Thu, 12 Mar 2009 18:16:36 -0700
Merge
1 /*
2 * Copyright 2003-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 class OopClosure;
26 class ThreadDumpResult;
27 class ThreadStackTrace;
28 class ThreadSnapshot;
29 class StackFrameInfo;
30 class ThreadConcurrentLocks;
31 class DeadlockCycle;
33 // VM monitoring and management support for the thread and
34 // synchronization subsystem
35 //
36 // Thread contention monitoring is disabled by default.
37 // When enabled, the VM will begin measuring the accumulated
38 // elapsed time a thread blocked on synchronization.
39 //
40 class ThreadService : public AllStatic {
41 private:
42 // These counters could be moved to Threads class
43 static PerfCounter* _total_threads_count;
44 static PerfVariable* _live_threads_count;
45 static PerfVariable* _peak_threads_count;
46 static PerfVariable* _daemon_threads_count;
48 // These 2 counters are atomically incremented once the thread is exiting.
49 // They will be atomically decremented when ThreadService::remove_thread is called.
50 static volatile int _exiting_threads_count;
51 static volatile int _exiting_daemon_threads_count;
53 static bool _thread_monitoring_contention_enabled;
54 static bool _thread_cpu_time_enabled;
56 // Need to keep the list of thread dump result that
57 // keep references to methodOop since thread dump can be
58 // requested by multiple threads concurrently.
59 static ThreadDumpResult* _threaddump_list;
61 public:
62 static void init();
63 static void add_thread(JavaThread* thread, bool daemon);
64 static void remove_thread(JavaThread* thread, bool daemon);
65 static void current_thread_exiting(JavaThread* jt);
67 static bool set_thread_monitoring_contention(bool flag);
68 static bool is_thread_monitoring_contention() { return _thread_monitoring_contention_enabled; }
70 static bool set_thread_cpu_time_enabled(bool flag);
71 static bool is_thread_cpu_time_enabled() { return _thread_cpu_time_enabled; }
73 static jlong get_total_thread_count() { return _total_threads_count->get_value(); }
74 static jlong get_peak_thread_count() { return _peak_threads_count->get_value(); }
75 static jlong get_live_thread_count() { return _live_threads_count->get_value() - _exiting_threads_count; }
76 static jlong get_daemon_thread_count() { return _daemon_threads_count->get_value() - _exiting_daemon_threads_count; }
78 static int exiting_threads_count() { return _exiting_threads_count; }
79 static int exiting_daemon_threads_count() { return _exiting_daemon_threads_count; }
81 // Support for thread dump
82 static void add_thread_dump(ThreadDumpResult* dump);
83 static void remove_thread_dump(ThreadDumpResult* dump);
85 static Handle get_current_contended_monitor(JavaThread* thread);
87 // This function is called by JVM_DumpThreads.
88 static Handle dump_stack_traces(GrowableArray<instanceHandle>* threads,
89 int num_threads, TRAPS);
91 static void reset_peak_thread_count();
92 static void reset_contention_count_stat(JavaThread* thread);
93 static void reset_contention_time_stat(JavaThread* thread);
95 static DeadlockCycle* find_deadlocks_at_safepoint(bool object_monitors_only);
97 // GC support
98 static void oops_do(OopClosure* f);
99 };
101 // Per-thread Statistics for synchronization
102 class ThreadStatistics : public CHeapObj {
103 private:
104 // The following contention statistics are only updated by
105 // the thread owning these statistics when contention occurs.
107 jlong _contended_enter_count;
108 elapsedTimer _contended_enter_timer;
109 jlong _monitor_wait_count;
110 elapsedTimer _monitor_wait_timer;
111 jlong _sleep_count;
112 elapsedTimer _sleep_timer;
115 // These two reset flags are set to true when another thread
116 // requests to reset the statistics. The actual statistics
117 // are reset when the thread contention occurs and attempts
118 // to update the statistics.
119 bool _count_pending_reset;
120 bool _timer_pending_reset;
122 // Keep accurate times for potentially recursive class operations
123 int _class_init_recursion_count;
124 int _class_verify_recursion_count;
125 int _class_link_recursion_count;
127 // utility functions
128 void check_and_reset_count() {
129 if (!_count_pending_reset) return;
130 _contended_enter_count = 0;
131 _monitor_wait_count = 0;
132 _sleep_count = 0;
133 _count_pending_reset = 0;
134 }
135 void check_and_reset_timer() {
136 if (!_timer_pending_reset) return;
137 _contended_enter_timer.reset();
138 _monitor_wait_timer.reset();
139 _sleep_timer.reset();
140 _timer_pending_reset = 0;
141 }
143 public:
144 ThreadStatistics();
146 jlong contended_enter_count() { return (_count_pending_reset ? 0 : _contended_enter_count); }
147 jlong contended_enter_ticks() { return (_timer_pending_reset ? 0 : _contended_enter_timer.active_ticks()); }
148 jlong monitor_wait_count() { return (_count_pending_reset ? 0 : _monitor_wait_count); }
149 jlong monitor_wait_ticks() { return (_timer_pending_reset ? 0 : _monitor_wait_timer.active_ticks()); }
150 jlong sleep_count() { return (_count_pending_reset ? 0 : _sleep_count); }
151 jlong sleep_ticks() { return (_timer_pending_reset ? 0 : _sleep_timer.active_ticks()); }
153 void monitor_wait() { check_and_reset_count(); _monitor_wait_count++; }
154 void monitor_wait_begin() { check_and_reset_timer(); _monitor_wait_timer.start(); }
155 void monitor_wait_end() { _monitor_wait_timer.stop(); check_and_reset_timer(); }
157 void thread_sleep() { check_and_reset_count(); _sleep_count++; }
158 void thread_sleep_begin() { check_and_reset_timer(); _sleep_timer.start(); }
159 void thread_sleep_end() { _sleep_timer.stop(); check_and_reset_timer(); }
161 void contended_enter() { check_and_reset_count(); _contended_enter_count++; }
162 void contended_enter_begin() { check_and_reset_timer(); _contended_enter_timer.start(); }
163 void contended_enter_end() { _contended_enter_timer.stop(); check_and_reset_timer(); }
165 void reset_count_stat() { _count_pending_reset = true; }
166 void reset_time_stat() { _timer_pending_reset = true; }
168 int* class_init_recursion_count_addr() { return &_class_init_recursion_count; }
169 int* class_verify_recursion_count_addr() { return &_class_verify_recursion_count; }
170 int* class_link_recursion_count_addr() { return &_class_link_recursion_count; }
171 };
173 // Thread snapshot to represent the thread state and statistics
174 class ThreadSnapshot : public CHeapObj {
175 private:
176 JavaThread* _thread;
177 oop _threadObj;
178 java_lang_Thread::ThreadStatus _thread_status;
180 bool _is_ext_suspended;
181 bool _is_in_native;
183 jlong _contended_enter_ticks;
184 jlong _contended_enter_count;
185 jlong _monitor_wait_ticks;
186 jlong _monitor_wait_count;
187 jlong _sleep_ticks;
188 jlong _sleep_count;
189 oop _blocker_object;
190 oop _blocker_object_owner;
192 ThreadStackTrace* _stack_trace;
193 ThreadConcurrentLocks* _concurrent_locks;
194 ThreadSnapshot* _next;
196 public:
197 // Dummy snapshot
198 ThreadSnapshot() : _thread(NULL), _threadObj(NULL), _stack_trace(NULL), _concurrent_locks(NULL), _next(NULL),
199 _blocker_object(NULL), _blocker_object_owner(NULL) {};
200 ThreadSnapshot(JavaThread* thread);
201 ~ThreadSnapshot();
203 java_lang_Thread::ThreadStatus thread_status() { return _thread_status; }
205 oop threadObj() const { return _threadObj; }
207 void set_next(ThreadSnapshot* n) { _next = n; }
209 bool is_ext_suspended() { return _is_ext_suspended; }
210 bool is_in_native() { return _is_in_native; }
212 jlong contended_enter_count() { return _contended_enter_count; }
213 jlong contended_enter_ticks() { return _contended_enter_ticks; }
214 jlong monitor_wait_count() { return _monitor_wait_count; }
215 jlong monitor_wait_ticks() { return _monitor_wait_ticks; }
216 jlong sleep_count() { return _sleep_count; }
217 jlong sleep_ticks() { return _sleep_ticks; }
220 oop blocker_object() { return _blocker_object; }
221 oop blocker_object_owner() { return _blocker_object_owner; }
223 ThreadSnapshot* next() const { return _next; }
224 ThreadStackTrace* get_stack_trace() { return _stack_trace; }
225 ThreadConcurrentLocks* get_concurrent_locks() { return _concurrent_locks; }
227 void dump_stack_at_safepoint(int max_depth, bool with_locked_monitors);
228 void set_concurrent_locks(ThreadConcurrentLocks* l) { _concurrent_locks = l; }
229 void oops_do(OopClosure* f);
230 };
232 class ThreadStackTrace : public CHeapObj {
233 private:
234 JavaThread* _thread;
235 int _depth; // number of stack frames added
236 bool _with_locked_monitors;
237 GrowableArray<StackFrameInfo*>* _frames;
238 GrowableArray<oop>* _jni_locked_monitors;
240 public:
242 ThreadStackTrace(JavaThread* thread, bool with_locked_monitors);
243 ~ThreadStackTrace();
245 JavaThread* thread() { return _thread; }
246 StackFrameInfo* stack_frame_at(int i) { return _frames->at(i); }
247 int get_stack_depth() { return _depth; }
249 void add_stack_frame(javaVFrame* jvf);
250 void dump_stack_at_safepoint(int max_depth);
251 Handle allocate_fill_stack_trace_element_array(TRAPS);
252 void oops_do(OopClosure* f);
253 GrowableArray<oop>* jni_locked_monitors() { return _jni_locked_monitors; }
254 int num_jni_locked_monitors() { return (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0); }
256 bool is_owned_monitor_on_stack(oop object);
257 void add_jni_locked_monitor(oop object) { _jni_locked_monitors->append(object); }
258 };
260 // StackFrameInfo for keeping methodOop and bci during
261 // stack walking for later construction of StackTraceElement[]
262 // Java instances
263 class StackFrameInfo : public CHeapObj {
264 private:
265 methodOop _method;
266 int _bci;
267 GrowableArray<oop>* _locked_monitors; // list of object monitors locked by this frame
269 public:
271 StackFrameInfo(javaVFrame* jvf, bool with_locked_monitors);
272 ~StackFrameInfo() {
273 if (_locked_monitors != NULL) {
274 delete _locked_monitors;
275 }
276 };
277 methodOop method() const { return _method; }
278 int bci() const { return _bci; }
279 void oops_do(OopClosure* f);
281 int num_locked_monitors() { return (_locked_monitors != NULL ? _locked_monitors->length() : 0); }
282 GrowableArray<oop>* locked_monitors() { return _locked_monitors; }
284 void print_on(outputStream* st) const;
285 };
287 class ThreadConcurrentLocks : public CHeapObj {
288 private:
289 GrowableArray<instanceOop>* _owned_locks;
290 ThreadConcurrentLocks* _next;
291 JavaThread* _thread;
292 public:
293 ThreadConcurrentLocks(JavaThread* thread);
294 ~ThreadConcurrentLocks();
296 void add_lock(instanceOop o);
297 void set_next(ThreadConcurrentLocks* n) { _next = n; }
298 ThreadConcurrentLocks* next() { return _next; }
299 JavaThread* java_thread() { return _thread; }
300 GrowableArray<instanceOop>* owned_locks() { return _owned_locks; }
301 void oops_do(OopClosure* f);
302 };
304 class ConcurrentLocksDump : public StackObj {
305 private:
306 ThreadConcurrentLocks* _map;
307 ThreadConcurrentLocks* _last; // Last ThreadConcurrentLocks in the map
308 bool _retain_map_on_free;
310 void build_map(GrowableArray<oop>* aos_objects);
311 void add_lock(JavaThread* thread, instanceOop o);
313 public:
314 ConcurrentLocksDump(bool retain_map_on_free) : _map(NULL), _last(NULL), _retain_map_on_free(retain_map_on_free) {};
315 ConcurrentLocksDump() : _map(NULL), _last(NULL), _retain_map_on_free(false) {};
316 ~ConcurrentLocksDump();
318 void dump_at_safepoint();
319 ThreadConcurrentLocks* thread_concurrent_locks(JavaThread* thread);
320 void print_locks_on(JavaThread* t, outputStream* st);
321 };
323 class ThreadDumpResult : public StackObj {
324 private:
325 int _num_threads;
326 int _num_snapshots;
327 ThreadSnapshot* _snapshots;
328 ThreadSnapshot* _last;
329 ThreadDumpResult* _next;
330 public:
331 ThreadDumpResult();
332 ThreadDumpResult(int num_threads);
333 ~ThreadDumpResult();
335 void add_thread_snapshot(ThreadSnapshot* ts);
336 void set_next(ThreadDumpResult* next) { _next = next; }
337 ThreadDumpResult* next() { return _next; }
338 int num_threads() { return _num_threads; }
339 int num_snapshots() { return _num_snapshots; }
340 ThreadSnapshot* snapshots() { return _snapshots; }
341 void oops_do(OopClosure* f);
342 };
344 class DeadlockCycle : public CHeapObj {
345 private:
346 bool _is_deadlock;
347 GrowableArray<JavaThread*>* _threads;
348 DeadlockCycle* _next;
349 public:
350 DeadlockCycle();
351 ~DeadlockCycle();
353 DeadlockCycle* next() { return _next; }
354 void set_next(DeadlockCycle* d) { _next = d; }
355 void add_thread(JavaThread* t) { _threads->append(t); }
356 void reset() { _is_deadlock = false; _threads->clear(); }
357 void set_deadlock(bool value) { _is_deadlock = value; }
358 bool is_deadlock() { return _is_deadlock; }
359 int num_threads() { return _threads->length(); }
360 GrowableArray<JavaThread*>* threads() { return _threads; }
361 void print_on(outputStream* st) const;
362 };
364 // Utility class to get list of java threads.
365 class ThreadsListEnumerator : public StackObj {
366 private:
367 GrowableArray<instanceHandle>* _threads_array;
368 public:
369 ThreadsListEnumerator(Thread* cur_thread,
370 bool include_jvmti_agent_threads = false,
371 bool include_jni_attaching_threads = true);
372 int num_threads() { return _threads_array->length(); }
373 instanceHandle get_threadObj(int index) { return _threads_array->at(index); }
374 };
377 // abstract utility class to set new thread states, and restore previous after the block exits
378 class JavaThreadStatusChanger : public StackObj {
379 private:
380 java_lang_Thread::ThreadStatus _old_state;
381 JavaThread* _java_thread;
382 bool _is_alive;
384 void save_old_state(JavaThread* java_thread) {
385 _java_thread = java_thread;
386 _is_alive = is_alive(java_thread);
387 if (is_alive()) {
388 _old_state = java_lang_Thread::get_thread_status(_java_thread->threadObj());
389 }
390 }
392 public:
393 static void set_thread_status(JavaThread* java_thread,
394 java_lang_Thread::ThreadStatus state) {
395 java_lang_Thread::set_thread_status(java_thread->threadObj(), state);
396 }
398 void set_thread_status(java_lang_Thread::ThreadStatus state) {
399 if (is_alive()) {
400 set_thread_status(_java_thread, state);
401 }
402 }
404 JavaThreadStatusChanger(JavaThread* java_thread,
405 java_lang_Thread::ThreadStatus state) {
406 save_old_state(java_thread);
407 set_thread_status(state);
408 }
410 JavaThreadStatusChanger(JavaThread* java_thread) {
411 save_old_state(java_thread);
412 }
414 ~JavaThreadStatusChanger() {
415 set_thread_status(_old_state);
416 }
418 static bool is_alive(JavaThread* java_thread) {
419 return java_thread != NULL && java_thread->threadObj() != NULL;
420 }
422 bool is_alive() {
423 return _is_alive;
424 }
425 };
427 // Change status to waiting on an object (timed or indefinite)
428 class JavaThreadInObjectWaitState : public JavaThreadStatusChanger {
429 private:
430 ThreadStatistics* _stat;
431 bool _active;
433 public:
434 JavaThreadInObjectWaitState(JavaThread *java_thread, bool timed) :
435 JavaThreadStatusChanger(java_thread,
436 timed ? java_lang_Thread::IN_OBJECT_WAIT_TIMED : java_lang_Thread::IN_OBJECT_WAIT) {
437 if (is_alive()) {
438 _stat = java_thread->get_thread_stat();
439 _active = ThreadService::is_thread_monitoring_contention();
440 _stat->monitor_wait();
441 if (_active) {
442 _stat->monitor_wait_begin();
443 }
444 } else {
445 _active = false;
446 }
447 }
449 ~JavaThreadInObjectWaitState() {
450 if (_active) {
451 _stat->monitor_wait_end();
452 }
453 }
454 };
456 // Change status to parked (timed or indefinite)
457 class JavaThreadParkedState : public JavaThreadStatusChanger {
458 private:
459 ThreadStatistics* _stat;
460 bool _active;
462 public:
463 JavaThreadParkedState(JavaThread *java_thread, bool timed) :
464 JavaThreadStatusChanger(java_thread,
465 timed ? java_lang_Thread::PARKED_TIMED : java_lang_Thread::PARKED) {
466 if (is_alive()) {
467 _stat = java_thread->get_thread_stat();
468 _active = ThreadService::is_thread_monitoring_contention();
469 _stat->monitor_wait();
470 if (_active) {
471 _stat->monitor_wait_begin();
472 }
473 } else {
474 _active = false;
475 }
476 }
478 ~JavaThreadParkedState() {
479 if (_active) {
480 _stat->monitor_wait_end();
481 }
482 }
483 };
485 // Change status to blocked on (re-)entering a synchronization block
486 class JavaThreadBlockedOnMonitorEnterState : public JavaThreadStatusChanger {
487 private:
488 ThreadStatistics* _stat;
489 bool _active;
491 static bool contended_enter_begin(JavaThread *java_thread) {
492 set_thread_status(java_thread, java_lang_Thread::BLOCKED_ON_MONITOR_ENTER);
493 ThreadStatistics* stat = java_thread->get_thread_stat();
494 stat->contended_enter();
495 bool active = ThreadService::is_thread_monitoring_contention();
496 if (active) {
497 stat->contended_enter_begin();
498 }
499 return active;
500 }
502 public:
503 // java_thread is waiting thread being blocked on monitor reenter.
504 // Current thread is the notifying thread which holds the monitor.
505 static bool wait_reenter_begin(JavaThread *java_thread, ObjectMonitor *obj_m) {
506 assert((java_thread != NULL), "Java thread should not be null here");
507 bool active = false;
508 if (is_alive(java_thread) && ServiceUtil::visible_oop((oop)obj_m->object())) {
509 active = contended_enter_begin(java_thread);
510 }
511 return active;
512 }
514 static void wait_reenter_end(JavaThread *java_thread, bool active) {
515 if (active) {
516 java_thread->get_thread_stat()->contended_enter_end();
517 }
518 set_thread_status(java_thread, java_lang_Thread::RUNNABLE);
519 }
521 JavaThreadBlockedOnMonitorEnterState(JavaThread *java_thread, ObjectMonitor *obj_m) :
522 JavaThreadStatusChanger(java_thread) {
523 assert((java_thread != NULL), "Java thread should not be null here");
524 // Change thread status and collect contended enter stats for monitor contended
525 // enter done for external java world objects and it is contended. All other cases
526 // like for vm internal objects and for external objects which are not contended
527 // thread status is not changed and contended enter stat is not collected.
528 _active = false;
529 if (is_alive() && ServiceUtil::visible_oop((oop)obj_m->object()) && obj_m->contentions() > 0) {
530 _stat = java_thread->get_thread_stat();
531 _active = contended_enter_begin(java_thread);
532 }
533 }
535 ~JavaThreadBlockedOnMonitorEnterState() {
536 if (_active) {
537 _stat->contended_enter_end();
538 }
539 }
540 };
542 // Change status to sleeping
543 class JavaThreadSleepState : public JavaThreadStatusChanger {
544 private:
545 ThreadStatistics* _stat;
546 bool _active;
547 public:
548 JavaThreadSleepState(JavaThread *java_thread) :
549 JavaThreadStatusChanger(java_thread, java_lang_Thread::SLEEPING) {
550 if (is_alive()) {
551 _stat = java_thread->get_thread_stat();
552 _active = ThreadService::is_thread_monitoring_contention();
553 _stat->thread_sleep();
554 if (_active) {
555 _stat->thread_sleep_begin();
556 }
557 } else {
558 _active = false;
559 }
560 }
562 ~JavaThreadSleepState() {
563 if (_active) {
564 _stat->thread_sleep_end();
565 }
566 }
567 };