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/objectMonitor.inline.hpp"
38 #include "runtime/thread.inline.hpp"
39 #include "runtime/threadSMR.inline.hpp"
40 #include "runtime/vframe.hpp"
41 #include "runtime/vmThread.hpp"
42 #include "runtime/vm_operations.hpp"
43 #include "services/threadService.hpp"
44
45 // TODO: we need to define a naming convention for perf counters
46 // to distinguish counters for:
47 // - standard JSR174 use
48 // - Hotspot extension (public and committed)
49 // - Hotspot extension (private/internal and uncommitted)
50
51 // Default is disabled.
52 bool ThreadService::_thread_monitoring_contention_enabled = false;
53 bool ThreadService::_thread_cpu_time_enabled = false;
54 bool ThreadService::_thread_allocated_memory_enabled = false;
55
56 PerfCounter* ThreadService::_total_threads_count = NULL;
57 PerfVariable* ThreadService::_live_threads_count = NULL;
58 PerfVariable* ThreadService::_peak_threads_count = NULL;
59 PerfVariable* ThreadService::_daemon_threads_count = NULL;
60 volatile int ThreadService::_exiting_threads_count = 0;
61 volatile int ThreadService::_exiting_daemon_threads_count = 0;
62
63 ThreadDumpResult* ThreadService::_threaddump_list = NULL;
64
65 static const int INITIAL_ARRAY_SIZE = 10;
66
67 void ThreadService::init() {
68 EXCEPTION_MARK;
69
70 // These counters are for java.lang.management API support.
71 // They are created even if -XX:-UsePerfData is set and in
72 // that case, they will be allocated on C heap.
73
74 _total_threads_count =
75 PerfDataManager::create_counter(JAVA_THREADS, "started",
76 PerfData::U_Events, CHECK);
77
78 _live_threads_count =
79 PerfDataManager::create_variable(JAVA_THREADS, "live",
80 PerfData::U_None, CHECK);
81
82 _peak_threads_count =
83 PerfDataManager::create_variable(JAVA_THREADS, "livePeak",
84 PerfData::U_None, CHECK);
85
86 _daemon_threads_count =
87 PerfDataManager::create_variable(JAVA_THREADS, "daemon",
88 PerfData::U_None, CHECK);
89
90 if (os::is_thread_cpu_time_supported()) {
91 _thread_cpu_time_enabled = true;
92 }
93
94 _thread_allocated_memory_enabled = true; // Always on, so enable it
95 }
96
97 void ThreadService::reset_peak_thread_count() {
98 // Acquire the lock to update the peak thread count
99 // to synchronize with thread addition and removal.
100 MutexLockerEx mu(Threads_lock);
101 _peak_threads_count->set_value(get_live_thread_count());
102 }
103
104 void ThreadService::add_thread(JavaThread* thread, bool daemon) {
105 // Do not count VM internal or JVMTI agent threads
106 if (thread->is_hidden_from_external_view() ||
107 thread->is_jvmti_agent_thread()) {
108 return;
109 }
110
111 _total_threads_count->inc();
112 _live_threads_count->inc();
113
114 if (_live_threads_count->get_value() > _peak_threads_count->get_value()) {
115 _peak_threads_count->set_value(_live_threads_count->get_value());
116 }
117
118 if (daemon) {
119 _daemon_threads_count->inc();
120 }
121 }
122
123 void ThreadService::remove_thread(JavaThread* thread, bool daemon) {
124 Atomic::dec(&_exiting_threads_count);
125
126 if (thread->is_hidden_from_external_view() ||
127 thread->is_jvmti_agent_thread()) {
128 return;
129 }
130
131 _live_threads_count->set_value(_live_threads_count->get_value() - 1);
132
133 if (daemon) {
134 _daemon_threads_count->set_value(_daemon_threads_count->get_value() - 1);
135 Atomic::dec(&_exiting_daemon_threads_count);
136 }
137 }
138
139 void ThreadService::current_thread_exiting(JavaThread* jt) {
140 assert(jt == JavaThread::current(), "Called by current thread");
141 Atomic::inc(&_exiting_threads_count);
142
143 oop threadObj = jt->threadObj();
144 if (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)) {
145 Atomic::inc(&_exiting_daemon_threads_count);
146 }
147 }
148
149 // FIXME: JVMTI should call this function
150 Handle ThreadService::get_current_contended_monitor(JavaThread* thread) {
151 assert(thread != NULL, "should be non-NULL");
152 debug_only(Thread::check_for_dangling_thread_pointer(thread);)
153
154 ObjectMonitor *wait_obj = thread->current_waiting_monitor();
155
156 oop obj = NULL;
157 if (wait_obj != NULL) {
158 // thread is doing an Object.wait() call
159 obj = (oop) wait_obj->object();
160 assert(obj != NULL, "Object.wait() should have an object");
161 } else {
162 ObjectMonitor *enter_obj = thread->current_pending_monitor();
163 if (enter_obj != NULL) {
164 // thread is trying to enter() or raw_enter() an ObjectMonitor.
165 obj = (oop) enter_obj->object();
166 }
167 // If obj == NULL, then ObjectMonitor is raw which doesn't count.
168 }
169
170 Handle h(Thread::current(), obj);
171 return h;
172 }
173
174 bool ThreadService::set_thread_monitoring_contention(bool flag) {
175 MutexLocker m(Management_lock);
176
177 bool prev = _thread_monitoring_contention_enabled;
178 _thread_monitoring_contention_enabled = flag;
179
180 return prev;
181 }
182
183 bool ThreadService::set_thread_cpu_time_enabled(bool flag) {
184 MutexLocker m(Management_lock);
185
186 bool prev = _thread_cpu_time_enabled;
187 _thread_cpu_time_enabled = flag;
188
189 return prev;
190 }
191
192 bool ThreadService::set_thread_allocated_memory_enabled(bool flag) {
193 MutexLocker m(Management_lock);
194
195 bool prev = _thread_allocated_memory_enabled;
196 _thread_allocated_memory_enabled = flag;
197
198 return prev;
199 }
200
201 // GC support
202 void ThreadService::oops_do(OopClosure* f) {
203 for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) {
204 dump->oops_do(f);
205 }
206 }
207
208 void ThreadService::metadata_do(void f(Metadata*)) {
209 for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) {
210 dump->metadata_do(f);
211 }
212 }
213
214 void ThreadService::add_thread_dump(ThreadDumpResult* dump) {
215 MutexLocker ml(Management_lock);
216 if (_threaddump_list == NULL) {
217 _threaddump_list = dump;
218 } else {
219 dump->set_next(_threaddump_list);
220 _threaddump_list = dump;
221 }
222 }
223
224 void ThreadService::remove_thread_dump(ThreadDumpResult* dump) {
225 MutexLocker ml(Management_lock);
226
227 ThreadDumpResult* prev = NULL;
228 bool found = false;
229 for (ThreadDumpResult* d = _threaddump_list; d != NULL; prev = d, d = d->next()) {
230 if (d == dump) {
231 if (prev == NULL) {
232 _threaddump_list = dump->next();
233 } else {
234 prev->set_next(dump->next());
235 }
236 found = true;
237 break;
238 }
239 }
240 assert(found, "The threaddump result to be removed must exist.");
241 }
242
243 // Dump stack trace of threads specified in the given threads array.
244 // Returns StackTraceElement[][] each element is the stack trace of a thread in
245 // the corresponding entry in the given threads array
246 Handle ThreadService::dump_stack_traces(GrowableArray<instanceHandle>* threads,
247 int num_threads,
248 TRAPS) {
249 assert(num_threads > 0, "just checking");
250
251 ThreadDumpResult dump_result;
252 VM_ThreadDump op(&dump_result,
253 threads,
254 num_threads,
255 -1, /* entire stack */
256 false, /* with locked monitors */
257 false /* with locked synchronizers */);
258 VMThread::execute(&op);
259
260 // Allocate the resulting StackTraceElement[][] object
261
262 ResourceMark rm(THREAD);
263 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_StackTraceElement_array(), true, CHECK_NH);
264 ObjArrayKlass* ik = ObjArrayKlass::cast(k);
265 objArrayOop r = oopFactory::new_objArray(ik, num_threads, CHECK_NH);
266 objArrayHandle result_obj(THREAD, r);
267
268 int num_snapshots = dump_result.num_snapshots();
269 assert(num_snapshots == num_threads, "Must have num_threads thread snapshots");
270 assert(num_snapshots == 0 || dump_result.t_list_has_been_set(), "ThreadsList must have been set if we have a snapshot");
271 int i = 0;
272 for (ThreadSnapshot* ts = dump_result.snapshots(); ts != NULL; i++, ts = ts->next()) {
273 ThreadStackTrace* stacktrace = ts->get_stack_trace();
274 if (stacktrace == NULL) {
275 // No stack trace
276 result_obj->obj_at_put(i, NULL);
277 } else {
278 // Construct an array of java/lang/StackTraceElement object
279 Handle backtrace_h = stacktrace->allocate_fill_stack_trace_element_array(CHECK_NH);
280 result_obj->obj_at_put(i, backtrace_h());
281 }
282 }
283
284 return result_obj;
285 }
286
287 void ThreadService::reset_contention_count_stat(JavaThread* thread) {
288 ThreadStatistics* stat = thread->get_thread_stat();
289 if (stat != NULL) {
290 stat->reset_count_stat();
291 }
292 }
293
294 void ThreadService::reset_contention_time_stat(JavaThread* thread) {
295 ThreadStatistics* stat = thread->get_thread_stat();
296 if (stat != NULL) {
297 stat->reset_time_stat();
298 }
299 }
300
301 // Find deadlocks involving object monitors and concurrent locks if concurrent_locks is true
302 DeadlockCycle* ThreadService::find_deadlocks_at_safepoint(ThreadsList * t_list, bool concurrent_locks) {
303 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
304
305 // This code was modified from the original Threads::find_deadlocks code.
306 int globalDfn = 0, thisDfn;
307 ObjectMonitor* waitingToLockMonitor = NULL;
308 oop waitingToLockBlocker = NULL;
309 bool blocked_on_monitor = false;
310 JavaThread *currentThread, *previousThread;
311 int num_deadlocks = 0;
312
313 // Initialize the depth-first-number for each JavaThread.
314 JavaThreadIterator jti(t_list);
315 for (JavaThread* jt = jti.first(); jt != NULL; jt = jti.next()) {
316 jt->set_depth_first_number(-1);
317 }
318
319 DeadlockCycle* deadlocks = NULL;
320 DeadlockCycle* last = NULL;
321 DeadlockCycle* cycle = new DeadlockCycle();
322 for (JavaThread* jt = jti.first(); jt != NULL; jt = jti.next()) {
323 if (jt->depth_first_number() >= 0) {
324 // this thread was already visited
325 continue;
326 }
327
328 thisDfn = globalDfn;
329 jt->set_depth_first_number(globalDfn++);
330 previousThread = jt;
331 currentThread = jt;
332
333 cycle->reset();
334
335 // When there is a deadlock, all the monitors involved in the dependency
336 // cycle must be contended and heavyweight. So we only care about the
337 // heavyweight monitor a thread is waiting to lock.
338 waitingToLockMonitor = (ObjectMonitor*)jt->current_pending_monitor();
339 if (concurrent_locks) {
340 waitingToLockBlocker = jt->current_park_blocker();
341 }
342 while (waitingToLockMonitor != NULL || waitingToLockBlocker != NULL) {
343 cycle->add_thread(currentThread);
344 if (waitingToLockMonitor != NULL) {
345 address currentOwner = (address)waitingToLockMonitor->owner();
346 if (currentOwner != NULL) {
347 currentThread = Threads::owning_thread_from_monitor_owner(t_list,
348 currentOwner);
349 if (currentThread == NULL) {
350 // This function is called at a safepoint so the JavaThread
351 // that owns waitingToLockMonitor should be findable, but
352 // if it is not findable, then the previous currentThread is
353 // blocked permanently. We record this as a deadlock.
354 num_deadlocks++;
355
356 cycle->set_deadlock(true);
357
358 // add this cycle to the deadlocks list
359 if (deadlocks == NULL) {
360 deadlocks = cycle;
361 } else {
362 last->set_next(cycle);
363 }
364 last = cycle;
365 cycle = new DeadlockCycle();
366 break;
367 }
368 }
369 } else {
370 if (concurrent_locks) {
371 if (waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
372 oop threadObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
373 // This JavaThread (if there is one) is protected by the
374 // ThreadsListSetter in VM_FindDeadlocks::doit().
375 currentThread = threadObj != NULL ? java_lang_Thread::thread(threadObj) : NULL;
376 } else {
377 currentThread = NULL;
378 }
379 }
380 }
381
382 if (currentThread == NULL) {
383 // No dependency on another thread
384 break;
385 }
386 if (currentThread->depth_first_number() < 0) {
387 // First visit to this thread
388 currentThread->set_depth_first_number(globalDfn++);
389 } else if (currentThread->depth_first_number() < thisDfn) {
390 // Thread already visited, and not on a (new) cycle
391 break;
392 } else if (currentThread == previousThread) {
393 // Self-loop, ignore
394 break;
395 } else {
396 // We have a (new) cycle
397 num_deadlocks++;
398
399 cycle->set_deadlock(true);
400
401 // add this cycle to the deadlocks list
402 if (deadlocks == NULL) {
403 deadlocks = cycle;
404 } else {
405 last->set_next(cycle);
406 }
407 last = cycle;
408 cycle = new DeadlockCycle();
409 break;
410 }
411 previousThread = currentThread;
412 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
413 if (concurrent_locks) {
414 waitingToLockBlocker = currentThread->current_park_blocker();
415 }
416 }
417
418 }
419 delete cycle;
420 return deadlocks;
421 }
422
423 ThreadDumpResult::ThreadDumpResult() : _num_threads(0), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL), _setter() {
424
425 // Create a new ThreadDumpResult object and append to the list.
426 // If GC happens before this function returns, Method*
427 // in the stack trace will be visited.
428 ThreadService::add_thread_dump(this);
429 }
430
431 ThreadDumpResult::ThreadDumpResult(int num_threads) : _num_threads(num_threads), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL), _setter() {
432 // Create a new ThreadDumpResult object and append to the list.
433 // If GC happens before this function returns, oops
434 // will be visited.
435 ThreadService::add_thread_dump(this);
436 }
437
438 ThreadDumpResult::~ThreadDumpResult() {
439 ThreadService::remove_thread_dump(this);
440
441 // free all the ThreadSnapshot objects created during
442 // the VM_ThreadDump operation
443 ThreadSnapshot* ts = _snapshots;
444 while (ts != NULL) {
445 ThreadSnapshot* p = ts;
446 ts = ts->next();
447 delete p;
448 }
449 }
450
451
452 void ThreadDumpResult::add_thread_snapshot(ThreadSnapshot* ts) {
453 assert(_num_threads == 0 || _num_snapshots < _num_threads,
454 "_num_snapshots must be less than _num_threads");
455 _num_snapshots++;
456 if (_snapshots == NULL) {
457 _snapshots = ts;
458 } else {
459 _last->set_next(ts);
460 }
461 _last = ts;
462 }
463
464 void ThreadDumpResult::oops_do(OopClosure* f) {
465 for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) {
466 ts->oops_do(f);
467 }
468 }
469
470 void ThreadDumpResult::metadata_do(void f(Metadata*)) {
471 for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) {
472 ts->metadata_do(f);
473 }
474 }
475
476 ThreadsList* ThreadDumpResult::t_list() {
477 return _setter.list();
478 }
479
480 StackFrameInfo::StackFrameInfo(javaVFrame* jvf, bool with_lock_info) {
481 _method = jvf->method();
482 _bci = jvf->bci();
483 _class_holder = _method->method_holder()->klass_holder();
484 _locked_monitors = NULL;
485 if (with_lock_info) {
486 ResourceMark rm;
487 GrowableArray<MonitorInfo*>* list = jvf->locked_monitors();
488 int length = list->length();
489 if (length > 0) {
490 _locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(length, true);
491 for (int i = 0; i < length; i++) {
492 MonitorInfo* monitor = list->at(i);
493 assert(monitor->owner() != NULL, "This monitor must have an owning object");
494 _locked_monitors->append(monitor->owner());
495 }
496 }
497 }
498 }
499
500 void StackFrameInfo::oops_do(OopClosure* f) {
501 if (_locked_monitors != NULL) {
502 int length = _locked_monitors->length();
503 for (int i = 0; i < length; i++) {
504 f->do_oop((oop*) _locked_monitors->adr_at(i));
505 }
506 }
507 f->do_oop(&_class_holder);
508 }
509
510 void StackFrameInfo::metadata_do(void f(Metadata*)) {
511 f(_method);
512 }
513
514 void StackFrameInfo::print_on(outputStream* st) const {
515 ResourceMark rm;
516 java_lang_Throwable::print_stack_element(st, method(), bci());
517 int len = (_locked_monitors != NULL ? _locked_monitors->length() : 0);
518 for (int i = 0; i < len; i++) {
519 oop o = _locked_monitors->at(i);
520 st->print_cr("\t- locked <" INTPTR_FORMAT "> (a %s)", p2i(o), o->klass()->external_name());
521 }
522
523 }
524
525 // Iterate through monitor cache to find JNI locked monitors
526 class InflatedMonitorsClosure: public MonitorClosure {
527 private:
528 ThreadStackTrace* _stack_trace;
529 Thread* _thread;
530 public:
531 InflatedMonitorsClosure(Thread* t, ThreadStackTrace* st) {
532 _thread = t;
533 _stack_trace = st;
534 }
535 void do_monitor(ObjectMonitor* mid) {
536 if (mid->owner() == _thread) {
537 oop object = (oop) mid->object();
538 if (!_stack_trace->is_owned_monitor_on_stack(object)) {
539 _stack_trace->add_jni_locked_monitor(object);
540 }
541 }
542 }
543 };
544
545 ThreadStackTrace::ThreadStackTrace(JavaThread* t, bool with_locked_monitors) {
546 _thread = t;
547 _frames = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<StackFrameInfo*>(INITIAL_ARRAY_SIZE, true);
548 _depth = 0;
549 _with_locked_monitors = with_locked_monitors;
550 if (_with_locked_monitors) {
551 _jni_locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(INITIAL_ARRAY_SIZE, true);
552 } else {
553 _jni_locked_monitors = NULL;
554 }
555 }
556
557 ThreadStackTrace::~ThreadStackTrace() {
558 for (int i = 0; i < _frames->length(); i++) {
559 delete _frames->at(i);
560 }
561 delete _frames;
562 if (_jni_locked_monitors != NULL) {
563 delete _jni_locked_monitors;
564 }
565 }
566
567 void ThreadStackTrace::dump_stack_at_safepoint(int maxDepth) {
568 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
569
570 if (_thread->has_last_Java_frame()) {
571 RegisterMap reg_map(_thread);
572 vframe* start_vf = _thread->last_java_vframe(®_map);
573 int count = 0;
574 for (vframe* f = start_vf; f; f = f->sender() ) {
575 if (maxDepth >= 0 && count == maxDepth) {
576 // Skip frames if more than maxDepth
577 break;
578 }
579 if (f->is_java_frame()) {
580 javaVFrame* jvf = javaVFrame::cast(f);
581 add_stack_frame(jvf);
582 count++;
583 } else {
584 // Ignore non-Java frames
585 }
586 }
587 }
588
589 if (_with_locked_monitors) {
590 // Iterate inflated monitors and find monitors locked by this thread
591 // not found in the stack
592 InflatedMonitorsClosure imc(_thread, this);
593 ObjectSynchronizer::monitors_iterate(&imc);
594 }
595 }
596
597
598 bool ThreadStackTrace::is_owned_monitor_on_stack(oop object) {
599 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
600
601 bool found = false;
602 int num_frames = get_stack_depth();
603 for (int depth = 0; depth < num_frames; depth++) {
604 StackFrameInfo* frame = stack_frame_at(depth);
605 int len = frame->num_locked_monitors();
606 GrowableArray<oop>* locked_monitors = frame->locked_monitors();
607 for (int j = 0; j < len; j++) {
608 oop monitor = locked_monitors->at(j);
609 assert(monitor != NULL, "must be a Java object");
610 if (monitor == object) {
611 found = true;
612 break;
613 }
614 }
615 }
616 return found;
617 }
618
619 Handle ThreadStackTrace::allocate_fill_stack_trace_element_array(TRAPS) {
620 InstanceKlass* ik = SystemDictionary::StackTraceElement_klass();
621 assert(ik != NULL, "must be loaded in 1.4+");
622
623 // Allocate an array of java/lang/StackTraceElement object
624 objArrayOop ste = oopFactory::new_objArray(ik, _depth, CHECK_NH);
625 objArrayHandle backtrace(THREAD, ste);
626 for (int j = 0; j < _depth; j++) {
627 StackFrameInfo* frame = _frames->at(j);
628 methodHandle mh(THREAD, frame->method());
629 oop element = java_lang_StackTraceElement::create(mh, frame->bci(), CHECK_NH);
630 backtrace->obj_at_put(j, element);
631 }
632 return backtrace;
633 }
634
635 void ThreadStackTrace::add_stack_frame(javaVFrame* jvf) {
636 StackFrameInfo* frame = new StackFrameInfo(jvf, _with_locked_monitors);
637 _frames->append(frame);
638 _depth++;
639 }
640
641 void ThreadStackTrace::oops_do(OopClosure* f) {
642 int length = _frames->length();
643 for (int i = 0; i < length; i++) {
644 _frames->at(i)->oops_do(f);
645 }
646
647 length = (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0);
648 for (int j = 0; j < length; j++) {
649 f->do_oop((oop*) _jni_locked_monitors->adr_at(j));
650 }
651 }
652
653 void ThreadStackTrace::metadata_do(void f(Metadata*)) {
654 int length = _frames->length();
655 for (int i = 0; i < length; i++) {
656 _frames->at(i)->metadata_do(f);
657 }
658 }
659
660
661 ConcurrentLocksDump::~ConcurrentLocksDump() {
662 if (_retain_map_on_free) {
663 return;
664 }
665
666 for (ThreadConcurrentLocks* t = _map; t != NULL;) {
667 ThreadConcurrentLocks* tcl = t;
668 t = t->next();
669 delete tcl;
670 }
671 }
672
673 void ConcurrentLocksDump::dump_at_safepoint() {
674 // dump all locked concurrent locks
675 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
676
677 ResourceMark rm;
678
679 GrowableArray<oop>* aos_objects = new GrowableArray<oop>(INITIAL_ARRAY_SIZE);
680
681 // Find all instances of AbstractOwnableSynchronizer
682 HeapInspection::find_instances_at_safepoint(SystemDictionary::abstract_ownable_synchronizer_klass(),
683 aos_objects);
684 // Build a map of thread to its owned AQS locks
685 build_map(aos_objects);
686 }
687
688
689 // build a map of JavaThread to all its owned AbstractOwnableSynchronizer
690 void ConcurrentLocksDump::build_map(GrowableArray<oop>* aos_objects) {
691 int length = aos_objects->length();
692 for (int i = 0; i < length; i++) {
693 oop o = aos_objects->at(i);
694 oop owner_thread_obj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(o);
695 if (owner_thread_obj != NULL) {
696 // See comments in ThreadConcurrentLocks to see how this
697 // JavaThread* is protected.
698 JavaThread* thread = java_lang_Thread::thread(owner_thread_obj);
699 assert(o->is_instance(), "Must be an instanceOop");
700 add_lock(thread, (instanceOop) o);
701 }
702 }
703 }
704
705 void ConcurrentLocksDump::add_lock(JavaThread* thread, instanceOop o) {
706 ThreadConcurrentLocks* tcl = thread_concurrent_locks(thread);
707 if (tcl != NULL) {
708 tcl->add_lock(o);
709 return;
710 }
711
712 // First owned lock found for this thread
713 tcl = new ThreadConcurrentLocks(thread);
714 tcl->add_lock(o);
715 if (_map == NULL) {
716 _map = tcl;
717 } else {
718 _last->set_next(tcl);
719 }
720 _last = tcl;
721 }
722
723 ThreadConcurrentLocks* ConcurrentLocksDump::thread_concurrent_locks(JavaThread* thread) {
724 for (ThreadConcurrentLocks* tcl = _map; tcl != NULL; tcl = tcl->next()) {
725 if (tcl->java_thread() == thread) {
726 return tcl;
727 }
728 }
729 return NULL;
730 }
731
732 void ConcurrentLocksDump::print_locks_on(JavaThread* t, outputStream* st) {
733 st->print_cr(" Locked ownable synchronizers:");
734 ThreadConcurrentLocks* tcl = thread_concurrent_locks(t);
735 GrowableArray<instanceOop>* locks = (tcl != NULL ? tcl->owned_locks() : NULL);
736 if (locks == NULL || locks->is_empty()) {
737 st->print_cr("\t- None");
738 st->cr();
739 return;
740 }
741
742 for (int i = 0; i < locks->length(); i++) {
743 instanceOop obj = locks->at(i);
744 st->print_cr("\t- <" INTPTR_FORMAT "> (a %s)", p2i(obj), obj->klass()->external_name());
745 }
746 st->cr();
747 }
748
749 ThreadConcurrentLocks::ThreadConcurrentLocks(JavaThread* thread) {
750 _thread = thread;
751 _owned_locks = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<instanceOop>(INITIAL_ARRAY_SIZE, true);
752 _next = NULL;
753 }
754
755 ThreadConcurrentLocks::~ThreadConcurrentLocks() {
756 delete _owned_locks;
757 }
758
759 void ThreadConcurrentLocks::add_lock(instanceOop o) {
760 _owned_locks->append(o);
761 }
762
763 void ThreadConcurrentLocks::oops_do(OopClosure* f) {
764 int length = _owned_locks->length();
765 for (int i = 0; i < length; i++) {
766 f->do_oop((oop*) _owned_locks->adr_at(i));
767 }
768 }
769
770 ThreadStatistics::ThreadStatistics() {
771 _contended_enter_count = 0;
772 _monitor_wait_count = 0;
773 _sleep_count = 0;
774 _count_pending_reset = false;
775 _timer_pending_reset = false;
776 memset((void*) _perf_recursion_counts, 0, sizeof(_perf_recursion_counts));
777 }
778
779 ThreadSnapshot::ThreadSnapshot(ThreadsList * t_list, JavaThread* thread) {
780 _thread = thread;
781 _threadObj = thread->threadObj();
782 _stack_trace = NULL;
783 _concurrent_locks = NULL;
784 _next = NULL;
785
786 ThreadStatistics* stat = thread->get_thread_stat();
787 _contended_enter_ticks = stat->contended_enter_ticks();
788 _contended_enter_count = stat->contended_enter_count();
789 _monitor_wait_ticks = stat->monitor_wait_ticks();
790 _monitor_wait_count = stat->monitor_wait_count();
791 _sleep_ticks = stat->sleep_ticks();
792 _sleep_count = stat->sleep_count();
793
794 _blocker_object = NULL;
795 _blocker_object_owner = NULL;
796
797 _thread_status = java_lang_Thread::get_thread_status(_threadObj);
798 _is_ext_suspended = thread->is_being_ext_suspended();
799 _is_in_native = (thread->thread_state() == _thread_in_native);
800
801 if (_thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER ||
802 _thread_status == java_lang_Thread::IN_OBJECT_WAIT ||
803 _thread_status == java_lang_Thread::IN_OBJECT_WAIT_TIMED) {
804
805 Handle obj = ThreadService::get_current_contended_monitor(thread);
806 if (obj() == NULL) {
807 // monitor no longer exists; thread is not blocked
808 _thread_status = java_lang_Thread::RUNNABLE;
809 } else {
810 _blocker_object = obj();
811 JavaThread* owner = ObjectSynchronizer::get_lock_owner(t_list, obj);
812 if ((owner == NULL && _thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER)
813 || (owner != NULL && owner->is_attaching_via_jni())) {
814 // ownership information of the monitor is not available
815 // (may no longer be owned or releasing to some other thread)
816 // make this thread in RUNNABLE state.
817 // And when the owner thread is in attaching state, the java thread
818 // is not completely initialized. For example thread name and id
819 // and may not be set, so hide the attaching thread.
820 _thread_status = java_lang_Thread::RUNNABLE;
821 _blocker_object = NULL;
822 } else if (owner != NULL) {
823 _blocker_object_owner = owner->threadObj();
824 }
825 }
826 }
827
828 // Support for JSR-166 locks
829 if (JDK_Version::current().supports_thread_park_blocker() &&
830 (_thread_status == java_lang_Thread::PARKED ||
831 _thread_status == java_lang_Thread::PARKED_TIMED)) {
832
833 _blocker_object = thread->current_park_blocker();
834 if (_blocker_object != NULL && _blocker_object->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
835 _blocker_object_owner = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(_blocker_object);
836 }
837 }
838 }
839
840 ThreadSnapshot::~ThreadSnapshot() {
841 delete _stack_trace;
842 delete _concurrent_locks;
843 }
844
845 void ThreadSnapshot::dump_stack_at_safepoint(int max_depth, bool with_locked_monitors) {
846 _stack_trace = new ThreadStackTrace(_thread, with_locked_monitors);
847 _stack_trace->dump_stack_at_safepoint(max_depth);
848 }
849
850
851 void ThreadSnapshot::oops_do(OopClosure* f) {
852 f->do_oop(&_threadObj);
853 f->do_oop(&_blocker_object);
854 f->do_oop(&_blocker_object_owner);
855 if (_stack_trace != NULL) {
856 _stack_trace->oops_do(f);
857 }
858 if (_concurrent_locks != NULL) {
859 _concurrent_locks->oops_do(f);
860 }
861 }
862
863 void ThreadSnapshot::metadata_do(void f(Metadata*)) {
864 if (_stack_trace != NULL) {
865 _stack_trace->metadata_do(f);
866 }
867 }
868
869
870 DeadlockCycle::DeadlockCycle() {
871 _is_deadlock = false;
872 _threads = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<JavaThread*>(INITIAL_ARRAY_SIZE, true);
873 _next = NULL;
874 }
875
876 DeadlockCycle::~DeadlockCycle() {
877 delete _threads;
878 }
879
880 void DeadlockCycle::print_on_with(ThreadsList * t_list, outputStream* st) const {
881 st->cr();
882 st->print_cr("Found one Java-level deadlock:");
883 st->print("=============================");
884
885 JavaThread* currentThread;
886 ObjectMonitor* waitingToLockMonitor;
887 oop waitingToLockBlocker;
888 int len = _threads->length();
889 for (int i = 0; i < len; i++) {
890 currentThread = _threads->at(i);
891 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
892 waitingToLockBlocker = currentThread->current_park_blocker();
893 st->cr();
894 st->print_cr("\"%s\":", currentThread->get_thread_name());
895 const char* owner_desc = ",\n which is held by";
896 if (waitingToLockMonitor != NULL) {
897 st->print(" waiting to lock monitor " INTPTR_FORMAT, p2i(waitingToLockMonitor));
898 oop obj = (oop)waitingToLockMonitor->object();
899 if (obj != NULL) {
900 st->print(" (object " INTPTR_FORMAT ", a %s)", p2i(obj),
901 obj->klass()->external_name());
902
903 if (!currentThread->current_pending_monitor_is_from_java()) {
904 owner_desc = "\n in JNI, which is held by";
905 }
906 } else {
907 // No Java object associated - a JVMTI raw monitor
908 owner_desc = " (JVMTI raw monitor),\n which is held by";
909 }
910 currentThread = Threads::owning_thread_from_monitor_owner(t_list,
911 (address)waitingToLockMonitor->owner());
912 if (currentThread == NULL) {
913 // The deadlock was detected at a safepoint so the JavaThread
914 // that owns waitingToLockMonitor should be findable, but
915 // if it is not findable, then the previous currentThread is
916 // blocked permanently.
917 st->print("%s UNKNOWN_owner_addr=" PTR_FORMAT, owner_desc,
918 p2i(waitingToLockMonitor->owner()));
919 continue;
920 }
921 } else {
922 st->print(" waiting for ownable synchronizer " INTPTR_FORMAT ", (a %s)",
923 p2i(waitingToLockBlocker),
924 waitingToLockBlocker->klass()->external_name());
925 assert(waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass()),
926 "Must be an AbstractOwnableSynchronizer");
927 oop ownerObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
928 currentThread = java_lang_Thread::thread(ownerObj);
929 assert(currentThread != NULL, "AbstractOwnableSynchronizer owning thread is unexpectedly NULL");
930 }
931 st->print("%s \"%s\"", owner_desc, currentThread->get_thread_name());
932 }
933
934 st->cr();
935 st->cr();
936
937 // Print stack traces
938 bool oldJavaMonitorsInStackTrace = JavaMonitorsInStackTrace;
939 JavaMonitorsInStackTrace = true;
940 st->print_cr("Java stack information for the threads listed above:");
941 st->print_cr("===================================================");
942 for (int j = 0; j < len; j++) {
943 currentThread = _threads->at(j);
944 st->print_cr("\"%s\":", currentThread->get_thread_name());
945 currentThread->print_stack_on(st);
946 }
947 JavaMonitorsInStackTrace = oldJavaMonitorsInStackTrace;
948 }
949
950 ThreadsListEnumerator::ThreadsListEnumerator(Thread* cur_thread,
951 bool include_jvmti_agent_threads,
952 bool include_jni_attaching_threads) {
953 assert(cur_thread == Thread::current(), "Check current thread");
954
955 int init_size = ThreadService::get_live_thread_count();
956 _threads_array = new GrowableArray<instanceHandle>(init_size);
957
958 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
959 // skips JavaThreads in the process of exiting
960 // and also skips VM internal JavaThreads
961 // Threads in _thread_new or _thread_new_trans state are included.
962 // i.e. threads have been started but not yet running.
963 if (jt->threadObj() == NULL ||
964 jt->is_exiting() ||
965 !java_lang_Thread::is_alive(jt->threadObj()) ||
966 jt->is_hidden_from_external_view()) {
967 continue;
968 }
969
970 // skip agent threads
971 if (!include_jvmti_agent_threads && jt->is_jvmti_agent_thread()) {
972 continue;
973 }
974
975 // skip jni threads in the process of attaching
976 if (!include_jni_attaching_threads && jt->is_attaching_via_jni()) {
977 continue;
978 }
979
980 instanceHandle h(cur_thread, (instanceOop) jt->threadObj());
981 _threads_array->append(h);
982 }
983 }