--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp	Fri Sep 18 09:57:47 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp	Wed Sep 23 23:56:15 2009 -0700
@@ -482,6 +482,9 @@
 
   int size = SystemDictionary::number_of_classes() * 2;
   _revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true);
+  // (#klass/k)^2, for k ~ 10 appears a better setting, but this will have to do for
+  // now until we investigate a more optimal setting.
+  _revisit_mdo_stack   = new (ResourceObj::C_HEAP) GrowableArray<DataLayout*>(size*2, true);
 }
 
 
@@ -495,6 +498,7 @@
 
   delete _marking_stack;
   delete _revisit_klass_stack;
+  delete _revisit_mdo_stack;
 }
 
 void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) {
@@ -546,6 +550,10 @@
   follow_weak_klass_links();
   assert(_marking_stack->is_empty(), "just drained");
 
+  // Visit memoized mdo's and clear unmarked weak refs
+  follow_mdo_weak_refs();
+  assert(_marking_stack->is_empty(), "just drained");
+
   // Visit symbol and interned string tables and delete unmarked oops
   SymbolTable::unlink(is_alive_closure());
   StringTable::unlink(is_alive_closure());