1 /*
2 * Copyright (c) 2003, 2010, 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
50 PerfCounter* ThreadService::_total_threads_count = NULL;
51 PerfVariable* ThreadService::_live_threads_count = NULL;
52 PerfVariable* ThreadService::_peak_threads_count = NULL;
53 PerfVariable* ThreadService::_daemon_threads_count = NULL;
54 volatile int ThreadService::_exiting_threads_count = 0;
55 volatile int ThreadService::_exiting_daemon_threads_count = 0;
56
57 ThreadDumpResult* ThreadService::_threaddump_list = NULL;
58
59 static const int INITIAL_ARRAY_SIZE = 10;
60
61 void ThreadService::init() {
62 EXCEPTION_MARK;
63
64 // These counters are for java.lang.management API support.
65 // They are created even if -XX:-UsePerfData is set and in
66 // that case, they will be allocated on C heap.
67
68 _total_threads_count =
69 PerfDataManager::create_counter(JAVA_THREADS, "started",
70 PerfData::U_Events, CHECK);
71
72 _live_threads_count =
73 PerfDataManager::create_variable(JAVA_THREADS, "live",
74 PerfData::U_None, CHECK);
75
76 _peak_threads_count =
77 PerfDataManager::create_variable(JAVA_THREADS, "livePeak",
78 PerfData::U_None, CHECK);
79
80 _daemon_threads_count =
81 PerfDataManager::create_variable(JAVA_THREADS, "daemon",
82 PerfData::U_None, CHECK);
83
84 if (os::is_thread_cpu_time_supported()) {
85 _thread_cpu_time_enabled = true;
86 }
87 }
88
89 void ThreadService::reset_peak_thread_count() {
90 // Acquire the lock to update the peak thread count
91 // to synchronize with thread addition and removal.
92 MutexLockerEx mu(Threads_lock);
93 _peak_threads_count->set_value(get_live_thread_count());
94 }
95
96 void ThreadService::add_thread(JavaThread* thread, bool daemon) {
97 // Do not count VM internal or JVMTI agent threads
98 if (thread->is_hidden_from_external_view() ||
99 thread->is_jvmti_agent_thread()) {
100 return;
101 }
102
103 _total_threads_count->inc();
104 _live_threads_count->inc();
105
106 if (_live_threads_count->get_value() > _peak_threads_count->get_value()) {
107 _peak_threads_count->set_value(_live_threads_count->get_value());
108 }
109
110 if (daemon) {
111 _daemon_threads_count->inc();
112 }
113 }
114
115 void ThreadService::remove_thread(JavaThread* thread, bool daemon) {
116 Atomic::dec((jint*) &_exiting_threads_count);
117
118 if (thread->is_hidden_from_external_view() ||
119 thread->is_jvmti_agent_thread()) {
120 return;
121 }
122
123 _live_threads_count->set_value(_live_threads_count->get_value() - 1);
124
125 if (daemon) {
126 _daemon_threads_count->set_value(_daemon_threads_count->get_value() - 1);
127 Atomic::dec((jint*) &_exiting_daemon_threads_count);
128 }
129 }
130
131 void ThreadService::current_thread_exiting(JavaThread* jt) {
132 assert(jt == JavaThread::current(), "Called by current thread");
133 Atomic::inc((jint*) &_exiting_threads_count);
134
135 oop threadObj = jt->threadObj();
136 if (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)) {
137 Atomic::inc((jint*) &_exiting_daemon_threads_count);
138 }
139 }
140
141 // FIXME: JVMTI should call this function
142 Handle ThreadService::get_current_contended_monitor(JavaThread* thread) {
143 assert(thread != NULL, "should be non-NULL");
144 assert(Threads_lock->owned_by_self(), "must grab Threads_lock or be at safepoint");
145
146 ObjectMonitor *wait_obj = thread->current_waiting_monitor();
147
148 oop obj = NULL;
149 if (wait_obj != NULL) {
150 // thread is doing an Object.wait() call
151 obj = (oop) wait_obj->object();
152 assert(obj != NULL, "Object.wait() should have an object");
153 } else {
154 ObjectMonitor *enter_obj = thread->current_pending_monitor();
155 if (enter_obj != NULL) {
156 // thread is trying to enter() or raw_enter() an ObjectMonitor.
157 obj = (oop) enter_obj->object();
158 }
159 // If obj == NULL, then ObjectMonitor is raw which doesn't count.
160 }
161
162 Handle h(obj);
163 return h;
164 }
165
166 bool ThreadService::set_thread_monitoring_contention(bool flag) {
167 MutexLocker m(Management_lock);
168
169 bool prev = _thread_monitoring_contention_enabled;
170 _thread_monitoring_contention_enabled = flag;
171
172 return prev;
173 }
174
175 bool ThreadService::set_thread_cpu_time_enabled(bool flag) {
176 MutexLocker m(Management_lock);
177
178 bool prev = _thread_cpu_time_enabled;
179 _thread_cpu_time_enabled = flag;
180
181 return prev;
182 }
183
184 // GC support
185 void ThreadService::oops_do(OopClosure* f) {
186 for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) {
187 dump->oops_do(f);
188 }
189 }
190
191 void ThreadService::add_thread_dump(ThreadDumpResult* dump) {
192 MutexLocker ml(Management_lock);
193 if (_threaddump_list == NULL) {
194 _threaddump_list = dump;
195 } else {
196 dump->set_next(_threaddump_list);
197 _threaddump_list = dump;
198 }
199 }
200
201 void ThreadService::remove_thread_dump(ThreadDumpResult* dump) {
202 MutexLocker ml(Management_lock);
203
204 ThreadDumpResult* prev = NULL;
205 bool found = false;
206 for (ThreadDumpResult* d = _threaddump_list; d != NULL; prev = d, d = d->next()) {
207 if (d == dump) {
208 if (prev == NULL) {
209 _threaddump_list = dump->next();
210 } else {
211 prev->set_next(dump->next());
212 }
213 found = true;
214 break;
215 }
216 }
217 assert(found, "The threaddump result to be removed must exist.");
218 }
219
220 // Dump stack trace of threads specified in the given threads array.
221 // Returns StackTraceElement[][] each element is the stack trace of a thread in
222 // the corresponding entry in the given threads array
223 Handle ThreadService::dump_stack_traces(GrowableArray<instanceHandle>* threads,
224 int num_threads,
225 TRAPS) {
226 assert(num_threads > 0, "just checking");
227
228 ThreadDumpResult dump_result;
229 VM_ThreadDump op(&dump_result,
230 threads,
231 num_threads,
232 -1, /* entire stack */
233 false, /* with locked monitors */
234 false /* with locked synchronizers */);
235 VMThread::execute(&op);
236
237 // Allocate the resulting StackTraceElement[][] object
238
239 ResourceMark rm(THREAD);
240 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_StackTraceElement_array(), true, CHECK_NH);
241 objArrayKlassHandle ik (THREAD, k);
242 objArrayOop r = oopFactory::new_objArray(ik(), num_threads, CHECK_NH);
243 objArrayHandle result_obj(THREAD, r);
244
245 int num_snapshots = dump_result.num_snapshots();
246 assert(num_snapshots == num_threads, "Must have num_threads thread snapshots");
247 int i = 0;
248 for (ThreadSnapshot* ts = dump_result.snapshots(); ts != NULL; i++, ts = ts->next()) {
249 ThreadStackTrace* stacktrace = ts->get_stack_trace();
250 if (stacktrace == NULL) {
251 // No stack trace
252 result_obj->obj_at_put(i, NULL);
253 } else {
254 // Construct an array of java/lang/StackTraceElement object
255 Handle backtrace_h = stacktrace->allocate_fill_stack_trace_element_array(CHECK_NH);
256 result_obj->obj_at_put(i, backtrace_h());
257 }
258 }
259
260 return result_obj;
261 }
262
263 void ThreadService::reset_contention_count_stat(JavaThread* thread) {
264 ThreadStatistics* stat = thread->get_thread_stat();
265 if (stat != NULL) {
266 stat->reset_count_stat();
267 }
268 }
269
270 void ThreadService::reset_contention_time_stat(JavaThread* thread) {
271 ThreadStatistics* stat = thread->get_thread_stat();
272 if (stat != NULL) {
273 stat->reset_time_stat();
274 }
275 }
276
277 // Find deadlocks involving object monitors and concurrent locks if concurrent_locks is true
278 DeadlockCycle* ThreadService::find_deadlocks_at_safepoint(bool concurrent_locks) {
279 // This code was modified from the original Threads::find_deadlocks code.
280 int globalDfn = 0, thisDfn;
281 ObjectMonitor* waitingToLockMonitor = NULL;
282 oop waitingToLockBlocker = NULL;
283 bool blocked_on_monitor = false;
284 JavaThread *currentThread, *previousThread;
285 int num_deadlocks = 0;
286
287 for (JavaThread* p = Threads::first(); p != NULL; p = p->next()) {
288 // Initialize the depth-first-number
289 p->set_depth_first_number(-1);
290 }
291
292 DeadlockCycle* deadlocks = NULL;
293 DeadlockCycle* last = NULL;
294 DeadlockCycle* cycle = new DeadlockCycle();
295 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
296 if (jt->depth_first_number() >= 0) {
297 // this thread was already visited
298 continue;
299 }
300
301 thisDfn = globalDfn;
302 jt->set_depth_first_number(globalDfn++);
303 previousThread = jt;
304 currentThread = jt;
305
306 cycle->reset();
307
308 // When there is a deadlock, all the monitors involved in the dependency
309 // cycle must be contended and heavyweight. So we only care about the
310 // heavyweight monitor a thread is waiting to lock.
311 waitingToLockMonitor = (ObjectMonitor*)jt->current_pending_monitor();
312 if (concurrent_locks) {
313 waitingToLockBlocker = jt->current_park_blocker();
314 }
315 while (waitingToLockMonitor != NULL || waitingToLockBlocker != NULL) {
316 cycle->add_thread(currentThread);
317 if (waitingToLockMonitor != NULL) {
318 currentThread = Threads::owning_thread_from_monitor_owner((address)waitingToLockMonitor->owner(),
319 false /* no locking needed */);
320 } else {
321 if (concurrent_locks) {
322 if (waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
323 oop threadObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
324 currentThread = threadObj != NULL ? java_lang_Thread::thread(threadObj) : NULL;
325 } else {
326 currentThread = NULL;
327 }
328 }
329 }
330
331 if (currentThread == NULL) {
332 // No dependency on another thread
333 break;
334 }
335 if (currentThread->depth_first_number() < 0) {
336 // First visit to this thread
337 currentThread->set_depth_first_number(globalDfn++);
338 } else if (currentThread->depth_first_number() < thisDfn) {
339 // Thread already visited, and not on a (new) cycle
340 break;
341 } else if (currentThread == previousThread) {
342 // Self-loop, ignore
343 break;
344 } else {
345 // We have a (new) cycle
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 previousThread = currentThread;
361 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
362 if (concurrent_locks) {
363 waitingToLockBlocker = currentThread->current_park_blocker();
364 }
365 }
366
367 }
368
369 return deadlocks;
370 }
371
372 ThreadDumpResult::ThreadDumpResult() : _num_threads(0), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL) {
373
374 // Create a new ThreadDumpResult object and append to the list.
375 // If GC happens before this function returns, methodOop
376 // in the stack trace will be visited.
377 ThreadService::add_thread_dump(this);
378 }
379
380 ThreadDumpResult::ThreadDumpResult(int num_threads) : _num_threads(num_threads), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL) {
381 // Create a new ThreadDumpResult object and append to the list.
382 // If GC happens before this function returns, oops
383 // will be visited.
384 ThreadService::add_thread_dump(this);
385 }
386
387 ThreadDumpResult::~ThreadDumpResult() {
388 ThreadService::remove_thread_dump(this);
389
390 // free all the ThreadSnapshot objects created during
391 // the VM_ThreadDump operation
392 ThreadSnapshot* ts = _snapshots;
393 while (ts != NULL) {
394 ThreadSnapshot* p = ts;
395 ts = ts->next();
396 delete p;
397 }
398 }
399
400
401 void ThreadDumpResult::add_thread_snapshot(ThreadSnapshot* ts) {
402 assert(_num_threads == 0 || _num_snapshots < _num_threads,
403 "_num_snapshots must be less than _num_threads");
404 _num_snapshots++;
405 if (_snapshots == NULL) {
406 _snapshots = ts;
407 } else {
408 _last->set_next(ts);
409 }
410 _last = ts;
411 }
412
413 void ThreadDumpResult::oops_do(OopClosure* f) {
414 for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) {
415 ts->oops_do(f);
416 }
417 }
418
419 StackFrameInfo::StackFrameInfo(javaVFrame* jvf, bool with_lock_info) {
420 _method = jvf->method();
421 _bci = jvf->bci();
422 _locked_monitors = NULL;
423 if (with_lock_info) {
424 ResourceMark rm;
425 GrowableArray<MonitorInfo*>* list = jvf->locked_monitors();
426 int length = list->length();
427 if (length > 0) {
428 _locked_monitors = new (ResourceObj::C_HEAP) GrowableArray<oop>(length, true);
429 for (int i = 0; i < length; i++) {
430 MonitorInfo* monitor = list->at(i);
431 assert(monitor->owner(), "This monitor must have an owning object");
432 _locked_monitors->append(monitor->owner());
433 }
434 }
435 }
436 }
437
438 void StackFrameInfo::oops_do(OopClosure* f) {
439 f->do_oop((oop*) &_method);
440 if (_locked_monitors != NULL) {
441 int length = _locked_monitors->length();
442 for (int i = 0; i < length; i++) {
443 f->do_oop((oop*) _locked_monitors->adr_at(i));
444 }
445 }
446 }
447
448 void StackFrameInfo::print_on(outputStream* st) const {
449 ResourceMark rm;
450 java_lang_Throwable::print_stack_element(st, method(), bci());
451 int len = (_locked_monitors != NULL ? _locked_monitors->length() : 0);
452 for (int i = 0; i < len; i++) {
453 oop o = _locked_monitors->at(i);
454 instanceKlass* ik = instanceKlass::cast(o->klass());
455 st->print_cr("\t- locked <" INTPTR_FORMAT "> (a %s)", (address)o, ik->external_name());
456 }
457
458 }
459
460 // Iterate through monitor cache to find JNI locked monitors
461 class InflatedMonitorsClosure: public MonitorClosure {
462 private:
463 ThreadStackTrace* _stack_trace;
464 Thread* _thread;
465 public:
466 InflatedMonitorsClosure(Thread* t, ThreadStackTrace* st) {
467 _thread = t;
468 _stack_trace = st;
469 }
470 void do_monitor(ObjectMonitor* mid) {
471 if (mid->owner() == _thread) {
472 oop object = (oop) mid->object();
473 if (!_stack_trace->is_owned_monitor_on_stack(object)) {
474 _stack_trace->add_jni_locked_monitor(object);
475 }
476 }
477 }
478 };
479
480 ThreadStackTrace::ThreadStackTrace(JavaThread* t, bool with_locked_monitors) {
481 _thread = t;
482 _frames = new (ResourceObj::C_HEAP) GrowableArray<StackFrameInfo*>(INITIAL_ARRAY_SIZE, true);
483 _depth = 0;
484 _with_locked_monitors = with_locked_monitors;
485 if (_with_locked_monitors) {
486 _jni_locked_monitors = new (ResourceObj::C_HEAP) GrowableArray<oop>(INITIAL_ARRAY_SIZE, true);
487 } else {
488 _jni_locked_monitors = NULL;
489 }
490 }
491
492 ThreadStackTrace::~ThreadStackTrace() {
493 for (int i = 0; i < _frames->length(); i++) {
494 delete _frames->at(i);
495 }
496 delete _frames;
497 if (_jni_locked_monitors != NULL) {
498 delete _jni_locked_monitors;
499 }
500 }
501
502 void ThreadStackTrace::dump_stack_at_safepoint(int maxDepth) {
503 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
504
505 if (_thread->has_last_Java_frame()) {
506 RegisterMap reg_map(_thread);
507 vframe* start_vf = _thread->last_java_vframe(®_map);
508 int count = 0;
509 for (vframe* f = start_vf; f; f = f->sender() ) {
510 if (f->is_java_frame()) {
511 javaVFrame* jvf = javaVFrame::cast(f);
512 add_stack_frame(jvf);
513 count++;
514 } else {
515 // Ignore non-Java frames
516 }
517 if (maxDepth > 0 && count == maxDepth) {
518 // Skip frames if more than maxDepth
519 break;
520 }
521 }
522 }
523
524 if (_with_locked_monitors) {
525 // Iterate inflated monitors and find monitors locked by this thread
526 // not found in the stack
527 InflatedMonitorsClosure imc(_thread, this);
528 ObjectSynchronizer::monitors_iterate(&imc);
529 }
530 }
531
532
533 bool ThreadStackTrace::is_owned_monitor_on_stack(oop object) {
534 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
535
536 bool found = false;
537 int num_frames = get_stack_depth();
538 for (int depth = 0; depth < num_frames; depth++) {
539 StackFrameInfo* frame = stack_frame_at(depth);
540 int len = frame->num_locked_monitors();
541 GrowableArray<oop>* locked_monitors = frame->locked_monitors();
542 for (int j = 0; j < len; j++) {
543 oop monitor = locked_monitors->at(j);
544 assert(monitor != NULL && monitor->is_instance(), "must be a Java object");
545 if (monitor == object) {
546 found = true;
547 break;
548 }
549 }
550 }
551 return found;
552 }
553
554 Handle ThreadStackTrace::allocate_fill_stack_trace_element_array(TRAPS) {
555 klassOop k = SystemDictionary::StackTraceElement_klass();
556 assert(k != NULL, "must be loaded in 1.4+");
557 instanceKlassHandle ik(THREAD, k);
558
559 // Allocate an array of java/lang/StackTraceElement object
560 objArrayOop ste = oopFactory::new_objArray(ik(), _depth, CHECK_NH);
561 objArrayHandle backtrace(THREAD, ste);
562 for (int j = 0; j < _depth; j++) {
563 StackFrameInfo* frame = _frames->at(j);
564 methodHandle mh(THREAD, frame->method());
565 oop element = java_lang_StackTraceElement::create(mh, frame->bci(), CHECK_NH);
566 backtrace->obj_at_put(j, element);
567 }
568 return backtrace;
569 }
570
571 void ThreadStackTrace::add_stack_frame(javaVFrame* jvf) {
572 StackFrameInfo* frame = new StackFrameInfo(jvf, _with_locked_monitors);
573 _frames->append(frame);
574 _depth++;
575 }
576
577 void ThreadStackTrace::oops_do(OopClosure* f) {
578 int length = _frames->length();
579 for (int i = 0; i < length; i++) {
580 _frames->at(i)->oops_do(f);
581 }
582
583 length = (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0);
584 for (int j = 0; j < length; j++) {
585 f->do_oop((oop*) _jni_locked_monitors->adr_at(j));
586 }
587 }
588
589 ConcurrentLocksDump::~ConcurrentLocksDump() {
590 if (_retain_map_on_free) {
591 return;
592 }
593
594 for (ThreadConcurrentLocks* t = _map; t != NULL;) {
595 ThreadConcurrentLocks* tcl = t;
596 t = t->next();
597 delete tcl;
598 }
599 }
600
601 void ConcurrentLocksDump::dump_at_safepoint() {
602 // dump all locked concurrent locks
603 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
604
605 if (JDK_Version::is_gte_jdk16x_version()) {
606 ResourceMark rm;
607
608 GrowableArray<oop>* aos_objects = new GrowableArray<oop>(INITIAL_ARRAY_SIZE);
609
610 // Find all instances of AbstractOwnableSynchronizer
611 HeapInspection::find_instances_at_safepoint(SystemDictionary::abstract_ownable_synchronizer_klass(),
612 aos_objects);
613 // Build a map of thread to its owned AQS locks
614 build_map(aos_objects);
615 }
616 }
617
618
619 // build a map of JavaThread to all its owned AbstractOwnableSynchronizer
620 void ConcurrentLocksDump::build_map(GrowableArray<oop>* aos_objects) {
621 int length = aos_objects->length();
622 for (int i = 0; i < length; i++) {
623 oop o = aos_objects->at(i);
624 oop owner_thread_obj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(o);
625 if (owner_thread_obj != NULL) {
626 JavaThread* thread = java_lang_Thread::thread(owner_thread_obj);
627 assert(o->is_instance(), "Must be an instanceOop");
628 add_lock(thread, (instanceOop) o);
629 }
630 }
631 }
632
633 void ConcurrentLocksDump::add_lock(JavaThread* thread, instanceOop o) {
634 ThreadConcurrentLocks* tcl = thread_concurrent_locks(thread);
635 if (tcl != NULL) {
636 tcl->add_lock(o);
637 return;
638 }
639
640 // First owned lock found for this thread
641 tcl = new ThreadConcurrentLocks(thread);
642 tcl->add_lock(o);
643 if (_map == NULL) {
644 _map = tcl;
645 } else {
646 _last->set_next(tcl);
647 }
648 _last = tcl;
649 }
650
651 ThreadConcurrentLocks* ConcurrentLocksDump::thread_concurrent_locks(JavaThread* thread) {
652 for (ThreadConcurrentLocks* tcl = _map; tcl != NULL; tcl = tcl->next()) {
653 if (tcl->java_thread() == thread) {
654 return tcl;
655 }
656 }
657 return NULL;
658 }
659
660 void ConcurrentLocksDump::print_locks_on(JavaThread* t, outputStream* st) {
661 st->print_cr(" Locked ownable synchronizers:");
662 ThreadConcurrentLocks* tcl = thread_concurrent_locks(t);
663 GrowableArray<instanceOop>* locks = (tcl != NULL ? tcl->owned_locks() : NULL);
664 if (locks == NULL || locks->is_empty()) {
665 st->print_cr("\t- None");
666 st->cr();
667 return;
668 }
669
670 for (int i = 0; i < locks->length(); i++) {
671 instanceOop obj = locks->at(i);
672 instanceKlass* ik = instanceKlass::cast(obj->klass());
673 st->print_cr("\t- <" INTPTR_FORMAT "> (a %s)", (address)obj, ik->external_name());
674 }
675 st->cr();
676 }
677
678 ThreadConcurrentLocks::ThreadConcurrentLocks(JavaThread* thread) {
679 _thread = thread;
680 _owned_locks = new (ResourceObj::C_HEAP) GrowableArray<instanceOop>(INITIAL_ARRAY_SIZE, true);
681 _next = NULL;
682 }
683
684 ThreadConcurrentLocks::~ThreadConcurrentLocks() {
685 delete _owned_locks;
686 }
687
688 void ThreadConcurrentLocks::add_lock(instanceOop o) {
689 _owned_locks->append(o);
690 }
691
692 void ThreadConcurrentLocks::oops_do(OopClosure* f) {
693 int length = _owned_locks->length();
694 for (int i = 0; i < length; i++) {
695 f->do_oop((oop*) _owned_locks->adr_at(i));
696 }
697 }
698
699 ThreadStatistics::ThreadStatistics() {
700 _contended_enter_count = 0;
701 _monitor_wait_count = 0;
702 _sleep_count = 0;
703 _count_pending_reset = false;
704 _timer_pending_reset = false;
705 memset((void*) _perf_recursion_counts, 0, sizeof(_perf_recursion_counts));
706 }
707
708 ThreadSnapshot::ThreadSnapshot(JavaThread* thread) {
709 _thread = thread;
710 _threadObj = thread->threadObj();
711 _stack_trace = NULL;
712 _concurrent_locks = NULL;
713 _next = NULL;
714
715 ThreadStatistics* stat = thread->get_thread_stat();
716 _contended_enter_ticks = stat->contended_enter_ticks();
717 _contended_enter_count = stat->contended_enter_count();
718 _monitor_wait_ticks = stat->monitor_wait_ticks();
719 _monitor_wait_count = stat->monitor_wait_count();
720 _sleep_ticks = stat->sleep_ticks();
721 _sleep_count = stat->sleep_count();
722
723 _blocker_object = NULL;
724 _blocker_object_owner = NULL;
725
726 _thread_status = java_lang_Thread::get_thread_status(_threadObj);
727 _is_ext_suspended = thread->is_being_ext_suspended();
728 _is_in_native = (thread->thread_state() == _thread_in_native);
729
730 if (_thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER ||
731 _thread_status == java_lang_Thread::IN_OBJECT_WAIT ||
732 _thread_status == java_lang_Thread::IN_OBJECT_WAIT_TIMED) {
733
734 Handle obj = ThreadService::get_current_contended_monitor(thread);
735 if (obj() == NULL) {
736 // monitor no longer exists; thread is not blocked
737 _thread_status = java_lang_Thread::RUNNABLE;
738 } else {
739 _blocker_object = obj();
740 JavaThread* owner = ObjectSynchronizer::get_lock_owner(obj, false);
741 if ((owner == NULL && _thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER)
742 || (owner != NULL && owner->is_attaching())) {
743 // ownership information of the monitor is not available
744 // (may no longer be owned or releasing to some other thread)
745 // make this thread in RUNNABLE state.
746 // And when the owner thread is in attaching state, the java thread
747 // is not completely initialized. For example thread name and id
748 // and may not be set, so hide the attaching thread.
749 _thread_status = java_lang_Thread::RUNNABLE;
750 _blocker_object = NULL;
751 } else if (owner != NULL) {
752 _blocker_object_owner = owner->threadObj();
753 }
754 }
755 }
756
757 // Support for JSR-166 locks
758 if (JDK_Version::current().supports_thread_park_blocker() &&
759 (_thread_status == java_lang_Thread::PARKED ||
760 _thread_status == java_lang_Thread::PARKED_TIMED)) {
761
762 _blocker_object = thread->current_park_blocker();
763 if (_blocker_object != NULL && _blocker_object->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
764 _blocker_object_owner = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(_blocker_object);
765 }
766 }
767 }
768
769 ThreadSnapshot::~ThreadSnapshot() {
770 delete _stack_trace;
771 delete _concurrent_locks;
772 }
773
774 void ThreadSnapshot::dump_stack_at_safepoint(int max_depth, bool with_locked_monitors) {
775 _stack_trace = new ThreadStackTrace(_thread, with_locked_monitors);
776 _stack_trace->dump_stack_at_safepoint(max_depth);
777 }
778
779
780 void ThreadSnapshot::oops_do(OopClosure* f) {
781 f->do_oop(&_threadObj);
782 f->do_oop(&_blocker_object);
783 f->do_oop(&_blocker_object_owner);
784 if (_stack_trace != NULL) {
785 _stack_trace->oops_do(f);
786 }
787 if (_concurrent_locks != NULL) {
788 _concurrent_locks->oops_do(f);
789 }
790 }
791
792 DeadlockCycle::DeadlockCycle() {
793 _is_deadlock = false;
794 _threads = new (ResourceObj::C_HEAP) GrowableArray<JavaThread*>(INITIAL_ARRAY_SIZE, true);
795 _next = NULL;
796 }
797
798 DeadlockCycle::~DeadlockCycle() {
799 delete _threads;
800 }
801
802 void DeadlockCycle::print_on(outputStream* st) const {
803 st->cr();
804 st->print_cr("Found one Java-level deadlock:");
805 st->print("=============================");
806
807 JavaThread* currentThread;
808 ObjectMonitor* waitingToLockMonitor;
809 oop waitingToLockBlocker;
810 int len = _threads->length();
811 for (int i = 0; i < len; i++) {
812 currentThread = _threads->at(i);
813 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
814 waitingToLockBlocker = currentThread->current_park_blocker();
815 st->cr();
816 st->print_cr("\"%s\":", currentThread->get_thread_name());
817 const char* owner_desc = ",\n which is held by";
818 if (waitingToLockMonitor != NULL) {
819 st->print(" waiting to lock monitor " INTPTR_FORMAT, waitingToLockMonitor);
820 oop obj = (oop)waitingToLockMonitor->object();
821 if (obj != NULL) {
822 st->print(" (object "INTPTR_FORMAT ", a %s)", (address)obj,
823 (instanceKlass::cast(obj->klass()))->external_name());
824
825 if (!currentThread->current_pending_monitor_is_from_java()) {
826 owner_desc = "\n in JNI, which is held by";
827 }
828 } else {
829 // No Java object associated - a JVMTI raw monitor
830 owner_desc = " (JVMTI raw monitor),\n which is held by";
831 }
832 currentThread = Threads::owning_thread_from_monitor_owner(
833 (address)waitingToLockMonitor->owner(), false /* no locking needed */);
834 } else {
835 st->print(" waiting for ownable synchronizer " INTPTR_FORMAT ", (a %s)",
836 (address)waitingToLockBlocker,
837 (instanceKlass::cast(waitingToLockBlocker->klass()))->external_name());
838 assert(waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass()),
839 "Must be an AbstractOwnableSynchronizer");
840 oop ownerObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
841 currentThread = java_lang_Thread::thread(ownerObj);
842 }
843 st->print("%s \"%s\"", owner_desc, currentThread->get_thread_name());
844 }
845
846 st->cr();
847 st->cr();
848
849 // Print stack traces
850 bool oldJavaMonitorsInStackTrace = JavaMonitorsInStackTrace;
851 JavaMonitorsInStackTrace = true;
852 st->print_cr("Java stack information for the threads listed above:");
853 st->print_cr("===================================================");
854 for (int j = 0; j < len; j++) {
855 currentThread = _threads->at(j);
856 st->print_cr("\"%s\":", currentThread->get_thread_name());
857 currentThread->print_stack_on(st);
858 }
859 JavaMonitorsInStackTrace = oldJavaMonitorsInStackTrace;
860 }
861
862 ThreadsListEnumerator::ThreadsListEnumerator(Thread* cur_thread,
863 bool include_jvmti_agent_threads,
864 bool include_jni_attaching_threads) {
865 assert(cur_thread == Thread::current(), "Check current thread");
866
867 int init_size = ThreadService::get_live_thread_count();
868 _threads_array = new GrowableArray<instanceHandle>(init_size);
869
870 MutexLockerEx ml(Threads_lock);
871
872 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
873 // skips JavaThreads in the process of exiting
874 // and also skips VM internal JavaThreads
875 // Threads in _thread_new or _thread_new_trans state are included.
876 // i.e. threads have been started but not yet running.
877 if (jt->threadObj() == NULL ||
878 jt->is_exiting() ||
879 !java_lang_Thread::is_alive(jt->threadObj()) ||
880 jt->is_hidden_from_external_view()) {
881 continue;
882 }
883
884 // skip agent threads
885 if (!include_jvmti_agent_threads && jt->is_jvmti_agent_thread()) {
886 continue;
887 }
888
889 // skip jni threads in the process of attaching
890 if (!include_jni_attaching_threads && jt->is_attaching()) {
891 continue;
892 }
893
894 instanceHandle h(cur_thread, (instanceOop) jt->threadObj());
895 _threads_array->append(h);
896 }
897 }