pageout.c,v 1.138 1999/02/19 19:14:48 luoqi Exp $
  */
 
 /*
@@ -1144,7 +1144,7 @@ rescan0:
 			/*
 			 * if this is a system process, skip it
 			 */
-			if ((p->p_flag & P_SYSTEM) || (p->p_pid == 1) ||
+			if ((p->p_flag & (P_SYSTEM|P_NOSWAP)) || (p->p_pid == 1) ||
 			    ((p->p_pid < 48) && (vm_swap_size != 0))) {
 				continue;
 			}