Index: sys/vm/swap_pager.c
===================================================================
--- sys/vm/swap_pager.c
+++ sys/vm/swap_pager.c
@@ -758,10 +758,12 @@
  *	This routine may not sleep.
  */
 static void
-swp_pager_freeswapspace(daddr_t blk, int npages)
+swp_pager_freeswapspace(daddr_t blk, daddr_t npages)
 {
 	struct swdevt *sp;
 
+	if (npages == 0)
+		return;
 	mtx_lock(&sw_dev_mtx);
 	TAILQ_FOREACH(sp, &swtailq, sw_list) {
 		if (blk >= sp->sw_first && blk < sp->sw_end) {
@@ -1890,29 +1892,37 @@
 swp_pager_meta_free(vm_object_t object, vm_pindex_t pindex, vm_pindex_t count)
 {
 	struct swblk *sb;
-	vm_pindex_t last;
-	int i;
+	daddr_t first_free, num_free;
+	vm_pindex_t plimit;
+	int i, limit;
 	bool empty;
 
 	VM_OBJECT_ASSERT_WLOCKED(object);
 	if (object->type != OBJT_SWAP || count == 0)
 		return;
 
-	last = pindex + count - 1;
+	first_free = SWAPBLK_NONE;
+	num_free = 0;
+	plimit = pindex + count;
 	for (;;) {
 		sb = SWAP_PCTRIE_LOOKUP_GE(&object->un_pager.swp.swp_blks,
 		    rounddown(pindex, SWAP_META_PAGES));
-		if (sb == NULL || sb->p > last)
+		if (sb == NULL || sb->p >= plimit)
 			break;
-		empty = true;
-		for (i = 0; i < SWAP_META_PAGES; i++) {
+		i = imax(0, pindex - sb->p);
+		limit = imin(SWAP_META_PAGES, plimit - sp->p);
+		empty = (i == 0 && limit == SWAP_META_PAGES);
+		for (; i < limit; i++) {
 			if (sb->d[i] == SWAPBLK_NONE)
 				continue;
-			if (pindex <= sb->p + i && sb->p + i <= last) {
-				swp_pager_freeswapspace(sb->d[i], 1);
-				sb->d[i] = SWAPBLK_NONE;
-			} else
-				empty = false;
+			if (first_free + num_free == sb->d[i])
+				num_free++;
+			else {
+				swp_pager_freeswapspace(first_free, num_free);
+				first_free = sb->d[i];
+				num_free = 1;
+			}
+			sb->d[i] = SWAPBLK_NONE;
 		}
 		pindex = sb->p + SWAP_META_PAGES;
 		if (empty) {
@@ -1921,6 +1931,7 @@
 			uma_zfree(swblk_zone, sb);
 		}
 	}
+	swp_pager_freeswapspace(first_free, num_free);
 }
 
 /*
@@ -1933,6 +1944,7 @@
 swp_pager_meta_free_all(vm_object_t object)
 {
 	struct swblk *sb;
+	daddr_t first_free, num_free;
 	vm_pindex_t pindex;
 	int i;
 
@@ -1940,16 +1952,26 @@
 	if (object->type != OBJT_SWAP)
 		return;
 
+	first_free = SWAPBLK_NONE;
+	num_free = 0;
 	for (pindex = 0; (sb = SWAP_PCTRIE_LOOKUP_GE(
 	    &object->un_pager.swp.swp_blks, pindex)) != NULL;) {
 		pindex = sb->p + SWAP_META_PAGES;
 		for (i = 0; i < SWAP_META_PAGES; i++) {
-			if (sb->d[i] != SWAPBLK_NONE)
-				swp_pager_freeswapspace(sb->d[i], 1);
+			if (sb->d[i] == SWAPBLK_NONE)
+				continue;
+			if (first_free + num_free == sb->d[i])
+				num_free++;
+			else {
+				swp_pager_freeswapspace(first_free, num_free);
+				first_free = sb->d[i];
+				num_free = 1;
+			}
 		}
 		SWAP_PCTRIE_REMOVE(&object->un_pager.swp.swp_blks, sb->p);
 		uma_zfree(swblk_zone, sb);
 	}
+	swp_pager_freeswapspace(first_free, num_free);
 }
 
 /*