/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 *

 */

class OopClosure;

class ThreadDumpResult;

class ThreadStackTrace;

class ThreadSnapshot;

class StackFrameInfo;

class ThreadConcurrentLocks;

class DeadlockCycle;

// VM monitoring and management support for the thread and

// synchronization subsystem

//

// Thread contention monitoring is disabled by default.

// When enabled, the VM will begin measuring the accumulated

// elapsed time a thread blocked on synchronization.

//

class ThreadService : public AllStatic {

private:

  // These counters could be moved to Threads class

  static PerfCounter*  _total_threads_count;

  static PerfVariable* _live_threads_count;

  static PerfVariable* _peak_threads_count;

  static PerfVariable* _daemon_threads_count;

  // These 2 counters are atomically incremented once the thread is exiting.

  // They will be atomically decremented when ThreadService::remove_thread is called.

  static volatile int  _exiting_threads_count;

  static volatile int  _exiting_daemon_threads_count;

  static bool          _thread_monitoring_contention_enabled;

  static bool          _thread_cpu_time_enabled;

  // Need to keep the list of thread dump result that

  // keep references to methodOop since thread dump can be

  // requested by multiple threads concurrently.

  static ThreadDumpResult* _threaddump_list;

public:

  static void init();

  static void add_thread(JavaThread* thread, bool daemon);

  static void remove_thread(JavaThread* thread, bool daemon);

  static void current_thread_exiting(JavaThread* jt);

  static bool set_thread_monitoring_contention(bool flag);

  static bool is_thread_monitoring_contention() { return _thread_monitoring_contention_enabled; }

  static bool set_thread_cpu_time_enabled(bool flag);

  static bool is_thread_cpu_time_enabled()    { return _thread_cpu_time_enabled; }

  static jlong get_total_thread_count()       { return _total_threads_count->get_value(); }

  static jlong get_peak_thread_count()        { return _peak_threads_count->get_value(); }

  static jlong get_live_thread_count()        { return _live_threads_count->get_value() - _exiting_threads_count; }

  static jlong get_daemon_thread_count()      { return _daemon_threads_count->get_value() - _exiting_daemon_threads_count; }

  static int   exiting_threads_count()        { return _exiting_threads_count; }

  static int   exiting_daemon_threads_count() { return _exiting_daemon_threads_count; }

  // Support for thread dump

  static void   add_thread_dump(ThreadDumpResult* dump);

  static void   remove_thread_dump(ThreadDumpResult* dump);

  static Handle get_current_contended_monitor(JavaThread* thread);

  // This function is called by JVM_DumpThreads.

  static Handle dump_stack_traces(GrowableArray<instanceHandle>* threads,

                                  int num_threads, TRAPS);

  static void   reset_peak_thread_count();

  static void   reset_contention_count_stat(JavaThread* thread);

  static void   reset_contention_time_stat(JavaThread* thread);

  static DeadlockCycle*       find_deadlocks_at_safepoint(bool object_monitors_only);

  // GC support

  static void   oops_do(OopClosure* f);

};

// Per-thread Statistics for synchronization

class ThreadStatistics : public CHeapObj {

private:

  // The following contention statistics are only updated by

  // the thread owning these statistics when contention occurs.

  jlong        _contended_enter_count;

  elapsedTimer _contended_enter_timer;

  jlong        _monitor_wait_count;

  elapsedTimer _monitor_wait_timer;

  jlong        _sleep_count;

  elapsedTimer _sleep_timer;

  // These two reset flags are set to true when another thread

  // requests to reset the statistics.  The actual statistics

  // are reset when the thread contention occurs and attempts

  // to update the statistics.

  bool         _count_pending_reset;

  bool         _timer_pending_reset;

  // Keep accurate times for potentially recursive class operations

  int           _perf_recursion_counts[6];

  elapsedTimer  _perf_timers[6];

  // utility functions

  void  check_and_reset_count()            {

                                             if (!_count_pending_reset) return;

                                             _contended_enter_count = 0;

                                             _monitor_wait_count = 0;

                                             _sleep_count = 0;

                                             _count_pending_reset = 0;

                                           }

  void  check_and_reset_timer()            {

                                             if (!_timer_pending_reset) return;

                                             _contended_enter_timer.reset();

                                             _monitor_wait_timer.reset();

                                             _sleep_timer.reset();

                                             _timer_pending_reset = 0;

                                           }

public:

  ThreadStatistics();

  jlong contended_enter_count()            { return (_count_pending_reset ? 0 : _contended_enter_count); }

  jlong contended_enter_ticks()            { return (_timer_pending_reset ? 0 : _contended_enter_timer.active_ticks()); }

  jlong monitor_wait_count()               { return (_count_pending_reset ? 0 : _monitor_wait_count); }

  jlong monitor_wait_ticks()               { return (_timer_pending_reset ? 0 : _monitor_wait_timer.active_ticks()); }

  jlong sleep_count()                      { return (_count_pending_reset ? 0 : _sleep_count); }

  jlong sleep_ticks()                      { return (_timer_pending_reset ? 0 : _sleep_timer.active_ticks()); }

  void monitor_wait()                      { check_and_reset_count(); _monitor_wait_count++; }

  void monitor_wait_begin()                { check_and_reset_timer(); _monitor_wait_timer.start(); }

  void monitor_wait_end()                  { _monitor_wait_timer.stop(); check_and_reset_timer(); }

  void thread_sleep()                      { check_and_reset_count(); _sleep_count++; }

  void thread_sleep_begin()                { check_and_reset_timer(); _sleep_timer.start(); }

  void thread_sleep_end()                  { _sleep_timer.stop(); check_and_reset_timer(); }

  void contended_enter()                   { check_and_reset_count(); _contended_enter_count++; }

  void contended_enter_begin()             { check_and_reset_timer(); _contended_enter_timer.start(); }

  void contended_enter_end()               { _contended_enter_timer.stop(); check_and_reset_timer(); }

  void reset_count_stat()                  { _count_pending_reset = true; }

  void reset_time_stat()                   { _timer_pending_reset = true; }

  int* perf_recursion_counts_addr()        { return _perf_recursion_counts; }

  elapsedTimer* perf_timers_addr()         { return _perf_timers; }

};

// Thread snapshot to represent the thread state and statistics

class ThreadSnapshot : public CHeapObj {

private:

  JavaThread* _thread;

  oop         _threadObj;

  java_lang_Thread::ThreadStatus _thread_status;

  bool    _is_ext_suspended;

  bool    _is_in_native;

  jlong   _contended_enter_ticks;

  jlong   _contended_enter_count;

  jlong   _monitor_wait_ticks;

  jlong   _monitor_wait_count;

  jlong   _sleep_ticks;

  jlong   _sleep_count;

  oop     _blocker_object;

  oop     _blocker_object_owner;

  ThreadStackTrace*      _stack_trace;

  ThreadConcurrentLocks* _concurrent_locks;

  ThreadSnapshot*        _next;

public:

  // Dummy snapshot

  ThreadSnapshot() : _thread(NULL), _threadObj(NULL), _stack_trace(NULL), _concurrent_locks(NULL), _next(NULL),

                     _blocker_object(NULL), _blocker_object_owner(NULL) {};

  ThreadSnapshot(JavaThread* thread);

  ~ThreadSnapshot();

  java_lang_Thread::ThreadStatus thread_status() { return _thread_status; }

  oop         threadObj() const           { return _threadObj; }

  void        set_next(ThreadSnapshot* n) { _next = n; }

  bool        is_ext_suspended()          { return _is_ext_suspended; }

  bool        is_in_native()              { return _is_in_native; }

  jlong       contended_enter_count()     { return _contended_enter_count; }

  jlong       contended_enter_ticks()     { return _contended_enter_ticks; }

  jlong       monitor_wait_count()        { return _monitor_wait_count; }

  jlong       monitor_wait_ticks()        { return _monitor_wait_ticks; }

  jlong       sleep_count()               { return _sleep_count; }

  jlong       sleep_ticks()               { return _sleep_ticks; }

  oop         blocker_object()            { return _blocker_object; }

  oop         blocker_object_owner()      { return _blocker_object_owner; }

  ThreadSnapshot*   next() const          { return _next; }

  ThreadStackTrace* get_stack_trace()     { return _stack_trace; }

  ThreadConcurrentLocks* get_concurrent_locks()     { return _concurrent_locks; }

  void        dump_stack_at_safepoint(int max_depth, bool with_locked_monitors);

  void        set_concurrent_locks(ThreadConcurrentLocks* l) { _concurrent_locks = l; }

  void        oops_do(OopClosure* f);

};

class ThreadStackTrace : public CHeapObj {

 private:

  JavaThread*                     _thread;

  int                             _depth;  // number of stack frames added

  bool                            _with_locked_monitors;

  GrowableArray<StackFrameInfo*>* _frames;

  GrowableArray<oop>*             _jni_locked_monitors;

 public:

  ThreadStackTrace(JavaThread* thread, bool with_locked_monitors);

  ~ThreadStackTrace();

  JavaThread*     thread()              { return _thread; }

  StackFrameInfo* stack_frame_at(int i) { return _frames->at(i); }

  int             get_stack_depth()     { return _depth; }

  void            add_stack_frame(javaVFrame* jvf);

  void            dump_stack_at_safepoint(int max_depth);

  Handle          allocate_fill_stack_trace_element_array(TRAPS);

  void            oops_do(OopClosure* f);

  GrowableArray<oop>* jni_locked_monitors() { return _jni_locked_monitors; }

  int             num_jni_locked_monitors() { return (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0); }

  bool            is_owned_monitor_on_stack(oop object);

  void            add_jni_locked_monitor(oop object) { _jni_locked_monitors->append(object); }

};

// StackFrameInfo for keeping methodOop and bci during

// stack walking for later construction of StackTraceElement[]

// Java instances

class StackFrameInfo : public CHeapObj {

 private:

  methodOop           _method;

  int                 _bci;

  GrowableArray<oop>* _locked_monitors; // list of object monitors locked by this frame

 public:

  StackFrameInfo(javaVFrame* jvf, bool with_locked_monitors);

  ~StackFrameInfo() {

    if (_locked_monitors != NULL) {

      delete _locked_monitors;

    }

  };

  methodOop method() const       { return _method; }

  int       bci()    const       { return _bci; }

  void      oops_do(OopClosure* f);

  int       num_locked_monitors()       { return (_locked_monitors != NULL ? _locked_monitors->length() : 0); }

  GrowableArray<oop>* locked_monitors() { return _locked_monitors; }

  void      print_on(outputStream* st) const;

};

class ThreadConcurrentLocks : public CHeapObj {

private:

  GrowableArray<instanceOop>* _owned_locks;

  ThreadConcurrentLocks*      _next;

  JavaThread*                 _thread;

 public:

  ThreadConcurrentLocks(JavaThread* thread);

  ~ThreadConcurrentLocks();

  void                        add_lock(instanceOop o);

  void                        set_next(ThreadConcurrentLocks* n) { _next = n; }

  ThreadConcurrentLocks*      next() { return _next; }

  JavaThread*                 java_thread()                      { return _thread; }

  GrowableArray<instanceOop>* owned_locks()                      { return _owned_locks; }

  void                        oops_do(OopClosure* f);

};

class ConcurrentLocksDump : public StackObj {

 private:

  ThreadConcurrentLocks* _map;

  ThreadConcurrentLocks* _last;   // Last ThreadConcurrentLocks in the map

  bool                   _retain_map_on_free;

  void build_map(GrowableArray<oop>* aos_objects);

  void add_lock(JavaThread* thread, instanceOop o);

 public:

  ConcurrentLocksDump(bool retain_map_on_free) : _map(NULL), _last(NULL), _retain_map_on_free(retain_map_on_free) {};

  ConcurrentLocksDump() : _map(NULL), _last(NULL), _retain_map_on_free(false) {};

  ~ConcurrentLocksDump();

  void                        dump_at_safepoint();

  ThreadConcurrentLocks*      thread_concurrent_locks(JavaThread* thread);

  void                        print_locks_on(JavaThread* t, outputStream* st);

};

class ThreadDumpResult : public StackObj {

 private:

  int                  _num_threads;

  int                  _num_snapshots;

  ThreadSnapshot*      _snapshots;

  ThreadSnapshot*      _last;

  ThreadDumpResult*    _next;

 public:

  ThreadDumpResult();

  ThreadDumpResult(int num_threads);

  ~ThreadDumpResult();

  void                 add_thread_snapshot(ThreadSnapshot* ts);

  void                 set_next(ThreadDumpResult* next) { _next = next; }

  ThreadDumpResult*    next()                           { return _next; }

  int                  num_threads()                    { return _num_threads; }

  int                  num_snapshots()                  { return _num_snapshots; }

  ThreadSnapshot*      snapshots()                      { return _snapshots; }

  void                 oops_do(OopClosure* f);

};

class DeadlockCycle : public CHeapObj {

 private:

  bool _is_deadlock;

  GrowableArray<JavaThread*>* _threads;

  DeadlockCycle*              _next;

 public:

  DeadlockCycle();

  ~DeadlockCycle();

  DeadlockCycle* next()                     { return _next; }

  void           set_next(DeadlockCycle* d) { _next = d; }

  void           add_thread(JavaThread* t)  { _threads->append(t); }

  void           reset()                    { _is_deadlock = false; _threads->clear(); }

  void           set_deadlock(bool value)   { _is_deadlock = value; }

  bool           is_deadlock()              { return _is_deadlock; }

  int            num_threads()              { return _threads->length(); }

  GrowableArray<JavaThread*>* threads()     { return _threads; }

  void           print_on(outputStream* st) const;

};

// Utility class to get list of java threads.

class ThreadsListEnumerator : public StackObj {

private:

  GrowableArray<instanceHandle>* _threads_array;

public:

  ThreadsListEnumerator(Thread* cur_thread,

                        bool include_jvmti_agent_threads = false,

                        bool include_jni_attaching_threads = true);

  int            num_threads()            { return _threads_array->length(); }

  instanceHandle get_threadObj(int index) { return _threads_array->at(index); }

};

// abstract utility class to set new thread states, and restore previous after the block exits

class JavaThreadStatusChanger : public StackObj {

 private:

  java_lang_Thread::ThreadStatus _old_state;

  JavaThread*  _java_thread;

  bool _is_alive;

  void save_old_state(JavaThread* java_thread) {

    _java_thread  = java_thread;

    _is_alive = is_alive(java_thread);

    if (is_alive()) {

      _old_state = java_lang_Thread::get_thread_status(_java_thread->threadObj());

    }

  }

 public:

  static void set_thread_status(JavaThread* java_thread,

                                java_lang_Thread::ThreadStatus state) {

    java_lang_Thread::set_thread_status(java_thread->threadObj(), state);

  }

  void set_thread_status(java_lang_Thread::ThreadStatus state) {

    if (is_alive()) {

      set_thread_status(_java_thread, state);

    }

  }

  JavaThreadStatusChanger(JavaThread* java_thread,

                          java_lang_Thread::ThreadStatus state) {

    save_old_state(java_thread);

    set_thread_status(state);

  }

  JavaThreadStatusChanger(JavaThread* java_thread) {

    save_old_state(java_thread);

  }

  ~JavaThreadStatusChanger() {

    set_thread_status(_old_state);

  }

  static bool is_alive(JavaThread* java_thread) {

    return java_thread != NULL && java_thread->threadObj() != NULL;

  }

  bool is_alive() {

    return _is_alive;

  }

};

// Change status to waiting on an object  (timed or indefinite)

class JavaThreadInObjectWaitState : public JavaThreadStatusChanger {

 private:

  ThreadStatistics* _stat;

  bool _active;

 public:

  JavaThreadInObjectWaitState(JavaThread *java_thread, bool timed) :

    JavaThreadStatusChanger(java_thread,

                            timed ? java_lang_Thread::IN_OBJECT_WAIT_TIMED : java_lang_Thread::IN_OBJECT_WAIT) {

    if (is_alive()) {

      _stat = java_thread->get_thread_stat();

      _active = ThreadService::is_thread_monitoring_contention();

      _stat->monitor_wait();

      if (_active) {

        _stat->monitor_wait_begin();

      }

    } else {

      _active = false;

    }

  }

  ~JavaThreadInObjectWaitState() {

    if (_active) {

      _stat->monitor_wait_end();

    }

  }

};

// Change status to parked (timed or indefinite)

class JavaThreadParkedState : public JavaThreadStatusChanger {

 private:

  ThreadStatistics* _stat;

  bool _active;

 public:

  JavaThreadParkedState(JavaThread *java_thread, bool timed) :

    JavaThreadStatusChanger(java_thread,

                            timed ? java_lang_Thread::PARKED_TIMED : java_lang_Thread::PARKED) {

    if (is_alive()) {

      _stat = java_thread->get_thread_stat();

      _active = ThreadService::is_thread_monitoring_contention();

      _stat->monitor_wait();

      if (_active) {

        _stat->monitor_wait_begin();

      }

    } else {

      _active = false;

    }

  }

  ~JavaThreadParkedState() {

    if (_active) {

      _stat->monitor_wait_end();

    }

  }

};

// Change status to blocked on (re-)entering a synchronization block

class JavaThreadBlockedOnMonitorEnterState : public JavaThreadStatusChanger {

 private:

  ThreadStatistics* _stat;

  bool _active;

  static bool contended_enter_begin(JavaThread *java_thread) {

    set_thread_status(java_thread, java_lang_Thread::BLOCKED_ON_MONITOR_ENTER);

    ThreadStatistics* stat = java_thread->get_thread_stat();

    stat->contended_enter();

    bool active = ThreadService::is_thread_monitoring_contention();

    if (active) {

      stat->contended_enter_begin();

    }

    return active;

  }

 public:

  // java_thread is waiting thread being blocked on monitor reenter.

  // Current thread is the notifying thread which holds the monitor.

  static bool wait_reenter_begin(JavaThread *java_thread, ObjectMonitor *obj_m) {

    assert((java_thread != NULL), "Java thread should not be null here");

    bool active  = false;

    if (is_alive(java_thread) && ServiceUtil::visible_oop((oop)obj_m->object())) {

      active = contended_enter_begin(java_thread);

    }

    return active;

  }

  static void wait_reenter_end(JavaThread *java_thread, bool active) {

    if (active) {

      java_thread->get_thread_stat()->contended_enter_end();

    }

    set_thread_status(java_thread, java_lang_Thread::RUNNABLE);

  }

  JavaThreadBlockedOnMonitorEnterState(JavaThread *java_thread, ObjectMonitor *obj_m) :

    JavaThreadStatusChanger(java_thread) {

    assert((java_thread != NULL), "Java thread should not be null here");

    // Change thread status and collect contended enter stats for monitor contended

    // enter done for external java world objects and it is contended. All other cases

    // like for vm internal objects and for external objects which are not contended

    // thread status is not changed and contended enter stat is not collected.

    _active = false;

    if (is_alive() && ServiceUtil::visible_oop((oop)obj_m->object()) && obj_m->contentions() > 0) {