--- a/src/share/vm/runtime/objectMonitor.cpp	Thu Jul 07 15:40:36 2016 -0400
+++ b/src/share/vm/runtime/objectMonitor.cpp	Thu Jul 07 14:58:17 2016 -0700
@@ -131,8 +131,6 @@
 static int Knob_QMode               = 0;       // EntryList-cxq policy - queue discipline
 static volatile int InitDone        = 0;
 
-#define TrySpin TrySpin_VaryDuration
-
 // -----------------------------------------------------------------------------
 // Theory of operations -- Monitors lists, thread residency, etc:
 //
@@ -1848,13 +1846,8 @@
 // hysteresis control to damp the transition rate between spinning and
 // not spinning.
 
-intptr_t ObjectMonitor::SpinCallbackArgument = 0;
-int (*ObjectMonitor::SpinCallbackFunction)(intptr_t, int) = NULL;
-
 // Spinning: Fixed frequency (100%), vary duration
-
-
-int ObjectMonitor::TrySpin_VaryDuration(Thread * Self) {
+int ObjectMonitor::TrySpin(Thread * Self) {
   // Dumb, brutal spin.  Good for comparative measurements against adaptive spinning.
   int ctr = Knob_FixedSpin;
   if (ctr != 0) {
@@ -1948,11 +1941,6 @@
         goto Abort;           // abrupt spin egress
       }
       if (Knob_UsePause & 1) SpinPause();
-
-      int (*scb)(intptr_t,int) = SpinCallbackFunction;
-      if (hits > 50 && scb != NULL) {
-        int abend = (*scb)(SpinCallbackArgument, 0);
-      }
     }
 
     if (Knob_UsePause & 2) SpinPause();

--- a/src/share/vm/runtime/objectMonitor.hpp	Thu Jul 07 15:40:36 2016 -0400
+++ b/src/share/vm/runtime/objectMonitor.hpp	Thu Jul 07 14:58:17 2016 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -161,9 +161,6 @@
   Thread * volatile _Responsible;
 
   volatile int _Spinner;            // for exit->spinner handoff optimization
-  volatile int _SpinFreq;           // Spin 1-out-of-N attempts: success rate
-  volatile int _SpinClock;
-  volatile intptr_t _SpinState;     // MCS/CLH list of spinners
   volatile int _SpinDuration;
 
   volatile jint  _count;            // reference count to prevent reclamation/deflation
@@ -238,10 +235,6 @@
   static int cxq_offset_in_bytes()         { return offset_of(ObjectMonitor, _cxq); }
   static int succ_offset_in_bytes()        { return offset_of(ObjectMonitor, _succ); }
   static int EntryList_offset_in_bytes()   { return offset_of(ObjectMonitor, _EntryList); }
-  static int FreeNext_offset_in_bytes()    { return offset_of(ObjectMonitor, FreeNext); }
-  static int WaitSet_offset_in_bytes()     { return offset_of(ObjectMonitor, _WaitSet); }
-  static int Responsible_offset_in_bytes() { return offset_of(ObjectMonitor, _Responsible); }
-  static int Spinner_offset_in_bytes()     { return offset_of(ObjectMonitor, _Spinner); }
 
   // ObjectMonitor references can be ORed with markOopDesc::monitor_value
   // as part of the ObjectMonitor tagging mechanism. When we combine an
@@ -257,11 +250,6 @@
   #define OM_OFFSET_NO_MONITOR_VALUE_TAG(f) \
     ((ObjectMonitor::f ## _offset_in_bytes()) - markOopDesc::monitor_value)
 
-  // Eventually we'll make provisions for multiple callbacks, but
-  // now one will suffice.
-  static int (*SpinCallbackFunction)(intptr_t, int);
-  static intptr_t SpinCallbackArgument;
-
   markOop   header() const;
   void      set_header(markOop hdr);
 
@@ -312,8 +300,6 @@
     _cxq           = NULL;
     _WaitSet       = NULL;
     _recursions    = 0;
-    _SpinFreq      = 0;
-    _SpinClock     = 0;
   }
 
  public:
@@ -353,9 +339,7 @@
   void      UnlinkAfterAcquire(Thread * Self, ObjectWaiter * SelfNode);
   int       TryLock(Thread * Self);
   int       NotRunnable(Thread * Self, Thread * Owner);
-  int       TrySpin_Fixed(Thread * Self);
-  int       TrySpin_VaryFrequency(Thread * Self);
-  int       TrySpin_VaryDuration(Thread * Self);
+  int       TrySpin(Thread * Self);
   void      ExitEpilog(Thread * Self, ObjectWaiter * Wakee);
   bool      ExitSuspendEquivalent(JavaThread * Self);
   void      post_monitor_wait_event(EventJavaMonitorWait * event,

--- a/src/share/vm/runtime/synchronizer.hpp	Thu Jul 07 15:40:36 2016 -0400
+++ b/src/share/vm/runtime/synchronizer.hpp	Thu Jul 07 14:58:17 2016 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -144,8 +144,6 @@
   static void verify() PRODUCT_RETURN;
   static int  verify_objmon_isinpool(ObjectMonitor *addr) PRODUCT_RETURN0;
 
-  static void RegisterSpinCallback(int(*)(intptr_t, int), intptr_t);
-
  private:
   enum { _BLOCKSIZE = 128 };
   // global list of blocks of monitors