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 /*

  * Copyright (c) 2003, 2010, 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

  * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #ifndef SHARE_VM_SERVICES_THREADSERVICE_HPP

 #define SHARE_VM_SERVICES_THREADSERVICE_HPP

 #include "classfile/javaClasses.hpp"

 #include "runtime/handles.hpp"

 #include "runtime/init.hpp"

 #include "runtime/jniHandles.hpp"

 #include "runtime/objectMonitor.hpp"

 #include "runtime/objectMonitor.inline.hpp"

 #include "runtime/perfData.hpp"

 #include "services/management.hpp"

 #include "services/serviceUtil.hpp"

 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) {

       _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();

     }

   }

 };

 #endif // SHARE_VM_SERVICES_THREADSERVICE_HPP