Index: sys/conf/options
===================================================================
--- sys/conf/options
+++ sys/conf/options
@@ -629,6 +629,7 @@
 VM_KMEM_SIZE_MAX	opt_vm.h
 VM_NRESERVLEVEL		opt_vm.h
 VM_LEVEL_0_ORDER	opt_vm.h
+VM_PAGEOUT_PAGE_COUNT	opt_vm.h
 MALLOC_MAKE_FAILURES	opt_vm.h
 MALLOC_PROFILE		opt_vm.h
 MALLOC_DEBUG_MAXZONES	opt_vm.h
Index: sys/vm/vm_object.c
===================================================================
--- sys/vm/vm_object.c
+++ sys/vm/vm_object.c
@@ -1115,7 +1115,7 @@
 vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags,
     int flags, boolean_t *allclean, boolean_t *eio)
 {
-	vm_page_t ma[2 * vm_pageout_page_count - 1], tp;
+	vm_page_t ma[2 * VM_PAGEOUT_PAGE_COUNT - 1], tp;
 	int base, count, runlen;
 
 	vm_page_lock_assert(p, MA_NOTOWNED);
@@ -1123,7 +1123,7 @@
 	VM_OBJECT_ASSERT_WLOCKED(object);
 	base = nitems(ma) / 2;
 	ma[base] = p;
-	for (count = 1, tp = p; count < vm_pageout_page_count; count++) {
+	for (count = 1, tp = p; count < VM_PAGEOUT_PAGE_COUNT; count++) {
 		tp = vm_page_next(tp);
 		if (tp == NULL || vm_page_tryxbusy(tp) == 0)
 			break;
@@ -1134,7 +1134,7 @@
 		ma[base + count] = tp;
 	}
 
-	for (tp = p; count < vm_pageout_page_count; count++) {
+	for (tp = p; count < VM_PAGEOUT_PAGE_COUNT; count++) {
 		tp = vm_page_prev(tp);
 		if (tp == NULL || vm_page_tryxbusy(tp) == 0)
 			break;
Index: sys/vm/vm_pageout.h
===================================================================
--- sys/vm/vm_pageout.h
+++ sys/vm/vm_pageout.h
@@ -72,7 +72,14 @@
  */
 
 extern u_long vm_page_max_user_wired;
-extern int vm_pageout_page_count;
+
+/*
+ * The maximum number of adjacent dirty pages from the same VM object that
+ * are written by a single pageout operation
+ */
+#ifndef VM_PAGEOUT_PAGE_COUNT
+#define	VM_PAGEOUT_PAGE_COUNT	32
+#endif
 
 #define	VM_OOM_MEM	1
 #define	VM_OOM_MEM_PF	2
Index: sys/vm/vm_pageout.c
===================================================================
--- sys/vm/vm_pageout.c
+++ sys/vm/vm_pageout.c
@@ -145,7 +145,6 @@
 #define	VM_INACT_SCAN_RATE	10
 
 static int swapdev_enabled;
-int vm_pageout_page_count = 32;
 
 static int vm_panic_on_oom = 0;
 SYSCTL_INT(_vm, OID_AUTO, panic_on_oom,
@@ -348,7 +347,7 @@
 vm_pageout_cluster(vm_page_t m)
 {
 	vm_object_t object;
-	vm_page_t mc[2 * vm_pageout_page_count - 1], p, pb, ps;
+	vm_page_t mc[2 * VM_PAGEOUT_PAGE_COUNT - 1], p, pb, ps;
 	vm_pindex_t pindex;
 	int ib, is, page_base, pageout_count;
 
@@ -377,7 +376,7 @@
 	 * forward scan if room remains.
 	 */
 more:
-	while (ib != 0 && pageout_count < vm_pageout_page_count) {
+	while (ib != 0 && pageout_count < VM_PAGEOUT_PAGE_COUNT) {
 		if (ib > pindex) {
 			ib = 0;
 			break;
@@ -411,10 +410,10 @@
 		 * We are at an alignment boundary.  Stop here, and switch
 		 * directions.  Do not clear ib.
 		 */
-		if ((pindex - (ib - 1)) % vm_pageout_page_count == 0)
+		if ((pindex - (ib - 1)) % VM_PAGEOUT_PAGE_COUNT == 0)
 			break;
 	}
-	while (pageout_count < vm_pageout_page_count && 
+	while (pageout_count < VM_PAGEOUT_PAGE_COUNT &&
 	    pindex + is < object->size) {
 		if ((p = vm_page_next(ps)) == NULL ||
 		    vm_page_tryxbusy(p) == 0)
@@ -442,7 +441,7 @@
 	 * when possible, even past an alignment boundary.  This catches
 	 * boundary conditions.
 	 */
-	if (ib != 0 && pageout_count < vm_pageout_page_count)
+	if (ib != 0 && pageout_count < VM_PAGEOUT_PAGE_COUNT)
 		goto more;
 
 	return (vm_pageout_flush(&mc[page_base], pageout_count,
@@ -2260,7 +2259,7 @@
 	 */
 	vmd->vmd_pageout_free_min = 2 * MAXBSIZE / PAGE_SIZE +
 	    vmd->vmd_interrupt_free_min;
-	vmd->vmd_free_reserved = vm_pageout_page_count +
+	vmd->vmd_free_reserved = VM_PAGEOUT_PAGE_COUNT +
 	    vmd->vmd_pageout_free_min + vmd->vmd_page_count / 768;
 	vmd->vmd_free_min = vmd->vmd_page_count / 200;
 	vmd->vmd_free_severe = vmd->vmd_free_min / 2;