--- a/hotspot/src/share/vm/gc_implementation/g1/satbQueue.hpp	Mon Mar 22 02:40:53 2010 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/satbQueue.hpp	Thu Mar 18 12:14:59 2010 -0400
@@ -29,8 +29,7 @@
 class ObjPtrQueue: public PtrQueue {
 public:
   ObjPtrQueue(PtrQueueSet* qset_, bool perm = false) :
-    PtrQueue(qset_, perm)
-  {}
+    PtrQueue(qset_, perm, qset_->is_active()) { }
   // Apply the closure to all elements, and reset the index to make the
   // buffer empty.
   void apply_closure(ObjectClosure* cl);
@@ -55,6 +54,9 @@
   // is ignored.
   bool apply_closure_to_completed_buffer_work(bool par, int worker);
 
+#ifdef ASSERT
+  void dump_active_values(JavaThread* first, bool expected_active);
+#endif // ASSERT
 
 public:
   SATBMarkQueueSet();
@@ -65,9 +67,11 @@
 
   static void handle_zero_index_for_thread(JavaThread* t);
 
-  // Apply "set_active(b)" to all thread tloq's.  Should be called only
-  // with the world stopped.
-  void set_active_all_threads(bool b);
+  // Apply "set_active(b)" to all Java threads' SATB queues. It should be
+  // called only with the world stopped. The method will assert that the
+  // SATB queues of all threads it visits, as well as the SATB queue
+  // set itself, has an active value same as expected_active.
+  void set_active_all_threads(bool b, bool expected_active);
 
   // Register "blk" as "the closure" for all queues.  Only one such closure
   // is allowed.  The "apply_closure_to_completed_buffer" method will apply