--- old/src/hotspot/share/gc/shared/barrierSet.cpp	2018-12-09 03:18:57.010567139 -0500
+++ new/src/hotspot/share/gc/shared/barrierSet.cpp	2018-12-09 03:18:56.598545320 -0500
@@ -26,47 +26,24 @@
 #include "gc/shared/barrierSet.hpp"
 #include "gc/shared/barrierSetAssembler.hpp"
 #include "runtime/thread.hpp"
+#include "utilities/debug.hpp"
 #include "utilities/macros.hpp"
 
 BarrierSet* BarrierSet::_barrier_set = NULL;
 
-class SetBarrierSetNonJavaThread : public ThreadClosure {
-  BarrierSet* _barrier_set;
-  size_t _count;
-
-public:
-  SetBarrierSetNonJavaThread(BarrierSet* barrier_set) :
-    _barrier_set(barrier_set), _count(0) {}
-
-  virtual void do_thread(Thread* thread) {
-    _barrier_set->on_thread_create(thread);
-    ++_count;
-  }
-
-  size_t count() const { return _count; }
-};
-
 void BarrierSet::set_barrier_set(BarrierSet* barrier_set) {
   assert(_barrier_set == NULL, "Already initialized");
   _barrier_set = barrier_set;
 
-  // Some threads are created before the barrier set, so the call to
-  // BarrierSet::on_thread_create had to be deferred for them.  Now that
-  // we have the barrier set, do those deferred calls.
-
-  // First do any non-JavaThreads.
-  SetBarrierSetNonJavaThread njt_closure(_barrier_set);
-  Threads::non_java_threads_do(&njt_closure);
-
-  // Do the current (main) thread.  Ensure it's the one and only
-  // JavaThread so far.  Also verify that it isn't yet on the thread
+  // Notify barrier set of the current (main) thread.  Normally the
+  // Thread constructor deals with this, but the main thread is
+  // created before we get here.  Verify it isn't yet on the thread
   // list, else we'd also need to call BarrierSet::on_thread_attach.
+  // This is the only thread that can exist at this point; the Thread
+  // constructor objects to other threads being created before the
+  // barrier set is available.
   assert(Thread::current()->is_Java_thread(),
          "Expected main thread to be a JavaThread");
-  assert((njt_closure.count() + 1) == Threads::threads_before_barrier_set(),
-         "Unexpected JavaThreads before barrier set initialization: "
-         "Non-JavaThreads: " SIZE_FORMAT ", all: " SIZE_FORMAT,
-         njt_closure.count(), Threads::threads_before_barrier_set());
   assert(!JavaThread::current()->on_thread_list(),
          "Main thread already on thread list.");
   _barrier_set->on_thread_create(Thread::current());