Wed, 27 Aug 2014 09:36:55 +0200
Merge
1 /*
2 * Copyright (c) 2003, 2013, 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 */
25 #ifndef SHARE_VM_SERVICES_THREADSERVICE_HPP
26 #define SHARE_VM_SERVICES_THREADSERVICE_HPP
28 #include "classfile/javaClasses.hpp"
29 #include "runtime/handles.hpp"
30 #include "runtime/init.hpp"
31 #include "runtime/jniHandles.hpp"
32 #include "runtime/objectMonitor.hpp"
33 #include "runtime/objectMonitor.inline.hpp"
34 #include "runtime/perfData.hpp"
35 #include "services/management.hpp"
36 #include "services/serviceUtil.hpp"
38 class OopClosure;
39 class ThreadDumpResult;
40 class ThreadStackTrace;
41 class ThreadSnapshot;
42 class StackFrameInfo;
43 class ThreadConcurrentLocks;
44 class DeadlockCycle;
46 // VM monitoring and management support for the thread and
47 // synchronization subsystem
48 //
49 // Thread contention monitoring is disabled by default.
50 // When enabled, the VM will begin measuring the accumulated
51 // elapsed time a thread blocked on synchronization.
52 //
53 class ThreadService : public AllStatic {
54 private:
55 // These counters could be moved to Threads class
56 static PerfCounter* _total_threads_count;
57 static PerfVariable* _live_threads_count;
58 static PerfVariable* _peak_threads_count;
59 static PerfVariable* _daemon_threads_count;
61 // These 2 counters are atomically incremented once the thread is exiting.
62 // They will be atomically decremented when ThreadService::remove_thread is called.
63 static volatile int _exiting_threads_count;
64 static volatile int _exiting_daemon_threads_count;
66 static bool _thread_monitoring_contention_enabled;
67 static bool _thread_cpu_time_enabled;
68 static bool _thread_allocated_memory_enabled;
70 // Need to keep the list of thread dump result that
71 // keep references to Method* since thread dump can be
72 // requested by multiple threads concurrently.
73 static ThreadDumpResult* _threaddump_list;
75 public:
76 static void init();
77 static void add_thread(JavaThread* thread, bool daemon);
78 static void remove_thread(JavaThread* thread, bool daemon);
79 static void current_thread_exiting(JavaThread* jt);
81 static bool set_thread_monitoring_contention(bool flag);
82 static bool is_thread_monitoring_contention() { return _thread_monitoring_contention_enabled; }
84 static bool set_thread_cpu_time_enabled(bool flag);
85 static bool is_thread_cpu_time_enabled() { return _thread_cpu_time_enabled; }
87 static bool set_thread_allocated_memory_enabled(bool flag);
88 static bool is_thread_allocated_memory_enabled() { return _thread_cpu_time_enabled; }
90 static jlong get_total_thread_count() { return _total_threads_count->get_value(); }
91 static jlong get_peak_thread_count() { return _peak_threads_count->get_value(); }
92 static jlong get_live_thread_count() { return _live_threads_count->get_value() - _exiting_threads_count; }
93 static jlong get_daemon_thread_count() { return _daemon_threads_count->get_value() - _exiting_daemon_threads_count; }
95 static int exiting_threads_count() { return _exiting_threads_count; }
96 static int exiting_daemon_threads_count() { return _exiting_daemon_threads_count; }
98 // Support for thread dump
99 static void add_thread_dump(ThreadDumpResult* dump);
100 static void remove_thread_dump(ThreadDumpResult* dump);
102 static Handle get_current_contended_monitor(JavaThread* thread);
104 // This function is called by JVM_DumpThreads.
105 static Handle dump_stack_traces(GrowableArray<instanceHandle>* threads,
106 int num_threads, TRAPS);
108 static void reset_peak_thread_count();
109 static void reset_contention_count_stat(JavaThread* thread);
110 static void reset_contention_time_stat(JavaThread* thread);
112 static DeadlockCycle* find_deadlocks_at_safepoint(bool object_monitors_only);
114 // GC support
115 static void oops_do(OopClosure* f);
116 static void metadata_do(void f(Metadata*));
117 };
119 // Per-thread Statistics for synchronization
120 class ThreadStatistics : public CHeapObj<mtInternal> {
121 private:
122 // The following contention statistics are only updated by
123 // the thread owning these statistics when contention occurs.
125 jlong _contended_enter_count;
126 elapsedTimer _contended_enter_timer;
127 jlong _monitor_wait_count;
128 elapsedTimer _monitor_wait_timer;
129 jlong _sleep_count;
130 elapsedTimer _sleep_timer;
133 // These two reset flags are set to true when another thread
134 // requests to reset the statistics. The actual statistics
135 // are reset when the thread contention occurs and attempts
136 // to update the statistics.
137 bool _count_pending_reset;
138 bool _timer_pending_reset;
140 // Keep accurate times for potentially recursive class operations
141 int _perf_recursion_counts[6];
142 elapsedTimer _perf_timers[6];
144 // utility functions
145 void check_and_reset_count() {
146 if (!_count_pending_reset) return;
147 _contended_enter_count = 0;
148 _monitor_wait_count = 0;
149 _sleep_count = 0;
150 _count_pending_reset = 0;
151 }
152 void check_and_reset_timer() {
153 if (!_timer_pending_reset) return;
154 _contended_enter_timer.reset();
155 _monitor_wait_timer.reset();
156 _sleep_timer.reset();
157 _timer_pending_reset = 0;
158 }
160 public:
161 ThreadStatistics();
163 jlong contended_enter_count() { return (_count_pending_reset ? 0 : _contended_enter_count); }
164 jlong contended_enter_ticks() { return (_timer_pending_reset ? 0 : _contended_enter_timer.active_ticks()); }
165 jlong monitor_wait_count() { return (_count_pending_reset ? 0 : _monitor_wait_count); }
166 jlong monitor_wait_ticks() { return (_timer_pending_reset ? 0 : _monitor_wait_timer.active_ticks()); }
167 jlong sleep_count() { return (_count_pending_reset ? 0 : _sleep_count); }
168 jlong sleep_ticks() { return (_timer_pending_reset ? 0 : _sleep_timer.active_ticks()); }
170 void monitor_wait() { check_and_reset_count(); _monitor_wait_count++; }
171 void monitor_wait_begin() { check_and_reset_timer(); _monitor_wait_timer.start(); }
172 void monitor_wait_end() { _monitor_wait_timer.stop(); check_and_reset_timer(); }
174 void thread_sleep() { check_and_reset_count(); _sleep_count++; }
175 void thread_sleep_begin() { check_and_reset_timer(); _sleep_timer.start(); }
176 void thread_sleep_end() { _sleep_timer.stop(); check_and_reset_timer(); }
178 void contended_enter() { check_and_reset_count(); _contended_enter_count++; }
179 void contended_enter_begin() { check_and_reset_timer(); _contended_enter_timer.start(); }
180 void contended_enter_end() { _contended_enter_timer.stop(); check_and_reset_timer(); }
182 void reset_count_stat() { _count_pending_reset = true; }
183 void reset_time_stat() { _timer_pending_reset = true; }
185 int* perf_recursion_counts_addr() { return _perf_recursion_counts; }
186 elapsedTimer* perf_timers_addr() { return _perf_timers; }
187 };
189 // Thread snapshot to represent the thread state and statistics
190 class ThreadSnapshot : public CHeapObj<mtInternal> {
191 private:
192 JavaThread* _thread;
193 oop _threadObj;
194 java_lang_Thread::ThreadStatus _thread_status;
196 bool _is_ext_suspended;
197 bool _is_in_native;
199 jlong _contended_enter_ticks;
200 jlong _contended_enter_count;
201 jlong _monitor_wait_ticks;
202 jlong _monitor_wait_count;
203 jlong _sleep_ticks;
204 jlong _sleep_count;
205 oop _blocker_object;
206 oop _blocker_object_owner;
208 ThreadStackTrace* _stack_trace;
209 ThreadConcurrentLocks* _concurrent_locks;
210 ThreadSnapshot* _next;
212 public:
213 // Dummy snapshot
214 ThreadSnapshot() : _thread(NULL), _threadObj(NULL), _stack_trace(NULL), _concurrent_locks(NULL), _next(NULL),
215 _blocker_object(NULL), _blocker_object_owner(NULL) {};
216 ThreadSnapshot(JavaThread* thread);
217 ~ThreadSnapshot();
219 java_lang_Thread::ThreadStatus thread_status() { return _thread_status; }
221 oop threadObj() const { return _threadObj; }
223 void set_next(ThreadSnapshot* n) { _next = n; }
225 bool is_ext_suspended() { return _is_ext_suspended; }
226 bool is_in_native() { return _is_in_native; }
228 jlong contended_enter_count() { return _contended_enter_count; }
229 jlong contended_enter_ticks() { return _contended_enter_ticks; }
230 jlong monitor_wait_count() { return _monitor_wait_count; }
231 jlong monitor_wait_ticks() { return _monitor_wait_ticks; }
232 jlong sleep_count() { return _sleep_count; }
233 jlong sleep_ticks() { return _sleep_ticks; }
236 oop blocker_object() { return _blocker_object; }
237 oop blocker_object_owner() { return _blocker_object_owner; }
239 ThreadSnapshot* next() const { return _next; }
240 ThreadStackTrace* get_stack_trace() { return _stack_trace; }
241 ThreadConcurrentLocks* get_concurrent_locks() { return _concurrent_locks; }
243 void dump_stack_at_safepoint(int max_depth, bool with_locked_monitors);
244 void set_concurrent_locks(ThreadConcurrentLocks* l) { _concurrent_locks = l; }
245 void oops_do(OopClosure* f);
246 void metadata_do(void f(Metadata*));
247 };
249 class ThreadStackTrace : public CHeapObj<mtInternal> {
250 private:
251 JavaThread* _thread;
252 int _depth; // number of stack frames added
253 bool _with_locked_monitors;
254 GrowableArray<StackFrameInfo*>* _frames;
255 GrowableArray<oop>* _jni_locked_monitors;
257 public:
259 ThreadStackTrace(JavaThread* thread, bool with_locked_monitors);
260 ~ThreadStackTrace();
262 JavaThread* thread() { return _thread; }
263 StackFrameInfo* stack_frame_at(int i) { return _frames->at(i); }
264 int get_stack_depth() { return _depth; }
266 void add_stack_frame(javaVFrame* jvf);
267 void dump_stack_at_safepoint(int max_depth);
268 Handle allocate_fill_stack_trace_element_array(TRAPS);
269 void oops_do(OopClosure* f);
270 void metadata_do(void f(Metadata*));
271 GrowableArray<oop>* jni_locked_monitors() { return _jni_locked_monitors; }
272 int num_jni_locked_monitors() { return (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0); }
274 bool is_owned_monitor_on_stack(oop object);
275 void add_jni_locked_monitor(oop object) { _jni_locked_monitors->append(object); }
276 };
278 // StackFrameInfo for keeping Method* and bci during
279 // stack walking for later construction of StackTraceElement[]
280 // Java instances
281 class StackFrameInfo : public CHeapObj<mtInternal> {
282 private:
283 Method* _method;
284 int _bci;
285 GrowableArray<oop>* _locked_monitors; // list of object monitors locked by this frame
286 // We need to save the mirrors in the backtrace to keep the class
287 // from being unloaded while we still have this stack trace.
288 oop _class_holder;
290 public:
292 StackFrameInfo(javaVFrame* jvf, bool with_locked_monitors);
293 ~StackFrameInfo() {
294 if (_locked_monitors != NULL) {
295 delete _locked_monitors;
296 }
297 };
298 Method* method() const { return _method; }
299 int bci() const { return _bci; }
300 void oops_do(OopClosure* f);
301 void metadata_do(void f(Metadata*));
303 int num_locked_monitors() { return (_locked_monitors != NULL ? _locked_monitors->length() : 0); }
304 GrowableArray<oop>* locked_monitors() { return _locked_monitors; }
306 void print_on(outputStream* st) const;
307 };
309 class ThreadConcurrentLocks : public CHeapObj<mtInternal> {
310 private:
311 GrowableArray<instanceOop>* _owned_locks;
312 ThreadConcurrentLocks* _next;
313 JavaThread* _thread;
314 public:
315 ThreadConcurrentLocks(JavaThread* thread);
316 ~ThreadConcurrentLocks();
318 void add_lock(instanceOop o);
319 void set_next(ThreadConcurrentLocks* n) { _next = n; }
320 ThreadConcurrentLocks* next() { return _next; }
321 JavaThread* java_thread() { return _thread; }
322 GrowableArray<instanceOop>* owned_locks() { return _owned_locks; }
323 void oops_do(OopClosure* f);
324 };
326 class ConcurrentLocksDump : public StackObj {
327 private:
328 ThreadConcurrentLocks* _map;
329 ThreadConcurrentLocks* _last; // Last ThreadConcurrentLocks in the map
330 bool _retain_map_on_free;
332 void build_map(GrowableArray<oop>* aos_objects);
333 void add_lock(JavaThread* thread, instanceOop o);
335 public:
336 ConcurrentLocksDump(bool retain_map_on_free) : _map(NULL), _last(NULL), _retain_map_on_free(retain_map_on_free) {};
337 ConcurrentLocksDump() : _map(NULL), _last(NULL), _retain_map_on_free(false) {};
338 ~ConcurrentLocksDump();
340 void dump_at_safepoint();
341 ThreadConcurrentLocks* thread_concurrent_locks(JavaThread* thread);
342 void print_locks_on(JavaThread* t, outputStream* st);
343 };
345 class ThreadDumpResult : public StackObj {
346 private:
347 int _num_threads;
348 int _num_snapshots;
349 ThreadSnapshot* _snapshots;
350 ThreadSnapshot* _last;
351 ThreadDumpResult* _next;
352 public:
353 ThreadDumpResult();
354 ThreadDumpResult(int num_threads);
355 ~ThreadDumpResult();
357 void add_thread_snapshot(ThreadSnapshot* ts);
358 void set_next(ThreadDumpResult* next) { _next = next; }
359 ThreadDumpResult* next() { return _next; }
360 int num_threads() { return _num_threads; }
361 int num_snapshots() { return _num_snapshots; }
362 ThreadSnapshot* snapshots() { return _snapshots; }
363 void oops_do(OopClosure* f);
364 void metadata_do(void f(Metadata*));
365 };
367 class DeadlockCycle : public CHeapObj<mtInternal> {
368 private:
369 bool _is_deadlock;
370 GrowableArray<JavaThread*>* _threads;
371 DeadlockCycle* _next;
372 public:
373 DeadlockCycle();
374 ~DeadlockCycle();
376 DeadlockCycle* next() { return _next; }
377 void set_next(DeadlockCycle* d) { _next = d; }
378 void add_thread(JavaThread* t) { _threads->append(t); }
379 void reset() { _is_deadlock = false; _threads->clear(); }
380 void set_deadlock(bool value) { _is_deadlock = value; }
381 bool is_deadlock() { return _is_deadlock; }
382 int num_threads() { return _threads->length(); }
383 GrowableArray<JavaThread*>* threads() { return _threads; }
384 void print_on(outputStream* st) const;
385 };
387 // Utility class to get list of java threads.
388 class ThreadsListEnumerator : public StackObj {
389 private:
390 GrowableArray<instanceHandle>* _threads_array;
391 public:
392 ThreadsListEnumerator(Thread* cur_thread,
393 bool include_jvmti_agent_threads = false,
394 bool include_jni_attaching_threads = true);
395 int num_threads() { return _threads_array->length(); }
396 instanceHandle get_threadObj(int index) { return _threads_array->at(index); }
397 };
400 // abstract utility class to set new thread states, and restore previous after the block exits
401 class JavaThreadStatusChanger : public StackObj {
402 private:
403 java_lang_Thread::ThreadStatus _old_state;
404 JavaThread* _java_thread;
405 bool _is_alive;
407 void save_old_state(JavaThread* java_thread) {
408 _java_thread = java_thread;
409 _is_alive = is_alive(java_thread);
410 if (is_alive()) {
411 _old_state = java_lang_Thread::get_thread_status(_java_thread->threadObj());
412 }
413 }
415 public:
416 static void set_thread_status(JavaThread* java_thread,
417 java_lang_Thread::ThreadStatus state) {
418 java_lang_Thread::set_thread_status(java_thread->threadObj(), state);
419 }
421 void set_thread_status(java_lang_Thread::ThreadStatus state) {
422 if (is_alive()) {
423 set_thread_status(_java_thread, state);
424 }
425 }
427 JavaThreadStatusChanger(JavaThread* java_thread,
428 java_lang_Thread::ThreadStatus state) {
429 save_old_state(java_thread);
430 set_thread_status(state);
431 }
433 JavaThreadStatusChanger(JavaThread* java_thread) {
434 save_old_state(java_thread);
435 }
437 ~JavaThreadStatusChanger() {
438 set_thread_status(_old_state);
439 }
441 static bool is_alive(JavaThread* java_thread) {
442 return java_thread != NULL && java_thread->threadObj() != NULL;
443 }
445 bool is_alive() {
446 return _is_alive;
447 }
448 };
450 // Change status to waiting on an object (timed or indefinite)
451 class JavaThreadInObjectWaitState : public JavaThreadStatusChanger {
452 private:
453 ThreadStatistics* _stat;
454 bool _active;
456 public:
457 JavaThreadInObjectWaitState(JavaThread *java_thread, bool timed) :
458 JavaThreadStatusChanger(java_thread,
459 timed ? java_lang_Thread::IN_OBJECT_WAIT_TIMED : java_lang_Thread::IN_OBJECT_WAIT) {
460 if (is_alive()) {
461 _stat = java_thread->get_thread_stat();
462 _active = ThreadService::is_thread_monitoring_contention();
463 _stat->monitor_wait();
464 if (_active) {
465 _stat->monitor_wait_begin();
466 }
467 } else {
468 _active = false;
469 }
470 }
472 ~JavaThreadInObjectWaitState() {
473 if (_active) {
474 _stat->monitor_wait_end();
475 }
476 }
477 };
479 // Change status to parked (timed or indefinite)
480 class JavaThreadParkedState : public JavaThreadStatusChanger {
481 private:
482 ThreadStatistics* _stat;
483 bool _active;
485 public:
486 JavaThreadParkedState(JavaThread *java_thread, bool timed) :
487 JavaThreadStatusChanger(java_thread,
488 timed ? java_lang_Thread::PARKED_TIMED : java_lang_Thread::PARKED) {
489 if (is_alive()) {
490 _stat = java_thread->get_thread_stat();
491 _active = ThreadService::is_thread_monitoring_contention();
492 _stat->monitor_wait();
493 if (_active) {
494 _stat->monitor_wait_begin();
495 }
496 } else {
497 _active = false;
498 }
499 }
501 ~JavaThreadParkedState() {
502 if (_active) {
503 _stat->monitor_wait_end();
504 }
505 }
506 };
508 // Change status to blocked on (re-)entering a synchronization block
509 class JavaThreadBlockedOnMonitorEnterState : public JavaThreadStatusChanger {
510 private:
511 ThreadStatistics* _stat;
512 bool _active;
514 static bool contended_enter_begin(JavaThread *java_thread) {
515 set_thread_status(java_thread, java_lang_Thread::BLOCKED_ON_MONITOR_ENTER);
516 ThreadStatistics* stat = java_thread->get_thread_stat();
517 stat->contended_enter();
518 bool active = ThreadService::is_thread_monitoring_contention();
519 if (active) {
520 stat->contended_enter_begin();
521 }
522 return active;
523 }
525 public:
526 // java_thread is waiting thread being blocked on monitor reenter.
527 // Current thread is the notifying thread which holds the monitor.
528 static bool wait_reenter_begin(JavaThread *java_thread, ObjectMonitor *obj_m) {
529 assert((java_thread != NULL), "Java thread should not be null here");
530 bool active = false;
531 if (is_alive(java_thread) && ServiceUtil::visible_oop((oop)obj_m->object())) {
532 active = contended_enter_begin(java_thread);
533 }
534 return active;
535 }
537 static void wait_reenter_end(JavaThread *java_thread, bool active) {
538 if (active) {
539 java_thread->get_thread_stat()->contended_enter_end();
540 }
541 set_thread_status(java_thread, java_lang_Thread::RUNNABLE);
542 }
544 JavaThreadBlockedOnMonitorEnterState(JavaThread *java_thread, ObjectMonitor *obj_m) :
545 JavaThreadStatusChanger(java_thread) {
546 assert((java_thread != NULL), "Java thread should not be null here");
547 // Change thread status and collect contended enter stats for monitor contended
548 // enter done for external java world objects and it is contended. All other cases
549 // like for vm internal objects and for external objects which are not contended
550 // thread status is not changed and contended enter stat is not collected.
551 _active = false;
552 if (is_alive() && ServiceUtil::visible_oop((oop)obj_m->object()) && obj_m->contentions() > 0) {
553 _stat = java_thread->get_thread_stat();
554 _active = contended_enter_begin(java_thread);
555 }
556 }
558 ~JavaThreadBlockedOnMonitorEnterState() {
559 if (_active) {
560 _stat->contended_enter_end();
561 }
562 }
563 };
565 // Change status to sleeping
566 class JavaThreadSleepState : public JavaThreadStatusChanger {
567 private:
568 ThreadStatistics* _stat;
569 bool _active;
570 public:
571 JavaThreadSleepState(JavaThread *java_thread) :
572 JavaThreadStatusChanger(java_thread, java_lang_Thread::SLEEPING) {
573 if (is_alive()) {
574 _stat = java_thread->get_thread_stat();
575 _active = ThreadService::is_thread_monitoring_contention();
576 _stat->thread_sleep();
577 if (_active) {
578 _stat->thread_sleep_begin();
579 }
580 } else {
581 _active = false;
582 }
583 }
585 ~JavaThreadSleepState() {
586 if (_active) {
587 _stat->thread_sleep_end();
588 }
589 }
590 };
592 #endif // SHARE_VM_SERVICES_THREADSERVICE_HPP