--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Tue Jul 14 15:40:39 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Wed Jul 15 12:22:59 2009 -0400
@@ -700,6 +700,9 @@
   size_t g1_reserved_obj_bytes() { return _g1_reserved.byte_size(); }
   virtual size_t capacity() const;
   virtual size_t used() const;
+  // This should be called when we're not holding the heap lock. The
+  // result might be a bit inaccurate.
+  size_t used_unlocked() const;
   size_t recalculate_used() const;
 #ifndef PRODUCT
   size_t recalculate_used_regions() const;