8212107: VMThread issues and cleanup

src/hotspot/share/jfr/recorder/repository/jfrEmergencyDump.cpp

@@ -454,12 +454,8 @@ static bool prepare_for_emergency_dump(Thread* thread) {
     Heap_lock->unlock();
   }
 
-  if (VMOperationQueue_lock->owned_by_self()) {
-    VMOperationQueue_lock->unlock();
-  }
-
-  if (VMOperationRequest_lock->owned_by_self()) {
-    VMOperationRequest_lock->unlock();
+  if (VMOperation_lock->owned_by_self()) {
+    VMOperation_lock->unlock();
   }
 
   if (Service_lock->owned_by_self()) {

src/hotspot/share/runtime/mutexLocker.cpp

@@ -65,8 +65,7 @@ Monitor* CodeSweeper_lock             = NULL;
 Mutex*   MethodData_lock              = NULL;
 Mutex*   TouchedMethodLog_lock        = NULL;
 Mutex*   RetData_lock                 = NULL;
-Monitor* VMOperationQueue_lock        = NULL;
-Monitor* VMOperationRequest_lock      = NULL;
+Monitor* VMOperation_lock             = NULL;
 Monitor* Threads_lock                 = NULL;
 Mutex*   NonJavaThreadsList_lock      = NULL;
 Mutex*   NonJavaThreadsListSync_lock  = NULL;
@@ -280,8 +279,7 @@ void mutex_init() {
   def(NonJavaThreadsList_lock      , PaddedMutex,   barrier,     true,  _safepoint_check_never);
   def(NonJavaThreadsListSync_lock  , PaddedMutex,   leaf,        true,  _safepoint_check_never);
 
-  def(VMOperationQueue_lock        , PaddedMonitor, nonleaf,     true,  _safepoint_check_never);  // VM_thread allowed to block on these
-  def(VMOperationRequest_lock      , PaddedMonitor, nonleaf,     true,  _safepoint_check_always);
+  def(VMOperation_lock             , PaddedMonitor, nonleaf,     true,  _safepoint_check_always);  // VM_thread allowed to block on these
   def(RetData_lock                 , PaddedMutex  , nonleaf,     false, _safepoint_check_always);
   def(Terminator_lock              , PaddedMonitor, nonleaf,     true,  _safepoint_check_always);
   def(InitCompleted_lock           , PaddedMonitor, leaf,        true,  _safepoint_check_never);

src/hotspot/share/runtime/mutexLocker.hpp

@@ -58,8 +58,7 @@ extern Monitor* CodeSweeper_lock;                // a lock used by the sweeper o
 extern Mutex*   MethodData_lock;                 // a lock on installation of method data
 extern Mutex*   TouchedMethodLog_lock;           // a lock on allocation of LogExecutedMethods info
 extern Mutex*   RetData_lock;                    // a lock on installation of RetData inside method data
-extern Monitor* VMOperationQueue_lock;           // a lock on queue of vm_operations waiting to execute
-extern Monitor* VMOperationRequest_lock;         // a lock on Threads waiting for a vm_operation to terminate
+extern Monitor* VMOperation_lock;                // a lock on queue of vm_operations waiting to execute
 extern Monitor* Threads_lock;                    // a lock on the Threads table of active Java threads
                                                  // (also used by Safepoints too to block threads creation/destruction)
 extern Mutex*   NonJavaThreadsList_lock;         // a lock on the NonJavaThreads list

src/hotspot/share/runtime/thread.cpp

@@ -255,8 +255,6 @@ Thread::Thread() {
   NOT_PRODUCT(_skip_gcalot = false;)
   _jvmti_env_iteration_count = 0;
   set_allocated_bytes(0);
-  _vm_operation_started_count = 0;
-  _vm_operation_completed_count = 0;
   _current_pending_monitor = NULL;
   _current_pending_monitor_is_from_java = true;
   _current_waiting_monitor = NULL;

src/hotspot/share/runtime/thread.hpp

@@ -401,9 +401,6 @@ class Thread: public ThreadShadow {
 
   JFR_ONLY(DEFINE_THREAD_LOCAL_FIELD_JFR;)      // Thread-local data for jfr
 
-  int   _vm_operation_started_count;            // VM_Operation support
-  int   _vm_operation_completed_count;          // VM_Operation support
-
   ObjectMonitor* _current_pending_monitor;      // ObjectMonitor this thread
                                                 // is waiting to lock
   bool _current_pending_monitor_is_from_java;   // locking is from Java code
@@ -621,11 +618,6 @@ class Thread: public ThreadShadow {
 
   bool is_trace_suspend()               { return (_suspend_flags & _trace_flag) != 0; }
 
-  // VM operation support
-  int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
-  int vm_operation_completed_count()             { return _vm_operation_completed_count; }
-  void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
-
   // For tracking the heavyweight monitor the thread is pending on.
   ObjectMonitor* current_pending_monitor() {
     return _current_pending_monitor;

src/hotspot/share/runtime/vmOperations.hpp

@@ -121,14 +121,12 @@ class VM_Operation : public StackObj {
 
  private:
   Thread*         _calling_thread;
-  VM_Operation*   _next;
-  VM_Operation*   _prev;
 
   // The VM operation name array
   static const char* _names[];
 
  public:
-  VM_Operation() : _calling_thread(NULL), _next(NULL), _prev(NULL) {}
+  VM_Operation() : _calling_thread(NULL) {}
 
   // VM operation support (used by VM thread)
   Thread* calling_thread() const                 { return _calling_thread; }
@@ -148,12 +146,6 @@ class VM_Operation : public StackObj {
   virtual bool doit_prologue()                   { return true; };
   virtual void doit_epilogue()                   {};
 
-  // Linking
-  VM_Operation *next() const                     { return _next; }
-  VM_Operation *prev() const                     { return _prev; }
-  void set_next(VM_Operation *next)              { _next = next; }
-  void set_prev(VM_Operation *prev)              { _prev = prev; }
-
   // Configuration. Override these appropriately in subclasses.
   virtual VMOp_Type type() const = 0;
   virtual bool allow_nested_vm_operations() const { return false; }