Tue, 02 Nov 2010 16:02:46 -0700
6996136: VM crash in src/share/vm/runtime/virtualspace.cpp:424
Summary: Turn CDS off if compressed oops is on
Reviewed-by: ysr, kvn, jcoomes, phh
1 /*
2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 # 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 NOT_PRODUCT(_skip_gcalot = false;)
131 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
132 _jvmti_env_iteration_count = 0;
133 _vm_operation_started_count = 0;
134 _vm_operation_completed_count = 0;
135 _current_pending_monitor = NULL;
136 _current_pending_monitor_is_from_java = true;
137 _current_waiting_monitor = NULL;
138 _num_nested_signal = 0;
139 omFreeList = NULL ;
140 omFreeCount = 0 ;
141 omFreeProvision = 32 ;
142 omInUseList = NULL ;
143 omInUseCount = 0 ;
145 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
146 _suspend_flags = 0;
148 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
149 _hashStateX = os::random() ;
150 _hashStateY = 842502087 ;
151 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
152 _hashStateW = 273326509 ;
154 _OnTrap = 0 ;
155 _schedctl = NULL ;
156 _Stalled = 0 ;
157 _TypeTag = 0x2BAD ;
159 // Many of the following fields are effectively final - immutable
160 // Note that nascent threads can't use the Native Monitor-Mutex
161 // construct until the _MutexEvent is initialized ...
162 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
163 // we might instead use a stack of ParkEvents that we could provision on-demand.
164 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
165 // and ::Release()
166 _ParkEvent = ParkEvent::Allocate (this) ;
167 _SleepEvent = ParkEvent::Allocate (this) ;
168 _MutexEvent = ParkEvent::Allocate (this) ;
169 _MuxEvent = ParkEvent::Allocate (this) ;
171 #ifdef CHECK_UNHANDLED_OOPS
172 if (CheckUnhandledOops) {
173 _unhandled_oops = new UnhandledOops(this);
174 }
175 #endif // CHECK_UNHANDLED_OOPS
176 #ifdef ASSERT
177 if (UseBiasedLocking) {
178 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
179 assert(this == _real_malloc_address ||
180 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
181 "bug in forced alignment of thread objects");
182 }
183 #endif /* ASSERT */
184 }
186 void Thread::initialize_thread_local_storage() {
187 // Note: Make sure this method only calls
188 // non-blocking operations. Otherwise, it might not work
189 // with the thread-startup/safepoint interaction.
191 // During Java thread startup, safepoint code should allow this
192 // method to complete because it may need to allocate memory to
193 // store information for the new thread.
195 // initialize structure dependent on thread local storage
196 ThreadLocalStorage::set_thread(this);
198 // set up any platform-specific state.
199 os::initialize_thread();
201 }
203 void Thread::record_stack_base_and_size() {
204 set_stack_base(os::current_stack_base());
205 set_stack_size(os::current_stack_size());
206 }
209 Thread::~Thread() {
210 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
211 ObjectSynchronizer::omFlush (this) ;
213 // deallocate data structures
214 delete resource_area();
215 // since the handle marks are using the handle area, we have to deallocated the root
216 // handle mark before deallocating the thread's handle area,
217 assert(last_handle_mark() != NULL, "check we have an element");
218 delete last_handle_mark();
219 assert(last_handle_mark() == NULL, "check we have reached the end");
221 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
222 // We NULL out the fields for good hygiene.
223 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
224 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
225 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
226 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
228 delete handle_area();
230 // osthread() can be NULL, if creation of thread failed.
231 if (osthread() != NULL) os::free_thread(osthread());
233 delete _SR_lock;
235 // clear thread local storage if the Thread is deleting itself
236 if (this == Thread::current()) {
237 ThreadLocalStorage::set_thread(NULL);
238 } else {
239 // In the case where we're not the current thread, invalidate all the
240 // caches in case some code tries to get the current thread or the
241 // thread that was destroyed, and gets stale information.
242 ThreadLocalStorage::invalidate_all();
243 }
244 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
245 }
247 // NOTE: dummy function for assertion purpose.
248 void Thread::run() {
249 ShouldNotReachHere();
250 }
252 #ifdef ASSERT
253 // Private method to check for dangling thread pointer
254 void check_for_dangling_thread_pointer(Thread *thread) {
255 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
256 "possibility of dangling Thread pointer");
257 }
258 #endif
261 #ifndef PRODUCT
262 // Tracing method for basic thread operations
263 void Thread::trace(const char* msg, const Thread* const thread) {
264 if (!TraceThreadEvents) return;
265 ResourceMark rm;
266 ThreadCritical tc;
267 const char *name = "non-Java thread";
268 int prio = -1;
269 if (thread->is_Java_thread()
270 && !thread->is_Compiler_thread()) {
271 // The Threads_lock must be held to get information about
272 // this thread but may not be in some situations when
273 // tracing thread events.
274 bool release_Threads_lock = false;
275 if (!Threads_lock->owned_by_self()) {
276 Threads_lock->lock();
277 release_Threads_lock = true;
278 }
279 JavaThread* jt = (JavaThread *)thread;
280 name = (char *)jt->get_thread_name();
281 oop thread_oop = jt->threadObj();
282 if (thread_oop != NULL) {
283 prio = java_lang_Thread::priority(thread_oop);
284 }
285 if (release_Threads_lock) {
286 Threads_lock->unlock();
287 }
288 }
289 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
290 }
291 #endif
294 ThreadPriority Thread::get_priority(const Thread* const thread) {
295 trace("get priority", thread);
296 ThreadPriority priority;
297 // Can return an error!
298 (void)os::get_priority(thread, priority);
299 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
300 return priority;
301 }
303 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
304 trace("set priority", thread);
305 debug_only(check_for_dangling_thread_pointer(thread);)
306 // Can return an error!
307 (void)os::set_priority(thread, priority);
308 }
311 void Thread::start(Thread* thread) {
312 trace("start", thread);
313 // Start is different from resume in that its safety is guaranteed by context or
314 // being called from a Java method synchronized on the Thread object.
315 if (!DisableStartThread) {
316 if (thread->is_Java_thread()) {
317 // Initialize the thread state to RUNNABLE before starting this thread.
318 // Can not set it after the thread started because we do not know the
319 // exact thread state at that time. It could be in MONITOR_WAIT or
320 // in SLEEPING or some other state.
321 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
322 java_lang_Thread::RUNNABLE);
323 }
324 os::start_thread(thread);
325 }
326 }
328 // Enqueue a VM_Operation to do the job for us - sometime later
329 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
330 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
331 VMThread::execute(vm_stop);
332 }
335 //
336 // Check if an external suspend request has completed (or has been
337 // cancelled). Returns true if the thread is externally suspended and
338 // false otherwise.
339 //
340 // The bits parameter returns information about the code path through
341 // the routine. Useful for debugging:
342 //
343 // set in is_ext_suspend_completed():
344 // 0x00000001 - routine was entered
345 // 0x00000010 - routine return false at end
346 // 0x00000100 - thread exited (return false)
347 // 0x00000200 - suspend request cancelled (return false)
348 // 0x00000400 - thread suspended (return true)
349 // 0x00001000 - thread is in a suspend equivalent state (return true)
350 // 0x00002000 - thread is native and walkable (return true)
351 // 0x00004000 - thread is native_trans and walkable (needed retry)
352 //
353 // set in wait_for_ext_suspend_completion():
354 // 0x00010000 - routine was entered
355 // 0x00020000 - suspend request cancelled before loop (return false)
356 // 0x00040000 - thread suspended before loop (return true)
357 // 0x00080000 - suspend request cancelled in loop (return false)
358 // 0x00100000 - thread suspended in loop (return true)
359 // 0x00200000 - suspend not completed during retry loop (return false)
360 //
362 // Helper class for tracing suspend wait debug bits.
363 //
364 // 0x00000100 indicates that the target thread exited before it could
365 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
366 // 0x00080000 each indicate a cancelled suspend request so they don't
367 // count as wait failures either.
368 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
370 class TraceSuspendDebugBits : public StackObj {
371 private:
372 JavaThread * jt;
373 bool is_wait;
374 bool called_by_wait; // meaningful when !is_wait
375 uint32_t * bits;
377 public:
378 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
379 uint32_t *_bits) {
380 jt = _jt;
381 is_wait = _is_wait;
382 called_by_wait = _called_by_wait;
383 bits = _bits;
384 }
386 ~TraceSuspendDebugBits() {
387 if (!is_wait) {
388 #if 1
389 // By default, don't trace bits for is_ext_suspend_completed() calls.
390 // That trace is very chatty.
391 return;
392 #else
393 if (!called_by_wait) {
394 // If tracing for is_ext_suspend_completed() is enabled, then only
395 // trace calls to it from wait_for_ext_suspend_completion()
396 return;
397 }
398 #endif
399 }
401 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
402 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
403 MutexLocker ml(Threads_lock); // needed for get_thread_name()
404 ResourceMark rm;
406 tty->print_cr(
407 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
408 jt->get_thread_name(), *bits);
410 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
411 }
412 }
413 }
414 };
415 #undef DEBUG_FALSE_BITS
418 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
419 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
421 bool did_trans_retry = false; // only do thread_in_native_trans retry once
422 bool do_trans_retry; // flag to force the retry
424 *bits |= 0x00000001;
426 do {
427 do_trans_retry = false;
429 if (is_exiting()) {
430 // Thread is in the process of exiting. This is always checked
431 // first to reduce the risk of dereferencing a freed JavaThread.
432 *bits |= 0x00000100;
433 return false;
434 }
436 if (!is_external_suspend()) {
437 // Suspend request is cancelled. This is always checked before
438 // is_ext_suspended() to reduce the risk of a rogue resume
439 // confusing the thread that made the suspend request.
440 *bits |= 0x00000200;
441 return false;
442 }
444 if (is_ext_suspended()) {
445 // thread is suspended
446 *bits |= 0x00000400;
447 return true;
448 }
450 // Now that we no longer do hard suspends of threads running
451 // native code, the target thread can be changing thread state
452 // while we are in this routine:
453 //
454 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
455 //
456 // We save a copy of the thread state as observed at this moment
457 // and make our decision about suspend completeness based on the
458 // copy. This closes the race where the thread state is seen as
459 // _thread_in_native_trans in the if-thread_blocked check, but is
460 // seen as _thread_blocked in if-thread_in_native_trans check.
461 JavaThreadState save_state = thread_state();
463 if (save_state == _thread_blocked && is_suspend_equivalent()) {
464 // If the thread's state is _thread_blocked and this blocking
465 // condition is known to be equivalent to a suspend, then we can
466 // consider the thread to be externally suspended. This means that
467 // the code that sets _thread_blocked has been modified to do
468 // self-suspension if the blocking condition releases. We also
469 // used to check for CONDVAR_WAIT here, but that is now covered by
470 // the _thread_blocked with self-suspension check.
471 //
472 // Return true since we wouldn't be here unless there was still an
473 // external suspend request.
474 *bits |= 0x00001000;
475 return true;
476 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
477 // Threads running native code will self-suspend on native==>VM/Java
478 // transitions. If its stack is walkable (should always be the case
479 // unless this function is called before the actual java_suspend()
480 // call), then the wait is done.
481 *bits |= 0x00002000;
482 return true;
483 } else if (!called_by_wait && !did_trans_retry &&
484 save_state == _thread_in_native_trans &&
485 frame_anchor()->walkable()) {
486 // The thread is transitioning from thread_in_native to another
487 // thread state. check_safepoint_and_suspend_for_native_trans()
488 // will force the thread to self-suspend. If it hasn't gotten
489 // there yet we may have caught the thread in-between the native
490 // code check above and the self-suspend. Lucky us. If we were
491 // called by wait_for_ext_suspend_completion(), then it
492 // will be doing the retries so we don't have to.
493 //
494 // Since we use the saved thread state in the if-statement above,
495 // there is a chance that the thread has already transitioned to
496 // _thread_blocked by the time we get here. In that case, we will
497 // make a single unnecessary pass through the logic below. This
498 // doesn't hurt anything since we still do the trans retry.
500 *bits |= 0x00004000;
502 // Once the thread leaves thread_in_native_trans for another
503 // thread state, we break out of this retry loop. We shouldn't
504 // need this flag to prevent us from getting back here, but
505 // sometimes paranoia is good.
506 did_trans_retry = true;
508 // We wait for the thread to transition to a more usable state.
509 for (int i = 1; i <= SuspendRetryCount; i++) {
510 // We used to do an "os::yield_all(i)" call here with the intention
511 // that yielding would increase on each retry. However, the parameter
512 // is ignored on Linux which means the yield didn't scale up. Waiting
513 // on the SR_lock below provides a much more predictable scale up for
514 // the delay. It also provides a simple/direct point to check for any
515 // safepoint requests from the VMThread
517 // temporarily drops SR_lock while doing wait with safepoint check
518 // (if we're a JavaThread - the WatcherThread can also call this)
519 // and increase delay with each retry
520 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
522 // check the actual thread state instead of what we saved above
523 if (thread_state() != _thread_in_native_trans) {
524 // the thread has transitioned to another thread state so
525 // try all the checks (except this one) one more time.
526 do_trans_retry = true;
527 break;
528 }
529 } // end retry loop
532 }
533 } while (do_trans_retry);
535 *bits |= 0x00000010;
536 return false;
537 }
539 //
540 // Wait for an external suspend request to complete (or be cancelled).
541 // Returns true if the thread is externally suspended and false otherwise.
542 //
543 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
544 uint32_t *bits) {
545 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
546 false /* !called_by_wait */, bits);
548 // local flag copies to minimize SR_lock hold time
549 bool is_suspended;
550 bool pending;
551 uint32_t reset_bits;
553 // set a marker so is_ext_suspend_completed() knows we are the caller
554 *bits |= 0x00010000;
556 // We use reset_bits to reinitialize the bits value at the top of
557 // each retry loop. This allows the caller to make use of any
558 // unused bits for their own marking purposes.
559 reset_bits = *bits;
561 {
562 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
563 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
564 delay, bits);
565 pending = is_external_suspend();
566 }
567 // must release SR_lock to allow suspension to complete
569 if (!pending) {
570 // A cancelled suspend request is the only false return from
571 // is_ext_suspend_completed() that keeps us from entering the
572 // retry loop.
573 *bits |= 0x00020000;
574 return false;
575 }
577 if (is_suspended) {
578 *bits |= 0x00040000;
579 return true;
580 }
582 for (int i = 1; i <= retries; i++) {
583 *bits = reset_bits; // reinit to only track last retry
585 // We used to do an "os::yield_all(i)" call here with the intention
586 // that yielding would increase on each retry. However, the parameter
587 // is ignored on Linux which means the yield didn't scale up. Waiting
588 // on the SR_lock below provides a much more predictable scale up for
589 // the delay. It also provides a simple/direct point to check for any
590 // safepoint requests from the VMThread
592 {
593 MutexLocker ml(SR_lock());
594 // wait with safepoint check (if we're a JavaThread - the WatcherThread
595 // can also call this) and increase delay with each retry
596 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
598 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
599 delay, bits);
601 // It is possible for the external suspend request to be cancelled
602 // (by a resume) before the actual suspend operation is completed.
603 // Refresh our local copy to see if we still need to wait.
604 pending = is_external_suspend();
605 }
607 if (!pending) {
608 // A cancelled suspend request is the only false return from
609 // is_ext_suspend_completed() that keeps us from staying in the
610 // retry loop.
611 *bits |= 0x00080000;
612 return false;
613 }
615 if (is_suspended) {
616 *bits |= 0x00100000;
617 return true;
618 }
619 } // end retry loop
621 // thread did not suspend after all our retries
622 *bits |= 0x00200000;
623 return false;
624 }
626 #ifndef PRODUCT
627 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
629 // This should not need to be atomic as the only way for simultaneous
630 // updates is via interrupts. Even then this should be rare or non-existant
631 // and we don't care that much anyway.
633 int index = _jmp_ring_index;
634 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
635 _jmp_ring[index]._target = (intptr_t) target;
636 _jmp_ring[index]._instruction = (intptr_t) instr;
637 _jmp_ring[index]._file = file;
638 _jmp_ring[index]._line = line;
639 }
640 #endif /* PRODUCT */
642 // Called by flat profiler
643 // Callers have already called wait_for_ext_suspend_completion
644 // The assertion for that is currently too complex to put here:
645 bool JavaThread::profile_last_Java_frame(frame* _fr) {
646 bool gotframe = false;
647 // self suspension saves needed state.
648 if (has_last_Java_frame() && _anchor.walkable()) {
649 *_fr = pd_last_frame();
650 gotframe = true;
651 }
652 return gotframe;
653 }
655 void Thread::interrupt(Thread* thread) {
656 trace("interrupt", thread);
657 debug_only(check_for_dangling_thread_pointer(thread);)
658 os::interrupt(thread);
659 }
661 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
662 trace("is_interrupted", thread);
663 debug_only(check_for_dangling_thread_pointer(thread);)
664 // Note: If clear_interrupted==false, this simply fetches and
665 // returns the value of the field osthread()->interrupted().
666 return os::is_interrupted(thread, clear_interrupted);
667 }
670 // GC Support
671 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
672 jint thread_parity = _oops_do_parity;
673 if (thread_parity != strong_roots_parity) {
674 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
675 if (res == thread_parity) return true;
676 else {
677 guarantee(res == strong_roots_parity, "Or else what?");
678 assert(SharedHeap::heap()->n_par_threads() > 0,
679 "Should only fail when parallel.");
680 return false;
681 }
682 }
683 assert(SharedHeap::heap()->n_par_threads() > 0,
684 "Should only fail when parallel.");
685 return false;
686 }
688 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
689 active_handles()->oops_do(f);
690 // Do oop for ThreadShadow
691 f->do_oop((oop*)&_pending_exception);
692 handle_area()->oops_do(f);
693 }
695 void Thread::nmethods_do(CodeBlobClosure* cf) {
696 // no nmethods in a generic thread...
697 }
699 void Thread::print_on(outputStream* st) const {
700 // get_priority assumes osthread initialized
701 if (osthread() != NULL) {
702 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
703 osthread()->print_on(st);
704 }
705 debug_only(if (WizardMode) print_owned_locks_on(st);)
706 }
708 // Thread::print_on_error() is called by fatal error handler. Don't use
709 // any lock or allocate memory.
710 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
711 if (is_VM_thread()) st->print("VMThread");
712 else if (is_Compiler_thread()) st->print("CompilerThread");
713 else if (is_Java_thread()) st->print("JavaThread");
714 else if (is_GC_task_thread()) st->print("GCTaskThread");
715 else if (is_Watcher_thread()) st->print("WatcherThread");
716 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
717 else st->print("Thread");
719 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
720 _stack_base - _stack_size, _stack_base);
722 if (osthread()) {
723 st->print(" [id=%d]", osthread()->thread_id());
724 }
725 }
727 #ifdef ASSERT
728 void Thread::print_owned_locks_on(outputStream* st) const {
729 Monitor *cur = _owned_locks;
730 if (cur == NULL) {
731 st->print(" (no locks) ");
732 } else {
733 st->print_cr(" Locks owned:");
734 while(cur) {
735 cur->print_on(st);
736 cur = cur->next();
737 }
738 }
739 }
741 static int ref_use_count = 0;
743 bool Thread::owns_locks_but_compiled_lock() const {
744 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
745 if (cur != Compile_lock) return true;
746 }
747 return false;
748 }
751 #endif
753 #ifndef PRODUCT
755 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
756 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
757 // no threads which allow_vm_block's are held
758 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
759 // Check if current thread is allowed to block at a safepoint
760 if (!(_allow_safepoint_count == 0))
761 fatal("Possible safepoint reached by thread that does not allow it");
762 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
763 fatal("LEAF method calling lock?");
764 }
766 #ifdef ASSERT
767 if (potential_vm_operation && is_Java_thread()
768 && !Universe::is_bootstrapping()) {
769 // Make sure we do not hold any locks that the VM thread also uses.
770 // This could potentially lead to deadlocks
771 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
772 // Threads_lock is special, since the safepoint synchronization will not start before this is
773 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
774 // since it is used to transfer control between JavaThreads and the VMThread
775 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
776 if ( (cur->allow_vm_block() &&
777 cur != Threads_lock &&
778 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
779 cur != VMOperationRequest_lock &&
780 cur != VMOperationQueue_lock) ||
781 cur->rank() == Mutex::special) {
782 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
783 }
784 }
785 }
787 if (GCALotAtAllSafepoints) {
788 // We could enter a safepoint here and thus have a gc
789 InterfaceSupport::check_gc_alot();
790 }
791 #endif
792 }
793 #endif
795 bool Thread::is_in_stack(address adr) const {
796 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
797 address end = os::current_stack_pointer();
798 if (stack_base() >= adr && adr >= end) return true;
800 return false;
801 }
804 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
805 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
806 // used for compilation in the future. If that change is made, the need for these methods
807 // should be revisited, and they should be removed if possible.
809 bool Thread::is_lock_owned(address adr) const {
810 return on_local_stack(adr);
811 }
813 bool Thread::set_as_starting_thread() {
814 // NOTE: this must be called inside the main thread.
815 return os::create_main_thread((JavaThread*)this);
816 }
818 static void initialize_class(symbolHandle class_name, TRAPS) {
819 klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
820 instanceKlass::cast(klass)->initialize(CHECK);
821 }
824 // Creates the initial ThreadGroup
825 static Handle create_initial_thread_group(TRAPS) {
826 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_ThreadGroup(), true, CHECK_NH);
827 instanceKlassHandle klass (THREAD, k);
829 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
830 {
831 JavaValue result(T_VOID);
832 JavaCalls::call_special(&result,
833 system_instance,
834 klass,
835 vmSymbolHandles::object_initializer_name(),
836 vmSymbolHandles::void_method_signature(),
837 CHECK_NH);
838 }
839 Universe::set_system_thread_group(system_instance());
841 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
842 {
843 JavaValue result(T_VOID);
844 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
845 JavaCalls::call_special(&result,
846 main_instance,
847 klass,
848 vmSymbolHandles::object_initializer_name(),
849 vmSymbolHandles::threadgroup_string_void_signature(),
850 system_instance,
851 string,
852 CHECK_NH);
853 }
854 return main_instance;
855 }
857 // Creates the initial Thread
858 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
859 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK_NULL);
860 instanceKlassHandle klass (THREAD, k);
861 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
863 java_lang_Thread::set_thread(thread_oop(), thread);
864 java_lang_Thread::set_priority(thread_oop(), NormPriority);
865 thread->set_threadObj(thread_oop());
867 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
869 JavaValue result(T_VOID);
870 JavaCalls::call_special(&result, thread_oop,
871 klass,
872 vmSymbolHandles::object_initializer_name(),
873 vmSymbolHandles::threadgroup_string_void_signature(),
874 thread_group,
875 string,
876 CHECK_NULL);
877 return thread_oop();
878 }
880 static void call_initializeSystemClass(TRAPS) {
881 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
882 instanceKlassHandle klass (THREAD, k);
884 JavaValue result(T_VOID);
885 JavaCalls::call_static(&result, klass, vmSymbolHandles::initializeSystemClass_name(),
886 vmSymbolHandles::void_method_signature(), CHECK);
887 }
889 #ifdef KERNEL
890 static void set_jkernel_boot_classloader_hook(TRAPS) {
891 klassOop k = SystemDictionary::sun_jkernel_DownloadManager_klass();
892 instanceKlassHandle klass (THREAD, k);
894 if (k == NULL) {
895 // sun.jkernel.DownloadManager may not present in the JDK; just return
896 return;
897 }
899 JavaValue result(T_VOID);
900 JavaCalls::call_static(&result, klass, vmSymbolHandles::setBootClassLoaderHook_name(),
901 vmSymbolHandles::void_method_signature(), CHECK);
902 }
903 #endif // KERNEL
905 static void reset_vm_info_property(TRAPS) {
906 // the vm info string
907 ResourceMark rm(THREAD);
908 const char *vm_info = VM_Version::vm_info_string();
910 // java.lang.System class
911 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
912 instanceKlassHandle klass (THREAD, k);
914 // setProperty arguments
915 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
916 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
918 // return value
919 JavaValue r(T_OBJECT);
921 // public static String setProperty(String key, String value);
922 JavaCalls::call_static(&r,
923 klass,
924 vmSymbolHandles::setProperty_name(),
925 vmSymbolHandles::string_string_string_signature(),
926 key_str,
927 value_str,
928 CHECK);
929 }
932 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
933 assert(thread_group.not_null(), "thread group should be specified");
934 assert(threadObj() == NULL, "should only create Java thread object once");
936 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
937 instanceKlassHandle klass (THREAD, k);
938 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
940 java_lang_Thread::set_thread(thread_oop(), this);
941 java_lang_Thread::set_priority(thread_oop(), NormPriority);
942 set_threadObj(thread_oop());
944 JavaValue result(T_VOID);
945 if (thread_name != NULL) {
946 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
947 // Thread gets assigned specified name and null target
948 JavaCalls::call_special(&result,
949 thread_oop,
950 klass,
951 vmSymbolHandles::object_initializer_name(),
952 vmSymbolHandles::threadgroup_string_void_signature(),
953 thread_group, // Argument 1
954 name, // Argument 2
955 THREAD);
956 } else {
957 // Thread gets assigned name "Thread-nnn" and null target
958 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
959 JavaCalls::call_special(&result,
960 thread_oop,
961 klass,
962 vmSymbolHandles::object_initializer_name(),
963 vmSymbolHandles::threadgroup_runnable_void_signature(),
964 thread_group, // Argument 1
965 Handle(), // Argument 2
966 THREAD);
967 }
970 if (daemon) {
971 java_lang_Thread::set_daemon(thread_oop());
972 }
974 if (HAS_PENDING_EXCEPTION) {
975 return;
976 }
978 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
979 Handle threadObj(this, this->threadObj());
981 JavaCalls::call_special(&result,
982 thread_group,
983 group,
984 vmSymbolHandles::add_method_name(),
985 vmSymbolHandles::thread_void_signature(),
986 threadObj, // Arg 1
987 THREAD);
990 }
992 // NamedThread -- non-JavaThread subclasses with multiple
993 // uniquely named instances should derive from this.
994 NamedThread::NamedThread() : Thread() {
995 _name = NULL;
996 _processed_thread = NULL;
997 }
999 NamedThread::~NamedThread() {
1000 if (_name != NULL) {
1001 FREE_C_HEAP_ARRAY(char, _name);
1002 _name = NULL;
1003 }
1004 }
1006 void NamedThread::set_name(const char* format, ...) {
1007 guarantee(_name == NULL, "Only get to set name once.");
1008 _name = NEW_C_HEAP_ARRAY(char, max_name_len);
1009 guarantee(_name != NULL, "alloc failure");
1010 va_list ap;
1011 va_start(ap, format);
1012 jio_vsnprintf(_name, max_name_len, format, ap);
1013 va_end(ap);
1014 }
1016 // ======= WatcherThread ========
1018 // The watcher thread exists to simulate timer interrupts. It should
1019 // be replaced by an abstraction over whatever native support for
1020 // timer interrupts exists on the platform.
1022 WatcherThread* WatcherThread::_watcher_thread = NULL;
1023 volatile bool WatcherThread::_should_terminate = false;
1025 WatcherThread::WatcherThread() : Thread() {
1026 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1027 if (os::create_thread(this, os::watcher_thread)) {
1028 _watcher_thread = this;
1030 // Set the watcher thread to the highest OS priority which should not be
1031 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1032 // is created. The only normal thread using this priority is the reference
1033 // handler thread, which runs for very short intervals only.
1034 // If the VMThread's priority is not lower than the WatcherThread profiling
1035 // will be inaccurate.
1036 os::set_priority(this, MaxPriority);
1037 if (!DisableStartThread) {
1038 os::start_thread(this);
1039 }
1040 }
1041 }
1043 void WatcherThread::run() {
1044 assert(this == watcher_thread(), "just checking");
1046 this->record_stack_base_and_size();
1047 this->initialize_thread_local_storage();
1048 this->set_active_handles(JNIHandleBlock::allocate_block());
1049 while(!_should_terminate) {
1050 assert(watcher_thread() == Thread::current(), "thread consistency check");
1051 assert(watcher_thread() == this, "thread consistency check");
1053 // Calculate how long it'll be until the next PeriodicTask work
1054 // should be done, and sleep that amount of time.
1055 size_t time_to_wait = PeriodicTask::time_to_wait();
1057 // we expect this to timeout - we only ever get unparked when
1058 // we should terminate
1059 {
1060 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1062 jlong prev_time = os::javaTimeNanos();
1063 for (;;) {
1064 int res= _SleepEvent->park(time_to_wait);
1065 if (res == OS_TIMEOUT || _should_terminate)
1066 break;
1067 // spurious wakeup of some kind
1068 jlong now = os::javaTimeNanos();
1069 time_to_wait -= (now - prev_time) / 1000000;
1070 if (time_to_wait <= 0)
1071 break;
1072 prev_time = now;
1073 }
1074 }
1076 if (is_error_reported()) {
1077 // A fatal error has happened, the error handler(VMError::report_and_die)
1078 // should abort JVM after creating an error log file. However in some
1079 // rare cases, the error handler itself might deadlock. Here we try to
1080 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1081 //
1082 // This code is in WatcherThread because WatcherThread wakes up
1083 // periodically so the fatal error handler doesn't need to do anything;
1084 // also because the WatcherThread is less likely to crash than other
1085 // threads.
1087 for (;;) {
1088 if (!ShowMessageBoxOnError
1089 && (OnError == NULL || OnError[0] == '\0')
1090 && Arguments::abort_hook() == NULL) {
1091 os::sleep(this, 2 * 60 * 1000, false);
1092 fdStream err(defaultStream::output_fd());
1093 err.print_raw_cr("# [ timer expired, abort... ]");
1094 // skip atexit/vm_exit/vm_abort hooks
1095 os::die();
1096 }
1098 // Wake up 5 seconds later, the fatal handler may reset OnError or
1099 // ShowMessageBoxOnError when it is ready to abort.
1100 os::sleep(this, 5 * 1000, false);
1101 }
1102 }
1104 PeriodicTask::real_time_tick(time_to_wait);
1106 // If we have no more tasks left due to dynamic disenrollment,
1107 // shut down the thread since we don't currently support dynamic enrollment
1108 if (PeriodicTask::num_tasks() == 0) {
1109 _should_terminate = true;
1110 }
1111 }
1113 // Signal that it is terminated
1114 {
1115 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1116 _watcher_thread = NULL;
1117 Terminator_lock->notify();
1118 }
1120 // Thread destructor usually does this..
1121 ThreadLocalStorage::set_thread(NULL);
1122 }
1124 void WatcherThread::start() {
1125 if (watcher_thread() == NULL) {
1126 _should_terminate = false;
1127 // Create the single instance of WatcherThread
1128 new WatcherThread();
1129 }
1130 }
1132 void WatcherThread::stop() {
1133 // it is ok to take late safepoints here, if needed
1134 MutexLocker mu(Terminator_lock);
1135 _should_terminate = true;
1136 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1138 Thread* watcher = watcher_thread();
1139 if (watcher != NULL)
1140 watcher->_SleepEvent->unpark();
1142 while(watcher_thread() != NULL) {
1143 // This wait should make safepoint checks, wait without a timeout,
1144 // and wait as a suspend-equivalent condition.
1145 //
1146 // Note: If the FlatProfiler is running, then this thread is waiting
1147 // for the WatcherThread to terminate and the WatcherThread, via the
1148 // FlatProfiler task, is waiting for the external suspend request on
1149 // this thread to complete. wait_for_ext_suspend_completion() will
1150 // eventually timeout, but that takes time. Making this wait a
1151 // suspend-equivalent condition solves that timeout problem.
1152 //
1153 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1154 Mutex::_as_suspend_equivalent_flag);
1155 }
1156 }
1158 void WatcherThread::print_on(outputStream* st) const {
1159 st->print("\"%s\" ", name());
1160 Thread::print_on(st);
1161 st->cr();
1162 }
1164 // ======= JavaThread ========
1166 // A JavaThread is a normal Java thread
1168 void JavaThread::initialize() {
1169 // Initialize fields
1171 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1172 set_claimed_par_id(-1);
1174 set_saved_exception_pc(NULL);
1175 set_threadObj(NULL);
1176 _anchor.clear();
1177 set_entry_point(NULL);
1178 set_jni_functions(jni_functions());
1179 set_callee_target(NULL);
1180 set_vm_result(NULL);
1181 set_vm_result_2(NULL);
1182 set_vframe_array_head(NULL);
1183 set_vframe_array_last(NULL);
1184 set_deferred_locals(NULL);
1185 set_deopt_mark(NULL);
1186 set_deopt_nmethod(NULL);
1187 clear_must_deopt_id();
1188 set_monitor_chunks(NULL);
1189 set_next(NULL);
1190 set_thread_state(_thread_new);
1191 _terminated = _not_terminated;
1192 _privileged_stack_top = NULL;
1193 _array_for_gc = NULL;
1194 _suspend_equivalent = false;
1195 _in_deopt_handler = 0;
1196 _doing_unsafe_access = false;
1197 _stack_guard_state = stack_guard_unused;
1198 _exception_oop = NULL;
1199 _exception_pc = 0;
1200 _exception_handler_pc = 0;
1201 _exception_stack_size = 0;
1202 _jvmti_thread_state= NULL;
1203 _should_post_on_exceptions_flag = JNI_FALSE;
1204 _jvmti_get_loaded_classes_closure = NULL;
1205 _interp_only_mode = 0;
1206 _special_runtime_exit_condition = _no_async_condition;
1207 _pending_async_exception = NULL;
1208 _is_compiling = false;
1209 _thread_stat = NULL;
1210 _thread_stat = new ThreadStatistics();
1211 _blocked_on_compilation = false;
1212 _jni_active_critical = 0;
1213 _do_not_unlock_if_synchronized = false;
1214 _cached_monitor_info = NULL;
1215 _parker = Parker::Allocate(this) ;
1217 #ifndef PRODUCT
1218 _jmp_ring_index = 0;
1219 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1220 record_jump(NULL, NULL, NULL, 0);
1221 }
1222 #endif /* PRODUCT */
1224 set_thread_profiler(NULL);
1225 if (FlatProfiler::is_active()) {
1226 // This is where we would decide to either give each thread it's own profiler
1227 // or use one global one from FlatProfiler,
1228 // or up to some count of the number of profiled threads, etc.
1229 ThreadProfiler* pp = new ThreadProfiler();
1230 pp->engage();
1231 set_thread_profiler(pp);
1232 }
1234 // Setup safepoint state info for this thread
1235 ThreadSafepointState::create(this);
1237 debug_only(_java_call_counter = 0);
1239 // JVMTI PopFrame support
1240 _popframe_condition = popframe_inactive;
1241 _popframe_preserved_args = NULL;
1242 _popframe_preserved_args_size = 0;
1244 pd_initialize();
1245 }
1247 #ifndef SERIALGC
1248 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1249 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1250 #endif // !SERIALGC
1252 JavaThread::JavaThread(bool is_attaching) :
1253 Thread()
1254 #ifndef SERIALGC
1255 , _satb_mark_queue(&_satb_mark_queue_set),
1256 _dirty_card_queue(&_dirty_card_queue_set)
1257 #endif // !SERIALGC
1258 {
1259 initialize();
1260 _is_attaching = is_attaching;
1261 assert(_deferred_card_mark.is_empty(), "Default MemRegion ctor");
1262 }
1264 bool JavaThread::reguard_stack(address cur_sp) {
1265 if (_stack_guard_state != stack_guard_yellow_disabled) {
1266 return true; // Stack already guarded or guard pages not needed.
1267 }
1269 if (register_stack_overflow()) {
1270 // For those architectures which have separate register and
1271 // memory stacks, we must check the register stack to see if
1272 // it has overflowed.
1273 return false;
1274 }
1276 // Java code never executes within the yellow zone: the latter is only
1277 // there to provoke an exception during stack banging. If java code
1278 // is executing there, either StackShadowPages should be larger, or
1279 // some exception code in c1, c2 or the interpreter isn't unwinding
1280 // when it should.
1281 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1283 enable_stack_yellow_zone();
1284 return true;
1285 }
1287 bool JavaThread::reguard_stack(void) {
1288 return reguard_stack(os::current_stack_pointer());
1289 }
1292 void JavaThread::block_if_vm_exited() {
1293 if (_terminated == _vm_exited) {
1294 // _vm_exited is set at safepoint, and Threads_lock is never released
1295 // we will block here forever
1296 Threads_lock->lock_without_safepoint_check();
1297 ShouldNotReachHere();
1298 }
1299 }
1302 // Remove this ifdef when C1 is ported to the compiler interface.
1303 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1305 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1306 Thread()
1307 #ifndef SERIALGC
1308 , _satb_mark_queue(&_satb_mark_queue_set),
1309 _dirty_card_queue(&_dirty_card_queue_set)
1310 #endif // !SERIALGC
1311 {
1312 if (TraceThreadEvents) {
1313 tty->print_cr("creating thread %p", this);
1314 }
1315 initialize();
1316 _is_attaching = false;
1317 set_entry_point(entry_point);
1318 // Create the native thread itself.
1319 // %note runtime_23
1320 os::ThreadType thr_type = os::java_thread;
1321 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1322 os::java_thread;
1323 os::create_thread(this, thr_type, stack_sz);
1325 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1326 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1327 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1328 // the exception consists of creating the exception object & initializing it, initialization
1329 // will leave the VM via a JavaCall and then all locks must be unlocked).
1330 //
1331 // The thread is still suspended when we reach here. Thread must be explicit started
1332 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1333 // by calling Threads:add. The reason why this is not done here, is because the thread
1334 // object must be fully initialized (take a look at JVM_Start)
1335 }
1337 JavaThread::~JavaThread() {
1338 if (TraceThreadEvents) {
1339 tty->print_cr("terminate thread %p", this);
1340 }
1342 // JSR166 -- return the parker to the free list
1343 Parker::Release(_parker);
1344 _parker = NULL ;
1346 // Free any remaining previous UnrollBlock
1347 vframeArray* old_array = vframe_array_last();
1349 if (old_array != NULL) {
1350 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1351 old_array->set_unroll_block(NULL);
1352 delete old_info;
1353 delete old_array;
1354 }
1356 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1357 if (deferred != NULL) {
1358 // This can only happen if thread is destroyed before deoptimization occurs.
1359 assert(deferred->length() != 0, "empty array!");
1360 do {
1361 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1362 deferred->remove_at(0);
1363 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1364 delete dlv;
1365 } while (deferred->length() != 0);
1366 delete deferred;
1367 }
1369 // All Java related clean up happens in exit
1370 ThreadSafepointState::destroy(this);
1371 if (_thread_profiler != NULL) delete _thread_profiler;
1372 if (_thread_stat != NULL) delete _thread_stat;
1373 }
1376 // The first routine called by a new Java thread
1377 void JavaThread::run() {
1378 // initialize thread-local alloc buffer related fields
1379 this->initialize_tlab();
1381 // used to test validitity of stack trace backs
1382 this->record_base_of_stack_pointer();
1384 // Record real stack base and size.
1385 this->record_stack_base_and_size();
1387 // Initialize thread local storage; set before calling MutexLocker
1388 this->initialize_thread_local_storage();
1390 this->create_stack_guard_pages();
1392 this->cache_global_variables();
1394 // Thread is now sufficient initialized to be handled by the safepoint code as being
1395 // in the VM. Change thread state from _thread_new to _thread_in_vm
1396 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1398 assert(JavaThread::current() == this, "sanity check");
1399 assert(!Thread::current()->owns_locks(), "sanity check");
1401 DTRACE_THREAD_PROBE(start, this);
1403 // This operation might block. We call that after all safepoint checks for a new thread has
1404 // been completed.
1405 this->set_active_handles(JNIHandleBlock::allocate_block());
1407 if (JvmtiExport::should_post_thread_life()) {
1408 JvmtiExport::post_thread_start(this);
1409 }
1411 // We call another function to do the rest so we are sure that the stack addresses used
1412 // from there will be lower than the stack base just computed
1413 thread_main_inner();
1415 // Note, thread is no longer valid at this point!
1416 }
1419 void JavaThread::thread_main_inner() {
1420 assert(JavaThread::current() == this, "sanity check");
1421 assert(this->threadObj() != NULL, "just checking");
1423 // Execute thread entry point. If this thread is being asked to restart,
1424 // or has been stopped before starting, do not reexecute entry point.
1425 // Note: Due to JVM_StopThread we can have pending exceptions already!
1426 if (!this->has_pending_exception() && !java_lang_Thread::is_stillborn(this->threadObj())) {
1427 // enter the thread's entry point only if we have no pending exceptions
1428 HandleMark hm(this);
1429 this->entry_point()(this, this);
1430 }
1432 DTRACE_THREAD_PROBE(stop, this);
1434 this->exit(false);
1435 delete this;
1436 }
1439 static void ensure_join(JavaThread* thread) {
1440 // We do not need to grap the Threads_lock, since we are operating on ourself.
1441 Handle threadObj(thread, thread->threadObj());
1442 assert(threadObj.not_null(), "java thread object must exist");
1443 ObjectLocker lock(threadObj, thread);
1444 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1445 thread->clear_pending_exception();
1446 // It is of profound importance that we set the stillborn bit and reset the thread object,
1447 // before we do the notify. Since, changing these two variable will make JVM_IsAlive return
1448 // false. So in case another thread is doing a join on this thread , it will detect that the thread
1449 // is dead when it gets notified.
1450 java_lang_Thread::set_stillborn(threadObj());
1451 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1452 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1453 java_lang_Thread::set_thread(threadObj(), NULL);
1454 lock.notify_all(thread);
1455 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1456 thread->clear_pending_exception();
1457 }
1460 // For any new cleanup additions, please check to see if they need to be applied to
1461 // cleanup_failed_attach_current_thread as well.
1462 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1463 assert(this == JavaThread::current(), "thread consistency check");
1464 if (!InitializeJavaLangSystem) return;
1466 HandleMark hm(this);
1467 Handle uncaught_exception(this, this->pending_exception());
1468 this->clear_pending_exception();
1469 Handle threadObj(this, this->threadObj());
1470 assert(threadObj.not_null(), "Java thread object should be created");
1472 if (get_thread_profiler() != NULL) {
1473 get_thread_profiler()->disengage();
1474 ResourceMark rm;
1475 get_thread_profiler()->print(get_thread_name());
1476 }
1479 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1480 {
1481 EXCEPTION_MARK;
1483 CLEAR_PENDING_EXCEPTION;
1484 }
1485 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1486 // has to be fixed by a runtime query method
1487 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1488 // JSR-166: change call from from ThreadGroup.uncaughtException to
1489 // java.lang.Thread.dispatchUncaughtException
1490 if (uncaught_exception.not_null()) {
1491 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1492 Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT",
1493 (address)uncaught_exception(), (address)threadObj(), (address)group());
1494 {
1495 EXCEPTION_MARK;
1496 // Check if the method Thread.dispatchUncaughtException() exists. If so
1497 // call it. Otherwise we have an older library without the JSR-166 changes,
1498 // so call ThreadGroup.uncaughtException()
1499 KlassHandle recvrKlass(THREAD, threadObj->klass());
1500 CallInfo callinfo;
1501 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1502 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1503 vmSymbolHandles::dispatchUncaughtException_name(),
1504 vmSymbolHandles::throwable_void_signature(),
1505 KlassHandle(), false, false, THREAD);
1506 CLEAR_PENDING_EXCEPTION;
1507 methodHandle method = callinfo.selected_method();
1508 if (method.not_null()) {
1509 JavaValue result(T_VOID);
1510 JavaCalls::call_virtual(&result,
1511 threadObj, thread_klass,
1512 vmSymbolHandles::dispatchUncaughtException_name(),
1513 vmSymbolHandles::throwable_void_signature(),
1514 uncaught_exception,
1515 THREAD);
1516 } else {
1517 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1518 JavaValue result(T_VOID);
1519 JavaCalls::call_virtual(&result,
1520 group, thread_group,
1521 vmSymbolHandles::uncaughtException_name(),
1522 vmSymbolHandles::thread_throwable_void_signature(),
1523 threadObj, // Arg 1
1524 uncaught_exception, // Arg 2
1525 THREAD);
1526 }
1527 CLEAR_PENDING_EXCEPTION;
1528 }
1529 }
1531 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1532 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1533 // is deprecated anyhow.
1534 { int count = 3;
1535 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1536 EXCEPTION_MARK;
1537 JavaValue result(T_VOID);
1538 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1539 JavaCalls::call_virtual(&result,
1540 threadObj, thread_klass,
1541 vmSymbolHandles::exit_method_name(),
1542 vmSymbolHandles::void_method_signature(),
1543 THREAD);
1544 CLEAR_PENDING_EXCEPTION;
1545 }
1546 }
1548 // notify JVMTI
1549 if (JvmtiExport::should_post_thread_life()) {
1550 JvmtiExport::post_thread_end(this);
1551 }
1553 // We have notified the agents that we are exiting, before we go on,
1554 // we must check for a pending external suspend request and honor it
1555 // in order to not surprise the thread that made the suspend request.
1556 while (true) {
1557 {
1558 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1559 if (!is_external_suspend()) {
1560 set_terminated(_thread_exiting);
1561 ThreadService::current_thread_exiting(this);
1562 break;
1563 }
1564 // Implied else:
1565 // Things get a little tricky here. We have a pending external
1566 // suspend request, but we are holding the SR_lock so we
1567 // can't just self-suspend. So we temporarily drop the lock
1568 // and then self-suspend.
1569 }
1571 ThreadBlockInVM tbivm(this);
1572 java_suspend_self();
1574 // We're done with this suspend request, but we have to loop around
1575 // and check again. Eventually we will get SR_lock without a pending
1576 // external suspend request and will be able to mark ourselves as
1577 // exiting.
1578 }
1579 // no more external suspends are allowed at this point
1580 } else {
1581 // before_exit() has already posted JVMTI THREAD_END events
1582 }
1584 // Notify waiters on thread object. This has to be done after exit() is called
1585 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1586 // group should have the destroyed bit set before waiters are notified).
1587 ensure_join(this);
1588 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1590 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1591 // held by this thread must be released. A detach operation must only
1592 // get here if there are no Java frames on the stack. Therefore, any
1593 // owned monitors at this point MUST be JNI-acquired monitors which are
1594 // pre-inflated and in the monitor cache.
1595 //
1596 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1597 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1598 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1599 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1600 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1601 }
1603 // These things needs to be done while we are still a Java Thread. Make sure that thread
1604 // is in a consistent state, in case GC happens
1605 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1607 if (active_handles() != NULL) {
1608 JNIHandleBlock* block = active_handles();
1609 set_active_handles(NULL);
1610 JNIHandleBlock::release_block(block);
1611 }
1613 if (free_handle_block() != NULL) {
1614 JNIHandleBlock* block = free_handle_block();
1615 set_free_handle_block(NULL);
1616 JNIHandleBlock::release_block(block);
1617 }
1619 // These have to be removed while this is still a valid thread.
1620 remove_stack_guard_pages();
1622 if (UseTLAB) {
1623 tlab().make_parsable(true); // retire TLAB
1624 }
1626 if (jvmti_thread_state() != NULL) {
1627 JvmtiExport::cleanup_thread(this);
1628 }
1630 #ifndef SERIALGC
1631 // We must flush G1-related buffers before removing a thread from
1632 // the list of active threads.
1633 if (UseG1GC) {
1634 flush_barrier_queues();
1635 }
1636 #endif
1638 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1639 Threads::remove(this);
1640 }
1642 #ifndef SERIALGC
1643 // Flush G1-related queues.
1644 void JavaThread::flush_barrier_queues() {
1645 satb_mark_queue().flush();
1646 dirty_card_queue().flush();
1647 }
1649 void JavaThread::initialize_queues() {
1650 assert(!SafepointSynchronize::is_at_safepoint(),
1651 "we should not be at a safepoint");
1653 ObjPtrQueue& satb_queue = satb_mark_queue();
1654 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1655 // The SATB queue should have been constructed with its active
1656 // field set to false.
1657 assert(!satb_queue.is_active(), "SATB queue should not be active");
1658 assert(satb_queue.is_empty(), "SATB queue should be empty");
1659 // If we are creating the thread during a marking cycle, we should
1660 // set the active field of the SATB queue to true.
1661 if (satb_queue_set.is_active()) {
1662 satb_queue.set_active(true);
1663 }
1665 DirtyCardQueue& dirty_queue = dirty_card_queue();
1666 // The dirty card queue should have been constructed with its
1667 // active field set to true.
1668 assert(dirty_queue.is_active(), "dirty card queue should be active");
1669 }
1670 #endif // !SERIALGC
1672 void JavaThread::cleanup_failed_attach_current_thread() {
1673 if (get_thread_profiler() != NULL) {
1674 get_thread_profiler()->disengage();
1675 ResourceMark rm;
1676 get_thread_profiler()->print(get_thread_name());
1677 }
1679 if (active_handles() != NULL) {
1680 JNIHandleBlock* block = active_handles();
1681 set_active_handles(NULL);
1682 JNIHandleBlock::release_block(block);
1683 }
1685 if (free_handle_block() != NULL) {
1686 JNIHandleBlock* block = free_handle_block();
1687 set_free_handle_block(NULL);
1688 JNIHandleBlock::release_block(block);
1689 }
1691 // These have to be removed while this is still a valid thread.
1692 remove_stack_guard_pages();
1694 if (UseTLAB) {
1695 tlab().make_parsable(true); // retire TLAB, if any
1696 }
1698 #ifndef SERIALGC
1699 if (UseG1GC) {
1700 flush_barrier_queues();
1701 }
1702 #endif
1704 Threads::remove(this);
1705 delete this;
1706 }
1711 JavaThread* JavaThread::active() {
1712 Thread* thread = ThreadLocalStorage::thread();
1713 assert(thread != NULL, "just checking");
1714 if (thread->is_Java_thread()) {
1715 return (JavaThread*) thread;
1716 } else {
1717 assert(thread->is_VM_thread(), "this must be a vm thread");
1718 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1719 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1720 assert(ret->is_Java_thread(), "must be a Java thread");
1721 return ret;
1722 }
1723 }
1725 bool JavaThread::is_lock_owned(address adr) const {
1726 if (Thread::is_lock_owned(adr)) return true;
1728 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1729 if (chunk->contains(adr)) return true;
1730 }
1732 return false;
1733 }
1736 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1737 chunk->set_next(monitor_chunks());
1738 set_monitor_chunks(chunk);
1739 }
1741 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1742 guarantee(monitor_chunks() != NULL, "must be non empty");
1743 if (monitor_chunks() == chunk) {
1744 set_monitor_chunks(chunk->next());
1745 } else {
1746 MonitorChunk* prev = monitor_chunks();
1747 while (prev->next() != chunk) prev = prev->next();
1748 prev->set_next(chunk->next());
1749 }
1750 }
1752 // JVM support.
1754 // Note: this function shouldn't block if it's called in
1755 // _thread_in_native_trans state (such as from
1756 // check_special_condition_for_native_trans()).
1757 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1759 if (has_last_Java_frame() && has_async_condition()) {
1760 // If we are at a polling page safepoint (not a poll return)
1761 // then we must defer async exception because live registers
1762 // will be clobbered by the exception path. Poll return is
1763 // ok because the call we a returning from already collides
1764 // with exception handling registers and so there is no issue.
1765 // (The exception handling path kills call result registers but
1766 // this is ok since the exception kills the result anyway).
1768 if (is_at_poll_safepoint()) {
1769 // if the code we are returning to has deoptimized we must defer
1770 // the exception otherwise live registers get clobbered on the
1771 // exception path before deoptimization is able to retrieve them.
1772 //
1773 RegisterMap map(this, false);
1774 frame caller_fr = last_frame().sender(&map);
1775 assert(caller_fr.is_compiled_frame(), "what?");
1776 if (caller_fr.is_deoptimized_frame()) {
1777 if (TraceExceptions) {
1778 ResourceMark rm;
1779 tty->print_cr("deferred async exception at compiled safepoint");
1780 }
1781 return;
1782 }
1783 }
1784 }
1786 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
1787 if (condition == _no_async_condition) {
1788 // Conditions have changed since has_special_runtime_exit_condition()
1789 // was called:
1790 // - if we were here only because of an external suspend request,
1791 // then that was taken care of above (or cancelled) so we are done
1792 // - if we were here because of another async request, then it has
1793 // been cleared between the has_special_runtime_exit_condition()
1794 // and now so again we are done
1795 return;
1796 }
1798 // Check for pending async. exception
1799 if (_pending_async_exception != NULL) {
1800 // Only overwrite an already pending exception, if it is not a threadDeath.
1801 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
1803 // We cannot call Exceptions::_throw(...) here because we cannot block
1804 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
1806 if (TraceExceptions) {
1807 ResourceMark rm;
1808 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
1809 if (has_last_Java_frame() ) {
1810 frame f = last_frame();
1811 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
1812 }
1813 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1814 }
1815 _pending_async_exception = NULL;
1816 clear_has_async_exception();
1817 }
1818 }
1820 if (check_unsafe_error &&
1821 condition == _async_unsafe_access_error && !has_pending_exception()) {
1822 condition = _no_async_condition; // done
1823 switch (thread_state()) {
1824 case _thread_in_vm:
1825 {
1826 JavaThread* THREAD = this;
1827 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1828 }
1829 case _thread_in_native:
1830 {
1831 ThreadInVMfromNative tiv(this);
1832 JavaThread* THREAD = this;
1833 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1834 }
1835 case _thread_in_Java:
1836 {
1837 ThreadInVMfromJava tiv(this);
1838 JavaThread* THREAD = this;
1839 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
1840 }
1841 default:
1842 ShouldNotReachHere();
1843 }
1844 }
1846 assert(condition == _no_async_condition || has_pending_exception() ||
1847 (!check_unsafe_error && condition == _async_unsafe_access_error),
1848 "must have handled the async condition, if no exception");
1849 }
1851 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
1852 //
1853 // Check for pending external suspend. Internal suspend requests do
1854 // not use handle_special_runtime_exit_condition().
1855 // If JNIEnv proxies are allowed, don't self-suspend if the target
1856 // thread is not the current thread. In older versions of jdbx, jdbx
1857 // threads could call into the VM with another thread's JNIEnv so we
1858 // can be here operating on behalf of a suspended thread (4432884).
1859 bool do_self_suspend = is_external_suspend_with_lock();
1860 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
1861 //
1862 // Because thread is external suspended the safepoint code will count
1863 // thread as at a safepoint. This can be odd because we can be here
1864 // as _thread_in_Java which would normally transition to _thread_blocked
1865 // at a safepoint. We would like to mark the thread as _thread_blocked
1866 // before calling java_suspend_self like all other callers of it but
1867 // we must then observe proper safepoint protocol. (We can't leave
1868 // _thread_blocked with a safepoint in progress). However we can be
1869 // here as _thread_in_native_trans so we can't use a normal transition
1870 // constructor/destructor pair because they assert on that type of
1871 // transition. We could do something like:
1872 //
1873 // JavaThreadState state = thread_state();
1874 // set_thread_state(_thread_in_vm);
1875 // {
1876 // ThreadBlockInVM tbivm(this);
1877 // java_suspend_self()
1878 // }
1879 // set_thread_state(_thread_in_vm_trans);
1880 // if (safepoint) block;
1881 // set_thread_state(state);
1882 //
1883 // but that is pretty messy. Instead we just go with the way the
1884 // code has worked before and note that this is the only path to
1885 // java_suspend_self that doesn't put the thread in _thread_blocked
1886 // mode.
1888 frame_anchor()->make_walkable(this);
1889 java_suspend_self();
1891 // We might be here for reasons in addition to the self-suspend request
1892 // so check for other async requests.
1893 }
1895 if (check_asyncs) {
1896 check_and_handle_async_exceptions();
1897 }
1898 }
1900 void JavaThread::send_thread_stop(oop java_throwable) {
1901 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
1902 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
1903 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
1905 // Do not throw asynchronous exceptions against the compiler thread
1906 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
1907 if (is_Compiler_thread()) return;
1909 // This is a change from JDK 1.1, but JDK 1.2 will also do it:
1910 if (java_throwable->is_a(SystemDictionary::ThreadDeath_klass())) {
1911 java_lang_Thread::set_stillborn(threadObj());
1912 }
1914 {
1915 // Actually throw the Throwable against the target Thread - however
1916 // only if there is no thread death exception installed already.
1917 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
1918 // If the topmost frame is a runtime stub, then we are calling into
1919 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1920 // must deoptimize the caller before continuing, as the compiled exception handler table
1921 // may not be valid
1922 if (has_last_Java_frame()) {
1923 frame f = last_frame();
1924 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
1925 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
1926 RegisterMap reg_map(this, UseBiasedLocking);
1927 frame compiled_frame = f.sender(®_map);
1928 if (compiled_frame.can_be_deoptimized()) {
1929 Deoptimization::deoptimize(this, compiled_frame, ®_map);
1930 }
1931 }
1932 }
1934 // Set async. pending exception in thread.
1935 set_pending_async_exception(java_throwable);
1937 if (TraceExceptions) {
1938 ResourceMark rm;
1939 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1940 }
1941 // for AbortVMOnException flag
1942 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
1943 }
1944 }
1947 // Interrupt thread so it will wake up from a potential wait()
1948 Thread::interrupt(this);
1949 }
1951 // External suspension mechanism.
1952 //
1953 // Tell the VM to suspend a thread when ever it knows that it does not hold on
1954 // to any VM_locks and it is at a transition
1955 // Self-suspension will happen on the transition out of the vm.
1956 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
1957 //
1958 // Guarantees on return:
1959 // + Target thread will not execute any new bytecode (that's why we need to
1960 // force a safepoint)
1961 // + Target thread will not enter any new monitors
1962 //
1963 void JavaThread::java_suspend() {
1964 { MutexLocker mu(Threads_lock);
1965 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
1966 return;
1967 }
1968 }
1970 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1971 if (!is_external_suspend()) {
1972 // a racing resume has cancelled us; bail out now
1973 return;
1974 }
1976 // suspend is done
1977 uint32_t debug_bits = 0;
1978 // Warning: is_ext_suspend_completed() may temporarily drop the
1979 // SR_lock to allow the thread to reach a stable thread state if
1980 // it is currently in a transient thread state.
1981 if (is_ext_suspend_completed(false /* !called_by_wait */,
1982 SuspendRetryDelay, &debug_bits) ) {
1983 return;
1984 }
1985 }
1987 VM_ForceSafepoint vm_suspend;
1988 VMThread::execute(&vm_suspend);
1989 }
1991 // Part II of external suspension.
1992 // A JavaThread self suspends when it detects a pending external suspend
1993 // request. This is usually on transitions. It is also done in places
1994 // where continuing to the next transition would surprise the caller,
1995 // e.g., monitor entry.
1996 //
1997 // Returns the number of times that the thread self-suspended.
1998 //
1999 // Note: DO NOT call java_suspend_self() when you just want to block current
2000 // thread. java_suspend_self() is the second stage of cooperative
2001 // suspension for external suspend requests and should only be used
2002 // to complete an external suspend request.
2003 //
2004 int JavaThread::java_suspend_self() {
2005 int ret = 0;
2007 // we are in the process of exiting so don't suspend
2008 if (is_exiting()) {
2009 clear_external_suspend();
2010 return ret;
2011 }
2013 assert(_anchor.walkable() ||
2014 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2015 "must have walkable stack");
2017 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2019 assert(!this->is_ext_suspended(),
2020 "a thread trying to self-suspend should not already be suspended");
2022 if (this->is_suspend_equivalent()) {
2023 // If we are self-suspending as a result of the lifting of a
2024 // suspend equivalent condition, then the suspend_equivalent
2025 // flag is not cleared until we set the ext_suspended flag so
2026 // that wait_for_ext_suspend_completion() returns consistent
2027 // results.
2028 this->clear_suspend_equivalent();
2029 }
2031 // A racing resume may have cancelled us before we grabbed SR_lock
2032 // above. Or another external suspend request could be waiting for us
2033 // by the time we return from SR_lock()->wait(). The thread
2034 // that requested the suspension may already be trying to walk our
2035 // stack and if we return now, we can change the stack out from under
2036 // it. This would be a "bad thing (TM)" and cause the stack walker
2037 // to crash. We stay self-suspended until there are no more pending
2038 // external suspend requests.
2039 while (is_external_suspend()) {
2040 ret++;
2041 this->set_ext_suspended();
2043 // _ext_suspended flag is cleared by java_resume()
2044 while (is_ext_suspended()) {
2045 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2046 }
2047 }
2049 return ret;
2050 }
2052 #ifdef ASSERT
2053 // verify the JavaThread has not yet been published in the Threads::list, and
2054 // hence doesn't need protection from concurrent access at this stage
2055 void JavaThread::verify_not_published() {
2056 if (!Threads_lock->owned_by_self()) {
2057 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2058 assert( !Threads::includes(this),
2059 "java thread shouldn't have been published yet!");
2060 }
2061 else {
2062 assert( !Threads::includes(this),
2063 "java thread shouldn't have been published yet!");
2064 }
2065 }
2066 #endif
2068 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2069 // progress or when _suspend_flags is non-zero.
2070 // Current thread needs to self-suspend if there is a suspend request and/or
2071 // block if a safepoint is in progress.
2072 // Async exception ISN'T checked.
2073 // Note only the ThreadInVMfromNative transition can call this function
2074 // directly and when thread state is _thread_in_native_trans
2075 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2076 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2078 JavaThread *curJT = JavaThread::current();
2079 bool do_self_suspend = thread->is_external_suspend();
2081 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2083 // If JNIEnv proxies are allowed, don't self-suspend if the target
2084 // thread is not the current thread. In older versions of jdbx, jdbx
2085 // threads could call into the VM with another thread's JNIEnv so we
2086 // can be here operating on behalf of a suspended thread (4432884).
2087 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2088 JavaThreadState state = thread->thread_state();
2090 // We mark this thread_blocked state as a suspend-equivalent so
2091 // that a caller to is_ext_suspend_completed() won't be confused.
2092 // The suspend-equivalent state is cleared by java_suspend_self().
2093 thread->set_suspend_equivalent();
2095 // If the safepoint code sees the _thread_in_native_trans state, it will
2096 // wait until the thread changes to other thread state. There is no
2097 // guarantee on how soon we can obtain the SR_lock and complete the
2098 // self-suspend request. It would be a bad idea to let safepoint wait for
2099 // too long. Temporarily change the state to _thread_blocked to
2100 // let the VM thread know that this thread is ready for GC. The problem
2101 // of changing thread state is that safepoint could happen just after
2102 // java_suspend_self() returns after being resumed, and VM thread will
2103 // see the _thread_blocked state. We must check for safepoint
2104 // after restoring the state and make sure we won't leave while a safepoint
2105 // is in progress.
2106 thread->set_thread_state(_thread_blocked);
2107 thread->java_suspend_self();
2108 thread->set_thread_state(state);
2109 // Make sure new state is seen by VM thread
2110 if (os::is_MP()) {
2111 if (UseMembar) {
2112 // Force a fence between the write above and read below
2113 OrderAccess::fence();
2114 } else {
2115 // Must use this rather than serialization page in particular on Windows
2116 InterfaceSupport::serialize_memory(thread);
2117 }
2118 }
2119 }
2121 if (SafepointSynchronize::do_call_back()) {
2122 // If we are safepointing, then block the caller which may not be
2123 // the same as the target thread (see above).
2124 SafepointSynchronize::block(curJT);
2125 }
2127 if (thread->is_deopt_suspend()) {
2128 thread->clear_deopt_suspend();
2129 RegisterMap map(thread, false);
2130 frame f = thread->last_frame();
2131 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2132 f = f.sender(&map);
2133 }
2134 if (f.id() == thread->must_deopt_id()) {
2135 thread->clear_must_deopt_id();
2136 f.deoptimize(thread);
2137 } else {
2138 fatal("missed deoptimization!");
2139 }
2140 }
2141 }
2143 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2144 // progress or when _suspend_flags is non-zero.
2145 // Current thread needs to self-suspend if there is a suspend request and/or
2146 // block if a safepoint is in progress.
2147 // Also check for pending async exception (not including unsafe access error).
2148 // Note only the native==>VM/Java barriers can call this function and when
2149 // thread state is _thread_in_native_trans.
2150 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2151 check_safepoint_and_suspend_for_native_trans(thread);
2153 if (thread->has_async_exception()) {
2154 // We are in _thread_in_native_trans state, don't handle unsafe
2155 // access error since that may block.
2156 thread->check_and_handle_async_exceptions(false);
2157 }
2158 }
2160 // We need to guarantee the Threads_lock here, since resumes are not
2161 // allowed during safepoint synchronization
2162 // Can only resume from an external suspension
2163 void JavaThread::java_resume() {
2164 assert_locked_or_safepoint(Threads_lock);
2166 // Sanity check: thread is gone, has started exiting or the thread
2167 // was not externally suspended.
2168 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2169 return;
2170 }
2172 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2174 clear_external_suspend();
2176 if (is_ext_suspended()) {
2177 clear_ext_suspended();
2178 SR_lock()->notify_all();
2179 }
2180 }
2182 void JavaThread::create_stack_guard_pages() {
2183 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2184 address low_addr = stack_base() - stack_size();
2185 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2187 int allocate = os::allocate_stack_guard_pages();
2188 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2190 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2191 warning("Attempt to allocate stack guard pages failed.");
2192 return;
2193 }
2195 if (os::guard_memory((char *) low_addr, len)) {
2196 _stack_guard_state = stack_guard_enabled;
2197 } else {
2198 warning("Attempt to protect stack guard pages failed.");
2199 if (os::uncommit_memory((char *) low_addr, len)) {
2200 warning("Attempt to deallocate stack guard pages failed.");
2201 }
2202 }
2203 }
2205 void JavaThread::remove_stack_guard_pages() {
2206 if (_stack_guard_state == stack_guard_unused) return;
2207 address low_addr = stack_base() - stack_size();
2208 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2210 if (os::allocate_stack_guard_pages()) {
2211 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2212 _stack_guard_state = stack_guard_unused;
2213 } else {
2214 warning("Attempt to deallocate stack guard pages failed.");
2215 }
2216 } else {
2217 if (_stack_guard_state == stack_guard_unused) return;
2218 if (os::unguard_memory((char *) low_addr, len)) {
2219 _stack_guard_state = stack_guard_unused;
2220 } else {
2221 warning("Attempt to unprotect stack guard pages failed.");
2222 }
2223 }
2224 }
2226 void JavaThread::enable_stack_yellow_zone() {
2227 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2228 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2230 // The base notation is from the stacks point of view, growing downward.
2231 // We need to adjust it to work correctly with guard_memory()
2232 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2234 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2235 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2237 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2238 _stack_guard_state = stack_guard_enabled;
2239 } else {
2240 warning("Attempt to guard stack yellow zone failed.");
2241 }
2242 enable_register_stack_guard();
2243 }
2245 void JavaThread::disable_stack_yellow_zone() {
2246 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2247 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2249 // Simply return if called for a thread that does not use guard pages.
2250 if (_stack_guard_state == stack_guard_unused) return;
2252 // The base notation is from the stacks point of view, growing downward.
2253 // We need to adjust it to work correctly with guard_memory()
2254 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2256 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2257 _stack_guard_state = stack_guard_yellow_disabled;
2258 } else {
2259 warning("Attempt to unguard stack yellow zone failed.");
2260 }
2261 disable_register_stack_guard();
2262 }
2264 void JavaThread::enable_stack_red_zone() {
2265 // The base notation is from the stacks point of view, growing downward.
2266 // We need to adjust it to work correctly with guard_memory()
2267 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2268 address base = stack_red_zone_base() - stack_red_zone_size();
2270 guarantee(base < stack_base(),"Error calculating stack red zone");
2271 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2273 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2274 warning("Attempt to guard stack red zone failed.");
2275 }
2276 }
2278 void JavaThread::disable_stack_red_zone() {
2279 // The base notation is from the stacks point of view, growing downward.
2280 // We need to adjust it to work correctly with guard_memory()
2281 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2282 address base = stack_red_zone_base() - stack_red_zone_size();
2283 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2284 warning("Attempt to unguard stack red zone failed.");
2285 }
2286 }
2288 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2289 // ignore is there is no stack
2290 if (!has_last_Java_frame()) return;
2291 // traverse the stack frames. Starts from top frame.
2292 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2293 frame* fr = fst.current();
2294 f(fr, fst.register_map());
2295 }
2296 }
2299 #ifndef PRODUCT
2300 // Deoptimization
2301 // Function for testing deoptimization
2302 void JavaThread::deoptimize() {
2303 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2304 StackFrameStream fst(this, UseBiasedLocking);
2305 bool deopt = false; // Dump stack only if a deopt actually happens.
2306 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2307 // Iterate over all frames in the thread and deoptimize
2308 for(; !fst.is_done(); fst.next()) {
2309 if(fst.current()->can_be_deoptimized()) {
2311 if (only_at) {
2312 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2313 // consists of comma or carriage return separated numbers so
2314 // search for the current bci in that string.
2315 address pc = fst.current()->pc();
2316 nmethod* nm = (nmethod*) fst.current()->cb();
2317 ScopeDesc* sd = nm->scope_desc_at( pc);
2318 char buffer[8];
2319 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2320 size_t len = strlen(buffer);
2321 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2322 while (found != NULL) {
2323 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2324 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2325 // Check that the bci found is bracketed by terminators.
2326 break;
2327 }
2328 found = strstr(found + 1, buffer);
2329 }
2330 if (!found) {
2331 continue;
2332 }
2333 }
2335 if (DebugDeoptimization && !deopt) {
2336 deopt = true; // One-time only print before deopt
2337 tty->print_cr("[BEFORE Deoptimization]");
2338 trace_frames();
2339 trace_stack();
2340 }
2341 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2342 }
2343 }
2345 if (DebugDeoptimization && deopt) {
2346 tty->print_cr("[AFTER Deoptimization]");
2347 trace_frames();
2348 }
2349 }
2352 // Make zombies
2353 void JavaThread::make_zombies() {
2354 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2355 if (fst.current()->can_be_deoptimized()) {
2356 // it is a Java nmethod
2357 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2358 nm->make_not_entrant();
2359 }
2360 }
2361 }
2362 #endif // PRODUCT
2365 void JavaThread::deoptimized_wrt_marked_nmethods() {
2366 if (!has_last_Java_frame()) return;
2367 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2368 StackFrameStream fst(this, UseBiasedLocking);
2369 for(; !fst.is_done(); fst.next()) {
2370 if (fst.current()->should_be_deoptimized()) {
2371 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2372 }
2373 }
2374 }
2377 // GC support
2378 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2380 void JavaThread::gc_epilogue() {
2381 frames_do(frame_gc_epilogue);
2382 }
2385 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2387 void JavaThread::gc_prologue() {
2388 frames_do(frame_gc_prologue);
2389 }
2391 // If the caller is a NamedThread, then remember, in the current scope,
2392 // the given JavaThread in its _processed_thread field.
2393 class RememberProcessedThread: public StackObj {
2394 NamedThread* _cur_thr;
2395 public:
2396 RememberProcessedThread(JavaThread* jthr) {
2397 Thread* thread = Thread::current();
2398 if (thread->is_Named_thread()) {
2399 _cur_thr = (NamedThread *)thread;
2400 _cur_thr->set_processed_thread(jthr);
2401 } else {
2402 _cur_thr = NULL;
2403 }
2404 }
2406 ~RememberProcessedThread() {
2407 if (_cur_thr) {
2408 _cur_thr->set_processed_thread(NULL);
2409 }
2410 }
2411 };
2413 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2414 // Verify that the deferred card marks have been flushed.
2415 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2417 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2418 // since there may be more than one thread using each ThreadProfiler.
2420 // Traverse the GCHandles
2421 Thread::oops_do(f, cf);
2423 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2424 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2426 if (has_last_Java_frame()) {
2427 // Record JavaThread to GC thread
2428 RememberProcessedThread rpt(this);
2430 // Traverse the privileged stack
2431 if (_privileged_stack_top != NULL) {
2432 _privileged_stack_top->oops_do(f);
2433 }
2435 // traverse the registered growable array
2436 if (_array_for_gc != NULL) {
2437 for (int index = 0; index < _array_for_gc->length(); index++) {
2438 f->do_oop(_array_for_gc->adr_at(index));
2439 }
2440 }
2442 // Traverse the monitor chunks
2443 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2444 chunk->oops_do(f);
2445 }
2447 // Traverse the execution stack
2448 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2449 fst.current()->oops_do(f, cf, fst.register_map());
2450 }
2451 }
2453 // callee_target is never live across a gc point so NULL it here should
2454 // it still contain a methdOop.
2456 set_callee_target(NULL);
2458 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2459 // If we have deferred set_locals there might be oops waiting to be
2460 // written
2461 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2462 if (list != NULL) {
2463 for (int i = 0; i < list->length(); i++) {
2464 list->at(i)->oops_do(f);
2465 }
2466 }
2468 // Traverse instance variables at the end since the GC may be moving things
2469 // around using this function
2470 f->do_oop((oop*) &_threadObj);
2471 f->do_oop((oop*) &_vm_result);
2472 f->do_oop((oop*) &_vm_result_2);
2473 f->do_oop((oop*) &_exception_oop);
2474 f->do_oop((oop*) &_pending_async_exception);
2476 if (jvmti_thread_state() != NULL) {
2477 jvmti_thread_state()->oops_do(f);
2478 }
2479 }
2481 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2482 Thread::nmethods_do(cf); // (super method is a no-op)
2484 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2485 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2487 if (has_last_Java_frame()) {
2488 // Traverse the execution stack
2489 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2490 fst.current()->nmethods_do(cf);
2491 }
2492 }
2493 }
2495 // Printing
2496 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2497 switch (_thread_state) {
2498 case _thread_uninitialized: return "_thread_uninitialized";
2499 case _thread_new: return "_thread_new";
2500 case _thread_new_trans: return "_thread_new_trans";
2501 case _thread_in_native: return "_thread_in_native";
2502 case _thread_in_native_trans: return "_thread_in_native_trans";
2503 case _thread_in_vm: return "_thread_in_vm";
2504 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2505 case _thread_in_Java: return "_thread_in_Java";
2506 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2507 case _thread_blocked: return "_thread_blocked";
2508 case _thread_blocked_trans: return "_thread_blocked_trans";
2509 default: return "unknown thread state";
2510 }
2511 }
2513 #ifndef PRODUCT
2514 void JavaThread::print_thread_state_on(outputStream *st) const {
2515 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2516 };
2517 void JavaThread::print_thread_state() const {
2518 print_thread_state_on(tty);
2519 };
2520 #endif // PRODUCT
2522 // Called by Threads::print() for VM_PrintThreads operation
2523 void JavaThread::print_on(outputStream *st) const {
2524 st->print("\"%s\" ", get_thread_name());
2525 oop thread_oop = threadObj();
2526 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2527 Thread::print_on(st);
2528 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2529 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2530 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2531 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2532 }
2533 #ifndef PRODUCT
2534 print_thread_state_on(st);
2535 _safepoint_state->print_on(st);
2536 #endif // PRODUCT
2537 }
2539 // Called by fatal error handler. The difference between this and
2540 // JavaThread::print() is that we can't grab lock or allocate memory.
2541 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2542 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2543 oop thread_obj = threadObj();
2544 if (thread_obj != NULL) {
2545 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2546 }
2547 st->print(" [");
2548 st->print("%s", _get_thread_state_name(_thread_state));
2549 if (osthread()) {
2550 st->print(", id=%d", osthread()->thread_id());
2551 }
2552 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2553 _stack_base - _stack_size, _stack_base);
2554 st->print("]");
2555 return;
2556 }
2558 // Verification
2560 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2562 void JavaThread::verify() {
2563 // Verify oops in the thread.
2564 oops_do(&VerifyOopClosure::verify_oop, NULL);
2566 // Verify the stack frames.
2567 frames_do(frame_verify);
2568 }
2570 // CR 6300358 (sub-CR 2137150)
2571 // Most callers of this method assume that it can't return NULL but a
2572 // thread may not have a name whilst it is in the process of attaching to
2573 // the VM - see CR 6412693, and there are places where a JavaThread can be
2574 // seen prior to having it's threadObj set (eg JNI attaching threads and
2575 // if vm exit occurs during initialization). These cases can all be accounted
2576 // for such that this method never returns NULL.
2577 const char* JavaThread::get_thread_name() const {
2578 #ifdef ASSERT
2579 // early safepoints can hit while current thread does not yet have TLS
2580 if (!SafepointSynchronize::is_at_safepoint()) {
2581 Thread *cur = Thread::current();
2582 if (!(cur->is_Java_thread() && cur == this)) {
2583 // Current JavaThreads are allowed to get their own name without
2584 // the Threads_lock.
2585 assert_locked_or_safepoint(Threads_lock);
2586 }
2587 }
2588 #endif // ASSERT
2589 return get_thread_name_string();
2590 }
2592 // Returns a non-NULL representation of this thread's name, or a suitable
2593 // descriptive string if there is no set name
2594 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2595 const char* name_str;
2596 oop thread_obj = threadObj();
2597 if (thread_obj != NULL) {
2598 typeArrayOop name = java_lang_Thread::name(thread_obj);
2599 if (name != NULL) {
2600 if (buf == NULL) {
2601 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2602 }
2603 else {
2604 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2605 }
2606 }
2607 else if (is_attaching()) { // workaround for 6412693 - see 6404306
2608 name_str = "<no-name - thread is attaching>";
2609 }
2610 else {
2611 name_str = Thread::name();
2612 }
2613 }
2614 else {
2615 name_str = Thread::name();
2616 }
2617 assert(name_str != NULL, "unexpected NULL thread name");
2618 return name_str;
2619 }
2622 const char* JavaThread::get_threadgroup_name() const {
2623 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2624 oop thread_obj = threadObj();
2625 if (thread_obj != NULL) {
2626 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2627 if (thread_group != NULL) {
2628 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2629 // ThreadGroup.name can be null
2630 if (name != NULL) {
2631 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2632 return str;
2633 }
2634 }
2635 }
2636 return NULL;
2637 }
2639 const char* JavaThread::get_parent_name() const {
2640 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2641 oop thread_obj = threadObj();
2642 if (thread_obj != NULL) {
2643 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2644 if (thread_group != NULL) {
2645 oop parent = java_lang_ThreadGroup::parent(thread_group);
2646 if (parent != NULL) {
2647 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2648 // ThreadGroup.name can be null
2649 if (name != NULL) {
2650 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2651 return str;
2652 }
2653 }
2654 }
2655 }
2656 return NULL;
2657 }
2659 ThreadPriority JavaThread::java_priority() const {
2660 oop thr_oop = threadObj();
2661 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2662 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2663 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2664 return priority;
2665 }
2667 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2669 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2670 // Link Java Thread object <-> C++ Thread
2672 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2673 // and put it into a new Handle. The Handle "thread_oop" can then
2674 // be used to pass the C++ thread object to other methods.
2676 // Set the Java level thread object (jthread) field of the
2677 // new thread (a JavaThread *) to C++ thread object using the
2678 // "thread_oop" handle.
2680 // Set the thread field (a JavaThread *) of the
2681 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2683 Handle thread_oop(Thread::current(),
2684 JNIHandles::resolve_non_null(jni_thread));
2685 assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
2686 "must be initialized");
2687 set_threadObj(thread_oop());
2688 java_lang_Thread::set_thread(thread_oop(), this);
2690 if (prio == NoPriority) {
2691 prio = java_lang_Thread::priority(thread_oop());
2692 assert(prio != NoPriority, "A valid priority should be present");
2693 }
2695 // Push the Java priority down to the native thread; needs Threads_lock
2696 Thread::set_priority(this, prio);
2698 // Add the new thread to the Threads list and set it in motion.
2699 // We must have threads lock in order to call Threads::add.
2700 // It is crucial that we do not block before the thread is
2701 // added to the Threads list for if a GC happens, then the java_thread oop
2702 // will not be visited by GC.
2703 Threads::add(this);
2704 }
2706 oop JavaThread::current_park_blocker() {
2707 // Support for JSR-166 locks
2708 oop thread_oop = threadObj();
2709 if (thread_oop != NULL &&
2710 JDK_Version::current().supports_thread_park_blocker()) {
2711 return java_lang_Thread::park_blocker(thread_oop);
2712 }
2713 return NULL;
2714 }
2717 void JavaThread::print_stack_on(outputStream* st) {
2718 if (!has_last_Java_frame()) return;
2719 ResourceMark rm;
2720 HandleMark hm;
2722 RegisterMap reg_map(this);
2723 vframe* start_vf = last_java_vframe(®_map);
2724 int count = 0;
2725 for (vframe* f = start_vf; f; f = f->sender() ) {
2726 if (f->is_java_frame()) {
2727 javaVFrame* jvf = javaVFrame::cast(f);
2728 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2730 // Print out lock information
2731 if (JavaMonitorsInStackTrace) {
2732 jvf->print_lock_info_on(st, count);
2733 }
2734 } else {
2735 // Ignore non-Java frames
2736 }
2738 // Bail-out case for too deep stacks
2739 count++;
2740 if (MaxJavaStackTraceDepth == count) return;
2741 }
2742 }
2745 // JVMTI PopFrame support
2746 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2747 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2748 if (in_bytes(size_in_bytes) != 0) {
2749 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes));
2750 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2751 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2752 }
2753 }
2755 void* JavaThread::popframe_preserved_args() {
2756 return _popframe_preserved_args;
2757 }
2759 ByteSize JavaThread::popframe_preserved_args_size() {
2760 return in_ByteSize(_popframe_preserved_args_size);
2761 }
2763 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2764 int sz = in_bytes(popframe_preserved_args_size());
2765 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2766 return in_WordSize(sz / wordSize);
2767 }
2769 void JavaThread::popframe_free_preserved_args() {
2770 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2771 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
2772 _popframe_preserved_args = NULL;
2773 _popframe_preserved_args_size = 0;
2774 }
2776 #ifndef PRODUCT
2778 void JavaThread::trace_frames() {
2779 tty->print_cr("[Describe stack]");
2780 int frame_no = 1;
2781 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2782 tty->print(" %d. ", frame_no++);
2783 fst.current()->print_value_on(tty,this);
2784 tty->cr();
2785 }
2786 }
2789 void JavaThread::trace_stack_from(vframe* start_vf) {
2790 ResourceMark rm;
2791 int vframe_no = 1;
2792 for (vframe* f = start_vf; f; f = f->sender() ) {
2793 if (f->is_java_frame()) {
2794 javaVFrame::cast(f)->print_activation(vframe_no++);
2795 } else {
2796 f->print();
2797 }
2798 if (vframe_no > StackPrintLimit) {
2799 tty->print_cr("...<more frames>...");
2800 return;
2801 }
2802 }
2803 }
2806 void JavaThread::trace_stack() {
2807 if (!has_last_Java_frame()) return;
2808 ResourceMark rm;
2809 HandleMark hm;
2810 RegisterMap reg_map(this);
2811 trace_stack_from(last_java_vframe(®_map));
2812 }
2815 #endif // PRODUCT
2818 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2819 assert(reg_map != NULL, "a map must be given");
2820 frame f = last_frame();
2821 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
2822 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2823 }
2824 return NULL;
2825 }
2828 klassOop JavaThread::security_get_caller_class(int depth) {
2829 vframeStream vfst(this);
2830 vfst.security_get_caller_frame(depth);
2831 if (!vfst.at_end()) {
2832 return vfst.method()->method_holder();
2833 }
2834 return NULL;
2835 }
2837 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
2838 assert(thread->is_Compiler_thread(), "must be compiler thread");
2839 CompileBroker::compiler_thread_loop();
2840 }
2842 // Create a CompilerThread
2843 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
2844 : JavaThread(&compiler_thread_entry) {
2845 _env = NULL;
2846 _log = NULL;
2847 _task = NULL;
2848 _queue = queue;
2849 _counters = counters;
2850 _buffer_blob = NULL;
2852 #ifndef PRODUCT
2853 _ideal_graph_printer = NULL;
2854 #endif
2855 }
2858 // ======= Threads ========
2860 // The Threads class links together all active threads, and provides
2861 // operations over all threads. It is protected by its own Mutex
2862 // lock, which is also used in other contexts to protect thread
2863 // operations from having the thread being operated on from exiting
2864 // and going away unexpectedly (e.g., safepoint synchronization)
2866 JavaThread* Threads::_thread_list = NULL;
2867 int Threads::_number_of_threads = 0;
2868 int Threads::_number_of_non_daemon_threads = 0;
2869 int Threads::_return_code = 0;
2870 size_t JavaThread::_stack_size_at_create = 0;
2872 // All JavaThreads
2873 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
2875 void os_stream();
2877 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
2878 void Threads::threads_do(ThreadClosure* tc) {
2879 assert_locked_or_safepoint(Threads_lock);
2880 // ALL_JAVA_THREADS iterates through all JavaThreads
2881 ALL_JAVA_THREADS(p) {
2882 tc->do_thread(p);
2883 }
2884 // Someday we could have a table or list of all non-JavaThreads.
2885 // For now, just manually iterate through them.
2886 tc->do_thread(VMThread::vm_thread());
2887 Universe::heap()->gc_threads_do(tc);
2888 WatcherThread *wt = WatcherThread::watcher_thread();
2889 // Strictly speaking, the following NULL check isn't sufficient to make sure
2890 // the data for WatcherThread is still valid upon being examined. However,
2891 // considering that WatchThread terminates when the VM is on the way to
2892 // exit at safepoint, the chance of the above is extremely small. The right
2893 // way to prevent termination of WatcherThread would be to acquire
2894 // Terminator_lock, but we can't do that without violating the lock rank
2895 // checking in some cases.
2896 if (wt != NULL)
2897 tc->do_thread(wt);
2899 // If CompilerThreads ever become non-JavaThreads, add them here
2900 }
2902 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
2904 extern void JDK_Version_init();
2906 // Check version
2907 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
2909 // Initialize the output stream module
2910 ostream_init();
2912 // Process java launcher properties.
2913 Arguments::process_sun_java_launcher_properties(args);
2915 // Initialize the os module before using TLS
2916 os::init();
2918 // Initialize system properties.
2919 Arguments::init_system_properties();
2921 // So that JDK version can be used as a discrimintor when parsing arguments
2922 JDK_Version_init();
2924 // Update/Initialize System properties after JDK version number is known
2925 Arguments::init_version_specific_system_properties();
2927 // Parse arguments
2928 jint parse_result = Arguments::parse(args);
2929 if (parse_result != JNI_OK) return parse_result;
2931 if (PauseAtStartup) {
2932 os::pause();
2933 }
2935 HS_DTRACE_PROBE(hotspot, vm__init__begin);
2937 // Record VM creation timing statistics
2938 TraceVmCreationTime create_vm_timer;
2939 create_vm_timer.start();
2941 // Timing (must come after argument parsing)
2942 TraceTime timer("Create VM", TraceStartupTime);
2944 // Initialize the os module after parsing the args
2945 jint os_init_2_result = os::init_2();
2946 if (os_init_2_result != JNI_OK) return os_init_2_result;
2948 // Initialize output stream logging
2949 ostream_init_log();
2951 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
2952 // Must be before create_vm_init_agents()
2953 if (Arguments::init_libraries_at_startup()) {
2954 convert_vm_init_libraries_to_agents();
2955 }
2957 // Launch -agentlib/-agentpath and converted -Xrun agents
2958 if (Arguments::init_agents_at_startup()) {
2959 create_vm_init_agents();
2960 }
2962 // Initialize Threads state
2963 _thread_list = NULL;
2964 _number_of_threads = 0;
2965 _number_of_non_daemon_threads = 0;
2967 // Initialize TLS
2968 ThreadLocalStorage::init();
2970 // Initialize global data structures and create system classes in heap
2971 vm_init_globals();
2973 // Attach the main thread to this os thread
2974 JavaThread* main_thread = new JavaThread();
2975 main_thread->set_thread_state(_thread_in_vm);
2976 // must do this before set_active_handles and initialize_thread_local_storage
2977 // Note: on solaris initialize_thread_local_storage() will (indirectly)
2978 // change the stack size recorded here to one based on the java thread
2979 // stacksize. This adjusted size is what is used to figure the placement
2980 // of the guard pages.
2981 main_thread->record_stack_base_and_size();
2982 main_thread->initialize_thread_local_storage();
2984 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
2986 if (!main_thread->set_as_starting_thread()) {
2987 vm_shutdown_during_initialization(
2988 "Failed necessary internal allocation. Out of swap space");
2989 delete main_thread;
2990 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2991 return JNI_ENOMEM;
2992 }
2994 // Enable guard page *after* os::create_main_thread(), otherwise it would
2995 // crash Linux VM, see notes in os_linux.cpp.
2996 main_thread->create_stack_guard_pages();
2998 // Initialize Java-Level synchronization subsystem
2999 ObjectMonitor::Initialize() ;
3001 // Initialize global modules
3002 jint status = init_globals();
3003 if (status != JNI_OK) {
3004 delete main_thread;
3005 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3006 return status;
3007 }
3009 // Should be done after the heap is fully created
3010 main_thread->cache_global_variables();
3012 HandleMark hm;
3014 { MutexLocker mu(Threads_lock);
3015 Threads::add(main_thread);
3016 }
3018 // Any JVMTI raw monitors entered in onload will transition into
3019 // real raw monitor. VM is setup enough here for raw monitor enter.
3020 JvmtiExport::transition_pending_onload_raw_monitors();
3022 if (VerifyBeforeGC &&
3023 Universe::heap()->total_collections() >= VerifyGCStartAt) {
3024 Universe::heap()->prepare_for_verify();
3025 Universe::verify(); // make sure we're starting with a clean slate
3026 }
3028 // Create the VMThread
3029 { TraceTime timer("Start VMThread", TraceStartupTime);
3030 VMThread::create();
3031 Thread* vmthread = VMThread::vm_thread();
3033 if (!os::create_thread(vmthread, os::vm_thread))
3034 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3036 // Wait for the VM thread to become ready, and VMThread::run to initialize
3037 // Monitors can have spurious returns, must always check another state flag
3038 {
3039 MutexLocker ml(Notify_lock);
3040 os::start_thread(vmthread);
3041 while (vmthread->active_handles() == NULL) {
3042 Notify_lock->wait();
3043 }
3044 }
3045 }
3047 assert (Universe::is_fully_initialized(), "not initialized");
3048 EXCEPTION_MARK;
3050 // At this point, the Universe is initialized, but we have not executed
3051 // any byte code. Now is a good time (the only time) to dump out the
3052 // internal state of the JVM for sharing.
3054 if (DumpSharedSpaces) {
3055 Universe::heap()->preload_and_dump(CHECK_0);
3056 ShouldNotReachHere();
3057 }
3059 // Always call even when there are not JVMTI environments yet, since environments
3060 // may be attached late and JVMTI must track phases of VM execution
3061 JvmtiExport::enter_start_phase();
3063 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3064 JvmtiExport::post_vm_start();
3066 {
3067 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3069 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3070 create_vm_init_libraries();
3071 }
3073 if (InitializeJavaLangString) {
3074 initialize_class(vmSymbolHandles::java_lang_String(), CHECK_0);
3075 } else {
3076 warning("java.lang.String not initialized");
3077 }
3079 if (AggressiveOpts) {
3080 {
3081 // Forcibly initialize java/util/HashMap and mutate the private
3082 // static final "frontCacheEnabled" field before we start creating instances
3083 #ifdef ASSERT
3084 klassOop tmp_k = SystemDictionary::find(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3085 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
3086 #endif
3087 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3088 KlassHandle k = KlassHandle(THREAD, k_o);
3089 guarantee(k.not_null(), "Must find java/util/HashMap");
3090 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3091 ik->initialize(CHECK_0);
3092 fieldDescriptor fd;
3093 // Possible we might not find this field; if so, don't break
3094 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3095 k()->bool_field_put(fd.offset(), true);
3096 }
3097 }
3099 if (UseStringCache) {
3100 // Forcibly initialize java/lang/StringValue and mutate the private
3101 // static final "stringCacheEnabled" field before we start creating instances
3102 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3103 // Possible that StringValue isn't present: if so, silently don't break
3104 if (k_o != NULL) {
3105 KlassHandle k = KlassHandle(THREAD, k_o);
3106 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3107 ik->initialize(CHECK_0);
3108 fieldDescriptor fd;
3109 // Possible we might not find this field: if so, silently don't break
3110 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3111 k()->bool_field_put(fd.offset(), true);
3112 }
3113 }
3114 }
3115 }
3117 // Initialize java_lang.System (needed before creating the thread)
3118 if (InitializeJavaLangSystem) {
3119 initialize_class(vmSymbolHandles::java_lang_System(), CHECK_0);
3120 initialize_class(vmSymbolHandles::java_lang_ThreadGroup(), CHECK_0);
3121 Handle thread_group = create_initial_thread_group(CHECK_0);
3122 Universe::set_main_thread_group(thread_group());
3123 initialize_class(vmSymbolHandles::java_lang_Thread(), CHECK_0);
3124 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3125 main_thread->set_threadObj(thread_object);
3126 // Set thread status to running since main thread has
3127 // been started and running.
3128 java_lang_Thread::set_thread_status(thread_object,
3129 java_lang_Thread::RUNNABLE);
3131 // The VM preresolve methods to these classes. Make sure that get initialized
3132 initialize_class(vmSymbolHandles::java_lang_reflect_Method(), CHECK_0);
3133 initialize_class(vmSymbolHandles::java_lang_ref_Finalizer(), CHECK_0);
3134 // The VM creates & returns objects of this class. Make sure it's initialized.
3135 initialize_class(vmSymbolHandles::java_lang_Class(), CHECK_0);
3136 call_initializeSystemClass(CHECK_0);
3137 } else {
3138 warning("java.lang.System not initialized");
3139 }
3141 // an instance of OutOfMemory exception has been allocated earlier
3142 if (InitializeJavaLangExceptionsErrors) {
3143 initialize_class(vmSymbolHandles::java_lang_OutOfMemoryError(), CHECK_0);
3144 initialize_class(vmSymbolHandles::java_lang_NullPointerException(), CHECK_0);
3145 initialize_class(vmSymbolHandles::java_lang_ClassCastException(), CHECK_0);
3146 initialize_class(vmSymbolHandles::java_lang_ArrayStoreException(), CHECK_0);
3147 initialize_class(vmSymbolHandles::java_lang_ArithmeticException(), CHECK_0);
3148 initialize_class(vmSymbolHandles::java_lang_StackOverflowError(), CHECK_0);
3149 initialize_class(vmSymbolHandles::java_lang_IllegalMonitorStateException(), CHECK_0);
3150 } else {
3151 warning("java.lang.OutOfMemoryError has not been initialized");
3152 warning("java.lang.NullPointerException has not been initialized");
3153 warning("java.lang.ClassCastException has not been initialized");
3154 warning("java.lang.ArrayStoreException has not been initialized");
3155 warning("java.lang.ArithmeticException has not been initialized");
3156 warning("java.lang.StackOverflowError has not been initialized");
3157 }
3159 if (EnableInvokeDynamic) {
3160 // JSR 292: An intialized java.dyn.InvokeDynamic is required in
3161 // the compiler.
3162 initialize_class(vmSymbolHandles::java_dyn_InvokeDynamic(), CHECK_0);
3163 }
3164 }
3166 // See : bugid 4211085.
3167 // Background : the static initializer of java.lang.Compiler tries to read
3168 // property"java.compiler" and read & write property "java.vm.info".
3169 // When a security manager is installed through the command line
3170 // option "-Djava.security.manager", the above properties are not
3171 // readable and the static initializer for java.lang.Compiler fails
3172 // resulting in a NoClassDefFoundError. This can happen in any
3173 // user code which calls methods in java.lang.Compiler.
3174 // Hack : the hack is to pre-load and initialize this class, so that only
3175 // system domains are on the stack when the properties are read.
3176 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3177 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3178 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3179 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3180 // Once that is done, we should remove this hack.
3181 initialize_class(vmSymbolHandles::java_lang_Compiler(), CHECK_0);
3183 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3184 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3185 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3186 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3187 // This should also be taken out as soon as 4211383 gets fixed.
3188 reset_vm_info_property(CHECK_0);
3190 quicken_jni_functions();
3192 // Set flag that basic initialization has completed. Used by exceptions and various
3193 // debug stuff, that does not work until all basic classes have been initialized.
3194 set_init_completed();
3196 HS_DTRACE_PROBE(hotspot, vm__init__end);
3198 // record VM initialization completion time
3199 Management::record_vm_init_completed();
3201 // Compute system loader. Note that this has to occur after set_init_completed, since
3202 // valid exceptions may be thrown in the process.
3203 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3204 // set_init_completed has just been called, causing exceptions not to be shortcut
3205 // anymore. We call vm_exit_during_initialization directly instead.
3206 SystemDictionary::compute_java_system_loader(THREAD);
3207 if (HAS_PENDING_EXCEPTION) {
3208 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3209 }
3211 #ifdef KERNEL
3212 if (JDK_Version::is_gte_jdk17x_version()) {
3213 set_jkernel_boot_classloader_hook(THREAD);
3214 }
3215 #endif // KERNEL
3217 #ifndef SERIALGC
3218 // Support for ConcurrentMarkSweep. This should be cleaned up
3219 // and better encapsulated. The ugly nested if test would go away
3220 // once things are properly refactored. XXX YSR
3221 if (UseConcMarkSweepGC || UseG1GC) {
3222 if (UseConcMarkSweepGC) {
3223 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3224 } else {
3225 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3226 }
3227 if (HAS_PENDING_EXCEPTION) {
3228 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3229 }
3230 }
3231 #endif // SERIALGC
3233 // Always call even when there are not JVMTI environments yet, since environments
3234 // may be attached late and JVMTI must track phases of VM execution
3235 JvmtiExport::enter_live_phase();
3237 // Signal Dispatcher needs to be started before VMInit event is posted
3238 os::signal_init();
3240 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3241 if (!DisableAttachMechanism) {
3242 if (StartAttachListener || AttachListener::init_at_startup()) {
3243 AttachListener::init();
3244 }
3245 }
3247 // Launch -Xrun agents
3248 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3249 // back-end can launch with -Xdebug -Xrunjdwp.
3250 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3251 create_vm_init_libraries();
3252 }
3254 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3255 JvmtiExport::post_vm_initialized();
3257 Chunk::start_chunk_pool_cleaner_task();
3259 // initialize compiler(s)
3260 CompileBroker::compilation_init();
3262 Management::initialize(THREAD);
3263 if (HAS_PENDING_EXCEPTION) {
3264 // management agent fails to start possibly due to
3265 // configuration problem and is responsible for printing
3266 // stack trace if appropriate. Simply exit VM.
3267 vm_exit(1);
3268 }
3270 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3271 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3272 if (MemProfiling) MemProfiler::engage();
3273 StatSampler::engage();
3274 if (CheckJNICalls) JniPeriodicChecker::engage();
3276 BiasedLocking::init();
3279 // Start up the WatcherThread if there are any periodic tasks
3280 // NOTE: All PeriodicTasks should be registered by now. If they
3281 // aren't, late joiners might appear to start slowly (we might
3282 // take a while to process their first tick).
3283 if (PeriodicTask::num_tasks() > 0) {
3284 WatcherThread::start();
3285 }
3287 // Give os specific code one last chance to start
3288 os::init_3();
3290 create_vm_timer.end();
3291 return JNI_OK;
3292 }
3294 // type for the Agent_OnLoad and JVM_OnLoad entry points
3295 extern "C" {
3296 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3297 }
3298 // Find a command line agent library and return its entry point for
3299 // -agentlib: -agentpath: -Xrun
3300 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3301 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3302 OnLoadEntry_t on_load_entry = NULL;
3303 void *library = agent->os_lib(); // check if we have looked it up before
3305 if (library == NULL) {
3306 char buffer[JVM_MAXPATHLEN];
3307 char ebuf[1024];
3308 const char *name = agent->name();
3309 const char *msg = "Could not find agent library ";
3311 if (agent->is_absolute_path()) {
3312 library = hpi::dll_load(name, ebuf, sizeof ebuf);
3313 if (library == NULL) {
3314 const char *sub_msg = " in absolute path, with error: ";
3315 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3316 char *buf = NEW_C_HEAP_ARRAY(char, len);
3317 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3318 // If we can't find the agent, exit.
3319 vm_exit_during_initialization(buf, NULL);
3320 FREE_C_HEAP_ARRAY(char, buf);
3321 }
3322 } else {
3323 // Try to load the agent from the standard dll directory
3324 hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
3325 library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3326 #ifdef KERNEL
3327 // Download instrument dll
3328 if (library == NULL && strcmp(name, "instrument") == 0) {
3329 char *props = Arguments::get_kernel_properties();
3330 char *home = Arguments::get_java_home();
3331 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false"
3332 " sun.jkernel.DownloadManager -download client_jvm";
3333 size_t length = strlen(props) + strlen(home) + strlen(fmt) + 1;
3334 char *cmd = NEW_C_HEAP_ARRAY(char, length);
3335 jio_snprintf(cmd, length, fmt, home, props);
3336 int status = os::fork_and_exec(cmd);
3337 FreeHeap(props);
3338 if (status == -1) {
3339 warning(cmd);
3340 vm_exit_during_initialization("fork_and_exec failed: %s",
3341 strerror(errno));
3342 }
3343 FREE_C_HEAP_ARRAY(char, cmd);
3344 // when this comes back the instrument.dll should be where it belongs.
3345 library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3346 }
3347 #endif // KERNEL
3348 if (library == NULL) { // Try the local directory
3349 char ns[1] = {0};
3350 hpi::dll_build_name(buffer, sizeof(buffer), ns, name);
3351 library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3352 if (library == NULL) {
3353 const char *sub_msg = " on the library path, with error: ";
3354 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3355 char *buf = NEW_C_HEAP_ARRAY(char, len);
3356 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3357 // If we can't find the agent, exit.
3358 vm_exit_during_initialization(buf, NULL);
3359 FREE_C_HEAP_ARRAY(char, buf);
3360 }
3361 }
3362 }
3363 agent->set_os_lib(library);
3364 }
3366 // Find the OnLoad function.
3367 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3368 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, hpi::dll_lookup(library, on_load_symbols[symbol_index]));
3369 if (on_load_entry != NULL) break;
3370 }
3371 return on_load_entry;
3372 }
3374 // Find the JVM_OnLoad entry point
3375 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3376 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3377 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3378 }
3380 // Find the Agent_OnLoad entry point
3381 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3382 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3383 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3384 }
3386 // For backwards compatibility with -Xrun
3387 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3388 // treated like -agentpath:
3389 // Must be called before agent libraries are created
3390 void Threads::convert_vm_init_libraries_to_agents() {
3391 AgentLibrary* agent;
3392 AgentLibrary* next;
3394 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3395 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3396 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3398 // If there is an JVM_OnLoad function it will get called later,
3399 // otherwise see if there is an Agent_OnLoad
3400 if (on_load_entry == NULL) {
3401 on_load_entry = lookup_agent_on_load(agent);
3402 if (on_load_entry != NULL) {
3403 // switch it to the agent list -- so that Agent_OnLoad will be called,
3404 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3405 Arguments::convert_library_to_agent(agent);
3406 } else {
3407 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3408 }
3409 }
3410 }
3411 }
3413 // Create agents for -agentlib: -agentpath: and converted -Xrun
3414 // Invokes Agent_OnLoad
3415 // Called very early -- before JavaThreads exist
3416 void Threads::create_vm_init_agents() {
3417 extern struct JavaVM_ main_vm;
3418 AgentLibrary* agent;
3420 JvmtiExport::enter_onload_phase();
3421 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3422 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3424 if (on_load_entry != NULL) {
3425 // Invoke the Agent_OnLoad function
3426 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3427 if (err != JNI_OK) {
3428 vm_exit_during_initialization("agent library failed to init", agent->name());
3429 }
3430 } else {
3431 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3432 }
3433 }
3434 JvmtiExport::enter_primordial_phase();
3435 }
3437 extern "C" {
3438 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3439 }
3441 void Threads::shutdown_vm_agents() {
3442 // Send any Agent_OnUnload notifications
3443 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3444 extern struct JavaVM_ main_vm;
3445 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3447 // Find the Agent_OnUnload function.
3448 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3449 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3450 hpi::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3452 // Invoke the Agent_OnUnload function
3453 if (unload_entry != NULL) {
3454 JavaThread* thread = JavaThread::current();
3455 ThreadToNativeFromVM ttn(thread);
3456 HandleMark hm(thread);
3457 (*unload_entry)(&main_vm);
3458 break;
3459 }
3460 }
3461 }
3462 }
3464 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3465 // Invokes JVM_OnLoad
3466 void Threads::create_vm_init_libraries() {
3467 extern struct JavaVM_ main_vm;
3468 AgentLibrary* agent;
3470 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3471 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3473 if (on_load_entry != NULL) {
3474 // Invoke the JVM_OnLoad function
3475 JavaThread* thread = JavaThread::current();
3476 ThreadToNativeFromVM ttn(thread);
3477 HandleMark hm(thread);
3478 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3479 if (err != JNI_OK) {
3480 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3481 }
3482 } else {
3483 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3484 }
3485 }
3486 }
3488 // Last thread running calls java.lang.Shutdown.shutdown()
3489 void JavaThread::invoke_shutdown_hooks() {
3490 HandleMark hm(this);
3492 // We could get here with a pending exception, if so clear it now.
3493 if (this->has_pending_exception()) {
3494 this->clear_pending_exception();
3495 }
3497 EXCEPTION_MARK;
3498 klassOop k =
3499 SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_Shutdown(),
3500 THREAD);
3501 if (k != NULL) {
3502 // SystemDictionary::resolve_or_null will return null if there was
3503 // an exception. If we cannot load the Shutdown class, just don't
3504 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3505 // and finalizers (if runFinalizersOnExit is set) won't be run.
3506 // Note that if a shutdown hook was registered or runFinalizersOnExit
3507 // was called, the Shutdown class would have already been loaded
3508 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3509 instanceKlassHandle shutdown_klass (THREAD, k);
3510 JavaValue result(T_VOID);
3511 JavaCalls::call_static(&result,
3512 shutdown_klass,
3513 vmSymbolHandles::shutdown_method_name(),
3514 vmSymbolHandles::void_method_signature(),
3515 THREAD);
3516 }
3517 CLEAR_PENDING_EXCEPTION;
3518 }
3520 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3521 // the program falls off the end of main(). Another VM exit path is through
3522 // vm_exit() when the program calls System.exit() to return a value or when
3523 // there is a serious error in VM. The two shutdown paths are not exactly
3524 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3525 // and VM_Exit op at VM level.
3526 //
3527 // Shutdown sequence:
3528 // + Wait until we are the last non-daemon thread to execute
3529 // <-- every thing is still working at this moment -->
3530 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3531 // shutdown hooks, run finalizers if finalization-on-exit
3532 // + Call before_exit(), prepare for VM exit
3533 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3534 // currently the only user of this mechanism is File.deleteOnExit())
3535 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3536 // post thread end and vm death events to JVMTI,
3537 // stop signal thread
3538 // + Call JavaThread::exit(), it will:
3539 // > release JNI handle blocks, remove stack guard pages
3540 // > remove this thread from Threads list
3541 // <-- no more Java code from this thread after this point -->
3542 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3543 // the compiler threads at safepoint
3544 // <-- do not use anything that could get blocked by Safepoint -->
3545 // + Disable tracing at JNI/JVM barriers
3546 // + Set _vm_exited flag for threads that are still running native code
3547 // + Delete this thread
3548 // + Call exit_globals()
3549 // > deletes tty
3550 // > deletes PerfMemory resources
3551 // + Return to caller
3553 bool Threads::destroy_vm() {
3554 JavaThread* thread = JavaThread::current();
3556 // Wait until we are the last non-daemon thread to execute
3557 { MutexLocker nu(Threads_lock);
3558 while (Threads::number_of_non_daemon_threads() > 1 )
3559 // This wait should make safepoint checks, wait without a timeout,
3560 // and wait as a suspend-equivalent condition.
3561 //
3562 // Note: If the FlatProfiler is running and this thread is waiting
3563 // for another non-daemon thread to finish, then the FlatProfiler
3564 // is waiting for the external suspend request on this thread to
3565 // complete. wait_for_ext_suspend_completion() will eventually
3566 // timeout, but that takes time. Making this wait a suspend-
3567 // equivalent condition solves that timeout problem.
3568 //
3569 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3570 Mutex::_as_suspend_equivalent_flag);
3571 }
3573 // Hang forever on exit if we are reporting an error.
3574 if (ShowMessageBoxOnError && is_error_reported()) {
3575 os::infinite_sleep();
3576 }
3578 if (JDK_Version::is_jdk12x_version()) {
3579 // We are the last thread running, so check if finalizers should be run.
3580 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3581 HandleMark rm(thread);
3582 Universe::run_finalizers_on_exit();
3583 } else {
3584 // run Java level shutdown hooks
3585 thread->invoke_shutdown_hooks();
3586 }
3588 before_exit(thread);
3590 thread->exit(true);
3592 // Stop VM thread.
3593 {
3594 // 4945125 The vm thread comes to a safepoint during exit.
3595 // GC vm_operations can get caught at the safepoint, and the
3596 // heap is unparseable if they are caught. Grab the Heap_lock
3597 // to prevent this. The GC vm_operations will not be able to
3598 // queue until after the vm thread is dead.
3599 MutexLocker ml(Heap_lock);
3601 VMThread::wait_for_vm_thread_exit();
3602 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3603 VMThread::destroy();
3604 }
3606 // clean up ideal graph printers
3607 #if defined(COMPILER2) && !defined(PRODUCT)
3608 IdealGraphPrinter::clean_up();
3609 #endif
3611 // Now, all Java threads are gone except daemon threads. Daemon threads
3612 // running Java code or in VM are stopped by the Safepoint. However,
3613 // daemon threads executing native code are still running. But they
3614 // will be stopped at native=>Java/VM barriers. Note that we can't
3615 // simply kill or suspend them, as it is inherently deadlock-prone.
3617 #ifndef PRODUCT
3618 // disable function tracing at JNI/JVM barriers
3619 TraceHPI = false;
3620 TraceJNICalls = false;
3621 TraceJVMCalls = false;
3622 TraceRuntimeCalls = false;
3623 #endif
3625 VM_Exit::set_vm_exited();
3627 notify_vm_shutdown();
3629 delete thread;
3631 // exit_globals() will delete tty
3632 exit_globals();
3634 return true;
3635 }
3638 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3639 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3640 return is_supported_jni_version(version);
3641 }
3644 jboolean Threads::is_supported_jni_version(jint version) {
3645 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3646 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3647 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3648 return JNI_FALSE;
3649 }
3652 void Threads::add(JavaThread* p, bool force_daemon) {
3653 // The threads lock must be owned at this point
3654 assert_locked_or_safepoint(Threads_lock);
3656 // See the comment for this method in thread.hpp for its purpose and
3657 // why it is called here.
3658 p->initialize_queues();
3659 p->set_next(_thread_list);
3660 _thread_list = p;
3661 _number_of_threads++;
3662 oop threadObj = p->threadObj();
3663 bool daemon = true;
3664 // Bootstrapping problem: threadObj can be null for initial
3665 // JavaThread (or for threads attached via JNI)
3666 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3667 _number_of_non_daemon_threads++;
3668 daemon = false;
3669 }
3671 ThreadService::add_thread(p, daemon);
3673 // Possible GC point.
3674 Events::log("Thread added: " INTPTR_FORMAT, p);
3675 }
3677 void Threads::remove(JavaThread* p) {
3678 // Extra scope needed for Thread_lock, so we can check
3679 // that we do not remove thread without safepoint code notice
3680 { MutexLocker ml(Threads_lock);
3682 assert(includes(p), "p must be present");
3684 JavaThread* current = _thread_list;
3685 JavaThread* prev = NULL;
3687 while (current != p) {
3688 prev = current;
3689 current = current->next();
3690 }
3692 if (prev) {
3693 prev->set_next(current->next());
3694 } else {
3695 _thread_list = p->next();
3696 }
3697 _number_of_threads--;
3698 oop threadObj = p->threadObj();
3699 bool daemon = true;
3700 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
3701 _number_of_non_daemon_threads--;
3702 daemon = false;
3704 // Only one thread left, do a notify on the Threads_lock so a thread waiting
3705 // on destroy_vm will wake up.
3706 if (number_of_non_daemon_threads() == 1)
3707 Threads_lock->notify_all();
3708 }
3709 ThreadService::remove_thread(p, daemon);
3711 // Make sure that safepoint code disregard this thread. This is needed since
3712 // the thread might mess around with locks after this point. This can cause it
3713 // to do callbacks into the safepoint code. However, the safepoint code is not aware
3714 // of this thread since it is removed from the queue.
3715 p->set_terminated_value();
3716 } // unlock Threads_lock
3718 // Since Events::log uses a lock, we grab it outside the Threads_lock
3719 Events::log("Thread exited: " INTPTR_FORMAT, p);
3720 }
3722 // Threads_lock must be held when this is called (or must be called during a safepoint)
3723 bool Threads::includes(JavaThread* p) {
3724 assert(Threads_lock->is_locked(), "sanity check");
3725 ALL_JAVA_THREADS(q) {
3726 if (q == p ) {
3727 return true;
3728 }
3729 }
3730 return false;
3731 }
3733 // Operations on the Threads list for GC. These are not explicitly locked,
3734 // but the garbage collector must provide a safe context for them to run.
3735 // In particular, these things should never be called when the Threads_lock
3736 // is held by some other thread. (Note: the Safepoint abstraction also
3737 // uses the Threads_lock to gurantee this property. It also makes sure that
3738 // all threads gets blocked when exiting or starting).
3740 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3741 ALL_JAVA_THREADS(p) {
3742 p->oops_do(f, cf);
3743 }
3744 VMThread::vm_thread()->oops_do(f, cf);
3745 }
3747 void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) {
3748 // Introduce a mechanism allowing parallel threads to claim threads as
3749 // root groups. Overhead should be small enough to use all the time,
3750 // even in sequential code.
3751 SharedHeap* sh = SharedHeap::heap();
3752 bool is_par = (sh->n_par_threads() > 0);
3753 int cp = SharedHeap::heap()->strong_roots_parity();
3754 ALL_JAVA_THREADS(p) {
3755 if (p->claim_oops_do(is_par, cp)) {
3756 p->oops_do(f, cf);
3757 }
3758 }
3759 VMThread* vmt = VMThread::vm_thread();
3760 if (vmt->claim_oops_do(is_par, cp))
3761 vmt->oops_do(f, cf);
3762 }
3764 #ifndef SERIALGC
3765 // Used by ParallelScavenge
3766 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
3767 ALL_JAVA_THREADS(p) {
3768 q->enqueue(new ThreadRootsTask(p));
3769 }
3770 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
3771 }
3773 // Used by Parallel Old
3774 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
3775 ALL_JAVA_THREADS(p) {
3776 q->enqueue(new ThreadRootsMarkingTask(p));
3777 }
3778 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
3779 }
3780 #endif // SERIALGC
3782 void Threads::nmethods_do(CodeBlobClosure* cf) {
3783 ALL_JAVA_THREADS(p) {
3784 p->nmethods_do(cf);
3785 }
3786 VMThread::vm_thread()->nmethods_do(cf);
3787 }
3789 void Threads::gc_epilogue() {
3790 ALL_JAVA_THREADS(p) {
3791 p->gc_epilogue();
3792 }
3793 }
3795 void Threads::gc_prologue() {
3796 ALL_JAVA_THREADS(p) {
3797 p->gc_prologue();
3798 }
3799 }
3801 void Threads::deoptimized_wrt_marked_nmethods() {
3802 ALL_JAVA_THREADS(p) {
3803 p->deoptimized_wrt_marked_nmethods();
3804 }
3805 }
3808 // Get count Java threads that are waiting to enter the specified monitor.
3809 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
3810 address monitor, bool doLock) {
3811 assert(doLock || SafepointSynchronize::is_at_safepoint(),
3812 "must grab Threads_lock or be at safepoint");
3813 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3815 int i = 0;
3816 {
3817 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3818 ALL_JAVA_THREADS(p) {
3819 if (p->is_Compiler_thread()) continue;
3821 address pending = (address)p->current_pending_monitor();
3822 if (pending == monitor) { // found a match
3823 if (i < count) result->append(p); // save the first count matches
3824 i++;
3825 }
3826 }
3827 }
3828 return result;
3829 }
3832 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
3833 assert(doLock ||
3834 Threads_lock->owned_by_self() ||
3835 SafepointSynchronize::is_at_safepoint(),
3836 "must grab Threads_lock or be at safepoint");
3838 // NULL owner means not locked so we can skip the search
3839 if (owner == NULL) return NULL;
3841 {
3842 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3843 ALL_JAVA_THREADS(p) {
3844 // first, see if owner is the address of a Java thread
3845 if (owner == (address)p) return p;
3846 }
3847 }
3848 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
3849 if (UseHeavyMonitors) return NULL;
3851 //
3852 // If we didn't find a matching Java thread and we didn't force use of
3853 // heavyweight monitors, then the owner is the stack address of the
3854 // Lock Word in the owning Java thread's stack.
3855 //
3856 JavaThread* the_owner = NULL;
3857 {
3858 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3859 ALL_JAVA_THREADS(q) {
3860 if (q->is_lock_owned(owner)) {
3861 the_owner = q;
3862 break;
3863 }
3864 }
3865 }
3866 assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
3867 return the_owner;
3868 }
3870 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
3871 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
3872 char buf[32];
3873 st->print_cr(os::local_time_string(buf, sizeof(buf)));
3875 st->print_cr("Full thread dump %s (%s %s):",
3876 Abstract_VM_Version::vm_name(),
3877 Abstract_VM_Version::vm_release(),
3878 Abstract_VM_Version::vm_info_string()
3879 );
3880 st->cr();
3882 #ifndef SERIALGC
3883 // Dump concurrent locks
3884 ConcurrentLocksDump concurrent_locks;
3885 if (print_concurrent_locks) {
3886 concurrent_locks.dump_at_safepoint();
3887 }
3888 #endif // SERIALGC
3890 ALL_JAVA_THREADS(p) {
3891 ResourceMark rm;
3892 p->print_on(st);
3893 if (print_stacks) {
3894 if (internal_format) {
3895 p->trace_stack();
3896 } else {
3897 p->print_stack_on(st);
3898 }
3899 }
3900 st->cr();
3901 #ifndef SERIALGC
3902 if (print_concurrent_locks) {
3903 concurrent_locks.print_locks_on(p, st);
3904 }
3905 #endif // SERIALGC
3906 }
3908 VMThread::vm_thread()->print_on(st);
3909 st->cr();
3910 Universe::heap()->print_gc_threads_on(st);
3911 WatcherThread* wt = WatcherThread::watcher_thread();
3912 if (wt != NULL) wt->print_on(st);
3913 st->cr();
3914 CompileBroker::print_compiler_threads_on(st);
3915 st->flush();
3916 }
3918 // Threads::print_on_error() is called by fatal error handler. It's possible
3919 // that VM is not at safepoint and/or current thread is inside signal handler.
3920 // Don't print stack trace, as the stack may not be walkable. Don't allocate
3921 // memory (even in resource area), it might deadlock the error handler.
3922 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
3923 bool found_current = false;
3924 st->print_cr("Java Threads: ( => current thread )");
3925 ALL_JAVA_THREADS(thread) {
3926 bool is_current = (current == thread);
3927 found_current = found_current || is_current;
3929 st->print("%s", is_current ? "=>" : " ");
3931 st->print(PTR_FORMAT, thread);
3932 st->print(" ");
3933 thread->print_on_error(st, buf, buflen);
3934 st->cr();
3935 }
3936 st->cr();
3938 st->print_cr("Other Threads:");
3939 if (VMThread::vm_thread()) {
3940 bool is_current = (current == VMThread::vm_thread());
3941 found_current = found_current || is_current;
3942 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
3944 st->print(PTR_FORMAT, VMThread::vm_thread());
3945 st->print(" ");
3946 VMThread::vm_thread()->print_on_error(st, buf, buflen);
3947 st->cr();
3948 }
3949 WatcherThread* wt = WatcherThread::watcher_thread();
3950 if (wt != NULL) {
3951 bool is_current = (current == wt);
3952 found_current = found_current || is_current;
3953 st->print("%s", is_current ? "=>" : " ");
3955 st->print(PTR_FORMAT, wt);
3956 st->print(" ");
3957 wt->print_on_error(st, buf, buflen);
3958 st->cr();
3959 }
3960 if (!found_current) {
3961 st->cr();
3962 st->print("=>" PTR_FORMAT " (exited) ", current);
3963 current->print_on_error(st, buf, buflen);
3964 st->cr();
3965 }
3966 }
3968 // Internal SpinLock and Mutex
3969 // Based on ParkEvent
3971 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
3972 //
3973 // We employ SpinLocks _only for low-contention, fixed-length
3974 // short-duration critical sections where we're concerned
3975 // about native mutex_t or HotSpot Mutex:: latency.
3976 // The mux construct provides a spin-then-block mutual exclusion
3977 // mechanism.
3978 //
3979 // Testing has shown that contention on the ListLock guarding gFreeList
3980 // is common. If we implement ListLock as a simple SpinLock it's common
3981 // for the JVM to devolve to yielding with little progress. This is true
3982 // despite the fact that the critical sections protected by ListLock are
3983 // extremely short.
3984 //
3985 // TODO-FIXME: ListLock should be of type SpinLock.
3986 // We should make this a 1st-class type, integrated into the lock
3987 // hierarchy as leaf-locks. Critically, the SpinLock structure
3988 // should have sufficient padding to avoid false-sharing and excessive
3989 // cache-coherency traffic.
3992 typedef volatile int SpinLockT ;
3994 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
3995 if (Atomic::cmpxchg (1, adr, 0) == 0) {
3996 return ; // normal fast-path return
3997 }
3999 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4000 TEVENT (SpinAcquire - ctx) ;
4001 int ctr = 0 ;
4002 int Yields = 0 ;
4003 for (;;) {
4004 while (*adr != 0) {
4005 ++ctr ;
4006 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4007 if (Yields > 5) {
4008 // Consider using a simple NakedSleep() instead.
4009 // Then SpinAcquire could be called by non-JVM threads
4010 Thread::current()->_ParkEvent->park(1) ;
4011 } else {
4012 os::NakedYield() ;
4013 ++Yields ;
4014 }
4015 } else {
4016 SpinPause() ;
4017 }
4018 }
4019 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4020 }
4021 }
4023 void Thread::SpinRelease (volatile int * adr) {
4024 assert (*adr != 0, "invariant") ;
4025 OrderAccess::fence() ; // guarantee at least release consistency.
4026 // Roach-motel semantics.
4027 // It's safe if subsequent LDs and STs float "up" into the critical section,
4028 // but prior LDs and STs within the critical section can't be allowed
4029 // to reorder or float past the ST that releases the lock.
4030 *adr = 0 ;
4031 }
4033 // muxAcquire and muxRelease:
4034 //
4035 // * muxAcquire and muxRelease support a single-word lock-word construct.
4036 // The LSB of the word is set IFF the lock is held.
4037 // The remainder of the word points to the head of a singly-linked list
4038 // of threads blocked on the lock.
4039 //
4040 // * The current implementation of muxAcquire-muxRelease uses its own
4041 // dedicated Thread._MuxEvent instance. If we're interested in
4042 // minimizing the peak number of extant ParkEvent instances then
4043 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4044 // as certain invariants were satisfied. Specifically, care would need
4045 // to be taken with regards to consuming unpark() "permits".
4046 // A safe rule of thumb is that a thread would never call muxAcquire()
4047 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4048 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4049 // consume an unpark() permit intended for monitorenter, for instance.
4050 // One way around this would be to widen the restricted-range semaphore
4051 // implemented in park(). Another alternative would be to provide
4052 // multiple instances of the PlatformEvent() for each thread. One
4053 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4054 //
4055 // * Usage:
4056 // -- Only as leaf locks
4057 // -- for short-term locking only as muxAcquire does not perform
4058 // thread state transitions.
4059 //
4060 // Alternatives:
4061 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4062 // but with parking or spin-then-park instead of pure spinning.
4063 // * Use Taura-Oyama-Yonenzawa locks.
4064 // * It's possible to construct a 1-0 lock if we encode the lockword as
4065 // (List,LockByte). Acquire will CAS the full lockword while Release
4066 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4067 // acquiring threads use timers (ParkTimed) to detect and recover from
4068 // the stranding window. Thread/Node structures must be aligned on 256-byte
4069 // boundaries by using placement-new.
4070 // * Augment MCS with advisory back-link fields maintained with CAS().
4071 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4072 // The validity of the backlinks must be ratified before we trust the value.
4073 // If the backlinks are invalid the exiting thread must back-track through the
4074 // the forward links, which are always trustworthy.
4075 // * Add a successor indication. The LockWord is currently encoded as
4076 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4077 // to provide the usual futile-wakeup optimization.
4078 // See RTStt for details.
4079 // * Consider schedctl.sc_nopreempt to cover the critical section.
4080 //
4083 typedef volatile intptr_t MutexT ; // Mux Lock-word
4084 enum MuxBits { LOCKBIT = 1 } ;
4086 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4087 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4088 if (w == 0) return ;
4089 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4090 return ;
4091 }
4093 TEVENT (muxAcquire - Contention) ;
4094 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4095 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4096 for (;;) {
4097 int its = (os::is_MP() ? 100 : 0) + 1 ;
4099 // Optional spin phase: spin-then-park strategy
4100 while (--its >= 0) {
4101 w = *Lock ;
4102 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4103 return ;
4104 }
4105 }
4107 Self->reset() ;
4108 Self->OnList = intptr_t(Lock) ;
4109 // The following fence() isn't _strictly necessary as the subsequent
4110 // CAS() both serializes execution and ratifies the fetched *Lock value.
4111 OrderAccess::fence();
4112 for (;;) {
4113 w = *Lock ;
4114 if ((w & LOCKBIT) == 0) {
4115 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4116 Self->OnList = 0 ; // hygiene - allows stronger asserts
4117 return ;
4118 }
4119 continue ; // Interference -- *Lock changed -- Just retry
4120 }
4121 assert (w & LOCKBIT, "invariant") ;
4122 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4123 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4124 }
4126 while (Self->OnList != 0) {
4127 Self->park() ;
4128 }
4129 }
4130 }
4132 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4133 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4134 if (w == 0) return ;
4135 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4136 return ;
4137 }
4139 TEVENT (muxAcquire - Contention) ;
4140 ParkEvent * ReleaseAfter = NULL ;
4141 if (ev == NULL) {
4142 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4143 }
4144 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4145 for (;;) {
4146 guarantee (ev->OnList == 0, "invariant") ;
4147 int its = (os::is_MP() ? 100 : 0) + 1 ;
4149 // Optional spin phase: spin-then-park strategy
4150 while (--its >= 0) {
4151 w = *Lock ;
4152 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4153 if (ReleaseAfter != NULL) {
4154 ParkEvent::Release (ReleaseAfter) ;
4155 }
4156 return ;
4157 }
4158 }
4160 ev->reset() ;
4161 ev->OnList = intptr_t(Lock) ;
4162 // The following fence() isn't _strictly necessary as the subsequent
4163 // CAS() both serializes execution and ratifies the fetched *Lock value.
4164 OrderAccess::fence();
4165 for (;;) {
4166 w = *Lock ;
4167 if ((w & LOCKBIT) == 0) {
4168 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4169 ev->OnList = 0 ;
4170 // We call ::Release while holding the outer lock, thus
4171 // artificially lengthening the critical section.
4172 // Consider deferring the ::Release() until the subsequent unlock(),
4173 // after we've dropped the outer lock.
4174 if (ReleaseAfter != NULL) {
4175 ParkEvent::Release (ReleaseAfter) ;
4176 }
4177 return ;
4178 }
4179 continue ; // Interference -- *Lock changed -- Just retry
4180 }
4181 assert (w & LOCKBIT, "invariant") ;
4182 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4183 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4184 }
4186 while (ev->OnList != 0) {
4187 ev->park() ;
4188 }
4189 }
4190 }
4192 // Release() must extract a successor from the list and then wake that thread.
4193 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4194 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4195 // Release() would :
4196 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4197 // (B) Extract a successor from the private list "in-hand"
4198 // (C) attempt to CAS() the residual back into *Lock over null.
4199 // If there were any newly arrived threads and the CAS() would fail.
4200 // In that case Release() would detach the RATs, re-merge the list in-hand
4201 // with the RATs and repeat as needed. Alternately, Release() might
4202 // detach and extract a successor, but then pass the residual list to the wakee.
4203 // The wakee would be responsible for reattaching and remerging before it
4204 // competed for the lock.
4205 //
4206 // Both "pop" and DMR are immune from ABA corruption -- there can be
4207 // multiple concurrent pushers, but only one popper or detacher.
4208 // This implementation pops from the head of the list. This is unfair,
4209 // but tends to provide excellent throughput as hot threads remain hot.
4210 // (We wake recently run threads first).
4212 void Thread::muxRelease (volatile intptr_t * Lock) {
4213 for (;;) {
4214 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4215 assert (w & LOCKBIT, "invariant") ;
4216 if (w == LOCKBIT) return ;
4217 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4218 assert (List != NULL, "invariant") ;
4219 assert (List->OnList == intptr_t(Lock), "invariant") ;
4220 ParkEvent * nxt = List->ListNext ;
4222 // The following CAS() releases the lock and pops the head element.
4223 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4224 continue ;
4225 }
4226 List->OnList = 0 ;
4227 OrderAccess::fence() ;
4228 List->unpark () ;
4229 return ;
4230 }
4231 }
4234 void Threads::verify() {
4235 ALL_JAVA_THREADS(p) {
4236 p->verify();
4237 }
4238 VMThread* thread = VMThread::vm_thread();
4239 if (thread != NULL) thread->verify();
4240 }