1 /*
2 * Copyright (c) 2003, 2018, 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 "memory/resourceArea.hpp"
31 #include "oops/instanceKlass.hpp"
32 #include "oops/objArrayOop.inline.hpp"
33 #include "oops/oop.inline.hpp"
34 #include "runtime/atomic.hpp"
35 #include "runtime/handles.inline.hpp"
36 #include "runtime/init.hpp"
37 #include "runtime/thread.inline.hpp"
38 #include "runtime/threadSMR.inline.hpp"
39 #include "runtime/vframe.hpp"
40 #include "runtime/vmThread.hpp"
41 #include "runtime/vm_operations.hpp"
42 #include "services/threadService.hpp"
43
44 // TODO: we need to define a naming convention for perf counters
45 // to distinguish counters for:
46 // - standard JSR174 use
47 // - Hotspot extension (public and committed)
48 // - Hotspot extension (private/internal and uncommitted)
49
50 // Default is disabled.
51 bool ThreadService::_thread_monitoring_contention_enabled = false;
52 bool ThreadService::_thread_cpu_time_enabled = false;
53 bool ThreadService::_thread_allocated_memory_enabled = false;
54
55 PerfCounter* ThreadService::_total_threads_count = NULL;
56 PerfVariable* ThreadService::_live_threads_count = NULL;
57 PerfVariable* ThreadService::_peak_threads_count = NULL;
58 PerfVariable* ThreadService::_daemon_threads_count = NULL;
59 volatile int ThreadService::_exiting_threads_count = 0;
60 volatile int ThreadService::_exiting_daemon_threads_count = 0;
61
62 ThreadDumpResult* ThreadService::_threaddump_list = NULL;
63
64 static const int INITIAL_ARRAY_SIZE = 10;
65
66 void ThreadService::init() {
67 EXCEPTION_MARK;
68
69 // These counters are for java.lang.management API support.
70 // They are created even if -XX:-UsePerfData is set and in
71 // that case, they will be allocated on C heap.
72
73 _total_threads_count =
74 PerfDataManager::create_counter(JAVA_THREADS, "started",
75 PerfData::U_Events, CHECK);
76
77 _live_threads_count =
78 PerfDataManager::create_variable(JAVA_THREADS, "live",
79 PerfData::U_None, CHECK);
80
81 _peak_threads_count =
82 PerfDataManager::create_variable(JAVA_THREADS, "livePeak",
83 PerfData::U_None, CHECK);
84
85 _daemon_threads_count =
86 PerfDataManager::create_variable(JAVA_THREADS, "daemon",
87 PerfData::U_None, CHECK);
88
89 if (os::is_thread_cpu_time_supported()) {
90 _thread_cpu_time_enabled = true;
91 }
92
93 _thread_allocated_memory_enabled = true; // Always on, so enable it
94 }
95
96 void ThreadService::reset_peak_thread_count() {
97 // Acquire the lock to update the peak thread count
98 // to synchronize with thread addition and removal.
99 MutexLockerEx mu(Threads_lock);
100 _peak_threads_count->set_value(get_live_thread_count());
101 }
102
103 void ThreadService::add_thread(JavaThread* thread, bool daemon) {
104 // Do not count VM internal or JVMTI agent threads
105 if (thread->is_hidden_from_external_view() ||
106 thread->is_jvmti_agent_thread()) {
107 return;
108 }
109
110 _total_threads_count->inc();
111 _live_threads_count->inc();
112
113 if (_live_threads_count->get_value() > _peak_threads_count->get_value()) {
114 _peak_threads_count->set_value(_live_threads_count->get_value());
115 }
116
117 if (daemon) {
118 _daemon_threads_count->inc();
119 }
120 }
121
122 void ThreadService::remove_thread(JavaThread* thread, bool daemon) {
123 Atomic::dec(&_exiting_threads_count);
124
125 if (thread->is_hidden_from_external_view() ||
126 thread->is_jvmti_agent_thread()) {
127 return;
128 }
129
130 _live_threads_count->set_value(_live_threads_count->get_value() - 1);
131
132 if (daemon) {
133 _daemon_threads_count->set_value(_daemon_threads_count->get_value() - 1);
134 Atomic::dec(&_exiting_daemon_threads_count);
135 }
136 }
137
138 void ThreadService::current_thread_exiting(JavaThread* jt) {
139 assert(jt == JavaThread::current(), "Called by current thread");
140 Atomic::inc(&_exiting_threads_count);
141
142 oop threadObj = jt->threadObj();
143 if (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)) {
144 Atomic::inc(&_exiting_daemon_threads_count);
145 }
146 }
147
148 // FIXME: JVMTI should call this function
149 Handle ThreadService::get_current_contended_monitor(JavaThread* thread) {
150 assert(thread != NULL, "should be non-NULL");
151 debug_only(Thread::check_for_dangling_thread_pointer(thread);)
152
153 ObjectMonitor *wait_obj = thread->current_waiting_monitor();
154
155 oop obj = NULL;
156 if (wait_obj != NULL) {
157 // thread is doing an Object.wait() call
158 obj = (oop) wait_obj->object();
159 assert(obj != NULL, "Object.wait() should have an object");
160 } else {
161 ObjectMonitor *enter_obj = thread->current_pending_monitor();
162 if (enter_obj != NULL) {
163 // thread is trying to enter() or raw_enter() an ObjectMonitor.
164 obj = (oop) enter_obj->object();
165 }
166 // If obj == NULL, then ObjectMonitor is raw which doesn't count.
167 }
168
169 Handle h(Thread::current(), obj);
170 return h;
171 }
172
173 bool ThreadService::set_thread_monitoring_contention(bool flag) {
174 MutexLocker m(Management_lock);
175
176 bool prev = _thread_monitoring_contention_enabled;
177 _thread_monitoring_contention_enabled = flag;
178
179 return prev;
180 }
181
182 bool ThreadService::set_thread_cpu_time_enabled(bool flag) {
183 MutexLocker m(Management_lock);
184
185 bool prev = _thread_cpu_time_enabled;
186 _thread_cpu_time_enabled = flag;
187
188 return prev;
189 }
190
191 bool ThreadService::set_thread_allocated_memory_enabled(bool flag) {
192 MutexLocker m(Management_lock);
193
194 bool prev = _thread_allocated_memory_enabled;
195 _thread_allocated_memory_enabled = flag;
196
197 return prev;
198 }
199
200 // GC support
201 void ThreadService::oops_do(OopClosure* f) {
202 for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) {
203 dump->oops_do(f);
204 }
205 }
206
207 void ThreadService::metadata_do(void f(Metadata*)) {
208 for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) {
209 dump->metadata_do(f);
210 }
211 }
212
213 void ThreadService::add_thread_dump(ThreadDumpResult* dump) {
214 MutexLocker ml(Management_lock);
215 if (_threaddump_list == NULL) {
216 _threaddump_list = dump;
217 } else {
218 dump->set_next(_threaddump_list);
219 _threaddump_list = dump;
220 }
221 }
222
223 void ThreadService::remove_thread_dump(ThreadDumpResult* dump) {
224 MutexLocker ml(Management_lock);
225
226 ThreadDumpResult* prev = NULL;
227 bool found = false;
228 for (ThreadDumpResult* d = _threaddump_list; d != NULL; prev = d, d = d->next()) {
229 if (d == dump) {
230 if (prev == NULL) {
231 _threaddump_list = dump->next();
232 } else {
233 prev->set_next(dump->next());
234 }
235 found = true;
236 break;
237 }
238 }
239 assert(found, "The threaddump result to be removed must exist.");
240 }
241
242 // Dump stack trace of threads specified in the given threads array.
243 // Returns StackTraceElement[][] each element is the stack trace of a thread in
244 // the corresponding entry in the given threads array
245 Handle ThreadService::dump_stack_traces(GrowableArray<instanceHandle>* threads,
246 int num_threads,
247 TRAPS) {
248 assert(num_threads > 0, "just checking");
249
250 ThreadDumpResult dump_result;
251 VM_ThreadDump op(&dump_result,
252 threads,
253 num_threads,
254 -1, /* entire stack */
255 false, /* with locked monitors */
256 false /* with locked synchronizers */);
257 VMThread::execute(&op);
258
259 // Allocate the resulting StackTraceElement[][] object
260
261 ResourceMark rm(THREAD);
262 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_StackTraceElement_array(), true, CHECK_NH);
263 ObjArrayKlass* ik = ObjArrayKlass::cast(k);
264 objArrayOop r = oopFactory::new_objArray(ik, num_threads, CHECK_NH);
265 objArrayHandle result_obj(THREAD, r);
266
267 int num_snapshots = dump_result.num_snapshots();
268 assert(num_snapshots == num_threads, "Must have num_threads thread snapshots");
269 assert(num_snapshots == 0 || dump_result.t_list_has_been_set(), "ThreadsList must have been set if we have a snapshot");
270 int i = 0;
271 for (ThreadSnapshot* ts = dump_result.snapshots(); ts != NULL; i++, ts = ts->next()) {
272 ThreadStackTrace* stacktrace = ts->get_stack_trace();
273 if (stacktrace == NULL) {
274 // No stack trace
275 result_obj->obj_at_put(i, NULL);
276 } else {
277 // Construct an array of java/lang/StackTraceElement object
278 Handle backtrace_h = stacktrace->allocate_fill_stack_trace_element_array(CHECK_NH);
279 result_obj->obj_at_put(i, backtrace_h());
280 }
281 }
282
283 return result_obj;
284 }
285
286 void ThreadService::reset_contention_count_stat(JavaThread* thread) {
287 ThreadStatistics* stat = thread->get_thread_stat();
288 if (stat != NULL) {
289 stat->reset_count_stat();
290 }
291 }
292
293 void ThreadService::reset_contention_time_stat(JavaThread* thread) {
294 ThreadStatistics* stat = thread->get_thread_stat();
295 if (stat != NULL) {
296 stat->reset_time_stat();
297 }
298 }
299
300 // Find deadlocks involving object monitors and concurrent locks if concurrent_locks is true
301 DeadlockCycle* ThreadService::find_deadlocks_at_safepoint(ThreadsList * t_list, bool concurrent_locks) {
302 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
303
304 // This code was modified from the original Threads::find_deadlocks code.
305 int globalDfn = 0, thisDfn;
306 ObjectMonitor* waitingToLockMonitor = NULL;
307 oop waitingToLockBlocker = NULL;
308 bool blocked_on_monitor = false;
309 JavaThread *currentThread, *previousThread;
310 int num_deadlocks = 0;
311
312 // Initialize the depth-first-number for each JavaThread.
313 JavaThreadIterator jti(t_list);
314 for (JavaThread* jt = jti.first(); jt != NULL; jt = jti.next()) {
315 jt->set_depth_first_number(-1);
316 }
317
318 DeadlockCycle* deadlocks = NULL;
319 DeadlockCycle* last = NULL;
320 DeadlockCycle* cycle = new DeadlockCycle();
321 for (JavaThread* jt = jti.first(); jt != NULL; jt = jti.next()) {
322 if (jt->depth_first_number() >= 0) {
323 // this thread was already visited
324 continue;
325 }
326
327 thisDfn = globalDfn;
328 jt->set_depth_first_number(globalDfn++);
329 previousThread = jt;
330 currentThread = jt;
331
332 cycle->reset();
333
334 // When there is a deadlock, all the monitors involved in the dependency
335 // cycle must be contended and heavyweight. So we only care about the
336 // heavyweight monitor a thread is waiting to lock.
337 waitingToLockMonitor = (ObjectMonitor*)jt->current_pending_monitor();
338 if (concurrent_locks) {
339 waitingToLockBlocker = jt->current_park_blocker();
340 }
341 while (waitingToLockMonitor != NULL || waitingToLockBlocker != NULL) {
342 cycle->add_thread(currentThread);
343 if (waitingToLockMonitor != NULL) {
344 address currentOwner = (address)waitingToLockMonitor->owner();
345 if (currentOwner != NULL) {
346 currentThread = Threads::owning_thread_from_monitor_owner(t_list,
347 currentOwner);
348 if (currentThread == NULL) {
349 // This function is called at a safepoint so the JavaThread
350 // that owns waitingToLockMonitor should be findable, but
351 // if it is not findable, then the previous currentThread is
352 // blocked permanently. We record this as a deadlock.
353 num_deadlocks++;
354
355 cycle->set_deadlock(true);
356
357 // add this cycle to the deadlocks list
358 if (deadlocks == NULL) {
359 deadlocks = cycle;
360 } else {
361 last->set_next(cycle);
362 }
363 last = cycle;
364 cycle = new DeadlockCycle();
365 break;
366 }
367 }
368 } else {
369 if (concurrent_locks) {
370 if (waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
371 oop threadObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
372 // This JavaThread (if there is one) is protected by the
373 // ThreadsListSetter in VM_FindDeadlocks::doit().
374 currentThread = threadObj != NULL ? java_lang_Thread::thread(threadObj) : NULL;
375 } else {
376 currentThread = NULL;
377 }
378 }
379 }
380
381 if (currentThread == NULL) {
382 // No dependency on another thread
383 break;
384 }
385 if (currentThread->depth_first_number() < 0) {
386 // First visit to this thread
387 currentThread->set_depth_first_number(globalDfn++);
388 } else if (currentThread->depth_first_number() < thisDfn) {
389 // Thread already visited, and not on a (new) cycle
390 break;
391 } else if (currentThread == previousThread) {
392 // Self-loop, ignore
393 break;
394 } else {
395 // We have a (new) cycle
396 num_deadlocks++;
397
398 cycle->set_deadlock(true);
399
400 // add this cycle to the deadlocks list
401 if (deadlocks == NULL) {
402 deadlocks = cycle;
403 } else {
404 last->set_next(cycle);
405 }
406 last = cycle;
407 cycle = new DeadlockCycle();
408 break;
409 }
410 previousThread = currentThread;
411 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
412 if (concurrent_locks) {
413 waitingToLockBlocker = currentThread->current_park_blocker();
414 }
415 }
416
417 }
418 delete cycle;
419 return deadlocks;
420 }
421
422 ThreadDumpResult::ThreadDumpResult() : _num_threads(0), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL), _setter() {
423
424 // Create a new ThreadDumpResult object and append to the list.
425 // If GC happens before this function returns, Method*
426 // in the stack trace will be visited.
427 ThreadService::add_thread_dump(this);
428 }
429
430 ThreadDumpResult::ThreadDumpResult(int num_threads) : _num_threads(num_threads), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL), _setter() {
431 // Create a new ThreadDumpResult object and append to the list.
432 // If GC happens before this function returns, oops
433 // will be visited.
434 ThreadService::add_thread_dump(this);
435 }
436
437 ThreadDumpResult::~ThreadDumpResult() {
438 ThreadService::remove_thread_dump(this);
439
440 // free all the ThreadSnapshot objects created during
441 // the VM_ThreadDump operation
442 ThreadSnapshot* ts = _snapshots;
443 while (ts != NULL) {
444 ThreadSnapshot* p = ts;
445 ts = ts->next();
446 delete p;
447 }
448 }
449
450
451 void ThreadDumpResult::add_thread_snapshot(ThreadSnapshot* ts) {
452 assert(_num_threads == 0 || _num_snapshots < _num_threads,
453 "_num_snapshots must be less than _num_threads");
454 _num_snapshots++;
455 if (_snapshots == NULL) {
456 _snapshots = ts;
457 } else {
458 _last->set_next(ts);
459 }
460 _last = ts;
461 }
462
463 void ThreadDumpResult::oops_do(OopClosure* f) {
464 for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) {
465 ts->oops_do(f);
466 }
467 }
468
469 void ThreadDumpResult::metadata_do(void f(Metadata*)) {
470 for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) {
471 ts->metadata_do(f);
472 }
473 }
474
475 ThreadsList* ThreadDumpResult::t_list() {
476 return _setter.list();
477 }
478
479 StackFrameInfo::StackFrameInfo(javaVFrame* jvf, bool with_lock_info) {
480 _method = jvf->method();
481 _bci = jvf->bci();
482 _class_holder = _method->method_holder()->klass_holder();
483 _locked_monitors = NULL;
484 if (with_lock_info) {
485 ResourceMark rm;
486 GrowableArray<MonitorInfo*>* list = jvf->locked_monitors();
487 int length = list->length();
488 if (length > 0) {
489 _locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(length, true);
490 for (int i = 0; i < length; i++) {
491 MonitorInfo* monitor = list->at(i);
492 assert(monitor->owner() != NULL, "This monitor must have an owning object");
493 _locked_monitors->append(monitor->owner());
494 }
495 }
496 }
497 }
498
499 void StackFrameInfo::oops_do(OopClosure* f) {
500 if (_locked_monitors != NULL) {
501 int length = _locked_monitors->length();
502 for (int i = 0; i < length; i++) {
503 f->do_oop((oop*) _locked_monitors->adr_at(i));
504 }
505 }
506 f->do_oop(&_class_holder);
507 }
508
509 void StackFrameInfo::metadata_do(void f(Metadata*)) {
510 f(_method);
511 }
512
513 void StackFrameInfo::print_on(outputStream* st) const {
514 ResourceMark rm;
515 java_lang_Throwable::print_stack_element(st, method(), bci());
516 int len = (_locked_monitors != NULL ? _locked_monitors->length() : 0);
517 for (int i = 0; i < len; i++) {
518 oop o = _locked_monitors->at(i);
519 st->print_cr("\t- locked <" INTPTR_FORMAT "> (a %s)", p2i(o), o->klass()->external_name());
520 }
521
522 }
523
524 // Iterate through monitor cache to find JNI locked monitors
525 class InflatedMonitorsClosure: public MonitorClosure {
526 private:
527 ThreadStackTrace* _stack_trace;
528 Thread* _thread;
529 public:
530 InflatedMonitorsClosure(Thread* t, ThreadStackTrace* st) {
531 _thread = t;
532 _stack_trace = st;
533 }
534 void do_monitor(ObjectMonitor* mid) {
535 if (mid->owner() == _thread) {
536 oop object = (oop) mid->object();
537 if (!_stack_trace->is_owned_monitor_on_stack(object)) {
538 _stack_trace->add_jni_locked_monitor(object);
539 }
540 }
541 }
542 };
543
544 ThreadStackTrace::ThreadStackTrace(JavaThread* t, bool with_locked_monitors) {
545 _thread = t;
546 _frames = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<StackFrameInfo*>(INITIAL_ARRAY_SIZE, true);
547 _depth = 0;
548 _with_locked_monitors = with_locked_monitors;
549 if (_with_locked_monitors) {
550 _jni_locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(INITIAL_ARRAY_SIZE, true);
551 } else {
552 _jni_locked_monitors = NULL;
553 }
554 }
555
556 ThreadStackTrace::~ThreadStackTrace() {
557 for (int i = 0; i < _frames->length(); i++) {
558 delete _frames->at(i);
559 }
560 delete _frames;
561 if (_jni_locked_monitors != NULL) {
562 delete _jni_locked_monitors;
563 }
564 }
565
566 void ThreadStackTrace::dump_stack_at_safepoint(int maxDepth) {
567 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
568
569 if (_thread->has_last_Java_frame()) {
570 RegisterMap reg_map(_thread);
571 vframe* start_vf = _thread->last_java_vframe(®_map);
572 int count = 0;
573 for (vframe* f = start_vf; f; f = f->sender() ) {
574 if (maxDepth >= 0 && count == maxDepth) {
575 // Skip frames if more than maxDepth
576 break;
577 }
578 if (f->is_java_frame()) {
579 javaVFrame* jvf = javaVFrame::cast(f);
580 add_stack_frame(jvf);
581 count++;
582 } else {
583 // Ignore non-Java frames
584 }
585 }
586 }
587
588 if (_with_locked_monitors) {
589 // Iterate inflated monitors and find monitors locked by this thread
590 // not found in the stack
591 InflatedMonitorsClosure imc(_thread, this);
592 ObjectSynchronizer::monitors_iterate(&imc);
593 }
594 }
595
596
597 bool ThreadStackTrace::is_owned_monitor_on_stack(oop object) {
598 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
599
600 bool found = false;
601 int num_frames = get_stack_depth();
602 for (int depth = 0; depth < num_frames; depth++) {
603 StackFrameInfo* frame = stack_frame_at(depth);
604 int len = frame->num_locked_monitors();
605 GrowableArray<oop>* locked_monitors = frame->locked_monitors();
606 for (int j = 0; j < len; j++) {
607 oop monitor = locked_monitors->at(j);
608 assert(monitor != NULL, "must be a Java object");
609 if (monitor == object) {
610 found = true;
611 break;
612 }
613 }
614 }
615 return found;
616 }
617
618 Handle ThreadStackTrace::allocate_fill_stack_trace_element_array(TRAPS) {
619 InstanceKlass* ik = SystemDictionary::StackTraceElement_klass();
620 assert(ik != NULL, "must be loaded in 1.4+");
621
622 // Allocate an array of java/lang/StackTraceElement object
623 objArrayOop ste = oopFactory::new_objArray(ik, _depth, CHECK_NH);
624 objArrayHandle backtrace(THREAD, ste);
625 for (int j = 0; j < _depth; j++) {
626 StackFrameInfo* frame = _frames->at(j);
627 methodHandle mh(THREAD, frame->method());
628 oop element = java_lang_StackTraceElement::create(mh, frame->bci(), CHECK_NH);
629 backtrace->obj_at_put(j, element);
630 }
631 return backtrace;
632 }
633
634 void ThreadStackTrace::add_stack_frame(javaVFrame* jvf) {
635 StackFrameInfo* frame = new StackFrameInfo(jvf, _with_locked_monitors);
636 _frames->append(frame);
637 _depth++;
638 }
639
640 void ThreadStackTrace::oops_do(OopClosure* f) {
641 int length = _frames->length();
642 for (int i = 0; i < length; i++) {
643 _frames->at(i)->oops_do(f);
644 }
645
646 length = (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0);
647 for (int j = 0; j < length; j++) {
648 f->do_oop((oop*) _jni_locked_monitors->adr_at(j));
649 }
650 }
651
652 void ThreadStackTrace::metadata_do(void f(Metadata*)) {
653 int length = _frames->length();
654 for (int i = 0; i < length; i++) {
655 _frames->at(i)->metadata_do(f);
656 }
657 }
658
659
660 ConcurrentLocksDump::~ConcurrentLocksDump() {
661 if (_retain_map_on_free) {
662 return;
663 }
664
665 for (ThreadConcurrentLocks* t = _map; t != NULL;) {
666 ThreadConcurrentLocks* tcl = t;
667 t = t->next();
668 delete tcl;
669 }
670 }
671
672 void ConcurrentLocksDump::dump_at_safepoint() {
673 // dump all locked concurrent locks
674 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
675
676 ResourceMark rm;
677
678 GrowableArray<oop>* aos_objects = new GrowableArray<oop>(INITIAL_ARRAY_SIZE);
679
680 // Find all instances of AbstractOwnableSynchronizer
681 HeapInspection::find_instances_at_safepoint(SystemDictionary::abstract_ownable_synchronizer_klass(),
682 aos_objects);
683 // Build a map of thread to its owned AQS locks
684 build_map(aos_objects);
685 }
686
687
688 // build a map of JavaThread to all its owned AbstractOwnableSynchronizer
689 void ConcurrentLocksDump::build_map(GrowableArray<oop>* aos_objects) {
690 int length = aos_objects->length();
691 for (int i = 0; i < length; i++) {
692 oop o = aos_objects->at(i);
693 oop owner_thread_obj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(o);
694 if (owner_thread_obj != NULL) {
695 // See comments in ThreadConcurrentLocks to see how this
696 // JavaThread* is protected.
697 JavaThread* thread = java_lang_Thread::thread(owner_thread_obj);
698 assert(o->is_instance(), "Must be an instanceOop");
699 add_lock(thread, (instanceOop) o);
700 }
701 }
702 }
703
704 void ConcurrentLocksDump::add_lock(JavaThread* thread, instanceOop o) {
705 ThreadConcurrentLocks* tcl = thread_concurrent_locks(thread);
706 if (tcl != NULL) {
707 tcl->add_lock(o);
708 return;
709 }
710
711 // First owned lock found for this thread
712 tcl = new ThreadConcurrentLocks(thread);
713 tcl->add_lock(o);
714 if (_map == NULL) {
715 _map = tcl;
716 } else {
717 _last->set_next(tcl);
718 }
719 _last = tcl;
720 }
721
722 ThreadConcurrentLocks* ConcurrentLocksDump::thread_concurrent_locks(JavaThread* thread) {
723 for (ThreadConcurrentLocks* tcl = _map; tcl != NULL; tcl = tcl->next()) {
724 if (tcl->java_thread() == thread) {
725 return tcl;
726 }
727 }
728 return NULL;
729 }
730
731 void ConcurrentLocksDump::print_locks_on(JavaThread* t, outputStream* st) {
732 st->print_cr(" Locked ownable synchronizers:");
733 ThreadConcurrentLocks* tcl = thread_concurrent_locks(t);
734 GrowableArray<instanceOop>* locks = (tcl != NULL ? tcl->owned_locks() : NULL);
735 if (locks == NULL || locks->is_empty()) {
736 st->print_cr("\t- None");
737 st->cr();
738 return;
739 }
740
741 for (int i = 0; i < locks->length(); i++) {
742 instanceOop obj = locks->at(i);
743 st->print_cr("\t- <" INTPTR_FORMAT "> (a %s)", p2i(obj), obj->klass()->external_name());
744 }
745 st->cr();
746 }
747
748 ThreadConcurrentLocks::ThreadConcurrentLocks(JavaThread* thread) {
749 _thread = thread;
750 _owned_locks = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<instanceOop>(INITIAL_ARRAY_SIZE, true);
751 _next = NULL;
752 }
753
754 ThreadConcurrentLocks::~ThreadConcurrentLocks() {
755 delete _owned_locks;
756 }
757
758 void ThreadConcurrentLocks::add_lock(instanceOop o) {
759 _owned_locks->append(o);
760 }
761
762 void ThreadConcurrentLocks::oops_do(OopClosure* f) {
763 int length = _owned_locks->length();
764 for (int i = 0; i < length; i++) {
765 f->do_oop((oop*) _owned_locks->adr_at(i));
766 }
767 }
768
769 ThreadStatistics::ThreadStatistics() {
770 _contended_enter_count = 0;
771 _monitor_wait_count = 0;
772 _sleep_count = 0;
773 _count_pending_reset = false;
774 _timer_pending_reset = false;
775 memset((void*) _perf_recursion_counts, 0, sizeof(_perf_recursion_counts));
776 }
777
778 ThreadSnapshot::ThreadSnapshot(ThreadsList * t_list, JavaThread* thread) {
779 _thread = thread;
780 _threadObj = thread->threadObj();
781 _stack_trace = NULL;
782 _concurrent_locks = NULL;
783 _next = NULL;
784
785 ThreadStatistics* stat = thread->get_thread_stat();
786 _contended_enter_ticks = stat->contended_enter_ticks();
787 _contended_enter_count = stat->contended_enter_count();
788 _monitor_wait_ticks = stat->monitor_wait_ticks();
789 _monitor_wait_count = stat->monitor_wait_count();
790 _sleep_ticks = stat->sleep_ticks();
791 _sleep_count = stat->sleep_count();
792
793 _blocker_object = NULL;
794 _blocker_object_owner = NULL;
795
796 _thread_status = java_lang_Thread::get_thread_status(_threadObj);
797 _is_ext_suspended = thread->is_being_ext_suspended();
798 _is_in_native = (thread->thread_state() == _thread_in_native);
799
800 if (_thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER ||
801 _thread_status == java_lang_Thread::IN_OBJECT_WAIT ||
802 _thread_status == java_lang_Thread::IN_OBJECT_WAIT_TIMED) {
803
804 Handle obj = ThreadService::get_current_contended_monitor(thread);
805 if (obj() == NULL) {
806 // monitor no longer exists; thread is not blocked
807 _thread_status = java_lang_Thread::RUNNABLE;
808 } else {
809 _blocker_object = obj();
810 JavaThread* owner = ObjectSynchronizer::get_lock_owner(t_list, obj);
811 if ((owner == NULL && _thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER)
812 || (owner != NULL && owner->is_attaching_via_jni())) {
813 // ownership information of the monitor is not available
814 // (may no longer be owned or releasing to some other thread)
815 // make this thread in RUNNABLE state.
816 // And when the owner thread is in attaching state, the java thread
817 // is not completely initialized. For example thread name and id
818 // and may not be set, so hide the attaching thread.
819 _thread_status = java_lang_Thread::RUNNABLE;
820 _blocker_object = NULL;
821 } else if (owner != NULL) {
822 _blocker_object_owner = owner->threadObj();
823 }
824 }
825 }
826
827 // Support for JSR-166 locks
828 if (JDK_Version::current().supports_thread_park_blocker() &&
829 (_thread_status == java_lang_Thread::PARKED ||
830 _thread_status == java_lang_Thread::PARKED_TIMED)) {
831
832 _blocker_object = thread->current_park_blocker();
833 if (_blocker_object != NULL && _blocker_object->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
834 _blocker_object_owner = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(_blocker_object);
835 }
836 }
837 }
838
839 ThreadSnapshot::~ThreadSnapshot() {
840 delete _stack_trace;
841 delete _concurrent_locks;
842 }
843
844 void ThreadSnapshot::dump_stack_at_safepoint(int max_depth, bool with_locked_monitors) {
845 _stack_trace = new ThreadStackTrace(_thread, with_locked_monitors);
846 _stack_trace->dump_stack_at_safepoint(max_depth);
847 }
848
849
850 void ThreadSnapshot::oops_do(OopClosure* f) {
851 f->do_oop(&_threadObj);
852 f->do_oop(&_blocker_object);
853 f->do_oop(&_blocker_object_owner);
854 if (_stack_trace != NULL) {
855 _stack_trace->oops_do(f);
856 }
857 if (_concurrent_locks != NULL) {
858 _concurrent_locks->oops_do(f);
859 }
860 }
861
862 void ThreadSnapshot::metadata_do(void f(Metadata*)) {
863 if (_stack_trace != NULL) {
864 _stack_trace->metadata_do(f);
865 }
866 }
867
868
869 DeadlockCycle::DeadlockCycle() {
870 _is_deadlock = false;
871 _threads = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<JavaThread*>(INITIAL_ARRAY_SIZE, true);
872 _next = NULL;
873 }
874
875 DeadlockCycle::~DeadlockCycle() {
876 delete _threads;
877 }
878
879 void DeadlockCycle::print_on_with(ThreadsList * t_list, outputStream* st) const {
880 st->cr();
881 st->print_cr("Found one Java-level deadlock:");
882 st->print("=============================");
883
884 JavaThread* currentThread;
885 ObjectMonitor* waitingToLockMonitor;
886 oop waitingToLockBlocker;
887 int len = _threads->length();
888 for (int i = 0; i < len; i++) {
889 currentThread = _threads->at(i);
890 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
891 waitingToLockBlocker = currentThread->current_park_blocker();
892 st->cr();
893 st->print_cr("\"%s\":", currentThread->get_thread_name());
894 const char* owner_desc = ",\n which is held by";
895 if (waitingToLockMonitor != NULL) {
896 st->print(" waiting to lock monitor " INTPTR_FORMAT, p2i(waitingToLockMonitor));
897 oop obj = (oop)waitingToLockMonitor->object();
898 if (obj != NULL) {
899 st->print(" (object " INTPTR_FORMAT ", a %s)", p2i(obj),
900 obj->klass()->external_name());
901
902 if (!currentThread->current_pending_monitor_is_from_java()) {
903 owner_desc = "\n in JNI, which is held by";
904 }
905 } else {
906 // No Java object associated - a JVMTI raw monitor
907 owner_desc = " (JVMTI raw monitor),\n which is held by";
908 }
909 currentThread = Threads::owning_thread_from_monitor_owner(t_list,
910 (address)waitingToLockMonitor->owner());
911 if (currentThread == NULL) {
912 // The deadlock was detected at a safepoint so the JavaThread
913 // that owns waitingToLockMonitor should be findable, but
914 // if it is not findable, then the previous currentThread is
915 // blocked permanently.
916 st->print("%s UNKNOWN_owner_addr=" PTR_FORMAT, owner_desc,
917 p2i(waitingToLockMonitor->owner()));
918 continue;
919 }
920 } else {
921 st->print(" waiting for ownable synchronizer " INTPTR_FORMAT ", (a %s)",
922 p2i(waitingToLockBlocker),
923 waitingToLockBlocker->klass()->external_name());
924 assert(waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass()),
925 "Must be an AbstractOwnableSynchronizer");
926 oop ownerObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
927 currentThread = java_lang_Thread::thread(ownerObj);
928 assert(currentThread != NULL, "AbstractOwnableSynchronizer owning thread is unexpectedly NULL");
929 }
930 st->print("%s \"%s\"", owner_desc, currentThread->get_thread_name());
931 }
932
933 st->cr();
934 st->cr();
935
936 // Print stack traces
937 bool oldJavaMonitorsInStackTrace = JavaMonitorsInStackTrace;
938 JavaMonitorsInStackTrace = true;
939 st->print_cr("Java stack information for the threads listed above:");
940 st->print_cr("===================================================");
941 for (int j = 0; j < len; j++) {
942 currentThread = _threads->at(j);
943 st->print_cr("\"%s\":", currentThread->get_thread_name());
944 currentThread->print_stack_on(st);
945 }
946 JavaMonitorsInStackTrace = oldJavaMonitorsInStackTrace;
947 }
948
949 ThreadsListEnumerator::ThreadsListEnumerator(Thread* cur_thread,
950 bool include_jvmti_agent_threads,
951 bool include_jni_attaching_threads) {
952 assert(cur_thread == Thread::current(), "Check current thread");
953
954 int init_size = ThreadService::get_live_thread_count();
955 _threads_array = new GrowableArray<instanceHandle>(init_size);
956
957 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
958 // skips JavaThreads in the process of exiting
959 // and also skips VM internal JavaThreads
960 // Threads in _thread_new or _thread_new_trans state are included.
961 // i.e. threads have been started but not yet running.
962 if (jt->threadObj() == NULL ||
963 jt->is_exiting() ||
964 !java_lang_Thread::is_alive(jt->threadObj()) ||
965 jt->is_hidden_from_external_view()) {
966 continue;
967 }
968
969 // skip agent threads
970 if (!include_jvmti_agent_threads && jt->is_jvmti_agent_thread()) {
971 continue;
972 }
973
974 // skip jni threads in the process of attaching
975 if (!include_jni_attaching_threads && jt->is_attaching_via_jni()) {
976 continue;
977 }
978
979 instanceHandle h(cur_thread, (instanceOop) jt->threadObj());
980 _threads_array->append(h);
981 }
982 }