Index: sys/vm/vm_pageout.c
===================================================================
--- sys/vm/vm_pageout.c
+++ sys/vm/vm_pageout.c
@@ -718,7 +718,8 @@
 	struct mtx *mtx;
 	vm_object_t object;
 	vm_page_t m, marker;
-	int act_delta, error, numpagedout, queue, starting_target;
+	vm_page_astate_t new, old;
+	int act_delta, error, numpagedout, queue, refs, starting_target;
 	int vnodes_skipped;
 	bool pageout_ok;
 
@@ -832,40 +833,46 @@
 		if (vm_page_none_valid(m))
 			goto free_page;
 
-		/*
-		 * If the page has been referenced and the object is not dead,
-		 * reactivate or requeue the page depending on whether the
-		 * object is mapped.
-		 *
-		 * Test PGA_REFERENCED after calling pmap_ts_referenced() so
-		 * that a reference from a concurrently destroyed mapping is
-		 * observed here and now.
-		 */
-		if (object->ref_count != 0)
-			act_delta = pmap_ts_referenced(m);
-		else {
-			KASSERT(!pmap_page_is_mapped(m),
-			    ("page %p is mapped", m));
-			act_delta = 0;
-		}
-		if ((m->a.flags & PGA_REFERENCED) != 0) {
-			vm_page_aflag_clear(m, PGA_REFERENCED);
-			act_delta++;
-		}
-		if (act_delta != 0) {
-			if (object->ref_count != 0) {
+		refs = object->ref_count != 0 ? pmap_ts_referenced(m) : 0;
+
+		for (old = vm_page_astate_load(m);;) {
+			/*
+			 * If the page has been dequeued for some reason, leave
+			 * it alone.  Most likely it has been wired via a pmap
+			 * lookup.
+			 */
+			if (old.queue == PQ_NONE ||
+			    (old.flags & PGA_DEQUEUE) != 0) {
 				vm_page_xunbusy(m);
-				VM_CNT_INC(v_reactivated);
-				vm_page_activate(m);
+				goto next_page;
+			}
 
+			new = old;
+			act_delta = refs;
+			if ((old.flags & PGA_REFERENCED) != 0) {
+				new.flags &= ~PGA_REFERENCED;
+				act_delta++;
+			}
+			if (act_delta == 0) {
+				;
+			} else if (object->ref_count != 0) {
 				/*
-				 * Increase the activation count if the page
-				 * was referenced while in the laundry queue.
-				 * This makes it less likely that the page will
-				 * be returned prematurely to the inactive
-				 * queue.
- 				 */
-				m->a.act_count += act_delta + ACT_ADVANCE;
+				 * Increase the activation count if the page was
+				 * referenced while in the inactive queue.  This
+				 * makes it less likely that the page will be
+				 * returned prematurely to the inactive queue.
+				 */
+				new.act_count += ACT_ADVANCE +
+				    act_delta;
+				if (new.act_count > ACT_MAX)
+					new.act_count = ACT_MAX;
+
+				new.flags |= PGA_REQUEUE;
+				new.queue = PQ_ACTIVE;
+				if (!vm_page_pqstate_commit(m, &old, new))
+					continue;
+
+				vm_page_xunbusy(m);
 
 				/*
 				 * If this was a background laundering, count
@@ -877,12 +884,16 @@
 				 */
 				if (!in_shortfall)
 					launder--;
-				continue;
+				VM_CNT_INC(v_reactivated);
+				goto next_page;
 			} else if ((object->flags & OBJ_DEAD) == 0) {
+				new.flags |= PGA_REQUEUE;
+				if (!vm_page_pqstate_commit(m, &old, new))
+					continue;
 				vm_page_xunbusy(m);
-				vm_page_requeue(m);
-				continue;
+				goto next_page;
 			}
+			break;
 		}
 
 		/*
@@ -901,6 +912,18 @@
 			}
 		}
 
+		/*
+		 * Now we are guaranteed that no other threads are manipulating
+		 * the page, check for a last-second reference.
+		 */
+		old = vm_page_astate_load(m);
+		if (old.queue != queue || (old.flags & PGA_ENQUEUED) == 0)
+			goto next_page;
+		if ((old.flags & PGA_QUEUE_OP_MASK) != 0) {
+			vm_page_pqbatch_submit(m, queue);
+			goto next_page;
+		}
+
 		/*
 		 * Clean pages are freed, and dirty pages are paged out unless
 		 * they belong to a dead object.  Requeueing dirty pages from
@@ -921,7 +944,7 @@
 				pageout_ok = true;
 			if (!pageout_ok) {
 				vm_page_xunbusy(m);
-				vm_page_requeue(m);
+				vm_page_launder(m);
 				continue;
 			}
 
@@ -950,6 +973,7 @@
 			object = NULL;
 		} else
 			vm_page_xunbusy(m);
+next_page:;
 	}
 	if (mtx != NULL) {
 		mtx_unlock(mtx);