1 /*
2 * Copyright 1997-2009 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 */
24
25 # include "incls/_precompiled.incl"
26 # include "incls/_thread.cpp.incl"
27
28 #ifdef DTRACE_ENABLED
29
30 // Only bother with this argument setup if dtrace is available
31
32 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
33 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
34 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
35 intptr_t, intptr_t, bool);
36 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
37 intptr_t, intptr_t, bool);
38
39 #define DTRACE_THREAD_PROBE(probe, javathread) \
40 { \
41 ResourceMark rm(this); \
42 int len = 0; \
43 const char* name = (javathread)->get_thread_name(); \
44 len = strlen(name); \
45 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
46 name, len, \
47 java_lang_Thread::thread_id((javathread)->threadObj()), \
48 (javathread)->osthread()->thread_id(), \
49 java_lang_Thread::is_daemon((javathread)->threadObj())); \
50 }
51
52 #else // ndef DTRACE_ENABLED
53
54 #define DTRACE_THREAD_PROBE(probe, javathread)
55
56 #endif // ndef DTRACE_ENABLED
57
58 // Class hierarchy
59 // - Thread
60 // - VMThread
61 // - WatcherThread
62 // - ConcurrentMarkSweepThread
63 // - JavaThread
64 // - CompilerThread
65
66 // ======= Thread ========
67
68 // Support for forcing alignment of thread objects for biased locking
69 void* Thread::operator new(size_t size) {
70 if (UseBiasedLocking) {
71 const int alignment = markOopDesc::biased_lock_alignment;
72 size_t aligned_size = size + (alignment - sizeof(intptr_t));
73 void* real_malloc_addr = CHeapObj::operator new(aligned_size);
74 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
75 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
76 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
77 "JavaThread alignment code overflowed allocated storage");
78 if (TraceBiasedLocking) {
79 if (aligned_addr != real_malloc_addr)
80 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
81 real_malloc_addr, aligned_addr);
82 }
83 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
84 return aligned_addr;
85 } else {
86 return CHeapObj::operator new(size);
87 }
88 }
89
90 void Thread::operator delete(void* p) {
91 if (UseBiasedLocking) {
92 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
93 CHeapObj::operator delete(real_malloc_addr);
94 } else {
95 CHeapObj::operator delete(p);
96 }
97 }
98
99
100 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
101 // JavaThread
102
103
104 Thread::Thread() {
105 // stack
106 _stack_base = NULL;
107 _stack_size = 0;
108 _self_raw_id = 0;
109 _lgrp_id = -1;
110 _osthread = NULL;
111
112 // allocated data structures
113 set_resource_area(new ResourceArea());
114 set_handle_area(new HandleArea(NULL));
115 set_active_handles(NULL);
116 set_free_handle_block(NULL);
117 set_last_handle_mark(NULL);
118 set_osthread(NULL);
119
120 // This initial value ==> never claimed.
121 _oops_do_parity = 0;
122
123 // the handle mark links itself to last_handle_mark
124 new HandleMark(this);
125
126 // plain initialization
127 debug_only(_owned_locks = NULL;)
128 debug_only(_allow_allocation_count = 0;)
129 NOT_PRODUCT(_allow_safepoint_count = 0;)
130 NOT_PRODUCT(_skip_gcalot = false;)
131 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
132 _jvmti_env_iteration_count = 0;
133 _vm_operation_started_count = 0;
134 _vm_operation_completed_count = 0;
135 _current_pending_monitor = NULL;
136 _current_pending_monitor_is_from_java = true;
137 _current_waiting_monitor = NULL;
138 _num_nested_signal = 0;
139 omFreeList = NULL ;
140 omFreeCount = 0 ;
141 omFreeProvision = 32 ;
142
143 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
144 _suspend_flags = 0;
145
146 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
147 _hashStateX = os::random() ;
148 _hashStateY = 842502087 ;
149 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
150 _hashStateW = 273326509 ;
151
152 _OnTrap = 0 ;
153 _schedctl = NULL ;
154 _Stalled = 0 ;
155 _TypeTag = 0x2BAD ;
156
157 // Many of the following fields are effectively final - immutable
158 // Note that nascent threads can't use the Native Monitor-Mutex
159 // construct until the _MutexEvent is initialized ...
160 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
161 // we might instead use a stack of ParkEvents that we could provision on-demand.
162 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
163 // and ::Release()
164 _ParkEvent = ParkEvent::Allocate (this) ;
165 _SleepEvent = ParkEvent::Allocate (this) ;
166 _MutexEvent = ParkEvent::Allocate (this) ;
167 _MuxEvent = ParkEvent::Allocate (this) ;
168
169 #ifdef CHECK_UNHANDLED_OOPS
170 if (CheckUnhandledOops) {
171 _unhandled_oops = new UnhandledOops(this);
172 }
173 #endif // CHECK_UNHANDLED_OOPS
174 #ifdef ASSERT
175 if (UseBiasedLocking) {
176 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
177 assert(this == _real_malloc_address ||
178 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
179 "bug in forced alignment of thread objects");
180 }
181 #endif /* ASSERT */
182 }
183
184 void Thread::initialize_thread_local_storage() {
185 // Note: Make sure this method only calls
186 // non-blocking operations. Otherwise, it might not work
187 // with the thread-startup/safepoint interaction.
188
189 // During Java thread startup, safepoint code should allow this
190 // method to complete because it may need to allocate memory to
191 // store information for the new thread.
192
193 // initialize structure dependent on thread local storage
194 ThreadLocalStorage::set_thread(this);
195
196 // set up any platform-specific state.
197 os::initialize_thread();
198
199 }
200
201 void Thread::record_stack_base_and_size() {
202 set_stack_base(os::current_stack_base());
203 set_stack_size(os::current_stack_size());
204 }
205
206
207 Thread::~Thread() {
208 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
209 ObjectSynchronizer::omFlush (this) ;
210
211 // deallocate data structures
212 delete resource_area();
213 // since the handle marks are using the handle area, we have to deallocated the root
214 // handle mark before deallocating the thread's handle area,
215 assert(last_handle_mark() != NULL, "check we have an element");
216 delete last_handle_mark();
217 assert(last_handle_mark() == NULL, "check we have reached the end");
218
219 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
220 // We NULL out the fields for good hygiene.
221 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
222 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
223 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
224 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
225
226 delete handle_area();
227
228 // osthread() can be NULL, if creation of thread failed.
229 if (osthread() != NULL) os::free_thread(osthread());
230
231 delete _SR_lock;
232
233 // clear thread local storage if the Thread is deleting itself
234 if (this == Thread::current()) {
235 ThreadLocalStorage::set_thread(NULL);
236 } else {
237 // In the case where we're not the current thread, invalidate all the
238 // caches in case some code tries to get the current thread or the
239 // thread that was destroyed, and gets stale information.
240 ThreadLocalStorage::invalidate_all();
241 }
242 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
243 }
244
245 // NOTE: dummy function for assertion purpose.
246 void Thread::run() {
247 ShouldNotReachHere();
248 }
249
250 #ifdef ASSERT
251 // Private method to check for dangling thread pointer
252 void check_for_dangling_thread_pointer(Thread *thread) {
253 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
254 "possibility of dangling Thread pointer");
255 }
256 #endif
257
258
259 #ifndef PRODUCT
260 // Tracing method for basic thread operations
261 void Thread::trace(const char* msg, const Thread* const thread) {
262 if (!TraceThreadEvents) return;
263 ResourceMark rm;
264 ThreadCritical tc;
265 const char *name = "non-Java thread";
266 int prio = -1;
267 if (thread->is_Java_thread()
268 && !thread->is_Compiler_thread()) {
269 // The Threads_lock must be held to get information about
270 // this thread but may not be in some situations when
271 // tracing thread events.
272 bool release_Threads_lock = false;
273 if (!Threads_lock->owned_by_self()) {
274 Threads_lock->lock();
275 release_Threads_lock = true;
276 }
277 JavaThread* jt = (JavaThread *)thread;
278 name = (char *)jt->get_thread_name();
279 oop thread_oop = jt->threadObj();
280 if (thread_oop != NULL) {
281 prio = java_lang_Thread::priority(thread_oop);
282 }
283 if (release_Threads_lock) {
284 Threads_lock->unlock();
285 }
286 }
287 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
288 }
289 #endif
290
291
292 ThreadPriority Thread::get_priority(const Thread* const thread) {
293 trace("get priority", thread);
294 ThreadPriority priority;
295 // Can return an error!
296 (void)os::get_priority(thread, priority);
297 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
298 return priority;
299 }
300
301 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
302 trace("set priority", thread);
303 debug_only(check_for_dangling_thread_pointer(thread);)
304 // Can return an error!
305 (void)os::set_priority(thread, priority);
306 }
307
308
309 void Thread::start(Thread* thread) {
310 trace("start", thread);
311 // Start is different from resume in that its safety is guaranteed by context or
312 // being called from a Java method synchronized on the Thread object.
313 if (!DisableStartThread) {
314 if (thread->is_Java_thread()) {
315 // Initialize the thread state to RUNNABLE before starting this thread.
316 // Can not set it after the thread started because we do not know the
317 // exact thread state at that time. It could be in MONITOR_WAIT or
318 // in SLEEPING or some other state.
319 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
320 java_lang_Thread::RUNNABLE);
321 }
322 os::start_thread(thread);
323 }
324 }
325
326 // Enqueue a VM_Operation to do the job for us - sometime later
327 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
328 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
329 VMThread::execute(vm_stop);
330 }
331
332
333 //
334 // Check if an external suspend request has completed (or has been
335 // cancelled). Returns true if the thread is externally suspended and
336 // false otherwise.
337 //
338 // The bits parameter returns information about the code path through
339 // the routine. Useful for debugging:
340 //
341 // set in is_ext_suspend_completed():
342 // 0x00000001 - routine was entered
343 // 0x00000010 - routine return false at end
344 // 0x00000100 - thread exited (return false)
345 // 0x00000200 - suspend request cancelled (return false)
346 // 0x00000400 - thread suspended (return true)
347 // 0x00001000 - thread is in a suspend equivalent state (return true)
348 // 0x00002000 - thread is native and walkable (return true)
349 // 0x00004000 - thread is native_trans and walkable (needed retry)
350 //
351 // set in wait_for_ext_suspend_completion():
352 // 0x00010000 - routine was entered
353 // 0x00020000 - suspend request cancelled before loop (return false)
354 // 0x00040000 - thread suspended before loop (return true)
355 // 0x00080000 - suspend request cancelled in loop (return false)
356 // 0x00100000 - thread suspended in loop (return true)
357 // 0x00200000 - suspend not completed during retry loop (return false)
358 //
359
360 // Helper class for tracing suspend wait debug bits.
361 //
362 // 0x00000100 indicates that the target thread exited before it could
363 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
364 // 0x00080000 each indicate a cancelled suspend request so they don't
365 // count as wait failures either.
366 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
367
368 class TraceSuspendDebugBits : public StackObj {
369 private:
370 JavaThread * jt;
371 bool is_wait;
372 bool called_by_wait; // meaningful when !is_wait
373 uint32_t * bits;
374
375 public:
376 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
377 uint32_t *_bits) {
378 jt = _jt;
379 is_wait = _is_wait;
380 called_by_wait = _called_by_wait;
381 bits = _bits;
382 }
383
384 ~TraceSuspendDebugBits() {
385 if (!is_wait) {
386 #if 1
387 // By default, don't trace bits for is_ext_suspend_completed() calls.
388 // That trace is very chatty.
389 return;
390 #else
391 if (!called_by_wait) {
392 // If tracing for is_ext_suspend_completed() is enabled, then only
393 // trace calls to it from wait_for_ext_suspend_completion()
394 return;
395 }
396 #endif
397 }
398
399 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
400 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
401 MutexLocker ml(Threads_lock); // needed for get_thread_name()
402 ResourceMark rm;
403
404 tty->print_cr(
405 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
406 jt->get_thread_name(), *bits);
407
408 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
409 }
410 }
411 }
412 };
413 #undef DEBUG_FALSE_BITS
414
415
416 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
417 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
418
419 bool did_trans_retry = false; // only do thread_in_native_trans retry once
420 bool do_trans_retry; // flag to force the retry
421
422 *bits |= 0x00000001;
423
424 do {
425 do_trans_retry = false;
426
427 if (is_exiting()) {
428 // Thread is in the process of exiting. This is always checked
429 // first to reduce the risk of dereferencing a freed JavaThread.
430 *bits |= 0x00000100;
431 return false;
432 }
433
434 if (!is_external_suspend()) {
435 // Suspend request is cancelled. This is always checked before
436 // is_ext_suspended() to reduce the risk of a rogue resume
437 // confusing the thread that made the suspend request.
438 *bits |= 0x00000200;
439 return false;
440 }
441
442 if (is_ext_suspended()) {
443 // thread is suspended
444 *bits |= 0x00000400;
445 return true;
446 }
447
448 // Now that we no longer do hard suspends of threads running
449 // native code, the target thread can be changing thread state
450 // while we are in this routine:
451 //
452 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
453 //
454 // We save a copy of the thread state as observed at this moment
455 // and make our decision about suspend completeness based on the
456 // copy. This closes the race where the thread state is seen as
457 // _thread_in_native_trans in the if-thread_blocked check, but is
458 // seen as _thread_blocked in if-thread_in_native_trans check.
459 JavaThreadState save_state = thread_state();
460
461 if (save_state == _thread_blocked && is_suspend_equivalent()) {
462 // If the thread's state is _thread_blocked and this blocking
463 // condition is known to be equivalent to a suspend, then we can
464 // consider the thread to be externally suspended. This means that
465 // the code that sets _thread_blocked has been modified to do
466 // self-suspension if the blocking condition releases. We also
467 // used to check for CONDVAR_WAIT here, but that is now covered by
468 // the _thread_blocked with self-suspension check.
469 //
470 // Return true since we wouldn't be here unless there was still an
471 // external suspend request.
472 *bits |= 0x00001000;
473 return true;
474 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
475 // Threads running native code will self-suspend on native==>VM/Java
476 // transitions. If its stack is walkable (should always be the case
477 // unless this function is called before the actual java_suspend()
478 // call), then the wait is done.
479 *bits |= 0x00002000;
480 return true;
481 } else if (!called_by_wait && !did_trans_retry &&
482 save_state == _thread_in_native_trans &&
483 frame_anchor()->walkable()) {
484 // The thread is transitioning from thread_in_native to another
485 // thread state. check_safepoint_and_suspend_for_native_trans()
486 // will force the thread to self-suspend. If it hasn't gotten
487 // there yet we may have caught the thread in-between the native
488 // code check above and the self-suspend. Lucky us. If we were
489 // called by wait_for_ext_suspend_completion(), then it
490 // will be doing the retries so we don't have to.
491 //
492 // Since we use the saved thread state in the if-statement above,
493 // there is a chance that the thread has already transitioned to
494 // _thread_blocked by the time we get here. In that case, we will
495 // make a single unnecessary pass through the logic below. This
496 // doesn't hurt anything since we still do the trans retry.
497
498 *bits |= 0x00004000;
499
500 // Once the thread leaves thread_in_native_trans for another
501 // thread state, we break out of this retry loop. We shouldn't
502 // need this flag to prevent us from getting back here, but
503 // sometimes paranoia is good.
504 did_trans_retry = true;
505
506 // We wait for the thread to transition to a more usable state.
507 for (int i = 1; i <= SuspendRetryCount; i++) {
508 // We used to do an "os::yield_all(i)" call here with the intention
509 // that yielding would increase on each retry. However, the parameter
510 // is ignored on Linux which means the yield didn't scale up. Waiting
511 // on the SR_lock below provides a much more predictable scale up for
512 // the delay. It also provides a simple/direct point to check for any
513 // safepoint requests from the VMThread
514
515 // temporarily drops SR_lock while doing wait with safepoint check
516 // (if we're a JavaThread - the WatcherThread can also call this)
517 // and increase delay with each retry
518 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
519
520 // check the actual thread state instead of what we saved above
521 if (thread_state() != _thread_in_native_trans) {
522 // the thread has transitioned to another thread state so
523 // try all the checks (except this one) one more time.
524 do_trans_retry = true;
525 break;
526 }
527 } // end retry loop
528
529
530 }
531 } while (do_trans_retry);
532
533 *bits |= 0x00000010;
534 return false;
535 }
536
537 //
538 // Wait for an external suspend request to complete (or be cancelled).
539 // Returns true if the thread is externally suspended and false otherwise.
540 //
541 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
542 uint32_t *bits) {
543 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
544 false /* !called_by_wait */, bits);
545
546 // local flag copies to minimize SR_lock hold time
547 bool is_suspended;
548 bool pending;
549 uint32_t reset_bits;
550
551 // set a marker so is_ext_suspend_completed() knows we are the caller
552 *bits |= 0x00010000;
553
554 // We use reset_bits to reinitialize the bits value at the top of
555 // each retry loop. This allows the caller to make use of any
556 // unused bits for their own marking purposes.
557 reset_bits = *bits;
558
559 {
560 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
561 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
562 delay, bits);
563 pending = is_external_suspend();
564 }
565 // must release SR_lock to allow suspension to complete
566
567 if (!pending) {
568 // A cancelled suspend request is the only false return from
569 // is_ext_suspend_completed() that keeps us from entering the
570 // retry loop.
571 *bits |= 0x00020000;
572 return false;
573 }
574
575 if (is_suspended) {
576 *bits |= 0x00040000;
577 return true;
578 }
579
580 for (int i = 1; i <= retries; i++) {
581 *bits = reset_bits; // reinit to only track last retry
582
583 // We used to do an "os::yield_all(i)" call here with the intention
584 // that yielding would increase on each retry. However, the parameter
585 // is ignored on Linux which means the yield didn't scale up. Waiting
586 // on the SR_lock below provides a much more predictable scale up for
587 // the delay. It also provides a simple/direct point to check for any
588 // safepoint requests from the VMThread
589
590 {
591 MutexLocker ml(SR_lock());
592 // wait with safepoint check (if we're a JavaThread - the WatcherThread
593 // can also call this) and increase delay with each retry
594 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
595
596 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
597 delay, bits);
598
599 // It is possible for the external suspend request to be cancelled
600 // (by a resume) before the actual suspend operation is completed.
601 // Refresh our local copy to see if we still need to wait.
602 pending = is_external_suspend();
603 }
604
605 if (!pending) {
606 // A cancelled suspend request is the only false return from
607 // is_ext_suspend_completed() that keeps us from staying in the
608 // retry loop.
609 *bits |= 0x00080000;
610 return false;
611 }
612
613 if (is_suspended) {
614 *bits |= 0x00100000;
615 return true;
616 }
617 } // end retry loop
618
619 // thread did not suspend after all our retries
620 *bits |= 0x00200000;
621 return false;
622 }
623
624 #ifndef PRODUCT
625 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
626
627 // This should not need to be atomic as the only way for simultaneous
628 // updates is via interrupts. Even then this should be rare or non-existant
629 // and we don't care that much anyway.
630
631 int index = _jmp_ring_index;
632 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
633 _jmp_ring[index]._target = (intptr_t) target;
634 _jmp_ring[index]._instruction = (intptr_t) instr;
635 _jmp_ring[index]._file = file;
636 _jmp_ring[index]._line = line;
637 }
638 #endif /* PRODUCT */
639
640 // Called by flat profiler
641 // Callers have already called wait_for_ext_suspend_completion
642 // The assertion for that is currently too complex to put here:
643 bool JavaThread::profile_last_Java_frame(frame* _fr) {
644 bool gotframe = false;
645 // self suspension saves needed state.
646 if (has_last_Java_frame() && _anchor.walkable()) {
647 *_fr = pd_last_frame();
648 gotframe = true;
649 }
650 return gotframe;
651 }
652
653 void Thread::interrupt(Thread* thread) {
654 trace("interrupt", thread);
655 debug_only(check_for_dangling_thread_pointer(thread);)
656 os::interrupt(thread);
657 }
658
659 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
660 trace("is_interrupted", thread);
661 debug_only(check_for_dangling_thread_pointer(thread);)
662 // Note: If clear_interrupted==false, this simply fetches and
663 // returns the value of the field osthread()->interrupted().
664 return os::is_interrupted(thread, clear_interrupted);
665 }
666
667
668 // GC Support
669 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
670 jint thread_parity = _oops_do_parity;
671 if (thread_parity != strong_roots_parity) {
672 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
673 if (res == thread_parity) return true;
674 else {
675 guarantee(res == strong_roots_parity, "Or else what?");
676 assert(SharedHeap::heap()->n_par_threads() > 0,
677 "Should only fail when parallel.");
678 return false;
679 }
680 }
681 assert(SharedHeap::heap()->n_par_threads() > 0,
682 "Should only fail when parallel.");
683 return false;
684 }
685
686 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
687 active_handles()->oops_do(f);
688 // Do oop for ThreadShadow
689 f->do_oop((oop*)&_pending_exception);
690 handle_area()->oops_do(f);
691 }
692
693 void Thread::nmethods_do(CodeBlobClosure* cf) {
694 // no nmethods in a generic thread...
695 }
696
697 void Thread::print_on(outputStream* st) const {
698 // get_priority assumes osthread initialized
699 if (osthread() != NULL) {
700 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
701 osthread()->print_on(st);
702 }
703 debug_only(if (WizardMode) print_owned_locks_on(st);)
704 }
705
706 // Thread::print_on_error() is called by fatal error handler. Don't use
707 // any lock or allocate memory.
708 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
709 if (is_VM_thread()) st->print("VMThread");
710 else if (is_Compiler_thread()) st->print("CompilerThread");
711 else if (is_Java_thread()) st->print("JavaThread");
712 else if (is_GC_task_thread()) st->print("GCTaskThread");
713 else if (is_Watcher_thread()) st->print("WatcherThread");
714 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
715 else st->print("Thread");
716
717 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
718 _stack_base - _stack_size, _stack_base);
719
720 if (osthread()) {
721 st->print(" [id=%d]", osthread()->thread_id());
722 }
723 }
724
725 #ifdef ASSERT
726 void Thread::print_owned_locks_on(outputStream* st) const {
727 Monitor *cur = _owned_locks;
728 if (cur == NULL) {
729 st->print(" (no locks) ");
730 } else {
731 st->print_cr(" Locks owned:");
732 while(cur) {
733 cur->print_on(st);
734 cur = cur->next();
735 }
736 }
737 }
738
739 static int ref_use_count = 0;
740
741 bool Thread::owns_locks_but_compiled_lock() const {
742 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
743 if (cur != Compile_lock) return true;
744 }
745 return false;
746 }
747
748
749 #endif
750
751 #ifndef PRODUCT
752
753 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
754 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
755 // no threads which allow_vm_block's are held
756 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
757 // Check if current thread is allowed to block at a safepoint
758 if (!(_allow_safepoint_count == 0))
759 fatal("Possible safepoint reached by thread that does not allow it");
760 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
761 fatal("LEAF method calling lock?");
762 }
763
764 #ifdef ASSERT
765 if (potential_vm_operation && is_Java_thread()
766 && !Universe::is_bootstrapping()) {
767 // Make sure we do not hold any locks that the VM thread also uses.
768 // This could potentially lead to deadlocks
769 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
770 // Threads_lock is special, since the safepoint synchronization will not start before this is
771 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
772 // since it is used to transfer control between JavaThreads and the VMThread
773 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
774 if ( (cur->allow_vm_block() &&
775 cur != Threads_lock &&
776 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
777 cur != VMOperationRequest_lock &&
778 cur != VMOperationQueue_lock) ||
779 cur->rank() == Mutex::special) {
780 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
781 }
782 }
783 }
784
785 if (GCALotAtAllSafepoints) {
786 // We could enter a safepoint here and thus have a gc
787 InterfaceSupport::check_gc_alot();
788 }
789 #endif
790 }
791 #endif
792
793 bool Thread::is_in_stack(address adr) const {
794 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
795 address end = os::current_stack_pointer();
796 if (stack_base() >= adr && adr >= end) return true;
797
798 return false;
799 }
800
801
802 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
803 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
804 // used for compilation in the future. If that change is made, the need for these methods
805 // should be revisited, and they should be removed if possible.
806
807 bool Thread::is_lock_owned(address adr) const {
808 return (_stack_base >= adr && adr >= (_stack_base - _stack_size));
809 }
810
811 bool Thread::set_as_starting_thread() {
812 // NOTE: this must be called inside the main thread.
813 return os::create_main_thread((JavaThread*)this);
814 }
815
816 static void initialize_class(symbolHandle class_name, TRAPS) {
817 klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
818 instanceKlass::cast(klass)->initialize(CHECK);
819 }
820
821
822 // Creates the initial ThreadGroup
823 static Handle create_initial_thread_group(TRAPS) {
824 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_ThreadGroup(), true, CHECK_NH);
825 instanceKlassHandle klass (THREAD, k);
826
827 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
828 {
829 JavaValue result(T_VOID);
830 JavaCalls::call_special(&result,
831 system_instance,
832 klass,
833 vmSymbolHandles::object_initializer_name(),
834 vmSymbolHandles::void_method_signature(),
835 CHECK_NH);
836 }
837 Universe::set_system_thread_group(system_instance());
838
839 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
840 {
841 JavaValue result(T_VOID);
842 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
843 JavaCalls::call_special(&result,
844 main_instance,
845 klass,
846 vmSymbolHandles::object_initializer_name(),
847 vmSymbolHandles::threadgroup_string_void_signature(),
848 system_instance,
849 string,
850 CHECK_NH);
851 }
852 return main_instance;
853 }
854
855 // Creates the initial Thread
856 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
857 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK_NULL);
858 instanceKlassHandle klass (THREAD, k);
859 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
860
861 java_lang_Thread::set_thread(thread_oop(), thread);
862 java_lang_Thread::set_priority(thread_oop(), NormPriority);
863 thread->set_threadObj(thread_oop());
864
865 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
866
867 JavaValue result(T_VOID);
868 JavaCalls::call_special(&result, thread_oop,
869 klass,
870 vmSymbolHandles::object_initializer_name(),
871 vmSymbolHandles::threadgroup_string_void_signature(),
872 thread_group,
873 string,
874 CHECK_NULL);
875 return thread_oop();
876 }
877
878 static void call_initializeSystemClass(TRAPS) {
879 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
880 instanceKlassHandle klass (THREAD, k);
881
882 JavaValue result(T_VOID);
883 JavaCalls::call_static(&result, klass, vmSymbolHandles::initializeSystemClass_name(),
884 vmSymbolHandles::void_method_signature(), CHECK);
885 }
886
887 static void reset_vm_info_property(TRAPS) {
888 // the vm info string
889 ResourceMark rm(THREAD);
890 const char *vm_info = VM_Version::vm_info_string();
891
892 // java.lang.System class
893 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
894 instanceKlassHandle klass (THREAD, k);
895
896 // setProperty arguments
897 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
898 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
899
900 // return value
901 JavaValue r(T_OBJECT);
902
903 // public static String setProperty(String key, String value);
904 JavaCalls::call_static(&r,
905 klass,
906 vmSymbolHandles::setProperty_name(),
907 vmSymbolHandles::string_string_string_signature(),
908 key_str,
909 value_str,
910 CHECK);
911 }
912
913
914 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
915 assert(thread_group.not_null(), "thread group should be specified");
916 assert(threadObj() == NULL, "should only create Java thread object once");
917
918 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
919 instanceKlassHandle klass (THREAD, k);
920 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
921
922 java_lang_Thread::set_thread(thread_oop(), this);
923 java_lang_Thread::set_priority(thread_oop(), NormPriority);
924 set_threadObj(thread_oop());
925
926 JavaValue result(T_VOID);
927 if (thread_name != NULL) {
928 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
929 // Thread gets assigned specified name and null target
930 JavaCalls::call_special(&result,
931 thread_oop,
932 klass,
933 vmSymbolHandles::object_initializer_name(),
934 vmSymbolHandles::threadgroup_string_void_signature(),
935 thread_group, // Argument 1
936 name, // Argument 2
937 THREAD);
938 } else {
939 // Thread gets assigned name "Thread-nnn" and null target
940 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
941 JavaCalls::call_special(&result,
942 thread_oop,
943 klass,
944 vmSymbolHandles::object_initializer_name(),
945 vmSymbolHandles::threadgroup_runnable_void_signature(),
946 thread_group, // Argument 1
947 Handle(), // Argument 2
948 THREAD);
949 }
950
951
952 if (daemon) {
953 java_lang_Thread::set_daemon(thread_oop());
954 }
955
956 if (HAS_PENDING_EXCEPTION) {
957 return;
958 }
959
960 KlassHandle group(this, SystemDictionary::threadGroup_klass());
961 Handle threadObj(this, this->threadObj());
962
963 JavaCalls::call_special(&result,
964 thread_group,
965 group,
966 vmSymbolHandles::add_method_name(),
967 vmSymbolHandles::thread_void_signature(),
968 threadObj, // Arg 1
969 THREAD);
970
971
972 }
973
974 // NamedThread -- non-JavaThread subclasses with multiple
975 // uniquely named instances should derive from this.
976 NamedThread::NamedThread() : Thread() {
977 _name = NULL;
978 }
979
980 NamedThread::~NamedThread() {
981 if (_name != NULL) {
982 FREE_C_HEAP_ARRAY(char, _name);
983 _name = NULL;
984 }
985 }
986
987 void NamedThread::set_name(const char* format, ...) {
988 guarantee(_name == NULL, "Only get to set name once.");
989 _name = NEW_C_HEAP_ARRAY(char, max_name_len);
990 guarantee(_name != NULL, "alloc failure");
991 va_list ap;
992 va_start(ap, format);
993 jio_vsnprintf(_name, max_name_len, format, ap);
994 va_end(ap);
995 }
996
997 // ======= WatcherThread ========
998
999 // The watcher thread exists to simulate timer interrupts. It should
1000 // be replaced by an abstraction over whatever native support for
1001 // timer interrupts exists on the platform.
1002
1003 WatcherThread* WatcherThread::_watcher_thread = NULL;
1004 bool WatcherThread::_should_terminate = false;
1005
1006 WatcherThread::WatcherThread() : Thread() {
1007 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1008 if (os::create_thread(this, os::watcher_thread)) {
1009 _watcher_thread = this;
1010
1011 // Set the watcher thread to the highest OS priority which should not be
1012 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1013 // is created. The only normal thread using this priority is the reference
1014 // handler thread, which runs for very short intervals only.
1015 // If the VMThread's priority is not lower than the WatcherThread profiling
1016 // will be inaccurate.
1017 os::set_priority(this, MaxPriority);
1018 if (!DisableStartThread) {
1019 os::start_thread(this);
1020 }
1021 }
1022 }
1023
1024 void WatcherThread::run() {
1025 assert(this == watcher_thread(), "just checking");
1026
1027 this->record_stack_base_and_size();
1028 this->initialize_thread_local_storage();
1029 this->set_active_handles(JNIHandleBlock::allocate_block());
1030 while(!_should_terminate) {
1031 assert(watcher_thread() == Thread::current(), "thread consistency check");
1032 assert(watcher_thread() == this, "thread consistency check");
1033
1034 // Calculate how long it'll be until the next PeriodicTask work
1035 // should be done, and sleep that amount of time.
1036 const size_t time_to_wait = PeriodicTask::time_to_wait();
1037 os::sleep(this, time_to_wait, false);
1038
1039 if (is_error_reported()) {
1040 // A fatal error has happened, the error handler(VMError::report_and_die)
1041 // should abort JVM after creating an error log file. However in some
1042 // rare cases, the error handler itself might deadlock. Here we try to
1043 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1044 //
1045 // This code is in WatcherThread because WatcherThread wakes up
1046 // periodically so the fatal error handler doesn't need to do anything;
1047 // also because the WatcherThread is less likely to crash than other
1048 // threads.
1049
1050 for (;;) {
1051 if (!ShowMessageBoxOnError
1052 && (OnError == NULL || OnError[0] == '\0')
1053 && Arguments::abort_hook() == NULL) {
1054 os::sleep(this, 2 * 60 * 1000, false);
1055 fdStream err(defaultStream::output_fd());
1056 err.print_raw_cr("# [ timer expired, abort... ]");
1057 // skip atexit/vm_exit/vm_abort hooks
1058 os::die();
1059 }
1060
1061 // Wake up 5 seconds later, the fatal handler may reset OnError or
1062 // ShowMessageBoxOnError when it is ready to abort.
1063 os::sleep(this, 5 * 1000, false);
1064 }
1065 }
1066
1067 PeriodicTask::real_time_tick(time_to_wait);
1068
1069 // If we have no more tasks left due to dynamic disenrollment,
1070 // shut down the thread since we don't currently support dynamic enrollment
1071 if (PeriodicTask::num_tasks() == 0) {
1072 _should_terminate = true;
1073 }
1074 }
1075
1076 // Signal that it is terminated
1077 {
1078 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1079 _watcher_thread = NULL;
1080 Terminator_lock->notify();
1081 }
1082
1083 // Thread destructor usually does this..
1084 ThreadLocalStorage::set_thread(NULL);
1085 }
1086
1087 void WatcherThread::start() {
1088 if (watcher_thread() == NULL) {
1089 _should_terminate = false;
1090 // Create the single instance of WatcherThread
1091 new WatcherThread();
1092 }
1093 }
1094
1095 void WatcherThread::stop() {
1096 // it is ok to take late safepoints here, if needed
1097 MutexLocker mu(Terminator_lock);
1098 _should_terminate = true;
1099 while(watcher_thread() != NULL) {
1100 // This wait should make safepoint checks, wait without a timeout,
1101 // and wait as a suspend-equivalent condition.
1102 //
1103 // Note: If the FlatProfiler is running, then this thread is waiting
1104 // for the WatcherThread to terminate and the WatcherThread, via the
1105 // FlatProfiler task, is waiting for the external suspend request on
1106 // this thread to complete. wait_for_ext_suspend_completion() will
1107 // eventually timeout, but that takes time. Making this wait a
1108 // suspend-equivalent condition solves that timeout problem.
1109 //
1110 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1111 Mutex::_as_suspend_equivalent_flag);
1112 }
1113 }
1114
1115 void WatcherThread::print_on(outputStream* st) const {
1116 st->print("\"%s\" ", name());
1117 Thread::print_on(st);
1118 st->cr();
1119 }
1120
1121 // ======= JavaThread ========
1122
1123 // A JavaThread is a normal Java thread
1124
1125 void JavaThread::initialize() {
1126 // Initialize fields
1127
1128 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1129 set_claimed_par_id(-1);
1130
1131 set_saved_exception_pc(NULL);
1132 set_threadObj(NULL);
1133 _anchor.clear();
1134 set_entry_point(NULL);
1135 set_jni_functions(jni_functions());
1136 set_callee_target(NULL);
1137 set_vm_result(NULL);
1138 set_vm_result_2(NULL);
1139 set_vframe_array_head(NULL);
1140 set_vframe_array_last(NULL);
1141 set_deferred_locals(NULL);
1142 set_deopt_mark(NULL);
1143 clear_must_deopt_id();
1144 set_monitor_chunks(NULL);
1145 set_next(NULL);
1146 set_thread_state(_thread_new);
1147 _terminated = _not_terminated;
1148 _privileged_stack_top = NULL;
1149 _array_for_gc = NULL;
1150 _suspend_equivalent = false;
1151 _in_deopt_handler = 0;
1152 _doing_unsafe_access = false;
1153 _stack_guard_state = stack_guard_unused;
1154 _exception_oop = NULL;
1155 _exception_pc = 0;
1156 _exception_handler_pc = 0;
1157 _exception_stack_size = 0;
1158 _jvmti_thread_state= NULL;
1159 _jvmti_get_loaded_classes_closure = NULL;
1160 _interp_only_mode = 0;
1161 _special_runtime_exit_condition = _no_async_condition;
1162 _pending_async_exception = NULL;
1163 _is_compiling = false;
1164 _thread_stat = NULL;
1165 _thread_stat = new ThreadStatistics();
1166 _blocked_on_compilation = false;
1167 _jni_active_critical = 0;
1168 _do_not_unlock_if_synchronized = false;
1169 _cached_monitor_info = NULL;
1170 _parker = Parker::Allocate(this) ;
1171
1172 #ifndef PRODUCT
1173 _jmp_ring_index = 0;
1174 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1175 record_jump(NULL, NULL, NULL, 0);
1176 }
1177 #endif /* PRODUCT */
1178
1179 set_thread_profiler(NULL);
1180 if (FlatProfiler::is_active()) {
1181 // This is where we would decide to either give each thread it's own profiler
1182 // or use one global one from FlatProfiler,
1183 // or up to some count of the number of profiled threads, etc.
1184 ThreadProfiler* pp = new ThreadProfiler();
1185 pp->engage();
1186 set_thread_profiler(pp);
1187 }
1188
1189 // Setup safepoint state info for this thread
1190 ThreadSafepointState::create(this);
1191
1192 debug_only(_java_call_counter = 0);
1193
1194 // JVMTI PopFrame support
1195 _popframe_condition = popframe_inactive;
1196 _popframe_preserved_args = NULL;
1197 _popframe_preserved_args_size = 0;
1198
1199 pd_initialize();
1200 }
1201
1202 #ifndef SERIALGC
1203 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1204 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1205 #endif // !SERIALGC
1206
1207 JavaThread::JavaThread(bool is_attaching) :
1208 Thread()
1209 #ifndef SERIALGC
1210 , _satb_mark_queue(&_satb_mark_queue_set),
1211 _dirty_card_queue(&_dirty_card_queue_set)
1212 #endif // !SERIALGC
1213 {
1214 initialize();
1215 _is_attaching = is_attaching;
1216 }
1217
1218 bool JavaThread::reguard_stack(address cur_sp) {
1219 if (_stack_guard_state != stack_guard_yellow_disabled) {
1220 return true; // Stack already guarded or guard pages not needed.
1221 }
1222
1223 if (register_stack_overflow()) {
1224 // For those architectures which have separate register and
1225 // memory stacks, we must check the register stack to see if
1226 // it has overflowed.
1227 return false;
1228 }
1229
1230 // Java code never executes within the yellow zone: the latter is only
1231 // there to provoke an exception during stack banging. If java code
1232 // is executing there, either StackShadowPages should be larger, or
1233 // some exception code in c1, c2 or the interpreter isn't unwinding
1234 // when it should.
1235 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1236
1237 enable_stack_yellow_zone();
1238 return true;
1239 }
1240
1241 bool JavaThread::reguard_stack(void) {
1242 return reguard_stack(os::current_stack_pointer());
1243 }
1244
1245
1246 void JavaThread::block_if_vm_exited() {
1247 if (_terminated == _vm_exited) {
1248 // _vm_exited is set at safepoint, and Threads_lock is never released
1249 // we will block here forever
1250 Threads_lock->lock_without_safepoint_check();
1251 ShouldNotReachHere();
1252 }
1253 }
1254
1255
1256 // Remove this ifdef when C1 is ported to the compiler interface.
1257 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1258
1259 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1260 Thread()
1261 #ifndef SERIALGC
1262 , _satb_mark_queue(&_satb_mark_queue_set),
1263 _dirty_card_queue(&_dirty_card_queue_set)
1264 #endif // !SERIALGC
1265 {
1266 if (TraceThreadEvents) {
1267 tty->print_cr("creating thread %p", this);
1268 }
1269 initialize();
1270 _is_attaching = false;
1271 set_entry_point(entry_point);
1272 // Create the native thread itself.
1273 // %note runtime_23
1274 os::ThreadType thr_type = os::java_thread;
1275 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1276 os::java_thread;
1277 os::create_thread(this, thr_type, stack_sz);
1278
1279 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1280 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1281 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1282 // the exception consists of creating the exception object & initializing it, initialization
1283 // will leave the VM via a JavaCall and then all locks must be unlocked).
1284 //
1285 // The thread is still suspended when we reach here. Thread must be explicit started
1286 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1287 // by calling Threads:add. The reason why this is not done here, is because the thread
1288 // object must be fully initialized (take a look at JVM_Start)
1289 }
1290
1291 JavaThread::~JavaThread() {
1292 if (TraceThreadEvents) {
1293 tty->print_cr("terminate thread %p", this);
1294 }
1295
1296 // JSR166 -- return the parker to the free list
1297 Parker::Release(_parker);
1298 _parker = NULL ;
1299
1300 // Free any remaining previous UnrollBlock
1301 vframeArray* old_array = vframe_array_last();
1302
1303 if (old_array != NULL) {
1304 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1305 old_array->set_unroll_block(NULL);
1306 delete old_info;
1307 delete old_array;
1308 }
1309
1310 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1311 if (deferred != NULL) {
1312 // This can only happen if thread is destroyed before deoptimization occurs.
1313 assert(deferred->length() != 0, "empty array!");
1314 do {
1315 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1316 deferred->remove_at(0);
1317 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1318 delete dlv;
1319 } while (deferred->length() != 0);
1320 delete deferred;
1321 }
1322
1323 // All Java related clean up happens in exit
1324 ThreadSafepointState::destroy(this);
1325 if (_thread_profiler != NULL) delete _thread_profiler;
1326 if (_thread_stat != NULL) delete _thread_stat;
1327 }
1328
1329
1330 // The first routine called by a new Java thread
1331 void JavaThread::run() {
1332 // initialize thread-local alloc buffer related fields
1333 this->initialize_tlab();
1334
1335 // used to test validitity of stack trace backs
1336 this->record_base_of_stack_pointer();
1337
1338 // Record real stack base and size.
1339 this->record_stack_base_and_size();
1340
1341 // Initialize thread local storage; set before calling MutexLocker
1342 this->initialize_thread_local_storage();
1343
1344 this->create_stack_guard_pages();
1345
1346 // Thread is now sufficient initialized to be handled by the safepoint code as being
1347 // in the VM. Change thread state from _thread_new to _thread_in_vm
1348 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1349
1350 assert(JavaThread::current() == this, "sanity check");
1351 assert(!Thread::current()->owns_locks(), "sanity check");
1352
1353 DTRACE_THREAD_PROBE(start, this);
1354
1355 // This operation might block. We call that after all safepoint checks for a new thread has
1356 // been completed.
1357 this->set_active_handles(JNIHandleBlock::allocate_block());
1358
1359 if (JvmtiExport::should_post_thread_life()) {
1360 JvmtiExport::post_thread_start(this);
1361 }
1362
1363 // We call another function to do the rest so we are sure that the stack addresses used
1364 // from there will be lower than the stack base just computed
1365 thread_main_inner();
1366
1367 // Note, thread is no longer valid at this point!
1368 }
1369
1370
1371 void JavaThread::thread_main_inner() {
1372 assert(JavaThread::current() == this, "sanity check");
1373 assert(this->threadObj() != NULL, "just checking");
1374
1375 // Execute thread entry point. If this thread is being asked to restart,
1376 // or has been stopped before starting, do not reexecute entry point.
1377 // Note: Due to JVM_StopThread we can have pending exceptions already!
1378 if (!this->has_pending_exception() && !java_lang_Thread::is_stillborn(this->threadObj())) {
1379 // enter the thread's entry point only if we have no pending exceptions
1380 HandleMark hm(this);
1381 this->entry_point()(this, this);
1382 }
1383
1384 DTRACE_THREAD_PROBE(stop, this);
1385
1386 this->exit(false);
1387 delete this;
1388 }
1389
1390
1391 static void ensure_join(JavaThread* thread) {
1392 // We do not need to grap the Threads_lock, since we are operating on ourself.
1393 Handle threadObj(thread, thread->threadObj());
1394 assert(threadObj.not_null(), "java thread object must exist");
1395 ObjectLocker lock(threadObj, thread);
1396 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1397 thread->clear_pending_exception();
1398 // It is of profound importance that we set the stillborn bit and reset the thread object,
1399 // before we do the notify. Since, changing these two variable will make JVM_IsAlive return
1400 // false. So in case another thread is doing a join on this thread , it will detect that the thread
1401 // is dead when it gets notified.
1402 java_lang_Thread::set_stillborn(threadObj());
1403 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1404 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1405 java_lang_Thread::set_thread(threadObj(), NULL);
1406 lock.notify_all(thread);
1407 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1408 thread->clear_pending_exception();
1409 }
1410
1411
1412 // For any new cleanup additions, please check to see if they need to be applied to
1413 // cleanup_failed_attach_current_thread as well.
1414 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1415 assert(this == JavaThread::current(), "thread consistency check");
1416 if (!InitializeJavaLangSystem) return;
1417
1418 HandleMark hm(this);
1419 Handle uncaught_exception(this, this->pending_exception());
1420 this->clear_pending_exception();
1421 Handle threadObj(this, this->threadObj());
1422 assert(threadObj.not_null(), "Java thread object should be created");
1423
1424 if (get_thread_profiler() != NULL) {
1425 get_thread_profiler()->disengage();
1426 ResourceMark rm;
1427 get_thread_profiler()->print(get_thread_name());
1428 }
1429
1430
1431 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1432 {
1433 EXCEPTION_MARK;
1434
1435 CLEAR_PENDING_EXCEPTION;
1436 }
1437 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1438 // has to be fixed by a runtime query method
1439 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1440 // JSR-166: change call from from ThreadGroup.uncaughtException to
1441 // java.lang.Thread.dispatchUncaughtException
1442 if (uncaught_exception.not_null()) {
1443 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1444 Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT",
1445 (address)uncaught_exception(), (address)threadObj(), (address)group());
1446 {
1447 EXCEPTION_MARK;
1448 // Check if the method Thread.dispatchUncaughtException() exists. If so
1449 // call it. Otherwise we have an older library without the JSR-166 changes,
1450 // so call ThreadGroup.uncaughtException()
1451 KlassHandle recvrKlass(THREAD, threadObj->klass());
1452 CallInfo callinfo;
1453 KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass());
1454 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1455 vmSymbolHandles::dispatchUncaughtException_name(),
1456 vmSymbolHandles::throwable_void_signature(),
1457 KlassHandle(), false, false, THREAD);
1458 CLEAR_PENDING_EXCEPTION;
1459 methodHandle method = callinfo.selected_method();
1460 if (method.not_null()) {
1461 JavaValue result(T_VOID);
1462 JavaCalls::call_virtual(&result,
1463 threadObj, thread_klass,
1464 vmSymbolHandles::dispatchUncaughtException_name(),
1465 vmSymbolHandles::throwable_void_signature(),
1466 uncaught_exception,
1467 THREAD);
1468 } else {
1469 KlassHandle thread_group(THREAD, SystemDictionary::threadGroup_klass());
1470 JavaValue result(T_VOID);
1471 JavaCalls::call_virtual(&result,
1472 group, thread_group,
1473 vmSymbolHandles::uncaughtException_name(),
1474 vmSymbolHandles::thread_throwable_void_signature(),
1475 threadObj, // Arg 1
1476 uncaught_exception, // Arg 2
1477 THREAD);
1478 }
1479 CLEAR_PENDING_EXCEPTION;
1480 }
1481 }
1482
1483 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1484 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1485 // is deprecated anyhow.
1486 { int count = 3;
1487 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1488 EXCEPTION_MARK;
1489 JavaValue result(T_VOID);
1490 KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass());
1491 JavaCalls::call_virtual(&result,
1492 threadObj, thread_klass,
1493 vmSymbolHandles::exit_method_name(),
1494 vmSymbolHandles::void_method_signature(),
1495 THREAD);
1496 CLEAR_PENDING_EXCEPTION;
1497 }
1498 }
1499
1500 // notify JVMTI
1501 if (JvmtiExport::should_post_thread_life()) {
1502 JvmtiExport::post_thread_end(this);
1503 }
1504
1505 // We have notified the agents that we are exiting, before we go on,
1506 // we must check for a pending external suspend request and honor it
1507 // in order to not surprise the thread that made the suspend request.
1508 while (true) {
1509 {
1510 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1511 if (!is_external_suspend()) {
1512 set_terminated(_thread_exiting);
1513 ThreadService::current_thread_exiting(this);
1514 break;
1515 }
1516 // Implied else:
1517 // Things get a little tricky here. We have a pending external
1518 // suspend request, but we are holding the SR_lock so we
1519 // can't just self-suspend. So we temporarily drop the lock
1520 // and then self-suspend.
1521 }
1522
1523 ThreadBlockInVM tbivm(this);
1524 java_suspend_self();
1525
1526 // We're done with this suspend request, but we have to loop around
1527 // and check again. Eventually we will get SR_lock without a pending
1528 // external suspend request and will be able to mark ourselves as
1529 // exiting.
1530 }
1531 // no more external suspends are allowed at this point
1532 } else {
1533 // before_exit() has already posted JVMTI THREAD_END events
1534 }
1535
1536 // Notify waiters on thread object. This has to be done after exit() is called
1537 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1538 // group should have the destroyed bit set before waiters are notified).
1539 ensure_join(this);
1540 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1541
1542 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1543 // held by this thread must be released. A detach operation must only
1544 // get here if there are no Java frames on the stack. Therefore, any
1545 // owned monitors at this point MUST be JNI-acquired monitors which are
1546 // pre-inflated and in the monitor cache.
1547 //
1548 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1549 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1550 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1551 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1552 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1553 }
1554
1555 // These things needs to be done while we are still a Java Thread. Make sure that thread
1556 // is in a consistent state, in case GC happens
1557 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1558
1559 if (active_handles() != NULL) {
1560 JNIHandleBlock* block = active_handles();
1561 set_active_handles(NULL);
1562 JNIHandleBlock::release_block(block);
1563 }
1564
1565 if (free_handle_block() != NULL) {
1566 JNIHandleBlock* block = free_handle_block();
1567 set_free_handle_block(NULL);
1568 JNIHandleBlock::release_block(block);
1569 }
1570
1571 // These have to be removed while this is still a valid thread.
1572 remove_stack_guard_pages();
1573
1574 if (UseTLAB) {
1575 tlab().make_parsable(true); // retire TLAB
1576 }
1577
1578 if (jvmti_thread_state() != NULL) {
1579 JvmtiExport::cleanup_thread(this);
1580 }
1581
1582 #ifndef SERIALGC
1583 // We must flush G1-related buffers before removing a thread from
1584 // the list of active threads.
1585 if (UseG1GC) {
1586 flush_barrier_queues();
1587 }
1588 #endif
1589
1590 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1591 Threads::remove(this);
1592 }
1593
1594 #ifndef SERIALGC
1595 // Flush G1-related queues.
1596 void JavaThread::flush_barrier_queues() {
1597 satb_mark_queue().flush();
1598 dirty_card_queue().flush();
1599 }
1600 #endif
1601
1602 void JavaThread::cleanup_failed_attach_current_thread() {
1603 if (get_thread_profiler() != NULL) {
1604 get_thread_profiler()->disengage();
1605 ResourceMark rm;
1606 get_thread_profiler()->print(get_thread_name());
1607 }
1608
1609 if (active_handles() != NULL) {
1610 JNIHandleBlock* block = active_handles();
1611 set_active_handles(NULL);
1612 JNIHandleBlock::release_block(block);
1613 }
1614
1615 if (free_handle_block() != NULL) {
1616 JNIHandleBlock* block = free_handle_block();
1617 set_free_handle_block(NULL);
1618 JNIHandleBlock::release_block(block);
1619 }
1620
1621 if (UseTLAB) {
1622 tlab().make_parsable(true); // retire TLAB, if any
1623 }
1624
1625 #ifndef SERIALGC
1626 if (UseG1GC) {
1627 flush_barrier_queues();
1628 }
1629 #endif
1630
1631 Threads::remove(this);
1632 delete this;
1633 }
1634
1635
1636
1637
1638 JavaThread* JavaThread::active() {
1639 Thread* thread = ThreadLocalStorage::thread();
1640 assert(thread != NULL, "just checking");
1641 if (thread->is_Java_thread()) {
1642 return (JavaThread*) thread;
1643 } else {
1644 assert(thread->is_VM_thread(), "this must be a vm thread");
1645 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1646 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1647 assert(ret->is_Java_thread(), "must be a Java thread");
1648 return ret;
1649 }
1650 }
1651
1652 bool JavaThread::is_lock_owned(address adr) const {
1653 if (Thread::is_lock_owned(adr)) return true;
1654
1655 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1656 if (chunk->contains(adr)) return true;
1657 }
1658
1659 return false;
1660 }
1661
1662
1663 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1664 chunk->set_next(monitor_chunks());
1665 set_monitor_chunks(chunk);
1666 }
1667
1668 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1669 guarantee(monitor_chunks() != NULL, "must be non empty");
1670 if (monitor_chunks() == chunk) {
1671 set_monitor_chunks(chunk->next());
1672 } else {
1673 MonitorChunk* prev = monitor_chunks();
1674 while (prev->next() != chunk) prev = prev->next();
1675 prev->set_next(chunk->next());
1676 }
1677 }
1678
1679 // JVM support.
1680
1681 // Note: this function shouldn't block if it's called in
1682 // _thread_in_native_trans state (such as from
1683 // check_special_condition_for_native_trans()).
1684 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1685
1686 if (has_last_Java_frame() && has_async_condition()) {
1687 // If we are at a polling page safepoint (not a poll return)
1688 // then we must defer async exception because live registers
1689 // will be clobbered by the exception path. Poll return is
1690 // ok because the call we a returning from already collides
1691 // with exception handling registers and so there is no issue.
1692 // (The exception handling path kills call result registers but
1693 // this is ok since the exception kills the result anyway).
1694
1695 if (is_at_poll_safepoint()) {
1696 // if the code we are returning to has deoptimized we must defer
1697 // the exception otherwise live registers get clobbered on the
1698 // exception path before deoptimization is able to retrieve them.
1699 //
1700 RegisterMap map(this, false);
1701 frame caller_fr = last_frame().sender(&map);
1702 assert(caller_fr.is_compiled_frame(), "what?");
1703 if (caller_fr.is_deoptimized_frame()) {
1704 if (TraceExceptions) {
1705 ResourceMark rm;
1706 tty->print_cr("deferred async exception at compiled safepoint");
1707 }
1708 return;
1709 }
1710 }
1711 }
1712
1713 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
1714 if (condition == _no_async_condition) {
1715 // Conditions have changed since has_special_runtime_exit_condition()
1716 // was called:
1717 // - if we were here only because of an external suspend request,
1718 // then that was taken care of above (or cancelled) so we are done
1719 // - if we were here because of another async request, then it has
1720 // been cleared between the has_special_runtime_exit_condition()
1721 // and now so again we are done
1722 return;
1723 }
1724
1725 // Check for pending async. exception
1726 if (_pending_async_exception != NULL) {
1727 // Only overwrite an already pending exception, if it is not a threadDeath.
1728 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::threaddeath_klass())) {
1729
1730 // We cannot call Exceptions::_throw(...) here because we cannot block
1731 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
1732
1733 if (TraceExceptions) {
1734 ResourceMark rm;
1735 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
1736 if (has_last_Java_frame() ) {
1737 frame f = last_frame();
1738 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
1739 }
1740 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1741 }
1742 _pending_async_exception = NULL;
1743 clear_has_async_exception();
1744 }
1745 }
1746
1747 if (check_unsafe_error &&
1748 condition == _async_unsafe_access_error && !has_pending_exception()) {
1749 condition = _no_async_condition; // done
1750 switch (thread_state()) {
1751 case _thread_in_vm:
1752 {
1753 JavaThread* THREAD = this;
1754 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1755 }
1756 case _thread_in_native:
1757 {
1758 ThreadInVMfromNative tiv(this);
1759 JavaThread* THREAD = this;
1760 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1761 }
1762 case _thread_in_Java:
1763 {
1764 ThreadInVMfromJava tiv(this);
1765 JavaThread* THREAD = this;
1766 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
1767 }
1768 default:
1769 ShouldNotReachHere();
1770 }
1771 }
1772
1773 assert(condition == _no_async_condition || has_pending_exception() ||
1774 (!check_unsafe_error && condition == _async_unsafe_access_error),
1775 "must have handled the async condition, if no exception");
1776 }
1777
1778 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
1779 //
1780 // Check for pending external suspend. Internal suspend requests do
1781 // not use handle_special_runtime_exit_condition().
1782 // If JNIEnv proxies are allowed, don't self-suspend if the target
1783 // thread is not the current thread. In older versions of jdbx, jdbx
1784 // threads could call into the VM with another thread's JNIEnv so we
1785 // can be here operating on behalf of a suspended thread (4432884).
1786 bool do_self_suspend = is_external_suspend_with_lock();
1787 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
1788 //
1789 // Because thread is external suspended the safepoint code will count
1790 // thread as at a safepoint. This can be odd because we can be here
1791 // as _thread_in_Java which would normally transition to _thread_blocked
1792 // at a safepoint. We would like to mark the thread as _thread_blocked
1793 // before calling java_suspend_self like all other callers of it but
1794 // we must then observe proper safepoint protocol. (We can't leave
1795 // _thread_blocked with a safepoint in progress). However we can be
1796 // here as _thread_in_native_trans so we can't use a normal transition
1797 // constructor/destructor pair because they assert on that type of
1798 // transition. We could do something like:
1799 //
1800 // JavaThreadState state = thread_state();
1801 // set_thread_state(_thread_in_vm);
1802 // {
1803 // ThreadBlockInVM tbivm(this);
1804 // java_suspend_self()
1805 // }
1806 // set_thread_state(_thread_in_vm_trans);
1807 // if (safepoint) block;
1808 // set_thread_state(state);
1809 //
1810 // but that is pretty messy. Instead we just go with the way the
1811 // code has worked before and note that this is the only path to
1812 // java_suspend_self that doesn't put the thread in _thread_blocked
1813 // mode.
1814
1815 frame_anchor()->make_walkable(this);
1816 java_suspend_self();
1817
1818 // We might be here for reasons in addition to the self-suspend request
1819 // so check for other async requests.
1820 }
1821
1822 if (check_asyncs) {
1823 check_and_handle_async_exceptions();
1824 }
1825 }
1826
1827 void JavaThread::send_thread_stop(oop java_throwable) {
1828 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
1829 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
1830 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
1831
1832 // Do not throw asynchronous exceptions against the compiler thread
1833 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
1834 if (is_Compiler_thread()) return;
1835
1836 // This is a change from JDK 1.1, but JDK 1.2 will also do it:
1837 if (java_throwable->is_a(SystemDictionary::threaddeath_klass())) {
1838 java_lang_Thread::set_stillborn(threadObj());
1839 }
1840
1841 {
1842 // Actually throw the Throwable against the target Thread - however
1843 // only if there is no thread death exception installed already.
1844 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::threaddeath_klass())) {
1845 // If the topmost frame is a runtime stub, then we are calling into
1846 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1847 // must deoptimize the caller before continuing, as the compiled exception handler table
1848 // may not be valid
1849 if (has_last_Java_frame()) {
1850 frame f = last_frame();
1851 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
1852 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
1853 RegisterMap reg_map(this, UseBiasedLocking);
1854 frame compiled_frame = f.sender(®_map);
1855 if (compiled_frame.can_be_deoptimized()) {
1856 Deoptimization::deoptimize(this, compiled_frame, ®_map);
1857 }
1858 }
1859 }
1860
1861 // Set async. pending exception in thread.
1862 set_pending_async_exception(java_throwable);
1863
1864 if (TraceExceptions) {
1865 ResourceMark rm;
1866 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1867 }
1868 // for AbortVMOnException flag
1869 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
1870 }
1871 }
1872
1873
1874 // Interrupt thread so it will wake up from a potential wait()
1875 Thread::interrupt(this);
1876 }
1877
1878 // External suspension mechanism.
1879 //
1880 // Tell the VM to suspend a thread when ever it knows that it does not hold on
1881 // to any VM_locks and it is at a transition
1882 // Self-suspension will happen on the transition out of the vm.
1883 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
1884 //
1885 // Guarantees on return:
1886 // + Target thread will not execute any new bytecode (that's why we need to
1887 // force a safepoint)
1888 // + Target thread will not enter any new monitors
1889 //
1890 void JavaThread::java_suspend() {
1891 { MutexLocker mu(Threads_lock);
1892 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
1893 return;
1894 }
1895 }
1896
1897 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1898 if (!is_external_suspend()) {
1899 // a racing resume has cancelled us; bail out now
1900 return;
1901 }
1902
1903 // suspend is done
1904 uint32_t debug_bits = 0;
1905 // Warning: is_ext_suspend_completed() may temporarily drop the
1906 // SR_lock to allow the thread to reach a stable thread state if
1907 // it is currently in a transient thread state.
1908 if (is_ext_suspend_completed(false /* !called_by_wait */,
1909 SuspendRetryDelay, &debug_bits) ) {
1910 return;
1911 }
1912 }
1913
1914 VM_ForceSafepoint vm_suspend;
1915 VMThread::execute(&vm_suspend);
1916 }
1917
1918 // Part II of external suspension.
1919 // A JavaThread self suspends when it detects a pending external suspend
1920 // request. This is usually on transitions. It is also done in places
1921 // where continuing to the next transition would surprise the caller,
1922 // e.g., monitor entry.
1923 //
1924 // Returns the number of times that the thread self-suspended.
1925 //
1926 // Note: DO NOT call java_suspend_self() when you just want to block current
1927 // thread. java_suspend_self() is the second stage of cooperative
1928 // suspension for external suspend requests and should only be used
1929 // to complete an external suspend request.
1930 //
1931 int JavaThread::java_suspend_self() {
1932 int ret = 0;
1933
1934 // we are in the process of exiting so don't suspend
1935 if (is_exiting()) {
1936 clear_external_suspend();
1937 return ret;
1938 }
1939
1940 assert(_anchor.walkable() ||
1941 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
1942 "must have walkable stack");
1943
1944 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1945
1946 assert(!this->is_ext_suspended(),
1947 "a thread trying to self-suspend should not already be suspended");
1948
1949 if (this->is_suspend_equivalent()) {
1950 // If we are self-suspending as a result of the lifting of a
1951 // suspend equivalent condition, then the suspend_equivalent
1952 // flag is not cleared until we set the ext_suspended flag so
1953 // that wait_for_ext_suspend_completion() returns consistent
1954 // results.
1955 this->clear_suspend_equivalent();
1956 }
1957
1958 // A racing resume may have cancelled us before we grabbed SR_lock
1959 // above. Or another external suspend request could be waiting for us
1960 // by the time we return from SR_lock()->wait(). The thread
1961 // that requested the suspension may already be trying to walk our
1962 // stack and if we return now, we can change the stack out from under
1963 // it. This would be a "bad thing (TM)" and cause the stack walker
1964 // to crash. We stay self-suspended until there are no more pending
1965 // external suspend requests.
1966 while (is_external_suspend()) {
1967 ret++;
1968 this->set_ext_suspended();
1969
1970 // _ext_suspended flag is cleared by java_resume()
1971 while (is_ext_suspended()) {
1972 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
1973 }
1974 }
1975
1976 return ret;
1977 }
1978
1979 #ifdef ASSERT
1980 // verify the JavaThread has not yet been published in the Threads::list, and
1981 // hence doesn't need protection from concurrent access at this stage
1982 void JavaThread::verify_not_published() {
1983 if (!Threads_lock->owned_by_self()) {
1984 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
1985 assert( !Threads::includes(this),
1986 "java thread shouldn't have been published yet!");
1987 }
1988 else {
1989 assert( !Threads::includes(this),
1990 "java thread shouldn't have been published yet!");
1991 }
1992 }
1993 #endif
1994
1995 // Slow path when the native==>VM/Java barriers detect a safepoint is in
1996 // progress or when _suspend_flags is non-zero.
1997 // Current thread needs to self-suspend if there is a suspend request and/or
1998 // block if a safepoint is in progress.
1999 // Async exception ISN'T checked.
2000 // Note only the ThreadInVMfromNative transition can call this function
2001 // directly and when thread state is _thread_in_native_trans
2002 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2003 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2004
2005 JavaThread *curJT = JavaThread::current();
2006 bool do_self_suspend = thread->is_external_suspend();
2007
2008 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2009
2010 // If JNIEnv proxies are allowed, don't self-suspend if the target
2011 // thread is not the current thread. In older versions of jdbx, jdbx
2012 // threads could call into the VM with another thread's JNIEnv so we
2013 // can be here operating on behalf of a suspended thread (4432884).
2014 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2015 JavaThreadState state = thread->thread_state();
2016
2017 // We mark this thread_blocked state as a suspend-equivalent so
2018 // that a caller to is_ext_suspend_completed() won't be confused.
2019 // The suspend-equivalent state is cleared by java_suspend_self().
2020 thread->set_suspend_equivalent();
2021
2022 // If the safepoint code sees the _thread_in_native_trans state, it will
2023 // wait until the thread changes to other thread state. There is no
2024 // guarantee on how soon we can obtain the SR_lock and complete the
2025 // self-suspend request. It would be a bad idea to let safepoint wait for
2026 // too long. Temporarily change the state to _thread_blocked to
2027 // let the VM thread know that this thread is ready for GC. The problem
2028 // of changing thread state is that safepoint could happen just after
2029 // java_suspend_self() returns after being resumed, and VM thread will
2030 // see the _thread_blocked state. We must check for safepoint
2031 // after restoring the state and make sure we won't leave while a safepoint
2032 // is in progress.
2033 thread->set_thread_state(_thread_blocked);
2034 thread->java_suspend_self();
2035 thread->set_thread_state(state);
2036 // Make sure new state is seen by VM thread
2037 if (os::is_MP()) {
2038 if (UseMembar) {
2039 // Force a fence between the write above and read below
2040 OrderAccess::fence();
2041 } else {
2042 // Must use this rather than serialization page in particular on Windows
2043 InterfaceSupport::serialize_memory(thread);
2044 }
2045 }
2046 }
2047
2048 if (SafepointSynchronize::do_call_back()) {
2049 // If we are safepointing, then block the caller which may not be
2050 // the same as the target thread (see above).
2051 SafepointSynchronize::block(curJT);
2052 }
2053
2054 if (thread->is_deopt_suspend()) {
2055 thread->clear_deopt_suspend();
2056 RegisterMap map(thread, false);
2057 frame f = thread->last_frame();
2058 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2059 f = f.sender(&map);
2060 }
2061 if (f.id() == thread->must_deopt_id()) {
2062 thread->clear_must_deopt_id();
2063 // Since we know we're safe to deopt the current state is a safe state
2064 f.deoptimize(thread, true);
2065 } else {
2066 fatal("missed deoptimization!");
2067 }
2068 }
2069 }
2070
2071 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2072 // progress or when _suspend_flags is non-zero.
2073 // Current thread needs to self-suspend if there is a suspend request and/or
2074 // block if a safepoint is in progress.
2075 // Also check for pending async exception (not including unsafe access error).
2076 // Note only the native==>VM/Java barriers can call this function and when
2077 // thread state is _thread_in_native_trans.
2078 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2079 check_safepoint_and_suspend_for_native_trans(thread);
2080
2081 if (thread->has_async_exception()) {
2082 // We are in _thread_in_native_trans state, don't handle unsafe
2083 // access error since that may block.
2084 thread->check_and_handle_async_exceptions(false);
2085 }
2086 }
2087
2088 // We need to guarantee the Threads_lock here, since resumes are not
2089 // allowed during safepoint synchronization
2090 // Can only resume from an external suspension
2091 void JavaThread::java_resume() {
2092 assert_locked_or_safepoint(Threads_lock);
2093
2094 // Sanity check: thread is gone, has started exiting or the thread
2095 // was not externally suspended.
2096 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2097 return;
2098 }
2099
2100 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2101
2102 clear_external_suspend();
2103
2104 if (is_ext_suspended()) {
2105 clear_ext_suspended();
2106 SR_lock()->notify_all();
2107 }
2108 }
2109
2110 void JavaThread::create_stack_guard_pages() {
2111 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2112 address low_addr = stack_base() - stack_size();
2113 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2114
2115 int allocate = os::allocate_stack_guard_pages();
2116 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2117
2118 if (allocate && !os::commit_memory((char *) low_addr, len)) {
2119 warning("Attempt to allocate stack guard pages failed.");
2120 return;
2121 }
2122
2123 if (os::guard_memory((char *) low_addr, len)) {
2124 _stack_guard_state = stack_guard_enabled;
2125 } else {
2126 warning("Attempt to protect stack guard pages failed.");
2127 if (os::uncommit_memory((char *) low_addr, len)) {
2128 warning("Attempt to deallocate stack guard pages failed.");
2129 }
2130 }
2131 }
2132
2133 void JavaThread::remove_stack_guard_pages() {
2134 if (_stack_guard_state == stack_guard_unused) return;
2135 address low_addr = stack_base() - stack_size();
2136 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2137
2138 if (os::allocate_stack_guard_pages()) {
2139 if (os::uncommit_memory((char *) low_addr, len)) {
2140 _stack_guard_state = stack_guard_unused;
2141 } else {
2142 warning("Attempt to deallocate stack guard pages failed.");
2143 }
2144 } else {
2145 if (_stack_guard_state == stack_guard_unused) return;
2146 if (os::unguard_memory((char *) low_addr, len)) {
2147 _stack_guard_state = stack_guard_unused;
2148 } else {
2149 warning("Attempt to unprotect stack guard pages failed.");
2150 }
2151 }
2152 }
2153
2154 void JavaThread::enable_stack_yellow_zone() {
2155 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2156 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2157
2158 // The base notation is from the stacks point of view, growing downward.
2159 // We need to adjust it to work correctly with guard_memory()
2160 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2161
2162 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2163 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2164
2165 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2166 _stack_guard_state = stack_guard_enabled;
2167 } else {
2168 warning("Attempt to guard stack yellow zone failed.");
2169 }
2170 enable_register_stack_guard();
2171 }
2172
2173 void JavaThread::disable_stack_yellow_zone() {
2174 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2175 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2176
2177 // Simply return if called for a thread that does not use guard pages.
2178 if (_stack_guard_state == stack_guard_unused) return;
2179
2180 // The base notation is from the stacks point of view, growing downward.
2181 // We need to adjust it to work correctly with guard_memory()
2182 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2183
2184 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2185 _stack_guard_state = stack_guard_yellow_disabled;
2186 } else {
2187 warning("Attempt to unguard stack yellow zone failed.");
2188 }
2189 disable_register_stack_guard();
2190 }
2191
2192 void JavaThread::enable_stack_red_zone() {
2193 // The base notation is from the stacks point of view, growing downward.
2194 // We need to adjust it to work correctly with guard_memory()
2195 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2196 address base = stack_red_zone_base() - stack_red_zone_size();
2197
2198 guarantee(base < stack_base(),"Error calculating stack red zone");
2199 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2200
2201 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2202 warning("Attempt to guard stack red zone failed.");
2203 }
2204 }
2205
2206 void JavaThread::disable_stack_red_zone() {
2207 // The base notation is from the stacks point of view, growing downward.
2208 // We need to adjust it to work correctly with guard_memory()
2209 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2210 address base = stack_red_zone_base() - stack_red_zone_size();
2211 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2212 warning("Attempt to unguard stack red zone failed.");
2213 }
2214 }
2215
2216 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2217 // ignore is there is no stack
2218 if (!has_last_Java_frame()) return;
2219 // traverse the stack frames. Starts from top frame.
2220 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2221 frame* fr = fst.current();
2222 f(fr, fst.register_map());
2223 }
2224 }
2225
2226
2227 #ifndef PRODUCT
2228 // Deoptimization
2229 // Function for testing deoptimization
2230 void JavaThread::deoptimize() {
2231 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2232 StackFrameStream fst(this, UseBiasedLocking);
2233 bool deopt = false; // Dump stack only if a deopt actually happens.
2234 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2235 // Iterate over all frames in the thread and deoptimize
2236 for(; !fst.is_done(); fst.next()) {
2237 if(fst.current()->can_be_deoptimized()) {
2238
2239 if (only_at) {
2240 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2241 // consists of comma or carriage return separated numbers so
2242 // search for the current bci in that string.
2243 address pc = fst.current()->pc();
2244 nmethod* nm = (nmethod*) fst.current()->cb();
2245 ScopeDesc* sd = nm->scope_desc_at( pc);
2246 char buffer[8];
2247 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2248 size_t len = strlen(buffer);
2249 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2250 while (found != NULL) {
2251 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2252 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2253 // Check that the bci found is bracketed by terminators.
2254 break;
2255 }
2256 found = strstr(found + 1, buffer);
2257 }
2258 if (!found) {
2259 continue;
2260 }
2261 }
2262
2263 if (DebugDeoptimization && !deopt) {
2264 deopt = true; // One-time only print before deopt
2265 tty->print_cr("[BEFORE Deoptimization]");
2266 trace_frames();
2267 trace_stack();
2268 }
2269 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2270 }
2271 }
2272
2273 if (DebugDeoptimization && deopt) {
2274 tty->print_cr("[AFTER Deoptimization]");
2275 trace_frames();
2276 }
2277 }
2278
2279
2280 // Make zombies
2281 void JavaThread::make_zombies() {
2282 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2283 if (fst.current()->can_be_deoptimized()) {
2284 // it is a Java nmethod
2285 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2286 nm->make_not_entrant();
2287 }
2288 }
2289 }
2290 #endif // PRODUCT
2291
2292
2293 void JavaThread::deoptimized_wrt_marked_nmethods() {
2294 if (!has_last_Java_frame()) return;
2295 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2296 StackFrameStream fst(this, UseBiasedLocking);
2297 for(; !fst.is_done(); fst.next()) {
2298 if (fst.current()->should_be_deoptimized()) {
2299 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2300 }
2301 }
2302 }
2303
2304
2305 // GC support
2306 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2307
2308 void JavaThread::gc_epilogue() {
2309 frames_do(frame_gc_epilogue);
2310 }
2311
2312
2313 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2314
2315 void JavaThread::gc_prologue() {
2316 frames_do(frame_gc_prologue);
2317 }
2318
2319
2320 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2321 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2322 // since there may be more than one thread using each ThreadProfiler.
2323
2324 // Traverse the GCHandles
2325 Thread::oops_do(f, cf);
2326
2327 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2328 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2329
2330 if (has_last_Java_frame()) {
2331
2332 // Traverse the privileged stack
2333 if (_privileged_stack_top != NULL) {
2334 _privileged_stack_top->oops_do(f);
2335 }
2336
2337 // traverse the registered growable array
2338 if (_array_for_gc != NULL) {
2339 for (int index = 0; index < _array_for_gc->length(); index++) {
2340 f->do_oop(_array_for_gc->adr_at(index));
2341 }
2342 }
2343
2344 // Traverse the monitor chunks
2345 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2346 chunk->oops_do(f);
2347 }
2348
2349 // Traverse the execution stack
2350 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2351 fst.current()->oops_do(f, cf, fst.register_map());
2352 }
2353 }
2354
2355 // callee_target is never live across a gc point so NULL it here should
2356 // it still contain a methdOop.
2357
2358 set_callee_target(NULL);
2359
2360 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2361 // If we have deferred set_locals there might be oops waiting to be
2362 // written
2363 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2364 if (list != NULL) {
2365 for (int i = 0; i < list->length(); i++) {
2366 list->at(i)->oops_do(f);
2367 }
2368 }
2369
2370 // Traverse instance variables at the end since the GC may be moving things
2371 // around using this function
2372 f->do_oop((oop*) &_threadObj);
2373 f->do_oop((oop*) &_vm_result);
2374 f->do_oop((oop*) &_vm_result_2);
2375 f->do_oop((oop*) &_exception_oop);
2376 f->do_oop((oop*) &_pending_async_exception);
2377
2378 if (jvmti_thread_state() != NULL) {
2379 jvmti_thread_state()->oops_do(f);
2380 }
2381 }
2382
2383 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2384 Thread::nmethods_do(cf); // (super method is a no-op)
2385
2386 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2387 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2388
2389 if (has_last_Java_frame()) {
2390 // Traverse the execution stack
2391 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2392 fst.current()->nmethods_do(cf);
2393 }
2394 }
2395 }
2396
2397 // Printing
2398 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2399 switch (_thread_state) {
2400 case _thread_uninitialized: return "_thread_uninitialized";
2401 case _thread_new: return "_thread_new";
2402 case _thread_new_trans: return "_thread_new_trans";
2403 case _thread_in_native: return "_thread_in_native";
2404 case _thread_in_native_trans: return "_thread_in_native_trans";
2405 case _thread_in_vm: return "_thread_in_vm";
2406 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2407 case _thread_in_Java: return "_thread_in_Java";
2408 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2409 case _thread_blocked: return "_thread_blocked";
2410 case _thread_blocked_trans: return "_thread_blocked_trans";
2411 default: return "unknown thread state";
2412 }
2413 }
2414
2415 #ifndef PRODUCT
2416 void JavaThread::print_thread_state_on(outputStream *st) const {
2417 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2418 };
2419 void JavaThread::print_thread_state() const {
2420 print_thread_state_on(tty);
2421 };
2422 #endif // PRODUCT
2423
2424 // Called by Threads::print() for VM_PrintThreads operation
2425 void JavaThread::print_on(outputStream *st) const {
2426 st->print("\"%s\" ", get_thread_name());
2427 oop thread_oop = threadObj();
2428 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2429 Thread::print_on(st);
2430 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2431 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2432 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2433 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2434 }
2435 #ifndef PRODUCT
2436 print_thread_state_on(st);
2437 _safepoint_state->print_on(st);
2438 #endif // PRODUCT
2439 }
2440
2441 // Called by fatal error handler. The difference between this and
2442 // JavaThread::print() is that we can't grab lock or allocate memory.
2443 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2444 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2445 oop thread_obj = threadObj();
2446 if (thread_obj != NULL) {
2447 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2448 }
2449 st->print(" [");
2450 st->print("%s", _get_thread_state_name(_thread_state));
2451 if (osthread()) {
2452 st->print(", id=%d", osthread()->thread_id());
2453 }
2454 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2455 _stack_base - _stack_size, _stack_base);
2456 st->print("]");
2457 return;
2458 }
2459
2460 // Verification
2461
2462 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2463
2464 void JavaThread::verify() {
2465 // Verify oops in the thread.
2466 oops_do(&VerifyOopClosure::verify_oop, NULL);
2467
2468 // Verify the stack frames.
2469 frames_do(frame_verify);
2470 }
2471
2472 // CR 6300358 (sub-CR 2137150)
2473 // Most callers of this method assume that it can't return NULL but a
2474 // thread may not have a name whilst it is in the process of attaching to
2475 // the VM - see CR 6412693, and there are places where a JavaThread can be
2476 // seen prior to having it's threadObj set (eg JNI attaching threads and
2477 // if vm exit occurs during initialization). These cases can all be accounted
2478 // for such that this method never returns NULL.
2479 const char* JavaThread::get_thread_name() const {
2480 #ifdef ASSERT
2481 // early safepoints can hit while current thread does not yet have TLS
2482 if (!SafepointSynchronize::is_at_safepoint()) {
2483 Thread *cur = Thread::current();
2484 if (!(cur->is_Java_thread() && cur == this)) {
2485 // Current JavaThreads are allowed to get their own name without
2486 // the Threads_lock.
2487 assert_locked_or_safepoint(Threads_lock);
2488 }
2489 }
2490 #endif // ASSERT
2491 return get_thread_name_string();
2492 }
2493
2494 // Returns a non-NULL representation of this thread's name, or a suitable
2495 // descriptive string if there is no set name
2496 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2497 const char* name_str;
2498 oop thread_obj = threadObj();
2499 if (thread_obj != NULL) {
2500 typeArrayOop name = java_lang_Thread::name(thread_obj);
2501 if (name != NULL) {
2502 if (buf == NULL) {
2503 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2504 }
2505 else {
2506 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2507 }
2508 }
2509 else if (is_attaching()) { // workaround for 6412693 - see 6404306
2510 name_str = "<no-name - thread is attaching>";
2511 }
2512 else {
2513 name_str = Thread::name();
2514 }
2515 }
2516 else {
2517 name_str = Thread::name();
2518 }
2519 assert(name_str != NULL, "unexpected NULL thread name");
2520 return name_str;
2521 }
2522
2523
2524 const char* JavaThread::get_threadgroup_name() const {
2525 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2526 oop thread_obj = threadObj();
2527 if (thread_obj != NULL) {
2528 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2529 if (thread_group != NULL) {
2530 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2531 // ThreadGroup.name can be null
2532 if (name != NULL) {
2533 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2534 return str;
2535 }
2536 }
2537 }
2538 return NULL;
2539 }
2540
2541 const char* JavaThread::get_parent_name() const {
2542 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2543 oop thread_obj = threadObj();
2544 if (thread_obj != NULL) {
2545 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2546 if (thread_group != NULL) {
2547 oop parent = java_lang_ThreadGroup::parent(thread_group);
2548 if (parent != NULL) {
2549 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2550 // ThreadGroup.name can be null
2551 if (name != NULL) {
2552 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2553 return str;
2554 }
2555 }
2556 }
2557 }
2558 return NULL;
2559 }
2560
2561 ThreadPriority JavaThread::java_priority() const {
2562 oop thr_oop = threadObj();
2563 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2564 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2565 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2566 return priority;
2567 }
2568
2569 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2570
2571 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2572 // Link Java Thread object <-> C++ Thread
2573
2574 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2575 // and put it into a new Handle. The Handle "thread_oop" can then
2576 // be used to pass the C++ thread object to other methods.
2577
2578 // Set the Java level thread object (jthread) field of the
2579 // new thread (a JavaThread *) to C++ thread object using the
2580 // "thread_oop" handle.
2581
2582 // Set the thread field (a JavaThread *) of the
2583 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2584
2585 Handle thread_oop(Thread::current(),
2586 JNIHandles::resolve_non_null(jni_thread));
2587 assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
2588 "must be initialized");
2589 set_threadObj(thread_oop());
2590 java_lang_Thread::set_thread(thread_oop(), this);
2591
2592 if (prio == NoPriority) {
2593 prio = java_lang_Thread::priority(thread_oop());
2594 assert(prio != NoPriority, "A valid priority should be present");
2595 }
2596
2597 // Push the Java priority down to the native thread; needs Threads_lock
2598 Thread::set_priority(this, prio);
2599
2600 // Add the new thread to the Threads list and set it in motion.
2601 // We must have threads lock in order to call Threads::add.
2602 // It is crucial that we do not block before the thread is
2603 // added to the Threads list for if a GC happens, then the java_thread oop
2604 // will not be visited by GC.
2605 Threads::add(this);
2606 }
2607
2608 oop JavaThread::current_park_blocker() {
2609 // Support for JSR-166 locks
2610 oop thread_oop = threadObj();
2611 if (thread_oop != NULL &&
2612 JDK_Version::current().supports_thread_park_blocker()) {
2613 return java_lang_Thread::park_blocker(thread_oop);
2614 }
2615 return NULL;
2616 }
2617
2618
2619 void JavaThread::print_stack_on(outputStream* st) {
2620 if (!has_last_Java_frame()) return;
2621 ResourceMark rm;
2622 HandleMark hm;
2623
2624 RegisterMap reg_map(this);
2625 vframe* start_vf = last_java_vframe(®_map);
2626 int count = 0;
2627 for (vframe* f = start_vf; f; f = f->sender() ) {
2628 if (f->is_java_frame()) {
2629 javaVFrame* jvf = javaVFrame::cast(f);
2630 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2631
2632 // Print out lock information
2633 if (JavaMonitorsInStackTrace) {
2634 jvf->print_lock_info_on(st, count);
2635 }
2636 } else {
2637 // Ignore non-Java frames
2638 }
2639
2640 // Bail-out case for too deep stacks
2641 count++;
2642 if (MaxJavaStackTraceDepth == count) return;
2643 }
2644 }
2645
2646
2647 // JVMTI PopFrame support
2648 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2649 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2650 if (in_bytes(size_in_bytes) != 0) {
2651 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes));
2652 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2653 Copy::conjoint_bytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2654 }
2655 }
2656
2657 void* JavaThread::popframe_preserved_args() {
2658 return _popframe_preserved_args;
2659 }
2660
2661 ByteSize JavaThread::popframe_preserved_args_size() {
2662 return in_ByteSize(_popframe_preserved_args_size);
2663 }
2664
2665 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2666 int sz = in_bytes(popframe_preserved_args_size());
2667 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2668 return in_WordSize(sz / wordSize);
2669 }
2670
2671 void JavaThread::popframe_free_preserved_args() {
2672 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2673 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
2674 _popframe_preserved_args = NULL;
2675 _popframe_preserved_args_size = 0;
2676 }
2677
2678 #ifndef PRODUCT
2679
2680 void JavaThread::trace_frames() {
2681 tty->print_cr("[Describe stack]");
2682 int frame_no = 1;
2683 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2684 tty->print(" %d. ", frame_no++);
2685 fst.current()->print_value_on(tty,this);
2686 tty->cr();
2687 }
2688 }
2689
2690
2691 void JavaThread::trace_stack_from(vframe* start_vf) {
2692 ResourceMark rm;
2693 int vframe_no = 1;
2694 for (vframe* f = start_vf; f; f = f->sender() ) {
2695 if (f->is_java_frame()) {
2696 javaVFrame::cast(f)->print_activation(vframe_no++);
2697 } else {
2698 f->print();
2699 }
2700 if (vframe_no > StackPrintLimit) {
2701 tty->print_cr("...<more frames>...");
2702 return;
2703 }
2704 }
2705 }
2706
2707
2708 void JavaThread::trace_stack() {
2709 if (!has_last_Java_frame()) return;
2710 ResourceMark rm;
2711 HandleMark hm;
2712 RegisterMap reg_map(this);
2713 trace_stack_from(last_java_vframe(®_map));
2714 }
2715
2716
2717 #endif // PRODUCT
2718
2719
2720 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2721 assert(reg_map != NULL, "a map must be given");
2722 frame f = last_frame();
2723 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
2724 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2725 }
2726 return NULL;
2727 }
2728
2729
2730 klassOop JavaThread::security_get_caller_class(int depth) {
2731 vframeStream vfst(this);
2732 vfst.security_get_caller_frame(depth);
2733 if (!vfst.at_end()) {
2734 return vfst.method()->method_holder();
2735 }
2736 return NULL;
2737 }
2738
2739 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
2740 assert(thread->is_Compiler_thread(), "must be compiler thread");
2741 CompileBroker::compiler_thread_loop();
2742 }
2743
2744 // Create a CompilerThread
2745 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
2746 : JavaThread(&compiler_thread_entry) {
2747 _env = NULL;
2748 _log = NULL;
2749 _task = NULL;
2750 _queue = queue;
2751 _counters = counters;
2752
2753 #ifndef PRODUCT
2754 _ideal_graph_printer = NULL;
2755 #endif
2756 }
2757
2758
2759 // ======= Threads ========
2760
2761 // The Threads class links together all active threads, and provides
2762 // operations over all threads. It is protected by its own Mutex
2763 // lock, which is also used in other contexts to protect thread
2764 // operations from having the thread being operated on from exiting
2765 // and going away unexpectedly (e.g., safepoint synchronization)
2766
2767 JavaThread* Threads::_thread_list = NULL;
2768 int Threads::_number_of_threads = 0;
2769 int Threads::_number_of_non_daemon_threads = 0;
2770 int Threads::_return_code = 0;
2771 size_t JavaThread::_stack_size_at_create = 0;
2772
2773 // All JavaThreads
2774 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
2775
2776 void os_stream();
2777
2778 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
2779 void Threads::threads_do(ThreadClosure* tc) {
2780 assert_locked_or_safepoint(Threads_lock);
2781 // ALL_JAVA_THREADS iterates through all JavaThreads
2782 ALL_JAVA_THREADS(p) {
2783 tc->do_thread(p);
2784 }
2785 // Someday we could have a table or list of all non-JavaThreads.
2786 // For now, just manually iterate through them.
2787 tc->do_thread(VMThread::vm_thread());
2788 Universe::heap()->gc_threads_do(tc);
2789 WatcherThread *wt = WatcherThread::watcher_thread();
2790 // Strictly speaking, the following NULL check isn't sufficient to make sure
2791 // the data for WatcherThread is still valid upon being examined. However,
2792 // considering that WatchThread terminates when the VM is on the way to
2793 // exit at safepoint, the chance of the above is extremely small. The right
2794 // way to prevent termination of WatcherThread would be to acquire
2795 // Terminator_lock, but we can't do that without violating the lock rank
2796 // checking in some cases.
2797 if (wt != NULL)
2798 tc->do_thread(wt);
2799
2800 // If CompilerThreads ever become non-JavaThreads, add them here
2801 }
2802
2803 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
2804
2805 extern void JDK_Version_init();
2806
2807 // Check version
2808 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
2809
2810 // Initialize the output stream module
2811 ostream_init();
2812
2813 // Process java launcher properties.
2814 Arguments::process_sun_java_launcher_properties(args);
2815
2816 // Initialize the os module before using TLS
2817 os::init();
2818
2819 // Initialize system properties.
2820 Arguments::init_system_properties();
2821
2822 // So that JDK version can be used as a discrimintor when parsing arguments
2823 JDK_Version_init();
2824
2825 // Parse arguments
2826 jint parse_result = Arguments::parse(args);
2827 if (parse_result != JNI_OK) return parse_result;
2828
2829 if (PauseAtStartup) {
2830 os::pause();
2831 }
2832
2833 HS_DTRACE_PROBE(hotspot, vm__init__begin);
2834
2835 // Record VM creation timing statistics
2836 TraceVmCreationTime create_vm_timer;
2837 create_vm_timer.start();
2838
2839 // Timing (must come after argument parsing)
2840 TraceTime timer("Create VM", TraceStartupTime);
2841
2842 // Initialize the os module after parsing the args
2843 jint os_init_2_result = os::init_2();
2844 if (os_init_2_result != JNI_OK) return os_init_2_result;
2845
2846 // Initialize output stream logging
2847 ostream_init_log();
2848
2849 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
2850 // Must be before create_vm_init_agents()
2851 if (Arguments::init_libraries_at_startup()) {
2852 convert_vm_init_libraries_to_agents();
2853 }
2854
2855 // Launch -agentlib/-agentpath and converted -Xrun agents
2856 if (Arguments::init_agents_at_startup()) {
2857 create_vm_init_agents();
2858 }
2859
2860 // Initialize Threads state
2861 _thread_list = NULL;
2862 _number_of_threads = 0;
2863 _number_of_non_daemon_threads = 0;
2864
2865 // Initialize TLS
2866 ThreadLocalStorage::init();
2867
2868 // Initialize global data structures and create system classes in heap
2869 vm_init_globals();
2870
2871 // Attach the main thread to this os thread
2872 JavaThread* main_thread = new JavaThread();
2873 main_thread->set_thread_state(_thread_in_vm);
2874 // must do this before set_active_handles and initialize_thread_local_storage
2875 // Note: on solaris initialize_thread_local_storage() will (indirectly)
2876 // change the stack size recorded here to one based on the java thread
2877 // stacksize. This adjusted size is what is used to figure the placement
2878 // of the guard pages.
2879 main_thread->record_stack_base_and_size();
2880 main_thread->initialize_thread_local_storage();
2881
2882 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
2883
2884 if (!main_thread->set_as_starting_thread()) {
2885 vm_shutdown_during_initialization(
2886 "Failed necessary internal allocation. Out of swap space");
2887 delete main_thread;
2888 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2889 return JNI_ENOMEM;
2890 }
2891
2892 // Enable guard page *after* os::create_main_thread(), otherwise it would
2893 // crash Linux VM, see notes in os_linux.cpp.
2894 main_thread->create_stack_guard_pages();
2895
2896 // Initialize Java-Leve synchronization subsystem
2897 ObjectSynchronizer::Initialize() ;
2898
2899 // Initialize global modules
2900 jint status = init_globals();
2901 if (status != JNI_OK) {
2902 delete main_thread;
2903 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2904 return status;
2905 }
2906
2907 HandleMark hm;
2908
2909 { MutexLocker mu(Threads_lock);
2910 Threads::add(main_thread);
2911 }
2912
2913 // Any JVMTI raw monitors entered in onload will transition into
2914 // real raw monitor. VM is setup enough here for raw monitor enter.
2915 JvmtiExport::transition_pending_onload_raw_monitors();
2916
2917 if (VerifyBeforeGC &&
2918 Universe::heap()->total_collections() >= VerifyGCStartAt) {
2919 Universe::heap()->prepare_for_verify();
2920 Universe::verify(); // make sure we're starting with a clean slate
2921 }
2922
2923 // Create the VMThread
2924 { TraceTime timer("Start VMThread", TraceStartupTime);
2925 VMThread::create();
2926 Thread* vmthread = VMThread::vm_thread();
2927
2928 if (!os::create_thread(vmthread, os::vm_thread))
2929 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
2930
2931 // Wait for the VM thread to become ready, and VMThread::run to initialize
2932 // Monitors can have spurious returns, must always check another state flag
2933 {
2934 MutexLocker ml(Notify_lock);
2935 os::start_thread(vmthread);
2936 while (vmthread->active_handles() == NULL) {
2937 Notify_lock->wait();
2938 }
2939 }
2940 }
2941
2942 assert (Universe::is_fully_initialized(), "not initialized");
2943 EXCEPTION_MARK;
2944
2945 // At this point, the Universe is initialized, but we have not executed
2946 // any byte code. Now is a good time (the only time) to dump out the
2947 // internal state of the JVM for sharing.
2948
2949 if (DumpSharedSpaces) {
2950 Universe::heap()->preload_and_dump(CHECK_0);
2951 ShouldNotReachHere();
2952 }
2953
2954 // Always call even when there are not JVMTI environments yet, since environments
2955 // may be attached late and JVMTI must track phases of VM execution
2956 JvmtiExport::enter_start_phase();
2957
2958 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
2959 JvmtiExport::post_vm_start();
2960
2961 {
2962 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
2963
2964 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
2965 create_vm_init_libraries();
2966 }
2967
2968 if (InitializeJavaLangString) {
2969 initialize_class(vmSymbolHandles::java_lang_String(), CHECK_0);
2970 } else {
2971 warning("java.lang.String not initialized");
2972 }
2973
2974 if (AggressiveOpts) {
2975 {
2976 // Forcibly initialize java/util/HashMap and mutate the private
2977 // static final "frontCacheEnabled" field before we start creating instances
2978 #ifdef ASSERT
2979 klassOop tmp_k = SystemDictionary::find(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0);
2980 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
2981 #endif
2982 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0);
2983 KlassHandle k = KlassHandle(THREAD, k_o);
2984 guarantee(k.not_null(), "Must find java/util/HashMap");
2985 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
2986 ik->initialize(CHECK_0);
2987 fieldDescriptor fd;
2988 // Possible we might not find this field; if so, don't break
2989 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
2990 k()->bool_field_put(fd.offset(), true);
2991 }
2992 }
2993
2994 if (UseStringCache) {
2995 // Forcibly initialize java/lang/StringValue and mutate the private
2996 // static final "stringCacheEnabled" field before we start creating instances
2997 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
2998 // Possible that StringValue isn't present: if so, silently don't break
2999 if (k_o != NULL) {
3000 KlassHandle k = KlassHandle(THREAD, k_o);
3001 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3002 ik->initialize(CHECK_0);
3003 fieldDescriptor fd;
3004 // Possible we might not find this field: if so, silently don't break
3005 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3006 k()->bool_field_put(fd.offset(), true);
3007 }
3008 }
3009 }
3010 }
3011
3012 // Initialize java_lang.System (needed before creating the thread)
3013 if (InitializeJavaLangSystem) {
3014 initialize_class(vmSymbolHandles::java_lang_System(), CHECK_0);
3015 initialize_class(vmSymbolHandles::java_lang_ThreadGroup(), CHECK_0);
3016 Handle thread_group = create_initial_thread_group(CHECK_0);
3017 Universe::set_main_thread_group(thread_group());
3018 initialize_class(vmSymbolHandles::java_lang_Thread(), CHECK_0);
3019 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3020 main_thread->set_threadObj(thread_object);
3021 // Set thread status to running since main thread has
3022 // been started and running.
3023 java_lang_Thread::set_thread_status(thread_object,
3024 java_lang_Thread::RUNNABLE);
3025
3026 // The VM preresolve methods to these classes. Make sure that get initialized
3027 initialize_class(vmSymbolHandles::java_lang_reflect_Method(), CHECK_0);
3028 initialize_class(vmSymbolHandles::java_lang_ref_Finalizer(), CHECK_0);
3029 // The VM creates & returns objects of this class. Make sure it's initialized.
3030 initialize_class(vmSymbolHandles::java_lang_Class(), CHECK_0);
3031 call_initializeSystemClass(CHECK_0);
3032 } else {
3033 warning("java.lang.System not initialized");
3034 }
3035
3036 // an instance of OutOfMemory exception has been allocated earlier
3037 if (InitializeJavaLangExceptionsErrors) {
3038 initialize_class(vmSymbolHandles::java_lang_OutOfMemoryError(), CHECK_0);
3039 initialize_class(vmSymbolHandles::java_lang_NullPointerException(), CHECK_0);
3040 initialize_class(vmSymbolHandles::java_lang_ClassCastException(), CHECK_0);
3041 initialize_class(vmSymbolHandles::java_lang_ArrayStoreException(), CHECK_0);
3042 initialize_class(vmSymbolHandles::java_lang_ArithmeticException(), CHECK_0);
3043 initialize_class(vmSymbolHandles::java_lang_StackOverflowError(), CHECK_0);
3044 initialize_class(vmSymbolHandles::java_lang_IllegalMonitorStateException(), CHECK_0);
3045 } else {
3046 warning("java.lang.OutOfMemoryError has not been initialized");
3047 warning("java.lang.NullPointerException has not been initialized");
3048 warning("java.lang.ClassCastException has not been initialized");
3049 warning("java.lang.ArrayStoreException has not been initialized");
3050 warning("java.lang.ArithmeticException has not been initialized");
3051 warning("java.lang.StackOverflowError has not been initialized");
3052 }
3053 }
3054
3055 // See : bugid 4211085.
3056 // Background : the static initializer of java.lang.Compiler tries to read
3057 // property"java.compiler" and read & write property "java.vm.info".
3058 // When a security manager is installed through the command line
3059 // option "-Djava.security.manager", the above properties are not
3060 // readable and the static initializer for java.lang.Compiler fails
3061 // resulting in a NoClassDefFoundError. This can happen in any
3062 // user code which calls methods in java.lang.Compiler.
3063 // Hack : the hack is to pre-load and initialize this class, so that only
3064 // system domains are on the stack when the properties are read.
3065 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3066 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3067 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3068 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3069 // Once that is done, we should remove this hack.
3070 initialize_class(vmSymbolHandles::java_lang_Compiler(), CHECK_0);
3071
3072 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3073 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3074 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3075 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3076 // This should also be taken out as soon as 4211383 gets fixed.
3077 reset_vm_info_property(CHECK_0);
3078
3079 quicken_jni_functions();
3080
3081 // Set flag that basic initialization has completed. Used by exceptions and various
3082 // debug stuff, that does not work until all basic classes have been initialized.
3083 set_init_completed();
3084
3085 HS_DTRACE_PROBE(hotspot, vm__init__end);
3086
3087 // record VM initialization completion time
3088 Management::record_vm_init_completed();
3089
3090 // Compute system loader. Note that this has to occur after set_init_completed, since
3091 // valid exceptions may be thrown in the process.
3092 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3093 // set_init_completed has just been called, causing exceptions not to be shortcut
3094 // anymore. We call vm_exit_during_initialization directly instead.
3095 SystemDictionary::compute_java_system_loader(THREAD);
3096 if (HAS_PENDING_EXCEPTION) {
3097 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3098 }
3099
3100 #ifndef SERIALGC
3101 // Support for ConcurrentMarkSweep. This should be cleaned up
3102 // and better encapsulated. The ugly nested if test would go away
3103 // once things are properly refactored. XXX YSR
3104 if (UseConcMarkSweepGC || UseG1GC) {
3105 if (UseConcMarkSweepGC) {
3106 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3107 } else {
3108 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3109 }
3110 if (HAS_PENDING_EXCEPTION) {
3111 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3112 }
3113 }
3114 #endif // SERIALGC
3115
3116 // Always call even when there are not JVMTI environments yet, since environments
3117 // may be attached late and JVMTI must track phases of VM execution
3118 JvmtiExport::enter_live_phase();
3119
3120 // Signal Dispatcher needs to be started before VMInit event is posted
3121 os::signal_init();
3122
3123 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3124 if (!DisableAttachMechanism) {
3125 if (StartAttachListener || AttachListener::init_at_startup()) {
3126 AttachListener::init();
3127 }
3128 }
3129
3130 // Launch -Xrun agents
3131 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3132 // back-end can launch with -Xdebug -Xrunjdwp.
3133 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3134 create_vm_init_libraries();
3135 }
3136
3137 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3138 JvmtiExport::post_vm_initialized();
3139
3140 Chunk::start_chunk_pool_cleaner_task();
3141
3142 // initialize compiler(s)
3143 CompileBroker::compilation_init();
3144
3145 Management::initialize(THREAD);
3146 if (HAS_PENDING_EXCEPTION) {
3147 // management agent fails to start possibly due to
3148 // configuration problem and is responsible for printing
3149 // stack trace if appropriate. Simply exit VM.
3150 vm_exit(1);
3151 }
3152
3153 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3154 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3155 if (MemProfiling) MemProfiler::engage();
3156 StatSampler::engage();
3157 if (CheckJNICalls) JniPeriodicChecker::engage();
3158
3159 BiasedLocking::init();
3160
3161
3162 // Start up the WatcherThread if there are any periodic tasks
3163 // NOTE: All PeriodicTasks should be registered by now. If they
3164 // aren't, late joiners might appear to start slowly (we might
3165 // take a while to process their first tick).
3166 if (PeriodicTask::num_tasks() > 0) {
3167 WatcherThread::start();
3168 }
3169
3170 create_vm_timer.end();
3171 return JNI_OK;
3172 }
3173
3174 // type for the Agent_OnLoad and JVM_OnLoad entry points
3175 extern "C" {
3176 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3177 }
3178 // Find a command line agent library and return its entry point for
3179 // -agentlib: -agentpath: -Xrun
3180 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3181 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3182 OnLoadEntry_t on_load_entry = NULL;
3183 void *library = agent->os_lib(); // check if we have looked it up before
3184
3185 if (library == NULL) {
3186 char buffer[JVM_MAXPATHLEN];
3187 char ebuf[1024];
3188 const char *name = agent->name();
3189
3190 if (agent->is_absolute_path()) {
3191 library = hpi::dll_load(name, ebuf, sizeof ebuf);
3192 if (library == NULL) {
3193 // If we can't find the agent, exit.
3194 vm_exit_during_initialization("Could not find agent library in absolute path", name);
3195 }
3196 } else {
3197 // Try to load the agent from the standard dll directory
3198 hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
3199 library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3200 #ifdef KERNEL
3201 // Download instrument dll
3202 if (library == NULL && strcmp(name, "instrument") == 0) {
3203 char *props = Arguments::get_kernel_properties();
3204 char *home = Arguments::get_java_home();
3205 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false"
3206 " sun.jkernel.DownloadManager -download client_jvm";
3207 int length = strlen(props) + strlen(home) + strlen(fmt) + 1;
3208 char *cmd = AllocateHeap(length);
3209 jio_snprintf(cmd, length, fmt, home, props);
3210 int status = os::fork_and_exec(cmd);
3211 FreeHeap(props);
3212 FreeHeap(cmd);
3213 if (status == -1) {
3214 warning(cmd);
3215 vm_exit_during_initialization("fork_and_exec failed: %s",
3216 strerror(errno));
3217 }
3218 // when this comes back the instrument.dll should be where it belongs.
3219 library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3220 }
3221 #endif // KERNEL
3222 if (library == NULL) { // Try the local directory
3223 char ns[1] = {0};
3224 hpi::dll_build_name(buffer, sizeof(buffer), ns, name);
3225 library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3226 if (library == NULL) {
3227 // If we can't find the agent, exit.
3228 vm_exit_during_initialization("Could not find agent library on the library path or in the local directory", name);
3229 }
3230 }
3231 }
3232 agent->set_os_lib(library);
3233 }
3234
3235 // Find the OnLoad function.
3236 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3237 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, hpi::dll_lookup(library, on_load_symbols[symbol_index]));
3238 if (on_load_entry != NULL) break;
3239 }
3240 return on_load_entry;
3241 }
3242
3243 // Find the JVM_OnLoad entry point
3244 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3245 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3246 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3247 }
3248
3249 // Find the Agent_OnLoad entry point
3250 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3251 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3252 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3253 }
3254
3255 // For backwards compatibility with -Xrun
3256 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3257 // treated like -agentpath:
3258 // Must be called before agent libraries are created
3259 void Threads::convert_vm_init_libraries_to_agents() {
3260 AgentLibrary* agent;
3261 AgentLibrary* next;
3262
3263 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3264 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3265 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3266
3267 // If there is an JVM_OnLoad function it will get called later,
3268 // otherwise see if there is an Agent_OnLoad
3269 if (on_load_entry == NULL) {
3270 on_load_entry = lookup_agent_on_load(agent);
3271 if (on_load_entry != NULL) {
3272 // switch it to the agent list -- so that Agent_OnLoad will be called,
3273 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3274 Arguments::convert_library_to_agent(agent);
3275 } else {
3276 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3277 }
3278 }
3279 }
3280 }
3281
3282 // Create agents for -agentlib: -agentpath: and converted -Xrun
3283 // Invokes Agent_OnLoad
3284 // Called very early -- before JavaThreads exist
3285 void Threads::create_vm_init_agents() {
3286 extern struct JavaVM_ main_vm;
3287 AgentLibrary* agent;
3288
3289 JvmtiExport::enter_onload_phase();
3290 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3291 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3292
3293 if (on_load_entry != NULL) {
3294 // Invoke the Agent_OnLoad function
3295 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3296 if (err != JNI_OK) {
3297 vm_exit_during_initialization("agent library failed to init", agent->name());
3298 }
3299 } else {
3300 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3301 }
3302 }
3303 JvmtiExport::enter_primordial_phase();
3304 }
3305
3306 extern "C" {
3307 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3308 }
3309
3310 void Threads::shutdown_vm_agents() {
3311 // Send any Agent_OnUnload notifications
3312 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3313 extern struct JavaVM_ main_vm;
3314 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3315
3316 // Find the Agent_OnUnload function.
3317 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3318 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3319 hpi::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3320
3321 // Invoke the Agent_OnUnload function
3322 if (unload_entry != NULL) {
3323 JavaThread* thread = JavaThread::current();
3324 ThreadToNativeFromVM ttn(thread);
3325 HandleMark hm(thread);
3326 (*unload_entry)(&main_vm);
3327 break;
3328 }
3329 }
3330 }
3331 }
3332
3333 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3334 // Invokes JVM_OnLoad
3335 void Threads::create_vm_init_libraries() {
3336 extern struct JavaVM_ main_vm;
3337 AgentLibrary* agent;
3338
3339 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3340 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3341
3342 if (on_load_entry != NULL) {
3343 // Invoke the JVM_OnLoad function
3344 JavaThread* thread = JavaThread::current();
3345 ThreadToNativeFromVM ttn(thread);
3346 HandleMark hm(thread);
3347 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3348 if (err != JNI_OK) {
3349 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3350 }
3351 } else {
3352 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3353 }
3354 }
3355 }
3356
3357 // Last thread running calls java.lang.Shutdown.shutdown()
3358 void JavaThread::invoke_shutdown_hooks() {
3359 HandleMark hm(this);
3360
3361 // We could get here with a pending exception, if so clear it now.
3362 if (this->has_pending_exception()) {
3363 this->clear_pending_exception();
3364 }
3365
3366 EXCEPTION_MARK;
3367 klassOop k =
3368 SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_Shutdown(),
3369 THREAD);
3370 if (k != NULL) {
3371 // SystemDictionary::resolve_or_null will return null if there was
3372 // an exception. If we cannot load the Shutdown class, just don't
3373 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3374 // and finalizers (if runFinalizersOnExit is set) won't be run.
3375 // Note that if a shutdown hook was registered or runFinalizersOnExit
3376 // was called, the Shutdown class would have already been loaded
3377 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3378 instanceKlassHandle shutdown_klass (THREAD, k);
3379 JavaValue result(T_VOID);
3380 JavaCalls::call_static(&result,
3381 shutdown_klass,
3382 vmSymbolHandles::shutdown_method_name(),
3383 vmSymbolHandles::void_method_signature(),
3384 THREAD);
3385 }
3386 CLEAR_PENDING_EXCEPTION;
3387 }
3388
3389 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3390 // the program falls off the end of main(). Another VM exit path is through
3391 // vm_exit() when the program calls System.exit() to return a value or when
3392 // there is a serious error in VM. The two shutdown paths are not exactly
3393 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3394 // and VM_Exit op at VM level.
3395 //
3396 // Shutdown sequence:
3397 // + Wait until we are the last non-daemon thread to execute
3398 // <-- every thing is still working at this moment -->
3399 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3400 // shutdown hooks, run finalizers if finalization-on-exit
3401 // + Call before_exit(), prepare for VM exit
3402 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3403 // currently the only user of this mechanism is File.deleteOnExit())
3404 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3405 // post thread end and vm death events to JVMTI,
3406 // stop signal thread
3407 // + Call JavaThread::exit(), it will:
3408 // > release JNI handle blocks, remove stack guard pages
3409 // > remove this thread from Threads list
3410 // <-- no more Java code from this thread after this point -->
3411 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3412 // the compiler threads at safepoint
3413 // <-- do not use anything that could get blocked by Safepoint -->
3414 // + Disable tracing at JNI/JVM barriers
3415 // + Set _vm_exited flag for threads that are still running native code
3416 // + Delete this thread
3417 // + Call exit_globals()
3418 // > deletes tty
3419 // > deletes PerfMemory resources
3420 // + Return to caller
3421
3422 bool Threads::destroy_vm() {
3423 JavaThread* thread = JavaThread::current();
3424
3425 // Wait until we are the last non-daemon thread to execute
3426 { MutexLocker nu(Threads_lock);
3427 while (Threads::number_of_non_daemon_threads() > 1 )
3428 // This wait should make safepoint checks, wait without a timeout,
3429 // and wait as a suspend-equivalent condition.
3430 //
3431 // Note: If the FlatProfiler is running and this thread is waiting
3432 // for another non-daemon thread to finish, then the FlatProfiler
3433 // is waiting for the external suspend request on this thread to
3434 // complete. wait_for_ext_suspend_completion() will eventually
3435 // timeout, but that takes time. Making this wait a suspend-
3436 // equivalent condition solves that timeout problem.
3437 //
3438 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3439 Mutex::_as_suspend_equivalent_flag);
3440 }
3441
3442 // Hang forever on exit if we are reporting an error.
3443 if (ShowMessageBoxOnError && is_error_reported()) {
3444 os::infinite_sleep();
3445 }
3446
3447 if (JDK_Version::is_jdk12x_version()) {
3448 // We are the last thread running, so check if finalizers should be run.
3449 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3450 HandleMark rm(thread);
3451 Universe::run_finalizers_on_exit();
3452 } else {
3453 // run Java level shutdown hooks
3454 thread->invoke_shutdown_hooks();
3455 }
3456
3457 before_exit(thread);
3458
3459 thread->exit(true);
3460
3461 // Stop VM thread.
3462 {
3463 // 4945125 The vm thread comes to a safepoint during exit.
3464 // GC vm_operations can get caught at the safepoint, and the
3465 // heap is unparseable if they are caught. Grab the Heap_lock
3466 // to prevent this. The GC vm_operations will not be able to
3467 // queue until after the vm thread is dead.
3468 MutexLocker ml(Heap_lock);
3469
3470 VMThread::wait_for_vm_thread_exit();
3471 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3472 VMThread::destroy();
3473 }
3474
3475 // clean up ideal graph printers
3476 #if defined(COMPILER2) && !defined(PRODUCT)
3477 IdealGraphPrinter::clean_up();
3478 #endif
3479
3480 // Now, all Java threads are gone except daemon threads. Daemon threads
3481 // running Java code or in VM are stopped by the Safepoint. However,
3482 // daemon threads executing native code are still running. But they
3483 // will be stopped at native=>Java/VM barriers. Note that we can't
3484 // simply kill or suspend them, as it is inherently deadlock-prone.
3485
3486 #ifndef PRODUCT
3487 // disable function tracing at JNI/JVM barriers
3488 TraceHPI = false;
3489 TraceJNICalls = false;
3490 TraceJVMCalls = false;
3491 TraceRuntimeCalls = false;
3492 #endif
3493
3494 VM_Exit::set_vm_exited();
3495
3496 notify_vm_shutdown();
3497
3498 delete thread;
3499
3500 // exit_globals() will delete tty
3501 exit_globals();
3502
3503 return true;
3504 }
3505
3506
3507 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3508 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3509 return is_supported_jni_version(version);
3510 }
3511
3512
3513 jboolean Threads::is_supported_jni_version(jint version) {
3514 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3515 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3516 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3517 return JNI_FALSE;
3518 }
3519
3520
3521 void Threads::add(JavaThread* p, bool force_daemon) {
3522 // The threads lock must be owned at this point
3523 assert_locked_or_safepoint(Threads_lock);
3524 p->set_next(_thread_list);
3525 _thread_list = p;
3526 _number_of_threads++;
3527 oop threadObj = p->threadObj();
3528 bool daemon = true;
3529 // Bootstrapping problem: threadObj can be null for initial
3530 // JavaThread (or for threads attached via JNI)
3531 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3532 _number_of_non_daemon_threads++;
3533 daemon = false;
3534 }
3535
3536 ThreadService::add_thread(p, daemon);
3537
3538 // Possible GC point.
3539 Events::log("Thread added: " INTPTR_FORMAT, p);
3540 }
3541
3542 void Threads::remove(JavaThread* p) {
3543 // Extra scope needed for Thread_lock, so we can check
3544 // that we do not remove thread without safepoint code notice
3545 { MutexLocker ml(Threads_lock);
3546
3547 assert(includes(p), "p must be present");
3548
3549 JavaThread* current = _thread_list;
3550 JavaThread* prev = NULL;
3551
3552 while (current != p) {
3553 prev = current;
3554 current = current->next();
3555 }
3556
3557 if (prev) {
3558 prev->set_next(current->next());
3559 } else {
3560 _thread_list = p->next();
3561 }
3562 _number_of_threads--;
3563 oop threadObj = p->threadObj();
3564 bool daemon = true;
3565 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
3566 _number_of_non_daemon_threads--;
3567 daemon = false;
3568
3569 // Only one thread left, do a notify on the Threads_lock so a thread waiting
3570 // on destroy_vm will wake up.
3571 if (number_of_non_daemon_threads() == 1)
3572 Threads_lock->notify_all();
3573 }
3574 ThreadService::remove_thread(p, daemon);
3575
3576 // Make sure that safepoint code disregard this thread. This is needed since
3577 // the thread might mess around with locks after this point. This can cause it
3578 // to do callbacks into the safepoint code. However, the safepoint code is not aware
3579 // of this thread since it is removed from the queue.
3580 p->set_terminated_value();
3581 } // unlock Threads_lock
3582
3583 // Since Events::log uses a lock, we grab it outside the Threads_lock
3584 Events::log("Thread exited: " INTPTR_FORMAT, p);
3585 }
3586
3587 // Threads_lock must be held when this is called (or must be called during a safepoint)
3588 bool Threads::includes(JavaThread* p) {
3589 assert(Threads_lock->is_locked(), "sanity check");
3590 ALL_JAVA_THREADS(q) {
3591 if (q == p ) {
3592 return true;
3593 }
3594 }
3595 return false;
3596 }
3597
3598 // Operations on the Threads list for GC. These are not explicitly locked,
3599 // but the garbage collector must provide a safe context for them to run.
3600 // In particular, these things should never be called when the Threads_lock
3601 // is held by some other thread. (Note: the Safepoint abstraction also
3602 // uses the Threads_lock to gurantee this property. It also makes sure that
3603 // all threads gets blocked when exiting or starting).
3604
3605 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3606 ALL_JAVA_THREADS(p) {
3607 p->oops_do(f, cf);
3608 }
3609 VMThread::vm_thread()->oops_do(f, cf);
3610 }
3611
3612 void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) {
3613 // Introduce a mechanism allowing parallel threads to claim threads as
3614 // root groups. Overhead should be small enough to use all the time,
3615 // even in sequential code.
3616 SharedHeap* sh = SharedHeap::heap();
3617 bool is_par = (sh->n_par_threads() > 0);
3618 int cp = SharedHeap::heap()->strong_roots_parity();
3619 ALL_JAVA_THREADS(p) {
3620 if (p->claim_oops_do(is_par, cp)) {
3621 p->oops_do(f, cf);
3622 }
3623 }
3624 VMThread* vmt = VMThread::vm_thread();
3625 if (vmt->claim_oops_do(is_par, cp))
3626 vmt->oops_do(f, cf);
3627 }
3628
3629 #ifndef SERIALGC
3630 // Used by ParallelScavenge
3631 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
3632 ALL_JAVA_THREADS(p) {
3633 q->enqueue(new ThreadRootsTask(p));
3634 }
3635 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
3636 }
3637
3638 // Used by Parallel Old
3639 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
3640 ALL_JAVA_THREADS(p) {
3641 q->enqueue(new ThreadRootsMarkingTask(p));
3642 }
3643 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
3644 }
3645 #endif // SERIALGC
3646
3647 void Threads::nmethods_do(CodeBlobClosure* cf) {
3648 ALL_JAVA_THREADS(p) {
3649 p->nmethods_do(cf);
3650 }
3651 VMThread::vm_thread()->nmethods_do(cf);
3652 }
3653
3654 void Threads::gc_epilogue() {
3655 ALL_JAVA_THREADS(p) {
3656 p->gc_epilogue();
3657 }
3658 }
3659
3660 void Threads::gc_prologue() {
3661 ALL_JAVA_THREADS(p) {
3662 p->gc_prologue();
3663 }
3664 }
3665
3666 void Threads::deoptimized_wrt_marked_nmethods() {
3667 ALL_JAVA_THREADS(p) {
3668 p->deoptimized_wrt_marked_nmethods();
3669 }
3670 }
3671
3672
3673 // Get count Java threads that are waiting to enter the specified monitor.
3674 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
3675 address monitor, bool doLock) {
3676 assert(doLock || SafepointSynchronize::is_at_safepoint(),
3677 "must grab Threads_lock or be at safepoint");
3678 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3679
3680 int i = 0;
3681 {
3682 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3683 ALL_JAVA_THREADS(p) {
3684 if (p->is_Compiler_thread()) continue;
3685
3686 address pending = (address)p->current_pending_monitor();
3687 if (pending == monitor) { // found a match
3688 if (i < count) result->append(p); // save the first count matches
3689 i++;
3690 }
3691 }
3692 }
3693 return result;
3694 }
3695
3696
3697 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
3698 assert(doLock ||
3699 Threads_lock->owned_by_self() ||
3700 SafepointSynchronize::is_at_safepoint(),
3701 "must grab Threads_lock or be at safepoint");
3702
3703 // NULL owner means not locked so we can skip the search
3704 if (owner == NULL) return NULL;
3705
3706 {
3707 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3708 ALL_JAVA_THREADS(p) {
3709 // first, see if owner is the address of a Java thread
3710 if (owner == (address)p) return p;
3711 }
3712 }
3713 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
3714 if (UseHeavyMonitors) return NULL;
3715
3716 //
3717 // If we didn't find a matching Java thread and we didn't force use of
3718 // heavyweight monitors, then the owner is the stack address of the
3719 // Lock Word in the owning Java thread's stack.
3720 //
3721 JavaThread* the_owner = NULL;
3722 {
3723 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3724 ALL_JAVA_THREADS(q) {
3725 if (q->is_lock_owned(owner)) {
3726 the_owner = q;
3727 break;
3728 }
3729 }
3730 }
3731 assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
3732 return the_owner;
3733 }
3734
3735 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
3736 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
3737 char buf[32];
3738 st->print_cr(os::local_time_string(buf, sizeof(buf)));
3739
3740 st->print_cr("Full thread dump %s (%s %s):",
3741 Abstract_VM_Version::vm_name(),
3742 Abstract_VM_Version::vm_release(),
3743 Abstract_VM_Version::vm_info_string()
3744 );
3745 st->cr();
3746
3747 #ifndef SERIALGC
3748 // Dump concurrent locks
3749 ConcurrentLocksDump concurrent_locks;
3750 if (print_concurrent_locks) {
3751 concurrent_locks.dump_at_safepoint();
3752 }
3753 #endif // SERIALGC
3754
3755 ALL_JAVA_THREADS(p) {
3756 ResourceMark rm;
3757 p->print_on(st);
3758 if (print_stacks) {
3759 if (internal_format) {
3760 p->trace_stack();
3761 } else {
3762 p->print_stack_on(st);
3763 }
3764 }
3765 st->cr();
3766 #ifndef SERIALGC
3767 if (print_concurrent_locks) {
3768 concurrent_locks.print_locks_on(p, st);
3769 }
3770 #endif // SERIALGC
3771 }
3772
3773 VMThread::vm_thread()->print_on(st);
3774 st->cr();
3775 Universe::heap()->print_gc_threads_on(st);
3776 WatcherThread* wt = WatcherThread::watcher_thread();
3777 if (wt != NULL) wt->print_on(st);
3778 st->cr();
3779 CompileBroker::print_compiler_threads_on(st);
3780 st->flush();
3781 }
3782
3783 // Threads::print_on_error() is called by fatal error handler. It's possible
3784 // that VM is not at safepoint and/or current thread is inside signal handler.
3785 // Don't print stack trace, as the stack may not be walkable. Don't allocate
3786 // memory (even in resource area), it might deadlock the error handler.
3787 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
3788 bool found_current = false;
3789 st->print_cr("Java Threads: ( => current thread )");
3790 ALL_JAVA_THREADS(thread) {
3791 bool is_current = (current == thread);
3792 found_current = found_current || is_current;
3793
3794 st->print("%s", is_current ? "=>" : " ");
3795
3796 st->print(PTR_FORMAT, thread);
3797 st->print(" ");
3798 thread->print_on_error(st, buf, buflen);
3799 st->cr();
3800 }
3801 st->cr();
3802
3803 st->print_cr("Other Threads:");
3804 if (VMThread::vm_thread()) {
3805 bool is_current = (current == VMThread::vm_thread());
3806 found_current = found_current || is_current;
3807 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
3808
3809 st->print(PTR_FORMAT, VMThread::vm_thread());
3810 st->print(" ");
3811 VMThread::vm_thread()->print_on_error(st, buf, buflen);
3812 st->cr();
3813 }
3814 WatcherThread* wt = WatcherThread::watcher_thread();
3815 if (wt != NULL) {
3816 bool is_current = (current == wt);
3817 found_current = found_current || is_current;
3818 st->print("%s", is_current ? "=>" : " ");
3819
3820 st->print(PTR_FORMAT, wt);
3821 st->print(" ");
3822 wt->print_on_error(st, buf, buflen);
3823 st->cr();
3824 }
3825 if (!found_current) {
3826 st->cr();
3827 st->print("=>" PTR_FORMAT " (exited) ", current);
3828 current->print_on_error(st, buf, buflen);
3829 st->cr();
3830 }
3831 }
3832
3833
3834 // Lifecycle management for TSM ParkEvents.
3835 // ParkEvents are type-stable (TSM).
3836 // In our particular implementation they happen to be immortal.
3837 //
3838 // We manage concurrency on the FreeList with a CAS-based
3839 // detach-modify-reattach idiom that avoids the ABA problems
3840 // that would otherwise be present in a simple CAS-based
3841 // push-pop implementation. (push-one and pop-all)
3842 //
3843 // Caveat: Allocate() and Release() may be called from threads
3844 // other than the thread associated with the Event!
3845 // If we need to call Allocate() when running as the thread in
3846 // question then look for the PD calls to initialize native TLS.
3847 // Native TLS (Win32/Linux/Solaris) can only be initialized or
3848 // accessed by the associated thread.
3849 // See also pd_initialize().
3850 //
3851 // Note that we could defer associating a ParkEvent with a thread
3852 // until the 1st time the thread calls park(). unpark() calls to
3853 // an unprovisioned thread would be ignored. The first park() call
3854 // for a thread would allocate and associate a ParkEvent and return
3855 // immediately.
3856
3857 volatile int ParkEvent::ListLock = 0 ;
3858 ParkEvent * volatile ParkEvent::FreeList = NULL ;
3859
3860 ParkEvent * ParkEvent::Allocate (Thread * t) {
3861 // In rare cases -- JVM_RawMonitor* operations -- we can find t == null.
3862 ParkEvent * ev ;
3863
3864 // Start by trying to recycle an existing but unassociated
3865 // ParkEvent from the global free list.
3866 for (;;) {
3867 ev = FreeList ;
3868 if (ev == NULL) break ;
3869 // 1: Detach - sequester or privatize the list
3870 // Tantamount to ev = Swap (&FreeList, NULL)
3871 if (Atomic::cmpxchg_ptr (NULL, &FreeList, ev) != ev) {
3872 continue ;
3873 }
3874
3875 // We've detached the list. The list in-hand is now
3876 // local to this thread. This thread can operate on the
3877 // list without risk of interference from other threads.
3878 // 2: Extract -- pop the 1st element from the list.
3879 ParkEvent * List = ev->FreeNext ;
3880 if (List == NULL) break ;
3881 for (;;) {
3882 // 3: Try to reattach the residual list
3883 guarantee (List != NULL, "invariant") ;
3884 ParkEvent * Arv = (ParkEvent *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ;
3885 if (Arv == NULL) break ;
3886
3887 // New nodes arrived. Try to detach the recent arrivals.
3888 if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) {
3889 continue ;
3890 }
3891 guarantee (Arv != NULL, "invariant") ;
3892 // 4: Merge Arv into List
3893 ParkEvent * Tail = List ;
3894 while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ;
3895 Tail->FreeNext = Arv ;
3896 }
3897 break ;
3898 }
3899
3900 if (ev != NULL) {
3901 guarantee (ev->AssociatedWith == NULL, "invariant") ;
3902 } else {
3903 // Do this the hard way -- materialize a new ParkEvent.
3904 // In rare cases an allocating thread might detach a long list --
3905 // installing null into FreeList -- and then stall or be obstructed.
3906 // A 2nd thread calling Allocate() would see FreeList == null.
3907 // The list held privately by the 1st thread is unavailable to the 2nd thread.
3908 // In that case the 2nd thread would have to materialize a new ParkEvent,
3909 // even though free ParkEvents existed in the system. In this case we end up
3910 // with more ParkEvents in circulation than we need, but the race is
3911 // rare and the outcome is benign. Ideally, the # of extant ParkEvents
3912 // is equal to the maximum # of threads that existed at any one time.
3913 // Because of the race mentioned above, segments of the freelist
3914 // can be transiently inaccessible. At worst we may end up with the
3915 // # of ParkEvents in circulation slightly above the ideal.
3916 // Note that if we didn't have the TSM/immortal constraint, then
3917 // when reattaching, above, we could trim the list.
3918 ev = new ParkEvent () ;
3919 guarantee ((intptr_t(ev) & 0xFF) == 0, "invariant") ;
3920 }
3921 ev->reset() ; // courtesy to caller
3922 ev->AssociatedWith = t ; // Associate ev with t
3923 ev->FreeNext = NULL ;
3924 return ev ;
3925 }
3926
3927 void ParkEvent::Release (ParkEvent * ev) {
3928 if (ev == NULL) return ;
3929 guarantee (ev->FreeNext == NULL , "invariant") ;
3930 ev->AssociatedWith = NULL ;
3931 for (;;) {
3932 // Push ev onto FreeList
3933 // The mechanism is "half" lock-free.
3934 ParkEvent * List = FreeList ;
3935 ev->FreeNext = List ;
3936 if (Atomic::cmpxchg_ptr (ev, &FreeList, List) == List) break ;
3937 }
3938 }
3939
3940 // Override operator new and delete so we can ensure that the
3941 // least significant byte of ParkEvent addresses is 0.
3942 // Beware that excessive address alignment is undesirable
3943 // as it can result in D$ index usage imbalance as
3944 // well as bank access imbalance on Niagara-like platforms,
3945 // although Niagara's hash function should help.
3946
3947 void * ParkEvent::operator new (size_t sz) {
3948 return (void *) ((intptr_t (CHeapObj::operator new (sz + 256)) + 256) & -256) ;
3949 }
3950
3951 void ParkEvent::operator delete (void * a) {
3952 // ParkEvents are type-stable and immortal ...
3953 ShouldNotReachHere();
3954 }
3955
3956
3957 // 6399321 As a temporary measure we copied & modified the ParkEvent::
3958 // allocate() and release() code for use by Parkers. The Parker:: forms
3959 // will eventually be removed as we consolide and shift over to ParkEvents
3960 // for both builtin synchronization and JSR166 operations.
3961
3962 volatile int Parker::ListLock = 0 ;
3963 Parker * volatile Parker::FreeList = NULL ;
3964
3965 Parker * Parker::Allocate (JavaThread * t) {
3966 guarantee (t != NULL, "invariant") ;
3967 Parker * p ;
3968
3969 // Start by trying to recycle an existing but unassociated
3970 // Parker from the global free list.
3971 for (;;) {
3972 p = FreeList ;
3973 if (p == NULL) break ;
3974 // 1: Detach
3975 // Tantamount to p = Swap (&FreeList, NULL)
3976 if (Atomic::cmpxchg_ptr (NULL, &FreeList, p) != p) {
3977 continue ;
3978 }
3979
3980 // We've detached the list. The list in-hand is now
3981 // local to this thread. This thread can operate on the
3982 // list without risk of interference from other threads.
3983 // 2: Extract -- pop the 1st element from the list.
3984 Parker * List = p->FreeNext ;
3985 if (List == NULL) break ;
3986 for (;;) {
3987 // 3: Try to reattach the residual list
3988 guarantee (List != NULL, "invariant") ;
3989 Parker * Arv = (Parker *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ;
3990 if (Arv == NULL) break ;
3991
3992 // New nodes arrived. Try to detach the recent arrivals.
3993 if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) {
3994 continue ;
3995 }
3996 guarantee (Arv != NULL, "invariant") ;
3997 // 4: Merge Arv into List
3998 Parker * Tail = List ;
3999 while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ;
4000 Tail->FreeNext = Arv ;
4001 }
4002 break ;
4003 }
4004
4005 if (p != NULL) {
4006 guarantee (p->AssociatedWith == NULL, "invariant") ;
4007 } else {
4008 // Do this the hard way -- materialize a new Parker..
4009 // In rare cases an allocating thread might detach
4010 // a long list -- installing null into FreeList --and
4011 // then stall. Another thread calling Allocate() would see
4012 // FreeList == null and then invoke the ctor. In this case we
4013 // end up with more Parkers in circulation than we need, but
4014 // the race is rare and the outcome is benign.
4015 // Ideally, the # of extant Parkers is equal to the
4016 // maximum # of threads that existed at any one time.
4017 // Because of the race mentioned above, segments of the
4018 // freelist can be transiently inaccessible. At worst
4019 // we may end up with the # of Parkers in circulation
4020 // slightly above the ideal.
4021 p = new Parker() ;
4022 }
4023 p->AssociatedWith = t ; // Associate p with t
4024 p->FreeNext = NULL ;
4025 return p ;
4026 }
4027
4028
4029 void Parker::Release (Parker * p) {
4030 if (p == NULL) return ;
4031 guarantee (p->AssociatedWith != NULL, "invariant") ;
4032 guarantee (p->FreeNext == NULL , "invariant") ;
4033 p->AssociatedWith = NULL ;
4034 for (;;) {
4035 // Push p onto FreeList
4036 Parker * List = FreeList ;
4037 p->FreeNext = List ;
4038 if (Atomic::cmpxchg_ptr (p, &FreeList, List) == List) break ;
4039 }
4040 }
4041
4042 void Threads::verify() {
4043 ALL_JAVA_THREADS(p) {
4044 p->verify();
4045 }
4046 VMThread* thread = VMThread::vm_thread();
4047 if (thread != NULL) thread->verify();
4048 }