1 /*
   2  * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/systemDictionary.hpp"
  27 #include "memory/allocation.hpp"
  28 #include "memory/heapInspection.hpp"
  29 #include "memory/oopFactory.hpp"
  30 #include "oops/instanceKlass.hpp"
  31 #include "oops/oop.inline.hpp"
  32 #include "runtime/handles.inline.hpp"
  33 #include "runtime/init.hpp"
  34 #include "runtime/thread.hpp"
  35 #include "runtime/vframe.hpp"
  36 #include "runtime/vmThread.hpp"
  37 #include "runtime/vm_operations.hpp"
  38 #include "services/threadService.hpp"
  39 
  40 // TODO: we need to define a naming convention for perf counters
  41 // to distinguish counters for:
  42 //   - standard JSR174 use
  43 //   - Hotspot extension (public and committed)
  44 //   - Hotspot extension (private/internal and uncommitted)
  45 
  46 // Default is disabled.
  47 bool ThreadService::_thread_monitoring_contention_enabled = false;
  48 bool ThreadService::_thread_cpu_time_enabled = false;
  49 bool ThreadService::_thread_allocated_memory_enabled = false;
  50 
  51 PerfCounter*  ThreadService::_total_threads_count = NULL;
  52 PerfVariable* ThreadService::_live_threads_count = NULL;
  53 PerfVariable* ThreadService::_peak_threads_count = NULL;
  54 PerfVariable* ThreadService::_daemon_threads_count = NULL;
  55 volatile int ThreadService::_exiting_threads_count = 0;
  56 volatile int ThreadService::_exiting_daemon_threads_count = 0;
  57 
  58 ThreadDumpResult* ThreadService::_threaddump_list = NULL;
  59 
  60 static const int INITIAL_ARRAY_SIZE = 10;
  61 
  62 void ThreadService::init() {
  63   EXCEPTION_MARK;
  64 
  65   // These counters are for java.lang.management API support.
  66   // They are created even if -XX:-UsePerfData is set and in
  67   // that case, they will be allocated on C heap.
  68 
  69   _total_threads_count =
  70                 PerfDataManager::create_counter(JAVA_THREADS, "started",
  71                                                 PerfData::U_Events, CHECK);
  72 
  73   _live_threads_count =
  74                 PerfDataManager::create_variable(JAVA_THREADS, "live",
  75                                                  PerfData::U_None, CHECK);
  76 
  77   _peak_threads_count =
  78                 PerfDataManager::create_variable(JAVA_THREADS, "livePeak",
  79                                                  PerfData::U_None, CHECK);
  80 
  81   _daemon_threads_count =
  82                 PerfDataManager::create_variable(JAVA_THREADS, "daemon",
  83                                                  PerfData::U_None, CHECK);
  84 
  85   if (os::is_thread_cpu_time_supported()) {
  86     _thread_cpu_time_enabled = true;
  87   }
  88 
  89   _thread_allocated_memory_enabled = true; // Always on, so enable it
  90 }
  91 
  92 void ThreadService::reset_peak_thread_count() {
  93   // Acquire the lock to update the peak thread count
  94   // to synchronize with thread addition and removal.
  95   MutexLockerEx mu(Threads_lock);
  96   _peak_threads_count->set_value(get_live_thread_count());
  97 }
  98 
  99 void ThreadService::add_thread(JavaThread* thread, bool daemon) {
 100   // Do not count VM internal or JVMTI agent threads
 101   if (thread->is_hidden_from_external_view() ||
 102       thread->is_jvmti_agent_thread()) {
 103     return;
 104   }
 105 
 106   _total_threads_count->inc();
 107   _live_threads_count->inc();
 108 
 109   if (_live_threads_count->get_value() > _peak_threads_count->get_value()) {
 110     _peak_threads_count->set_value(_live_threads_count->get_value());
 111   }
 112 
 113   if (daemon) {
 114     _daemon_threads_count->inc();
 115   }
 116 }
 117 
 118 void ThreadService::remove_thread(JavaThread* thread, bool daemon) {
 119   Atomic::dec((jint*) &_exiting_threads_count);
 120 
 121   if (thread->is_hidden_from_external_view() ||
 122       thread->is_jvmti_agent_thread()) {
 123     return;
 124   }
 125 
 126   _live_threads_count->set_value(_live_threads_count->get_value() - 1);
 127 
 128   if (daemon) {
 129     _daemon_threads_count->set_value(_daemon_threads_count->get_value() - 1);
 130     Atomic::dec((jint*) &_exiting_daemon_threads_count);
 131   }
 132 }
 133 
 134 void ThreadService::current_thread_exiting(JavaThread* jt) {
 135   assert(jt == JavaThread::current(), "Called by current thread");
 136   Atomic::inc((jint*) &_exiting_threads_count);
 137 
 138   oop threadObj = jt->threadObj();
 139   if (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)) {
 140     Atomic::inc((jint*) &_exiting_daemon_threads_count);
 141   }
 142 }
 143 
 144 // FIXME: JVMTI should call this function
 145 Handle ThreadService::get_current_contended_monitor(JavaThread* thread) {
 146   assert(thread != NULL, "should be non-NULL");
 147   assert(Threads_lock->owned_by_self(), "must grab Threads_lock or be at safepoint");
 148 
 149   ObjectMonitor *wait_obj = thread->current_waiting_monitor();
 150 
 151   oop obj = NULL;
 152   if (wait_obj != NULL) {
 153     // thread is doing an Object.wait() call
 154     obj = (oop) wait_obj->object();
 155     assert(obj != NULL, "Object.wait() should have an object");
 156   } else {
 157     ObjectMonitor *enter_obj = thread->current_pending_monitor();
 158     if (enter_obj != NULL) {
 159       // thread is trying to enter() or raw_enter() an ObjectMonitor.
 160       obj = (oop) enter_obj->object();
 161     }
 162     // If obj == NULL, then ObjectMonitor is raw which doesn't count.
 163   }
 164 
 165   Handle h(obj);
 166   return h;
 167 }
 168 
 169 bool ThreadService::set_thread_monitoring_contention(bool flag) {
 170   MutexLocker m(Management_lock);
 171 
 172   bool prev = _thread_monitoring_contention_enabled;
 173   _thread_monitoring_contention_enabled = flag;
 174 
 175   return prev;
 176 }
 177 
 178 bool ThreadService::set_thread_cpu_time_enabled(bool flag) {
 179   MutexLocker m(Management_lock);
 180 
 181   bool prev = _thread_cpu_time_enabled;
 182   _thread_cpu_time_enabled = flag;
 183 
 184   return prev;
 185 }
 186 
 187 bool ThreadService::set_thread_allocated_memory_enabled(bool flag) {
 188   MutexLocker m(Management_lock);
 189 
 190   bool prev = _thread_allocated_memory_enabled;
 191   _thread_allocated_memory_enabled = flag;
 192 
 193   return prev;
 194 }
 195 
 196 // GC support
 197 void ThreadService::oops_do(OopClosure* f) {
 198   for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) {
 199     dump->oops_do(f);
 200   }
 201 }
 202 
 203 void ThreadService::metadata_do(void f(Metadata*)) {
 204   for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) {
 205     dump->metadata_do(f);
 206   }
 207 }
 208 
 209 void ThreadService::add_thread_dump(ThreadDumpResult* dump) {
 210   MutexLocker ml(Management_lock);
 211   if (_threaddump_list == NULL) {
 212     _threaddump_list = dump;
 213   } else {
 214     dump->set_next(_threaddump_list);
 215     _threaddump_list = dump;
 216   }
 217 }
 218 
 219 void ThreadService::remove_thread_dump(ThreadDumpResult* dump) {
 220   MutexLocker ml(Management_lock);
 221 
 222   ThreadDumpResult* prev = NULL;
 223   bool found = false;
 224   for (ThreadDumpResult* d = _threaddump_list; d != NULL; prev = d, d = d->next()) {
 225     if (d == dump) {
 226       if (prev == NULL) {
 227         _threaddump_list = dump->next();
 228       } else {
 229         prev->set_next(dump->next());
 230       }
 231       found = true;
 232       break;
 233     }
 234   }
 235   assert(found, "The threaddump result to be removed must exist.");
 236 }
 237 
 238 // Dump stack trace of threads specified in the given threads array.
 239 // Returns StackTraceElement[][] each element is the stack trace of a thread in
 240 // the corresponding entry in the given threads array
 241 Handle ThreadService::dump_stack_traces(GrowableArray<instanceHandle>* threads,
 242                                         int num_threads,
 243                                         TRAPS) {
 244   assert(num_threads > 0, "just checking");
 245 
 246   ThreadDumpResult dump_result;
 247   VM_ThreadDump op(&dump_result,
 248                    threads,
 249                    num_threads,
 250                    -1,    /* entire stack */
 251                    false, /* with locked monitors */
 252                    false  /* with locked synchronizers */);
 253   VMThread::execute(&op);
 254 
 255   // Allocate the resulting StackTraceElement[][] object
 256 
 257   ResourceMark rm(THREAD);
 258   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_StackTraceElement_array(), true, CHECK_NH);
 259   ObjArrayKlass* ik = ObjArrayKlass::cast(k);
 260   objArrayOop r = oopFactory::new_objArray(ik, num_threads, CHECK_NH);
 261   objArrayHandle result_obj(THREAD, r);
 262 
 263   int num_snapshots = dump_result.num_snapshots();
 264   assert(num_snapshots == num_threads, "Must have num_threads thread snapshots");
 265   int i = 0;
 266   for (ThreadSnapshot* ts = dump_result.snapshots(); ts != NULL; i++, ts = ts->next()) {
 267     ThreadStackTrace* stacktrace = ts->get_stack_trace();
 268     if (stacktrace == NULL) {
 269       // No stack trace
 270       result_obj->obj_at_put(i, NULL);
 271     } else {
 272       // Construct an array of java/lang/StackTraceElement object
 273       Handle backtrace_h = stacktrace->allocate_fill_stack_trace_element_array(CHECK_NH);
 274       result_obj->obj_at_put(i, backtrace_h());
 275     }
 276   }
 277 
 278   return result_obj;
 279 }
 280 
 281 void ThreadService::reset_contention_count_stat(JavaThread* thread) {
 282   ThreadStatistics* stat = thread->get_thread_stat();
 283   if (stat != NULL) {
 284     stat->reset_count_stat();
 285   }
 286 }
 287 
 288 void ThreadService::reset_contention_time_stat(JavaThread* thread) {
 289   ThreadStatistics* stat = thread->get_thread_stat();
 290   if (stat != NULL) {
 291     stat->reset_time_stat();
 292   }
 293 }
 294 
 295 // Find deadlocks involving object monitors and concurrent locks if concurrent_locks is true
 296 DeadlockCycle* ThreadService::find_deadlocks_at_safepoint(bool concurrent_locks) {
 297   // This code was modified from the original Threads::find_deadlocks code.
 298   int globalDfn = 0, thisDfn;
 299   ObjectMonitor* waitingToLockMonitor = NULL;
 300   oop waitingToLockBlocker = NULL;
 301   bool blocked_on_monitor = false;
 302   JavaThread *currentThread, *previousThread;
 303   int num_deadlocks = 0;
 304 
 305   for (JavaThread* p = Threads::first(); p != NULL; p = p->next()) {
 306     // Initialize the depth-first-number
 307     p->set_depth_first_number(-1);
 308   }
 309 
 310   DeadlockCycle* deadlocks = NULL;
 311   DeadlockCycle* last = NULL;
 312   DeadlockCycle* cycle = new DeadlockCycle();
 313   for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
 314     if (jt->depth_first_number() >= 0) {
 315       // this thread was already visited
 316       continue;
 317     }
 318 
 319     thisDfn = globalDfn;
 320     jt->set_depth_first_number(globalDfn++);
 321     previousThread = jt;
 322     currentThread = jt;
 323 
 324     cycle->reset();
 325 
 326     // When there is a deadlock, all the monitors involved in the dependency
 327     // cycle must be contended and heavyweight. So we only care about the
 328     // heavyweight monitor a thread is waiting to lock.
 329     waitingToLockMonitor = (ObjectMonitor*)jt->current_pending_monitor();
 330     if (concurrent_locks) {
 331       waitingToLockBlocker = jt->current_park_blocker();
 332     }
 333     while (waitingToLockMonitor != NULL || waitingToLockBlocker != NULL) {
 334       cycle->add_thread(currentThread);
 335       if (waitingToLockMonitor != NULL) {
 336         address currentOwner = (address)waitingToLockMonitor->owner();
 337         if (currentOwner != NULL) {
 338           currentThread = Threads::owning_thread_from_monitor_owner(
 339                             currentOwner,
 340                             false /* no locking needed */);
 341           if (currentThread == NULL) {
 342             // This function is called at a safepoint so the JavaThread
 343             // that owns waitingToLockMonitor should be findable, but
 344             // if it is not findable, then the previous currentThread is
 345             // blocked permanently. We record this as a deadlock.
 346             num_deadlocks++;
 347 
 348             cycle->set_deadlock(true);
 349 
 350             // add this cycle to the deadlocks list
 351             if (deadlocks == NULL) {
 352               deadlocks = cycle;
 353             } else {
 354               last->set_next(cycle);
 355             }
 356             last = cycle;
 357             cycle = new DeadlockCycle();
 358             break;
 359           }
 360         }
 361       } else {
 362         if (concurrent_locks) {
 363           if (waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
 364             oop threadObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
 365             currentThread = threadObj != NULL ? java_lang_Thread::thread(threadObj) : NULL;
 366           } else {
 367             currentThread = NULL;
 368           }
 369         }
 370       }
 371 
 372       if (currentThread == NULL) {
 373         // No dependency on another thread
 374         break;
 375       }
 376       if (currentThread->depth_first_number() < 0) {
 377         // First visit to this thread
 378         currentThread->set_depth_first_number(globalDfn++);
 379       } else if (currentThread->depth_first_number() < thisDfn) {
 380         // Thread already visited, and not on a (new) cycle
 381         break;
 382       } else if (currentThread == previousThread) {
 383         // Self-loop, ignore
 384         break;
 385       } else {
 386         // We have a (new) cycle
 387         num_deadlocks++;
 388 
 389         cycle->set_deadlock(true);
 390 
 391         // add this cycle to the deadlocks list
 392         if (deadlocks == NULL) {
 393           deadlocks = cycle;
 394         } else {
 395           last->set_next(cycle);
 396         }
 397         last = cycle;
 398         cycle = new DeadlockCycle();
 399         break;
 400       }
 401       previousThread = currentThread;
 402       waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
 403       if (concurrent_locks) {
 404         waitingToLockBlocker = currentThread->current_park_blocker();
 405       }
 406     }
 407 
 408   }
 409   delete cycle;
 410   return deadlocks;
 411 }
 412 
 413 ThreadDumpResult::ThreadDumpResult() : _num_threads(0), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL) {
 414 
 415   // Create a new ThreadDumpResult object and append to the list.
 416   // If GC happens before this function returns, Method*
 417   // in the stack trace will be visited.
 418   ThreadService::add_thread_dump(this);
 419 }
 420 
 421 ThreadDumpResult::ThreadDumpResult(int num_threads) : _num_threads(num_threads), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL) {
 422   // Create a new ThreadDumpResult object and append to the list.
 423   // If GC happens before this function returns, oops
 424   // will be visited.
 425   ThreadService::add_thread_dump(this);
 426 }
 427 
 428 ThreadDumpResult::~ThreadDumpResult() {
 429   ThreadService::remove_thread_dump(this);
 430 
 431   // free all the ThreadSnapshot objects created during
 432   // the VM_ThreadDump operation
 433   ThreadSnapshot* ts = _snapshots;
 434   while (ts != NULL) {
 435     ThreadSnapshot* p = ts;
 436     ts = ts->next();
 437     delete p;
 438   }
 439 }
 440 
 441 
 442 void ThreadDumpResult::add_thread_snapshot(ThreadSnapshot* ts) {
 443   assert(_num_threads == 0 || _num_snapshots < _num_threads,
 444          "_num_snapshots must be less than _num_threads");
 445   _num_snapshots++;
 446   if (_snapshots == NULL) {
 447     _snapshots = ts;
 448   } else {
 449     _last->set_next(ts);
 450   }
 451   _last = ts;
 452 }
 453 
 454 void ThreadDumpResult::oops_do(OopClosure* f) {
 455   for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) {
 456     ts->oops_do(f);
 457   }
 458 }
 459 
 460 void ThreadDumpResult::metadata_do(void f(Metadata*)) {
 461   for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) {
 462     ts->metadata_do(f);
 463   }
 464 }
 465 
 466 StackFrameInfo::StackFrameInfo(javaVFrame* jvf, bool with_lock_info) {
 467   _method = jvf->method();
 468   _bci = jvf->bci();
 469   _class_holder = _method->method_holder()->klass_holder();
 470   _locked_monitors = NULL;
 471   if (with_lock_info) {
 472     ResourceMark rm;
 473     GrowableArray<MonitorInfo*>* list = jvf->locked_monitors();
 474     int length = list->length();
 475     if (length > 0) {
 476       _locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(length, true);
 477       for (int i = 0; i < length; i++) {
 478         MonitorInfo* monitor = list->at(i);
 479         assert(monitor->owner(), "This monitor must have an owning object");
 480         _locked_monitors->append(monitor->owner());
 481       }
 482     }
 483   }
 484 }
 485 
 486 void StackFrameInfo::oops_do(OopClosure* f) {
 487   if (_locked_monitors != NULL) {
 488     int length = _locked_monitors->length();
 489     for (int i = 0; i < length; i++) {
 490       f->do_oop((oop*) _locked_monitors->adr_at(i));
 491     }
 492   }
 493   f->do_oop(&_class_holder);
 494 }
 495 
 496 void StackFrameInfo::metadata_do(void f(Metadata*)) {
 497   f(_method);
 498 }
 499 
 500 void StackFrameInfo::print_on(outputStream* st) const {
 501   ResourceMark rm;
 502   java_lang_Throwable::print_stack_element(st, method(), bci());
 503   int len = (_locked_monitors != NULL ? _locked_monitors->length() : 0);
 504   for (int i = 0; i < len; i++) {
 505     oop o = _locked_monitors->at(i);
 506     InstanceKlass* ik = InstanceKlass::cast(o->klass());
 507     st->print_cr("\t- locked <" INTPTR_FORMAT "> (a %s)", (address)o, ik->external_name());
 508   }
 509 
 510 }
 511 
 512 // Iterate through monitor cache to find JNI locked monitors
 513 class InflatedMonitorsClosure: public MonitorClosure {
 514 private:
 515   ThreadStackTrace* _stack_trace;
 516   Thread* _thread;
 517 public:
 518   InflatedMonitorsClosure(Thread* t, ThreadStackTrace* st) {
 519     _thread = t;
 520     _stack_trace = st;
 521   }
 522   void do_monitor(ObjectMonitor* mid) {
 523     if (mid->owner() == _thread) {
 524       oop object = (oop) mid->object();
 525       if (!_stack_trace->is_owned_monitor_on_stack(object)) {
 526         _stack_trace->add_jni_locked_monitor(object);
 527       }
 528     }
 529   }
 530 };
 531 
 532 ThreadStackTrace::ThreadStackTrace(JavaThread* t, bool with_locked_monitors) {
 533   _thread = t;
 534   _frames = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<StackFrameInfo*>(INITIAL_ARRAY_SIZE, true);
 535   _depth = 0;
 536   _with_locked_monitors = with_locked_monitors;
 537   if (_with_locked_monitors) {
 538     _jni_locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(INITIAL_ARRAY_SIZE, true);
 539   } else {
 540     _jni_locked_monitors = NULL;
 541   }
 542 }
 543 
 544 ThreadStackTrace::~ThreadStackTrace() {
 545   for (int i = 0; i < _frames->length(); i++) {
 546     delete _frames->at(i);
 547   }
 548   delete _frames;
 549   if (_jni_locked_monitors != NULL) {
 550     delete _jni_locked_monitors;
 551   }
 552 }
 553 
 554 void ThreadStackTrace::dump_stack_at_safepoint(int maxDepth) {
 555   assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
 556 
 557   if (_thread->has_last_Java_frame()) {
 558     RegisterMap reg_map(_thread);
 559     vframe* start_vf = _thread->last_java_vframe(&reg_map);
 560     int count = 0;
 561     for (vframe* f = start_vf; f; f = f->sender() ) {
 562       if (f->is_java_frame()) {
 563         javaVFrame* jvf = javaVFrame::cast(f);
 564         add_stack_frame(jvf);
 565         count++;
 566       } else {
 567         // Ignore non-Java frames
 568       }
 569       if (maxDepth > 0 && count == maxDepth) {
 570         // Skip frames if more than maxDepth
 571         break;
 572       }
 573     }
 574   }
 575 
 576   if (_with_locked_monitors) {
 577     // Iterate inflated monitors and find monitors locked by this thread
 578     // not found in the stack
 579     InflatedMonitorsClosure imc(_thread, this);
 580     ObjectSynchronizer::monitors_iterate(&imc);
 581   }
 582 }
 583 
 584 
 585 bool ThreadStackTrace::is_owned_monitor_on_stack(oop object) {
 586   assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
 587 
 588   bool found = false;
 589   int num_frames = get_stack_depth();
 590   for (int depth = 0; depth < num_frames; depth++) {
 591     StackFrameInfo* frame = stack_frame_at(depth);
 592     int len = frame->num_locked_monitors();
 593     GrowableArray<oop>* locked_monitors = frame->locked_monitors();
 594     for (int j = 0; j < len; j++) {
 595       oop monitor = locked_monitors->at(j);
 596       assert(monitor != NULL && monitor->is_instance(), "must be a Java object");
 597       if (monitor == object) {
 598         found = true;
 599         break;
 600       }
 601     }
 602   }
 603   return found;
 604 }
 605 
 606 Handle ThreadStackTrace::allocate_fill_stack_trace_element_array(TRAPS) {
 607   Klass* k = SystemDictionary::StackTraceElement_klass();
 608   assert(k != NULL, "must be loaded in 1.4+");
 609   instanceKlassHandle ik(THREAD, k);
 610 
 611   // Allocate an array of java/lang/StackTraceElement object
 612   objArrayOop ste = oopFactory::new_objArray(ik(), _depth, CHECK_NH);
 613   objArrayHandle backtrace(THREAD, ste);
 614   for (int j = 0; j < _depth; j++) {
 615     StackFrameInfo* frame = _frames->at(j);
 616     methodHandle mh(THREAD, frame->method());
 617     oop element = java_lang_StackTraceElement::create(mh, frame->bci(), CHECK_NH);
 618     backtrace->obj_at_put(j, element);
 619   }
 620   return backtrace;
 621 }
 622 
 623 void ThreadStackTrace::add_stack_frame(javaVFrame* jvf) {
 624   StackFrameInfo* frame = new StackFrameInfo(jvf, _with_locked_monitors);
 625   _frames->append(frame);
 626   _depth++;
 627 }
 628 
 629 void ThreadStackTrace::oops_do(OopClosure* f) {
 630   int length = _frames->length();
 631   for (int i = 0; i < length; i++) {
 632     _frames->at(i)->oops_do(f);
 633   }
 634 
 635   length = (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0);
 636   for (int j = 0; j < length; j++) {
 637     f->do_oop((oop*) _jni_locked_monitors->adr_at(j));
 638   }
 639 }
 640 
 641 void ThreadStackTrace::metadata_do(void f(Metadata*)) {
 642   int length = _frames->length();
 643   for (int i = 0; i < length; i++) {
 644     _frames->at(i)->metadata_do(f);
 645   }
 646 }
 647 
 648 
 649 ConcurrentLocksDump::~ConcurrentLocksDump() {
 650   if (_retain_map_on_free) {
 651     return;
 652   }
 653 
 654   for (ThreadConcurrentLocks* t = _map; t != NULL;)  {
 655     ThreadConcurrentLocks* tcl = t;
 656     t = t->next();
 657     delete tcl;
 658   }
 659 }
 660 
 661 void ConcurrentLocksDump::dump_at_safepoint() {
 662   // dump all locked concurrent locks
 663   assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
 664 
 665   if (JDK_Version::is_gte_jdk16x_version()) {
 666     ResourceMark rm;
 667 
 668     GrowableArray<oop>* aos_objects = new GrowableArray<oop>(INITIAL_ARRAY_SIZE);
 669 
 670     // Find all instances of AbstractOwnableSynchronizer
 671     HeapInspection::find_instances_at_safepoint(SystemDictionary::abstract_ownable_synchronizer_klass(),
 672                                                 aos_objects);
 673     // Build a map of thread to its owned AQS locks
 674     build_map(aos_objects);
 675   }
 676 }
 677 
 678 
 679 // build a map of JavaThread to all its owned AbstractOwnableSynchronizer
 680 void ConcurrentLocksDump::build_map(GrowableArray<oop>* aos_objects) {
 681   int length = aos_objects->length();
 682   for (int i = 0; i < length; i++) {
 683     oop o = aos_objects->at(i);
 684     oop owner_thread_obj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(o);
 685     if (owner_thread_obj != NULL) {
 686       JavaThread* thread = java_lang_Thread::thread(owner_thread_obj);
 687       assert(o->is_instance(), "Must be an instanceOop");
 688       add_lock(thread, (instanceOop) o);
 689     }
 690   }
 691 }
 692 
 693 void ConcurrentLocksDump::add_lock(JavaThread* thread, instanceOop o) {
 694   ThreadConcurrentLocks* tcl = thread_concurrent_locks(thread);
 695   if (tcl != NULL) {
 696     tcl->add_lock(o);
 697     return;
 698   }
 699 
 700   // First owned lock found for this thread
 701   tcl = new ThreadConcurrentLocks(thread);
 702   tcl->add_lock(o);
 703   if (_map == NULL) {
 704     _map = tcl;
 705   } else {
 706     _last->set_next(tcl);
 707   }
 708   _last = tcl;
 709 }
 710 
 711 ThreadConcurrentLocks* ConcurrentLocksDump::thread_concurrent_locks(JavaThread* thread) {
 712   for (ThreadConcurrentLocks* tcl = _map; tcl != NULL; tcl = tcl->next()) {
 713     if (tcl->java_thread() == thread) {
 714       return tcl;
 715     }
 716   }
 717   return NULL;
 718 }
 719 
 720 void ConcurrentLocksDump::print_locks_on(JavaThread* t, outputStream* st) {
 721   st->print_cr("   Locked ownable synchronizers:");
 722   ThreadConcurrentLocks* tcl = thread_concurrent_locks(t);
 723   GrowableArray<instanceOop>* locks = (tcl != NULL ? tcl->owned_locks() : NULL);
 724   if (locks == NULL || locks->is_empty()) {
 725     st->print_cr("\t- None");
 726     st->cr();
 727     return;
 728   }
 729 
 730   for (int i = 0; i < locks->length(); i++) {
 731     instanceOop obj = locks->at(i);
 732     InstanceKlass* ik = InstanceKlass::cast(obj->klass());
 733     st->print_cr("\t- <" INTPTR_FORMAT "> (a %s)", (address)obj, ik->external_name());
 734   }
 735   st->cr();
 736 }
 737 
 738 ThreadConcurrentLocks::ThreadConcurrentLocks(JavaThread* thread) {
 739   _thread = thread;
 740   _owned_locks = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<instanceOop>(INITIAL_ARRAY_SIZE, true);
 741   _next = NULL;
 742 }
 743 
 744 ThreadConcurrentLocks::~ThreadConcurrentLocks() {
 745   delete _owned_locks;
 746 }
 747 
 748 void ThreadConcurrentLocks::add_lock(instanceOop o) {
 749   _owned_locks->append(o);
 750 }
 751 
 752 void ThreadConcurrentLocks::oops_do(OopClosure* f) {
 753   int length = _owned_locks->length();
 754   for (int i = 0; i < length; i++) {
 755     f->do_oop((oop*) _owned_locks->adr_at(i));
 756   }
 757 }
 758 
 759 ThreadStatistics::ThreadStatistics() {
 760   _contended_enter_count = 0;
 761   _monitor_wait_count = 0;
 762   _sleep_count = 0;
 763   _count_pending_reset = false;
 764   _timer_pending_reset = false;
 765   memset((void*) _perf_recursion_counts, 0, sizeof(_perf_recursion_counts));
 766 }
 767 
 768 ThreadSnapshot::ThreadSnapshot(JavaThread* thread) {
 769   _thread = thread;
 770   _threadObj = thread->threadObj();
 771   _stack_trace = NULL;
 772   _concurrent_locks = NULL;
 773   _next = NULL;
 774 
 775   ThreadStatistics* stat = thread->get_thread_stat();
 776   _contended_enter_ticks = stat->contended_enter_ticks();
 777   _contended_enter_count = stat->contended_enter_count();
 778   _monitor_wait_ticks = stat->monitor_wait_ticks();
 779   _monitor_wait_count = stat->monitor_wait_count();
 780   _sleep_ticks = stat->sleep_ticks();
 781   _sleep_count = stat->sleep_count();
 782 
 783   _blocker_object = NULL;
 784   _blocker_object_owner = NULL;
 785 
 786   _thread_status = java_lang_Thread::get_thread_status(_threadObj);
 787   _is_ext_suspended = thread->is_being_ext_suspended();
 788   _is_in_native = (thread->thread_state() == _thread_in_native);
 789 
 790   if (_thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER ||
 791       _thread_status == java_lang_Thread::IN_OBJECT_WAIT ||
 792       _thread_status == java_lang_Thread::IN_OBJECT_WAIT_TIMED) {
 793 
 794     Handle obj = ThreadService::get_current_contended_monitor(thread);
 795     if (obj() == NULL) {
 796       // monitor no longer exists; thread is not blocked
 797       _thread_status = java_lang_Thread::RUNNABLE;
 798     } else {
 799       _blocker_object = obj();
 800       JavaThread* owner = ObjectSynchronizer::get_lock_owner(obj, false);
 801       if ((owner == NULL && _thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER)
 802           || (owner != NULL && owner->is_attaching_via_jni())) {
 803         // ownership information of the monitor is not available
 804         // (may no longer be owned or releasing to some other thread)
 805         // make this thread in RUNNABLE state.
 806         // And when the owner thread is in attaching state, the java thread
 807         // is not completely initialized. For example thread name and id
 808         // and may not be set, so hide the attaching thread.
 809         _thread_status = java_lang_Thread::RUNNABLE;
 810         _blocker_object = NULL;
 811       } else if (owner != NULL) {
 812         _blocker_object_owner = owner->threadObj();
 813       }
 814     }
 815   }
 816 
 817   // Support for JSR-166 locks
 818   if (JDK_Version::current().supports_thread_park_blocker() &&
 819         (_thread_status == java_lang_Thread::PARKED ||
 820          _thread_status == java_lang_Thread::PARKED_TIMED)) {
 821 
 822     _blocker_object = thread->current_park_blocker();
 823     if (_blocker_object != NULL && _blocker_object->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
 824       _blocker_object_owner = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(_blocker_object);
 825     }
 826   }
 827 }
 828 
 829 ThreadSnapshot::~ThreadSnapshot() {
 830   delete _stack_trace;
 831   delete _concurrent_locks;
 832 }
 833 
 834 void ThreadSnapshot::dump_stack_at_safepoint(int max_depth, bool with_locked_monitors) {
 835   _stack_trace = new ThreadStackTrace(_thread, with_locked_monitors);
 836   _stack_trace->dump_stack_at_safepoint(max_depth);
 837 }
 838 
 839 
 840 void ThreadSnapshot::oops_do(OopClosure* f) {
 841   f->do_oop(&_threadObj);
 842   f->do_oop(&_blocker_object);
 843   f->do_oop(&_blocker_object_owner);
 844   if (_stack_trace != NULL) {
 845     _stack_trace->oops_do(f);
 846   }
 847   if (_concurrent_locks != NULL) {
 848     _concurrent_locks->oops_do(f);
 849   }
 850 }
 851 
 852 void ThreadSnapshot::metadata_do(void f(Metadata*)) {
 853   if (_stack_trace != NULL) {
 854     _stack_trace->metadata_do(f);
 855   }
 856 }
 857 
 858 
 859 DeadlockCycle::DeadlockCycle() {
 860   _is_deadlock = false;
 861   _threads = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<JavaThread*>(INITIAL_ARRAY_SIZE, true);
 862   _next = NULL;
 863 }
 864 
 865 DeadlockCycle::~DeadlockCycle() {
 866   delete _threads;
 867 }
 868 
 869 void DeadlockCycle::print_on(outputStream* st) const {
 870   st->cr();
 871   st->print_cr("Found one Java-level deadlock:");
 872   st->print("=============================");
 873 
 874   JavaThread* currentThread;
 875   ObjectMonitor* waitingToLockMonitor;
 876   oop waitingToLockBlocker;
 877   int len = _threads->length();
 878   for (int i = 0; i < len; i++) {
 879     currentThread = _threads->at(i);
 880     waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
 881     waitingToLockBlocker = currentThread->current_park_blocker();
 882     st->cr();
 883     st->print_cr("\"%s\":", currentThread->get_thread_name());
 884     const char* owner_desc = ",\n  which is held by";
 885     if (waitingToLockMonitor != NULL) {
 886       st->print("  waiting to lock monitor " INTPTR_FORMAT, waitingToLockMonitor);
 887       oop obj = (oop)waitingToLockMonitor->object();
 888       if (obj != NULL) {
 889         st->print(" (object "INTPTR_FORMAT ", a %s)", (address)obj,
 890                    (InstanceKlass::cast(obj->klass()))->external_name());
 891 
 892         if (!currentThread->current_pending_monitor_is_from_java()) {
 893           owner_desc = "\n  in JNI, which is held by";
 894         }
 895       } else {
 896         // No Java object associated - a JVMTI raw monitor
 897         owner_desc = " (JVMTI raw monitor),\n  which is held by";
 898       }
 899       currentThread = Threads::owning_thread_from_monitor_owner(
 900                         (address)waitingToLockMonitor->owner(),
 901                         false /* no locking needed */);
 902       if (currentThread == NULL) {
 903         // The deadlock was detected at a safepoint so the JavaThread
 904         // that owns waitingToLockMonitor should be findable, but
 905         // if it is not findable, then the previous currentThread is
 906         // blocked permanently.
 907         st->print("%s UNKNOWN_owner_addr=" PTR_FORMAT, owner_desc,
 908                   (address)waitingToLockMonitor->owner());
 909         continue;
 910       }
 911     } else {
 912       st->print("  waiting for ownable synchronizer " INTPTR_FORMAT ", (a %s)",
 913                 (address)waitingToLockBlocker,
 914                 (InstanceKlass::cast(waitingToLockBlocker->klass()))->external_name());
 915       assert(waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass()),
 916              "Must be an AbstractOwnableSynchronizer");
 917       oop ownerObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
 918       currentThread = java_lang_Thread::thread(ownerObj);
 919     }
 920     st->print("%s \"%s\"", owner_desc, currentThread->get_thread_name());
 921   }
 922 
 923   st->cr();
 924   st->cr();
 925 
 926   // Print stack traces
 927   bool oldJavaMonitorsInStackTrace = JavaMonitorsInStackTrace;
 928   JavaMonitorsInStackTrace = true;
 929   st->print_cr("Java stack information for the threads listed above:");
 930   st->print_cr("===================================================");
 931   for (int j = 0; j < len; j++) {
 932     currentThread = _threads->at(j);
 933     st->print_cr("\"%s\":", currentThread->get_thread_name());
 934     currentThread->print_stack_on(st);
 935   }
 936   JavaMonitorsInStackTrace = oldJavaMonitorsInStackTrace;
 937 }
 938 
 939 ThreadsListEnumerator::ThreadsListEnumerator(Thread* cur_thread,
 940                                              bool include_jvmti_agent_threads,
 941                                              bool include_jni_attaching_threads) {
 942   assert(cur_thread == Thread::current(), "Check current thread");
 943 
 944   int init_size = ThreadService::get_live_thread_count();
 945   _threads_array = new GrowableArray<instanceHandle>(init_size);
 946 
 947   MutexLockerEx ml(Threads_lock);
 948 
 949   for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
 950     // skips JavaThreads in the process of exiting
 951     // and also skips VM internal JavaThreads
 952     // Threads in _thread_new or _thread_new_trans state are included.
 953     // i.e. threads have been started but not yet running.
 954     if (jt->threadObj() == NULL   ||
 955         jt->is_exiting() ||
 956         !java_lang_Thread::is_alive(jt->threadObj())   ||
 957         jt->is_hidden_from_external_view()) {
 958       continue;
 959     }
 960 
 961     // skip agent threads
 962     if (!include_jvmti_agent_threads && jt->is_jvmti_agent_thread()) {
 963       continue;
 964     }
 965 
 966     // skip jni threads in the process of attaching
 967     if (!include_jni_attaching_threads && jt->is_attaching_via_jni()) {
 968       continue;
 969     }
 970 
 971     instanceHandle h(cur_thread, (instanceOop) jt->threadObj());
 972     _threads_array->append(h);
 973   }
 974 }