1 /*
2 * Copyright (c) 2003, 2009, 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 "incls/_precompiled.incl"
26 # include "incls/_threadService.cpp.incl"
27
28 // TODO: we need to define a naming convention for perf counters
29 // to distinguish counters for:
30 // - standard JSR174 use
31 // - Hotspot extension (public and committed)
32 // - Hotspot extension (private/internal and uncommitted)
33
34 // Default is disabled.
35 bool ThreadService::_thread_monitoring_contention_enabled = false;
36 bool ThreadService::_thread_cpu_time_enabled = false;
37
38 PerfCounter* ThreadService::_total_threads_count = NULL;
39 PerfVariable* ThreadService::_live_threads_count = NULL;
40 PerfVariable* ThreadService::_peak_threads_count = NULL;
41 PerfVariable* ThreadService::_daemon_threads_count = NULL;
42 volatile int ThreadService::_exiting_threads_count = 0;
43 volatile int ThreadService::_exiting_daemon_threads_count = 0;
44
45 ThreadDumpResult* ThreadService::_threaddump_list = NULL;
46
47 static const int INITIAL_ARRAY_SIZE = 10;
48
49 void ThreadService::init() {
50 EXCEPTION_MARK;
51
52 // These counters are for java.lang.management API support.
53 // They are created even if -XX:-UsePerfData is set and in
54 // that case, they will be allocated on C heap.
55
56 _total_threads_count =
57 PerfDataManager::create_counter(JAVA_THREADS, "started",
58 PerfData::U_Events, CHECK);
59
60 _live_threads_count =
61 PerfDataManager::create_variable(JAVA_THREADS, "live",
62 PerfData::U_None, CHECK);
63
64 _peak_threads_count =
65 PerfDataManager::create_variable(JAVA_THREADS, "livePeak",
66 PerfData::U_None, CHECK);
67
68 _daemon_threads_count =
69 PerfDataManager::create_variable(JAVA_THREADS, "daemon",
70 PerfData::U_None, CHECK);
71
72 if (os::is_thread_cpu_time_supported()) {
73 _thread_cpu_time_enabled = true;
74 }
75 }
76
77 void ThreadService::reset_peak_thread_count() {
78 // Acquire the lock to update the peak thread count
79 // to synchronize with thread addition and removal.
80 MutexLockerEx mu(Threads_lock);
81 _peak_threads_count->set_value(get_live_thread_count());
82 }
83
84 void ThreadService::add_thread(JavaThread* thread, bool daemon) {
85 // Do not count VM internal or JVMTI agent threads
86 if (thread->is_hidden_from_external_view() ||
87 thread->is_jvmti_agent_thread()) {
88 return;
89 }
90
91 _total_threads_count->inc();
92 _live_threads_count->inc();
93
94 if (_live_threads_count->get_value() > _peak_threads_count->get_value()) {
95 _peak_threads_count->set_value(_live_threads_count->get_value());
96 }
97
98 if (daemon) {
99 _daemon_threads_count->inc();
100 }
101 }
102
103 void ThreadService::remove_thread(JavaThread* thread, bool daemon) {
104 Atomic::dec((jint*) &_exiting_threads_count);
105
106 if (thread->is_hidden_from_external_view() ||
107 thread->is_jvmti_agent_thread()) {
108 return;
109 }
110
111 _live_threads_count->set_value(_live_threads_count->get_value() - 1);
112
113 if (daemon) {
114 _daemon_threads_count->set_value(_daemon_threads_count->get_value() - 1);
115 Atomic::dec((jint*) &_exiting_daemon_threads_count);
116 }
117 }
118
119 void ThreadService::current_thread_exiting(JavaThread* jt) {
120 assert(jt == JavaThread::current(), "Called by current thread");
121 Atomic::inc((jint*) &_exiting_threads_count);
122
123 oop threadObj = jt->threadObj();
124 if (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)) {
125 Atomic::inc((jint*) &_exiting_daemon_threads_count);
126 }
127 }
128
129 // FIXME: JVMTI should call this function
130 Handle ThreadService::get_current_contended_monitor(JavaThread* thread) {
131 assert(thread != NULL, "should be non-NULL");
132 assert(Threads_lock->owned_by_self(), "must grab Threads_lock or be at safepoint");
133
134 ObjectMonitor *wait_obj = thread->current_waiting_monitor();
135
136 oop obj = NULL;
137 if (wait_obj != NULL) {
138 // thread is doing an Object.wait() call
139 obj = (oop) wait_obj->object();
140 assert(obj != NULL, "Object.wait() should have an object");
141 } else {
142 ObjectMonitor *enter_obj = thread->current_pending_monitor();
143 if (enter_obj != NULL) {
144 // thread is trying to enter() or raw_enter() an ObjectMonitor.
145 obj = (oop) enter_obj->object();
146 }
147 // If obj == NULL, then ObjectMonitor is raw which doesn't count.
148 }
149
150 Handle h(obj);
151 return h;
152 }
153
154 bool ThreadService::set_thread_monitoring_contention(bool flag) {
155 MutexLocker m(Management_lock);
156
157 bool prev = _thread_monitoring_contention_enabled;
158 _thread_monitoring_contention_enabled = flag;
159
160 return prev;
161 }
162
163 bool ThreadService::set_thread_cpu_time_enabled(bool flag) {
164 MutexLocker m(Management_lock);
165
166 bool prev = _thread_cpu_time_enabled;
167 _thread_cpu_time_enabled = flag;
168
169 return prev;
170 }
171
172 // GC support
173 void ThreadService::oops_do(OopClosure* f) {
174 for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) {
175 dump->oops_do(f);
176 }
177 }
178
179 void ThreadService::add_thread_dump(ThreadDumpResult* dump) {
180 MutexLocker ml(Management_lock);
181 if (_threaddump_list == NULL) {
182 _threaddump_list = dump;
183 } else {
184 dump->set_next(_threaddump_list);
185 _threaddump_list = dump;
186 }
187 }
188
189 void ThreadService::remove_thread_dump(ThreadDumpResult* dump) {
190 MutexLocker ml(Management_lock);
191
192 ThreadDumpResult* prev = NULL;
193 bool found = false;
194 for (ThreadDumpResult* d = _threaddump_list; d != NULL; prev = d, d = d->next()) {
195 if (d == dump) {
196 if (prev == NULL) {
197 _threaddump_list = dump->next();
198 } else {
199 prev->set_next(dump->next());
200 }
201 found = true;
202 break;
203 }
204 }
205 assert(found, "The threaddump result to be removed must exist.");
206 }
207
208 // Dump stack trace of threads specified in the given threads array.
209 // Returns StackTraceElement[][] each element is the stack trace of a thread in
210 // the corresponding entry in the given threads array
211 Handle ThreadService::dump_stack_traces(GrowableArray<instanceHandle>* threads,
212 int num_threads,
213 TRAPS) {
214 assert(num_threads > 0, "just checking");
215
216 ThreadDumpResult dump_result;
217 VM_ThreadDump op(&dump_result,
218 threads,
219 num_threads,
220 -1, /* entire stack */
221 false, /* with locked monitors */
222 false /* with locked synchronizers */);
223 VMThread::execute(&op);
224
225 // Allocate the resulting StackTraceElement[][] object
226
227 ResourceMark rm(THREAD);
228 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_StackTraceElement_array(), true, CHECK_NH);
229 objArrayKlassHandle ik (THREAD, k);
230 objArrayOop r = oopFactory::new_objArray(ik(), num_threads, CHECK_NH);
231 objArrayHandle result_obj(THREAD, r);
232
233 int num_snapshots = dump_result.num_snapshots();
234 assert(num_snapshots == num_threads, "Must have num_threads thread snapshots");
235 int i = 0;
236 for (ThreadSnapshot* ts = dump_result.snapshots(); ts != NULL; i++, ts = ts->next()) {
237 ThreadStackTrace* stacktrace = ts->get_stack_trace();
238 if (stacktrace == NULL) {
239 // No stack trace
240 result_obj->obj_at_put(i, NULL);
241 } else {
242 // Construct an array of java/lang/StackTraceElement object
243 Handle backtrace_h = stacktrace->allocate_fill_stack_trace_element_array(CHECK_NH);
244 result_obj->obj_at_put(i, backtrace_h());
245 }
246 }
247
248 return result_obj;
249 }
250
251 void ThreadService::reset_contention_count_stat(JavaThread* thread) {
252 ThreadStatistics* stat = thread->get_thread_stat();
253 if (stat != NULL) {
254 stat->reset_count_stat();
255 }
256 }
257
258 void ThreadService::reset_contention_time_stat(JavaThread* thread) {
259 ThreadStatistics* stat = thread->get_thread_stat();
260 if (stat != NULL) {
261 stat->reset_time_stat();
262 }
263 }
264
265 // Find deadlocks involving object monitors and concurrent locks if concurrent_locks is true
266 DeadlockCycle* ThreadService::find_deadlocks_at_safepoint(bool concurrent_locks) {
267 // This code was modified from the original Threads::find_deadlocks code.
268 int globalDfn = 0, thisDfn;
269 ObjectMonitor* waitingToLockMonitor = NULL;
270 oop waitingToLockBlocker = NULL;
271 bool blocked_on_monitor = false;
272 JavaThread *currentThread, *previousThread;
273 int num_deadlocks = 0;
274
275 for (JavaThread* p = Threads::first(); p != NULL; p = p->next()) {
276 // Initialize the depth-first-number
277 p->set_depth_first_number(-1);
278 }
279
280 DeadlockCycle* deadlocks = NULL;
281 DeadlockCycle* last = NULL;
282 DeadlockCycle* cycle = new DeadlockCycle();
283 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
284 if (jt->depth_first_number() >= 0) {
285 // this thread was already visited
286 continue;
287 }
288
289 thisDfn = globalDfn;
290 jt->set_depth_first_number(globalDfn++);
291 previousThread = jt;
292 currentThread = jt;
293
294 cycle->reset();
295
296 // When there is a deadlock, all the monitors involved in the dependency
297 // cycle must be contended and heavyweight. So we only care about the
298 // heavyweight monitor a thread is waiting to lock.
299 waitingToLockMonitor = (ObjectMonitor*)jt->current_pending_monitor();
300 if (concurrent_locks) {
301 waitingToLockBlocker = jt->current_park_blocker();
302 }
303 while (waitingToLockMonitor != NULL || waitingToLockBlocker != NULL) {
304 cycle->add_thread(currentThread);
305 if (waitingToLockMonitor != NULL) {
306 currentThread = Threads::owning_thread_from_monitor_owner((address)waitingToLockMonitor->owner(),
307 false /* no locking needed */);
308 } else {
309 if (concurrent_locks) {
310 if (waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
311 oop threadObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
312 currentThread = threadObj != NULL ? java_lang_Thread::thread(threadObj) : NULL;
313 } else {
314 currentThread = NULL;
315 }
316 }
317 }
318
319 if (currentThread == NULL) {
320 // No dependency on another thread
321 break;
322 }
323 if (currentThread->depth_first_number() < 0) {
324 // First visit to this thread
325 currentThread->set_depth_first_number(globalDfn++);
326 } else if (currentThread->depth_first_number() < thisDfn) {
327 // Thread already visited, and not on a (new) cycle
328 break;
329 } else if (currentThread == previousThread) {
330 // Self-loop, ignore
331 break;
332 } else {
333 // We have a (new) cycle
334 num_deadlocks++;
335
336 cycle->set_deadlock(true);
337
338 // add this cycle to the deadlocks list
339 if (deadlocks == NULL) {
340 deadlocks = cycle;
341 } else {
342 last->set_next(cycle);
343 }
344 last = cycle;
345 cycle = new DeadlockCycle();
346 break;
347 }
348 previousThread = currentThread;
349 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
350 if (concurrent_locks) {
351 waitingToLockBlocker = currentThread->current_park_blocker();
352 }
353 }
354
355 }
356
357 return deadlocks;
358 }
359
360 ThreadDumpResult::ThreadDumpResult() : _num_threads(0), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL) {
361
362 // Create a new ThreadDumpResult object and append to the list.
363 // If GC happens before this function returns, methodOop
364 // in the stack trace will be visited.
365 ThreadService::add_thread_dump(this);
366 }
367
368 ThreadDumpResult::ThreadDumpResult(int num_threads) : _num_threads(num_threads), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL) {
369 // Create a new ThreadDumpResult object and append to the list.
370 // If GC happens before this function returns, oops
371 // will be visited.
372 ThreadService::add_thread_dump(this);
373 }
374
375 ThreadDumpResult::~ThreadDumpResult() {
376 ThreadService::remove_thread_dump(this);
377
378 // free all the ThreadSnapshot objects created during
379 // the VM_ThreadDump operation
380 ThreadSnapshot* ts = _snapshots;
381 while (ts != NULL) {
382 ThreadSnapshot* p = ts;
383 ts = ts->next();
384 delete p;
385 }
386 }
387
388
389 void ThreadDumpResult::add_thread_snapshot(ThreadSnapshot* ts) {
390 assert(_num_threads == 0 || _num_snapshots < _num_threads,
391 "_num_snapshots must be less than _num_threads");
392 _num_snapshots++;
393 if (_snapshots == NULL) {
394 _snapshots = ts;
395 } else {
396 _last->set_next(ts);
397 }
398 _last = ts;
399 }
400
401 void ThreadDumpResult::oops_do(OopClosure* f) {
402 for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) {
403 ts->oops_do(f);
404 }
405 }
406
407 StackFrameInfo::StackFrameInfo(javaVFrame* jvf, bool with_lock_info) {
408 _method = jvf->method();
409 _bci = jvf->bci();
410 _locked_monitors = NULL;
411 if (with_lock_info) {
412 ResourceMark rm;
413 GrowableArray<MonitorInfo*>* list = jvf->locked_monitors();
414 int length = list->length();
415 if (length > 0) {
416 _locked_monitors = new (ResourceObj::C_HEAP) GrowableArray<oop>(length, true);
417 for (int i = 0; i < length; i++) {
418 MonitorInfo* monitor = list->at(i);
419 assert(monitor->owner(), "This monitor must have an owning object");
420 _locked_monitors->append(monitor->owner());
421 }
422 }
423 }
424 }
425
426 void StackFrameInfo::oops_do(OopClosure* f) {
427 f->do_oop((oop*) &_method);
428 if (_locked_monitors != NULL) {
429 int length = _locked_monitors->length();
430 for (int i = 0; i < length; i++) {
431 f->do_oop((oop*) _locked_monitors->adr_at(i));
432 }
433 }
434 }
435
436 void StackFrameInfo::print_on(outputStream* st) const {
437 ResourceMark rm;
438 java_lang_Throwable::print_stack_element(st, method(), bci());
439 int len = (_locked_monitors != NULL ? _locked_monitors->length() : 0);
440 for (int i = 0; i < len; i++) {
441 oop o = _locked_monitors->at(i);
442 instanceKlass* ik = instanceKlass::cast(o->klass());
443 st->print_cr("\t- locked <" INTPTR_FORMAT "> (a %s)", (address)o, ik->external_name());
444 }
445
446 }
447
448 // Iterate through monitor cache to find JNI locked monitors
449 class InflatedMonitorsClosure: public MonitorClosure {
450 private:
451 ThreadStackTrace* _stack_trace;
452 Thread* _thread;
453 public:
454 InflatedMonitorsClosure(Thread* t, ThreadStackTrace* st) {
455 _thread = t;
456 _stack_trace = st;
457 }
458 void do_monitor(ObjectMonitor* mid) {
459 if (mid->owner() == _thread) {
460 oop object = (oop) mid->object();
461 if (!_stack_trace->is_owned_monitor_on_stack(object)) {
462 _stack_trace->add_jni_locked_monitor(object);
463 }
464 }
465 }
466 };
467
468 ThreadStackTrace::ThreadStackTrace(JavaThread* t, bool with_locked_monitors) {
469 _thread = t;
470 _frames = new (ResourceObj::C_HEAP) GrowableArray<StackFrameInfo*>(INITIAL_ARRAY_SIZE, true);
471 _depth = 0;
472 _with_locked_monitors = with_locked_monitors;
473 if (_with_locked_monitors) {
474 _jni_locked_monitors = new (ResourceObj::C_HEAP) GrowableArray<oop>(INITIAL_ARRAY_SIZE, true);
475 } else {
476 _jni_locked_monitors = NULL;
477 }
478 }
479
480 ThreadStackTrace::~ThreadStackTrace() {
481 for (int i = 0; i < _frames->length(); i++) {
482 delete _frames->at(i);
483 }
484 delete _frames;
485 if (_jni_locked_monitors != NULL) {
486 delete _jni_locked_monitors;
487 }
488 }
489
490 void ThreadStackTrace::dump_stack_at_safepoint(int maxDepth) {
491 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
492
493 if (_thread->has_last_Java_frame()) {
494 RegisterMap reg_map(_thread);
495 vframe* start_vf = _thread->last_java_vframe(®_map);
496 int count = 0;
497 for (vframe* f = start_vf; f; f = f->sender() ) {
498 if (f->is_java_frame()) {
499 javaVFrame* jvf = javaVFrame::cast(f);
500 add_stack_frame(jvf);
501 count++;
502 } else {
503 // Ignore non-Java frames
504 }
505 if (maxDepth > 0 && count == maxDepth) {
506 // Skip frames if more than maxDepth
507 break;
508 }
509 }
510 }
511
512 if (_with_locked_monitors) {
513 // Iterate inflated monitors and find monitors locked by this thread
514 // not found in the stack
515 InflatedMonitorsClosure imc(_thread, this);
516 ObjectSynchronizer::monitors_iterate(&imc);
517 }
518 }
519
520
521 bool ThreadStackTrace::is_owned_monitor_on_stack(oop object) {
522 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
523
524 bool found = false;
525 int num_frames = get_stack_depth();
526 for (int depth = 0; depth < num_frames; depth++) {
527 StackFrameInfo* frame = stack_frame_at(depth);
528 int len = frame->num_locked_monitors();
529 GrowableArray<oop>* locked_monitors = frame->locked_monitors();
530 for (int j = 0; j < len; j++) {
531 oop monitor = locked_monitors->at(j);
532 assert(monitor != NULL && monitor->is_instance(), "must be a Java object");
533 if (monitor == object) {
534 found = true;
535 break;
536 }
537 }
538 }
539 return found;
540 }
541
542 Handle ThreadStackTrace::allocate_fill_stack_trace_element_array(TRAPS) {
543 klassOop k = SystemDictionary::StackTraceElement_klass();
544 assert(k != NULL, "must be loaded in 1.4+");
545 instanceKlassHandle ik(THREAD, k);
546
547 // Allocate an array of java/lang/StackTraceElement object
548 objArrayOop ste = oopFactory::new_objArray(ik(), _depth, CHECK_NH);
549 objArrayHandle backtrace(THREAD, ste);
550 for (int j = 0; j < _depth; j++) {
551 StackFrameInfo* frame = _frames->at(j);
552 methodHandle mh(THREAD, frame->method());
553 oop element = java_lang_StackTraceElement::create(mh, frame->bci(), CHECK_NH);
554 backtrace->obj_at_put(j, element);
555 }
556 return backtrace;
557 }
558
559 void ThreadStackTrace::add_stack_frame(javaVFrame* jvf) {
560 StackFrameInfo* frame = new StackFrameInfo(jvf, _with_locked_monitors);
561 _frames->append(frame);
562 _depth++;
563 }
564
565 void ThreadStackTrace::oops_do(OopClosure* f) {
566 int length = _frames->length();
567 for (int i = 0; i < length; i++) {
568 _frames->at(i)->oops_do(f);
569 }
570
571 length = (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0);
572 for (int j = 0; j < length; j++) {
573 f->do_oop((oop*) _jni_locked_monitors->adr_at(j));
574 }
575 }
576
577 ConcurrentLocksDump::~ConcurrentLocksDump() {
578 if (_retain_map_on_free) {
579 return;
580 }
581
582 for (ThreadConcurrentLocks* t = _map; t != NULL;) {
583 ThreadConcurrentLocks* tcl = t;
584 t = t->next();
585 delete tcl;
586 }
587 }
588
589 void ConcurrentLocksDump::dump_at_safepoint() {
590 // dump all locked concurrent locks
591 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
592
593 if (JDK_Version::is_gte_jdk16x_version()) {
594 ResourceMark rm;
595
596 GrowableArray<oop>* aos_objects = new GrowableArray<oop>(INITIAL_ARRAY_SIZE);
597
598 // Find all instances of AbstractOwnableSynchronizer
599 HeapInspection::find_instances_at_safepoint(SystemDictionary::abstract_ownable_synchronizer_klass(),
600 aos_objects);
601 // Build a map of thread to its owned AQS locks
602 build_map(aos_objects);
603 }
604 }
605
606
607 // build a map of JavaThread to all its owned AbstractOwnableSynchronizer
608 void ConcurrentLocksDump::build_map(GrowableArray<oop>* aos_objects) {
609 int length = aos_objects->length();
610 for (int i = 0; i < length; i++) {
611 oop o = aos_objects->at(i);
612 oop owner_thread_obj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(o);
613 if (owner_thread_obj != NULL) {
614 JavaThread* thread = java_lang_Thread::thread(owner_thread_obj);
615 assert(o->is_instance(), "Must be an instanceOop");
616 add_lock(thread, (instanceOop) o);
617 }
618 }
619 }
620
621 void ConcurrentLocksDump::add_lock(JavaThread* thread, instanceOop o) {
622 ThreadConcurrentLocks* tcl = thread_concurrent_locks(thread);
623 if (tcl != NULL) {
624 tcl->add_lock(o);
625 return;
626 }
627
628 // First owned lock found for this thread
629 tcl = new ThreadConcurrentLocks(thread);
630 tcl->add_lock(o);
631 if (_map == NULL) {
632 _map = tcl;
633 } else {
634 _last->set_next(tcl);
635 }
636 _last = tcl;
637 }
638
639 ThreadConcurrentLocks* ConcurrentLocksDump::thread_concurrent_locks(JavaThread* thread) {
640 for (ThreadConcurrentLocks* tcl = _map; tcl != NULL; tcl = tcl->next()) {
641 if (tcl->java_thread() == thread) {
642 return tcl;
643 }
644 }
645 return NULL;
646 }
647
648 void ConcurrentLocksDump::print_locks_on(JavaThread* t, outputStream* st) {
649 st->print_cr(" Locked ownable synchronizers:");
650 ThreadConcurrentLocks* tcl = thread_concurrent_locks(t);
651 GrowableArray<instanceOop>* locks = (tcl != NULL ? tcl->owned_locks() : NULL);
652 if (locks == NULL || locks->is_empty()) {
653 st->print_cr("\t- None");
654 st->cr();
655 return;
656 }
657
658 for (int i = 0; i < locks->length(); i++) {
659 instanceOop obj = locks->at(i);
660 instanceKlass* ik = instanceKlass::cast(obj->klass());
661 st->print_cr("\t- <" INTPTR_FORMAT "> (a %s)", (address)obj, ik->external_name());
662 }
663 st->cr();
664 }
665
666 ThreadConcurrentLocks::ThreadConcurrentLocks(JavaThread* thread) {
667 _thread = thread;
668 _owned_locks = new (ResourceObj::C_HEAP) GrowableArray<instanceOop>(INITIAL_ARRAY_SIZE, true);
669 _next = NULL;
670 }
671
672 ThreadConcurrentLocks::~ThreadConcurrentLocks() {
673 delete _owned_locks;
674 }
675
676 void ThreadConcurrentLocks::add_lock(instanceOop o) {
677 _owned_locks->append(o);
678 }
679
680 void ThreadConcurrentLocks::oops_do(OopClosure* f) {
681 int length = _owned_locks->length();
682 for (int i = 0; i < length; i++) {
683 f->do_oop((oop*) _owned_locks->adr_at(i));
684 }
685 }
686
687 ThreadStatistics::ThreadStatistics() {
688 _contended_enter_count = 0;
689 _monitor_wait_count = 0;
690 _sleep_count = 0;
691 _count_pending_reset = false;
692 _timer_pending_reset = false;
693 memset((void*) _perf_recursion_counts, 0, sizeof(_perf_recursion_counts));
694 }
695
696 ThreadSnapshot::ThreadSnapshot(JavaThread* thread) {
697 _thread = thread;
698 _threadObj = thread->threadObj();
699 _stack_trace = NULL;
700 _concurrent_locks = NULL;
701 _next = NULL;
702
703 ThreadStatistics* stat = thread->get_thread_stat();
704 _contended_enter_ticks = stat->contended_enter_ticks();
705 _contended_enter_count = stat->contended_enter_count();
706 _monitor_wait_ticks = stat->monitor_wait_ticks();
707 _monitor_wait_count = stat->monitor_wait_count();
708 _sleep_ticks = stat->sleep_ticks();
709 _sleep_count = stat->sleep_count();
710
711 _blocker_object = NULL;
712 _blocker_object_owner = NULL;
713
714 _thread_status = java_lang_Thread::get_thread_status(_threadObj);
715 _is_ext_suspended = thread->is_being_ext_suspended();
716 _is_in_native = (thread->thread_state() == _thread_in_native);
717
718 if (_thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER ||
719 _thread_status == java_lang_Thread::IN_OBJECT_WAIT ||
720 _thread_status == java_lang_Thread::IN_OBJECT_WAIT_TIMED) {
721
722 Handle obj = ThreadService::get_current_contended_monitor(thread);
723 if (obj() == NULL) {
724 // monitor no longer exists; thread is not blocked
725 _thread_status = java_lang_Thread::RUNNABLE;
726 } else {
727 _blocker_object = obj();
728 JavaThread* owner = ObjectSynchronizer::get_lock_owner(obj, false);
729 if ((owner == NULL && _thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER)
730 || (owner != NULL && owner->is_attaching())) {
731 // ownership information of the monitor is not available
732 // (may no longer be owned or releasing to some other thread)
733 // make this thread in RUNNABLE state.
734 // And when the owner thread is in attaching state, the java thread
735 // is not completely initialized. For example thread name and id
736 // and may not be set, so hide the attaching thread.
737 _thread_status = java_lang_Thread::RUNNABLE;
738 _blocker_object = NULL;
739 } else if (owner != NULL) {
740 _blocker_object_owner = owner->threadObj();
741 }
742 }
743 }
744
745 // Support for JSR-166 locks
746 if (JDK_Version::current().supports_thread_park_blocker() &&
747 (_thread_status == java_lang_Thread::PARKED ||
748 _thread_status == java_lang_Thread::PARKED_TIMED)) {
749
750 _blocker_object = thread->current_park_blocker();
751 if (_blocker_object != NULL && _blocker_object->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
752 _blocker_object_owner = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(_blocker_object);
753 }
754 }
755 }
756
757 ThreadSnapshot::~ThreadSnapshot() {
758 delete _stack_trace;
759 delete _concurrent_locks;
760 }
761
762 void ThreadSnapshot::dump_stack_at_safepoint(int max_depth, bool with_locked_monitors) {
763 _stack_trace = new ThreadStackTrace(_thread, with_locked_monitors);
764 _stack_trace->dump_stack_at_safepoint(max_depth);
765 }
766
767
768 void ThreadSnapshot::oops_do(OopClosure* f) {
769 f->do_oop(&_threadObj);
770 f->do_oop(&_blocker_object);
771 f->do_oop(&_blocker_object_owner);
772 if (_stack_trace != NULL) {
773 _stack_trace->oops_do(f);
774 }
775 if (_concurrent_locks != NULL) {
776 _concurrent_locks->oops_do(f);
777 }
778 }
779
780 DeadlockCycle::DeadlockCycle() {
781 _is_deadlock = false;
782 _threads = new (ResourceObj::C_HEAP) GrowableArray<JavaThread*>(INITIAL_ARRAY_SIZE, true);
783 _next = NULL;
784 }
785
786 DeadlockCycle::~DeadlockCycle() {
787 delete _threads;
788 }
789
790 void DeadlockCycle::print_on(outputStream* st) const {
791 st->cr();
792 st->print_cr("Found one Java-level deadlock:");
793 st->print("=============================");
794
795 JavaThread* currentThread;
796 ObjectMonitor* waitingToLockMonitor;
797 oop waitingToLockBlocker;
798 int len = _threads->length();
799 for (int i = 0; i < len; i++) {
800 currentThread = _threads->at(i);
801 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
802 waitingToLockBlocker = currentThread->current_park_blocker();
803 st->cr();
804 st->print_cr("\"%s\":", currentThread->get_thread_name());
805 const char* owner_desc = ",\n which is held by";
806 if (waitingToLockMonitor != NULL) {
807 st->print(" waiting to lock monitor " INTPTR_FORMAT, waitingToLockMonitor);
808 oop obj = (oop)waitingToLockMonitor->object();
809 if (obj != NULL) {
810 st->print(" (object "INTPTR_FORMAT ", a %s)", (address)obj,
811 (instanceKlass::cast(obj->klass()))->external_name());
812
813 if (!currentThread->current_pending_monitor_is_from_java()) {
814 owner_desc = "\n in JNI, which is held by";
815 }
816 } else {
817 // No Java object associated - a JVMTI raw monitor
818 owner_desc = " (JVMTI raw monitor),\n which is held by";
819 }
820 currentThread = Threads::owning_thread_from_monitor_owner(
821 (address)waitingToLockMonitor->owner(), false /* no locking needed */);
822 } else {
823 st->print(" waiting for ownable synchronizer " INTPTR_FORMAT ", (a %s)",
824 (address)waitingToLockBlocker,
825 (instanceKlass::cast(waitingToLockBlocker->klass()))->external_name());
826 assert(waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass()),
827 "Must be an AbstractOwnableSynchronizer");
828 oop ownerObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
829 currentThread = java_lang_Thread::thread(ownerObj);
830 }
831 st->print("%s \"%s\"", owner_desc, currentThread->get_thread_name());
832 }
833
834 st->cr();
835 st->cr();
836
837 // Print stack traces
838 bool oldJavaMonitorsInStackTrace = JavaMonitorsInStackTrace;
839 JavaMonitorsInStackTrace = true;
840 st->print_cr("Java stack information for the threads listed above:");
841 st->print_cr("===================================================");
842 for (int j = 0; j < len; j++) {
843 currentThread = _threads->at(j);
844 st->print_cr("\"%s\":", currentThread->get_thread_name());
845 currentThread->print_stack_on(st);
846 }
847 JavaMonitorsInStackTrace = oldJavaMonitorsInStackTrace;
848 }
849
850 ThreadsListEnumerator::ThreadsListEnumerator(Thread* cur_thread,
851 bool include_jvmti_agent_threads,
852 bool include_jni_attaching_threads) {
853 assert(cur_thread == Thread::current(), "Check current thread");
854
855 int init_size = ThreadService::get_live_thread_count();
856 _threads_array = new GrowableArray<instanceHandle>(init_size);
857
858 MutexLockerEx ml(Threads_lock);
859
860 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
861 // skips JavaThreads in the process of exiting
862 // and also skips VM internal JavaThreads
863 // Threads in _thread_new or _thread_new_trans state are included.
864 // i.e. threads have been started but not yet running.
865 if (jt->threadObj() == NULL ||
866 jt->is_exiting() ||
867 !java_lang_Thread::is_alive(jt->threadObj()) ||
868 jt->is_hidden_from_external_view()) {
869 continue;
870 }
871
872 // skip agent threads
873 if (!include_jvmti_agent_threads && jt->is_jvmti_agent_thread()) {
874 continue;
875 }
876
877 // skip jni threads in the process of attaching
878 if (!include_jni_attaching_threads && jt->is_attaching()) {
879 continue;
880 }
881
882 instanceHandle h(cur_thread, (instanceOop) jt->threadObj());
883 _threads_array->append(h);
884 }
885 }