diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index 13b40b2f6aab..06003c98f517 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -39,7 +39,7 @@
  * SUCH DAMAGE.
  *
  *	from:	@(#)pmap.c	7.7 (Berkeley)	5/12/91
- *	$Id: pmap.c,v 1.29 1994/08/06 10:25:36 davidg Exp $
+ *	$Id: pmap.c,v 1.30 1994/08/07 13:10:19 davidg Exp $
  */
 
 /*
@@ -695,7 +695,6 @@ pmap_alloc_pv_entry()
 			 * let the kernel see it
 			 */
 			pmap_kenter(pvva, VM_PAGE_TO_PHYS(m));
-			tlbflush();
 
 			entry = (pv_entry_t) pvva;
 			/*
@@ -1345,9 +1344,17 @@ pmap_kenter(va, pa)
 	register vm_offset_t pa;
 {
 	register pt_entry_t *pte;
+	int wasvalid = 0;
+
 	pte = vtopte(va);
 
+	if (*pte)
+		wasvalid++;
+
 	*pte = (pt_entry_t) ( (int) (pa | PG_RW | PG_V | PG_W));
+
+	if (wasvalid)
+		tlbflush();
 }
 
 /*
diff --git a/sys/amd64/amd64/vm_machdep.c b/sys/amd64/amd64/vm_machdep.c
index d570b6bd3098..906ea751623d 100644
--- a/sys/amd64/amd64/vm_machdep.c
+++ b/sys/amd64/amd64/vm_machdep.c
@@ -38,7 +38,7 @@
  *
  *	from: @(#)vm_machdep.c	7.3 (Berkeley) 5/13/91
  *	Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
- *	$Id: vm_machdep.c,v 1.24 1994/08/06 10:25:37 davidg Exp $
+ *	$Id: vm_machdep.c,v 1.25 1994/08/07 03:31:52 davidg Exp $
  */
 
 #include "npx.h"
@@ -243,7 +243,6 @@ int count;
 		pa = vm_bounce_page_find(1);
 		pmap_kenter(kva + i * NBPG, pa);
 	}
-	pmap_update();
 	return kva;
 }
 
@@ -356,7 +355,6 @@ vm_bounce_alloc(bp)
 			 * if we are writing, the copy the data into the page
 			 */
 			if ((bp->b_flags & B_READ) == 0) {
-				pmap_update();
 				bcopy((caddr_t) va, (caddr_t) kva + (NBPG * i), NBPG);
 			}
 		} else {
@@ -367,7 +365,6 @@ vm_bounce_alloc(bp)
 		}
 		va += NBPG;
 	}
-	pmap_update();
 
 /*
  * flag the buffer as being bounced
@@ -677,7 +674,6 @@ pagemove(from, to, size)
 		to += PAGE_SIZE;
 		size -= PAGE_SIZE;
 	}
-	pmap_update();
 }
 
 /*
@@ -761,7 +757,6 @@ vmapbuf(bp)
 		addr += PAGE_SIZE;
 		kva += PAGE_SIZE;
 	}
-	pmap_update();
 }
 
 /*
diff --git a/sys/i386/i386/pmap.c b/sys/i386/i386/pmap.c
index 13b40b2f6aab..06003c98f517 100644
--- a/sys/i386/i386/pmap.c
+++ b/sys/i386/i386/pmap.c
@@ -39,7 +39,7 @@
  * SUCH DAMAGE.
  *
  *	from:	@(#)pmap.c	7.7 (Berkeley)	5/12/91
- *	$Id: pmap.c,v 1.29 1994/08/06 10:25:36 davidg Exp $
+ *	$Id: pmap.c,v 1.30 1994/08/07 13:10:19 davidg Exp $
  */
 
 /*
@@ -695,7 +695,6 @@ pmap_alloc_pv_entry()
 			 * let the kernel see it
 			 */
 			pmap_kenter(pvva, VM_PAGE_TO_PHYS(m));
-			tlbflush();
 
 			entry = (pv_entry_t) pvva;
 			/*
@@ -1345,9 +1344,17 @@ pmap_kenter(va, pa)
 	register vm_offset_t pa;
 {
 	register pt_entry_t *pte;
+	int wasvalid = 0;
+
 	pte = vtopte(va);
 
+	if (*pte)
+		wasvalid++;
+
 	*pte = (pt_entry_t) ( (int) (pa | PG_RW | PG_V | PG_W));
+
+	if (wasvalid)
+		tlbflush();
 }
 
 /*
diff --git a/sys/i386/i386/vm_machdep.c b/sys/i386/i386/vm_machdep.c
index d570b6bd3098..906ea751623d 100644
--- a/sys/i386/i386/vm_machdep.c
+++ b/sys/i386/i386/vm_machdep.c
@@ -38,7 +38,7 @@
  *
  *	from: @(#)vm_machdep.c	7.3 (Berkeley) 5/13/91
  *	Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
- *	$Id: vm_machdep.c,v 1.24 1994/08/06 10:25:37 davidg Exp $
+ *	$Id: vm_machdep.c,v 1.25 1994/08/07 03:31:52 davidg Exp $
  */
 
 #include "npx.h"
@@ -243,7 +243,6 @@ int count;
 		pa = vm_bounce_page_find(1);
 		pmap_kenter(kva + i * NBPG, pa);
 	}
-	pmap_update();
 	return kva;
 }
 
@@ -356,7 +355,6 @@ vm_bounce_alloc(bp)
 			 * if we are writing, the copy the data into the page
 			 */
 			if ((bp->b_flags & B_READ) == 0) {
-				pmap_update();
 				bcopy((caddr_t) va, (caddr_t) kva + (NBPG * i), NBPG);
 			}
 		} else {
@@ -367,7 +365,6 @@ vm_bounce_alloc(bp)
 		}
 		va += NBPG;
 	}
-	pmap_update();
 
 /*
  * flag the buffer as being bounced
@@ -677,7 +674,6 @@ pagemove(from, to, size)
 		to += PAGE_SIZE;
 		size -= PAGE_SIZE;
 	}
-	pmap_update();
 }
 
 /*
@@ -761,7 +757,6 @@ vmapbuf(bp)
 		addr += PAGE_SIZE;
 		kva += PAGE_SIZE;
 	}
-	pmap_update();
 }
 
 /*
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index 31f43eec73d4..61a347612e1c 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -16,7 +16,7 @@
  * 4. Modifications may be freely made to this file if the above conditions
  *    are met.
  *
- * $Id: vfs_bio.c,v 1.5 1994/08/04 19:43:13 davidg Exp $
+ * $Id: vfs_bio.c,v 1.6 1994/08/06 09:15:28 davidg Exp $
  */
 
 #include <sys/param.h>
@@ -692,7 +692,6 @@ vm_hold_load_pages(vm_offset_t froma, vm_offset_t toa) {
 		vm_page_wire(p);
 		pmap_kenter( pg, VM_PAGE_TO_PHYS(p));
 	}
-	pmap_update();
 }
 
 void
@@ -707,7 +706,6 @@ vm_hold_free_pages(vm_offset_t froma, vm_offset_t toa) {
 		pmap_kremove( pg);
 		vm_page_free(p);
 	}
-	pmap_update();
 }
 
 void
diff --git a/sys/vm/vm_kern.c b/sys/vm/vm_kern.c
index 202ca631be0c..c64c2df99644 100644
--- a/sys/vm/vm_kern.c
+++ b/sys/vm/vm_kern.c
@@ -61,7 +61,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_kern.c,v 1.4 1994/08/06 09:15:38 davidg Exp $
+ * $Id: vm_kern.c,v 1.5 1994/08/07 13:10:39 davidg Exp $
  */
 
 /*
@@ -373,7 +373,6 @@ kmem_malloc(map, size, canwait)
 		vm_object_unlock(kmem_object);
 		pmap_kenter( addr + i, VM_PAGE_TO_PHYS(m));
 	}
-	pmap_update();
 	vm_map_unlock(map);
 
 	vm_map_simplify(map, addr);
diff --git a/sys/vm/vm_pager.c b/sys/vm/vm_pager.c
index 1d39709a6eb9..47d3c3d0a65a 100644
--- a/sys/vm/vm_pager.c
+++ b/sys/vm/vm_pager.c
@@ -61,7 +61,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_pager.c,v 1.4 1994/08/06 09:15:40 davidg Exp $
+ * $Id: vm_pager.c,v 1.5 1994/08/07 13:10:42 davidg Exp $
  */
 
 /*
@@ -281,7 +281,6 @@ vm_pager_map_page(m)
 
 	kva = kmem_alloc_wait(pager_map, PAGE_SIZE);
 	pmap_kenter(kva, VM_PAGE_TO_PHYS(m));
-	pmap_update();
 	return(kva);
 }