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::_atomic_threads_count = 0;
61 volatile int ThreadService::_atomic_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 assert(Threads_lock->owned_by_self(), "must have threads lock");
106
107 // Do not count VM internal or JVMTI agent threads
108 if (thread->is_hidden_from_external_view() ||
109 thread->is_jvmti_agent_thread()) {
110 return;
111 }
112
113 _total_threads_count->inc();
114 _live_threads_count->inc();
115 Atomic::inc(&_atomic_threads_count);
116
117 if (_atomic_threads_count > _peak_threads_count->get_value()) {
118 _peak_threads_count->set_value(_atomic_threads_count);
119 }
120
121 if (daemon) {
122 _daemon_threads_count->inc();
123 Atomic::inc(&_atomic_daemon_threads_count);
124 }
125 }
126
127 void ThreadService::decrement_thread_counts(JavaThread* jt) {
128 Atomic::dec(&_atomic_threads_count);
129
130 oop threadObj = jt->threadObj();
131 if (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)) {
132 Atomic::dec(&_atomic_daemon_threads_count);
133 }
134 }
135
136 void ThreadService::remove_thread(JavaThread* thread, bool daemon) {
137 assert(Threads_lock->owned_by_self(), "must have threads lock");
138 if (thread->is_hidden_from_external_view() ||
139 thread->is_jvmti_agent_thread()) {
140 return;
141 }
142
143 assert(!thread->is_terminated(), "must not be terminated");
144 if (!thread->is_exiting()) {
145 // JavaThread::exit() skipped calling current_thread_exiting()
146 decrement_thread_counts(thread);
147 }
148
149 int daemon_count = _atomic_daemon_threads_count;
150 int count = _atomic_threads_count;
151
152 // Counts are incremented at the same time, but atomic counts are
153 // decremented earlier than perf counts.
154 assert(_live_threads_count->get_value() > count,
155 "thread count mismatch %d : %d",
156 (int)_live_threads_count->get_value(), count);
157
158 _live_threads_count->dec(1);
159 if (daemon) {
160 assert(_daemon_threads_count->get_value() > daemon_count,
161 "thread count mismatch %d : %d",
162 (int)_daemon_threads_count->get_value(), daemon_count);
163
164 _daemon_threads_count->dec(1);
165 }
166
167 // Counts are incremented at the same time, but atomic counts are
168 // decremented earlier than perf counts.
169 assert(_daemon_threads_count->get_value() >= daemon_count,
170 "thread count mismatch %d : %d",
171 (int)_daemon_threads_count->get_value(), daemon_count);
172 assert(_live_threads_count->get_value() >= count,
173 "thread count mismatch %d : %d",
174 (int)_live_threads_count->get_value(), count);
175 assert(_live_threads_count->get_value() > 0 ||
176 (_live_threads_count->get_value() == 0 && count == 0 &&
177 _daemon_threads_count->get_value() == 0 && daemon_count == 0),
178 "thread counts should reach 0 at the same time, live %d,%d daemon %d,%d",
179 (int)_live_threads_count->get_value(), count,
180 (int)_daemon_threads_count->get_value(), daemon_count);
181 assert(_daemon_threads_count->get_value() > 0 ||
182 (_daemon_threads_count->get_value() == 0 && daemon_count == 0),
183 "thread counts should reach 0 at the same time, daemon %d,%d",
184 (int)_daemon_threads_count->get_value(), daemon_count);
185 }
186
187 void ThreadService::current_thread_exiting(JavaThread* jt) {
188 if (jt->is_hidden_from_external_view() ||
189 jt->is_jvmti_agent_thread()) {
190 return;
191 }
192
193 assert(jt == JavaThread::current(), "Called by current thread");
194 assert(!jt->is_terminated() && jt->is_exiting(), "must be exiting");
195
196 decrement_thread_counts(jt);
197 }
198
199 // FIXME: JVMTI should call this function
200 Handle ThreadService::get_current_contended_monitor(JavaThread* thread) {
201 assert(thread != NULL, "should be non-NULL");
202 debug_only(Thread::check_for_dangling_thread_pointer(thread);)
203
204 ObjectMonitor *wait_obj = thread->current_waiting_monitor();
205
206 oop obj = NULL;
207 if (wait_obj != NULL) {
208 // thread is doing an Object.wait() call
209 obj = (oop) wait_obj->object();
210 assert(obj != NULL, "Object.wait() should have an object");
211 } else {
212 ObjectMonitor *enter_obj = thread->current_pending_monitor();
213 if (enter_obj != NULL) {
214 // thread is trying to enter() or raw_enter() an ObjectMonitor.
215 obj = (oop) enter_obj->object();
216 }
217 // If obj == NULL, then ObjectMonitor is raw which doesn't count.
218 }
219
220 Handle h(Thread::current(), obj);
221 return h;
222 }
223
224 bool ThreadService::set_thread_monitoring_contention(bool flag) {
225 MutexLocker m(Management_lock);
226
227 bool prev = _thread_monitoring_contention_enabled;
228 _thread_monitoring_contention_enabled = flag;
229
230 return prev;
231 }
232
233 bool ThreadService::set_thread_cpu_time_enabled(bool flag) {
234 MutexLocker m(Management_lock);
235
236 bool prev = _thread_cpu_time_enabled;
237 _thread_cpu_time_enabled = flag;
238
239 return prev;
240 }
241
242 bool ThreadService::set_thread_allocated_memory_enabled(bool flag) {
243 MutexLocker m(Management_lock);
244
245 bool prev = _thread_allocated_memory_enabled;
246 _thread_allocated_memory_enabled = flag;
247
248 return prev;
249 }
250
251 // GC support
252 void ThreadService::oops_do(OopClosure* f) {
253 for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) {
254 dump->oops_do(f);
255 }
256 }
257
258 void ThreadService::metadata_do(void f(Metadata*)) {
259 for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) {
260 dump->metadata_do(f);
261 }
262 }
263
264 void ThreadService::add_thread_dump(ThreadDumpResult* dump) {
265 MutexLocker ml(Management_lock);
266 if (_threaddump_list == NULL) {
267 _threaddump_list = dump;
268 } else {
269 dump->set_next(_threaddump_list);
270 _threaddump_list = dump;
271 }
272 }
273
274 void ThreadService::remove_thread_dump(ThreadDumpResult* dump) {
275 MutexLocker ml(Management_lock);
276
277 ThreadDumpResult* prev = NULL;
278 bool found = false;
279 for (ThreadDumpResult* d = _threaddump_list; d != NULL; prev = d, d = d->next()) {
280 if (d == dump) {
281 if (prev == NULL) {
282 _threaddump_list = dump->next();
283 } else {
284 prev->set_next(dump->next());
285 }
286 found = true;
287 break;
288 }
289 }
290 assert(found, "The threaddump result to be removed must exist.");
291 }
292
293 // Dump stack trace of threads specified in the given threads array.
294 // Returns StackTraceElement[][] each element is the stack trace of a thread in
295 // the corresponding entry in the given threads array
296 Handle ThreadService::dump_stack_traces(GrowableArray<instanceHandle>* threads,
297 int num_threads,
298 TRAPS) {
299 assert(num_threads > 0, "just checking");
300
301 ThreadDumpResult dump_result;
302 VM_ThreadDump op(&dump_result,
303 threads,
304 num_threads,
305 -1, /* entire stack */
306 false, /* with locked monitors */
307 false /* with locked synchronizers */);
308 VMThread::execute(&op);
309
310 // Allocate the resulting StackTraceElement[][] object
311
312 ResourceMark rm(THREAD);
313 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_StackTraceElement_array(), true, CHECK_NH);
314 ObjArrayKlass* ik = ObjArrayKlass::cast(k);
315 objArrayOop r = oopFactory::new_objArray(ik, num_threads, CHECK_NH);
316 objArrayHandle result_obj(THREAD, r);
317
318 int num_snapshots = dump_result.num_snapshots();
319 assert(num_snapshots == num_threads, "Must have num_threads thread snapshots");
320 assert(num_snapshots == 0 || dump_result.t_list_has_been_set(), "ThreadsList must have been set if we have a snapshot");
321 int i = 0;
322 for (ThreadSnapshot* ts = dump_result.snapshots(); ts != NULL; i++, ts = ts->next()) {
323 ThreadStackTrace* stacktrace = ts->get_stack_trace();
324 if (stacktrace == NULL) {
325 // No stack trace
326 result_obj->obj_at_put(i, NULL);
327 } else {
328 // Construct an array of java/lang/StackTraceElement object
329 Handle backtrace_h = stacktrace->allocate_fill_stack_trace_element_array(CHECK_NH);
330 result_obj->obj_at_put(i, backtrace_h());
331 }
332 }
333
334 return result_obj;
335 }
336
337 void ThreadService::reset_contention_count_stat(JavaThread* thread) {
338 ThreadStatistics* stat = thread->get_thread_stat();
339 if (stat != NULL) {
340 stat->reset_count_stat();
341 }
342 }
343
344 void ThreadService::reset_contention_time_stat(JavaThread* thread) {
345 ThreadStatistics* stat = thread->get_thread_stat();
346 if (stat != NULL) {
347 stat->reset_time_stat();
348 }
349 }
350
351 // Find deadlocks involving object monitors and concurrent locks if concurrent_locks is true
352 DeadlockCycle* ThreadService::find_deadlocks_at_safepoint(ThreadsList * t_list, bool concurrent_locks) {
353 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
354
355 // This code was modified from the original Threads::find_deadlocks code.
356 int globalDfn = 0, thisDfn;
357 ObjectMonitor* waitingToLockMonitor = NULL;
358 oop waitingToLockBlocker = NULL;
359 bool blocked_on_monitor = false;
360 JavaThread *currentThread, *previousThread;
361 int num_deadlocks = 0;
362
363 // Initialize the depth-first-number for each JavaThread.
364 JavaThreadIterator jti(t_list);
365 for (JavaThread* jt = jti.first(); jt != NULL; jt = jti.next()) {
366 jt->set_depth_first_number(-1);
367 }
368
369 DeadlockCycle* deadlocks = NULL;
370 DeadlockCycle* last = NULL;
371 DeadlockCycle* cycle = new DeadlockCycle();
372 for (JavaThread* jt = jti.first(); jt != NULL; jt = jti.next()) {
373 if (jt->depth_first_number() >= 0) {
374 // this thread was already visited
375 continue;
376 }
377
378 thisDfn = globalDfn;
379 jt->set_depth_first_number(globalDfn++);
380 previousThread = jt;
381 currentThread = jt;
382
383 cycle->reset();
384
385 // When there is a deadlock, all the monitors involved in the dependency
386 // cycle must be contended and heavyweight. So we only care about the
387 // heavyweight monitor a thread is waiting to lock.
388 waitingToLockMonitor = (ObjectMonitor*)jt->current_pending_monitor();
389 if (concurrent_locks) {
390 waitingToLockBlocker = jt->current_park_blocker();
391 }
392 while (waitingToLockMonitor != NULL || waitingToLockBlocker != NULL) {
393 cycle->add_thread(currentThread);
394 if (waitingToLockMonitor != NULL) {
395 address currentOwner = (address)waitingToLockMonitor->owner();
396 if (currentOwner != NULL) {
397 currentThread = Threads::owning_thread_from_monitor_owner(t_list,
398 currentOwner);
399 if (currentThread == NULL) {
400 // This function is called at a safepoint so the JavaThread
401 // that owns waitingToLockMonitor should be findable, but
402 // if it is not findable, then the previous currentThread is
403 // blocked permanently. We record this as a deadlock.
404 num_deadlocks++;
405
406 cycle->set_deadlock(true);
407
408 // add this cycle to the deadlocks list
409 if (deadlocks == NULL) {
410 deadlocks = cycle;
411 } else {
412 last->set_next(cycle);
413 }
414 last = cycle;
415 cycle = new DeadlockCycle();
416 break;
417 }
418 }
419 } else {
420 if (concurrent_locks) {
421 if (waitingToLockBlocker->is_a(SystemDictionary::java_util_concurrent_locks_AbstractOwnableSynchronizer_klass())) {
422 oop threadObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
423 // This JavaThread (if there is one) is protected by the
424 // ThreadsListSetter in VM_FindDeadlocks::doit().
425 currentThread = threadObj != NULL ? java_lang_Thread::thread(threadObj) : NULL;
426 } else {
427 currentThread = NULL;
428 }
429 }
430 }
431
432 if (currentThread == NULL) {
433 // No dependency on another thread
434 break;
435 }
436 if (currentThread->depth_first_number() < 0) {
437 // First visit to this thread
438 currentThread->set_depth_first_number(globalDfn++);
439 } else if (currentThread->depth_first_number() < thisDfn) {
440 // Thread already visited, and not on a (new) cycle
441 break;
442 } else if (currentThread == previousThread) {
443 // Self-loop, ignore
444 break;
445 } else {
446 // We have a (new) cycle
447 num_deadlocks++;
448
449 cycle->set_deadlock(true);
450
451 // add this cycle to the deadlocks list
452 if (deadlocks == NULL) {
453 deadlocks = cycle;
454 } else {
455 last->set_next(cycle);
456 }
457 last = cycle;
458 cycle = new DeadlockCycle();
459 break;
460 }
461 previousThread = currentThread;
462 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
463 if (concurrent_locks) {
464 waitingToLockBlocker = currentThread->current_park_blocker();
465 }
466 }
467
468 }
469 delete cycle;
470 return deadlocks;
471 }
472
473 ThreadDumpResult::ThreadDumpResult() : _num_threads(0), _num_snapshots(0), _snapshots(NULL), _last(NULL), _next(NULL), _setter() {
474
475 // Create a new ThreadDumpResult object and append to the list.
476 // If GC happens before this function returns, Method*
477 // in the stack trace will be visited.
478 ThreadService::add_thread_dump(this);
479 }
480
481 ThreadDumpResult::ThreadDumpResult(int num_threads) : _num_threads(num_threads), _num_snapshots(0), _snapshots(NULL), _last(NULL), _next(NULL), _setter() {
482 // Create a new ThreadDumpResult object and append to the list.
483 // If GC happens before this function returns, oops
484 // will be visited.
485 ThreadService::add_thread_dump(this);
486 }
487
488 ThreadDumpResult::~ThreadDumpResult() {
489 ThreadService::remove_thread_dump(this);
490
491 // free all the ThreadSnapshot objects created during
492 // the VM_ThreadDump operation
493 ThreadSnapshot* ts = _snapshots;
494 while (ts != NULL) {
495 ThreadSnapshot* p = ts;
496 ts = ts->next();
497 delete p;
498 }
499 }
500
501
502 void ThreadDumpResult::add_thread_snapshot(ThreadSnapshot* ts) {
503 assert(_num_threads == 0 || _num_snapshots < _num_threads,
504 "_num_snapshots must be less than _num_threads");
505 _num_snapshots++;
506 if (_snapshots == NULL) {
507 _snapshots = ts;
508 } else {
509 _last->set_next(ts);
510 }
511 _last = ts;
512 }
513
514 void ThreadDumpResult::oops_do(OopClosure* f) {
515 for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) {
516 ts->oops_do(f);
517 }
518 }
519
520 void ThreadDumpResult::metadata_do(void f(Metadata*)) {
521 for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) {
522 ts->metadata_do(f);
523 }
524 }
525
526 ThreadsList* ThreadDumpResult::t_list() {
527 return _setter.list();
528 }
529
530 StackFrameInfo::StackFrameInfo(javaVFrame* jvf, bool with_lock_info) {
531 _method = jvf->method();
532 _bci = jvf->bci();
533 _class_holder = _method->method_holder()->klass_holder();
534 _locked_monitors = NULL;
535 if (with_lock_info) {
536 ResourceMark rm;
537 GrowableArray<MonitorInfo*>* list = jvf->locked_monitors();
538 int length = list->length();
539 if (length > 0) {
540 _locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(length, true);
541 for (int i = 0; i < length; i++) {
542 MonitorInfo* monitor = list->at(i);
543 assert(monitor->owner() != NULL, "This monitor must have an owning object");
544 _locked_monitors->append(monitor->owner());
545 }
546 }
547 }
548 }
549
550 void StackFrameInfo::oops_do(OopClosure* f) {
551 if (_locked_monitors != NULL) {
552 int length = _locked_monitors->length();
553 for (int i = 0; i < length; i++) {
554 f->do_oop((oop*) _locked_monitors->adr_at(i));
555 }
556 }
557 f->do_oop(&_class_holder);
558 }
559
560 void StackFrameInfo::metadata_do(void f(Metadata*)) {
561 f(_method);
562 }
563
564 void StackFrameInfo::print_on(outputStream* st) const {
565 ResourceMark rm;
566 java_lang_Throwable::print_stack_element(st, method(), bci());
567 int len = (_locked_monitors != NULL ? _locked_monitors->length() : 0);
568 for (int i = 0; i < len; i++) {
569 oop o = _locked_monitors->at(i);
570 st->print_cr("\t- locked <" INTPTR_FORMAT "> (a %s)", p2i(o), o->klass()->external_name());
571 }
572
573 }
574
575 // Iterate through monitor cache to find JNI locked monitors
576 class InflatedMonitorsClosure: public MonitorClosure {
577 private:
578 ThreadStackTrace* _stack_trace;
579 Thread* _thread;
580 public:
581 InflatedMonitorsClosure(Thread* t, ThreadStackTrace* st) {
582 _thread = t;
583 _stack_trace = st;
584 }
585 void do_monitor(ObjectMonitor* mid) {
586 if (mid->owner() == _thread) {
587 oop object = (oop) mid->object();
588 if (!_stack_trace->is_owned_monitor_on_stack(object)) {
589 _stack_trace->add_jni_locked_monitor(object);
590 }
591 }
592 }
593 };
594
595 ThreadStackTrace::ThreadStackTrace(JavaThread* t, bool with_locked_monitors) {
596 _thread = t;
597 _frames = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<StackFrameInfo*>(INITIAL_ARRAY_SIZE, true);
598 _depth = 0;
599 _with_locked_monitors = with_locked_monitors;
600 if (_with_locked_monitors) {
601 _jni_locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(INITIAL_ARRAY_SIZE, true);
602 } else {
603 _jni_locked_monitors = NULL;
604 }
605 }
606
607 ThreadStackTrace::~ThreadStackTrace() {
608 for (int i = 0; i < _frames->length(); i++) {
609 delete _frames->at(i);
610 }
611 delete _frames;
612 if (_jni_locked_monitors != NULL) {
613 delete _jni_locked_monitors;
614 }
615 }
616
617 void ThreadStackTrace::dump_stack_at_safepoint(int maxDepth) {
618 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
619
620 if (_thread->has_last_Java_frame()) {
621 RegisterMap reg_map(_thread);
622 vframe* start_vf = _thread->last_java_vframe(®_map);
623 int count = 0;
624 for (vframe* f = start_vf; f; f = f->sender() ) {
625 if (maxDepth >= 0 && count == maxDepth) {
626 // Skip frames if more than maxDepth
627 break;
628 }
629 if (f->is_java_frame()) {
630 javaVFrame* jvf = javaVFrame::cast(f);
631 add_stack_frame(jvf);
632 count++;
633 } else {
634 // Ignore non-Java frames
635 }
636 }
637 }
638
639 if (_with_locked_monitors) {
640 // Iterate inflated monitors and find monitors locked by this thread
641 // not found in the stack
642 InflatedMonitorsClosure imc(_thread, this);
643 ObjectSynchronizer::monitors_iterate(&imc);
644 }
645 }
646
647
648 bool ThreadStackTrace::is_owned_monitor_on_stack(oop object) {
649 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
650
651 bool found = false;
652 int num_frames = get_stack_depth();
653 for (int depth = 0; depth < num_frames; depth++) {
654 StackFrameInfo* frame = stack_frame_at(depth);
655 int len = frame->num_locked_monitors();
656 GrowableArray<oop>* locked_monitors = frame->locked_monitors();
657 for (int j = 0; j < len; j++) {
658 oop monitor = locked_monitors->at(j);
659 assert(monitor != NULL, "must be a Java object");
660 if (oopDesc::equals(monitor, object)) {
661 found = true;
662 break;
663 }
664 }
665 }
666 return found;
667 }
668
669 Handle ThreadStackTrace::allocate_fill_stack_trace_element_array(TRAPS) {
670 InstanceKlass* ik = SystemDictionary::StackTraceElement_klass();
671 assert(ik != NULL, "must be loaded in 1.4+");
672
673 // Allocate an array of java/lang/StackTraceElement object
674 objArrayOop ste = oopFactory::new_objArray(ik, _depth, CHECK_NH);
675 objArrayHandle backtrace(THREAD, ste);
676 for (int j = 0; j < _depth; j++) {
677 StackFrameInfo* frame = _frames->at(j);
678 methodHandle mh(THREAD, frame->method());
679 oop element = java_lang_StackTraceElement::create(mh, frame->bci(), CHECK_NH);
680 backtrace->obj_at_put(j, element);
681 }
682 return backtrace;
683 }
684
685 void ThreadStackTrace::add_stack_frame(javaVFrame* jvf) {
686 StackFrameInfo* frame = new StackFrameInfo(jvf, _with_locked_monitors);
687 _frames->append(frame);
688 _depth++;
689 }
690
691 void ThreadStackTrace::oops_do(OopClosure* f) {
692 int length = _frames->length();
693 for (int i = 0; i < length; i++) {
694 _frames->at(i)->oops_do(f);
695 }
696
697 length = (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0);
698 for (int j = 0; j < length; j++) {
699 f->do_oop((oop*) _jni_locked_monitors->adr_at(j));
700 }
701 }
702
703 void ThreadStackTrace::metadata_do(void f(Metadata*)) {
704 int length = _frames->length();
705 for (int i = 0; i < length; i++) {
706 _frames->at(i)->metadata_do(f);
707 }
708 }
709
710
711 ConcurrentLocksDump::~ConcurrentLocksDump() {
712 if (_retain_map_on_free) {
713 return;
714 }
715
716 for (ThreadConcurrentLocks* t = _map; t != NULL;) {
717 ThreadConcurrentLocks* tcl = t;
718 t = t->next();
719 delete tcl;
720 }
721 }
722
723 void ConcurrentLocksDump::dump_at_safepoint() {
724 // dump all locked concurrent locks
725 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
726
727 GrowableArray<oop>* aos_objects = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(INITIAL_ARRAY_SIZE, true /* C_heap */);
728
729 // Find all instances of AbstractOwnableSynchronizer
730 HeapInspection::find_instances_at_safepoint(SystemDictionary::java_util_concurrent_locks_AbstractOwnableSynchronizer_klass(),
731 aos_objects);
732 // Build a map of thread to its owned AQS locks
733 build_map(aos_objects);
734
735 delete aos_objects;
736 }
737
738
739 // build a map of JavaThread to all its owned AbstractOwnableSynchronizer
740 void ConcurrentLocksDump::build_map(GrowableArray<oop>* aos_objects) {
741 int length = aos_objects->length();
742 for (int i = 0; i < length; i++) {
743 oop o = aos_objects->at(i);
744 oop owner_thread_obj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(o);
745 if (owner_thread_obj != NULL) {
746 // See comments in ThreadConcurrentLocks to see how this
747 // JavaThread* is protected.
748 JavaThread* thread = java_lang_Thread::thread(owner_thread_obj);
749 assert(o->is_instance(), "Must be an instanceOop");
750 add_lock(thread, (instanceOop) o);
751 }
752 }
753 }
754
755 void ConcurrentLocksDump::add_lock(JavaThread* thread, instanceOop o) {
756 ThreadConcurrentLocks* tcl = thread_concurrent_locks(thread);
757 if (tcl != NULL) {
758 tcl->add_lock(o);
759 return;
760 }
761
762 // First owned lock found for this thread
763 tcl = new ThreadConcurrentLocks(thread);
764 tcl->add_lock(o);
765 if (_map == NULL) {
766 _map = tcl;
767 } else {
768 _last->set_next(tcl);
769 }
770 _last = tcl;
771 }
772
773 ThreadConcurrentLocks* ConcurrentLocksDump::thread_concurrent_locks(JavaThread* thread) {
774 for (ThreadConcurrentLocks* tcl = _map; tcl != NULL; tcl = tcl->next()) {
775 if (tcl->java_thread() == thread) {
776 return tcl;
777 }
778 }
779 return NULL;
780 }
781
782 void ConcurrentLocksDump::print_locks_on(JavaThread* t, outputStream* st) {
783 st->print_cr(" Locked ownable synchronizers:");
784 ThreadConcurrentLocks* tcl = thread_concurrent_locks(t);
785 GrowableArray<instanceOop>* locks = (tcl != NULL ? tcl->owned_locks() : NULL);
786 if (locks == NULL || locks->is_empty()) {
787 st->print_cr("\t- None");
788 st->cr();
789 return;
790 }
791
792 for (int i = 0; i < locks->length(); i++) {
793 instanceOop obj = locks->at(i);
794 st->print_cr("\t- <" INTPTR_FORMAT "> (a %s)", p2i(obj), obj->klass()->external_name());
795 }
796 st->cr();
797 }
798
799 ThreadConcurrentLocks::ThreadConcurrentLocks(JavaThread* thread) {
800 _thread = thread;
801 _owned_locks = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<instanceOop>(INITIAL_ARRAY_SIZE, true);
802 _next = NULL;
803 }
804
805 ThreadConcurrentLocks::~ThreadConcurrentLocks() {
806 delete _owned_locks;
807 }
808
809 void ThreadConcurrentLocks::add_lock(instanceOop o) {
810 _owned_locks->append(o);
811 }
812
813 void ThreadConcurrentLocks::oops_do(OopClosure* f) {
814 int length = _owned_locks->length();
815 for (int i = 0; i < length; i++) {
816 f->do_oop((oop*) _owned_locks->adr_at(i));
817 }
818 }
819
820 ThreadStatistics::ThreadStatistics() {
821 _contended_enter_count = 0;
822 _monitor_wait_count = 0;
823 _sleep_count = 0;
824 _count_pending_reset = false;
825 _timer_pending_reset = false;
826 memset((void*) _perf_recursion_counts, 0, sizeof(_perf_recursion_counts));
827 }
828
829 ThreadSnapshot::ThreadSnapshot(ThreadsList * t_list, JavaThread* thread) {
830 _thread = thread;
831 _threadObj = thread->threadObj();
832 _stack_trace = NULL;
833 _concurrent_locks = NULL;
834 _next = NULL;
835
836 ThreadStatistics* stat = thread->get_thread_stat();
837 _contended_enter_ticks = stat->contended_enter_ticks();
838 _contended_enter_count = stat->contended_enter_count();
839 _monitor_wait_ticks = stat->monitor_wait_ticks();
840 _monitor_wait_count = stat->monitor_wait_count();
841 _sleep_ticks = stat->sleep_ticks();
842 _sleep_count = stat->sleep_count();
843
844 _blocker_object = NULL;
845 _blocker_object_owner = NULL;
846
847 _thread_status = java_lang_Thread::get_thread_status(_threadObj);
848 _is_ext_suspended = thread->is_being_ext_suspended();
849 _is_in_native = (thread->thread_state() == _thread_in_native);
850
851 if (_thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER ||
852 _thread_status == java_lang_Thread::IN_OBJECT_WAIT ||
853 _thread_status == java_lang_Thread::IN_OBJECT_WAIT_TIMED) {
854
855 Handle obj = ThreadService::get_current_contended_monitor(thread);
856 if (obj() == NULL) {
857 // monitor no longer exists; thread is not blocked
858 _thread_status = java_lang_Thread::RUNNABLE;
859 } else {
860 _blocker_object = obj();
861 JavaThread* owner = ObjectSynchronizer::get_lock_owner(t_list, obj);
862 if ((owner == NULL && _thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER)
863 || (owner != NULL && owner->is_attaching_via_jni())) {
864 // ownership information of the monitor is not available
865 // (may no longer be owned or releasing to some other thread)
866 // make this thread in RUNNABLE state.
867 // And when the owner thread is in attaching state, the java thread
868 // is not completely initialized. For example thread name and id
869 // and may not be set, so hide the attaching thread.
870 _thread_status = java_lang_Thread::RUNNABLE;
871 _blocker_object = NULL;
872 } else if (owner != NULL) {
873 _blocker_object_owner = owner->threadObj();
874 }
875 }
876 }
877
878 // Support for JSR-166 locks
879 if (JDK_Version::current().supports_thread_park_blocker() &&
880 (_thread_status == java_lang_Thread::PARKED ||
881 _thread_status == java_lang_Thread::PARKED_TIMED)) {
882
883 _blocker_object = thread->current_park_blocker();
884 if (_blocker_object != NULL && _blocker_object->is_a(SystemDictionary::java_util_concurrent_locks_AbstractOwnableSynchronizer_klass())) {
885 _blocker_object_owner = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(_blocker_object);
886 }
887 }
888 }
889
890 ThreadSnapshot::~ThreadSnapshot() {
891 delete _stack_trace;
892 delete _concurrent_locks;
893 }
894
895 void ThreadSnapshot::dump_stack_at_safepoint(int max_depth, bool with_locked_monitors) {
896 _stack_trace = new ThreadStackTrace(_thread, with_locked_monitors);
897 _stack_trace->dump_stack_at_safepoint(max_depth);
898 }
899
900
901 void ThreadSnapshot::oops_do(OopClosure* f) {
902 f->do_oop(&_threadObj);
903 f->do_oop(&_blocker_object);
904 f->do_oop(&_blocker_object_owner);
905 if (_stack_trace != NULL) {
906 _stack_trace->oops_do(f);
907 }
908 if (_concurrent_locks != NULL) {
909 _concurrent_locks->oops_do(f);
910 }
911 }
912
913 void ThreadSnapshot::metadata_do(void f(Metadata*)) {
914 if (_stack_trace != NULL) {
915 _stack_trace->metadata_do(f);
916 }
917 }
918
919
920 DeadlockCycle::DeadlockCycle() {
921 _is_deadlock = false;
922 _threads = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<JavaThread*>(INITIAL_ARRAY_SIZE, true);
923 _next = NULL;
924 }
925
926 DeadlockCycle::~DeadlockCycle() {
927 delete _threads;
928 }
929
930 void DeadlockCycle::print_on_with(ThreadsList * t_list, outputStream* st) const {
931 st->cr();
932 st->print_cr("Found one Java-level deadlock:");
933 st->print("=============================");
934
935 JavaThread* currentThread;
936 ObjectMonitor* waitingToLockMonitor;
937 oop waitingToLockBlocker;
938 int len = _threads->length();
939 for (int i = 0; i < len; i++) {
940 currentThread = _threads->at(i);
941 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor();
942 waitingToLockBlocker = currentThread->current_park_blocker();
943 st->cr();
944 st->print_cr("\"%s\":", currentThread->get_thread_name());
945 const char* owner_desc = ",\n which is held by";
946 if (waitingToLockMonitor != NULL) {
947 st->print(" waiting to lock monitor " INTPTR_FORMAT, p2i(waitingToLockMonitor));
948 oop obj = (oop)waitingToLockMonitor->object();
949 if (obj != NULL) {
950 st->print(" (object " INTPTR_FORMAT ", a %s)", p2i(obj),
951 obj->klass()->external_name());
952
953 if (!currentThread->current_pending_monitor_is_from_java()) {
954 owner_desc = "\n in JNI, which is held by";
955 }
956 } else {
957 // No Java object associated - a JVMTI raw monitor
958 owner_desc = " (JVMTI raw monitor),\n which is held by";
959 }
960 currentThread = Threads::owning_thread_from_monitor_owner(t_list,
961 (address)waitingToLockMonitor->owner());
962 if (currentThread == NULL) {
963 // The deadlock was detected at a safepoint so the JavaThread
964 // that owns waitingToLockMonitor should be findable, but
965 // if it is not findable, then the previous currentThread is
966 // blocked permanently.
967 st->print("%s UNKNOWN_owner_addr=" PTR_FORMAT, owner_desc,
968 p2i(waitingToLockMonitor->owner()));
969 continue;
970 }
971 } else {
972 st->print(" waiting for ownable synchronizer " INTPTR_FORMAT ", (a %s)",
973 p2i(waitingToLockBlocker),
974 waitingToLockBlocker->klass()->external_name());
975 assert(waitingToLockBlocker->is_a(SystemDictionary::java_util_concurrent_locks_AbstractOwnableSynchronizer_klass()),
976 "Must be an AbstractOwnableSynchronizer");
977 oop ownerObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
978 currentThread = java_lang_Thread::thread(ownerObj);
979 assert(currentThread != NULL, "AbstractOwnableSynchronizer owning thread is unexpectedly NULL");
980 }
981 st->print("%s \"%s\"", owner_desc, currentThread->get_thread_name());
982 }
983
984 st->cr();
985 st->cr();
986
987 // Print stack traces
988 bool oldJavaMonitorsInStackTrace = JavaMonitorsInStackTrace;
989 JavaMonitorsInStackTrace = true;
990 st->print_cr("Java stack information for the threads listed above:");
991 st->print_cr("===================================================");
992 for (int j = 0; j < len; j++) {
993 currentThread = _threads->at(j);
994 st->print_cr("\"%s\":", currentThread->get_thread_name());
995 currentThread->print_stack_on(st);
996 }
997 JavaMonitorsInStackTrace = oldJavaMonitorsInStackTrace;
998 }
999
1000 ThreadsListEnumerator::ThreadsListEnumerator(Thread* cur_thread,
1001 bool include_jvmti_agent_threads,
1002 bool include_jni_attaching_threads) {
1003 assert(cur_thread == Thread::current(), "Check current thread");
1004
1005 int init_size = ThreadService::get_live_thread_count();
1006 _threads_array = new GrowableArray<instanceHandle>(init_size);
1007
1008 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
1009 // skips JavaThreads in the process of exiting
1010 // and also skips VM internal JavaThreads
1011 // Threads in _thread_new or _thread_new_trans state are included.
1012 // i.e. threads have been started but not yet running.
1013 if (jt->threadObj() == NULL ||
1014 jt->is_exiting() ||
1015 !java_lang_Thread::is_alive(jt->threadObj()) ||
1016 jt->is_hidden_from_external_view()) {
1017 continue;
1018 }
1019
1020 // skip agent threads
1021 if (!include_jvmti_agent_threads && jt->is_jvmti_agent_thread()) {
1022 continue;
1023 }
1024
1025 // skip jni threads in the process of attaching
1026 if (!include_jni_attaching_threads && jt->is_attaching_via_jni()) {
1027 continue;
1028 }
1029
1030 instanceHandle h(cur_thread, (instanceOop) jt->threadObj());
1031 _threads_array->append(h);
1032 }
1033 }