1 /*
2 * Copyright (c) 2003, 2012, 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::add_thread_dump(ThreadDumpResult* dump) {
204 MutexLocker ml(Management_lock);
205 if (_threaddump_list == NULL) {
206 _threaddump_list = dump;
207 } else {
208 dump->set_next(_threaddump_list);
209 _threaddump_list = dump;
210 }
211 }
212
213 void ThreadService::remove_thread_dump(ThreadDumpResult* dump) {
214 MutexLocker ml(Management_lock);
215
216 ThreadDumpResult* prev = NULL;
217 bool found = false;
218 for (ThreadDumpResult* d = _threaddump_list; d != NULL; prev = d, d = d->next()) {
219 if (d == dump) {
220 if (prev == NULL) {
221 _threaddump_list = dump->next();
222 } else {
223 prev->set_next(dump->next());
224 }
225 found = true;
226 break;
227 }
228 }
229 assert(found, "The threaddump result to be removed must exist.");
230 }
231
232 // Dump stack trace of threads specified in the given threads array.
233 // Returns StackTraceElement[][] each element is the stack trace of a thread in
234 // the corresponding entry in the given threads array
235 Handle ThreadService::dump_stack_traces(GrowableArray<instanceHandle>* threads,
236 int num_threads,
237 TRAPS) {
238 assert(num_threads > 0, "just checking");
239
240 ThreadDumpResult dump_result;
241 VM_ThreadDump op(&dump_result,
242 threads,
243 num_threads,
244 -1, /* entire stack */
245 false, /* with locked monitors */
246 false /* with locked synchronizers */);
247 VMThread::execute(&op);
248
249 // Allocate the resulting StackTraceElement[][] object
250
251 ResourceMark rm(THREAD);
252 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_StackTraceElement_array(), true, CHECK_NH);
253 ObjArrayKlass* ik = ObjArrayKlass::cast(k);
254 objArrayOop r = oopFactory::new_objArray(ik, num_threads, CHECK_NH);
255 objArrayHandle result_obj(THREAD, r);
256
257 int num_snapshots = dump_result.num_snapshots();
258 assert(num_snapshots == num_threads, "Must have num_threads thread snapshots");
259 int i = 0;
260 for (ThreadSnapshot* ts = dump_result.snapshots(); ts != NULL; i++, ts = ts->next()) {
261 ThreadStackTrace* stacktrace = ts->get_stack_trace();
262 if (stacktrace == NULL) {
263 // No stack trace
264 result_obj->obj_at_put(i, NULL);
265 } else {
266 // Construct an array of java/lang/StackTraceElement object
267 Handle backtrace_h = stacktrace->allocate_fill_stack_trace_element_array(CHECK_NH);
268 result_obj->obj_at_put(i, backtrace_h());
269 }
270 }
271
272 return result_obj;
273 }
274
275 void ThreadService::reset_contention_count_stat(JavaThread* thread) {
276 ThreadStatistics* stat = thread->get_thread_stat();
277 if (stat != NULL) {
278 stat->reset_count_stat();
279 }
280 }
281
282 void ThreadService::reset_contention_time_stat(JavaThread* thread) {
283 ThreadStatistics* stat = thread->get_thread_stat();
284 if (stat != NULL) {
285 stat->reset_time_stat();
286 }
287 }
288
289 // Find deadlocks involving object monitors and concurrent locks if concurrent_locks is true
290 DeadlockCycle* ThreadService::find_deadlocks_at_safepoint(bool concurrent_locks) {
291 // This code was modified from the original Threads::find_deadlocks code.
292 int globalDfn = 0, thisDfn;
293 ObjectMonitor* waitingToLockMonitor = NULL;
294 oop waitingToLockBlocker = NULL;
295 bool blocked_on_monitor = false;
296 JavaThread *currentThread, *previousThread;
297 int num_deadlocks = 0;
298
299 for (JavaThread* p = Threads::first(); p != NULL; p = p->next()) {
300 // Initialize the depth-first-number
301 p->set_depth_first_number(-1);
302 }
303
304 DeadlockCycle* deadlocks = NULL;
305 DeadlockCycle* last = NULL;
306 DeadlockCycle* cycle = new DeadlockCycle();
307 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
308 if (jt->depth_first_number() >= 0) {
309 // this thread was already visited
310 continue;
311 }
312
313 thisDfn = globalDfn;
314 jt->set_depth_first_number(globalDfn++);
315 previousThread = jt;
316 currentThread = jt;
317
318 cycle->reset();
319
320 // When there is a deadlock, all the monitors involved in the dependency
321 // cycle must be contended and heavyweight. So we only care about the
322 // heavyweight monitor a thread is waiting to lock.
323 waitingToLockMonitor = (ObjectMonitor*)jt->current_pending_monitor();
324 if (concurrent_locks) {
325 waitingToLockBlocker = jt->current_park_blocker();
326 }
327 while (waitingToLockMonitor != NULL || waitingToLockBlocker != NULL) {
328 cycle->add_thread(currentThread);
329 if (waitingToLockMonitor != NULL) {
330 currentThread = Threads::owning_thread_from_monitor_owner((address)waitingToLockMonitor->owner(),
331 false /* no locking needed */);
332 } else {
333 if (concurrent_locks) {
334 if (waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
335 oop threadObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
336 currentThread = threadObj != NULL ? java_lang_Thread::thread(threadObj) : NULL;
337 } else {
338 currentThread = NULL;
339 }
340 }
341 }
342
343 if (currentThread == NULL) {
344 // No dependency on another thread
345 break;
346 }
347 if (currentThread->depth_first_number() < 0) {
348 // First visit to this thread
349 currentThread->set_depth_first_number(globalDfn++);
350 } else if (currentThread->depth_first_number() < thisDfn) {
351 // Thread already visited, and not on a (new) cycle
352 break;
353 } else if (currentThread == previousThread) {
354 // Self-loop, ignore
355 break;
356 } else {
357 // We have a (new) cycle
358 num_deadlocks++;
359
360 cycle->set_deadlock(true);
361
362 // add this cycle to the deadlocks list
363 if (deadlocks == NULL) {
364 deadlocks = cycle;
365 } else {
366 last->set_next(cycle);
367 }
368 last = cycle;
369 cycle = new DeadlockCycle();
370 break;
371 }
372 previousThread = currentThread;
373 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
374 if (concurrent_locks) {
375 waitingToLockBlocker = currentThread->current_park_blocker();
376 }
377 }
378
379 }
380 delete cycle;
381 return deadlocks;
382 }
383
384 ThreadDumpResult::ThreadDumpResult() : _num_threads(0), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL) {
385
386 // Create a new ThreadDumpResult object and append to the list.
387 // If GC happens before this function returns, Method*
388 // in the stack trace will be visited.
389 ThreadService::add_thread_dump(this);
390 }
391
392 ThreadDumpResult::ThreadDumpResult(int num_threads) : _num_threads(num_threads), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL) {
393 // Create a new ThreadDumpResult object and append to the list.
394 // If GC happens before this function returns, oops
395 // will be visited.
396 ThreadService::add_thread_dump(this);
397 }
398
399 ThreadDumpResult::~ThreadDumpResult() {
400 ThreadService::remove_thread_dump(this);
401
402 // free all the ThreadSnapshot objects created during
403 // the VM_ThreadDump operation
404 ThreadSnapshot* ts = _snapshots;
405 while (ts != NULL) {
406 ThreadSnapshot* p = ts;
407 ts = ts->next();
408 delete p;
409 }
410 }
411
412
413 void ThreadDumpResult::add_thread_snapshot(ThreadSnapshot* ts) {
414 assert(_num_threads == 0 || _num_snapshots < _num_threads,
415 "_num_snapshots must be less than _num_threads");
416 _num_snapshots++;
417 if (_snapshots == NULL) {
418 _snapshots = ts;
419 } else {
420 _last->set_next(ts);
421 }
422 _last = ts;
423 }
424
425 void ThreadDumpResult::oops_do(OopClosure* f) {
426 for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) {
427 ts->oops_do(f);
428 }
429 }
430
431 StackFrameInfo::StackFrameInfo(javaVFrame* jvf, bool with_lock_info) {
432 _method = jvf->method();
433 _bci = jvf->bci();
434 _locked_monitors = NULL;
435 if (with_lock_info) {
436 ResourceMark rm;
437 GrowableArray<MonitorInfo*>* list = jvf->locked_monitors();
438 int length = list->length();
439 if (length > 0) {
440 _locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(length, true);
441 for (int i = 0; i < length; i++) {
442 MonitorInfo* monitor = list->at(i);
443 assert(monitor->owner(), "This monitor must have an owning object");
444 _locked_monitors->append(monitor->owner());
445 }
446 }
447 }
448 }
449
450 void StackFrameInfo::oops_do(OopClosure* f) {
451 if (_locked_monitors != NULL) {
452 int length = _locked_monitors->length();
453 for (int i = 0; i < length; i++) {
454 f->do_oop((oop*) _locked_monitors->adr_at(i));
455 }
456 }
457 }
458
459 void StackFrameInfo::print_on(outputStream* st) const {
460 ResourceMark rm;
461 java_lang_Throwable::print_stack_element(st, method(), bci());
462 int len = (_locked_monitors != NULL ? _locked_monitors->length() : 0);
463 for (int i = 0; i < len; i++) {
464 oop o = _locked_monitors->at(i);
465 InstanceKlass* ik = InstanceKlass::cast(o->klass());
466 st->print_cr("\t- locked <" INTPTR_FORMAT "> (a %s)", (address)o, ik->external_name());
467 }
468
469 }
470
471 // Iterate through monitor cache to find JNI locked monitors
472 class InflatedMonitorsClosure: public MonitorClosure {
473 private:
474 ThreadStackTrace* _stack_trace;
475 Thread* _thread;
476 public:
477 InflatedMonitorsClosure(Thread* t, ThreadStackTrace* st) {
478 _thread = t;
479 _stack_trace = st;
480 }
481 void do_monitor(ObjectMonitor* mid) {
482 if (mid->owner() == _thread) {
483 oop object = (oop) mid->object();
484 if (!_stack_trace->is_owned_monitor_on_stack(object)) {
485 _stack_trace->add_jni_locked_monitor(object);
486 }
487 }
488 }
489 };
490
491 ThreadStackTrace::ThreadStackTrace(JavaThread* t, bool with_locked_monitors) {
492 _thread = t;
493 _frames = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<StackFrameInfo*>(INITIAL_ARRAY_SIZE, true);
494 _depth = 0;
495 _with_locked_monitors = with_locked_monitors;
496 if (_with_locked_monitors) {
497 _jni_locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(INITIAL_ARRAY_SIZE, true);
498 } else {
499 _jni_locked_monitors = NULL;
500 }
501 }
502
503 ThreadStackTrace::~ThreadStackTrace() {
504 for (int i = 0; i < _frames->length(); i++) {
505 delete _frames->at(i);
506 }
507 delete _frames;
508 if (_jni_locked_monitors != NULL) {
509 delete _jni_locked_monitors;
510 }
511 }
512
513 void ThreadStackTrace::dump_stack_at_safepoint(int maxDepth) {
514 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
515
516 if (_thread->has_last_Java_frame()) {
517 RegisterMap reg_map(_thread);
518 vframe* start_vf = _thread->last_java_vframe(®_map);
519 int count = 0;
520 for (vframe* f = start_vf; f; f = f->sender() ) {
521 if (f->is_java_frame()) {
522 javaVFrame* jvf = javaVFrame::cast(f);
523 add_stack_frame(jvf);
524 count++;
525 } else {
526 // Ignore non-Java frames
527 }
528 if (maxDepth > 0 && count == maxDepth) {
529 // Skip frames if more than maxDepth
530 break;
531 }
532 }
533 }
534
535 if (_with_locked_monitors) {
536 // Iterate inflated monitors and find monitors locked by this thread
537 // not found in the stack
538 InflatedMonitorsClosure imc(_thread, this);
539 ObjectSynchronizer::monitors_iterate(&imc);
540 }
541 }
542
543
544 bool ThreadStackTrace::is_owned_monitor_on_stack(oop object) {
545 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
546
547 bool found = false;
548 int num_frames = get_stack_depth();
549 for (int depth = 0; depth < num_frames; depth++) {
550 StackFrameInfo* frame = stack_frame_at(depth);
551 int len = frame->num_locked_monitors();
552 GrowableArray<oop>* locked_monitors = frame->locked_monitors();
553 for (int j = 0; j < len; j++) {
554 oop monitor = locked_monitors->at(j);
555 assert(monitor != NULL && monitor->is_instance(), "must be a Java object");
556 if (monitor == object) {
557 found = true;
558 break;
559 }
560 }
561 }
562 return found;
563 }
564
565 Handle ThreadStackTrace::allocate_fill_stack_trace_element_array(TRAPS) {
566 Klass* k = SystemDictionary::StackTraceElement_klass();
567 assert(k != NULL, "must be loaded in 1.4+");
568 instanceKlassHandle ik(THREAD, k);
569
570 // Allocate an array of java/lang/StackTraceElement object
571 objArrayOop ste = oopFactory::new_objArray(ik(), _depth, CHECK_NH);
572 objArrayHandle backtrace(THREAD, ste);
573 for (int j = 0; j < _depth; j++) {
574 StackFrameInfo* frame = _frames->at(j);
575 methodHandle mh(THREAD, frame->method());
576 oop element = java_lang_StackTraceElement::create(mh, frame->bci(), CHECK_NH);
577 backtrace->obj_at_put(j, element);
578 }
579 return backtrace;
580 }
581
582 void ThreadStackTrace::add_stack_frame(javaVFrame* jvf) {
583 StackFrameInfo* frame = new StackFrameInfo(jvf, _with_locked_monitors);
584 _frames->append(frame);
585 _depth++;
586 }
587
588 void ThreadStackTrace::oops_do(OopClosure* f) {
589 int length = _frames->length();
590 for (int i = 0; i < length; i++) {
591 _frames->at(i)->oops_do(f);
592 }
593
594 length = (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0);
595 for (int j = 0; j < length; j++) {
596 f->do_oop((oop*) _jni_locked_monitors->adr_at(j));
597 }
598 }
599
600 ConcurrentLocksDump::~ConcurrentLocksDump() {
601 if (_retain_map_on_free) {
602 return;
603 }
604
605 for (ThreadConcurrentLocks* t = _map; t != NULL;) {
606 ThreadConcurrentLocks* tcl = t;
607 t = t->next();
608 delete tcl;
609 }
610 }
611
612 void ConcurrentLocksDump::dump_at_safepoint() {
613 // dump all locked concurrent locks
614 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
615
616 if (JDK_Version::is_gte_jdk16x_version()) {
617 ResourceMark rm;
618
619 GrowableArray<oop>* aos_objects = new GrowableArray<oop>(INITIAL_ARRAY_SIZE);
620
621 // Find all instances of AbstractOwnableSynchronizer
622 HeapInspection::find_instances_at_safepoint(SystemDictionary::abstract_ownable_synchronizer_klass(),
623 aos_objects);
624 // Build a map of thread to its owned AQS locks
625 build_map(aos_objects);
626 }
627 }
628
629
630 // build a map of JavaThread to all its owned AbstractOwnableSynchronizer
631 void ConcurrentLocksDump::build_map(GrowableArray<oop>* aos_objects) {
632 int length = aos_objects->length();
633 for (int i = 0; i < length; i++) {
634 oop o = aos_objects->at(i);
635 oop owner_thread_obj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(o);
636 if (owner_thread_obj != NULL) {
637 JavaThread* thread = java_lang_Thread::thread(owner_thread_obj);
638 assert(o->is_instance(), "Must be an instanceOop");
639 add_lock(thread, (instanceOop) o);
640 }
641 }
642 }
643
644 void ConcurrentLocksDump::add_lock(JavaThread* thread, instanceOop o) {
645 ThreadConcurrentLocks* tcl = thread_concurrent_locks(thread);
646 if (tcl != NULL) {
647 tcl->add_lock(o);
648 return;
649 }
650
651 // First owned lock found for this thread
652 tcl = new ThreadConcurrentLocks(thread);
653 tcl->add_lock(o);
654 if (_map == NULL) {
655 _map = tcl;
656 } else {
657 _last->set_next(tcl);
658 }
659 _last = tcl;
660 }
661
662 ThreadConcurrentLocks* ConcurrentLocksDump::thread_concurrent_locks(JavaThread* thread) {
663 for (ThreadConcurrentLocks* tcl = _map; tcl != NULL; tcl = tcl->next()) {
664 if (tcl->java_thread() == thread) {
665 return tcl;
666 }
667 }
668 return NULL;
669 }
670
671 void ConcurrentLocksDump::print_locks_on(JavaThread* t, outputStream* st) {
672 st->print_cr(" Locked ownable synchronizers:");
673 ThreadConcurrentLocks* tcl = thread_concurrent_locks(t);
674 GrowableArray<instanceOop>* locks = (tcl != NULL ? tcl->owned_locks() : NULL);
675 if (locks == NULL || locks->is_empty()) {
676 st->print_cr("\t- None");
677 st->cr();
678 return;
679 }
680
681 for (int i = 0; i < locks->length(); i++) {
682 instanceOop obj = locks->at(i);
683 InstanceKlass* ik = InstanceKlass::cast(obj->klass());
684 st->print_cr("\t- <" INTPTR_FORMAT "> (a %s)", (address)obj, ik->external_name());
685 }
686 st->cr();
687 }
688
689 ThreadConcurrentLocks::ThreadConcurrentLocks(JavaThread* thread) {
690 _thread = thread;
691 _owned_locks = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<instanceOop>(INITIAL_ARRAY_SIZE, true);
692 _next = NULL;
693 }
694
695 ThreadConcurrentLocks::~ThreadConcurrentLocks() {
696 delete _owned_locks;
697 }
698
699 void ThreadConcurrentLocks::add_lock(instanceOop o) {
700 _owned_locks->append(o);
701 }
702
703 void ThreadConcurrentLocks::oops_do(OopClosure* f) {
704 int length = _owned_locks->length();
705 for (int i = 0; i < length; i++) {
706 f->do_oop((oop*) _owned_locks->adr_at(i));
707 }
708 }
709
710 ThreadStatistics::ThreadStatistics() {
711 _contended_enter_count = 0;
712 _monitor_wait_count = 0;
713 _sleep_count = 0;
714 _count_pending_reset = false;
715 _timer_pending_reset = false;
716 memset((void*) _perf_recursion_counts, 0, sizeof(_perf_recursion_counts));
717 }
718
719 ThreadSnapshot::ThreadSnapshot(JavaThread* thread) {
720 _thread = thread;
721 _threadObj = thread->threadObj();
722 _stack_trace = NULL;
723 _concurrent_locks = NULL;
724 _next = NULL;
725
726 ThreadStatistics* stat = thread->get_thread_stat();
727 _contended_enter_ticks = stat->contended_enter_ticks();
728 _contended_enter_count = stat->contended_enter_count();
729 _monitor_wait_ticks = stat->monitor_wait_ticks();
730 _monitor_wait_count = stat->monitor_wait_count();
731 _sleep_ticks = stat->sleep_ticks();
732 _sleep_count = stat->sleep_count();
733
734 _blocker_object = NULL;
735 _blocker_object_owner = NULL;
736
737 _thread_status = java_lang_Thread::get_thread_status(_threadObj);
738 _is_ext_suspended = thread->is_being_ext_suspended();
739 _is_in_native = (thread->thread_state() == _thread_in_native);
740
741 if (_thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER ||
742 _thread_status == java_lang_Thread::IN_OBJECT_WAIT ||
743 _thread_status == java_lang_Thread::IN_OBJECT_WAIT_TIMED) {
744
745 Handle obj = ThreadService::get_current_contended_monitor(thread);
746 if (obj() == NULL) {
747 // monitor no longer exists; thread is not blocked
748 _thread_status = java_lang_Thread::RUNNABLE;
749 } else {
750 _blocker_object = obj();
751 JavaThread* owner = ObjectSynchronizer::get_lock_owner(obj, false);
752 if ((owner == NULL && _thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER)
753 || (owner != NULL && owner->is_attaching_via_jni())) {
754 // ownership information of the monitor is not available
755 // (may no longer be owned or releasing to some other thread)
756 // make this thread in RUNNABLE state.
757 // And when the owner thread is in attaching state, the java thread
758 // is not completely initialized. For example thread name and id
759 // and may not be set, so hide the attaching thread.
760 _thread_status = java_lang_Thread::RUNNABLE;
761 _blocker_object = NULL;
762 } else if (owner != NULL) {
763 _blocker_object_owner = owner->threadObj();
764 }
765 }
766 }
767
768 // Support for JSR-166 locks
769 if (JDK_Version::current().supports_thread_park_blocker() &&
770 (_thread_status == java_lang_Thread::PARKED ||
771 _thread_status == java_lang_Thread::PARKED_TIMED)) {
772
773 _blocker_object = thread->current_park_blocker();
774 if (_blocker_object != NULL && _blocker_object->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
775 _blocker_object_owner = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(_blocker_object);
776 }
777 }
778 }
779
780 ThreadSnapshot::~ThreadSnapshot() {
781 delete _stack_trace;
782 delete _concurrent_locks;
783 }
784
785 void ThreadSnapshot::dump_stack_at_safepoint(int max_depth, bool with_locked_monitors) {
786 _stack_trace = new ThreadStackTrace(_thread, with_locked_monitors);
787 _stack_trace->dump_stack_at_safepoint(max_depth);
788 }
789
790
791 void ThreadSnapshot::oops_do(OopClosure* f) {
792 f->do_oop(&_threadObj);
793 f->do_oop(&_blocker_object);
794 f->do_oop(&_blocker_object_owner);
795 if (_stack_trace != NULL) {
796 _stack_trace->oops_do(f);
797 }
798 if (_concurrent_locks != NULL) {
799 _concurrent_locks->oops_do(f);
800 }
801 }
802
803 DeadlockCycle::DeadlockCycle() {
804 _is_deadlock = false;
805 _threads = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<JavaThread*>(INITIAL_ARRAY_SIZE, true);
806 _next = NULL;
807 }
808
809 DeadlockCycle::~DeadlockCycle() {
810 delete _threads;
811 }
812
813 void DeadlockCycle::print_on(outputStream* st) const {
814 st->cr();
815 st->print_cr("Found one Java-level deadlock:");
816 st->print("=============================");
817
818 JavaThread* currentThread;
819 ObjectMonitor* waitingToLockMonitor;
820 oop waitingToLockBlocker;
821 int len = _threads->length();
822 for (int i = 0; i < len; i++) {
823 currentThread = _threads->at(i);
824 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
825 waitingToLockBlocker = currentThread->current_park_blocker();
826 st->cr();
827 st->print_cr("\"%s\":", currentThread->get_thread_name());
828 const char* owner_desc = ",\n which is held by";
829 if (waitingToLockMonitor != NULL) {
830 st->print(" waiting to lock monitor " INTPTR_FORMAT, waitingToLockMonitor);
831 oop obj = (oop)waitingToLockMonitor->object();
832 if (obj != NULL) {
833 st->print(" (object "INTPTR_FORMAT ", a %s)", (address)obj,
834 (InstanceKlass::cast(obj->klass()))->external_name());
835
836 if (!currentThread->current_pending_monitor_is_from_java()) {
837 owner_desc = "\n in JNI, which is held by";
838 }
839 } else {
840 // No Java object associated - a JVMTI raw monitor
841 owner_desc = " (JVMTI raw monitor),\n which is held by";
842 }
843 currentThread = Threads::owning_thread_from_monitor_owner(
844 (address)waitingToLockMonitor->owner(), false /* no locking needed */);
845 } else {
846 st->print(" waiting for ownable synchronizer " INTPTR_FORMAT ", (a %s)",
847 (address)waitingToLockBlocker,
848 (InstanceKlass::cast(waitingToLockBlocker->klass()))->external_name());
849 assert(waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass()),
850 "Must be an AbstractOwnableSynchronizer");
851 oop ownerObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
852 currentThread = java_lang_Thread::thread(ownerObj);
853 }
854 st->print("%s \"%s\"", owner_desc, currentThread->get_thread_name());
855 }
856
857 st->cr();
858 st->cr();
859
860 // Print stack traces
861 bool oldJavaMonitorsInStackTrace = JavaMonitorsInStackTrace;
862 JavaMonitorsInStackTrace = true;
863 st->print_cr("Java stack information for the threads listed above:");
864 st->print_cr("===================================================");
865 for (int j = 0; j < len; j++) {
866 currentThread = _threads->at(j);
867 st->print_cr("\"%s\":", currentThread->get_thread_name());
868 currentThread->print_stack_on(st);
869 }
870 JavaMonitorsInStackTrace = oldJavaMonitorsInStackTrace;
871 }
872
873 ThreadsListEnumerator::ThreadsListEnumerator(Thread* cur_thread,
874 bool include_jvmti_agent_threads,
875 bool include_jni_attaching_threads) {
876 assert(cur_thread == Thread::current(), "Check current thread");
877
878 int init_size = ThreadService::get_live_thread_count();
879 _threads_array = new GrowableArray<instanceHandle>(init_size);
880
881 MutexLockerEx ml(Threads_lock);
882
883 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
884 // skips JavaThreads in the process of exiting
885 // and also skips VM internal JavaThreads
886 // Threads in _thread_new or _thread_new_trans state are included.
887 // i.e. threads have been started but not yet running.
888 if (jt->threadObj() == NULL ||
889 jt->is_exiting() ||
890 !java_lang_Thread::is_alive(jt->threadObj()) ||
891 jt->is_hidden_from_external_view()) {
892 continue;
893 }
894
895 // skip agent threads
896 if (!include_jvmti_agent_threads && jt->is_jvmti_agent_thread()) {
897 continue;
898 }
899
900 // skip jni threads in the process of attaching
901 if (!include_jni_attaching_threads && jt->is_attaching_via_jni()) {
902 continue;
903 }
904
905 instanceHandle h(cur_thread, (instanceOop) jt->threadObj());
906 _threads_array->append(h);
907 }
908 }