--- old/src/hotspot/share/gc/g1/g1FullCollector.cpp	2017-11-06 12:26:49.929778866 +0100
+++ new/src/hotspot/share/gc/g1/g1FullCollector.cpp	2017-11-06 12:26:49.673768708 +0100
@@ -74,7 +74,8 @@
     _preserved_marks_set(true),
     _reference_processor(reference_processor),
     _serial_compaction_point(),
-    _is_alive_mutator(_reference_processor, NULL) {
+    _is_alive(_mark_bitmap),
+    _is_alive_mutator(_reference_processor, &_is_alive) {
   assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
 
   _preserved_marks_set.init(_num_workers);
@@ -153,25 +154,24 @@
   reference_processing.execute(scope()->timer(), scope()->tracer());
 
   // Weak oops cleanup.
-  G1IsAliveClosure is_alive(mark_bitmap());
   {
     GCTraceTime(Debug, gc, phases) trace("Phase 1: Weak Processing", scope()->timer());
-    WeakProcessor::weak_oops_do(&is_alive, &do_nothing_cl);
+    WeakProcessor::weak_oops_do(&_is_alive, &do_nothing_cl);
   }
 
   // Class unloading and cleanup.
   if (ClassUnloading) {
     GCTraceTime(Debug, gc, phases) debug("Phase 1: Class Unloading and Cleanup", scope()->timer());
     // Unload classes and purge the SystemDictionary.
-    bool purged_class = SystemDictionary::do_unloading(&is_alive, scope()->timer());
-    G1CollectedHeap::heap()->complete_cleaning(&is_alive, purged_class);
+    bool purged_class = SystemDictionary::do_unloading(&_is_alive, scope()->timer());
+    G1CollectedHeap::heap()->complete_cleaning(&_is_alive, purged_class);
   } else {
     GCTraceTime(Debug, gc, phases) debug("Phase 1: String and Symbol Tables Cleanup", scope()->timer());
     // If no class unloading just clean out strings and symbols.
-    G1CollectedHeap::heap()->partial_cleaning(&is_alive, true, true, G1StringDedup::is_enabled());
+    G1CollectedHeap::heap()->partial_cleaning(&_is_alive, true, true, G1StringDedup::is_enabled());
   }
 
-  scope()->tracer()->report_object_count_after_gc(&is_alive);
+  scope()->tracer()->report_object_count_after_gc(&_is_alive);
 }
 
 void G1FullCollector::prepare_compaction_common() {
--- old/src/hotspot/share/gc/g1/g1FullCollector.hpp	2017-11-06 12:26:50.245791404 +0100
+++ new/src/hotspot/share/gc/g1/g1FullCollector.hpp	2017-11-06 12:26:50.005781881 +0100
@@ -27,6 +27,7 @@
 
 #include "gc/g1/g1FullGCCompactionPoint.hpp"
 #include "gc/g1/g1FullGCMarker.hpp"
+#include "gc/g1/g1FullGCOopClosures.hpp"
 #include "gc/shared/preservedMarks.hpp"
 #include "gc/shared/referenceProcessor.hpp"
 #include "gc/shared/taskqueue.hpp"
@@ -52,6 +53,7 @@
   ReferenceProcessor*       _reference_processor;
   G1FullGCCompactionPoint   _serial_compaction_point;
 
+  G1IsAliveClosure          _is_alive;
   ReferenceProcessorIsAliveMutator _is_alive_mutator;
 
 public: