--- a/hotspot/src/share/vm/services/memoryManager.hpp	Thu Jun 10 08:27:35 2010 -0700
+++ b/hotspot/src/share/vm/services/memoryManager.hpp	Fri Jul 30 22:43:50 2010 +0100
@@ -131,6 +131,9 @@
     return _after_gc_usage_array[pool_index];
   }
 
+  MemoryUsage* before_gc_usage_array() { return _before_gc_usage_array; }
+  MemoryUsage* after_gc_usage_array()  { return _after_gc_usage_array; }
+
   void set_index(size_t index)    { _index = index; }
   void set_start_time(jlong time) { _start_time = time; }
   void set_end_time(jlong time)   { _end_time = time; }
@@ -143,7 +146,7 @@
     set_gc_usage(pool_index, usage, false /* after gc */);
   }
 
-  void copy_stat(GCStatInfo* stat);
+  void clear();
 };
 
 class GCMemoryManager : public MemoryManager {
@@ -153,6 +156,8 @@
   elapsedTimer _accumulated_timer;
   elapsedTimer _gc_timer;         // for measuring every GC duration
   GCStatInfo*  _last_gc_stat;
+  Mutex*       _last_gc_lock;
+  GCStatInfo*  _current_gc_stat;
   int          _num_gc_threads;
 public:
   GCMemoryManager();
@@ -166,11 +171,16 @@
   int    num_gc_threads()               { return _num_gc_threads; }
   void   set_num_gc_threads(int count)  { _num_gc_threads = count; }
 
-  void   gc_begin();
-  void   gc_end();
+  void   gc_begin(bool recordGCBeginTime, bool recordPreGCUsage,
+                  bool recordAccumulatedGCTime);
+  void   gc_end(bool recordPostGCUsage, bool recordAccumulatedGCTime,
+                bool recordGCEndTime, bool countCollection);
 
   void        reset_gc_stat()   { _num_collections = 0; _accumulated_timer.reset(); }
-  GCStatInfo* last_gc_stat()    { return _last_gc_stat; }
+
+  // Copy out _last_gc_stat to the given destination, returning
+  // the collection count. Zero signifies no gc has taken place.
+  size_t get_last_gc_stat(GCStatInfo* dest);
 
   virtual MemoryManager::Name kind() = 0;
 };