--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/services/threadService.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,885 @@
+/*
+ * Copyright 2003-2007 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.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_threadService.cpp.incl"
+
+// TODO: we need to define a naming convention for perf counters
+// to distinguish counters for:
+//   - standard JSR174 use
+//   - Hotspot extension (public and committed)
+//   - Hotspot extension (private/internal and uncommitted)
+
+// Default is disabled.
+bool ThreadService::_thread_monitoring_contention_enabled = false;
+bool ThreadService::_thread_cpu_time_enabled = false;
+
+PerfCounter*  ThreadService::_total_threads_count = NULL;
+PerfVariable* ThreadService::_live_threads_count = NULL;
+PerfVariable* ThreadService::_peak_threads_count = NULL;
+PerfVariable* ThreadService::_daemon_threads_count = NULL;
+volatile int ThreadService::_exiting_threads_count = 0;
+volatile int ThreadService::_exiting_daemon_threads_count = 0;
+
+ThreadDumpResult* ThreadService::_threaddump_list = NULL;
+
+static const int INITIAL_ARRAY_SIZE = 10;
+
+void ThreadService::init() {
+  EXCEPTION_MARK;
+
+  // These counters are for java.lang.management API support.
+  // They are created even if -XX:-UsePerfData is set and in
+  // that case, they will be allocated on C heap.
+
+  _total_threads_count =
+                PerfDataManager::create_counter(JAVA_THREADS, "started",
+                                                PerfData::U_Events, CHECK);
+
+  _live_threads_count =
+                PerfDataManager::create_variable(JAVA_THREADS, "live",
+                                                 PerfData::U_None, CHECK);
+
+  _peak_threads_count =
+                PerfDataManager::create_variable(JAVA_THREADS, "livePeak",
+                                                 PerfData::U_None, CHECK);
+
+  _daemon_threads_count =
+                PerfDataManager::create_variable(JAVA_THREADS, "daemon",
+                                                 PerfData::U_None, CHECK);
+
+  if (os::is_thread_cpu_time_supported()) {
+    _thread_cpu_time_enabled = true;
+  }
+}
+
+void ThreadService::reset_peak_thread_count() {
+  // Acquire the lock to update the peak thread count
+  // to synchronize with thread addition and removal.
+  MutexLockerEx mu(Threads_lock);
+  _peak_threads_count->set_value(get_live_thread_count());
+}
+
+void ThreadService::add_thread(JavaThread* thread, bool daemon) {
+  // Do not count VM internal or JVMTI agent threads
+  if (thread->is_hidden_from_external_view() ||
+      thread->is_jvmti_agent_thread()) {
+    return;
+  }
+
+  _total_threads_count->inc();
+  _live_threads_count->inc();
+
+  if (_live_threads_count->get_value() > _peak_threads_count->get_value()) {
+    _peak_threads_count->set_value(_live_threads_count->get_value());
+  }
+
+  if (daemon) {
+    _daemon_threads_count->inc();
+  }
+}
+
+void ThreadService::remove_thread(JavaThread* thread, bool daemon) {
+  Atomic::dec((jint*) &_exiting_threads_count);
+
+  if (thread->is_hidden_from_external_view() ||
+      thread->is_jvmti_agent_thread()) {
+    return;
+  }
+
+  _live_threads_count->set_value(_live_threads_count->get_value() - 1);
+
+  if (daemon) {
+    _daemon_threads_count->set_value(_daemon_threads_count->get_value() - 1);
+    Atomic::dec((jint*) &_exiting_daemon_threads_count);
+  }
+}
+
+void ThreadService::current_thread_exiting(JavaThread* jt) {
+  assert(jt == JavaThread::current(), "Called by current thread");
+  Atomic::inc((jint*) &_exiting_threads_count);
+
+  oop threadObj = jt->threadObj();
+  if (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)) {
+    Atomic::inc((jint*) &_exiting_daemon_threads_count);
+  }
+}
+
+// FIXME: JVMTI should call this function
+Handle ThreadService::get_current_contended_monitor(JavaThread* thread) {
+  assert(thread != NULL, "should be non-NULL");
+  assert(Threads_lock->owned_by_self(), "must grab Threads_lock or be at safepoint");
+
+  ObjectMonitor *wait_obj = thread->current_waiting_monitor();
+
+  oop obj = NULL;
+  if (wait_obj != NULL) {
+    // thread is doing an Object.wait() call
+    obj = (oop) wait_obj->object();
+    assert(obj != NULL, "Object.wait() should have an object");
+  } else {
+    ObjectMonitor *enter_obj = thread->current_pending_monitor();
+    if (enter_obj != NULL) {
+      // thread is trying to enter() or raw_enter() an ObjectMonitor.
+      obj = (oop) enter_obj->object();
+    }
+    // If obj == NULL, then ObjectMonitor is raw which doesn't count.
+  }
+
+  Handle h(obj);
+  return h;
+}
+
+bool ThreadService::set_thread_monitoring_contention(bool flag) {
+  MutexLocker m(Management_lock);
+
+  bool prev = _thread_monitoring_contention_enabled;
+  _thread_monitoring_contention_enabled = flag;
+
+  return prev;
+}
+
+bool ThreadService::set_thread_cpu_time_enabled(bool flag) {
+  MutexLocker m(Management_lock);
+
+  bool prev = _thread_cpu_time_enabled;
+  _thread_cpu_time_enabled = flag;
+
+  return prev;
+}
+
+// GC support
+void ThreadService::oops_do(OopClosure* f) {
+  for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) {
+    dump->oops_do(f);
+  }
+}
+
+void ThreadService::add_thread_dump(ThreadDumpResult* dump) {
+  MutexLocker ml(Management_lock);
+  if (_threaddump_list == NULL) {
+    _threaddump_list = dump;
+  } else {
+    dump->set_next(_threaddump_list);
+    _threaddump_list = dump;
+  }
+}
+
+void ThreadService::remove_thread_dump(ThreadDumpResult* dump) {
+  MutexLocker ml(Management_lock);
+
+  ThreadDumpResult* prev = NULL;
+  bool found = false;
+  for (ThreadDumpResult* d = _threaddump_list; d != NULL; prev = d, d = d->next()) {
+    if (d == dump) {
+      if (prev == NULL) {
+        _threaddump_list = dump->next();
+      } else {
+        prev->set_next(dump->next());
+      }
+      found = true;
+      break;
+    }
+  }
+  assert(found, "The threaddump result to be removed must exist.");
+}
+
+// Dump stack trace of threads specified in the given threads array.
+// Returns StackTraceElement[][] each element is the stack trace of a thread in
+// the corresponding entry in the given threads array
+Handle ThreadService::dump_stack_traces(GrowableArray<instanceHandle>* threads,
+                                        int num_threads,
+                                        TRAPS) {
+  assert(num_threads > 0, "just checking");
+
+  ThreadDumpResult dump_result;
+  VM_ThreadDump op(&dump_result,
+                   threads,
+                   num_threads,
+                   -1,    /* entire stack */
+                   false, /* with locked monitors */
+                   false  /* with locked synchronizers */);
+  VMThread::execute(&op);
+
+  // Allocate the resulting StackTraceElement[][] object
+
+  ResourceMark rm(THREAD);
+  klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_StackTraceElement_array(), true, CHECK_NH);
+  objArrayKlassHandle ik (THREAD, k);
+  objArrayOop r = oopFactory::new_objArray(ik(), num_threads, CHECK_NH);
+  objArrayHandle result_obj(THREAD, r);
+
+  int num_snapshots = dump_result.num_snapshots();
+  assert(num_snapshots == num_threads, "Must have num_threads thread snapshots");
+  int i = 0;
+  for (ThreadSnapshot* ts = dump_result.snapshots(); ts != NULL; i++, ts = ts->next()) {
+    ThreadStackTrace* stacktrace = ts->get_stack_trace();
+    if (stacktrace == NULL) {
+      // No stack trace
+      result_obj->obj_at_put(i, NULL);
+    } else {
+      // Construct an array of java/lang/StackTraceElement object
+      Handle backtrace_h = stacktrace->allocate_fill_stack_trace_element_array(CHECK_NH);
+      result_obj->obj_at_put(i, backtrace_h());
+    }
+  }
+
+  return result_obj;
+}
+
+void ThreadService::reset_contention_count_stat(JavaThread* thread) {
+  ThreadStatistics* stat = thread->get_thread_stat();
+  if (stat != NULL) {
+    stat->reset_count_stat();
+  }
+}
+
+void ThreadService::reset_contention_time_stat(JavaThread* thread) {
+  ThreadStatistics* stat = thread->get_thread_stat();
+  if (stat != NULL) {
+    stat->reset_time_stat();
+  }
+}
+
+// Find deadlocks involving object monitors and concurrent locks if concurrent_locks is true
+DeadlockCycle* ThreadService::find_deadlocks_at_safepoint(bool concurrent_locks) {
+  // This code was modified from the original Threads::find_deadlocks code.
+  int globalDfn = 0, thisDfn;
+  ObjectMonitor* waitingToLockMonitor = NULL;
+  oop waitingToLockBlocker = NULL;
+  bool blocked_on_monitor = false;
+  JavaThread *currentThread, *previousThread;
+  int num_deadlocks = 0;
+
+  for (JavaThread* p = Threads::first(); p != NULL; p = p->next()) {
+    // Initialize the depth-first-number
+    p->set_depth_first_number(-1);
+  }
+
+  DeadlockCycle* deadlocks = NULL;
+  DeadlockCycle* last = NULL;
+  DeadlockCycle* cycle = new DeadlockCycle();
+  for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
+    if (jt->depth_first_number() >= 0) {
+      // this thread was already visited
+      continue;
+    }
+
+    thisDfn = globalDfn;
+    jt->set_depth_first_number(globalDfn++);
+    previousThread = jt;
+    currentThread = jt;
+
+    cycle->reset();
+
+    // When there is a deadlock, all the monitors involved in the dependency
+    // cycle must be contended and heavyweight. So we only care about the
+    // heavyweight monitor a thread is waiting to lock.
+    waitingToLockMonitor = (ObjectMonitor*)jt->current_pending_monitor();
+    if (concurrent_locks) {
+      waitingToLockBlocker = jt->current_park_blocker();
+    }
+    while (waitingToLockMonitor != NULL || waitingToLockBlocker != NULL) {
+      cycle->add_thread(currentThread);
+      if (waitingToLockMonitor != NULL) {
+        currentThread = Threads::owning_thread_from_monitor_owner((address)waitingToLockMonitor->owner(),
+                                                                  false /* no locking needed */);
+      } else {
+        if (concurrent_locks) {
+          if (waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
+            oop threadObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
+            currentThread = threadObj != NULL ? java_lang_Thread::thread(threadObj) : NULL;
+          } else {
+            currentThread = NULL;
+          }
+        }
+      }
+
+      if (currentThread == NULL) {
+        // No dependency on another thread
+        break;
+      }
+      if (currentThread->depth_first_number() < 0) {
+        // First visit to this thread
+        currentThread->set_depth_first_number(globalDfn++);
+      } else if (currentThread->depth_first_number() < thisDfn) {
+        // Thread already visited, and not on a (new) cycle
+        break;
+      } else if (currentThread == previousThread) {
+        // Self-loop, ignore
+        break;
+      } else {
+        // We have a (new) cycle
+        num_deadlocks++;
+
+        cycle->set_deadlock(true);
+
+        // add this cycle to the deadlocks list
+        if (deadlocks == NULL) {
+          deadlocks = cycle;
+        } else {
+          last->set_next(cycle);
+        }
+        last = cycle;
+        cycle = new DeadlockCycle();
+        break;
+      }
+      previousThread = currentThread;
+      waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
+      if (concurrent_locks) {
+        waitingToLockBlocker = currentThread->current_park_blocker();
+      }
+    }
+
+  }
+
+  return deadlocks;
+}
+
+ThreadDumpResult::ThreadDumpResult() : _num_threads(0), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL) {
+
+  // Create a new ThreadDumpResult object and append to the list.
+  // If GC happens before this function returns, methodOop
+  // in the stack trace will be visited.
+  ThreadService::add_thread_dump(this);
+}
+
+ThreadDumpResult::ThreadDumpResult(int num_threads) : _num_threads(num_threads), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL) {
+  // Create a new ThreadDumpResult object and append to the list.
+  // If GC happens before this function returns, oops
+  // will be visited.
+  ThreadService::add_thread_dump(this);
+}
+
+ThreadDumpResult::~ThreadDumpResult() {
+  ThreadService::remove_thread_dump(this);
+
+  // free all the ThreadSnapshot objects created during
+  // the VM_ThreadDump operation
+  ThreadSnapshot* ts = _snapshots;
+  while (ts != NULL) {
+    ThreadSnapshot* p = ts;
+    ts = ts->next();
+    delete p;
+  }
+}
+
+
+void ThreadDumpResult::add_thread_snapshot(ThreadSnapshot* ts) {
+  assert(_num_threads == 0 || _num_snapshots < _num_threads,
+         "_num_snapshots must be less than _num_threads");
+  _num_snapshots++;
+  if (_snapshots == NULL) {
+    _snapshots = ts;
+  } else {
+    _last->set_next(ts);
+  }
+  _last = ts;
+}
+
+void ThreadDumpResult::oops_do(OopClosure* f) {
+  for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) {
+    ts->oops_do(f);
+  }
+}
+
+StackFrameInfo::StackFrameInfo(javaVFrame* jvf, bool with_lock_info) {
+  _method = jvf->method();
+  _bci = jvf->bci();
+  _locked_monitors = NULL;
+  if (with_lock_info) {
+    ResourceMark rm;
+    GrowableArray<MonitorInfo*>* list = jvf->locked_monitors();
+    int length = list->length();
+    if (length > 0) {
+      _locked_monitors = new (ResourceObj::C_HEAP) GrowableArray<oop>(length, true);
+      for (int i = 0; i < length; i++) {
+        MonitorInfo* monitor = list->at(i);
+        assert(monitor->owner(), "This monitor must have an owning object");
+        _locked_monitors->append(monitor->owner());
+      }
+    }
+  }
+}
+
+void StackFrameInfo::oops_do(OopClosure* f) {
+  f->do_oop((oop*) &_method);
+  if (_locked_monitors != NULL) {
+    int length = _locked_monitors->length();
+    for (int i = 0; i < length; i++) {
+      f->do_oop((oop*) _locked_monitors->adr_at(i));
+    }
+  }
+}
+
+void StackFrameInfo::print_on(outputStream* st) const {
+  ResourceMark rm;
+  java_lang_Throwable::print_stack_element(st, method(), bci());
+  int len = (_locked_monitors != NULL ? _locked_monitors->length() : 0);
+  for (int i = 0; i < len; i++) {
+    oop o = _locked_monitors->at(i);
+    instanceKlass* ik = instanceKlass::cast(o->klass());
+    st->print_cr("\t- locked <" INTPTR_FORMAT "> (a %s)", (address)o, ik->external_name());
+  }
+
+}
+
+// Iterate through monitor cache to find JNI locked monitors
+class InflatedMonitorsClosure: public MonitorClosure {
+private:
+  ThreadStackTrace* _stack_trace;
+  Thread* _thread;
+public:
+  InflatedMonitorsClosure(Thread* t, ThreadStackTrace* st) {
+    _thread = t;
+    _stack_trace = st;
+  }
+  void do_monitor(ObjectMonitor* mid) {
+    if (mid->owner() == _thread) {
+      oop object = (oop) mid->object();
+      if (!_stack_trace->is_owned_monitor_on_stack(object)) {
+        _stack_trace->add_jni_locked_monitor(object);
+      }
+    }
+  }
+};
+
+ThreadStackTrace::ThreadStackTrace(JavaThread* t, bool with_locked_monitors) {
+  _thread = t;
+  _frames = new (ResourceObj::C_HEAP) GrowableArray<StackFrameInfo*>(INITIAL_ARRAY_SIZE, true);
+  _depth = 0;
+  _with_locked_monitors = with_locked_monitors;
+  if (_with_locked_monitors) {
+    _jni_locked_monitors = new (ResourceObj::C_HEAP) GrowableArray<oop>(INITIAL_ARRAY_SIZE, true);
+  } else {
+    _jni_locked_monitors = NULL;
+  }
+}
+
+ThreadStackTrace::~ThreadStackTrace() {
+  for (int i = 0; i < _frames->length(); i++) {
+    delete _frames->at(i);
+  }
+  delete _frames;
+  if (_jni_locked_monitors != NULL) {
+    delete _jni_locked_monitors;
+  }
+}
+
+void ThreadStackTrace::dump_stack_at_safepoint(int maxDepth) {
+  assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
+
+  if (_thread->has_last_Java_frame()) {
+    RegisterMap reg_map(_thread);
+    vframe* start_vf = _thread->last_java_vframe(&reg_map);
+    int count = 0;
+    for (vframe* f = start_vf; f; f = f->sender() ) {
+      if (f->is_java_frame()) {
+        javaVFrame* jvf = javaVFrame::cast(f);
+        add_stack_frame(jvf);
+        count++;
+      } else {
+        // Ignore non-Java frames
+      }
+      if (maxDepth > 0 && count == maxDepth) {
+        // Skip frames if more than maxDepth
+        break;
+      }
+    }
+  }
+
+  if (_with_locked_monitors) {
+    // Iterate inflated monitors and find monitors locked by this thread
+    // not found in the stack
+    InflatedMonitorsClosure imc(_thread, this);
+    ObjectSynchronizer::monitors_iterate(&imc);
+  }
+}
+
+
+bool ThreadStackTrace::is_owned_monitor_on_stack(oop object) {
+  assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
+
+  bool found = false;
+  int num_frames = get_stack_depth();
+  for (int depth = 0; depth < num_frames; depth++) {
+    StackFrameInfo* frame = stack_frame_at(depth);
+    int len = frame->num_locked_monitors();
+    GrowableArray<oop>* locked_monitors = frame->locked_monitors();
+    for (int j = 0; j < len; j++) {
+      oop monitor = locked_monitors->at(j);
+      assert(monitor != NULL && monitor->is_instance(), "must be a Java object");
+      if (monitor == object) {
+        found = true;
+        break;
+      }
+    }
+  }
+  return found;
+}
+
+Handle ThreadStackTrace::allocate_fill_stack_trace_element_array(TRAPS) {
+  klassOop k = SystemDictionary::stackTraceElement_klass();
+  instanceKlassHandle ik(THREAD, k);
+
+  // Allocate an array of java/lang/StackTraceElement object
+  objArrayOop ste = oopFactory::new_objArray(ik(), _depth, CHECK_NH);
+  objArrayHandle backtrace(THREAD, ste);
+  for (int j = 0; j < _depth; j++) {
+    StackFrameInfo* frame = _frames->at(j);
+    methodHandle mh(THREAD, frame->method());
+    oop element = java_lang_StackTraceElement::create(mh, frame->bci(), CHECK_NH);
+    backtrace->obj_at_put(j, element);
+  }
+  return backtrace;
+}
+
+void ThreadStackTrace::add_stack_frame(javaVFrame* jvf) {
+  StackFrameInfo* frame = new StackFrameInfo(jvf, _with_locked_monitors);
+  _frames->append(frame);
+  _depth++;
+}
+
+void ThreadStackTrace::oops_do(OopClosure* f) {
+  int length = _frames->length();
+  for (int i = 0; i < length; i++) {
+    _frames->at(i)->oops_do(f);
+  }
+
+  length = (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0);
+  for (int j = 0; j < length; j++) {
+    f->do_oop((oop*) _jni_locked_monitors->adr_at(j));
+  }
+}
+
+ConcurrentLocksDump::~ConcurrentLocksDump() {
+  if (_retain_map_on_free) {
+    return;
+  }
+
+  for (ThreadConcurrentLocks* t = _map; t != NULL;)  {
+    ThreadConcurrentLocks* tcl = t;
+    t = t->next();
+    delete tcl;
+  }
+}
+
+void ConcurrentLocksDump::dump_at_safepoint() {
+  // dump all locked concurrent locks
+  assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
+
+  if (JDK_Version::is_gte_jdk16x_version()) {
+    ResourceMark rm;
+
+    GrowableArray<oop>* aos_objects = new GrowableArray<oop>(INITIAL_ARRAY_SIZE);
+
+    // Find all instances of AbstractOwnableSynchronizer
+    HeapInspection::find_instances_at_safepoint(SystemDictionary::abstract_ownable_synchronizer_klass(),
+                                                aos_objects);
+    // Build a map of thread to its owned AQS locks
+    build_map(aos_objects);
+  }
+}
+
+
+// build a map of JavaThread to all its owned AbstractOwnableSynchronizer
+void ConcurrentLocksDump::build_map(GrowableArray<oop>* aos_objects) {
+  int length = aos_objects->length();
+  for (int i = 0; i < length; i++) {
+    oop o = aos_objects->at(i);
+    oop owner_thread_obj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(o);
+    if (owner_thread_obj != NULL) {
+      JavaThread* thread = java_lang_Thread::thread(owner_thread_obj);
+      assert(o->is_instance(), "Must be an instanceOop");
+      add_lock(thread, (instanceOop) o);
+    }
+  }
+}
+
+void ConcurrentLocksDump::add_lock(JavaThread* thread, instanceOop o) {
+  ThreadConcurrentLocks* tcl = thread_concurrent_locks(thread);
+  if (tcl != NULL) {
+    tcl->add_lock(o);
+    return;
+  }
+
+  // First owned lock found for this thread
+  tcl = new ThreadConcurrentLocks(thread);
+  tcl->add_lock(o);
+  if (_map == NULL) {
+    _map = tcl;
+  } else {
+    _last->set_next(tcl);
+  }
+  _last = tcl;
+}
+
+ThreadConcurrentLocks* ConcurrentLocksDump::thread_concurrent_locks(JavaThread* thread) {
+  for (ThreadConcurrentLocks* tcl = _map; tcl != NULL; tcl = tcl->next()) {
+    if (tcl->java_thread() == thread) {
+      return tcl;
+    }
+  }
+  return NULL;
+}
+
+void ConcurrentLocksDump::print_locks_on(JavaThread* t, outputStream* st) {
+  st->print_cr("   Locked ownable synchronizers:");
+  ThreadConcurrentLocks* tcl = thread_concurrent_locks(t);
+  GrowableArray<instanceOop>* locks = (tcl != NULL ? tcl->owned_locks() : NULL);
+  if (locks == NULL || locks->is_empty()) {
+    st->print_cr("\t- None");
+    st->cr();
+    return;
+  }
+
+  for (int i = 0; i < locks->length(); i++) {
+    instanceOop obj = locks->at(i);
+    instanceKlass* ik = instanceKlass::cast(obj->klass());
+    st->print_cr("\t- <" INTPTR_FORMAT "> (a %s)", (address)obj, ik->external_name());
+  }
+  st->cr();
+}
+
+ThreadConcurrentLocks::ThreadConcurrentLocks(JavaThread* thread) {
+  _thread = thread;
+  _owned_locks = new (ResourceObj::C_HEAP) GrowableArray<instanceOop>(INITIAL_ARRAY_SIZE, true);
+  _next = NULL;
+}
+
+ThreadConcurrentLocks::~ThreadConcurrentLocks() {
+  delete _owned_locks;
+}
+
+void ThreadConcurrentLocks::add_lock(instanceOop o) {
+  _owned_locks->append(o);
+}
+
+void ThreadConcurrentLocks::oops_do(OopClosure* f) {
+  int length = _owned_locks->length();
+  for (int i = 0; i < length; i++) {
+    f->do_oop((oop*) _owned_locks->adr_at(i));
+  }
+}
+
+ThreadStatistics::ThreadStatistics() {
+  _contended_enter_count = 0;
+  _monitor_wait_count = 0;
+  _sleep_count = 0;
+  _class_init_recursion_count = 0;
+  _class_verify_recursion_count = 0;
+  _count_pending_reset = false;
+  _timer_pending_reset = false;
+}
+
+ThreadSnapshot::ThreadSnapshot(JavaThread* thread) {
+  _thread = thread;
+  _threadObj = thread->threadObj();
+  _stack_trace = NULL;
+  _concurrent_locks = NULL;
+  _next = NULL;
+
+  ThreadStatistics* stat = thread->get_thread_stat();
+  _contended_enter_ticks = stat->contended_enter_ticks();
+  _contended_enter_count = stat->contended_enter_count();
+  _monitor_wait_ticks = stat->monitor_wait_ticks();
+  _monitor_wait_count = stat->monitor_wait_count();
+  _sleep_ticks = stat->sleep_ticks();
+  _sleep_count = stat->sleep_count();
+
+  _blocker_object = NULL;
+  _blocker_object_owner = NULL;
+
+  _thread_status = java_lang_Thread::get_thread_status(_threadObj);
+  _is_ext_suspended = thread->is_being_ext_suspended();
+  _is_in_native = (thread->thread_state() == _thread_in_native);
+
+  if (_thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER ||
+      _thread_status == java_lang_Thread::IN_OBJECT_WAIT ||
+      _thread_status == java_lang_Thread::IN_OBJECT_WAIT_TIMED) {
+
+    Handle obj = ThreadService::get_current_contended_monitor(thread);
+    if (obj() == NULL) {
+      // monitor no longer exists; thread is not blocked
+      _thread_status = java_lang_Thread::RUNNABLE;
+    } else {
+      _blocker_object = obj();
+      JavaThread* owner = ObjectSynchronizer::get_lock_owner(obj, false);
+      if ((owner == NULL && _thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER)
+          || (owner != NULL && owner->is_attaching())) {
+        // ownership information of the monitor is not available
+        // (may no longer be owned or releasing to some other thread)
+        // make this thread in RUNNABLE state.
+        // And when the owner thread is in attaching state, the java thread
+        // is not completely initialized. For example thread name and id
+        // and may not be set, so hide the attaching thread.
+        _thread_status = java_lang_Thread::RUNNABLE;
+        _blocker_object = NULL;
+      } else if (owner != NULL) {
+        _blocker_object_owner = owner->threadObj();
+      }
+    }
+  }
+
+  // Support for JSR-166 locks
+  if (JDK_Version::supports_thread_park_blocker() &&
+        (_thread_status == java_lang_Thread::PARKED ||
+         _thread_status == java_lang_Thread::PARKED_TIMED)) {
+
+    _blocker_object = thread->current_park_blocker();
+    if (_blocker_object != NULL && _blocker_object->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
+      _blocker_object_owner = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(_blocker_object);
+    }
+  }
+}
+
+ThreadSnapshot::~ThreadSnapshot() {
+  delete _stack_trace;
+  delete _concurrent_locks;
+}
+
+void ThreadSnapshot::dump_stack_at_safepoint(int max_depth, bool with_locked_monitors) {
+  _stack_trace = new ThreadStackTrace(_thread, with_locked_monitors);
+  _stack_trace->dump_stack_at_safepoint(max_depth);
+}
+
+
+void ThreadSnapshot::oops_do(OopClosure* f) {
+  f->do_oop(&_threadObj);
+  f->do_oop(&_blocker_object);
+  f->do_oop(&_blocker_object_owner);
+  if (_stack_trace != NULL) {
+    _stack_trace->oops_do(f);
+  }
+  if (_concurrent_locks != NULL) {
+    _concurrent_locks->oops_do(f);
+  }
+}
+
+DeadlockCycle::DeadlockCycle() {
+  _is_deadlock = false;
+  _threads = new (ResourceObj::C_HEAP) GrowableArray<JavaThread*>(INITIAL_ARRAY_SIZE, true);
+  _next = NULL;
+}
+
+DeadlockCycle::~DeadlockCycle() {
+  delete _threads;
+}
+
+void DeadlockCycle::print_on(outputStream* st) const {
+  st->cr();
+  st->print_cr("Found one Java-level deadlock:");
+  st->print("=============================");
+
+  JavaThread* currentThread;
+  ObjectMonitor* waitingToLockMonitor;
+  oop waitingToLockBlocker;
+  int len = _threads->length();
+  for (int i = 0; i < len; i++) {
+    currentThread = _threads->at(i);
+    waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
+    waitingToLockBlocker = currentThread->current_park_blocker();
+    st->cr();
+    st->print_cr("\"%s\":", currentThread->get_thread_name());
+    const char* owner_desc = ",\n  which is held by";
+    if (waitingToLockMonitor != NULL) {
+      st->print("  waiting to lock monitor " INTPTR_FORMAT, waitingToLockMonitor);
+      oop obj = (oop)waitingToLockMonitor->object();
+      if (obj != NULL) {
+        st->print(" (object "INTPTR_FORMAT ", a %s)", (address)obj,
+                   (instanceKlass::cast(obj->klass()))->external_name());
+
+        if (!currentThread->current_pending_monitor_is_from_java()) {
+          owner_desc = "\n  in JNI, which is held by";
+        }
+      } else {
+        // No Java object associated - a JVMTI raw monitor
+        owner_desc = " (JVMTI raw monitor),\n  which is held by";
+      }
+      currentThread = Threads::owning_thread_from_monitor_owner(
+        (address)waitingToLockMonitor->owner(), false /* no locking needed */);
+    } else {
+      st->print("  waiting for ownable synchronizer " INTPTR_FORMAT ", (a %s)",
+                (address)waitingToLockBlocker,
+                (instanceKlass::cast(waitingToLockBlocker->klass()))->external_name());
+      assert(waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass()),
+             "Must be an AbstractOwnableSynchronizer");
+      oop ownerObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
+      currentThread = java_lang_Thread::thread(ownerObj);
+    }
+    st->print("%s \"%s\"", owner_desc, currentThread->get_thread_name());
+  }
+
+  st->cr();
+  st->cr();
+
+  // Print stack traces
+  bool oldJavaMonitorsInStackTrace = JavaMonitorsInStackTrace;
+  JavaMonitorsInStackTrace = true;
+  st->print_cr("Java stack information for the threads listed above:");
+  st->print_cr("===================================================");
+  for (int j = 0; j < len; j++) {
+    currentThread = _threads->at(j);
+    st->print_cr("\"%s\":", currentThread->get_thread_name());
+    currentThread->print_stack_on(st);
+  }
+  JavaMonitorsInStackTrace = oldJavaMonitorsInStackTrace;
+}
+
+ThreadsListEnumerator::ThreadsListEnumerator(Thread* cur_thread,
+                                             bool include_jvmti_agent_threads,
+                                             bool include_jni_attaching_threads) {
+  assert(cur_thread == Thread::current(), "Check current thread");
+
+  int init_size = ThreadService::get_live_thread_count();
+  _threads_array = new GrowableArray<instanceHandle>(init_size);
+
+  MutexLockerEx ml(Threads_lock);
+
+  for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
+    // skips JavaThreads in the process of exiting
+    // and also skips VM internal JavaThreads
+    // Threads in _thread_new or _thread_new_trans state are included.
+    // i.e. threads have been started but not yet running.
+    if (jt->threadObj() == NULL   ||
+        jt->is_exiting() ||
+        !java_lang_Thread::is_alive(jt->threadObj())   ||
+        jt->is_hidden_from_external_view()) {
+      continue;
+    }
+
+    // skip agent threads
+    if (!include_jvmti_agent_threads && jt->is_jvmti_agent_thread()) {
+      continue;
+    }
+
+    // skip jni threads in the process of attaching
+    if (!include_jni_attaching_threads && jt->is_attaching()) {
+      continue;
+    }
+
+    instanceHandle h(cur_thread, (instanceOop) jt->threadObj());
+    _threads_array->append(h);
+  }
+}