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hotspot/src/share/vm/services/threadService.hpp

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+/*
+ * Copyright 2003-2006 Sun Microsystems, Inc.  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
+ * 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.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+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          _class_init_recursion_count;
+  int          _class_verify_recursion_count;
+  int          _class_link_recursion_count;
+
+  // 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* class_init_recursion_count_addr()   { return &_class_init_recursion_count; }
+  int* class_verify_recursion_count_addr() { return &_class_verify_recursion_count; }
+  int* class_link_recursion_count_addr()   { return &_class_link_recursion_count; }
+};
+
+// 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();
+
+  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) {
+      _stat = java_thread->get_thread_stat();
+      _active = contended_enter_begin(java_thread);
+    }
+  }
+
+  ~JavaThreadBlockedOnMonitorEnterState() {
+    if (_active) {
+      _stat->contended_enter_end();
+    }
+  }
+};
+
+// Change status to sleeping
+class JavaThreadSleepState : public JavaThreadStatusChanger {
+ private:
+  ThreadStatistics* _stat;
+  bool _active;
+ public:
+  JavaThreadSleepState(JavaThread *java_thread) :
+    JavaThreadStatusChanger(java_thread, java_lang_Thread::SLEEPING) {
+    if (is_alive()) {
+      _stat = java_thread->get_thread_stat();
+      _active = ThreadService::is_thread_monitoring_contention();
+      _stat->thread_sleep();
+      if (_active) {
+        _stat->thread_sleep_begin();
+      }
+    } else {
+      _active = false;
+    }
+  }
+
+  ~JavaThreadSleepState() {
+    if (_active) {
+      _stat->thread_sleep_end();
+    }
+  }
+};