Index: sys/vm/swap_pager.c
===================================================================
--- sys/vm/swap_pager.c
+++ sys/vm/swap_pager.c
@@ -311,8 +311,7 @@
 	racct_sub_cred(cred, RACCT_SWAP, decr);
 }
 
-#define SWM_FREE	0x02	/* free, period			*/
-#define SWM_POP		0x04	/* pop out			*/
+#define SWM_POP		0x02	/* pop out			*/
 
 static int swap_pager_full = 2;	/* swap space exhaustion (task killing) */
 static int swap_pager_almost_full = 1; /* swap space exhaustion (w/hysteresis)*/
@@ -911,6 +910,7 @@
     vm_pindex_t offset, int destroysource)
 {
 	vm_pindex_t i;
+	daddr_t first_free, num_free;
 
 	VM_OBJECT_ASSERT_WLOCKED(srcobject);
 	VM_OBJECT_ASSERT_WLOCKED(dstobject);
@@ -937,8 +937,10 @@
 	/*
 	 * transfer source to destination.
 	 */
+	first_free = SWAPBLK_NONE;
+	num_free = 0;
 	for (i = 0; i < dstobject->size; ++i) {
-		daddr_t dstaddr;
+		daddr_t dstaddr, srcaddr;
 
 		/*
 		 * Locate (without changing) the swapblk on the destination,
@@ -947,41 +949,40 @@
 		 * source is thrown away.
 		 */
 		dstaddr = swp_pager_meta_ctl(dstobject, i, 0);
+		srcaddr = swp_pager_meta_ctl(srcobject, i + offset, SWM_POP);
 
+		if (srcaddr == SWAPBLK_NONE)
+			continue;
 		if (dstaddr == SWAPBLK_NONE) {
 			/*
 			 * Destination has no swapblk and is not resident,
 			 * copy source.
+			 *
+			 * swp_pager_meta_build() can sleep.
 			 */
-			daddr_t srcaddr;
-
-			srcaddr = swp_pager_meta_ctl(
-			    srcobject,
-			    i + offset,
-			    SWM_POP
-			);
-
-			if (srcaddr != SWAPBLK_NONE) {
-				/*
-				 * swp_pager_meta_build() can sleep.
-				 */
-				vm_object_pip_add(srcobject, 1);
-				VM_OBJECT_WUNLOCK(srcobject);
-				vm_object_pip_add(dstobject, 1);
-				swp_pager_meta_build(dstobject, i, srcaddr);
-				vm_object_pip_wakeup(dstobject);
-				VM_OBJECT_WLOCK(srcobject);
-				vm_object_pip_wakeup(srcobject);
-			}
-		} else {
+			vm_object_pip_add(srcobject, 1);
+			VM_OBJECT_WUNLOCK(srcobject);
+			vm_object_pip_add(dstobject, 1);
+			swp_pager_meta_build(dstobject, i, srcaddr);
+			vm_object_pip_wakeup(dstobject);
+			VM_OBJECT_WLOCK(srcobject);
+			vm_object_pip_wakeup(srcobject);
+		}
+		else {
 			/*
 			 * Destination has valid swapblk or it is represented
 			 * by a resident page.  We destroy the sourceblock.
 			 */
-
-			swp_pager_meta_ctl(srcobject, i + offset, SWM_FREE);
+			if (first_free + num_free == srcaddr)
+				num_free++;
+			else {
+				swp_pager_freeswapspace(first_free, num_free);
+				first_free = srcaddr;
+				num_free = 1;
+			}
 		}
 	}
+	swp_pager_freeswapspace(first_free, num_free);
 
 	/*
 	 * Free left over swap blocks in source.
@@ -1082,8 +1083,11 @@
 static void
 swap_pager_unswapped(vm_page_t m)
 {
+	daddr_t srcaddr;
 
-	swp_pager_meta_ctl(m->object, m->pindex, SWM_FREE);
+	srcaddr = swp_pager_meta_ctl(m->object, m->pindex, SWM_POP);
+	if (srcaddr != SWAPBLK_NONE)
+		swp_pager_freeswapspace(srcaddr, 1);
 }
 
 /*
@@ -2001,19 +2005,17 @@
 /*
  * SWP_PAGER_METACTL() -  misc control of swap and vm_page_t meta data.
  *
- *	This routine is capable of looking up, popping, or freeing
- *	swapblk assignments in the swap meta data or in the vm_page_t.
- *	The routine typically returns the swapblk being looked-up, or popped,
- *	or SWAPBLK_NONE if the block was freed, or SWAPBLK_NONE if the block
- *	was invalid.  This routine will automatically free any invalid
- *	meta-data swapblks.
+ *	This routine is capable of looking up, or popping swapblk
+ *	assignments in the swap meta data or in the vm_page_t.  The
+ *	routine typically returns the swapblk being looked-up, or popped,
+ *	or SWAPBLK_NONE if the block was invalid.  This routine will
+ *	automatically free any invalid meta-data swapblks.
  *
  *	When acting on a busy resident page and paging is in progress, we
  *	have to wait until paging is complete but otherwise can act on the
  *	busy page.
  *
- *	SWM_FREE	remove and free swap block from metadata
- *	SWM_POP		remove from meta data but do not free.. pop it out
+ *	SWM_POP		remove from meta data.. pop it out
  */
 static daddr_t
 swp_pager_meta_ctl(vm_object_t object, vm_pindex_t pindex, int flags)
@@ -2021,7 +2023,7 @@
 	struct swblk *sb;
 	daddr_t r1;
 
-	if ((flags & (SWM_FREE | SWM_POP)) != 0)
+	if ((flags & SWM_POP) != 0)
 		VM_OBJECT_ASSERT_WLOCKED(object);
 	else
 		VM_OBJECT_ASSERT_LOCKED(object);
@@ -2040,7 +2042,7 @@
 	r1 = sb->d[pindex % SWAP_META_PAGES];
 	if (r1 == SWAPBLK_NONE)
 		return (SWAPBLK_NONE);
-	if ((flags & (SWM_FREE | SWM_POP)) != 0) {
+	if ((flags & SWM_POP) != 0) {
 		sb->d[pindex % SWAP_META_PAGES] = SWAPBLK_NONE;
 		if (swp_pager_swblk_empty(sb, 0, SWAP_META_PAGES)) {
 			SWAP_PCTRIE_REMOVE(&object->un_pager.swp.swp_blks,
@@ -2048,10 +2050,6 @@
 			uma_zfree(swblk_zone, sb);
 		}
 	}
-	if ((flags & SWM_FREE) != 0) {
-		swp_pager_freeswapspace(r1, 1);
-		r1 = SWAPBLK_NONE;
-	}
 	return (r1);
 }