src/share/vm/gc_implementation/g1/g1RootProcessor.cpp

@@ -251,11 +251,12 @@
     }
   }
 
   {
     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::ThreadRoots, worker_i);
-    Threads::possibly_parallel_oops_do(strong_roots, thread_stack_clds, strong_code);
+    bool is_par = _g1h->n_par_threads() > 0;
+    Threads::possibly_parallel_oops_do(is_par, strong_roots, thread_stack_clds, strong_code);
   }
 }
 
 void G1RootProcessor::process_vm_roots(OopClosure* strong_roots,
                                        OopClosure* weak_roots,