--- a/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp	Tue Feb 10 17:41:19 2015 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp	Wed Feb 11 14:47:21 2015 +0100
@@ -308,7 +308,7 @@
 
   inline ParScanThreadState& thread_state(int i);
 
-  void trace_promotion_failed(YoungGCTracer& gc_tracer);
+  void trace_promotion_failed(const YoungGCTracer* gc_tracer);
   void reset(int active_workers, bool promotion_failed);
   void flush();
 
@@ -357,10 +357,10 @@
   return ((ParScanThreadState*)_data)[i];
 }
 
-void ParScanThreadStateSet::trace_promotion_failed(YoungGCTracer& gc_tracer) {
+void ParScanThreadStateSet::trace_promotion_failed(const YoungGCTracer* gc_tracer) {
   for (int i = 0; i < length(); ++i) {
     if (thread_state(i).promotion_failed()) {
-      gc_tracer.report_promotion_failed(thread_state(i).promotion_failed_info());
+      gc_tracer->report_promotion_failed(thread_state(i).promotion_failed_info());
       thread_state(i).promotion_failed_info().reset();
     }
   }
@@ -883,7 +883,7 @@
 
 // A Generation that does parallel young-gen collection.
 
-void ParNewGeneration::handle_promotion_failed(GenCollectedHeap* gch, ParScanThreadStateSet& thread_state_set, ParNewTracer& gc_tracer) {
+void ParNewGeneration::handle_promotion_failed(GenCollectedHeap* gch, ParScanThreadStateSet& thread_state_set) {
   assert(_promo_failure_scan_stack.is_empty(), "post condition");
   _promo_failure_scan_stack.clear(true); // Clear cached segments.
 
@@ -899,10 +899,10 @@
   _next_gen->promotion_failure_occurred();
 
   // Trace promotion failure in the parallel GC threads
-  thread_state_set.trace_promotion_failed(gc_tracer);
+  thread_state_set.trace_promotion_failed(gc_tracer());
   // Single threaded code may have reported promotion failure to the global state
   if (_promotion_failed_info.has_failed()) {
-    gc_tracer.report_promotion_failed(_promotion_failed_info);
+    _gc_tracer.report_promotion_failed(_promotion_failed_info);
   }
   // Reset the PromotionFailureALot counters.
   NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();)
@@ -941,9 +941,8 @@
   }
   assert(to()->is_empty(), "Else not collection_attempt_is_safe");
 
-  ParNewTracer gc_tracer;
-  gc_tracer.report_gc_start(gch->gc_cause(), _gc_timer->gc_start());
-  gch->trace_heap_before_gc(&gc_tracer);
+  _gc_tracer.report_gc_start(gch->gc_cause(), _gc_timer->gc_start());
+  gch->trace_heap_before_gc(gc_tracer());
 
   init_assuming_no_promotion_failure();
 
@@ -952,7 +951,7 @@
     size_policy->minor_collection_begin();
   }
 
-  GCTraceTime t1(GCCauseString("GC", gch->gc_cause()), PrintGC && !PrintGCDetails, true, NULL, gc_tracer.gc_id());
+  GCTraceTime t1(GCCauseString("GC", gch->gc_cause()), PrintGC && !PrintGCDetails, true, NULL, _gc_tracer.gc_id());
   // Capture heap used before collection (for printing).
   size_t gch_prev_used = gch->used();
 
@@ -994,7 +993,7 @@
 
   // Trace and reset failed promotion info.
   if (promotion_failed()) {
-    thread_state_set.trace_promotion_failed(gc_tracer);
+    thread_state_set.trace_promotion_failed(gc_tracer());
   }
 
   // Process (weak) reference objects found during scavenge.
@@ -1015,16 +1014,16 @@
     ParNewRefProcTaskExecutor task_executor(*this, thread_state_set);
     stats = rp->process_discovered_references(&is_alive, &keep_alive,
                                               &evacuate_followers, &task_executor,
-                                              _gc_timer, gc_tracer.gc_id());
+                                              _gc_timer, _gc_tracer.gc_id());
   } else {
     thread_state_set.flush();
     gch->set_par_threads(0);  // 0 ==> non-parallel.
     gch->save_marks();
     stats = rp->process_discovered_references(&is_alive, &keep_alive,
                                               &evacuate_followers, NULL,
-                                              _gc_timer, gc_tracer.gc_id());
+                                              _gc_timer, _gc_tracer.gc_id());
   }
-  gc_tracer.report_gc_reference_stats(stats);
+  _gc_tracer.report_gc_reference_stats(stats);
   if (!promotion_failed()) {
     // Swap the survivor spaces.
     eden()->clear(SpaceDecorator::Mangle);
@@ -1049,7 +1048,7 @@
 
     adjust_desired_tenuring_threshold();
   } else {
-    handle_promotion_failed(gch, thread_state_set, gc_tracer);
+    handle_promotion_failed(gch, thread_state_set);
   }
   // set new iteration safe limit for the survivor spaces
   from()->set_concurrent_iteration_safe_limit(from()->top());
@@ -1088,12 +1087,12 @@
   }
   rp->verify_no_references_recorded();
 
-  gch->trace_heap_after_gc(&gc_tracer);
-  gc_tracer.report_tenuring_threshold(tenuring_threshold());
+  gch->trace_heap_after_gc(gc_tracer());
+  _gc_tracer.report_tenuring_threshold(tenuring_threshold());
 
   _gc_timer->register_gc_end();
 
-  gc_tracer.report_gc_end(_gc_timer->gc_end(), _gc_timer->time_partitions());
+  _gc_tracer.report_gc_end(_gc_timer->gc_end(), _gc_timer->time_partitions());
 }
 
 static int sum;

--- a/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.hpp	Tue Feb 10 17:41:19 2015 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.hpp	Wed Feb 11 14:47:21 2015 +0100
@@ -333,6 +333,9 @@
   // references to live referent.
   DefNewGeneration::IsAliveClosure _is_alive_closure;
 
+  // GC tracer that should be used during collection.
+  ParNewTracer _gc_tracer;
+
   static oop real_forwardee_slow(oop obj);
   static void waste_some_time();
 
@@ -340,7 +343,7 @@
   // word being overwritten with a self-forwarding-pointer.
   void preserve_mark_if_necessary(oop obj, markOop m);
 
-  void handle_promotion_failed(GenCollectedHeap* gch, ParScanThreadStateSet& thread_state_set, ParNewTracer& gc_tracer);
+  void handle_promotion_failed(GenCollectedHeap* gch, ParScanThreadStateSet& thread_state_set);
 
  protected:
 
@@ -411,6 +414,10 @@
     return _plab_stats.desired_plab_sz();
   }
 
+  const ParNewTracer* gc_tracer() const {
+    return &_gc_tracer;
+  }
+
   static oop real_forwardee(oop obj);
 
   DEBUG_ONLY(static bool is_legal_forward_ptr(oop p);)

--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp	Tue Feb 10 17:41:19 2015 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp	Wed Feb 11 14:47:21 2015 +0100
@@ -663,7 +663,7 @@
   }
 }
 
-void ParallelScavengeHeap::trace_heap(GCWhen::Type when, GCTracer* gc_tracer) {
+void ParallelScavengeHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
   const PSHeapSummary& heap_summary = create_ps_heap_summary();
   gc_tracer->report_gc_heap_summary(when, heap_summary);
 

--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.hpp	Tue Feb 10 17:41:19 2015 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.hpp	Wed Feb 11 14:47:21 2015 +0100
@@ -64,7 +64,7 @@
   // The task manager
   static GCTaskManager* _gc_task_manager;
 
-  void trace_heap(GCWhen::Type when, GCTracer* tracer);
+  void trace_heap(GCWhen::Type when, const GCTracer* tracer);
 
  protected:
   static inline size_t total_invocations();

--- a/hotspot/src/share/vm/gc_implementation/shared/gcTrace.cpp	Tue Feb 10 17:41:19 2015 -0500
+++ b/hotspot/src/share/vm/gc_implementation/shared/gcTrace.cpp	Wed Feb 11 14:47:21 2015 +0100
@@ -162,7 +162,7 @@
   _tenuring_threshold = UNSET_TENURING_THRESHOLD;
 }
 
-void YoungGCTracer::report_promotion_failed(const PromotionFailedInfo& pf_info) {
+void YoungGCTracer::report_promotion_failed(const PromotionFailedInfo& pf_info) const {
   assert_set_gc_id();
 
   send_promotion_failed_event(pf_info);

--- a/hotspot/src/share/vm/gc_implementation/shared/gcTrace.hpp	Tue Feb 10 17:41:19 2015 -0500
+++ b/hotspot/src/share/vm/gc_implementation/shared/gcTrace.hpp	Wed Feb 11 14:47:21 2015 +0100
@@ -153,7 +153,7 @@
   virtual void report_gc_end_impl(const Ticks& timestamp, TimePartitions* time_partitions);
 
  public:
-  void report_promotion_failed(const PromotionFailedInfo& pf_info);
+  void report_promotion_failed(const PromotionFailedInfo& pf_info) const;
   void report_tenuring_threshold(const uint tenuring_threshold);
 
   /*

--- a/hotspot/src/share/vm/gc_interface/collectedHeap.cpp	Tue Feb 10 17:41:19 2015 -0500
+++ b/hotspot/src/share/vm/gc_interface/collectedHeap.cpp	Wed Feb 11 14:47:21 2015 +0100
@@ -132,7 +132,7 @@
   assert_locked_or_safepoint(CodeCache_lock);
 }
 
-void CollectedHeap::trace_heap(GCWhen::Type when, GCTracer* gc_tracer) {
+void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
   const GCHeapSummary& heap_summary = create_heap_summary();
   gc_tracer->report_gc_heap_summary(when, heap_summary);
 
@@ -140,11 +140,11 @@
   gc_tracer->report_metaspace_summary(when, metaspace_summary);
 }
 
-void CollectedHeap::trace_heap_before_gc(GCTracer* gc_tracer) {
+void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
   trace_heap(GCWhen::BeforeGC, gc_tracer);
 }
 
-void CollectedHeap::trace_heap_after_gc(GCTracer* gc_tracer) {
+void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
   trace_heap(GCWhen::AfterGC, gc_tracer);
 }
 

--- a/hotspot/src/share/vm/gc_interface/collectedHeap.hpp	Tue Feb 10 17:41:19 2015 -0500
+++ b/hotspot/src/share/vm/gc_interface/collectedHeap.hpp	Wed Feb 11 14:47:21 2015 +0100
@@ -175,7 +175,7 @@
   // Fill with a single object (either an int array or a java.lang.Object).
   static inline void fill_with_object_impl(HeapWord* start, size_t words, bool zap = true);
 
-  virtual void trace_heap(GCWhen::Type when, GCTracer* tracer);
+  virtual void trace_heap(GCWhen::Type when, const GCTracer* tracer);
 
   // Verification functions
   virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size)
@@ -606,8 +606,8 @@
   virtual void register_nmethod(nmethod* nm);
   virtual void unregister_nmethod(nmethod* nm);
 
-  void trace_heap_before_gc(GCTracer* gc_tracer);
-  void trace_heap_after_gc(GCTracer* gc_tracer);
+  void trace_heap_before_gc(const GCTracer* gc_tracer);
+  void trace_heap_after_gc(const GCTracer* gc_tracer);
 
   // Heap verification
   virtual void verify(bool silent, VerifyOption option) = 0;