--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Thu Feb 07 18:40:45 2013 -0800
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Sun Feb 10 21:15:16 2013 +0100
@@ -1893,7 +1893,6 @@
   _ref_processor_stw(NULL),
   _process_strong_tasks(new SubTasksDone(G1H_PS_NumElements)),
   _bot_shared(NULL),
-  _objs_with_preserved_marks(NULL), _preserved_marks_of_objs(NULL),
   _evac_failure_scan_stack(NULL) ,
   _mark_in_progress(false),
   _cg1r(NULL), _summary_bytes_used(0),
@@ -4215,22 +4214,15 @@
   assert(check_cset_heap_region_claim_values(HeapRegion::InitialClaimValue), "sanity");
 
   // Now restore saved marks, if any.
-  if (_objs_with_preserved_marks != NULL) {
-    assert(_preserved_marks_of_objs != NULL, "Both or none.");
-    guarantee(_objs_with_preserved_marks->length() ==
-              _preserved_marks_of_objs->length(), "Both or none.");
-    for (int i = 0; i < _objs_with_preserved_marks->length(); i++) {
-      oop obj   = _objs_with_preserved_marks->at(i);
-      markOop m = _preserved_marks_of_objs->at(i);
-      obj->set_mark(m);
-    }
-
-    // Delete the preserved marks growable arrays (allocated on the C heap).
-    delete _objs_with_preserved_marks;
-    delete _preserved_marks_of_objs;
-    _objs_with_preserved_marks = NULL;
-    _preserved_marks_of_objs = NULL;
-  }
+  assert(_objs_with_preserved_marks.size() ==
+            _preserved_marks_of_objs.size(), "Both or none.");
+  while (!_objs_with_preserved_marks.is_empty()) {
+    oop obj = _objs_with_preserved_marks.pop();
+    markOop m = _preserved_marks_of_objs.pop();
+    obj->set_mark(m);
+  }
+  _objs_with_preserved_marks.clear(true);
+  _preserved_marks_of_objs.clear(true);
 }
 
 void G1CollectedHeap::push_on_evac_failure_scan_stack(oop obj) {
@@ -4313,15 +4305,8 @@
   // We want to call the "for_promotion_failure" version only in the
   // case of a promotion failure.
   if (m->must_be_preserved_for_promotion_failure(obj)) {
-    if (_objs_with_preserved_marks == NULL) {
-      assert(_preserved_marks_of_objs == NULL, "Both or none.");
-      _objs_with_preserved_marks =
-        new (ResourceObj::C_HEAP, mtGC) GrowableArray<oop>(40, true);
-      _preserved_marks_of_objs =
-        new (ResourceObj::C_HEAP, mtGC) GrowableArray<markOop>(40, true);
-    }
-    _objs_with_preserved_marks->push(obj);
-    _preserved_marks_of_objs->push(m);
+    _objs_with_preserved_marks.push(obj);
+    _preserved_marks_of_objs.push(m);
   }
 }
 

--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Thu Feb 07 18:40:45 2013 -0800
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Sun Feb 10 21:15:16 2013 +0100
@@ -37,6 +37,7 @@
 #include "memory/barrierSet.hpp"
 #include "memory/memRegion.hpp"
 #include "memory/sharedHeap.hpp"
+#include "utilities/stack.hpp"
 
 // A "G1CollectedHeap" is an implementation of a java heap for HotSpot.
 // It uses the "Garbage First" heap organization and algorithm, which
@@ -877,10 +878,9 @@
   // forwarding pointers to themselves.  Reset them.
   void remove_self_forwarding_pointers();
 
-  // When one is non-null, so is the other.  Together, they each pair is
-  // an object with a preserved mark, and its mark value.
-  GrowableArray<oop>*     _objs_with_preserved_marks;
-  GrowableArray<markOop>* _preserved_marks_of_objs;
+  // Together, these store an object with a preserved mark, and its mark value.
+  Stack<oop, mtGC>     _objs_with_preserved_marks;
+  Stack<markOop, mtGC> _preserved_marks_of_objs;
 
   // Preserve the mark of "obj", if necessary, in preparation for its mark
   // word being overwritten with a self-forwarding-pointer.