Thu, 02 Apr 2009 18:17:03 -0400
Merge
1 /*
2 * Copyright 1997-2008 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 # include "incls/_precompiled.incl"
26 # include "incls/_thread.cpp.incl"
28 #ifdef DTRACE_ENABLED
30 // Only bother with this argument setup if dtrace is available
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);
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 }
52 #else // ndef DTRACE_ENABLED
54 #define DTRACE_THREAD_PROBE(probe, javathread)
56 #endif // ndef DTRACE_ENABLED
58 // Class hierarchy
59 // - Thread
60 // - VMThread
61 // - WatcherThread
62 // - ConcurrentMarkSweepThread
63 // - JavaThread
64 // - CompilerThread
66 // ======= Thread ========
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 }
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 }
100 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
101 // JavaThread
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;
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);
120 // This initial value ==> never claimed.
121 _oops_do_parity = 0;
123 // the handle mark links itself to last_handle_mark
124 new HandleMark(this);
126 // plain initialization
127 debug_only(_owned_locks = NULL;)
128 debug_only(_allow_allocation_count = 0;)
129 NOT_PRODUCT(_allow_safepoint_count = 0;)
130 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
131 _highest_lock = NULL;
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 ;
143 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
144 _suspend_flags = 0;
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 ;
152 _OnTrap = 0 ;
153 _schedctl = NULL ;
154 _Stalled = 0 ;
155 _TypeTag = 0x2BAD ;
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) ;
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 }
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.
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.
193 // initialize structure dependent on thread local storage
194 ThreadLocalStorage::set_thread(this);
196 // set up any platform-specific state.
197 os::initialize_thread();
199 }
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 }
207 Thread::~Thread() {
208 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
209 ObjectSynchronizer::omFlush (this) ;
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");
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 ;
226 delete handle_area();
228 // osthread() can be NULL, if creation of thread failed.
229 if (osthread() != NULL) os::free_thread(osthread());
231 delete _SR_lock;
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 }
245 // NOTE: dummy function for assertion purpose.
246 void Thread::run() {
247 ShouldNotReachHere();
248 }
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
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
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 }
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 }
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 }
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 }
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 //
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)
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;
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 }
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 }
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;
404 tty->print_cr(
405 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
406 jt->get_thread_name(), *bits);
408 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
409 }
410 }
411 }
412 };
413 #undef DEBUG_FALSE_BITS
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);
419 bool did_trans_retry = false; // only do thread_in_native_trans retry once
420 bool do_trans_retry; // flag to force the retry
422 *bits |= 0x00000001;
424 do {
425 do_trans_retry = false;
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 }
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 }
442 if (is_ext_suspended()) {
443 // thread is suspended
444 *bits |= 0x00000400;
445 return true;
446 }
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();
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.
498 *bits |= 0x00004000;
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;
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
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);
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
530 }
531 } while (do_trans_retry);
533 *bits |= 0x00000010;
534 return false;
535 }
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);
546 // local flag copies to minimize SR_lock hold time
547 bool is_suspended;
548 bool pending;
549 uint32_t reset_bits;
551 // set a marker so is_ext_suspend_completed() knows we are the caller
552 *bits |= 0x00010000;
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;
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
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 }
575 if (is_suspended) {
576 *bits |= 0x00040000;
577 return true;
578 }
580 for (int i = 1; i <= retries; i++) {
581 *bits = reset_bits; // reinit to only track last retry
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
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);
596 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
597 delay, bits);
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 }
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 }
613 if (is_suspended) {
614 *bits |= 0x00100000;
615 return true;
616 }
617 } // end retry loop
619 // thread did not suspend after all our retries
620 *bits |= 0x00200000;
621 return false;
622 }
624 #ifndef PRODUCT
625 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
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.
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 */
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 }
653 void Thread::interrupt(Thread* thread) {
654 trace("interrupt", thread);
655 debug_only(check_for_dangling_thread_pointer(thread);)
656 os::interrupt(thread);
657 }
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 }
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 }
686 void Thread::oops_do(OopClosure* f) {
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 }
693 void Thread::nmethods_do() {
694 }
696 void Thread::print_on(outputStream* st) const {
697 // get_priority assumes osthread initialized
698 if (osthread() != NULL) {
699 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
700 osthread()->print_on(st);
701 }
702 debug_only(if (WizardMode) print_owned_locks_on(st);)
703 }
705 // Thread::print_on_error() is called by fatal error handler. Don't use
706 // any lock or allocate memory.
707 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
708 if (is_VM_thread()) st->print("VMThread");
709 else if (is_Compiler_thread()) st->print("CompilerThread");
710 else if (is_Java_thread()) st->print("JavaThread");
711 else if (is_GC_task_thread()) st->print("GCTaskThread");
712 else if (is_Watcher_thread()) st->print("WatcherThread");
713 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
714 else st->print("Thread");
716 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
717 _stack_base - _stack_size, _stack_base);
719 if (osthread()) {
720 st->print(" [id=%d]", osthread()->thread_id());
721 }
722 }
724 #ifdef ASSERT
725 void Thread::print_owned_locks_on(outputStream* st) const {
726 Monitor *cur = _owned_locks;
727 if (cur == NULL) {
728 st->print(" (no locks) ");
729 } else {
730 st->print_cr(" Locks owned:");
731 while(cur) {
732 cur->print_on(st);
733 cur = cur->next();
734 }
735 }
736 }
738 static int ref_use_count = 0;
740 bool Thread::owns_locks_but_compiled_lock() const {
741 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
742 if (cur != Compile_lock) return true;
743 }
744 return false;
745 }
748 #endif
750 #ifndef PRODUCT
752 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
753 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
754 // no threads which allow_vm_block's are held
755 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
756 // Check if current thread is allowed to block at a safepoint
757 if (!(_allow_safepoint_count == 0))
758 fatal("Possible safepoint reached by thread that does not allow it");
759 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
760 fatal("LEAF method calling lock?");
761 }
763 #ifdef ASSERT
764 if (potential_vm_operation && is_Java_thread()
765 && !Universe::is_bootstrapping()) {
766 // Make sure we do not hold any locks that the VM thread also uses.
767 // This could potentially lead to deadlocks
768 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
769 // Threads_lock is special, since the safepoint synchronization will not start before this is
770 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
771 // since it is used to transfer control between JavaThreads and the VMThread
772 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
773 if ( (cur->allow_vm_block() &&
774 cur != Threads_lock &&
775 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
776 cur != VMOperationRequest_lock &&
777 cur != VMOperationQueue_lock) ||
778 cur->rank() == Mutex::special) {
779 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
780 }
781 }
782 }
784 if (GCALotAtAllSafepoints) {
785 // We could enter a safepoint here and thus have a gc
786 InterfaceSupport::check_gc_alot();
787 }
789 #endif
790 }
791 #endif
793 bool Thread::lock_is_in_stack(address adr) const {
794 assert(Thread::current() == this, "lock_is_in_stack can only be called from current thread");
795 // High limit: highest_lock is set during thread execution
796 // Low limit: address of the local variable dummy, rounded to 4K boundary.
797 // (The rounding helps finding threads in unsafe mode, even if the particular stack
798 // frame has been popped already. Correct as long as stacks are at least 4K long and aligned.)
799 address end = os::current_stack_pointer();
800 if (_highest_lock >= adr && adr >= end) return true;
802 return false;
803 }
806 bool Thread::is_in_stack(address adr) const {
807 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
808 address end = os::current_stack_pointer();
809 if (stack_base() >= adr && adr >= end) return true;
811 return false;
812 }
815 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
816 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
817 // used for compilation in the future. If that change is made, the need for these methods
818 // should be revisited, and they should be removed if possible.
820 bool Thread::is_lock_owned(address adr) const {
821 if (lock_is_in_stack(adr) ) return true;
822 return false;
823 }
825 bool Thread::set_as_starting_thread() {
826 // NOTE: this must be called inside the main thread.
827 return os::create_main_thread((JavaThread*)this);
828 }
830 static void initialize_class(symbolHandle class_name, TRAPS) {
831 klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
832 instanceKlass::cast(klass)->initialize(CHECK);
833 }
836 // Creates the initial ThreadGroup
837 static Handle create_initial_thread_group(TRAPS) {
838 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_ThreadGroup(), true, CHECK_NH);
839 instanceKlassHandle klass (THREAD, k);
841 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
842 {
843 JavaValue result(T_VOID);
844 JavaCalls::call_special(&result,
845 system_instance,
846 klass,
847 vmSymbolHandles::object_initializer_name(),
848 vmSymbolHandles::void_method_signature(),
849 CHECK_NH);
850 }
851 Universe::set_system_thread_group(system_instance());
853 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
854 {
855 JavaValue result(T_VOID);
856 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
857 JavaCalls::call_special(&result,
858 main_instance,
859 klass,
860 vmSymbolHandles::object_initializer_name(),
861 vmSymbolHandles::threadgroup_string_void_signature(),
862 system_instance,
863 string,
864 CHECK_NH);
865 }
866 return main_instance;
867 }
869 // Creates the initial Thread
870 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
871 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK_NULL);
872 instanceKlassHandle klass (THREAD, k);
873 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
875 java_lang_Thread::set_thread(thread_oop(), thread);
876 java_lang_Thread::set_priority(thread_oop(), NormPriority);
877 thread->set_threadObj(thread_oop());
879 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
881 JavaValue result(T_VOID);
882 JavaCalls::call_special(&result, thread_oop,
883 klass,
884 vmSymbolHandles::object_initializer_name(),
885 vmSymbolHandles::threadgroup_string_void_signature(),
886 thread_group,
887 string,
888 CHECK_NULL);
889 return thread_oop();
890 }
892 static void call_initializeSystemClass(TRAPS) {
893 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
894 instanceKlassHandle klass (THREAD, k);
896 JavaValue result(T_VOID);
897 JavaCalls::call_static(&result, klass, vmSymbolHandles::initializeSystemClass_name(),
898 vmSymbolHandles::void_method_signature(), CHECK);
899 }
901 static void reset_vm_info_property(TRAPS) {
902 // the vm info string
903 ResourceMark rm(THREAD);
904 const char *vm_info = VM_Version::vm_info_string();
906 // java.lang.System class
907 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
908 instanceKlassHandle klass (THREAD, k);
910 // setProperty arguments
911 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
912 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
914 // return value
915 JavaValue r(T_OBJECT);
917 // public static String setProperty(String key, String value);
918 JavaCalls::call_static(&r,
919 klass,
920 vmSymbolHandles::setProperty_name(),
921 vmSymbolHandles::string_string_string_signature(),
922 key_str,
923 value_str,
924 CHECK);
925 }
928 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
929 assert(thread_group.not_null(), "thread group should be specified");
930 assert(threadObj() == NULL, "should only create Java thread object once");
932 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
933 instanceKlassHandle klass (THREAD, k);
934 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
936 java_lang_Thread::set_thread(thread_oop(), this);
937 java_lang_Thread::set_priority(thread_oop(), NormPriority);
938 set_threadObj(thread_oop());
940 JavaValue result(T_VOID);
941 if (thread_name != NULL) {
942 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
943 // Thread gets assigned specified name and null target
944 JavaCalls::call_special(&result,
945 thread_oop,
946 klass,
947 vmSymbolHandles::object_initializer_name(),
948 vmSymbolHandles::threadgroup_string_void_signature(),
949 thread_group, // Argument 1
950 name, // Argument 2
951 THREAD);
952 } else {
953 // Thread gets assigned name "Thread-nnn" and null target
954 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
955 JavaCalls::call_special(&result,
956 thread_oop,
957 klass,
958 vmSymbolHandles::object_initializer_name(),
959 vmSymbolHandles::threadgroup_runnable_void_signature(),
960 thread_group, // Argument 1
961 Handle(), // Argument 2
962 THREAD);
963 }
966 if (daemon) {
967 java_lang_Thread::set_daemon(thread_oop());
968 }
970 if (HAS_PENDING_EXCEPTION) {
971 return;
972 }
974 KlassHandle group(this, SystemDictionary::threadGroup_klass());
975 Handle threadObj(this, this->threadObj());
977 JavaCalls::call_special(&result,
978 thread_group,
979 group,
980 vmSymbolHandles::add_method_name(),
981 vmSymbolHandles::thread_void_signature(),
982 threadObj, // Arg 1
983 THREAD);
986 }
988 // NamedThread -- non-JavaThread subclasses with multiple
989 // uniquely named instances should derive from this.
990 NamedThread::NamedThread() : Thread() {
991 _name = NULL;
992 }
994 NamedThread::~NamedThread() {
995 if (_name != NULL) {
996 FREE_C_HEAP_ARRAY(char, _name);
997 _name = NULL;
998 }
999 }
1001 void NamedThread::set_name(const char* format, ...) {
1002 guarantee(_name == NULL, "Only get to set name once.");
1003 _name = NEW_C_HEAP_ARRAY(char, max_name_len);
1004 guarantee(_name != NULL, "alloc failure");
1005 va_list ap;
1006 va_start(ap, format);
1007 jio_vsnprintf(_name, max_name_len, format, ap);
1008 va_end(ap);
1009 }
1011 // ======= WatcherThread ========
1013 // The watcher thread exists to simulate timer interrupts. It should
1014 // be replaced by an abstraction over whatever native support for
1015 // timer interrupts exists on the platform.
1017 WatcherThread* WatcherThread::_watcher_thread = NULL;
1018 bool WatcherThread::_should_terminate = false;
1020 WatcherThread::WatcherThread() : Thread() {
1021 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1022 if (os::create_thread(this, os::watcher_thread)) {
1023 _watcher_thread = this;
1025 // Set the watcher thread to the highest OS priority which should not be
1026 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1027 // is created. The only normal thread using this priority is the reference
1028 // handler thread, which runs for very short intervals only.
1029 // If the VMThread's priority is not lower than the WatcherThread profiling
1030 // will be inaccurate.
1031 os::set_priority(this, MaxPriority);
1032 if (!DisableStartThread) {
1033 os::start_thread(this);
1034 }
1035 }
1036 }
1038 void WatcherThread::run() {
1039 assert(this == watcher_thread(), "just checking");
1041 this->record_stack_base_and_size();
1042 this->initialize_thread_local_storage();
1043 this->set_active_handles(JNIHandleBlock::allocate_block());
1044 while(!_should_terminate) {
1045 assert(watcher_thread() == Thread::current(), "thread consistency check");
1046 assert(watcher_thread() == this, "thread consistency check");
1048 // Calculate how long it'll be until the next PeriodicTask work
1049 // should be done, and sleep that amount of time.
1050 const size_t time_to_wait = PeriodicTask::time_to_wait();
1051 os::sleep(this, time_to_wait, false);
1053 if (is_error_reported()) {
1054 // A fatal error has happened, the error handler(VMError::report_and_die)
1055 // should abort JVM after creating an error log file. However in some
1056 // rare cases, the error handler itself might deadlock. Here we try to
1057 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1058 //
1059 // This code is in WatcherThread because WatcherThread wakes up
1060 // periodically so the fatal error handler doesn't need to do anything;
1061 // also because the WatcherThread is less likely to crash than other
1062 // threads.
1064 for (;;) {
1065 if (!ShowMessageBoxOnError
1066 && (OnError == NULL || OnError[0] == '\0')
1067 && Arguments::abort_hook() == NULL) {
1068 os::sleep(this, 2 * 60 * 1000, false);
1069 fdStream err(defaultStream::output_fd());
1070 err.print_raw_cr("# [ timer expired, abort... ]");
1071 // skip atexit/vm_exit/vm_abort hooks
1072 os::die();
1073 }
1075 // Wake up 5 seconds later, the fatal handler may reset OnError or
1076 // ShowMessageBoxOnError when it is ready to abort.
1077 os::sleep(this, 5 * 1000, false);
1078 }
1079 }
1081 PeriodicTask::real_time_tick(time_to_wait);
1083 // If we have no more tasks left due to dynamic disenrollment,
1084 // shut down the thread since we don't currently support dynamic enrollment
1085 if (PeriodicTask::num_tasks() == 0) {
1086 _should_terminate = true;
1087 }
1088 }
1090 // Signal that it is terminated
1091 {
1092 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1093 _watcher_thread = NULL;
1094 Terminator_lock->notify();
1095 }
1097 // Thread destructor usually does this..
1098 ThreadLocalStorage::set_thread(NULL);
1099 }
1101 void WatcherThread::start() {
1102 if (watcher_thread() == NULL) {
1103 _should_terminate = false;
1104 // Create the single instance of WatcherThread
1105 new WatcherThread();
1106 }
1107 }
1109 void WatcherThread::stop() {
1110 // it is ok to take late safepoints here, if needed
1111 MutexLocker mu(Terminator_lock);
1112 _should_terminate = true;
1113 while(watcher_thread() != NULL) {
1114 // This wait should make safepoint checks, wait without a timeout,
1115 // and wait as a suspend-equivalent condition.
1116 //
1117 // Note: If the FlatProfiler is running, then this thread is waiting
1118 // for the WatcherThread to terminate and the WatcherThread, via the
1119 // FlatProfiler task, is waiting for the external suspend request on
1120 // this thread to complete. wait_for_ext_suspend_completion() will
1121 // eventually timeout, but that takes time. Making this wait a
1122 // suspend-equivalent condition solves that timeout problem.
1123 //
1124 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1125 Mutex::_as_suspend_equivalent_flag);
1126 }
1127 }
1129 void WatcherThread::print_on(outputStream* st) const {
1130 st->print("\"%s\" ", name());
1131 Thread::print_on(st);
1132 st->cr();
1133 }
1135 // ======= JavaThread ========
1137 // A JavaThread is a normal Java thread
1139 void JavaThread::initialize() {
1140 // Initialize fields
1142 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1143 set_claimed_par_id(-1);
1145 set_saved_exception_pc(NULL);
1146 set_threadObj(NULL);
1147 _anchor.clear();
1148 set_entry_point(NULL);
1149 set_jni_functions(jni_functions());
1150 set_callee_target(NULL);
1151 set_vm_result(NULL);
1152 set_vm_result_2(NULL);
1153 set_vframe_array_head(NULL);
1154 set_vframe_array_last(NULL);
1155 set_deferred_locals(NULL);
1156 set_deopt_mark(NULL);
1157 clear_must_deopt_id();
1158 set_monitor_chunks(NULL);
1159 set_next(NULL);
1160 set_thread_state(_thread_new);
1161 _terminated = _not_terminated;
1162 _privileged_stack_top = NULL;
1163 _array_for_gc = NULL;
1164 _suspend_equivalent = false;
1165 _in_deopt_handler = 0;
1166 _doing_unsafe_access = false;
1167 _stack_guard_state = stack_guard_unused;
1168 _exception_oop = NULL;
1169 _exception_pc = 0;
1170 _exception_handler_pc = 0;
1171 _exception_stack_size = 0;
1172 _jvmti_thread_state= NULL;
1173 _jvmti_get_loaded_classes_closure = NULL;
1174 _interp_only_mode = 0;
1175 _special_runtime_exit_condition = _no_async_condition;
1176 _pending_async_exception = NULL;
1177 _is_compiling = false;
1178 _thread_stat = NULL;
1179 _thread_stat = new ThreadStatistics();
1180 _blocked_on_compilation = false;
1181 _jni_active_critical = 0;
1182 _do_not_unlock_if_synchronized = false;
1183 _cached_monitor_info = NULL;
1184 _parker = Parker::Allocate(this) ;
1186 #ifndef PRODUCT
1187 _jmp_ring_index = 0;
1188 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1189 record_jump(NULL, NULL, NULL, 0);
1190 }
1191 #endif /* PRODUCT */
1193 set_thread_profiler(NULL);
1194 if (FlatProfiler::is_active()) {
1195 // This is where we would decide to either give each thread it's own profiler
1196 // or use one global one from FlatProfiler,
1197 // or up to some count of the number of profiled threads, etc.
1198 ThreadProfiler* pp = new ThreadProfiler();
1199 pp->engage();
1200 set_thread_profiler(pp);
1201 }
1203 // Setup safepoint state info for this thread
1204 ThreadSafepointState::create(this);
1206 debug_only(_java_call_counter = 0);
1208 // JVMTI PopFrame support
1209 _popframe_condition = popframe_inactive;
1210 _popframe_preserved_args = NULL;
1211 _popframe_preserved_args_size = 0;
1213 pd_initialize();
1214 }
1216 #ifndef SERIALGC
1217 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1218 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1219 #endif // !SERIALGC
1221 JavaThread::JavaThread(bool is_attaching) :
1222 Thread()
1223 #ifndef SERIALGC
1224 , _satb_mark_queue(&_satb_mark_queue_set),
1225 _dirty_card_queue(&_dirty_card_queue_set)
1226 #endif // !SERIALGC
1227 {
1228 initialize();
1229 _is_attaching = is_attaching;
1230 }
1232 bool JavaThread::reguard_stack(address cur_sp) {
1233 if (_stack_guard_state != stack_guard_yellow_disabled) {
1234 return true; // Stack already guarded or guard pages not needed.
1235 }
1237 if (register_stack_overflow()) {
1238 // For those architectures which have separate register and
1239 // memory stacks, we must check the register stack to see if
1240 // it has overflowed.
1241 return false;
1242 }
1244 // Java code never executes within the yellow zone: the latter is only
1245 // there to provoke an exception during stack banging. If java code
1246 // is executing there, either StackShadowPages should be larger, or
1247 // some exception code in c1, c2 or the interpreter isn't unwinding
1248 // when it should.
1249 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1251 enable_stack_yellow_zone();
1252 return true;
1253 }
1255 bool JavaThread::reguard_stack(void) {
1256 return reguard_stack(os::current_stack_pointer());
1257 }
1260 void JavaThread::block_if_vm_exited() {
1261 if (_terminated == _vm_exited) {
1262 // _vm_exited is set at safepoint, and Threads_lock is never released
1263 // we will block here forever
1264 Threads_lock->lock_without_safepoint_check();
1265 ShouldNotReachHere();
1266 }
1267 }
1270 // Remove this ifdef when C1 is ported to the compiler interface.
1271 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1273 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1274 Thread()
1275 #ifndef SERIALGC
1276 , _satb_mark_queue(&_satb_mark_queue_set),
1277 _dirty_card_queue(&_dirty_card_queue_set)
1278 #endif // !SERIALGC
1279 {
1280 if (TraceThreadEvents) {
1281 tty->print_cr("creating thread %p", this);
1282 }
1283 initialize();
1284 _is_attaching = false;
1285 set_entry_point(entry_point);
1286 // Create the native thread itself.
1287 // %note runtime_23
1288 os::ThreadType thr_type = os::java_thread;
1289 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1290 os::java_thread;
1291 os::create_thread(this, thr_type, stack_sz);
1293 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1294 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1295 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1296 // the exception consists of creating the exception object & initializing it, initialization
1297 // will leave the VM via a JavaCall and then all locks must be unlocked).
1298 //
1299 // The thread is still suspended when we reach here. Thread must be explicit started
1300 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1301 // by calling Threads:add. The reason why this is not done here, is because the thread
1302 // object must be fully initialized (take a look at JVM_Start)
1303 }
1305 JavaThread::~JavaThread() {
1306 if (TraceThreadEvents) {
1307 tty->print_cr("terminate thread %p", this);
1308 }
1310 // JSR166 -- return the parker to the free list
1311 Parker::Release(_parker);
1312 _parker = NULL ;
1314 // Free any remaining previous UnrollBlock
1315 vframeArray* old_array = vframe_array_last();
1317 if (old_array != NULL) {
1318 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1319 old_array->set_unroll_block(NULL);
1320 delete old_info;
1321 delete old_array;
1322 }
1324 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1325 if (deferred != NULL) {
1326 // This can only happen if thread is destroyed before deoptimization occurs.
1327 assert(deferred->length() != 0, "empty array!");
1328 do {
1329 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1330 deferred->remove_at(0);
1331 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1332 delete dlv;
1333 } while (deferred->length() != 0);
1334 delete deferred;
1335 }
1337 // All Java related clean up happens in exit
1338 ThreadSafepointState::destroy(this);
1339 if (_thread_profiler != NULL) delete _thread_profiler;
1340 if (_thread_stat != NULL) delete _thread_stat;
1341 }
1344 // The first routine called by a new Java thread
1345 void JavaThread::run() {
1346 // initialize thread-local alloc buffer related fields
1347 this->initialize_tlab();
1349 // used to test validitity of stack trace backs
1350 this->record_base_of_stack_pointer();
1352 // Record real stack base and size.
1353 this->record_stack_base_and_size();
1355 // Initialize thread local storage; set before calling MutexLocker
1356 this->initialize_thread_local_storage();
1358 this->create_stack_guard_pages();
1360 // Thread is now sufficient initialized to be handled by the safepoint code as being
1361 // in the VM. Change thread state from _thread_new to _thread_in_vm
1362 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1364 assert(JavaThread::current() == this, "sanity check");
1365 assert(!Thread::current()->owns_locks(), "sanity check");
1367 DTRACE_THREAD_PROBE(start, this);
1369 // This operation might block. We call that after all safepoint checks for a new thread has
1370 // been completed.
1371 this->set_active_handles(JNIHandleBlock::allocate_block());
1373 if (JvmtiExport::should_post_thread_life()) {
1374 JvmtiExport::post_thread_start(this);
1375 }
1377 // We call another function to do the rest so we are sure that the stack addresses used
1378 // from there will be lower than the stack base just computed
1379 thread_main_inner();
1381 // Note, thread is no longer valid at this point!
1382 }
1385 void JavaThread::thread_main_inner() {
1386 assert(JavaThread::current() == this, "sanity check");
1387 assert(this->threadObj() != NULL, "just checking");
1389 // Execute thread entry point. If this thread is being asked to restart,
1390 // or has been stopped before starting, do not reexecute entry point.
1391 // Note: Due to JVM_StopThread we can have pending exceptions already!
1392 if (!this->has_pending_exception() && !java_lang_Thread::is_stillborn(this->threadObj())) {
1393 // enter the thread's entry point only if we have no pending exceptions
1394 HandleMark hm(this);
1395 this->entry_point()(this, this);
1396 }
1398 DTRACE_THREAD_PROBE(stop, this);
1400 this->exit(false);
1401 delete this;
1402 }
1405 static void ensure_join(JavaThread* thread) {
1406 // We do not need to grap the Threads_lock, since we are operating on ourself.
1407 Handle threadObj(thread, thread->threadObj());
1408 assert(threadObj.not_null(), "java thread object must exist");
1409 ObjectLocker lock(threadObj, thread);
1410 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1411 thread->clear_pending_exception();
1412 // It is of profound importance that we set the stillborn bit and reset the thread object,
1413 // before we do the notify. Since, changing these two variable will make JVM_IsAlive return
1414 // false. So in case another thread is doing a join on this thread , it will detect that the thread
1415 // is dead when it gets notified.
1416 java_lang_Thread::set_stillborn(threadObj());
1417 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1418 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1419 java_lang_Thread::set_thread(threadObj(), NULL);
1420 lock.notify_all(thread);
1421 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1422 thread->clear_pending_exception();
1423 }
1426 // For any new cleanup additions, please check to see if they need to be applied to
1427 // cleanup_failed_attach_current_thread as well.
1428 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1429 assert(this == JavaThread::current(), "thread consistency check");
1430 if (!InitializeJavaLangSystem) return;
1432 HandleMark hm(this);
1433 Handle uncaught_exception(this, this->pending_exception());
1434 this->clear_pending_exception();
1435 Handle threadObj(this, this->threadObj());
1436 assert(threadObj.not_null(), "Java thread object should be created");
1438 if (get_thread_profiler() != NULL) {
1439 get_thread_profiler()->disengage();
1440 ResourceMark rm;
1441 get_thread_profiler()->print(get_thread_name());
1442 }
1445 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1446 {
1447 EXCEPTION_MARK;
1449 CLEAR_PENDING_EXCEPTION;
1450 }
1451 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1452 // has to be fixed by a runtime query method
1453 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1454 // JSR-166: change call from from ThreadGroup.uncaughtException to
1455 // java.lang.Thread.dispatchUncaughtException
1456 if (uncaught_exception.not_null()) {
1457 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1458 Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT",
1459 (address)uncaught_exception(), (address)threadObj(), (address)group());
1460 {
1461 EXCEPTION_MARK;
1462 // Check if the method Thread.dispatchUncaughtException() exists. If so
1463 // call it. Otherwise we have an older library without the JSR-166 changes,
1464 // so call ThreadGroup.uncaughtException()
1465 KlassHandle recvrKlass(THREAD, threadObj->klass());
1466 CallInfo callinfo;
1467 KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass());
1468 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1469 vmSymbolHandles::dispatchUncaughtException_name(),
1470 vmSymbolHandles::throwable_void_signature(),
1471 KlassHandle(), false, false, THREAD);
1472 CLEAR_PENDING_EXCEPTION;
1473 methodHandle method = callinfo.selected_method();
1474 if (method.not_null()) {
1475 JavaValue result(T_VOID);
1476 JavaCalls::call_virtual(&result,
1477 threadObj, thread_klass,
1478 vmSymbolHandles::dispatchUncaughtException_name(),
1479 vmSymbolHandles::throwable_void_signature(),
1480 uncaught_exception,
1481 THREAD);
1482 } else {
1483 KlassHandle thread_group(THREAD, SystemDictionary::threadGroup_klass());
1484 JavaValue result(T_VOID);
1485 JavaCalls::call_virtual(&result,
1486 group, thread_group,
1487 vmSymbolHandles::uncaughtException_name(),
1488 vmSymbolHandles::thread_throwable_void_signature(),
1489 threadObj, // Arg 1
1490 uncaught_exception, // Arg 2
1491 THREAD);
1492 }
1493 CLEAR_PENDING_EXCEPTION;
1494 }
1495 }
1497 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1498 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1499 // is deprecated anyhow.
1500 { int count = 3;
1501 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1502 EXCEPTION_MARK;
1503 JavaValue result(T_VOID);
1504 KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass());
1505 JavaCalls::call_virtual(&result,
1506 threadObj, thread_klass,
1507 vmSymbolHandles::exit_method_name(),
1508 vmSymbolHandles::void_method_signature(),
1509 THREAD);
1510 CLEAR_PENDING_EXCEPTION;
1511 }
1512 }
1514 // notify JVMTI
1515 if (JvmtiExport::should_post_thread_life()) {
1516 JvmtiExport::post_thread_end(this);
1517 }
1519 // We have notified the agents that we are exiting, before we go on,
1520 // we must check for a pending external suspend request and honor it
1521 // in order to not surprise the thread that made the suspend request.
1522 while (true) {
1523 {
1524 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1525 if (!is_external_suspend()) {
1526 set_terminated(_thread_exiting);
1527 ThreadService::current_thread_exiting(this);
1528 break;
1529 }
1530 // Implied else:
1531 // Things get a little tricky here. We have a pending external
1532 // suspend request, but we are holding the SR_lock so we
1533 // can't just self-suspend. So we temporarily drop the lock
1534 // and then self-suspend.
1535 }
1537 ThreadBlockInVM tbivm(this);
1538 java_suspend_self();
1540 // We're done with this suspend request, but we have to loop around
1541 // and check again. Eventually we will get SR_lock without a pending
1542 // external suspend request and will be able to mark ourselves as
1543 // exiting.
1544 }
1545 // no more external suspends are allowed at this point
1546 } else {
1547 // before_exit() has already posted JVMTI THREAD_END events
1548 }
1550 // Notify waiters on thread object. This has to be done after exit() is called
1551 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1552 // group should have the destroyed bit set before waiters are notified).
1553 ensure_join(this);
1554 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1556 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1557 // held by this thread must be released. A detach operation must only
1558 // get here if there are no Java frames on the stack. Therefore, any
1559 // owned monitors at this point MUST be JNI-acquired monitors which are
1560 // pre-inflated and in the monitor cache.
1561 //
1562 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1563 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1564 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1565 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1566 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1567 }
1569 // These things needs to be done while we are still a Java Thread. Make sure that thread
1570 // is in a consistent state, in case GC happens
1571 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1573 if (active_handles() != NULL) {
1574 JNIHandleBlock* block = active_handles();
1575 set_active_handles(NULL);
1576 JNIHandleBlock::release_block(block);
1577 }
1579 if (free_handle_block() != NULL) {
1580 JNIHandleBlock* block = free_handle_block();
1581 set_free_handle_block(NULL);
1582 JNIHandleBlock::release_block(block);
1583 }
1585 // These have to be removed while this is still a valid thread.
1586 remove_stack_guard_pages();
1588 if (UseTLAB) {
1589 tlab().make_parsable(true); // retire TLAB
1590 }
1592 if (jvmti_thread_state() != NULL) {
1593 JvmtiExport::cleanup_thread(this);
1594 }
1596 #ifndef SERIALGC
1597 // We must flush G1-related buffers before removing a thread from
1598 // the list of active threads.
1599 if (UseG1GC) {
1600 flush_barrier_queues();
1601 }
1602 #endif
1604 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1605 Threads::remove(this);
1606 }
1608 #ifndef SERIALGC
1609 // Flush G1-related queues.
1610 void JavaThread::flush_barrier_queues() {
1611 satb_mark_queue().flush();
1612 dirty_card_queue().flush();
1613 }
1614 #endif
1616 void JavaThread::cleanup_failed_attach_current_thread() {
1617 if (get_thread_profiler() != NULL) {
1618 get_thread_profiler()->disengage();
1619 ResourceMark rm;
1620 get_thread_profiler()->print(get_thread_name());
1621 }
1623 if (active_handles() != NULL) {
1624 JNIHandleBlock* block = active_handles();
1625 set_active_handles(NULL);
1626 JNIHandleBlock::release_block(block);
1627 }
1629 if (free_handle_block() != NULL) {
1630 JNIHandleBlock* block = free_handle_block();
1631 set_free_handle_block(NULL);
1632 JNIHandleBlock::release_block(block);
1633 }
1635 if (UseTLAB) {
1636 tlab().make_parsable(true); // retire TLAB, if any
1637 }
1639 #ifndef SERIALGC
1640 if (UseG1GC) {
1641 flush_barrier_queues();
1642 }
1643 #endif
1645 Threads::remove(this);
1646 delete this;
1647 }
1652 JavaThread* JavaThread::active() {
1653 Thread* thread = ThreadLocalStorage::thread();
1654 assert(thread != NULL, "just checking");
1655 if (thread->is_Java_thread()) {
1656 return (JavaThread*) thread;
1657 } else {
1658 assert(thread->is_VM_thread(), "this must be a vm thread");
1659 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1660 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1661 assert(ret->is_Java_thread(), "must be a Java thread");
1662 return ret;
1663 }
1664 }
1666 bool JavaThread::is_lock_owned(address adr) const {
1667 if (lock_is_in_stack(adr)) return true;
1669 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1670 if (chunk->contains(adr)) return true;
1671 }
1673 return false;
1674 }
1677 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1678 chunk->set_next(monitor_chunks());
1679 set_monitor_chunks(chunk);
1680 }
1682 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1683 guarantee(monitor_chunks() != NULL, "must be non empty");
1684 if (monitor_chunks() == chunk) {
1685 set_monitor_chunks(chunk->next());
1686 } else {
1687 MonitorChunk* prev = monitor_chunks();
1688 while (prev->next() != chunk) prev = prev->next();
1689 prev->set_next(chunk->next());
1690 }
1691 }
1693 // JVM support.
1695 // Note: this function shouldn't block if it's called in
1696 // _thread_in_native_trans state (such as from
1697 // check_special_condition_for_native_trans()).
1698 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1700 if (has_last_Java_frame() && has_async_condition()) {
1701 // If we are at a polling page safepoint (not a poll return)
1702 // then we must defer async exception because live registers
1703 // will be clobbered by the exception path. Poll return is
1704 // ok because the call we a returning from already collides
1705 // with exception handling registers and so there is no issue.
1706 // (The exception handling path kills call result registers but
1707 // this is ok since the exception kills the result anyway).
1709 if (is_at_poll_safepoint()) {
1710 // if the code we are returning to has deoptimized we must defer
1711 // the exception otherwise live registers get clobbered on the
1712 // exception path before deoptimization is able to retrieve them.
1713 //
1714 RegisterMap map(this, false);
1715 frame caller_fr = last_frame().sender(&map);
1716 assert(caller_fr.is_compiled_frame(), "what?");
1717 if (caller_fr.is_deoptimized_frame()) {
1718 if (TraceExceptions) {
1719 ResourceMark rm;
1720 tty->print_cr("deferred async exception at compiled safepoint");
1721 }
1722 return;
1723 }
1724 }
1725 }
1727 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
1728 if (condition == _no_async_condition) {
1729 // Conditions have changed since has_special_runtime_exit_condition()
1730 // was called:
1731 // - if we were here only because of an external suspend request,
1732 // then that was taken care of above (or cancelled) so we are done
1733 // - if we were here because of another async request, then it has
1734 // been cleared between the has_special_runtime_exit_condition()
1735 // and now so again we are done
1736 return;
1737 }
1739 // Check for pending async. exception
1740 if (_pending_async_exception != NULL) {
1741 // Only overwrite an already pending exception, if it is not a threadDeath.
1742 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::threaddeath_klass())) {
1744 // We cannot call Exceptions::_throw(...) here because we cannot block
1745 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
1747 if (TraceExceptions) {
1748 ResourceMark rm;
1749 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
1750 if (has_last_Java_frame() ) {
1751 frame f = last_frame();
1752 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
1753 }
1754 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1755 }
1756 _pending_async_exception = NULL;
1757 clear_has_async_exception();
1758 }
1759 }
1761 if (check_unsafe_error &&
1762 condition == _async_unsafe_access_error && !has_pending_exception()) {
1763 condition = _no_async_condition; // done
1764 switch (thread_state()) {
1765 case _thread_in_vm:
1766 {
1767 JavaThread* THREAD = this;
1768 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1769 }
1770 case _thread_in_native:
1771 {
1772 ThreadInVMfromNative tiv(this);
1773 JavaThread* THREAD = this;
1774 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1775 }
1776 case _thread_in_Java:
1777 {
1778 ThreadInVMfromJava tiv(this);
1779 JavaThread* THREAD = this;
1780 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
1781 }
1782 default:
1783 ShouldNotReachHere();
1784 }
1785 }
1787 assert(condition == _no_async_condition || has_pending_exception() ||
1788 (!check_unsafe_error && condition == _async_unsafe_access_error),
1789 "must have handled the async condition, if no exception");
1790 }
1792 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
1793 //
1794 // Check for pending external suspend. Internal suspend requests do
1795 // not use handle_special_runtime_exit_condition().
1796 // If JNIEnv proxies are allowed, don't self-suspend if the target
1797 // thread is not the current thread. In older versions of jdbx, jdbx
1798 // threads could call into the VM with another thread's JNIEnv so we
1799 // can be here operating on behalf of a suspended thread (4432884).
1800 bool do_self_suspend = is_external_suspend_with_lock();
1801 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
1802 //
1803 // Because thread is external suspended the safepoint code will count
1804 // thread as at a safepoint. This can be odd because we can be here
1805 // as _thread_in_Java which would normally transition to _thread_blocked
1806 // at a safepoint. We would like to mark the thread as _thread_blocked
1807 // before calling java_suspend_self like all other callers of it but
1808 // we must then observe proper safepoint protocol. (We can't leave
1809 // _thread_blocked with a safepoint in progress). However we can be
1810 // here as _thread_in_native_trans so we can't use a normal transition
1811 // constructor/destructor pair because they assert on that type of
1812 // transition. We could do something like:
1813 //
1814 // JavaThreadState state = thread_state();
1815 // set_thread_state(_thread_in_vm);
1816 // {
1817 // ThreadBlockInVM tbivm(this);
1818 // java_suspend_self()
1819 // }
1820 // set_thread_state(_thread_in_vm_trans);
1821 // if (safepoint) block;
1822 // set_thread_state(state);
1823 //
1824 // but that is pretty messy. Instead we just go with the way the
1825 // code has worked before and note that this is the only path to
1826 // java_suspend_self that doesn't put the thread in _thread_blocked
1827 // mode.
1829 frame_anchor()->make_walkable(this);
1830 java_suspend_self();
1832 // We might be here for reasons in addition to the self-suspend request
1833 // so check for other async requests.
1834 }
1836 if (check_asyncs) {
1837 check_and_handle_async_exceptions();
1838 }
1839 }
1841 void JavaThread::send_thread_stop(oop java_throwable) {
1842 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
1843 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
1844 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
1846 // Do not throw asynchronous exceptions against the compiler thread
1847 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
1848 if (is_Compiler_thread()) return;
1850 // This is a change from JDK 1.1, but JDK 1.2 will also do it:
1851 if (java_throwable->is_a(SystemDictionary::threaddeath_klass())) {
1852 java_lang_Thread::set_stillborn(threadObj());
1853 }
1855 {
1856 // Actually throw the Throwable against the target Thread - however
1857 // only if there is no thread death exception installed already.
1858 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::threaddeath_klass())) {
1859 // If the topmost frame is a runtime stub, then we are calling into
1860 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1861 // must deoptimize the caller before continuing, as the compiled exception handler table
1862 // may not be valid
1863 if (has_last_Java_frame()) {
1864 frame f = last_frame();
1865 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
1866 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
1867 RegisterMap reg_map(this, UseBiasedLocking);
1868 frame compiled_frame = f.sender(®_map);
1869 if (compiled_frame.can_be_deoptimized()) {
1870 Deoptimization::deoptimize(this, compiled_frame, ®_map);
1871 }
1872 }
1873 }
1875 // Set async. pending exception in thread.
1876 set_pending_async_exception(java_throwable);
1878 if (TraceExceptions) {
1879 ResourceMark rm;
1880 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1881 }
1882 // for AbortVMOnException flag
1883 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
1884 }
1885 }
1888 // Interrupt thread so it will wake up from a potential wait()
1889 Thread::interrupt(this);
1890 }
1892 // External suspension mechanism.
1893 //
1894 // Tell the VM to suspend a thread when ever it knows that it does not hold on
1895 // to any VM_locks and it is at a transition
1896 // Self-suspension will happen on the transition out of the vm.
1897 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
1898 //
1899 // Guarantees on return:
1900 // + Target thread will not execute any new bytecode (that's why we need to
1901 // force a safepoint)
1902 // + Target thread will not enter any new monitors
1903 //
1904 void JavaThread::java_suspend() {
1905 { MutexLocker mu(Threads_lock);
1906 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
1907 return;
1908 }
1909 }
1911 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1912 if (!is_external_suspend()) {
1913 // a racing resume has cancelled us; bail out now
1914 return;
1915 }
1917 // suspend is done
1918 uint32_t debug_bits = 0;
1919 // Warning: is_ext_suspend_completed() may temporarily drop the
1920 // SR_lock to allow the thread to reach a stable thread state if
1921 // it is currently in a transient thread state.
1922 if (is_ext_suspend_completed(false /* !called_by_wait */,
1923 SuspendRetryDelay, &debug_bits) ) {
1924 return;
1925 }
1926 }
1928 VM_ForceSafepoint vm_suspend;
1929 VMThread::execute(&vm_suspend);
1930 }
1932 // Part II of external suspension.
1933 // A JavaThread self suspends when it detects a pending external suspend
1934 // request. This is usually on transitions. It is also done in places
1935 // where continuing to the next transition would surprise the caller,
1936 // e.g., monitor entry.
1937 //
1938 // Returns the number of times that the thread self-suspended.
1939 //
1940 // Note: DO NOT call java_suspend_self() when you just want to block current
1941 // thread. java_suspend_self() is the second stage of cooperative
1942 // suspension for external suspend requests and should only be used
1943 // to complete an external suspend request.
1944 //
1945 int JavaThread::java_suspend_self() {
1946 int ret = 0;
1948 // we are in the process of exiting so don't suspend
1949 if (is_exiting()) {
1950 clear_external_suspend();
1951 return ret;
1952 }
1954 assert(_anchor.walkable() ||
1955 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
1956 "must have walkable stack");
1958 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1960 assert(!this->is_any_suspended(),
1961 "a thread trying to self-suspend should not already be suspended");
1963 if (this->is_suspend_equivalent()) {
1964 // If we are self-suspending as a result of the lifting of a
1965 // suspend equivalent condition, then the suspend_equivalent
1966 // flag is not cleared until we set the ext_suspended flag so
1967 // that wait_for_ext_suspend_completion() returns consistent
1968 // results.
1969 this->clear_suspend_equivalent();
1970 }
1972 // A racing resume may have cancelled us before we grabbed SR_lock
1973 // above. Or another external suspend request could be waiting for us
1974 // by the time we return from SR_lock()->wait(). The thread
1975 // that requested the suspension may already be trying to walk our
1976 // stack and if we return now, we can change the stack out from under
1977 // it. This would be a "bad thing (TM)" and cause the stack walker
1978 // to crash. We stay self-suspended until there are no more pending
1979 // external suspend requests.
1980 while (is_external_suspend()) {
1981 ret++;
1982 this->set_ext_suspended();
1984 // _ext_suspended flag is cleared by java_resume()
1985 while (is_ext_suspended()) {
1986 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
1987 }
1988 }
1990 return ret;
1991 }
1993 #ifdef ASSERT
1994 // verify the JavaThread has not yet been published in the Threads::list, and
1995 // hence doesn't need protection from concurrent access at this stage
1996 void JavaThread::verify_not_published() {
1997 if (!Threads_lock->owned_by_self()) {
1998 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
1999 assert( !Threads::includes(this),
2000 "java thread shouldn't have been published yet!");
2001 }
2002 else {
2003 assert( !Threads::includes(this),
2004 "java thread shouldn't have been published yet!");
2005 }
2006 }
2007 #endif
2009 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2010 // progress or when _suspend_flags is non-zero.
2011 // Current thread needs to self-suspend if there is a suspend request and/or
2012 // block if a safepoint is in progress.
2013 // Async exception ISN'T checked.
2014 // Note only the ThreadInVMfromNative transition can call this function
2015 // directly and when thread state is _thread_in_native_trans
2016 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2017 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2019 JavaThread *curJT = JavaThread::current();
2020 bool do_self_suspend = thread->is_external_suspend();
2022 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2024 // If JNIEnv proxies are allowed, don't self-suspend if the target
2025 // thread is not the current thread. In older versions of jdbx, jdbx
2026 // threads could call into the VM with another thread's JNIEnv so we
2027 // can be here operating on behalf of a suspended thread (4432884).
2028 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2029 JavaThreadState state = thread->thread_state();
2031 // We mark this thread_blocked state as a suspend-equivalent so
2032 // that a caller to is_ext_suspend_completed() won't be confused.
2033 // The suspend-equivalent state is cleared by java_suspend_self().
2034 thread->set_suspend_equivalent();
2036 // If the safepoint code sees the _thread_in_native_trans state, it will
2037 // wait until the thread changes to other thread state. There is no
2038 // guarantee on how soon we can obtain the SR_lock and complete the
2039 // self-suspend request. It would be a bad idea to let safepoint wait for
2040 // too long. Temporarily change the state to _thread_blocked to
2041 // let the VM thread know that this thread is ready for GC. The problem
2042 // of changing thread state is that safepoint could happen just after
2043 // java_suspend_self() returns after being resumed, and VM thread will
2044 // see the _thread_blocked state. We must check for safepoint
2045 // after restoring the state and make sure we won't leave while a safepoint
2046 // is in progress.
2047 thread->set_thread_state(_thread_blocked);
2048 thread->java_suspend_self();
2049 thread->set_thread_state(state);
2050 // Make sure new state is seen by VM thread
2051 if (os::is_MP()) {
2052 if (UseMembar) {
2053 // Force a fence between the write above and read below
2054 OrderAccess::fence();
2055 } else {
2056 // Must use this rather than serialization page in particular on Windows
2057 InterfaceSupport::serialize_memory(thread);
2058 }
2059 }
2060 }
2062 if (SafepointSynchronize::do_call_back()) {
2063 // If we are safepointing, then block the caller which may not be
2064 // the same as the target thread (see above).
2065 SafepointSynchronize::block(curJT);
2066 }
2068 if (thread->is_deopt_suspend()) {
2069 thread->clear_deopt_suspend();
2070 RegisterMap map(thread, false);
2071 frame f = thread->last_frame();
2072 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2073 f = f.sender(&map);
2074 }
2075 if (f.id() == thread->must_deopt_id()) {
2076 thread->clear_must_deopt_id();
2077 // Since we know we're safe to deopt the current state is a safe state
2078 f.deoptimize(thread, true);
2079 } else {
2080 fatal("missed deoptimization!");
2081 }
2082 }
2083 }
2085 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2086 // progress or when _suspend_flags is non-zero.
2087 // Current thread needs to self-suspend if there is a suspend request and/or
2088 // block if a safepoint is in progress.
2089 // Also check for pending async exception (not including unsafe access error).
2090 // Note only the native==>VM/Java barriers can call this function and when
2091 // thread state is _thread_in_native_trans.
2092 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2093 check_safepoint_and_suspend_for_native_trans(thread);
2095 if (thread->has_async_exception()) {
2096 // We are in _thread_in_native_trans state, don't handle unsafe
2097 // access error since that may block.
2098 thread->check_and_handle_async_exceptions(false);
2099 }
2100 }
2102 // We need to guarantee the Threads_lock here, since resumes are not
2103 // allowed during safepoint synchronization
2104 // Can only resume from an external suspension
2105 void JavaThread::java_resume() {
2106 assert_locked_or_safepoint(Threads_lock);
2108 // Sanity check: thread is gone, has started exiting or the thread
2109 // was not externally suspended.
2110 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2111 return;
2112 }
2114 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2116 clear_external_suspend();
2118 if (is_ext_suspended()) {
2119 clear_ext_suspended();
2120 SR_lock()->notify_all();
2121 }
2122 }
2124 void JavaThread::create_stack_guard_pages() {
2125 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2126 address low_addr = stack_base() - stack_size();
2127 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2129 int allocate = os::allocate_stack_guard_pages();
2130 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2132 if (allocate && !os::commit_memory((char *) low_addr, len)) {
2133 warning("Attempt to allocate stack guard pages failed.");
2134 return;
2135 }
2137 if (os::guard_memory((char *) low_addr, len)) {
2138 _stack_guard_state = stack_guard_enabled;
2139 } else {
2140 warning("Attempt to protect stack guard pages failed.");
2141 if (os::uncommit_memory((char *) low_addr, len)) {
2142 warning("Attempt to deallocate stack guard pages failed.");
2143 }
2144 }
2145 }
2147 void JavaThread::remove_stack_guard_pages() {
2148 if (_stack_guard_state == stack_guard_unused) return;
2149 address low_addr = stack_base() - stack_size();
2150 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2152 if (os::allocate_stack_guard_pages()) {
2153 if (os::uncommit_memory((char *) low_addr, len)) {
2154 _stack_guard_state = stack_guard_unused;
2155 } else {
2156 warning("Attempt to deallocate stack guard pages failed.");
2157 }
2158 } else {
2159 if (_stack_guard_state == stack_guard_unused) return;
2160 if (os::unguard_memory((char *) low_addr, len)) {
2161 _stack_guard_state = stack_guard_unused;
2162 } else {
2163 warning("Attempt to unprotect stack guard pages failed.");
2164 }
2165 }
2166 }
2168 void JavaThread::enable_stack_yellow_zone() {
2169 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2170 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2172 // The base notation is from the stacks point of view, growing downward.
2173 // We need to adjust it to work correctly with guard_memory()
2174 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2176 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2177 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2179 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2180 _stack_guard_state = stack_guard_enabled;
2181 } else {
2182 warning("Attempt to guard stack yellow zone failed.");
2183 }
2184 enable_register_stack_guard();
2185 }
2187 void JavaThread::disable_stack_yellow_zone() {
2188 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2189 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2191 // Simply return if called for a thread that does not use guard pages.
2192 if (_stack_guard_state == stack_guard_unused) return;
2194 // The base notation is from the stacks point of view, growing downward.
2195 // We need to adjust it to work correctly with guard_memory()
2196 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2198 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2199 _stack_guard_state = stack_guard_yellow_disabled;
2200 } else {
2201 warning("Attempt to unguard stack yellow zone failed.");
2202 }
2203 disable_register_stack_guard();
2204 }
2206 void JavaThread::enable_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();
2212 guarantee(base < stack_base(),"Error calculating stack red zone");
2213 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2215 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2216 warning("Attempt to guard stack red zone failed.");
2217 }
2218 }
2220 void JavaThread::disable_stack_red_zone() {
2221 // The base notation is from the stacks point of view, growing downward.
2222 // We need to adjust it to work correctly with guard_memory()
2223 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2224 address base = stack_red_zone_base() - stack_red_zone_size();
2225 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2226 warning("Attempt to unguard stack red zone failed.");
2227 }
2228 }
2230 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2231 // ignore is there is no stack
2232 if (!has_last_Java_frame()) return;
2233 // traverse the stack frames. Starts from top frame.
2234 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2235 frame* fr = fst.current();
2236 f(fr, fst.register_map());
2237 }
2238 }
2241 #ifndef PRODUCT
2242 // Deoptimization
2243 // Function for testing deoptimization
2244 void JavaThread::deoptimize() {
2245 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2246 StackFrameStream fst(this, UseBiasedLocking);
2247 bool deopt = false; // Dump stack only if a deopt actually happens.
2248 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2249 // Iterate over all frames in the thread and deoptimize
2250 for(; !fst.is_done(); fst.next()) {
2251 if(fst.current()->can_be_deoptimized()) {
2253 if (only_at) {
2254 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2255 // consists of comma or carriage return separated numbers so
2256 // search for the current bci in that string.
2257 address pc = fst.current()->pc();
2258 nmethod* nm = (nmethod*) fst.current()->cb();
2259 ScopeDesc* sd = nm->scope_desc_at( pc);
2260 char buffer[8];
2261 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2262 size_t len = strlen(buffer);
2263 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2264 while (found != NULL) {
2265 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2266 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2267 // Check that the bci found is bracketed by terminators.
2268 break;
2269 }
2270 found = strstr(found + 1, buffer);
2271 }
2272 if (!found) {
2273 continue;
2274 }
2275 }
2277 if (DebugDeoptimization && !deopt) {
2278 deopt = true; // One-time only print before deopt
2279 tty->print_cr("[BEFORE Deoptimization]");
2280 trace_frames();
2281 trace_stack();
2282 }
2283 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2284 }
2285 }
2287 if (DebugDeoptimization && deopt) {
2288 tty->print_cr("[AFTER Deoptimization]");
2289 trace_frames();
2290 }
2291 }
2294 // Make zombies
2295 void JavaThread::make_zombies() {
2296 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2297 if (fst.current()->can_be_deoptimized()) {
2298 // it is a Java nmethod
2299 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2300 nm->make_not_entrant();
2301 }
2302 }
2303 }
2304 #endif // PRODUCT
2307 void JavaThread::deoptimized_wrt_marked_nmethods() {
2308 if (!has_last_Java_frame()) return;
2309 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2310 StackFrameStream fst(this, UseBiasedLocking);
2311 for(; !fst.is_done(); fst.next()) {
2312 if (fst.current()->should_be_deoptimized()) {
2313 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2314 }
2315 }
2316 }
2319 // GC support
2320 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2322 void JavaThread::gc_epilogue() {
2323 frames_do(frame_gc_epilogue);
2324 }
2327 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2329 void JavaThread::gc_prologue() {
2330 frames_do(frame_gc_prologue);
2331 }
2334 void JavaThread::oops_do(OopClosure* f) {
2335 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2336 // since there may be more than one thread using each ThreadProfiler.
2338 // Traverse the GCHandles
2339 Thread::oops_do(f);
2341 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2342 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2344 if (has_last_Java_frame()) {
2346 // Traverse the privileged stack
2347 if (_privileged_stack_top != NULL) {
2348 _privileged_stack_top->oops_do(f);
2349 }
2351 // traverse the registered growable array
2352 if (_array_for_gc != NULL) {
2353 for (int index = 0; index < _array_for_gc->length(); index++) {
2354 f->do_oop(_array_for_gc->adr_at(index));
2355 }
2356 }
2358 // Traverse the monitor chunks
2359 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2360 chunk->oops_do(f);
2361 }
2363 // Traverse the execution stack
2364 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2365 fst.current()->oops_do(f, fst.register_map());
2366 }
2367 }
2369 // callee_target is never live across a gc point so NULL it here should
2370 // it still contain a methdOop.
2372 set_callee_target(NULL);
2374 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2375 // If we have deferred set_locals there might be oops waiting to be
2376 // written
2377 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2378 if (list != NULL) {
2379 for (int i = 0; i < list->length(); i++) {
2380 list->at(i)->oops_do(f);
2381 }
2382 }
2384 // Traverse instance variables at the end since the GC may be moving things
2385 // around using this function
2386 f->do_oop((oop*) &_threadObj);
2387 f->do_oop((oop*) &_vm_result);
2388 f->do_oop((oop*) &_vm_result_2);
2389 f->do_oop((oop*) &_exception_oop);
2390 f->do_oop((oop*) &_pending_async_exception);
2392 if (jvmti_thread_state() != NULL) {
2393 jvmti_thread_state()->oops_do(f);
2394 }
2395 }
2397 void JavaThread::nmethods_do() {
2398 // Traverse the GCHandles
2399 Thread::nmethods_do();
2401 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2402 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2404 if (has_last_Java_frame()) {
2405 // Traverse the execution stack
2406 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2407 fst.current()->nmethods_do();
2408 }
2409 }
2410 }
2412 // Printing
2413 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2414 switch (_thread_state) {
2415 case _thread_uninitialized: return "_thread_uninitialized";
2416 case _thread_new: return "_thread_new";
2417 case _thread_new_trans: return "_thread_new_trans";
2418 case _thread_in_native: return "_thread_in_native";
2419 case _thread_in_native_trans: return "_thread_in_native_trans";
2420 case _thread_in_vm: return "_thread_in_vm";
2421 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2422 case _thread_in_Java: return "_thread_in_Java";
2423 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2424 case _thread_blocked: return "_thread_blocked";
2425 case _thread_blocked_trans: return "_thread_blocked_trans";
2426 default: return "unknown thread state";
2427 }
2428 }
2430 #ifndef PRODUCT
2431 void JavaThread::print_thread_state_on(outputStream *st) const {
2432 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2433 };
2434 void JavaThread::print_thread_state() const {
2435 print_thread_state_on(tty);
2436 };
2437 #endif // PRODUCT
2439 // Called by Threads::print() for VM_PrintThreads operation
2440 void JavaThread::print_on(outputStream *st) const {
2441 st->print("\"%s\" ", get_thread_name());
2442 oop thread_oop = threadObj();
2443 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2444 Thread::print_on(st);
2445 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2446 st->print_cr("[" INTPTR_FORMAT ".." INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12), highest_lock());
2447 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2448 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2449 }
2450 #ifndef PRODUCT
2451 print_thread_state_on(st);
2452 _safepoint_state->print_on(st);
2453 #endif // PRODUCT
2454 }
2456 // Called by fatal error handler. The difference between this and
2457 // JavaThread::print() is that we can't grab lock or allocate memory.
2458 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2459 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2460 oop thread_obj = threadObj();
2461 if (thread_obj != NULL) {
2462 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2463 }
2464 st->print(" [");
2465 st->print("%s", _get_thread_state_name(_thread_state));
2466 if (osthread()) {
2467 st->print(", id=%d", osthread()->thread_id());
2468 }
2469 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2470 _stack_base - _stack_size, _stack_base);
2471 st->print("]");
2472 return;
2473 }
2475 // Verification
2477 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2479 void JavaThread::verify() {
2480 // Verify oops in the thread.
2481 oops_do(&VerifyOopClosure::verify_oop);
2483 // Verify the stack frames.
2484 frames_do(frame_verify);
2485 }
2487 // CR 6300358 (sub-CR 2137150)
2488 // Most callers of this method assume that it can't return NULL but a
2489 // thread may not have a name whilst it is in the process of attaching to
2490 // the VM - see CR 6412693, and there are places where a JavaThread can be
2491 // seen prior to having it's threadObj set (eg JNI attaching threads and
2492 // if vm exit occurs during initialization). These cases can all be accounted
2493 // for such that this method never returns NULL.
2494 const char* JavaThread::get_thread_name() const {
2495 #ifdef ASSERT
2496 // early safepoints can hit while current thread does not yet have TLS
2497 if (!SafepointSynchronize::is_at_safepoint()) {
2498 Thread *cur = Thread::current();
2499 if (!(cur->is_Java_thread() && cur == this)) {
2500 // Current JavaThreads are allowed to get their own name without
2501 // the Threads_lock.
2502 assert_locked_or_safepoint(Threads_lock);
2503 }
2504 }
2505 #endif // ASSERT
2506 return get_thread_name_string();
2507 }
2509 // Returns a non-NULL representation of this thread's name, or a suitable
2510 // descriptive string if there is no set name
2511 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2512 const char* name_str;
2513 oop thread_obj = threadObj();
2514 if (thread_obj != NULL) {
2515 typeArrayOop name = java_lang_Thread::name(thread_obj);
2516 if (name != NULL) {
2517 if (buf == NULL) {
2518 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2519 }
2520 else {
2521 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2522 }
2523 }
2524 else if (is_attaching()) { // workaround for 6412693 - see 6404306
2525 name_str = "<no-name - thread is attaching>";
2526 }
2527 else {
2528 name_str = Thread::name();
2529 }
2530 }
2531 else {
2532 name_str = Thread::name();
2533 }
2534 assert(name_str != NULL, "unexpected NULL thread name");
2535 return name_str;
2536 }
2539 const char* JavaThread::get_threadgroup_name() const {
2540 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2541 oop thread_obj = threadObj();
2542 if (thread_obj != NULL) {
2543 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2544 if (thread_group != NULL) {
2545 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2546 // ThreadGroup.name can be null
2547 if (name != NULL) {
2548 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2549 return str;
2550 }
2551 }
2552 }
2553 return NULL;
2554 }
2556 const char* JavaThread::get_parent_name() const {
2557 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2558 oop thread_obj = threadObj();
2559 if (thread_obj != NULL) {
2560 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2561 if (thread_group != NULL) {
2562 oop parent = java_lang_ThreadGroup::parent(thread_group);
2563 if (parent != NULL) {
2564 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2565 // ThreadGroup.name can be null
2566 if (name != NULL) {
2567 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2568 return str;
2569 }
2570 }
2571 }
2572 }
2573 return NULL;
2574 }
2576 ThreadPriority JavaThread::java_priority() const {
2577 oop thr_oop = threadObj();
2578 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2579 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2580 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2581 return priority;
2582 }
2584 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2586 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2587 // Link Java Thread object <-> C++ Thread
2589 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2590 // and put it into a new Handle. The Handle "thread_oop" can then
2591 // be used to pass the C++ thread object to other methods.
2593 // Set the Java level thread object (jthread) field of the
2594 // new thread (a JavaThread *) to C++ thread object using the
2595 // "thread_oop" handle.
2597 // Set the thread field (a JavaThread *) of the
2598 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2600 Handle thread_oop(Thread::current(),
2601 JNIHandles::resolve_non_null(jni_thread));
2602 assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
2603 "must be initialized");
2604 set_threadObj(thread_oop());
2605 java_lang_Thread::set_thread(thread_oop(), this);
2607 if (prio == NoPriority) {
2608 prio = java_lang_Thread::priority(thread_oop());
2609 assert(prio != NoPriority, "A valid priority should be present");
2610 }
2612 // Push the Java priority down to the native thread; needs Threads_lock
2613 Thread::set_priority(this, prio);
2615 // Add the new thread to the Threads list and set it in motion.
2616 // We must have threads lock in order to call Threads::add.
2617 // It is crucial that we do not block before the thread is
2618 // added to the Threads list for if a GC happens, then the java_thread oop
2619 // will not be visited by GC.
2620 Threads::add(this);
2621 }
2623 oop JavaThread::current_park_blocker() {
2624 // Support for JSR-166 locks
2625 oop thread_oop = threadObj();
2626 if (thread_oop != NULL &&
2627 JDK_Version::current().supports_thread_park_blocker()) {
2628 return java_lang_Thread::park_blocker(thread_oop);
2629 }
2630 return NULL;
2631 }
2634 void JavaThread::print_stack_on(outputStream* st) {
2635 if (!has_last_Java_frame()) return;
2636 ResourceMark rm;
2637 HandleMark hm;
2639 RegisterMap reg_map(this);
2640 vframe* start_vf = last_java_vframe(®_map);
2641 int count = 0;
2642 for (vframe* f = start_vf; f; f = f->sender() ) {
2643 if (f->is_java_frame()) {
2644 javaVFrame* jvf = javaVFrame::cast(f);
2645 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2647 // Print out lock information
2648 if (JavaMonitorsInStackTrace) {
2649 jvf->print_lock_info_on(st, count);
2650 }
2651 } else {
2652 // Ignore non-Java frames
2653 }
2655 // Bail-out case for too deep stacks
2656 count++;
2657 if (MaxJavaStackTraceDepth == count) return;
2658 }
2659 }
2662 // JVMTI PopFrame support
2663 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2664 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2665 if (in_bytes(size_in_bytes) != 0) {
2666 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes));
2667 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2668 Copy::conjoint_bytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2669 }
2670 }
2672 void* JavaThread::popframe_preserved_args() {
2673 return _popframe_preserved_args;
2674 }
2676 ByteSize JavaThread::popframe_preserved_args_size() {
2677 return in_ByteSize(_popframe_preserved_args_size);
2678 }
2680 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2681 int sz = in_bytes(popframe_preserved_args_size());
2682 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2683 return in_WordSize(sz / wordSize);
2684 }
2686 void JavaThread::popframe_free_preserved_args() {
2687 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2688 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
2689 _popframe_preserved_args = NULL;
2690 _popframe_preserved_args_size = 0;
2691 }
2693 #ifndef PRODUCT
2695 void JavaThread::trace_frames() {
2696 tty->print_cr("[Describe stack]");
2697 int frame_no = 1;
2698 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2699 tty->print(" %d. ", frame_no++);
2700 fst.current()->print_value_on(tty,this);
2701 tty->cr();
2702 }
2703 }
2706 void JavaThread::trace_stack_from(vframe* start_vf) {
2707 ResourceMark rm;
2708 int vframe_no = 1;
2709 for (vframe* f = start_vf; f; f = f->sender() ) {
2710 if (f->is_java_frame()) {
2711 javaVFrame::cast(f)->print_activation(vframe_no++);
2712 } else {
2713 f->print();
2714 }
2715 if (vframe_no > StackPrintLimit) {
2716 tty->print_cr("...<more frames>...");
2717 return;
2718 }
2719 }
2720 }
2723 void JavaThread::trace_stack() {
2724 if (!has_last_Java_frame()) return;
2725 ResourceMark rm;
2726 HandleMark hm;
2727 RegisterMap reg_map(this);
2728 trace_stack_from(last_java_vframe(®_map));
2729 }
2732 #endif // PRODUCT
2735 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2736 assert(reg_map != NULL, "a map must be given");
2737 frame f = last_frame();
2738 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
2739 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2740 }
2741 return NULL;
2742 }
2745 klassOop JavaThread::security_get_caller_class(int depth) {
2746 vframeStream vfst(this);
2747 vfst.security_get_caller_frame(depth);
2748 if (!vfst.at_end()) {
2749 return vfst.method()->method_holder();
2750 }
2751 return NULL;
2752 }
2754 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
2755 assert(thread->is_Compiler_thread(), "must be compiler thread");
2756 CompileBroker::compiler_thread_loop();
2757 }
2759 // Create a CompilerThread
2760 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
2761 : JavaThread(&compiler_thread_entry) {
2762 _env = NULL;
2763 _log = NULL;
2764 _task = NULL;
2765 _queue = queue;
2766 _counters = counters;
2768 #ifndef PRODUCT
2769 _ideal_graph_printer = NULL;
2770 #endif
2771 }
2774 // ======= Threads ========
2776 // The Threads class links together all active threads, and provides
2777 // operations over all threads. It is protected by its own Mutex
2778 // lock, which is also used in other contexts to protect thread
2779 // operations from having the thread being operated on from exiting
2780 // and going away unexpectedly (e.g., safepoint synchronization)
2782 JavaThread* Threads::_thread_list = NULL;
2783 int Threads::_number_of_threads = 0;
2784 int Threads::_number_of_non_daemon_threads = 0;
2785 int Threads::_return_code = 0;
2786 size_t JavaThread::_stack_size_at_create = 0;
2788 // All JavaThreads
2789 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
2791 void os_stream();
2793 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
2794 void Threads::threads_do(ThreadClosure* tc) {
2795 assert_locked_or_safepoint(Threads_lock);
2796 // ALL_JAVA_THREADS iterates through all JavaThreads
2797 ALL_JAVA_THREADS(p) {
2798 tc->do_thread(p);
2799 }
2800 // Someday we could have a table or list of all non-JavaThreads.
2801 // For now, just manually iterate through them.
2802 tc->do_thread(VMThread::vm_thread());
2803 Universe::heap()->gc_threads_do(tc);
2804 WatcherThread *wt = WatcherThread::watcher_thread();
2805 // Strictly speaking, the following NULL check isn't sufficient to make sure
2806 // the data for WatcherThread is still valid upon being examined. However,
2807 // considering that WatchThread terminates when the VM is on the way to
2808 // exit at safepoint, the chance of the above is extremely small. The right
2809 // way to prevent termination of WatcherThread would be to acquire
2810 // Terminator_lock, but we can't do that without violating the lock rank
2811 // checking in some cases.
2812 if (wt != NULL)
2813 tc->do_thread(wt);
2815 // If CompilerThreads ever become non-JavaThreads, add them here
2816 }
2818 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
2820 extern void JDK_Version_init();
2822 // Check version
2823 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
2825 // Initialize the output stream module
2826 ostream_init();
2828 // Process java launcher properties.
2829 Arguments::process_sun_java_launcher_properties(args);
2831 // Initialize the os module before using TLS
2832 os::init();
2834 // Initialize system properties.
2835 Arguments::init_system_properties();
2837 // So that JDK version can be used as a discrimintor when parsing arguments
2838 JDK_Version_init();
2840 // Parse arguments
2841 jint parse_result = Arguments::parse(args);
2842 if (parse_result != JNI_OK) return parse_result;
2844 if (PauseAtStartup) {
2845 os::pause();
2846 }
2848 HS_DTRACE_PROBE(hotspot, vm__init__begin);
2850 // Record VM creation timing statistics
2851 TraceVmCreationTime create_vm_timer;
2852 create_vm_timer.start();
2854 // Timing (must come after argument parsing)
2855 TraceTime timer("Create VM", TraceStartupTime);
2857 // Initialize the os module after parsing the args
2858 jint os_init_2_result = os::init_2();
2859 if (os_init_2_result != JNI_OK) return os_init_2_result;
2861 // Initialize output stream logging
2862 ostream_init_log();
2864 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
2865 // Must be before create_vm_init_agents()
2866 if (Arguments::init_libraries_at_startup()) {
2867 convert_vm_init_libraries_to_agents();
2868 }
2870 // Launch -agentlib/-agentpath and converted -Xrun agents
2871 if (Arguments::init_agents_at_startup()) {
2872 create_vm_init_agents();
2873 }
2875 // Initialize Threads state
2876 _thread_list = NULL;
2877 _number_of_threads = 0;
2878 _number_of_non_daemon_threads = 0;
2880 // Initialize TLS
2881 ThreadLocalStorage::init();
2883 // Initialize global data structures and create system classes in heap
2884 vm_init_globals();
2886 // Attach the main thread to this os thread
2887 JavaThread* main_thread = new JavaThread();
2888 main_thread->set_thread_state(_thread_in_vm);
2889 // must do this before set_active_handles and initialize_thread_local_storage
2890 // Note: on solaris initialize_thread_local_storage() will (indirectly)
2891 // change the stack size recorded here to one based on the java thread
2892 // stacksize. This adjusted size is what is used to figure the placement
2893 // of the guard pages.
2894 main_thread->record_stack_base_and_size();
2895 main_thread->initialize_thread_local_storage();
2897 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
2899 if (!main_thread->set_as_starting_thread()) {
2900 vm_shutdown_during_initialization(
2901 "Failed necessary internal allocation. Out of swap space");
2902 delete main_thread;
2903 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2904 return JNI_ENOMEM;
2905 }
2907 // Enable guard page *after* os::create_main_thread(), otherwise it would
2908 // crash Linux VM, see notes in os_linux.cpp.
2909 main_thread->create_stack_guard_pages();
2911 // Initialize Java-Leve synchronization subsystem
2912 ObjectSynchronizer::Initialize() ;
2914 // Initialize global modules
2915 jint status = init_globals();
2916 if (status != JNI_OK) {
2917 delete main_thread;
2918 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2919 return status;
2920 }
2922 HandleMark hm;
2924 { MutexLocker mu(Threads_lock);
2925 Threads::add(main_thread);
2926 }
2928 // Any JVMTI raw monitors entered in onload will transition into
2929 // real raw monitor. VM is setup enough here for raw monitor enter.
2930 JvmtiExport::transition_pending_onload_raw_monitors();
2932 if (VerifyBeforeGC &&
2933 Universe::heap()->total_collections() >= VerifyGCStartAt) {
2934 Universe::heap()->prepare_for_verify();
2935 Universe::verify(); // make sure we're starting with a clean slate
2936 }
2938 // Create the VMThread
2939 { TraceTime timer("Start VMThread", TraceStartupTime);
2940 VMThread::create();
2941 Thread* vmthread = VMThread::vm_thread();
2943 if (!os::create_thread(vmthread, os::vm_thread))
2944 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
2946 // Wait for the VM thread to become ready, and VMThread::run to initialize
2947 // Monitors can have spurious returns, must always check another state flag
2948 {
2949 MutexLocker ml(Notify_lock);
2950 os::start_thread(vmthread);
2951 while (vmthread->active_handles() == NULL) {
2952 Notify_lock->wait();
2953 }
2954 }
2955 }
2957 assert (Universe::is_fully_initialized(), "not initialized");
2958 EXCEPTION_MARK;
2960 // At this point, the Universe is initialized, but we have not executed
2961 // any byte code. Now is a good time (the only time) to dump out the
2962 // internal state of the JVM for sharing.
2964 if (DumpSharedSpaces) {
2965 Universe::heap()->preload_and_dump(CHECK_0);
2966 ShouldNotReachHere();
2967 }
2969 // Always call even when there are not JVMTI environments yet, since environments
2970 // may be attached late and JVMTI must track phases of VM execution
2971 JvmtiExport::enter_start_phase();
2973 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
2974 JvmtiExport::post_vm_start();
2976 {
2977 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
2979 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
2980 create_vm_init_libraries();
2981 }
2983 if (InitializeJavaLangString) {
2984 initialize_class(vmSymbolHandles::java_lang_String(), CHECK_0);
2985 } else {
2986 warning("java.lang.String not initialized");
2987 }
2989 if (AggressiveOpts) {
2990 {
2991 // Forcibly initialize java/util/HashMap and mutate the private
2992 // static final "frontCacheEnabled" field before we start creating instances
2993 #ifdef ASSERT
2994 klassOop tmp_k = SystemDictionary::find(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0);
2995 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
2996 #endif
2997 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0);
2998 KlassHandle k = KlassHandle(THREAD, k_o);
2999 guarantee(k.not_null(), "Must find java/util/HashMap");
3000 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3001 ik->initialize(CHECK_0);
3002 fieldDescriptor fd;
3003 // Possible we might not find this field; if so, don't break
3004 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3005 k()->bool_field_put(fd.offset(), true);
3006 }
3007 }
3009 if (UseStringCache) {
3010 // Forcibly initialize java/lang/StringValue and mutate the private
3011 // static final "stringCacheEnabled" field before we start creating instances
3012 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3013 // Possible that StringValue isn't present: if so, silently don't break
3014 if (k_o != NULL) {
3015 KlassHandle k = KlassHandle(THREAD, k_o);
3016 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3017 ik->initialize(CHECK_0);
3018 fieldDescriptor fd;
3019 // Possible we might not find this field: if so, silently don't break
3020 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3021 k()->bool_field_put(fd.offset(), true);
3022 }
3023 }
3024 }
3025 }
3027 // Initialize java_lang.System (needed before creating the thread)
3028 if (InitializeJavaLangSystem) {
3029 initialize_class(vmSymbolHandles::java_lang_System(), CHECK_0);
3030 initialize_class(vmSymbolHandles::java_lang_ThreadGroup(), CHECK_0);
3031 Handle thread_group = create_initial_thread_group(CHECK_0);
3032 Universe::set_main_thread_group(thread_group());
3033 initialize_class(vmSymbolHandles::java_lang_Thread(), CHECK_0);
3034 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3035 main_thread->set_threadObj(thread_object);
3036 // Set thread status to running since main thread has
3037 // been started and running.
3038 java_lang_Thread::set_thread_status(thread_object,
3039 java_lang_Thread::RUNNABLE);
3041 // The VM preresolve methods to these classes. Make sure that get initialized
3042 initialize_class(vmSymbolHandles::java_lang_reflect_Method(), CHECK_0);
3043 initialize_class(vmSymbolHandles::java_lang_ref_Finalizer(), CHECK_0);
3044 // The VM creates & returns objects of this class. Make sure it's initialized.
3045 initialize_class(vmSymbolHandles::java_lang_Class(), CHECK_0);
3046 call_initializeSystemClass(CHECK_0);
3047 } else {
3048 warning("java.lang.System not initialized");
3049 }
3051 // an instance of OutOfMemory exception has been allocated earlier
3052 if (InitializeJavaLangExceptionsErrors) {
3053 initialize_class(vmSymbolHandles::java_lang_OutOfMemoryError(), CHECK_0);
3054 initialize_class(vmSymbolHandles::java_lang_NullPointerException(), CHECK_0);
3055 initialize_class(vmSymbolHandles::java_lang_ClassCastException(), CHECK_0);
3056 initialize_class(vmSymbolHandles::java_lang_ArrayStoreException(), CHECK_0);
3057 initialize_class(vmSymbolHandles::java_lang_ArithmeticException(), CHECK_0);
3058 initialize_class(vmSymbolHandles::java_lang_StackOverflowError(), CHECK_0);
3059 initialize_class(vmSymbolHandles::java_lang_IllegalMonitorStateException(), CHECK_0);
3060 } else {
3061 warning("java.lang.OutOfMemoryError has not been initialized");
3062 warning("java.lang.NullPointerException has not been initialized");
3063 warning("java.lang.ClassCastException has not been initialized");
3064 warning("java.lang.ArrayStoreException has not been initialized");
3065 warning("java.lang.ArithmeticException has not been initialized");
3066 warning("java.lang.StackOverflowError has not been initialized");
3067 }
3068 }
3070 // See : bugid 4211085.
3071 // Background : the static initializer of java.lang.Compiler tries to read
3072 // property"java.compiler" and read & write property "java.vm.info".
3073 // When a security manager is installed through the command line
3074 // option "-Djava.security.manager", the above properties are not
3075 // readable and the static initializer for java.lang.Compiler fails
3076 // resulting in a NoClassDefFoundError. This can happen in any
3077 // user code which calls methods in java.lang.Compiler.
3078 // Hack : the hack is to pre-load and initialize this class, so that only
3079 // system domains are on the stack when the properties are read.
3080 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3081 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3082 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3083 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3084 // Once that is done, we should remove this hack.
3085 initialize_class(vmSymbolHandles::java_lang_Compiler(), CHECK_0);
3087 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3088 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3089 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3090 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3091 // This should also be taken out as soon as 4211383 gets fixed.
3092 reset_vm_info_property(CHECK_0);
3094 quicken_jni_functions();
3096 // Set flag that basic initialization has completed. Used by exceptions and various
3097 // debug stuff, that does not work until all basic classes have been initialized.
3098 set_init_completed();
3100 HS_DTRACE_PROBE(hotspot, vm__init__end);
3102 // record VM initialization completion time
3103 Management::record_vm_init_completed();
3105 // Compute system loader. Note that this has to occur after set_init_completed, since
3106 // valid exceptions may be thrown in the process.
3107 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3108 // set_init_completed has just been called, causing exceptions not to be shortcut
3109 // anymore. We call vm_exit_during_initialization directly instead.
3110 SystemDictionary::compute_java_system_loader(THREAD);
3111 if (HAS_PENDING_EXCEPTION) {
3112 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3113 }
3115 #ifndef SERIALGC
3116 // Support for ConcurrentMarkSweep. This should be cleaned up
3117 // and better encapsulated. The ugly nested if test would go away
3118 // once things are properly refactored. XXX YSR
3119 if (UseConcMarkSweepGC || UseG1GC) {
3120 if (UseConcMarkSweepGC) {
3121 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3122 } else {
3123 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3124 }
3125 if (HAS_PENDING_EXCEPTION) {
3126 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3127 }
3128 }
3129 #endif // SERIALGC
3131 // Always call even when there are not JVMTI environments yet, since environments
3132 // may be attached late and JVMTI must track phases of VM execution
3133 JvmtiExport::enter_live_phase();
3135 // Signal Dispatcher needs to be started before VMInit event is posted
3136 os::signal_init();
3138 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3139 if (!DisableAttachMechanism) {
3140 if (StartAttachListener || AttachListener::init_at_startup()) {
3141 AttachListener::init();
3142 }
3143 }
3145 // Launch -Xrun agents
3146 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3147 // back-end can launch with -Xdebug -Xrunjdwp.
3148 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3149 create_vm_init_libraries();
3150 }
3152 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3153 JvmtiExport::post_vm_initialized();
3155 Chunk::start_chunk_pool_cleaner_task();
3157 // initialize compiler(s)
3158 CompileBroker::compilation_init();
3160 Management::initialize(THREAD);
3161 if (HAS_PENDING_EXCEPTION) {
3162 // management agent fails to start possibly due to
3163 // configuration problem and is responsible for printing
3164 // stack trace if appropriate. Simply exit VM.
3165 vm_exit(1);
3166 }
3168 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3169 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3170 if (MemProfiling) MemProfiler::engage();
3171 StatSampler::engage();
3172 if (CheckJNICalls) JniPeriodicChecker::engage();
3174 BiasedLocking::init();
3177 // Start up the WatcherThread if there are any periodic tasks
3178 // NOTE: All PeriodicTasks should be registered by now. If they
3179 // aren't, late joiners might appear to start slowly (we might
3180 // take a while to process their first tick).
3181 if (PeriodicTask::num_tasks() > 0) {
3182 WatcherThread::start();
3183 }
3185 create_vm_timer.end();
3186 return JNI_OK;
3187 }
3189 // type for the Agent_OnLoad and JVM_OnLoad entry points
3190 extern "C" {
3191 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3192 }
3193 // Find a command line agent library and return its entry point for
3194 // -agentlib: -agentpath: -Xrun
3195 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3196 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3197 OnLoadEntry_t on_load_entry = NULL;
3198 void *library = agent->os_lib(); // check if we have looked it up before
3200 if (library == NULL) {
3201 char buffer[JVM_MAXPATHLEN];
3202 char ebuf[1024];
3203 const char *name = agent->name();
3205 if (agent->is_absolute_path()) {
3206 library = hpi::dll_load(name, ebuf, sizeof ebuf);
3207 if (library == NULL) {
3208 // If we can't find the agent, exit.
3209 vm_exit_during_initialization("Could not find agent library in absolute path", name);
3210 }
3211 } else {
3212 // Try to load the agent from the standard dll directory
3213 hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
3214 library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3215 #ifdef KERNEL
3216 // Download instrument dll
3217 if (library == NULL && strcmp(name, "instrument") == 0) {
3218 char *props = Arguments::get_kernel_properties();
3219 char *home = Arguments::get_java_home();
3220 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false"
3221 " sun.jkernel.DownloadManager -download client_jvm";
3222 int length = strlen(props) + strlen(home) + strlen(fmt) + 1;
3223 char *cmd = AllocateHeap(length);
3224 jio_snprintf(cmd, length, fmt, home, props);
3225 int status = os::fork_and_exec(cmd);
3226 FreeHeap(props);
3227 FreeHeap(cmd);
3228 if (status == -1) {
3229 warning(cmd);
3230 vm_exit_during_initialization("fork_and_exec failed: %s",
3231 strerror(errno));
3232 }
3233 // when this comes back the instrument.dll should be where it belongs.
3234 library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3235 }
3236 #endif // KERNEL
3237 if (library == NULL) { // Try the local directory
3238 char ns[1] = {0};
3239 hpi::dll_build_name(buffer, sizeof(buffer), ns, name);
3240 library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3241 if (library == NULL) {
3242 // If we can't find the agent, exit.
3243 vm_exit_during_initialization("Could not find agent library on the library path or in the local directory", name);
3244 }
3245 }
3246 }
3247 agent->set_os_lib(library);
3248 }
3250 // Find the OnLoad function.
3251 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3252 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, hpi::dll_lookup(library, on_load_symbols[symbol_index]));
3253 if (on_load_entry != NULL) break;
3254 }
3255 return on_load_entry;
3256 }
3258 // Find the JVM_OnLoad entry point
3259 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3260 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3261 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3262 }
3264 // Find the Agent_OnLoad entry point
3265 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3266 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3267 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3268 }
3270 // For backwards compatibility with -Xrun
3271 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3272 // treated like -agentpath:
3273 // Must be called before agent libraries are created
3274 void Threads::convert_vm_init_libraries_to_agents() {
3275 AgentLibrary* agent;
3276 AgentLibrary* next;
3278 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3279 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3280 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3282 // If there is an JVM_OnLoad function it will get called later,
3283 // otherwise see if there is an Agent_OnLoad
3284 if (on_load_entry == NULL) {
3285 on_load_entry = lookup_agent_on_load(agent);
3286 if (on_load_entry != NULL) {
3287 // switch it to the agent list -- so that Agent_OnLoad will be called,
3288 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3289 Arguments::convert_library_to_agent(agent);
3290 } else {
3291 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3292 }
3293 }
3294 }
3295 }
3297 // Create agents for -agentlib: -agentpath: and converted -Xrun
3298 // Invokes Agent_OnLoad
3299 // Called very early -- before JavaThreads exist
3300 void Threads::create_vm_init_agents() {
3301 extern struct JavaVM_ main_vm;
3302 AgentLibrary* agent;
3304 JvmtiExport::enter_onload_phase();
3305 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3306 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3308 if (on_load_entry != NULL) {
3309 // Invoke the Agent_OnLoad function
3310 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3311 if (err != JNI_OK) {
3312 vm_exit_during_initialization("agent library failed to init", agent->name());
3313 }
3314 } else {
3315 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3316 }
3317 }
3318 JvmtiExport::enter_primordial_phase();
3319 }
3321 extern "C" {
3322 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3323 }
3325 void Threads::shutdown_vm_agents() {
3326 // Send any Agent_OnUnload notifications
3327 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3328 extern struct JavaVM_ main_vm;
3329 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3331 // Find the Agent_OnUnload function.
3332 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3333 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3334 hpi::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3336 // Invoke the Agent_OnUnload function
3337 if (unload_entry != NULL) {
3338 JavaThread* thread = JavaThread::current();
3339 ThreadToNativeFromVM ttn(thread);
3340 HandleMark hm(thread);
3341 (*unload_entry)(&main_vm);
3342 break;
3343 }
3344 }
3345 }
3346 }
3348 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3349 // Invokes JVM_OnLoad
3350 void Threads::create_vm_init_libraries() {
3351 extern struct JavaVM_ main_vm;
3352 AgentLibrary* agent;
3354 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3355 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3357 if (on_load_entry != NULL) {
3358 // Invoke the JVM_OnLoad function
3359 JavaThread* thread = JavaThread::current();
3360 ThreadToNativeFromVM ttn(thread);
3361 HandleMark hm(thread);
3362 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3363 if (err != JNI_OK) {
3364 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3365 }
3366 } else {
3367 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3368 }
3369 }
3370 }
3372 // Last thread running calls java.lang.Shutdown.shutdown()
3373 void JavaThread::invoke_shutdown_hooks() {
3374 HandleMark hm(this);
3376 // We could get here with a pending exception, if so clear it now.
3377 if (this->has_pending_exception()) {
3378 this->clear_pending_exception();
3379 }
3381 EXCEPTION_MARK;
3382 klassOop k =
3383 SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_Shutdown(),
3384 THREAD);
3385 if (k != NULL) {
3386 // SystemDictionary::resolve_or_null will return null if there was
3387 // an exception. If we cannot load the Shutdown class, just don't
3388 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3389 // and finalizers (if runFinalizersOnExit is set) won't be run.
3390 // Note that if a shutdown hook was registered or runFinalizersOnExit
3391 // was called, the Shutdown class would have already been loaded
3392 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3393 instanceKlassHandle shutdown_klass (THREAD, k);
3394 JavaValue result(T_VOID);
3395 JavaCalls::call_static(&result,
3396 shutdown_klass,
3397 vmSymbolHandles::shutdown_method_name(),
3398 vmSymbolHandles::void_method_signature(),
3399 THREAD);
3400 }
3401 CLEAR_PENDING_EXCEPTION;
3402 }
3404 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3405 // the program falls off the end of main(). Another VM exit path is through
3406 // vm_exit() when the program calls System.exit() to return a value or when
3407 // there is a serious error in VM. The two shutdown paths are not exactly
3408 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3409 // and VM_Exit op at VM level.
3410 //
3411 // Shutdown sequence:
3412 // + Wait until we are the last non-daemon thread to execute
3413 // <-- every thing is still working at this moment -->
3414 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3415 // shutdown hooks, run finalizers if finalization-on-exit
3416 // + Call before_exit(), prepare for VM exit
3417 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3418 // currently the only user of this mechanism is File.deleteOnExit())
3419 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3420 // post thread end and vm death events to JVMTI,
3421 // stop signal thread
3422 // + Call JavaThread::exit(), it will:
3423 // > release JNI handle blocks, remove stack guard pages
3424 // > remove this thread from Threads list
3425 // <-- no more Java code from this thread after this point -->
3426 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3427 // the compiler threads at safepoint
3428 // <-- do not use anything that could get blocked by Safepoint -->
3429 // + Disable tracing at JNI/JVM barriers
3430 // + Set _vm_exited flag for threads that are still running native code
3431 // + Delete this thread
3432 // + Call exit_globals()
3433 // > deletes tty
3434 // > deletes PerfMemory resources
3435 // + Return to caller
3437 bool Threads::destroy_vm() {
3438 JavaThread* thread = JavaThread::current();
3440 // Wait until we are the last non-daemon thread to execute
3441 { MutexLocker nu(Threads_lock);
3442 while (Threads::number_of_non_daemon_threads() > 1 )
3443 // This wait should make safepoint checks, wait without a timeout,
3444 // and wait as a suspend-equivalent condition.
3445 //
3446 // Note: If the FlatProfiler is running and this thread is waiting
3447 // for another non-daemon thread to finish, then the FlatProfiler
3448 // is waiting for the external suspend request on this thread to
3449 // complete. wait_for_ext_suspend_completion() will eventually
3450 // timeout, but that takes time. Making this wait a suspend-
3451 // equivalent condition solves that timeout problem.
3452 //
3453 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3454 Mutex::_as_suspend_equivalent_flag);
3455 }
3457 // Hang forever on exit if we are reporting an error.
3458 if (ShowMessageBoxOnError && is_error_reported()) {
3459 os::infinite_sleep();
3460 }
3462 if (JDK_Version::is_jdk12x_version()) {
3463 // We are the last thread running, so check if finalizers should be run.
3464 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3465 HandleMark rm(thread);
3466 Universe::run_finalizers_on_exit();
3467 } else {
3468 // run Java level shutdown hooks
3469 thread->invoke_shutdown_hooks();
3470 }
3472 before_exit(thread);
3474 thread->exit(true);
3476 // Stop VM thread.
3477 {
3478 // 4945125 The vm thread comes to a safepoint during exit.
3479 // GC vm_operations can get caught at the safepoint, and the
3480 // heap is unparseable if they are caught. Grab the Heap_lock
3481 // to prevent this. The GC vm_operations will not be able to
3482 // queue until after the vm thread is dead.
3483 MutexLocker ml(Heap_lock);
3485 VMThread::wait_for_vm_thread_exit();
3486 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3487 VMThread::destroy();
3488 }
3490 // clean up ideal graph printers
3491 #if defined(COMPILER2) && !defined(PRODUCT)
3492 IdealGraphPrinter::clean_up();
3493 #endif
3495 // Now, all Java threads are gone except daemon threads. Daemon threads
3496 // running Java code or in VM are stopped by the Safepoint. However,
3497 // daemon threads executing native code are still running. But they
3498 // will be stopped at native=>Java/VM barriers. Note that we can't
3499 // simply kill or suspend them, as it is inherently deadlock-prone.
3501 #ifndef PRODUCT
3502 // disable function tracing at JNI/JVM barriers
3503 TraceHPI = false;
3504 TraceJNICalls = false;
3505 TraceJVMCalls = false;
3506 TraceRuntimeCalls = false;
3507 #endif
3509 VM_Exit::set_vm_exited();
3511 notify_vm_shutdown();
3513 delete thread;
3515 // exit_globals() will delete tty
3516 exit_globals();
3518 return true;
3519 }
3522 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3523 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3524 return is_supported_jni_version(version);
3525 }
3528 jboolean Threads::is_supported_jni_version(jint version) {
3529 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3530 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3531 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3532 return JNI_FALSE;
3533 }
3536 void Threads::add(JavaThread* p, bool force_daemon) {
3537 // The threads lock must be owned at this point
3538 assert_locked_or_safepoint(Threads_lock);
3539 p->set_next(_thread_list);
3540 _thread_list = p;
3541 _number_of_threads++;
3542 oop threadObj = p->threadObj();
3543 bool daemon = true;
3544 // Bootstrapping problem: threadObj can be null for initial
3545 // JavaThread (or for threads attached via JNI)
3546 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3547 _number_of_non_daemon_threads++;
3548 daemon = false;
3549 }
3551 ThreadService::add_thread(p, daemon);
3553 // Possible GC point.
3554 Events::log("Thread added: " INTPTR_FORMAT, p);
3555 }
3557 void Threads::remove(JavaThread* p) {
3558 // Extra scope needed for Thread_lock, so we can check
3559 // that we do not remove thread without safepoint code notice
3560 { MutexLocker ml(Threads_lock);
3562 assert(includes(p), "p must be present");
3564 JavaThread* current = _thread_list;
3565 JavaThread* prev = NULL;
3567 while (current != p) {
3568 prev = current;
3569 current = current->next();
3570 }
3572 if (prev) {
3573 prev->set_next(current->next());
3574 } else {
3575 _thread_list = p->next();
3576 }
3577 _number_of_threads--;
3578 oop threadObj = p->threadObj();
3579 bool daemon = true;
3580 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
3581 _number_of_non_daemon_threads--;
3582 daemon = false;
3584 // Only one thread left, do a notify on the Threads_lock so a thread waiting
3585 // on destroy_vm will wake up.
3586 if (number_of_non_daemon_threads() == 1)
3587 Threads_lock->notify_all();
3588 }
3589 ThreadService::remove_thread(p, daemon);
3591 // Make sure that safepoint code disregard this thread. This is needed since
3592 // the thread might mess around with locks after this point. This can cause it
3593 // to do callbacks into the safepoint code. However, the safepoint code is not aware
3594 // of this thread since it is removed from the queue.
3595 p->set_terminated_value();
3596 } // unlock Threads_lock
3598 // Since Events::log uses a lock, we grab it outside the Threads_lock
3599 Events::log("Thread exited: " INTPTR_FORMAT, p);
3600 }
3602 // Threads_lock must be held when this is called (or must be called during a safepoint)
3603 bool Threads::includes(JavaThread* p) {
3604 assert(Threads_lock->is_locked(), "sanity check");
3605 ALL_JAVA_THREADS(q) {
3606 if (q == p ) {
3607 return true;
3608 }
3609 }
3610 return false;
3611 }
3613 // Operations on the Threads list for GC. These are not explicitly locked,
3614 // but the garbage collector must provide a safe context for them to run.
3615 // In particular, these things should never be called when the Threads_lock
3616 // is held by some other thread. (Note: the Safepoint abstraction also
3617 // uses the Threads_lock to gurantee this property. It also makes sure that
3618 // all threads gets blocked when exiting or starting).
3620 void Threads::oops_do(OopClosure* f) {
3621 ALL_JAVA_THREADS(p) {
3622 p->oops_do(f);
3623 }
3624 VMThread::vm_thread()->oops_do(f);
3625 }
3627 void Threads::possibly_parallel_oops_do(OopClosure* f) {
3628 // Introduce a mechanism allowing parallel threads to claim threads as
3629 // root groups. Overhead should be small enough to use all the time,
3630 // even in sequential code.
3631 SharedHeap* sh = SharedHeap::heap();
3632 bool is_par = (sh->n_par_threads() > 0);
3633 int cp = SharedHeap::heap()->strong_roots_parity();
3634 ALL_JAVA_THREADS(p) {
3635 if (p->claim_oops_do(is_par, cp)) {
3636 p->oops_do(f);
3637 }
3638 }
3639 VMThread* vmt = VMThread::vm_thread();
3640 if (vmt->claim_oops_do(is_par, cp))
3641 vmt->oops_do(f);
3642 }
3644 #ifndef SERIALGC
3645 // Used by ParallelScavenge
3646 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
3647 ALL_JAVA_THREADS(p) {
3648 q->enqueue(new ThreadRootsTask(p));
3649 }
3650 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
3651 }
3653 // Used by Parallel Old
3654 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
3655 ALL_JAVA_THREADS(p) {
3656 q->enqueue(new ThreadRootsMarkingTask(p));
3657 }
3658 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
3659 }
3660 #endif // SERIALGC
3662 void Threads::nmethods_do() {
3663 ALL_JAVA_THREADS(p) {
3664 p->nmethods_do();
3665 }
3666 VMThread::vm_thread()->nmethods_do();
3667 }
3669 void Threads::gc_epilogue() {
3670 ALL_JAVA_THREADS(p) {
3671 p->gc_epilogue();
3672 }
3673 }
3675 void Threads::gc_prologue() {
3676 ALL_JAVA_THREADS(p) {
3677 p->gc_prologue();
3678 }
3679 }
3681 void Threads::deoptimized_wrt_marked_nmethods() {
3682 ALL_JAVA_THREADS(p) {
3683 p->deoptimized_wrt_marked_nmethods();
3684 }
3685 }
3688 // Get count Java threads that are waiting to enter the specified monitor.
3689 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
3690 address monitor, bool doLock) {
3691 assert(doLock || SafepointSynchronize::is_at_safepoint(),
3692 "must grab Threads_lock or be at safepoint");
3693 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3695 int i = 0;
3696 {
3697 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3698 ALL_JAVA_THREADS(p) {
3699 if (p->is_Compiler_thread()) continue;
3701 address pending = (address)p->current_pending_monitor();
3702 if (pending == monitor) { // found a match
3703 if (i < count) result->append(p); // save the first count matches
3704 i++;
3705 }
3706 }
3707 }
3708 return result;
3709 }
3712 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
3713 assert(doLock ||
3714 Threads_lock->owned_by_self() ||
3715 SafepointSynchronize::is_at_safepoint(),
3716 "must grab Threads_lock or be at safepoint");
3718 // NULL owner means not locked so we can skip the search
3719 if (owner == NULL) return NULL;
3721 {
3722 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3723 ALL_JAVA_THREADS(p) {
3724 // first, see if owner is the address of a Java thread
3725 if (owner == (address)p) return p;
3726 }
3727 }
3728 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
3729 if (UseHeavyMonitors) return NULL;
3731 //
3732 // If we didn't find a matching Java thread and we didn't force use of
3733 // heavyweight monitors, then the owner is the stack address of the
3734 // Lock Word in the owning Java thread's stack.
3735 //
3736 // We can't use Thread::is_lock_owned() or Thread::lock_is_in_stack() because
3737 // those routines rely on the "current" stack pointer. That would be our
3738 // stack pointer which is not relevant to the question. Instead we use the
3739 // highest lock ever entered by the thread and find the thread that is
3740 // higher than and closest to our target stack address.
3741 //
3742 address least_diff = 0;
3743 bool least_diff_initialized = false;
3744 JavaThread* the_owner = NULL;
3745 {
3746 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3747 ALL_JAVA_THREADS(q) {
3748 address addr = q->highest_lock();
3749 if (addr == NULL || addr < owner) continue; // thread has entered no monitors or is too low
3750 address diff = (address)(addr - owner);
3751 if (!least_diff_initialized || diff < least_diff) {
3752 least_diff_initialized = true;
3753 least_diff = diff;
3754 the_owner = q;
3755 }
3756 }
3757 }
3758 assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
3759 return the_owner;
3760 }
3762 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
3763 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
3764 char buf[32];
3765 st->print_cr(os::local_time_string(buf, sizeof(buf)));
3767 st->print_cr("Full thread dump %s (%s %s):",
3768 Abstract_VM_Version::vm_name(),
3769 Abstract_VM_Version::vm_release(),
3770 Abstract_VM_Version::vm_info_string()
3771 );
3772 st->cr();
3774 #ifndef SERIALGC
3775 // Dump concurrent locks
3776 ConcurrentLocksDump concurrent_locks;
3777 if (print_concurrent_locks) {
3778 concurrent_locks.dump_at_safepoint();
3779 }
3780 #endif // SERIALGC
3782 ALL_JAVA_THREADS(p) {
3783 ResourceMark rm;
3784 p->print_on(st);
3785 if (print_stacks) {
3786 if (internal_format) {
3787 p->trace_stack();
3788 } else {
3789 p->print_stack_on(st);
3790 }
3791 }
3792 st->cr();
3793 #ifndef SERIALGC
3794 if (print_concurrent_locks) {
3795 concurrent_locks.print_locks_on(p, st);
3796 }
3797 #endif // SERIALGC
3798 }
3800 VMThread::vm_thread()->print_on(st);
3801 st->cr();
3802 Universe::heap()->print_gc_threads_on(st);
3803 WatcherThread* wt = WatcherThread::watcher_thread();
3804 if (wt != NULL) wt->print_on(st);
3805 st->cr();
3806 CompileBroker::print_compiler_threads_on(st);
3807 st->flush();
3808 }
3810 // Threads::print_on_error() is called by fatal error handler. It's possible
3811 // that VM is not at safepoint and/or current thread is inside signal handler.
3812 // Don't print stack trace, as the stack may not be walkable. Don't allocate
3813 // memory (even in resource area), it might deadlock the error handler.
3814 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
3815 bool found_current = false;
3816 st->print_cr("Java Threads: ( => current thread )");
3817 ALL_JAVA_THREADS(thread) {
3818 bool is_current = (current == thread);
3819 found_current = found_current || is_current;
3821 st->print("%s", is_current ? "=>" : " ");
3823 st->print(PTR_FORMAT, thread);
3824 st->print(" ");
3825 thread->print_on_error(st, buf, buflen);
3826 st->cr();
3827 }
3828 st->cr();
3830 st->print_cr("Other Threads:");
3831 if (VMThread::vm_thread()) {
3832 bool is_current = (current == VMThread::vm_thread());
3833 found_current = found_current || is_current;
3834 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
3836 st->print(PTR_FORMAT, VMThread::vm_thread());
3837 st->print(" ");
3838 VMThread::vm_thread()->print_on_error(st, buf, buflen);
3839 st->cr();
3840 }
3841 WatcherThread* wt = WatcherThread::watcher_thread();
3842 if (wt != NULL) {
3843 bool is_current = (current == wt);
3844 found_current = found_current || is_current;
3845 st->print("%s", is_current ? "=>" : " ");
3847 st->print(PTR_FORMAT, wt);
3848 st->print(" ");
3849 wt->print_on_error(st, buf, buflen);
3850 st->cr();
3851 }
3852 if (!found_current) {
3853 st->cr();
3854 st->print("=>" PTR_FORMAT " (exited) ", current);
3855 current->print_on_error(st, buf, buflen);
3856 st->cr();
3857 }
3858 }
3861 // Lifecycle management for TSM ParkEvents.
3862 // ParkEvents are type-stable (TSM).
3863 // In our particular implementation they happen to be immortal.
3864 //
3865 // We manage concurrency on the FreeList with a CAS-based
3866 // detach-modify-reattach idiom that avoids the ABA problems
3867 // that would otherwise be present in a simple CAS-based
3868 // push-pop implementation. (push-one and pop-all)
3869 //
3870 // Caveat: Allocate() and Release() may be called from threads
3871 // other than the thread associated with the Event!
3872 // If we need to call Allocate() when running as the thread in
3873 // question then look for the PD calls to initialize native TLS.
3874 // Native TLS (Win32/Linux/Solaris) can only be initialized or
3875 // accessed by the associated thread.
3876 // See also pd_initialize().
3877 //
3878 // Note that we could defer associating a ParkEvent with a thread
3879 // until the 1st time the thread calls park(). unpark() calls to
3880 // an unprovisioned thread would be ignored. The first park() call
3881 // for a thread would allocate and associate a ParkEvent and return
3882 // immediately.
3884 volatile int ParkEvent::ListLock = 0 ;
3885 ParkEvent * volatile ParkEvent::FreeList = NULL ;
3887 ParkEvent * ParkEvent::Allocate (Thread * t) {
3888 // In rare cases -- JVM_RawMonitor* operations -- we can find t == null.
3889 ParkEvent * ev ;
3891 // Start by trying to recycle an existing but unassociated
3892 // ParkEvent from the global free list.
3893 for (;;) {
3894 ev = FreeList ;
3895 if (ev == NULL) break ;
3896 // 1: Detach - sequester or privatize the list
3897 // Tantamount to ev = Swap (&FreeList, NULL)
3898 if (Atomic::cmpxchg_ptr (NULL, &FreeList, ev) != ev) {
3899 continue ;
3900 }
3902 // We've detached the list. The list in-hand is now
3903 // local to this thread. This thread can operate on the
3904 // list without risk of interference from other threads.
3905 // 2: Extract -- pop the 1st element from the list.
3906 ParkEvent * List = ev->FreeNext ;
3907 if (List == NULL) break ;
3908 for (;;) {
3909 // 3: Try to reattach the residual list
3910 guarantee (List != NULL, "invariant") ;
3911 ParkEvent * Arv = (ParkEvent *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ;
3912 if (Arv == NULL) break ;
3914 // New nodes arrived. Try to detach the recent arrivals.
3915 if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) {
3916 continue ;
3917 }
3918 guarantee (Arv != NULL, "invariant") ;
3919 // 4: Merge Arv into List
3920 ParkEvent * Tail = List ;
3921 while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ;
3922 Tail->FreeNext = Arv ;
3923 }
3924 break ;
3925 }
3927 if (ev != NULL) {
3928 guarantee (ev->AssociatedWith == NULL, "invariant") ;
3929 } else {
3930 // Do this the hard way -- materialize a new ParkEvent.
3931 // In rare cases an allocating thread might detach a long list --
3932 // installing null into FreeList -- and then stall or be obstructed.
3933 // A 2nd thread calling Allocate() would see FreeList == null.
3934 // The list held privately by the 1st thread is unavailable to the 2nd thread.
3935 // In that case the 2nd thread would have to materialize a new ParkEvent,
3936 // even though free ParkEvents existed in the system. In this case we end up
3937 // with more ParkEvents in circulation than we need, but the race is
3938 // rare and the outcome is benign. Ideally, the # of extant ParkEvents
3939 // is equal to the maximum # of threads that existed at any one time.
3940 // Because of the race mentioned above, segments of the freelist
3941 // can be transiently inaccessible. At worst we may end up with the
3942 // # of ParkEvents in circulation slightly above the ideal.
3943 // Note that if we didn't have the TSM/immortal constraint, then
3944 // when reattaching, above, we could trim the list.
3945 ev = new ParkEvent () ;
3946 guarantee ((intptr_t(ev) & 0xFF) == 0, "invariant") ;
3947 }
3948 ev->reset() ; // courtesy to caller
3949 ev->AssociatedWith = t ; // Associate ev with t
3950 ev->FreeNext = NULL ;
3951 return ev ;
3952 }
3954 void ParkEvent::Release (ParkEvent * ev) {
3955 if (ev == NULL) return ;
3956 guarantee (ev->FreeNext == NULL , "invariant") ;
3957 ev->AssociatedWith = NULL ;
3958 for (;;) {
3959 // Push ev onto FreeList
3960 // The mechanism is "half" lock-free.
3961 ParkEvent * List = FreeList ;
3962 ev->FreeNext = List ;
3963 if (Atomic::cmpxchg_ptr (ev, &FreeList, List) == List) break ;
3964 }
3965 }
3967 // Override operator new and delete so we can ensure that the
3968 // least significant byte of ParkEvent addresses is 0.
3969 // Beware that excessive address alignment is undesirable
3970 // as it can result in D$ index usage imbalance as
3971 // well as bank access imbalance on Niagara-like platforms,
3972 // although Niagara's hash function should help.
3974 void * ParkEvent::operator new (size_t sz) {
3975 return (void *) ((intptr_t (CHeapObj::operator new (sz + 256)) + 256) & -256) ;
3976 }
3978 void ParkEvent::operator delete (void * a) {
3979 // ParkEvents are type-stable and immortal ...
3980 ShouldNotReachHere();
3981 }
3984 // 6399321 As a temporary measure we copied & modified the ParkEvent::
3985 // allocate() and release() code for use by Parkers. The Parker:: forms
3986 // will eventually be removed as we consolide and shift over to ParkEvents
3987 // for both builtin synchronization and JSR166 operations.
3989 volatile int Parker::ListLock = 0 ;
3990 Parker * volatile Parker::FreeList = NULL ;
3992 Parker * Parker::Allocate (JavaThread * t) {
3993 guarantee (t != NULL, "invariant") ;
3994 Parker * p ;
3996 // Start by trying to recycle an existing but unassociated
3997 // Parker from the global free list.
3998 for (;;) {
3999 p = FreeList ;
4000 if (p == NULL) break ;
4001 // 1: Detach
4002 // Tantamount to p = Swap (&FreeList, NULL)
4003 if (Atomic::cmpxchg_ptr (NULL, &FreeList, p) != p) {
4004 continue ;
4005 }
4007 // We've detached the list. The list in-hand is now
4008 // local to this thread. This thread can operate on the
4009 // list without risk of interference from other threads.
4010 // 2: Extract -- pop the 1st element from the list.
4011 Parker * List = p->FreeNext ;
4012 if (List == NULL) break ;
4013 for (;;) {
4014 // 3: Try to reattach the residual list
4015 guarantee (List != NULL, "invariant") ;
4016 Parker * Arv = (Parker *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ;
4017 if (Arv == NULL) break ;
4019 // New nodes arrived. Try to detach the recent arrivals.
4020 if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) {
4021 continue ;
4022 }
4023 guarantee (Arv != NULL, "invariant") ;
4024 // 4: Merge Arv into List
4025 Parker * Tail = List ;
4026 while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ;
4027 Tail->FreeNext = Arv ;
4028 }
4029 break ;
4030 }
4032 if (p != NULL) {
4033 guarantee (p->AssociatedWith == NULL, "invariant") ;
4034 } else {
4035 // Do this the hard way -- materialize a new Parker..
4036 // In rare cases an allocating thread might detach
4037 // a long list -- installing null into FreeList --and
4038 // then stall. Another thread calling Allocate() would see
4039 // FreeList == null and then invoke the ctor. In this case we
4040 // end up with more Parkers in circulation than we need, but
4041 // the race is rare and the outcome is benign.
4042 // Ideally, the # of extant Parkers is equal to the
4043 // maximum # of threads that existed at any one time.
4044 // Because of the race mentioned above, segments of the
4045 // freelist can be transiently inaccessible. At worst
4046 // we may end up with the # of Parkers in circulation
4047 // slightly above the ideal.
4048 p = new Parker() ;
4049 }
4050 p->AssociatedWith = t ; // Associate p with t
4051 p->FreeNext = NULL ;
4052 return p ;
4053 }
4056 void Parker::Release (Parker * p) {
4057 if (p == NULL) return ;
4058 guarantee (p->AssociatedWith != NULL, "invariant") ;
4059 guarantee (p->FreeNext == NULL , "invariant") ;
4060 p->AssociatedWith = NULL ;
4061 for (;;) {
4062 // Push p onto FreeList
4063 Parker * List = FreeList ;
4064 p->FreeNext = List ;
4065 if (Atomic::cmpxchg_ptr (p, &FreeList, List) == List) break ;
4066 }
4067 }
4069 void Threads::verify() {
4070 ALL_JAVA_THREADS(p) {
4071 p->verify();
4072 }
4073 VMThread* thread = VMThread::vm_thread();
4074 if (thread != NULL) thread->verify();
4075 }