--- old/src/share/vm/gc/g1/concurrentMark.cpp	2015-09-08 13:23:19.435225836 +0200
+++ new/src/share/vm/gc/g1/concurrentMark.cpp	2015-09-08 13:23:19.327225840 +0200
@@ -41,6 +41,7 @@
 #include "gc/g1/heapRegionRemSet.hpp"
 #include "gc/g1/heapRegionSet.inline.hpp"
 #include "gc/g1/suspendibleThreadSet.hpp"
+#include "gc/shared/gcId.hpp"
 #include "gc/shared/gcTimer.hpp"
 #include "gc/shared/gcTrace.hpp"
 #include "gc/shared/gcTraceTime.hpp"
@@ -520,7 +521,6 @@
   _has_overflown(false),
   _concurrent(false),
   _has_aborted(false),
-  _aborted_gc_id(GCId::undefined()),
   _restart_for_overflow(false),
   _concurrent_marking_in_progress(false),
 
@@ -991,7 +991,7 @@
       force_overflow()->update();
 
       if (G1Log::fine()) {
-        gclog_or_tty->gclog_stamp(concurrent_gc_id());
+        gclog_or_tty->gclog_stamp();
         gclog_or_tty->print_cr("[GC concurrent-mark-reset-for-overflow]");
       }
     }
@@ -1181,7 +1181,7 @@
   // should not attempt to do any further work.
   if (root_regions()->scan_in_progress()) {
     if (G1Log::fine()) {
-      gclog_or_tty->gclog_stamp(concurrent_gc_id());
+      gclog_or_tty->gclog_stamp();
       gclog_or_tty->print_cr("[GC concurrent-root-region-scan-start]");
     }
 
@@ -1195,7 +1195,7 @@
     _parallel_workers->run_task(&task);
 
     if (G1Log::fine()) {
-      gclog_or_tty->gclog_stamp(concurrent_gc_id());
+      gclog_or_tty->gclog_stamp();
       gclog_or_tty->print_cr("[GC concurrent-root-region-scan-end, %1.7lf secs]", os::elapsedTime() - scan_start);
     }
 
@@ -1245,8 +1245,7 @@
 
  public:
   G1CMTraceTime(const char* title, bool doit)
-    : GCTraceTime(title, doit_and_prepend(doit), false, G1CollectedHeap::heap()->gc_timer_cm(),
-        G1CollectedHeap::heap()->concurrent_mark()->concurrent_gc_id()) {
+    : GCTraceTime(title, doit_and_prepend(doit), false, G1CollectedHeap::heap()->gc_timer_cm()) {
   }
 };
 
@@ -2391,8 +2390,7 @@
                                           &g1_keep_alive,
                                           &g1_drain_mark_stack,
                                           executor,
-                                          g1h->gc_timer_cm(),
-                                          concurrent_gc_id());
+                                          g1h->gc_timer_cm());
     g1h->gc_tracer_cm()->report_gc_reference_stats(stats);
 
     // The do_oop work routines of the keep_alive and drain_marking_stack
@@ -2970,7 +2968,6 @@
     // We haven't started a concurrent cycle or we have already aborted it. No need to do anything.
     return;
   }
-
   // Clear all marks in the next bitmap for the next marking cycle. This will allow us to skip the next
   // concurrent bitmap clearing.
   _nextMarkBitMap->clearAll();
@@ -2988,8 +2985,6 @@
   }
   _first_overflow_barrier_sync.abort();
   _second_overflow_barrier_sync.abort();
-  _aborted_gc_id = _g1h->gc_tracer_cm()->gc_id();
-  assert(!_aborted_gc_id.is_undefined(), "ConcurrentMark::abort() executed more than once?");
   _has_aborted = true;
 
   SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set();
@@ -3004,13 +2999,6 @@
   _g1h->register_concurrent_cycle_end();
 }
 
-const GCId& ConcurrentMark::concurrent_gc_id() {
-  if (has_aborted()) {
-    return _aborted_gc_id;
-  }
-  return _g1h->gc_tracer_cm()->gc_id();
-}
-
 static void print_ms_time_info(const char* prefix, const char* name,
                                NumberSeq& ns) {
   gclog_or_tty->print_cr("%s%5d %12s: total time = %8.2f s (avg = %8.2f ms).",