Mon, 23 Jun 2008 14:11:12 -0700
6708714: Optimize long LShift on 32-bits x86
Summary: For small (1-3 bits) left long shifts in 32-bits VM use sets of add+addc instructions instead of shld+shl on new AMD cpus.
Reviewed-by: never
Contributed-by: shrinivas.joshi@amd.com
1 /*
2 * Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 # include "incls/_precompiled.incl"
26 # include "incls/_thread.cpp.incl"
28 #ifdef DTRACE_ENABLED
30 // Only bother with this argument setup if dtrace is available
32 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
33 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
34 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
35 intptr_t, intptr_t, bool);
36 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
37 intptr_t, intptr_t, bool);
39 #define DTRACE_THREAD_PROBE(probe, javathread) \
40 { \
41 ResourceMark rm(this); \
42 int len = 0; \
43 const char* name = (javathread)->get_thread_name(); \
44 len = strlen(name); \
45 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
46 name, len, \
47 java_lang_Thread::thread_id((javathread)->threadObj()), \
48 (javathread)->osthread()->thread_id(), \
49 java_lang_Thread::is_daemon((javathread)->threadObj())); \
50 }
52 #else // ndef DTRACE_ENABLED
54 #define DTRACE_THREAD_PROBE(probe, javathread)
56 #endif // ndef DTRACE_ENABLED
58 // Class hierarchy
59 // - Thread
60 // - VMThread
61 // - WatcherThread
62 // - ConcurrentMarkSweepThread
63 // - JavaThread
64 // - CompilerThread
66 // ======= Thread ========
68 // Support for forcing alignment of thread objects for biased locking
69 void* Thread::operator new(size_t size) {
70 if (UseBiasedLocking) {
71 const int alignment = markOopDesc::biased_lock_alignment;
72 size_t aligned_size = size + (alignment - sizeof(intptr_t));
73 void* real_malloc_addr = CHeapObj::operator new(aligned_size);
74 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
75 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
76 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
77 "JavaThread alignment code overflowed allocated storage");
78 if (TraceBiasedLocking) {
79 if (aligned_addr != real_malloc_addr)
80 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
81 real_malloc_addr, aligned_addr);
82 }
83 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
84 return aligned_addr;
85 } else {
86 return CHeapObj::operator new(size);
87 }
88 }
90 void Thread::operator delete(void* p) {
91 if (UseBiasedLocking) {
92 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
93 CHeapObj::operator delete(real_malloc_addr);
94 } else {
95 CHeapObj::operator delete(p);
96 }
97 }
100 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
101 // JavaThread
104 Thread::Thread() {
105 // stack
106 _stack_base = NULL;
107 _stack_size = 0;
108 _self_raw_id = 0;
109 _lgrp_id = -1;
110 _osthread = NULL;
112 // allocated data structures
113 set_resource_area(new ResourceArea());
114 set_handle_area(new HandleArea(NULL));
115 set_active_handles(NULL);
116 set_free_handle_block(NULL);
117 set_last_handle_mark(NULL);
118 set_osthread(NULL);
120 // This initial value ==> never claimed.
121 _oops_do_parity = 0;
123 // the handle mark links itself to last_handle_mark
124 new HandleMark(this);
126 // plain initialization
127 debug_only(_owned_locks = NULL;)
128 debug_only(_allow_allocation_count = 0;)
129 NOT_PRODUCT(_allow_safepoint_count = 0;)
130 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
131 _highest_lock = NULL;
132 _jvmti_env_iteration_count = 0;
133 _vm_operation_started_count = 0;
134 _vm_operation_completed_count = 0;
135 _current_pending_monitor = NULL;
136 _current_pending_monitor_is_from_java = true;
137 _current_waiting_monitor = NULL;
138 _num_nested_signal = 0;
139 omFreeList = NULL ;
140 omFreeCount = 0 ;
141 omFreeProvision = 32 ;
143 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
144 _suspend_flags = 0;
146 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
147 _hashStateX = os::random() ;
148 _hashStateY = 842502087 ;
149 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
150 _hashStateW = 273326509 ;
152 _OnTrap = 0 ;
153 _schedctl = NULL ;
154 _Stalled = 0 ;
155 _TypeTag = 0x2BAD ;
157 // Many of the following fields are effectively final - immutable
158 // Note that nascent threads can't use the Native Monitor-Mutex
159 // construct until the _MutexEvent is initialized ...
160 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
161 // we might instead use a stack of ParkEvents that we could provision on-demand.
162 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
163 // and ::Release()
164 _ParkEvent = ParkEvent::Allocate (this) ;
165 _SleepEvent = ParkEvent::Allocate (this) ;
166 _MutexEvent = ParkEvent::Allocate (this) ;
167 _MuxEvent = ParkEvent::Allocate (this) ;
169 #ifdef CHECK_UNHANDLED_OOPS
170 if (CheckUnhandledOops) {
171 _unhandled_oops = new UnhandledOops(this);
172 }
173 #endif // CHECK_UNHANDLED_OOPS
174 #ifdef ASSERT
175 if (UseBiasedLocking) {
176 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
177 assert(this == _real_malloc_address ||
178 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
179 "bug in forced alignment of thread objects");
180 }
181 #endif /* ASSERT */
182 }
184 void Thread::initialize_thread_local_storage() {
185 // Note: Make sure this method only calls
186 // non-blocking operations. Otherwise, it might not work
187 // with the thread-startup/safepoint interaction.
189 // During Java thread startup, safepoint code should allow this
190 // method to complete because it may need to allocate memory to
191 // store information for the new thread.
193 // initialize structure dependent on thread local storage
194 ThreadLocalStorage::set_thread(this);
196 // set up any platform-specific state.
197 os::initialize_thread();
199 }
201 void Thread::record_stack_base_and_size() {
202 set_stack_base(os::current_stack_base());
203 set_stack_size(os::current_stack_size());
204 }
207 Thread::~Thread() {
208 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
209 ObjectSynchronizer::omFlush (this) ;
211 // deallocate data structures
212 delete resource_area();
213 // since the handle marks are using the handle area, we have to deallocated the root
214 // handle mark before deallocating the thread's handle area,
215 assert(last_handle_mark() != NULL, "check we have an element");
216 delete last_handle_mark();
217 assert(last_handle_mark() == NULL, "check we have reached the end");
219 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
220 // We NULL out the fields for good hygiene.
221 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
222 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
223 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
224 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
226 delete handle_area();
228 // osthread() can be NULL, if creation of thread failed.
229 if (osthread() != NULL) os::free_thread(osthread());
231 delete _SR_lock;
233 // clear thread local storage if the Thread is deleting itself
234 if (this == Thread::current()) {
235 ThreadLocalStorage::set_thread(NULL);
236 } else {
237 // In the case where we're not the current thread, invalidate all the
238 // caches in case some code tries to get the current thread or the
239 // thread that was destroyed, and gets stale information.
240 ThreadLocalStorage::invalidate_all();
241 }
242 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
243 }
245 // NOTE: dummy function for assertion purpose.
246 void Thread::run() {
247 ShouldNotReachHere();
248 }
250 #ifdef ASSERT
251 // Private method to check for dangling thread pointer
252 void check_for_dangling_thread_pointer(Thread *thread) {
253 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
254 "possibility of dangling Thread pointer");
255 }
256 #endif
259 #ifndef PRODUCT
260 // Tracing method for basic thread operations
261 void Thread::trace(const char* msg, const Thread* const thread) {
262 if (!TraceThreadEvents) return;
263 ResourceMark rm;
264 ThreadCritical tc;
265 const char *name = "non-Java thread";
266 int prio = -1;
267 if (thread->is_Java_thread()
268 && !thread->is_Compiler_thread()) {
269 // The Threads_lock must be held to get information about
270 // this thread but may not be in some situations when
271 // tracing thread events.
272 bool release_Threads_lock = false;
273 if (!Threads_lock->owned_by_self()) {
274 Threads_lock->lock();
275 release_Threads_lock = true;
276 }
277 JavaThread* jt = (JavaThread *)thread;
278 name = (char *)jt->get_thread_name();
279 oop thread_oop = jt->threadObj();
280 if (thread_oop != NULL) {
281 prio = java_lang_Thread::priority(thread_oop);
282 }
283 if (release_Threads_lock) {
284 Threads_lock->unlock();
285 }
286 }
287 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
288 }
289 #endif
292 ThreadPriority Thread::get_priority(const Thread* const thread) {
293 trace("get priority", thread);
294 ThreadPriority priority;
295 // Can return an error!
296 (void)os::get_priority(thread, priority);
297 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
298 return priority;
299 }
301 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
302 trace("set priority", thread);
303 debug_only(check_for_dangling_thread_pointer(thread);)
304 // Can return an error!
305 (void)os::set_priority(thread, priority);
306 }
309 void Thread::start(Thread* thread) {
310 trace("start", thread);
311 // Start is different from resume in that its safety is guaranteed by context or
312 // being called from a Java method synchronized on the Thread object.
313 if (!DisableStartThread) {
314 if (thread->is_Java_thread()) {
315 // Initialize the thread state to RUNNABLE before starting this thread.
316 // Can not set it after the thread started because we do not know the
317 // exact thread state at that time. It could be in MONITOR_WAIT or
318 // in SLEEPING or some other state.
319 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
320 java_lang_Thread::RUNNABLE);
321 }
322 os::start_thread(thread);
323 }
324 }
326 // Enqueue a VM_Operation to do the job for us - sometime later
327 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
328 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
329 VMThread::execute(vm_stop);
330 }
333 //
334 // Check if an external suspend request has completed (or has been
335 // cancelled). Returns true if the thread is externally suspended and
336 // false otherwise.
337 //
338 // The bits parameter returns information about the code path through
339 // the routine. Useful for debugging:
340 //
341 // set in is_ext_suspend_completed():
342 // 0x00000001 - routine was entered
343 // 0x00000010 - routine return false at end
344 // 0x00000100 - thread exited (return false)
345 // 0x00000200 - suspend request cancelled (return false)
346 // 0x00000400 - thread suspended (return true)
347 // 0x00001000 - thread is in a suspend equivalent state (return true)
348 // 0x00002000 - thread is native and walkable (return true)
349 // 0x00004000 - thread is native_trans and walkable (needed retry)
350 //
351 // set in wait_for_ext_suspend_completion():
352 // 0x00010000 - routine was entered
353 // 0x00020000 - suspend request cancelled before loop (return false)
354 // 0x00040000 - thread suspended before loop (return true)
355 // 0x00080000 - suspend request cancelled in loop (return false)
356 // 0x00100000 - thread suspended in loop (return true)
357 // 0x00200000 - suspend not completed during retry loop (return false)
358 //
360 // Helper class for tracing suspend wait debug bits.
361 //
362 // 0x00000100 indicates that the target thread exited before it could
363 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
364 // 0x00080000 each indicate a cancelled suspend request so they don't
365 // count as wait failures either.
366 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
368 class TraceSuspendDebugBits : public StackObj {
369 private:
370 JavaThread * jt;
371 bool is_wait;
372 bool called_by_wait; // meaningful when !is_wait
373 uint32_t * bits;
375 public:
376 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
377 uint32_t *_bits) {
378 jt = _jt;
379 is_wait = _is_wait;
380 called_by_wait = _called_by_wait;
381 bits = _bits;
382 }
384 ~TraceSuspendDebugBits() {
385 if (!is_wait) {
386 #if 1
387 // By default, don't trace bits for is_ext_suspend_completed() calls.
388 // That trace is very chatty.
389 return;
390 #else
391 if (!called_by_wait) {
392 // If tracing for is_ext_suspend_completed() is enabled, then only
393 // trace calls to it from wait_for_ext_suspend_completion()
394 return;
395 }
396 #endif
397 }
399 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
400 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
401 MutexLocker ml(Threads_lock); // needed for get_thread_name()
402 ResourceMark rm;
404 tty->print_cr(
405 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
406 jt->get_thread_name(), *bits);
408 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
409 }
410 }
411 }
412 };
413 #undef DEBUG_FALSE_BITS
416 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
417 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
419 bool did_trans_retry = false; // only do thread_in_native_trans retry once
420 bool do_trans_retry; // flag to force the retry
422 *bits |= 0x00000001;
424 do {
425 do_trans_retry = false;
427 if (is_exiting()) {
428 // Thread is in the process of exiting. This is always checked
429 // first to reduce the risk of dereferencing a freed JavaThread.
430 *bits |= 0x00000100;
431 return false;
432 }
434 if (!is_external_suspend()) {
435 // Suspend request is cancelled. This is always checked before
436 // is_ext_suspended() to reduce the risk of a rogue resume
437 // confusing the thread that made the suspend request.
438 *bits |= 0x00000200;
439 return false;
440 }
442 if (is_ext_suspended()) {
443 // thread is suspended
444 *bits |= 0x00000400;
445 return true;
446 }
448 // Now that we no longer do hard suspends of threads running
449 // native code, the target thread can be changing thread state
450 // while we are in this routine:
451 //
452 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
453 //
454 // We save a copy of the thread state as observed at this moment
455 // and make our decision about suspend completeness based on the
456 // copy. This closes the race where the thread state is seen as
457 // _thread_in_native_trans in the if-thread_blocked check, but is
458 // seen as _thread_blocked in if-thread_in_native_trans check.
459 JavaThreadState save_state = thread_state();
461 if (save_state == _thread_blocked && is_suspend_equivalent()) {
462 // If the thread's state is _thread_blocked and this blocking
463 // condition is known to be equivalent to a suspend, then we can
464 // consider the thread to be externally suspended. This means that
465 // the code that sets _thread_blocked has been modified to do
466 // self-suspension if the blocking condition releases. We also
467 // used to check for CONDVAR_WAIT here, but that is now covered by
468 // the _thread_blocked with self-suspension check.
469 //
470 // Return true since we wouldn't be here unless there was still an
471 // external suspend request.
472 *bits |= 0x00001000;
473 return true;
474 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
475 // Threads running native code will self-suspend on native==>VM/Java
476 // transitions. If its stack is walkable (should always be the case
477 // unless this function is called before the actual java_suspend()
478 // call), then the wait is done.
479 *bits |= 0x00002000;
480 return true;
481 } else if (!called_by_wait && !did_trans_retry &&
482 save_state == _thread_in_native_trans &&
483 frame_anchor()->walkable()) {
484 // The thread is transitioning from thread_in_native to another
485 // thread state. check_safepoint_and_suspend_for_native_trans()
486 // will force the thread to self-suspend. If it hasn't gotten
487 // there yet we may have caught the thread in-between the native
488 // code check above and the self-suspend. Lucky us. If we were
489 // called by wait_for_ext_suspend_completion(), then it
490 // will be doing the retries so we don't have to.
491 //
492 // Since we use the saved thread state in the if-statement above,
493 // there is a chance that the thread has already transitioned to
494 // _thread_blocked by the time we get here. In that case, we will
495 // make a single unnecessary pass through the logic below. This
496 // doesn't hurt anything since we still do the trans retry.
498 *bits |= 0x00004000;
500 // Once the thread leaves thread_in_native_trans for another
501 // thread state, we break out of this retry loop. We shouldn't
502 // need this flag to prevent us from getting back here, but
503 // sometimes paranoia is good.
504 did_trans_retry = true;
506 // We wait for the thread to transition to a more usable state.
507 for (int i = 1; i <= SuspendRetryCount; i++) {
508 // We used to do an "os::yield_all(i)" call here with the intention
509 // that yielding would increase on each retry. However, the parameter
510 // is ignored on Linux which means the yield didn't scale up. Waiting
511 // on the SR_lock below provides a much more predictable scale up for
512 // the delay. It also provides a simple/direct point to check for any
513 // safepoint requests from the VMThread
515 // temporarily drops SR_lock while doing wait with safepoint check
516 // (if we're a JavaThread - the WatcherThread can also call this)
517 // and increase delay with each retry
518 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
520 // check the actual thread state instead of what we saved above
521 if (thread_state() != _thread_in_native_trans) {
522 // the thread has transitioned to another thread state so
523 // try all the checks (except this one) one more time.
524 do_trans_retry = true;
525 break;
526 }
527 } // end retry loop
530 }
531 } while (do_trans_retry);
533 *bits |= 0x00000010;
534 return false;
535 }
537 //
538 // Wait for an external suspend request to complete (or be cancelled).
539 // Returns true if the thread is externally suspended and false otherwise.
540 //
541 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
542 uint32_t *bits) {
543 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
544 false /* !called_by_wait */, bits);
546 // local flag copies to minimize SR_lock hold time
547 bool is_suspended;
548 bool pending;
549 uint32_t reset_bits;
551 // set a marker so is_ext_suspend_completed() knows we are the caller
552 *bits |= 0x00010000;
554 // We use reset_bits to reinitialize the bits value at the top of
555 // each retry loop. This allows the caller to make use of any
556 // unused bits for their own marking purposes.
557 reset_bits = *bits;
559 {
560 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
561 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
562 delay, bits);
563 pending = is_external_suspend();
564 }
565 // must release SR_lock to allow suspension to complete
567 if (!pending) {
568 // A cancelled suspend request is the only false return from
569 // is_ext_suspend_completed() that keeps us from entering the
570 // retry loop.
571 *bits |= 0x00020000;
572 return false;
573 }
575 if (is_suspended) {
576 *bits |= 0x00040000;
577 return true;
578 }
580 for (int i = 1; i <= retries; i++) {
581 *bits = reset_bits; // reinit to only track last retry
583 // We used to do an "os::yield_all(i)" call here with the intention
584 // that yielding would increase on each retry. However, the parameter
585 // is ignored on Linux which means the yield didn't scale up. Waiting
586 // on the SR_lock below provides a much more predictable scale up for
587 // the delay. It also provides a simple/direct point to check for any
588 // safepoint requests from the VMThread
590 {
591 MutexLocker ml(SR_lock());
592 // wait with safepoint check (if we're a JavaThread - the WatcherThread
593 // can also call this) and increase delay with each retry
594 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
596 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
597 delay, bits);
599 // It is possible for the external suspend request to be cancelled
600 // (by a resume) before the actual suspend operation is completed.
601 // Refresh our local copy to see if we still need to wait.
602 pending = is_external_suspend();
603 }
605 if (!pending) {
606 // A cancelled suspend request is the only false return from
607 // is_ext_suspend_completed() that keeps us from staying in the
608 // retry loop.
609 *bits |= 0x00080000;
610 return false;
611 }
613 if (is_suspended) {
614 *bits |= 0x00100000;
615 return true;
616 }
617 } // end retry loop
619 // thread did not suspend after all our retries
620 *bits |= 0x00200000;
621 return false;
622 }
624 #ifndef PRODUCT
625 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
627 // This should not need to be atomic as the only way for simultaneous
628 // updates is via interrupts. Even then this should be rare or non-existant
629 // and we don't care that much anyway.
631 int index = _jmp_ring_index;
632 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
633 _jmp_ring[index]._target = (intptr_t) target;
634 _jmp_ring[index]._instruction = (intptr_t) instr;
635 _jmp_ring[index]._file = file;
636 _jmp_ring[index]._line = line;
637 }
638 #endif /* PRODUCT */
640 // Called by flat profiler
641 // Callers have already called wait_for_ext_suspend_completion
642 // The assertion for that is currently too complex to put here:
643 bool JavaThread::profile_last_Java_frame(frame* _fr) {
644 bool gotframe = false;
645 // self suspension saves needed state.
646 if (has_last_Java_frame() && _anchor.walkable()) {
647 *_fr = pd_last_frame();
648 gotframe = true;
649 }
650 return gotframe;
651 }
653 void Thread::interrupt(Thread* thread) {
654 trace("interrupt", thread);
655 debug_only(check_for_dangling_thread_pointer(thread);)
656 os::interrupt(thread);
657 }
659 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
660 trace("is_interrupted", thread);
661 debug_only(check_for_dangling_thread_pointer(thread);)
662 // Note: If clear_interrupted==false, this simply fetches and
663 // returns the value of the field osthread()->interrupted().
664 return os::is_interrupted(thread, clear_interrupted);
665 }
668 // GC Support
669 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
670 jint thread_parity = _oops_do_parity;
671 if (thread_parity != strong_roots_parity) {
672 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
673 if (res == thread_parity) return true;
674 else {
675 guarantee(res == strong_roots_parity, "Or else what?");
676 assert(SharedHeap::heap()->n_par_threads() > 0,
677 "Should only fail when parallel.");
678 return false;
679 }
680 }
681 assert(SharedHeap::heap()->n_par_threads() > 0,
682 "Should only fail when parallel.");
683 return false;
684 }
686 void Thread::oops_do(OopClosure* f) {
687 active_handles()->oops_do(f);
688 // Do oop for ThreadShadow
689 f->do_oop((oop*)&_pending_exception);
690 handle_area()->oops_do(f);
691 }
693 void Thread::nmethods_do() {
694 }
696 void Thread::print_on(outputStream* st) const {
697 // get_priority assumes osthread initialized
698 if (osthread() != NULL) {
699 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
700 osthread()->print_on(st);
701 }
702 debug_only(if (WizardMode) print_owned_locks_on(st);)
703 }
705 // Thread::print_on_error() is called by fatal error handler. Don't use
706 // any lock or allocate memory.
707 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
708 if (is_VM_thread()) st->print("VMThread");
709 else if (is_Compiler_thread()) st->print("CompilerThread");
710 else if (is_Java_thread()) st->print("JavaThread");
711 else if (is_GC_task_thread()) st->print("GCTaskThread");
712 else if (is_Watcher_thread()) st->print("WatcherThread");
713 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
714 else st->print("Thread");
716 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
717 _stack_base - _stack_size, _stack_base);
719 if (osthread()) {
720 st->print(" [id=%d]", osthread()->thread_id());
721 }
722 }
724 #ifdef ASSERT
725 void Thread::print_owned_locks_on(outputStream* st) const {
726 Monitor *cur = _owned_locks;
727 if (cur == NULL) {
728 st->print(" (no locks) ");
729 } else {
730 st->print_cr(" Locks owned:");
731 while(cur) {
732 cur->print_on(st);
733 cur = cur->next();
734 }
735 }
736 }
738 static int ref_use_count = 0;
740 bool Thread::owns_locks_but_compiled_lock() const {
741 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
742 if (cur != Compile_lock) return true;
743 }
744 return false;
745 }
748 #endif
750 #ifndef PRODUCT
752 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
753 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
754 // no threads which allow_vm_block's are held
755 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
756 // Check if current thread is allowed to block at a safepoint
757 if (!(_allow_safepoint_count == 0))
758 fatal("Possible safepoint reached by thread that does not allow it");
759 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
760 fatal("LEAF method calling lock?");
761 }
763 #ifdef ASSERT
764 if (potential_vm_operation && is_Java_thread()
765 && !Universe::is_bootstrapping()) {
766 // Make sure we do not hold any locks that the VM thread also uses.
767 // This could potentially lead to deadlocks
768 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
769 // Threads_lock is special, since the safepoint synchronization will not start before this is
770 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
771 // since it is used to transfer control between JavaThreads and the VMThread
772 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
773 if ( (cur->allow_vm_block() &&
774 cur != Threads_lock &&
775 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
776 cur != VMOperationRequest_lock &&
777 cur != VMOperationQueue_lock) ||
778 cur->rank() == Mutex::special) {
779 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
780 }
781 }
782 }
784 if (GCALotAtAllSafepoints) {
785 // We could enter a safepoint here and thus have a gc
786 InterfaceSupport::check_gc_alot();
787 }
789 #endif
790 }
791 #endif
793 bool Thread::lock_is_in_stack(address adr) const {
794 assert(Thread::current() == this, "lock_is_in_stack can only be called from current thread");
795 // High limit: highest_lock is set during thread execution
796 // Low limit: address of the local variable dummy, rounded to 4K boundary.
797 // (The rounding helps finding threads in unsafe mode, even if the particular stack
798 // frame has been popped already. Correct as long as stacks are at least 4K long and aligned.)
799 address end = os::current_stack_pointer();
800 if (_highest_lock >= adr && adr >= end) return true;
802 return false;
803 }
806 bool Thread::is_in_stack(address adr) const {
807 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
808 address end = os::current_stack_pointer();
809 if (stack_base() >= adr && adr >= end) return true;
811 return false;
812 }
815 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
816 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
817 // used for compilation in the future. If that change is made, the need for these methods
818 // should be revisited, and they should be removed if possible.
820 bool Thread::is_lock_owned(address adr) const {
821 if (lock_is_in_stack(adr) ) return true;
822 return false;
823 }
825 bool Thread::set_as_starting_thread() {
826 // NOTE: this must be called inside the main thread.
827 return os::create_main_thread((JavaThread*)this);
828 }
830 static void initialize_class(symbolHandle class_name, TRAPS) {
831 klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
832 instanceKlass::cast(klass)->initialize(CHECK);
833 }
836 // Creates the initial ThreadGroup
837 static Handle create_initial_thread_group(TRAPS) {
838 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_ThreadGroup(), true, CHECK_NH);
839 instanceKlassHandle klass (THREAD, k);
841 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
842 {
843 JavaValue result(T_VOID);
844 JavaCalls::call_special(&result,
845 system_instance,
846 klass,
847 vmSymbolHandles::object_initializer_name(),
848 vmSymbolHandles::void_method_signature(),
849 CHECK_NH);
850 }
851 Universe::set_system_thread_group(system_instance());
853 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
854 {
855 JavaValue result(T_VOID);
856 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
857 JavaCalls::call_special(&result,
858 main_instance,
859 klass,
860 vmSymbolHandles::object_initializer_name(),
861 vmSymbolHandles::threadgroup_string_void_signature(),
862 system_instance,
863 string,
864 CHECK_NH);
865 }
866 return main_instance;
867 }
869 // Creates the initial Thread
870 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
871 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK_NULL);
872 instanceKlassHandle klass (THREAD, k);
873 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
875 java_lang_Thread::set_thread(thread_oop(), thread);
876 java_lang_Thread::set_priority(thread_oop(), NormPriority);
877 thread->set_threadObj(thread_oop());
879 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
881 JavaValue result(T_VOID);
882 JavaCalls::call_special(&result, thread_oop,
883 klass,
884 vmSymbolHandles::object_initializer_name(),
885 vmSymbolHandles::threadgroup_string_void_signature(),
886 thread_group,
887 string,
888 CHECK_NULL);
889 return thread_oop();
890 }
892 static void call_initializeSystemClass(TRAPS) {
893 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
894 instanceKlassHandle klass (THREAD, k);
896 JavaValue result(T_VOID);
897 JavaCalls::call_static(&result, klass, vmSymbolHandles::initializeSystemClass_name(),
898 vmSymbolHandles::void_method_signature(), CHECK);
899 }
901 static void reset_vm_info_property(TRAPS) {
902 // the vm info string
903 ResourceMark rm(THREAD);
904 const char *vm_info = VM_Version::vm_info_string();
906 // java.lang.System class
907 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
908 instanceKlassHandle klass (THREAD, k);
910 // setProperty arguments
911 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
912 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
914 // return value
915 JavaValue r(T_OBJECT);
917 // public static String setProperty(String key, String value);
918 JavaCalls::call_static(&r,
919 klass,
920 vmSymbolHandles::setProperty_name(),
921 vmSymbolHandles::string_string_string_signature(),
922 key_str,
923 value_str,
924 CHECK);
925 }
928 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
929 assert(thread_group.not_null(), "thread group should be specified");
930 assert(threadObj() == NULL, "should only create Java thread object once");
932 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
933 instanceKlassHandle klass (THREAD, k);
934 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
936 java_lang_Thread::set_thread(thread_oop(), this);
937 java_lang_Thread::set_priority(thread_oop(), NormPriority);
938 set_threadObj(thread_oop());
940 JavaValue result(T_VOID);
941 if (thread_name != NULL) {
942 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
943 // Thread gets assigned specified name and null target
944 JavaCalls::call_special(&result,
945 thread_oop,
946 klass,
947 vmSymbolHandles::object_initializer_name(),
948 vmSymbolHandles::threadgroup_string_void_signature(),
949 thread_group, // Argument 1
950 name, // Argument 2
951 THREAD);
952 } else {
953 // Thread gets assigned name "Thread-nnn" and null target
954 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
955 JavaCalls::call_special(&result,
956 thread_oop,
957 klass,
958 vmSymbolHandles::object_initializer_name(),
959 vmSymbolHandles::threadgroup_runnable_void_signature(),
960 thread_group, // Argument 1
961 Handle(), // Argument 2
962 THREAD);
963 }
966 if (daemon) {
967 java_lang_Thread::set_daemon(thread_oop());
968 }
970 if (HAS_PENDING_EXCEPTION) {
971 return;
972 }
974 KlassHandle group(this, SystemDictionary::threadGroup_klass());
975 Handle threadObj(this, this->threadObj());
977 JavaCalls::call_special(&result,
978 thread_group,
979 group,
980 vmSymbolHandles::add_method_name(),
981 vmSymbolHandles::thread_void_signature(),
982 threadObj, // Arg 1
983 THREAD);
986 }
988 // NamedThread -- non-JavaThread subclasses with multiple
989 // uniquely named instances should derive from this.
990 NamedThread::NamedThread() : Thread() {
991 _name = NULL;
992 }
994 NamedThread::~NamedThread() {
995 if (_name != NULL) {
996 FREE_C_HEAP_ARRAY(char, _name);
997 _name = NULL;
998 }
999 }
1001 void NamedThread::set_name(const char* format, ...) {
1002 guarantee(_name == NULL, "Only get to set name once.");
1003 _name = NEW_C_HEAP_ARRAY(char, max_name_len);
1004 guarantee(_name != NULL, "alloc failure");
1005 va_list ap;
1006 va_start(ap, format);
1007 jio_vsnprintf(_name, max_name_len, format, ap);
1008 va_end(ap);
1009 }
1011 // ======= WatcherThread ========
1013 // The watcher thread exists to simulate timer interrupts. It should
1014 // be replaced by an abstraction over whatever native support for
1015 // timer interrupts exists on the platform.
1017 WatcherThread* WatcherThread::_watcher_thread = NULL;
1018 bool WatcherThread::_should_terminate = false;
1020 WatcherThread::WatcherThread() : Thread() {
1021 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1022 if (os::create_thread(this, os::watcher_thread)) {
1023 _watcher_thread = this;
1025 // Set the watcher thread to the highest OS priority which should not be
1026 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1027 // is created. The only normal thread using this priority is the reference
1028 // handler thread, which runs for very short intervals only.
1029 // If the VMThread's priority is not lower than the WatcherThread profiling
1030 // will be inaccurate.
1031 os::set_priority(this, MaxPriority);
1032 if (!DisableStartThread) {
1033 os::start_thread(this);
1034 }
1035 }
1036 }
1038 void WatcherThread::run() {
1039 assert(this == watcher_thread(), "just checking");
1041 this->record_stack_base_and_size();
1042 this->initialize_thread_local_storage();
1043 this->set_active_handles(JNIHandleBlock::allocate_block());
1044 while(!_should_terminate) {
1045 assert(watcher_thread() == Thread::current(), "thread consistency check");
1046 assert(watcher_thread() == this, "thread consistency check");
1048 // Calculate how long it'll be until the next PeriodicTask work
1049 // should be done, and sleep that amount of time.
1050 const size_t time_to_wait = PeriodicTask::time_to_wait();
1051 os::sleep(this, time_to_wait, false);
1053 if (is_error_reported()) {
1054 // A fatal error has happened, the error handler(VMError::report_and_die)
1055 // should abort JVM after creating an error log file. However in some
1056 // rare cases, the error handler itself might deadlock. Here we try to
1057 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1058 //
1059 // This code is in WatcherThread because WatcherThread wakes up
1060 // periodically so the fatal error handler doesn't need to do anything;
1061 // also because the WatcherThread is less likely to crash than other
1062 // threads.
1064 for (;;) {
1065 if (!ShowMessageBoxOnError
1066 && (OnError == NULL || OnError[0] == '\0')
1067 && Arguments::abort_hook() == NULL) {
1068 os::sleep(this, 2 * 60 * 1000, false);
1069 fdStream err(defaultStream::output_fd());
1070 err.print_raw_cr("# [ timer expired, abort... ]");
1071 // skip atexit/vm_exit/vm_abort hooks
1072 os::die();
1073 }
1075 // Wake up 5 seconds later, the fatal handler may reset OnError or
1076 // ShowMessageBoxOnError when it is ready to abort.
1077 os::sleep(this, 5 * 1000, false);
1078 }
1079 }
1081 PeriodicTask::real_time_tick(time_to_wait);
1083 // If we have no more tasks left due to dynamic disenrollment,
1084 // shut down the thread since we don't currently support dynamic enrollment
1085 if (PeriodicTask::num_tasks() == 0) {
1086 _should_terminate = true;
1087 }
1088 }
1090 // Signal that it is terminated
1091 {
1092 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1093 _watcher_thread = NULL;
1094 Terminator_lock->notify();
1095 }
1097 // Thread destructor usually does this..
1098 ThreadLocalStorage::set_thread(NULL);
1099 }
1101 void WatcherThread::start() {
1102 if (watcher_thread() == NULL) {
1103 _should_terminate = false;
1104 // Create the single instance of WatcherThread
1105 new WatcherThread();
1106 }
1107 }
1109 void WatcherThread::stop() {
1110 // it is ok to take late safepoints here, if needed
1111 MutexLocker mu(Terminator_lock);
1112 _should_terminate = true;
1113 while(watcher_thread() != NULL) {
1114 // This wait should make safepoint checks, wait without a timeout,
1115 // and wait as a suspend-equivalent condition.
1116 //
1117 // Note: If the FlatProfiler is running, then this thread is waiting
1118 // for the WatcherThread to terminate and the WatcherThread, via the
1119 // FlatProfiler task, is waiting for the external suspend request on
1120 // this thread to complete. wait_for_ext_suspend_completion() will
1121 // eventually timeout, but that takes time. Making this wait a
1122 // suspend-equivalent condition solves that timeout problem.
1123 //
1124 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1125 Mutex::_as_suspend_equivalent_flag);
1126 }
1127 }
1129 void WatcherThread::print_on(outputStream* st) const {
1130 st->print("\"%s\" ", name());
1131 Thread::print_on(st);
1132 st->cr();
1133 }
1135 // ======= JavaThread ========
1137 // A JavaThread is a normal Java thread
1139 void JavaThread::initialize() {
1140 // Initialize fields
1141 set_saved_exception_pc(NULL);
1142 set_threadObj(NULL);
1143 _anchor.clear();
1144 set_entry_point(NULL);
1145 set_jni_functions(jni_functions());
1146 set_callee_target(NULL);
1147 set_vm_result(NULL);
1148 set_vm_result_2(NULL);
1149 set_vframe_array_head(NULL);
1150 set_vframe_array_last(NULL);
1151 set_deferred_locals(NULL);
1152 set_deopt_mark(NULL);
1153 clear_must_deopt_id();
1154 set_monitor_chunks(NULL);
1155 set_next(NULL);
1156 set_thread_state(_thread_new);
1157 _terminated = _not_terminated;
1158 _privileged_stack_top = NULL;
1159 _array_for_gc = NULL;
1160 _suspend_equivalent = false;
1161 _in_deopt_handler = 0;
1162 _doing_unsafe_access = false;
1163 _stack_guard_state = stack_guard_unused;
1164 _exception_oop = NULL;
1165 _exception_pc = 0;
1166 _exception_handler_pc = 0;
1167 _exception_stack_size = 0;
1168 _jvmti_thread_state= NULL;
1169 _jvmti_get_loaded_classes_closure = NULL;
1170 _interp_only_mode = 0;
1171 _special_runtime_exit_condition = _no_async_condition;
1172 _pending_async_exception = NULL;
1173 _is_compiling = false;
1174 _thread_stat = NULL;
1175 _thread_stat = new ThreadStatistics();
1176 _blocked_on_compilation = false;
1177 _jni_active_critical = 0;
1178 _do_not_unlock_if_synchronized = false;
1179 _cached_monitor_info = NULL;
1180 _parker = Parker::Allocate(this) ;
1182 #ifndef PRODUCT
1183 _jmp_ring_index = 0;
1184 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1185 record_jump(NULL, NULL, NULL, 0);
1186 }
1187 #endif /* PRODUCT */
1189 set_thread_profiler(NULL);
1190 if (FlatProfiler::is_active()) {
1191 // This is where we would decide to either give each thread it's own profiler
1192 // or use one global one from FlatProfiler,
1193 // or up to some count of the number of profiled threads, etc.
1194 ThreadProfiler* pp = new ThreadProfiler();
1195 pp->engage();
1196 set_thread_profiler(pp);
1197 }
1199 // Setup safepoint state info for this thread
1200 ThreadSafepointState::create(this);
1202 debug_only(_java_call_counter = 0);
1204 // JVMTI PopFrame support
1205 _popframe_condition = popframe_inactive;
1206 _popframe_preserved_args = NULL;
1207 _popframe_preserved_args_size = 0;
1209 pd_initialize();
1210 }
1212 JavaThread::JavaThread(bool is_attaching) : Thread() {
1213 initialize();
1214 _is_attaching = is_attaching;
1215 }
1217 bool JavaThread::reguard_stack(address cur_sp) {
1218 if (_stack_guard_state != stack_guard_yellow_disabled) {
1219 return true; // Stack already guarded or guard pages not needed.
1220 }
1222 if (register_stack_overflow()) {
1223 // For those architectures which have separate register and
1224 // memory stacks, we must check the register stack to see if
1225 // it has overflowed.
1226 return false;
1227 }
1229 // Java code never executes within the yellow zone: the latter is only
1230 // there to provoke an exception during stack banging. If java code
1231 // is executing there, either StackShadowPages should be larger, or
1232 // some exception code in c1, c2 or the interpreter isn't unwinding
1233 // when it should.
1234 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1236 enable_stack_yellow_zone();
1237 return true;
1238 }
1240 bool JavaThread::reguard_stack(void) {
1241 return reguard_stack(os::current_stack_pointer());
1242 }
1245 void JavaThread::block_if_vm_exited() {
1246 if (_terminated == _vm_exited) {
1247 // _vm_exited is set at safepoint, and Threads_lock is never released
1248 // we will block here forever
1249 Threads_lock->lock_without_safepoint_check();
1250 ShouldNotReachHere();
1251 }
1252 }
1255 // Remove this ifdef when C1 is ported to the compiler interface.
1256 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1258 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : Thread() {
1259 if (TraceThreadEvents) {
1260 tty->print_cr("creating thread %p", this);
1261 }
1262 initialize();
1263 _is_attaching = false;
1264 set_entry_point(entry_point);
1265 // Create the native thread itself.
1266 // %note runtime_23
1267 os::ThreadType thr_type = os::java_thread;
1268 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1269 os::java_thread;
1270 os::create_thread(this, thr_type, stack_sz);
1272 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1273 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1274 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1275 // the exception consists of creating the exception object & initializing it, initialization
1276 // will leave the VM via a JavaCall and then all locks must be unlocked).
1277 //
1278 // The thread is still suspended when we reach here. Thread must be explicit started
1279 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1280 // by calling Threads:add. The reason why this is not done here, is because the thread
1281 // object must be fully initialized (take a look at JVM_Start)
1282 }
1284 JavaThread::~JavaThread() {
1285 if (TraceThreadEvents) {
1286 tty->print_cr("terminate thread %p", this);
1287 }
1289 // JSR166 -- return the parker to the free list
1290 Parker::Release(_parker);
1291 _parker = NULL ;
1293 // Free any remaining previous UnrollBlock
1294 vframeArray* old_array = vframe_array_last();
1296 if (old_array != NULL) {
1297 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1298 old_array->set_unroll_block(NULL);
1299 delete old_info;
1300 delete old_array;
1301 }
1303 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1304 if (deferred != NULL) {
1305 // This can only happen if thread is destroyed before deoptimization occurs.
1306 assert(deferred->length() != 0, "empty array!");
1307 do {
1308 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1309 deferred->remove_at(0);
1310 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1311 delete dlv;
1312 } while (deferred->length() != 0);
1313 delete deferred;
1314 }
1316 // All Java related clean up happens in exit
1317 ThreadSafepointState::destroy(this);
1318 if (_thread_profiler != NULL) delete _thread_profiler;
1319 if (_thread_stat != NULL) delete _thread_stat;
1320 }
1323 // The first routine called by a new Java thread
1324 void JavaThread::run() {
1325 // initialize thread-local alloc buffer related fields
1326 this->initialize_tlab();
1328 // used to test validitity of stack trace backs
1329 this->record_base_of_stack_pointer();
1331 // Record real stack base and size.
1332 this->record_stack_base_and_size();
1334 // Initialize thread local storage; set before calling MutexLocker
1335 this->initialize_thread_local_storage();
1337 this->create_stack_guard_pages();
1339 // Thread is now sufficient initialized to be handled by the safepoint code as being
1340 // in the VM. Change thread state from _thread_new to _thread_in_vm
1341 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1343 assert(JavaThread::current() == this, "sanity check");
1344 assert(!Thread::current()->owns_locks(), "sanity check");
1346 DTRACE_THREAD_PROBE(start, this);
1348 // This operation might block. We call that after all safepoint checks for a new thread has
1349 // been completed.
1350 this->set_active_handles(JNIHandleBlock::allocate_block());
1352 if (JvmtiExport::should_post_thread_life()) {
1353 JvmtiExport::post_thread_start(this);
1354 }
1356 // We call another function to do the rest so we are sure that the stack addresses used
1357 // from there will be lower than the stack base just computed
1358 thread_main_inner();
1360 // Note, thread is no longer valid at this point!
1361 }
1364 void JavaThread::thread_main_inner() {
1365 assert(JavaThread::current() == this, "sanity check");
1366 assert(this->threadObj() != NULL, "just checking");
1368 // Execute thread entry point. If this thread is being asked to restart,
1369 // or has been stopped before starting, do not reexecute entry point.
1370 // Note: Due to JVM_StopThread we can have pending exceptions already!
1371 if (!this->has_pending_exception() && !java_lang_Thread::is_stillborn(this->threadObj())) {
1372 // enter the thread's entry point only if we have no pending exceptions
1373 HandleMark hm(this);
1374 this->entry_point()(this, this);
1375 }
1377 DTRACE_THREAD_PROBE(stop, this);
1379 this->exit(false);
1380 delete this;
1381 }
1384 static void ensure_join(JavaThread* thread) {
1385 // We do not need to grap the Threads_lock, since we are operating on ourself.
1386 Handle threadObj(thread, thread->threadObj());
1387 assert(threadObj.not_null(), "java thread object must exist");
1388 ObjectLocker lock(threadObj, thread);
1389 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1390 thread->clear_pending_exception();
1391 // It is of profound importance that we set the stillborn bit and reset the thread object,
1392 // before we do the notify. Since, changing these two variable will make JVM_IsAlive return
1393 // false. So in case another thread is doing a join on this thread , it will detect that the thread
1394 // is dead when it gets notified.
1395 java_lang_Thread::set_stillborn(threadObj());
1396 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1397 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1398 java_lang_Thread::set_thread(threadObj(), NULL);
1399 lock.notify_all(thread);
1400 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1401 thread->clear_pending_exception();
1402 }
1404 // For any new cleanup additions, please check to see if they need to be applied to
1405 // cleanup_failed_attach_current_thread as well.
1406 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1407 assert(this == JavaThread::current(), "thread consistency check");
1408 if (!InitializeJavaLangSystem) return;
1410 HandleMark hm(this);
1411 Handle uncaught_exception(this, this->pending_exception());
1412 this->clear_pending_exception();
1413 Handle threadObj(this, this->threadObj());
1414 assert(threadObj.not_null(), "Java thread object should be created");
1416 if (get_thread_profiler() != NULL) {
1417 get_thread_profiler()->disengage();
1418 ResourceMark rm;
1419 get_thread_profiler()->print(get_thread_name());
1420 }
1423 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1424 {
1425 EXCEPTION_MARK;
1427 CLEAR_PENDING_EXCEPTION;
1428 }
1429 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1430 // has to be fixed by a runtime query method
1431 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1432 // JSR-166: change call from from ThreadGroup.uncaughtException to
1433 // java.lang.Thread.dispatchUncaughtException
1434 if (uncaught_exception.not_null()) {
1435 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1436 Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT",
1437 (address)uncaught_exception(), (address)threadObj(), (address)group());
1438 {
1439 EXCEPTION_MARK;
1440 // Check if the method Thread.dispatchUncaughtException() exists. If so
1441 // call it. Otherwise we have an older library without the JSR-166 changes,
1442 // so call ThreadGroup.uncaughtException()
1443 KlassHandle recvrKlass(THREAD, threadObj->klass());
1444 CallInfo callinfo;
1445 KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass());
1446 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1447 vmSymbolHandles::dispatchUncaughtException_name(),
1448 vmSymbolHandles::throwable_void_signature(),
1449 KlassHandle(), false, false, THREAD);
1450 CLEAR_PENDING_EXCEPTION;
1451 methodHandle method = callinfo.selected_method();
1452 if (method.not_null()) {
1453 JavaValue result(T_VOID);
1454 JavaCalls::call_virtual(&result,
1455 threadObj, thread_klass,
1456 vmSymbolHandles::dispatchUncaughtException_name(),
1457 vmSymbolHandles::throwable_void_signature(),
1458 uncaught_exception,
1459 THREAD);
1460 } else {
1461 KlassHandle thread_group(THREAD, SystemDictionary::threadGroup_klass());
1462 JavaValue result(T_VOID);
1463 JavaCalls::call_virtual(&result,
1464 group, thread_group,
1465 vmSymbolHandles::uncaughtException_name(),
1466 vmSymbolHandles::thread_throwable_void_signature(),
1467 threadObj, // Arg 1
1468 uncaught_exception, // Arg 2
1469 THREAD);
1470 }
1471 CLEAR_PENDING_EXCEPTION;
1472 }
1473 }
1475 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1476 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1477 // is deprecated anyhow.
1478 { int count = 3;
1479 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1480 EXCEPTION_MARK;
1481 JavaValue result(T_VOID);
1482 KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass());
1483 JavaCalls::call_virtual(&result,
1484 threadObj, thread_klass,
1485 vmSymbolHandles::exit_method_name(),
1486 vmSymbolHandles::void_method_signature(),
1487 THREAD);
1488 CLEAR_PENDING_EXCEPTION;
1489 }
1490 }
1492 // notify JVMTI
1493 if (JvmtiExport::should_post_thread_life()) {
1494 JvmtiExport::post_thread_end(this);
1495 }
1497 // We have notified the agents that we are exiting, before we go on,
1498 // we must check for a pending external suspend request and honor it
1499 // in order to not surprise the thread that made the suspend request.
1500 while (true) {
1501 {
1502 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1503 if (!is_external_suspend()) {
1504 set_terminated(_thread_exiting);
1505 ThreadService::current_thread_exiting(this);
1506 break;
1507 }
1508 // Implied else:
1509 // Things get a little tricky here. We have a pending external
1510 // suspend request, but we are holding the SR_lock so we
1511 // can't just self-suspend. So we temporarily drop the lock
1512 // and then self-suspend.
1513 }
1515 ThreadBlockInVM tbivm(this);
1516 java_suspend_self();
1518 // We're done with this suspend request, but we have to loop around
1519 // and check again. Eventually we will get SR_lock without a pending
1520 // external suspend request and will be able to mark ourselves as
1521 // exiting.
1522 }
1523 // no more external suspends are allowed at this point
1524 } else {
1525 // before_exit() has already posted JVMTI THREAD_END events
1526 }
1528 // Notify waiters on thread object. This has to be done after exit() is called
1529 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1530 // group should have the destroyed bit set before waiters are notified).
1531 ensure_join(this);
1532 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1534 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1535 // held by this thread must be released. A detach operation must only
1536 // get here if there are no Java frames on the stack. Therefore, any
1537 // owned monitors at this point MUST be JNI-acquired monitors which are
1538 // pre-inflated and in the monitor cache.
1539 //
1540 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1541 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1542 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1543 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1544 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1545 }
1547 // These things needs to be done while we are still a Java Thread. Make sure that thread
1548 // is in a consistent state, in case GC happens
1549 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1551 if (active_handles() != NULL) {
1552 JNIHandleBlock* block = active_handles();
1553 set_active_handles(NULL);
1554 JNIHandleBlock::release_block(block);
1555 }
1557 if (free_handle_block() != NULL) {
1558 JNIHandleBlock* block = free_handle_block();
1559 set_free_handle_block(NULL);
1560 JNIHandleBlock::release_block(block);
1561 }
1563 // These have to be removed while this is still a valid thread.
1564 remove_stack_guard_pages();
1566 if (UseTLAB) {
1567 tlab().make_parsable(true); // retire TLAB
1568 }
1570 if (jvmti_thread_state() != NULL) {
1571 JvmtiExport::cleanup_thread(this);
1572 }
1574 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1575 Threads::remove(this);
1576 }
1578 void JavaThread::cleanup_failed_attach_current_thread() {
1580 if (get_thread_profiler() != NULL) {
1581 get_thread_profiler()->disengage();
1582 ResourceMark rm;
1583 get_thread_profiler()->print(get_thread_name());
1584 }
1586 if (active_handles() != NULL) {
1587 JNIHandleBlock* block = active_handles();
1588 set_active_handles(NULL);
1589 JNIHandleBlock::release_block(block);
1590 }
1592 if (free_handle_block() != NULL) {
1593 JNIHandleBlock* block = free_handle_block();
1594 set_free_handle_block(NULL);
1595 JNIHandleBlock::release_block(block);
1596 }
1598 if (UseTLAB) {
1599 tlab().make_parsable(true); // retire TLAB, if any
1600 }
1602 Threads::remove(this);
1603 delete this;
1604 }
1607 JavaThread* JavaThread::active() {
1608 Thread* thread = ThreadLocalStorage::thread();
1609 assert(thread != NULL, "just checking");
1610 if (thread->is_Java_thread()) {
1611 return (JavaThread*) thread;
1612 } else {
1613 assert(thread->is_VM_thread(), "this must be a vm thread");
1614 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1615 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1616 assert(ret->is_Java_thread(), "must be a Java thread");
1617 return ret;
1618 }
1619 }
1621 bool JavaThread::is_lock_owned(address adr) const {
1622 if (lock_is_in_stack(adr)) return true;
1624 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1625 if (chunk->contains(adr)) return true;
1626 }
1628 return false;
1629 }
1632 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1633 chunk->set_next(monitor_chunks());
1634 set_monitor_chunks(chunk);
1635 }
1637 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1638 guarantee(monitor_chunks() != NULL, "must be non empty");
1639 if (monitor_chunks() == chunk) {
1640 set_monitor_chunks(chunk->next());
1641 } else {
1642 MonitorChunk* prev = monitor_chunks();
1643 while (prev->next() != chunk) prev = prev->next();
1644 prev->set_next(chunk->next());
1645 }
1646 }
1648 // JVM support.
1650 // Note: this function shouldn't block if it's called in
1651 // _thread_in_native_trans state (such as from
1652 // check_special_condition_for_native_trans()).
1653 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1655 if (has_last_Java_frame() && has_async_condition()) {
1656 // If we are at a polling page safepoint (not a poll return)
1657 // then we must defer async exception because live registers
1658 // will be clobbered by the exception path. Poll return is
1659 // ok because the call we a returning from already collides
1660 // with exception handling registers and so there is no issue.
1661 // (The exception handling path kills call result registers but
1662 // this is ok since the exception kills the result anyway).
1664 if (is_at_poll_safepoint()) {
1665 // if the code we are returning to has deoptimized we must defer
1666 // the exception otherwise live registers get clobbered on the
1667 // exception path before deoptimization is able to retrieve them.
1668 //
1669 RegisterMap map(this, false);
1670 frame caller_fr = last_frame().sender(&map);
1671 assert(caller_fr.is_compiled_frame(), "what?");
1672 if (caller_fr.is_deoptimized_frame()) {
1673 if (TraceExceptions) {
1674 ResourceMark rm;
1675 tty->print_cr("deferred async exception at compiled safepoint");
1676 }
1677 return;
1678 }
1679 }
1680 }
1682 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
1683 if (condition == _no_async_condition) {
1684 // Conditions have changed since has_special_runtime_exit_condition()
1685 // was called:
1686 // - if we were here only because of an external suspend request,
1687 // then that was taken care of above (or cancelled) so we are done
1688 // - if we were here because of another async request, then it has
1689 // been cleared between the has_special_runtime_exit_condition()
1690 // and now so again we are done
1691 return;
1692 }
1694 // Check for pending async. exception
1695 if (_pending_async_exception != NULL) {
1696 // Only overwrite an already pending exception, if it is not a threadDeath.
1697 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::threaddeath_klass())) {
1699 // We cannot call Exceptions::_throw(...) here because we cannot block
1700 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
1702 if (TraceExceptions) {
1703 ResourceMark rm;
1704 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
1705 if (has_last_Java_frame() ) {
1706 frame f = last_frame();
1707 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
1708 }
1709 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1710 }
1711 _pending_async_exception = NULL;
1712 clear_has_async_exception();
1713 }
1714 }
1716 if (check_unsafe_error &&
1717 condition == _async_unsafe_access_error && !has_pending_exception()) {
1718 condition = _no_async_condition; // done
1719 switch (thread_state()) {
1720 case _thread_in_vm:
1721 {
1722 JavaThread* THREAD = this;
1723 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1724 }
1725 case _thread_in_native:
1726 {
1727 ThreadInVMfromNative tiv(this);
1728 JavaThread* THREAD = this;
1729 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1730 }
1731 case _thread_in_Java:
1732 {
1733 ThreadInVMfromJava tiv(this);
1734 JavaThread* THREAD = this;
1735 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
1736 }
1737 default:
1738 ShouldNotReachHere();
1739 }
1740 }
1742 assert(condition == _no_async_condition || has_pending_exception() ||
1743 (!check_unsafe_error && condition == _async_unsafe_access_error),
1744 "must have handled the async condition, if no exception");
1745 }
1747 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
1748 //
1749 // Check for pending external suspend. Internal suspend requests do
1750 // not use handle_special_runtime_exit_condition().
1751 // If JNIEnv proxies are allowed, don't self-suspend if the target
1752 // thread is not the current thread. In older versions of jdbx, jdbx
1753 // threads could call into the VM with another thread's JNIEnv so we
1754 // can be here operating on behalf of a suspended thread (4432884).
1755 bool do_self_suspend = is_external_suspend_with_lock();
1756 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
1757 //
1758 // Because thread is external suspended the safepoint code will count
1759 // thread as at a safepoint. This can be odd because we can be here
1760 // as _thread_in_Java which would normally transition to _thread_blocked
1761 // at a safepoint. We would like to mark the thread as _thread_blocked
1762 // before calling java_suspend_self like all other callers of it but
1763 // we must then observe proper safepoint protocol. (We can't leave
1764 // _thread_blocked with a safepoint in progress). However we can be
1765 // here as _thread_in_native_trans so we can't use a normal transition
1766 // constructor/destructor pair because they assert on that type of
1767 // transition. We could do something like:
1768 //
1769 // JavaThreadState state = thread_state();
1770 // set_thread_state(_thread_in_vm);
1771 // {
1772 // ThreadBlockInVM tbivm(this);
1773 // java_suspend_self()
1774 // }
1775 // set_thread_state(_thread_in_vm_trans);
1776 // if (safepoint) block;
1777 // set_thread_state(state);
1778 //
1779 // but that is pretty messy. Instead we just go with the way the
1780 // code has worked before and note that this is the only path to
1781 // java_suspend_self that doesn't put the thread in _thread_blocked
1782 // mode.
1784 frame_anchor()->make_walkable(this);
1785 java_suspend_self();
1787 // We might be here for reasons in addition to the self-suspend request
1788 // so check for other async requests.
1789 }
1791 if (check_asyncs) {
1792 check_and_handle_async_exceptions();
1793 }
1794 }
1796 void JavaThread::send_thread_stop(oop java_throwable) {
1797 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
1798 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
1799 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
1801 // Do not throw asynchronous exceptions against the compiler thread
1802 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
1803 if (is_Compiler_thread()) return;
1805 // This is a change from JDK 1.1, but JDK 1.2 will also do it:
1806 if (java_throwable->is_a(SystemDictionary::threaddeath_klass())) {
1807 java_lang_Thread::set_stillborn(threadObj());
1808 }
1810 {
1811 // Actually throw the Throwable against the target Thread - however
1812 // only if there is no thread death exception installed already.
1813 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::threaddeath_klass())) {
1814 // If the topmost frame is a runtime stub, then we are calling into
1815 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1816 // must deoptimize the caller before continuing, as the compiled exception handler table
1817 // may not be valid
1818 if (has_last_Java_frame()) {
1819 frame f = last_frame();
1820 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
1821 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
1822 RegisterMap reg_map(this, UseBiasedLocking);
1823 frame compiled_frame = f.sender(®_map);
1824 if (compiled_frame.can_be_deoptimized()) {
1825 Deoptimization::deoptimize(this, compiled_frame, ®_map);
1826 }
1827 }
1828 }
1830 // Set async. pending exception in thread.
1831 set_pending_async_exception(java_throwable);
1833 if (TraceExceptions) {
1834 ResourceMark rm;
1835 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1836 }
1837 // for AbortVMOnException flag
1838 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
1839 }
1840 }
1843 // Interrupt thread so it will wake up from a potential wait()
1844 Thread::interrupt(this);
1845 }
1847 // External suspension mechanism.
1848 //
1849 // Tell the VM to suspend a thread when ever it knows that it does not hold on
1850 // to any VM_locks and it is at a transition
1851 // Self-suspension will happen on the transition out of the vm.
1852 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
1853 //
1854 // Guarantees on return:
1855 // + Target thread will not execute any new bytecode (that's why we need to
1856 // force a safepoint)
1857 // + Target thread will not enter any new monitors
1858 //
1859 void JavaThread::java_suspend() {
1860 { MutexLocker mu(Threads_lock);
1861 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
1862 return;
1863 }
1864 }
1866 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1867 if (!is_external_suspend()) {
1868 // a racing resume has cancelled us; bail out now
1869 return;
1870 }
1872 // suspend is done
1873 uint32_t debug_bits = 0;
1874 // Warning: is_ext_suspend_completed() may temporarily drop the
1875 // SR_lock to allow the thread to reach a stable thread state if
1876 // it is currently in a transient thread state.
1877 if (is_ext_suspend_completed(false /* !called_by_wait */,
1878 SuspendRetryDelay, &debug_bits) ) {
1879 return;
1880 }
1881 }
1883 VM_ForceSafepoint vm_suspend;
1884 VMThread::execute(&vm_suspend);
1885 }
1887 // Part II of external suspension.
1888 // A JavaThread self suspends when it detects a pending external suspend
1889 // request. This is usually on transitions. It is also done in places
1890 // where continuing to the next transition would surprise the caller,
1891 // e.g., monitor entry.
1892 //
1893 // Returns the number of times that the thread self-suspended.
1894 //
1895 // Note: DO NOT call java_suspend_self() when you just want to block current
1896 // thread. java_suspend_self() is the second stage of cooperative
1897 // suspension for external suspend requests and should only be used
1898 // to complete an external suspend request.
1899 //
1900 int JavaThread::java_suspend_self() {
1901 int ret = 0;
1903 // we are in the process of exiting so don't suspend
1904 if (is_exiting()) {
1905 clear_external_suspend();
1906 return ret;
1907 }
1909 assert(_anchor.walkable() ||
1910 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
1911 "must have walkable stack");
1913 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1915 assert(!this->is_any_suspended(),
1916 "a thread trying to self-suspend should not already be suspended");
1918 if (this->is_suspend_equivalent()) {
1919 // If we are self-suspending as a result of the lifting of a
1920 // suspend equivalent condition, then the suspend_equivalent
1921 // flag is not cleared until we set the ext_suspended flag so
1922 // that wait_for_ext_suspend_completion() returns consistent
1923 // results.
1924 this->clear_suspend_equivalent();
1925 }
1927 // A racing resume may have cancelled us before we grabbed SR_lock
1928 // above. Or another external suspend request could be waiting for us
1929 // by the time we return from SR_lock()->wait(). The thread
1930 // that requested the suspension may already be trying to walk our
1931 // stack and if we return now, we can change the stack out from under
1932 // it. This would be a "bad thing (TM)" and cause the stack walker
1933 // to crash. We stay self-suspended until there are no more pending
1934 // external suspend requests.
1935 while (is_external_suspend()) {
1936 ret++;
1937 this->set_ext_suspended();
1939 // _ext_suspended flag is cleared by java_resume()
1940 while (is_ext_suspended()) {
1941 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
1942 }
1943 }
1945 return ret;
1946 }
1948 #ifdef ASSERT
1949 // verify the JavaThread has not yet been published in the Threads::list, and
1950 // hence doesn't need protection from concurrent access at this stage
1951 void JavaThread::verify_not_published() {
1952 if (!Threads_lock->owned_by_self()) {
1953 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
1954 assert( !Threads::includes(this),
1955 "java thread shouldn't have been published yet!");
1956 }
1957 else {
1958 assert( !Threads::includes(this),
1959 "java thread shouldn't have been published yet!");
1960 }
1961 }
1962 #endif
1964 // Slow path when the native==>VM/Java barriers detect a safepoint is in
1965 // progress or when _suspend_flags is non-zero.
1966 // Current thread needs to self-suspend if there is a suspend request and/or
1967 // block if a safepoint is in progress.
1968 // Async exception ISN'T checked.
1969 // Note only the ThreadInVMfromNative transition can call this function
1970 // directly and when thread state is _thread_in_native_trans
1971 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
1972 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1974 JavaThread *curJT = JavaThread::current();
1975 bool do_self_suspend = thread->is_external_suspend();
1977 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
1979 // If JNIEnv proxies are allowed, don't self-suspend if the target
1980 // thread is not the current thread. In older versions of jdbx, jdbx
1981 // threads could call into the VM with another thread's JNIEnv so we
1982 // can be here operating on behalf of a suspended thread (4432884).
1983 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
1984 JavaThreadState state = thread->thread_state();
1986 // We mark this thread_blocked state as a suspend-equivalent so
1987 // that a caller to is_ext_suspend_completed() won't be confused.
1988 // The suspend-equivalent state is cleared by java_suspend_self().
1989 thread->set_suspend_equivalent();
1991 // If the safepoint code sees the _thread_in_native_trans state, it will
1992 // wait until the thread changes to other thread state. There is no
1993 // guarantee on how soon we can obtain the SR_lock and complete the
1994 // self-suspend request. It would be a bad idea to let safepoint wait for
1995 // too long. Temporarily change the state to _thread_blocked to
1996 // let the VM thread know that this thread is ready for GC. The problem
1997 // of changing thread state is that safepoint could happen just after
1998 // java_suspend_self() returns after being resumed, and VM thread will
1999 // see the _thread_blocked state. We must check for safepoint
2000 // after restoring the state and make sure we won't leave while a safepoint
2001 // is in progress.
2002 thread->set_thread_state(_thread_blocked);
2003 thread->java_suspend_self();
2004 thread->set_thread_state(state);
2005 // Make sure new state is seen by VM thread
2006 if (os::is_MP()) {
2007 if (UseMembar) {
2008 // Force a fence between the write above and read below
2009 OrderAccess::fence();
2010 } else {
2011 // Must use this rather than serialization page in particular on Windows
2012 InterfaceSupport::serialize_memory(thread);
2013 }
2014 }
2015 }
2017 if (SafepointSynchronize::do_call_back()) {
2018 // If we are safepointing, then block the caller which may not be
2019 // the same as the target thread (see above).
2020 SafepointSynchronize::block(curJT);
2021 }
2023 if (thread->is_deopt_suspend()) {
2024 thread->clear_deopt_suspend();
2025 RegisterMap map(thread, false);
2026 frame f = thread->last_frame();
2027 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2028 f = f.sender(&map);
2029 }
2030 if (f.id() == thread->must_deopt_id()) {
2031 thread->clear_must_deopt_id();
2032 // Since we know we're safe to deopt the current state is a safe state
2033 f.deoptimize(thread, true);
2034 } else {
2035 fatal("missed deoptimization!");
2036 }
2037 }
2038 }
2040 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2041 // progress or when _suspend_flags is non-zero.
2042 // Current thread needs to self-suspend if there is a suspend request and/or
2043 // block if a safepoint is in progress.
2044 // Also check for pending async exception (not including unsafe access error).
2045 // Note only the native==>VM/Java barriers can call this function and when
2046 // thread state is _thread_in_native_trans.
2047 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2048 check_safepoint_and_suspend_for_native_trans(thread);
2050 if (thread->has_async_exception()) {
2051 // We are in _thread_in_native_trans state, don't handle unsafe
2052 // access error since that may block.
2053 thread->check_and_handle_async_exceptions(false);
2054 }
2055 }
2057 // We need to guarantee the Threads_lock here, since resumes are not
2058 // allowed during safepoint synchronization
2059 // Can only resume from an external suspension
2060 void JavaThread::java_resume() {
2061 assert_locked_or_safepoint(Threads_lock);
2063 // Sanity check: thread is gone, has started exiting or the thread
2064 // was not externally suspended.
2065 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2066 return;
2067 }
2069 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2071 clear_external_suspend();
2073 if (is_ext_suspended()) {
2074 clear_ext_suspended();
2075 SR_lock()->notify_all();
2076 }
2077 }
2079 void JavaThread::create_stack_guard_pages() {
2080 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2081 address low_addr = stack_base() - stack_size();
2082 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2084 int allocate = os::allocate_stack_guard_pages();
2085 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2087 if (allocate && !os::commit_memory((char *) low_addr, len)) {
2088 warning("Attempt to allocate stack guard pages failed.");
2089 return;
2090 }
2092 if (os::guard_memory((char *) low_addr, len)) {
2093 _stack_guard_state = stack_guard_enabled;
2094 } else {
2095 warning("Attempt to protect stack guard pages failed.");
2096 if (os::uncommit_memory((char *) low_addr, len)) {
2097 warning("Attempt to deallocate stack guard pages failed.");
2098 }
2099 }
2100 }
2102 void JavaThread::remove_stack_guard_pages() {
2103 if (_stack_guard_state == stack_guard_unused) return;
2104 address low_addr = stack_base() - stack_size();
2105 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2107 if (os::allocate_stack_guard_pages()) {
2108 if (os::uncommit_memory((char *) low_addr, len)) {
2109 _stack_guard_state = stack_guard_unused;
2110 } else {
2111 warning("Attempt to deallocate stack guard pages failed.");
2112 }
2113 } else {
2114 if (_stack_guard_state == stack_guard_unused) return;
2115 if (os::unguard_memory((char *) low_addr, len)) {
2116 _stack_guard_state = stack_guard_unused;
2117 } else {
2118 warning("Attempt to unprotect stack guard pages failed.");
2119 }
2120 }
2121 }
2123 void JavaThread::enable_stack_yellow_zone() {
2124 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2125 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2127 // The base notation is from the stacks point of view, growing downward.
2128 // We need to adjust it to work correctly with guard_memory()
2129 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2131 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2132 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2134 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2135 _stack_guard_state = stack_guard_enabled;
2136 } else {
2137 warning("Attempt to guard stack yellow zone failed.");
2138 }
2139 enable_register_stack_guard();
2140 }
2142 void JavaThread::disable_stack_yellow_zone() {
2143 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2144 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2146 // Simply return if called for a thread that does not use guard pages.
2147 if (_stack_guard_state == stack_guard_unused) return;
2149 // The base notation is from the stacks point of view, growing downward.
2150 // We need to adjust it to work correctly with guard_memory()
2151 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2153 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2154 _stack_guard_state = stack_guard_yellow_disabled;
2155 } else {
2156 warning("Attempt to unguard stack yellow zone failed.");
2157 }
2158 disable_register_stack_guard();
2159 }
2161 void JavaThread::enable_stack_red_zone() {
2162 // The base notation is from the stacks point of view, growing downward.
2163 // We need to adjust it to work correctly with guard_memory()
2164 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2165 address base = stack_red_zone_base() - stack_red_zone_size();
2167 guarantee(base < stack_base(),"Error calculating stack red zone");
2168 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2170 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2171 warning("Attempt to guard stack red zone failed.");
2172 }
2173 }
2175 void JavaThread::disable_stack_red_zone() {
2176 // The base notation is from the stacks point of view, growing downward.
2177 // We need to adjust it to work correctly with guard_memory()
2178 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2179 address base = stack_red_zone_base() - stack_red_zone_size();
2180 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2181 warning("Attempt to unguard stack red zone failed.");
2182 }
2183 }
2185 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2186 // ignore is there is no stack
2187 if (!has_last_Java_frame()) return;
2188 // traverse the stack frames. Starts from top frame.
2189 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2190 frame* fr = fst.current();
2191 f(fr, fst.register_map());
2192 }
2193 }
2196 #ifndef PRODUCT
2197 // Deoptimization
2198 // Function for testing deoptimization
2199 void JavaThread::deoptimize() {
2200 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2201 StackFrameStream fst(this, UseBiasedLocking);
2202 bool deopt = false; // Dump stack only if a deopt actually happens.
2203 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2204 // Iterate over all frames in the thread and deoptimize
2205 for(; !fst.is_done(); fst.next()) {
2206 if(fst.current()->can_be_deoptimized()) {
2208 if (only_at) {
2209 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2210 // consists of comma or carriage return separated numbers so
2211 // search for the current bci in that string.
2212 address pc = fst.current()->pc();
2213 nmethod* nm = (nmethod*) fst.current()->cb();
2214 ScopeDesc* sd = nm->scope_desc_at( pc);
2215 char buffer[8];
2216 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2217 size_t len = strlen(buffer);
2218 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2219 while (found != NULL) {
2220 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2221 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2222 // Check that the bci found is bracketed by terminators.
2223 break;
2224 }
2225 found = strstr(found + 1, buffer);
2226 }
2227 if (!found) {
2228 continue;
2229 }
2230 }
2232 if (DebugDeoptimization && !deopt) {
2233 deopt = true; // One-time only print before deopt
2234 tty->print_cr("[BEFORE Deoptimization]");
2235 trace_frames();
2236 trace_stack();
2237 }
2238 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2239 }
2240 }
2242 if (DebugDeoptimization && deopt) {
2243 tty->print_cr("[AFTER Deoptimization]");
2244 trace_frames();
2245 }
2246 }
2249 // Make zombies
2250 void JavaThread::make_zombies() {
2251 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2252 if (fst.current()->can_be_deoptimized()) {
2253 // it is a Java nmethod
2254 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2255 nm->make_not_entrant();
2256 }
2257 }
2258 }
2259 #endif // PRODUCT
2262 void JavaThread::deoptimized_wrt_marked_nmethods() {
2263 if (!has_last_Java_frame()) return;
2264 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2265 StackFrameStream fst(this, UseBiasedLocking);
2266 for(; !fst.is_done(); fst.next()) {
2267 if (fst.current()->should_be_deoptimized()) {
2268 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2269 }
2270 }
2271 }
2274 // GC support
2275 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2277 void JavaThread::gc_epilogue() {
2278 frames_do(frame_gc_epilogue);
2279 }
2282 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2284 void JavaThread::gc_prologue() {
2285 frames_do(frame_gc_prologue);
2286 }
2289 void JavaThread::oops_do(OopClosure* f) {
2290 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2291 // since there may be more than one thread using each ThreadProfiler.
2293 // Traverse the GCHandles
2294 Thread::oops_do(f);
2296 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2297 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2299 if (has_last_Java_frame()) {
2301 // Traverse the privileged stack
2302 if (_privileged_stack_top != NULL) {
2303 _privileged_stack_top->oops_do(f);
2304 }
2306 // traverse the registered growable array
2307 if (_array_for_gc != NULL) {
2308 for (int index = 0; index < _array_for_gc->length(); index++) {
2309 f->do_oop(_array_for_gc->adr_at(index));
2310 }
2311 }
2313 // Traverse the monitor chunks
2314 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2315 chunk->oops_do(f);
2316 }
2318 // Traverse the execution stack
2319 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2320 fst.current()->oops_do(f, fst.register_map());
2321 }
2322 }
2324 // callee_target is never live across a gc point so NULL it here should
2325 // it still contain a methdOop.
2327 set_callee_target(NULL);
2329 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2330 // If we have deferred set_locals there might be oops waiting to be
2331 // written
2332 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2333 if (list != NULL) {
2334 for (int i = 0; i < list->length(); i++) {
2335 list->at(i)->oops_do(f);
2336 }
2337 }
2339 // Traverse instance variables at the end since the GC may be moving things
2340 // around using this function
2341 f->do_oop((oop*) &_threadObj);
2342 f->do_oop((oop*) &_vm_result);
2343 f->do_oop((oop*) &_vm_result_2);
2344 f->do_oop((oop*) &_exception_oop);
2345 f->do_oop((oop*) &_pending_async_exception);
2347 if (jvmti_thread_state() != NULL) {
2348 jvmti_thread_state()->oops_do(f);
2349 }
2350 }
2352 void JavaThread::nmethods_do() {
2353 // Traverse the GCHandles
2354 Thread::nmethods_do();
2356 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2357 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2359 if (has_last_Java_frame()) {
2360 // Traverse the execution stack
2361 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2362 fst.current()->nmethods_do();
2363 }
2364 }
2365 }
2367 // Printing
2368 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2369 switch (_thread_state) {
2370 case _thread_uninitialized: return "_thread_uninitialized";
2371 case _thread_new: return "_thread_new";
2372 case _thread_new_trans: return "_thread_new_trans";
2373 case _thread_in_native: return "_thread_in_native";
2374 case _thread_in_native_trans: return "_thread_in_native_trans";
2375 case _thread_in_vm: return "_thread_in_vm";
2376 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2377 case _thread_in_Java: return "_thread_in_Java";
2378 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2379 case _thread_blocked: return "_thread_blocked";
2380 case _thread_blocked_trans: return "_thread_blocked_trans";
2381 default: return "unknown thread state";
2382 }
2383 }
2385 #ifndef PRODUCT
2386 void JavaThread::print_thread_state_on(outputStream *st) const {
2387 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2388 };
2389 void JavaThread::print_thread_state() const {
2390 print_thread_state_on(tty);
2391 };
2392 #endif // PRODUCT
2394 // Called by Threads::print() for VM_PrintThreads operation
2395 void JavaThread::print_on(outputStream *st) const {
2396 st->print("\"%s\" ", get_thread_name());
2397 oop thread_oop = threadObj();
2398 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2399 Thread::print_on(st);
2400 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2401 st->print_cr("[" INTPTR_FORMAT ".." INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12), highest_lock());
2402 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2403 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2404 }
2405 #ifndef PRODUCT
2406 print_thread_state_on(st);
2407 _safepoint_state->print_on(st);
2408 #endif // PRODUCT
2409 }
2411 // Called by fatal error handler. The difference between this and
2412 // JavaThread::print() is that we can't grab lock or allocate memory.
2413 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2414 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2415 oop thread_obj = threadObj();
2416 if (thread_obj != NULL) {
2417 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2418 }
2419 st->print(" [");
2420 st->print("%s", _get_thread_state_name(_thread_state));
2421 if (osthread()) {
2422 st->print(", id=%d", osthread()->thread_id());
2423 }
2424 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2425 _stack_base - _stack_size, _stack_base);
2426 st->print("]");
2427 return;
2428 }
2430 // Verification
2432 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2434 void JavaThread::verify() {
2435 // Verify oops in the thread.
2436 oops_do(&VerifyOopClosure::verify_oop);
2438 // Verify the stack frames.
2439 frames_do(frame_verify);
2440 }
2442 // CR 6300358 (sub-CR 2137150)
2443 // Most callers of this method assume that it can't return NULL but a
2444 // thread may not have a name whilst it is in the process of attaching to
2445 // the VM - see CR 6412693, and there are places where a JavaThread can be
2446 // seen prior to having it's threadObj set (eg JNI attaching threads and
2447 // if vm exit occurs during initialization). These cases can all be accounted
2448 // for such that this method never returns NULL.
2449 const char* JavaThread::get_thread_name() const {
2450 #ifdef ASSERT
2451 // early safepoints can hit while current thread does not yet have TLS
2452 if (!SafepointSynchronize::is_at_safepoint()) {
2453 Thread *cur = Thread::current();
2454 if (!(cur->is_Java_thread() && cur == this)) {
2455 // Current JavaThreads are allowed to get their own name without
2456 // the Threads_lock.
2457 assert_locked_or_safepoint(Threads_lock);
2458 }
2459 }
2460 #endif // ASSERT
2461 return get_thread_name_string();
2462 }
2464 // Returns a non-NULL representation of this thread's name, or a suitable
2465 // descriptive string if there is no set name
2466 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2467 const char* name_str;
2468 oop thread_obj = threadObj();
2469 if (thread_obj != NULL) {
2470 typeArrayOop name = java_lang_Thread::name(thread_obj);
2471 if (name != NULL) {
2472 if (buf == NULL) {
2473 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2474 }
2475 else {
2476 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2477 }
2478 }
2479 else if (is_attaching()) { // workaround for 6412693 - see 6404306
2480 name_str = "<no-name - thread is attaching>";
2481 }
2482 else {
2483 name_str = Thread::name();
2484 }
2485 }
2486 else {
2487 name_str = Thread::name();
2488 }
2489 assert(name_str != NULL, "unexpected NULL thread name");
2490 return name_str;
2491 }
2494 const char* JavaThread::get_threadgroup_name() const {
2495 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2496 oop thread_obj = threadObj();
2497 if (thread_obj != NULL) {
2498 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2499 if (thread_group != NULL) {
2500 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2501 // ThreadGroup.name can be null
2502 if (name != NULL) {
2503 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2504 return str;
2505 }
2506 }
2507 }
2508 return NULL;
2509 }
2511 const char* JavaThread::get_parent_name() const {
2512 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2513 oop thread_obj = threadObj();
2514 if (thread_obj != NULL) {
2515 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2516 if (thread_group != NULL) {
2517 oop parent = java_lang_ThreadGroup::parent(thread_group);
2518 if (parent != NULL) {
2519 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2520 // ThreadGroup.name can be null
2521 if (name != NULL) {
2522 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2523 return str;
2524 }
2525 }
2526 }
2527 }
2528 return NULL;
2529 }
2531 ThreadPriority JavaThread::java_priority() const {
2532 oop thr_oop = threadObj();
2533 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2534 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2535 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2536 return priority;
2537 }
2539 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2541 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2542 // Link Java Thread object <-> C++ Thread
2544 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2545 // and put it into a new Handle. The Handle "thread_oop" can then
2546 // be used to pass the C++ thread object to other methods.
2548 // Set the Java level thread object (jthread) field of the
2549 // new thread (a JavaThread *) to C++ thread object using the
2550 // "thread_oop" handle.
2552 // Set the thread field (a JavaThread *) of the
2553 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2555 Handle thread_oop(Thread::current(),
2556 JNIHandles::resolve_non_null(jni_thread));
2557 assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
2558 "must be initialized");
2559 set_threadObj(thread_oop());
2560 java_lang_Thread::set_thread(thread_oop(), this);
2562 if (prio == NoPriority) {
2563 prio = java_lang_Thread::priority(thread_oop());
2564 assert(prio != NoPriority, "A valid priority should be present");
2565 }
2567 // Push the Java priority down to the native thread; needs Threads_lock
2568 Thread::set_priority(this, prio);
2570 // Add the new thread to the Threads list and set it in motion.
2571 // We must have threads lock in order to call Threads::add.
2572 // It is crucial that we do not block before the thread is
2573 // added to the Threads list for if a GC happens, then the java_thread oop
2574 // will not be visited by GC.
2575 Threads::add(this);
2576 }
2578 oop JavaThread::current_park_blocker() {
2579 // Support for JSR-166 locks
2580 oop thread_oop = threadObj();
2581 if (thread_oop != NULL && JDK_Version::supports_thread_park_blocker()) {
2582 return java_lang_Thread::park_blocker(thread_oop);
2583 }
2584 return NULL;
2585 }
2588 void JavaThread::print_stack_on(outputStream* st) {
2589 if (!has_last_Java_frame()) return;
2590 ResourceMark rm;
2591 HandleMark hm;
2593 RegisterMap reg_map(this);
2594 vframe* start_vf = last_java_vframe(®_map);
2595 int count = 0;
2596 for (vframe* f = start_vf; f; f = f->sender() ) {
2597 if (f->is_java_frame()) {
2598 javaVFrame* jvf = javaVFrame::cast(f);
2599 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2601 // Print out lock information
2602 if (JavaMonitorsInStackTrace) {
2603 jvf->print_lock_info_on(st, count);
2604 }
2605 } else {
2606 // Ignore non-Java frames
2607 }
2609 // Bail-out case for too deep stacks
2610 count++;
2611 if (MaxJavaStackTraceDepth == count) return;
2612 }
2613 }
2616 // JVMTI PopFrame support
2617 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2618 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2619 if (in_bytes(size_in_bytes) != 0) {
2620 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes));
2621 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2622 Copy::conjoint_bytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2623 }
2624 }
2626 void* JavaThread::popframe_preserved_args() {
2627 return _popframe_preserved_args;
2628 }
2630 ByteSize JavaThread::popframe_preserved_args_size() {
2631 return in_ByteSize(_popframe_preserved_args_size);
2632 }
2634 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2635 int sz = in_bytes(popframe_preserved_args_size());
2636 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2637 return in_WordSize(sz / wordSize);
2638 }
2640 void JavaThread::popframe_free_preserved_args() {
2641 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2642 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
2643 _popframe_preserved_args = NULL;
2644 _popframe_preserved_args_size = 0;
2645 }
2647 #ifndef PRODUCT
2649 void JavaThread::trace_frames() {
2650 tty->print_cr("[Describe stack]");
2651 int frame_no = 1;
2652 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2653 tty->print(" %d. ", frame_no++);
2654 fst.current()->print_value_on(tty,this);
2655 tty->cr();
2656 }
2657 }
2660 void JavaThread::trace_stack_from(vframe* start_vf) {
2661 ResourceMark rm;
2662 int vframe_no = 1;
2663 for (vframe* f = start_vf; f; f = f->sender() ) {
2664 if (f->is_java_frame()) {
2665 javaVFrame::cast(f)->print_activation(vframe_no++);
2666 } else {
2667 f->print();
2668 }
2669 if (vframe_no > StackPrintLimit) {
2670 tty->print_cr("...<more frames>...");
2671 return;
2672 }
2673 }
2674 }
2677 void JavaThread::trace_stack() {
2678 if (!has_last_Java_frame()) return;
2679 ResourceMark rm;
2680 HandleMark hm;
2681 RegisterMap reg_map(this);
2682 trace_stack_from(last_java_vframe(®_map));
2683 }
2686 #endif // PRODUCT
2689 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2690 assert(reg_map != NULL, "a map must be given");
2691 frame f = last_frame();
2692 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
2693 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2694 }
2695 return NULL;
2696 }
2699 klassOop JavaThread::security_get_caller_class(int depth) {
2700 vframeStream vfst(this);
2701 vfst.security_get_caller_frame(depth);
2702 if (!vfst.at_end()) {
2703 return vfst.method()->method_holder();
2704 }
2705 return NULL;
2706 }
2708 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
2709 assert(thread->is_Compiler_thread(), "must be compiler thread");
2710 CompileBroker::compiler_thread_loop();
2711 }
2713 // Create a CompilerThread
2714 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
2715 : JavaThread(&compiler_thread_entry) {
2716 _env = NULL;
2717 _log = NULL;
2718 _task = NULL;
2719 _queue = queue;
2720 _counters = counters;
2722 #ifndef PRODUCT
2723 _ideal_graph_printer = NULL;
2724 #endif
2725 }
2728 // ======= Threads ========
2730 // The Threads class links together all active threads, and provides
2731 // operations over all threads. It is protected by its own Mutex
2732 // lock, which is also used in other contexts to protect thread
2733 // operations from having the thread being operated on from exiting
2734 // and going away unexpectedly (e.g., safepoint synchronization)
2736 JavaThread* Threads::_thread_list = NULL;
2737 int Threads::_number_of_threads = 0;
2738 int Threads::_number_of_non_daemon_threads = 0;
2739 int Threads::_return_code = 0;
2740 size_t JavaThread::_stack_size_at_create = 0;
2742 // All JavaThreads
2743 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
2745 void os_stream();
2747 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
2748 void Threads::threads_do(ThreadClosure* tc) {
2749 assert_locked_or_safepoint(Threads_lock);
2750 // ALL_JAVA_THREADS iterates through all JavaThreads
2751 ALL_JAVA_THREADS(p) {
2752 tc->do_thread(p);
2753 }
2754 // Someday we could have a table or list of all non-JavaThreads.
2755 // For now, just manually iterate through them.
2756 tc->do_thread(VMThread::vm_thread());
2757 Universe::heap()->gc_threads_do(tc);
2758 tc->do_thread(WatcherThread::watcher_thread());
2759 // If CompilerThreads ever become non-JavaThreads, add them here
2760 }
2762 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
2764 // Check version
2765 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
2767 // Initialize the output stream module
2768 ostream_init();
2770 // Process java launcher properties.
2771 Arguments::process_sun_java_launcher_properties(args);
2773 // Initialize the os module before using TLS
2774 os::init();
2776 // Initialize system properties.
2777 Arguments::init_system_properties();
2779 // Parse arguments
2780 jint parse_result = Arguments::parse(args);
2781 if (parse_result != JNI_OK) return parse_result;
2783 if (PauseAtStartup) {
2784 os::pause();
2785 }
2787 HS_DTRACE_PROBE(hotspot, vm__init__begin);
2789 // Record VM creation timing statistics
2790 TraceVmCreationTime create_vm_timer;
2791 create_vm_timer.start();
2793 // Timing (must come after argument parsing)
2794 TraceTime timer("Create VM", TraceStartupTime);
2796 // Initialize the os module after parsing the args
2797 jint os_init_2_result = os::init_2();
2798 if (os_init_2_result != JNI_OK) return os_init_2_result;
2800 // Initialize output stream logging
2801 ostream_init_log();
2803 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
2804 // Must be before create_vm_init_agents()
2805 if (Arguments::init_libraries_at_startup()) {
2806 convert_vm_init_libraries_to_agents();
2807 }
2809 // Launch -agentlib/-agentpath and converted -Xrun agents
2810 if (Arguments::init_agents_at_startup()) {
2811 create_vm_init_agents();
2812 }
2814 // Initialize Threads state
2815 _thread_list = NULL;
2816 _number_of_threads = 0;
2817 _number_of_non_daemon_threads = 0;
2819 // Initialize TLS
2820 ThreadLocalStorage::init();
2822 // Initialize global data structures and create system classes in heap
2823 vm_init_globals();
2825 // Attach the main thread to this os thread
2826 JavaThread* main_thread = new JavaThread();
2827 main_thread->set_thread_state(_thread_in_vm);
2828 // must do this before set_active_handles and initialize_thread_local_storage
2829 // Note: on solaris initialize_thread_local_storage() will (indirectly)
2830 // change the stack size recorded here to one based on the java thread
2831 // stacksize. This adjusted size is what is used to figure the placement
2832 // of the guard pages.
2833 main_thread->record_stack_base_and_size();
2834 main_thread->initialize_thread_local_storage();
2836 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
2838 if (!main_thread->set_as_starting_thread()) {
2839 vm_shutdown_during_initialization(
2840 "Failed necessary internal allocation. Out of swap space");
2841 delete main_thread;
2842 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2843 return JNI_ENOMEM;
2844 }
2846 // Enable guard page *after* os::create_main_thread(), otherwise it would
2847 // crash Linux VM, see notes in os_linux.cpp.
2848 main_thread->create_stack_guard_pages();
2850 // Initialize Java-Leve synchronization subsystem
2851 ObjectSynchronizer::Initialize() ;
2853 // Initialize global modules
2854 jint status = init_globals();
2855 if (status != JNI_OK) {
2856 delete main_thread;
2857 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2858 return status;
2859 }
2861 HandleMark hm;
2863 { MutexLocker mu(Threads_lock);
2864 Threads::add(main_thread);
2865 }
2867 // Any JVMTI raw monitors entered in onload will transition into
2868 // real raw monitor. VM is setup enough here for raw monitor enter.
2869 JvmtiExport::transition_pending_onload_raw_monitors();
2871 if (VerifyBeforeGC &&
2872 Universe::heap()->total_collections() >= VerifyGCStartAt) {
2873 Universe::heap()->prepare_for_verify();
2874 Universe::verify(); // make sure we're starting with a clean slate
2875 }
2877 // Create the VMThread
2878 { TraceTime timer("Start VMThread", TraceStartupTime);
2879 VMThread::create();
2880 Thread* vmthread = VMThread::vm_thread();
2882 if (!os::create_thread(vmthread, os::vm_thread))
2883 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
2885 // Wait for the VM thread to become ready, and VMThread::run to initialize
2886 // Monitors can have spurious returns, must always check another state flag
2887 {
2888 MutexLocker ml(Notify_lock);
2889 os::start_thread(vmthread);
2890 while (vmthread->active_handles() == NULL) {
2891 Notify_lock->wait();
2892 }
2893 }
2894 }
2896 assert (Universe::is_fully_initialized(), "not initialized");
2897 EXCEPTION_MARK;
2899 // At this point, the Universe is initialized, but we have not executed
2900 // any byte code. Now is a good time (the only time) to dump out the
2901 // internal state of the JVM for sharing.
2903 if (DumpSharedSpaces) {
2904 Universe::heap()->preload_and_dump(CHECK_0);
2905 ShouldNotReachHere();
2906 }
2908 // Always call even when there are not JVMTI environments yet, since environments
2909 // may be attached late and JVMTI must track phases of VM execution
2910 JvmtiExport::enter_start_phase();
2912 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
2913 JvmtiExport::post_vm_start();
2915 {
2916 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
2918 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
2919 create_vm_init_libraries();
2920 }
2922 if (InitializeJavaLangString) {
2923 initialize_class(vmSymbolHandles::java_lang_String(), CHECK_0);
2924 } else {
2925 warning("java.lang.String not initialized");
2926 }
2928 if (AggressiveOpts) {
2929 {
2930 // Forcibly initialize java/util/HashMap and mutate the private
2931 // static final "frontCacheEnabled" field before we start creating instances
2932 #ifdef ASSERT
2933 klassOop tmp_k = SystemDictionary::find(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0);
2934 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
2935 #endif
2936 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0);
2937 KlassHandle k = KlassHandle(THREAD, k_o);
2938 guarantee(k.not_null(), "Must find java/util/HashMap");
2939 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
2940 ik->initialize(CHECK_0);
2941 fieldDescriptor fd;
2942 // Possible we might not find this field; if so, don't break
2943 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
2944 k()->bool_field_put(fd.offset(), true);
2945 }
2946 }
2948 if (UseStringCache) {
2949 // Forcibly initialize java/lang/String and mutate the private
2950 // static final "stringCacheEnabled" field before we start creating instances
2951 #ifdef ASSERT
2952 klassOop tmp_k = SystemDictionary::find(vmSymbolHandles::java_lang_String(), Handle(), Handle(), CHECK_0);
2953 assert(tmp_k == NULL, "java/lang/String should not be loaded yet");
2954 #endif
2955 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_String(), Handle(), Handle(), CHECK_0);
2956 KlassHandle k = KlassHandle(THREAD, k_o);
2957 guarantee(k.not_null(), "Must find java/lang/String");
2958 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
2959 ik->initialize(CHECK_0);
2960 fieldDescriptor fd;
2961 // Possible we might not find this field; if so, don't break
2962 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
2963 k()->bool_field_put(fd.offset(), true);
2964 }
2965 }
2966 }
2968 // Initialize java_lang.System (needed before creating the thread)
2969 if (InitializeJavaLangSystem) {
2970 initialize_class(vmSymbolHandles::java_lang_System(), CHECK_0);
2971 initialize_class(vmSymbolHandles::java_lang_ThreadGroup(), CHECK_0);
2972 Handle thread_group = create_initial_thread_group(CHECK_0);
2973 Universe::set_main_thread_group(thread_group());
2974 initialize_class(vmSymbolHandles::java_lang_Thread(), CHECK_0);
2975 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
2976 main_thread->set_threadObj(thread_object);
2977 // Set thread status to running since main thread has
2978 // been started and running.
2979 java_lang_Thread::set_thread_status(thread_object,
2980 java_lang_Thread::RUNNABLE);
2982 // The VM preresolve methods to these classes. Make sure that get initialized
2983 initialize_class(vmSymbolHandles::java_lang_reflect_Method(), CHECK_0);
2984 initialize_class(vmSymbolHandles::java_lang_ref_Finalizer(), CHECK_0);
2985 // The VM creates & returns objects of this class. Make sure it's initialized.
2986 initialize_class(vmSymbolHandles::java_lang_Class(), CHECK_0);
2987 call_initializeSystemClass(CHECK_0);
2988 } else {
2989 warning("java.lang.System not initialized");
2990 }
2992 // an instance of OutOfMemory exception has been allocated earlier
2993 if (InitializeJavaLangExceptionsErrors) {
2994 initialize_class(vmSymbolHandles::java_lang_OutOfMemoryError(), CHECK_0);
2995 initialize_class(vmSymbolHandles::java_lang_NullPointerException(), CHECK_0);
2996 initialize_class(vmSymbolHandles::java_lang_ClassCastException(), CHECK_0);
2997 initialize_class(vmSymbolHandles::java_lang_ArrayStoreException(), CHECK_0);
2998 initialize_class(vmSymbolHandles::java_lang_ArithmeticException(), CHECK_0);
2999 initialize_class(vmSymbolHandles::java_lang_StackOverflowError(), CHECK_0);
3000 initialize_class(vmSymbolHandles::java_lang_IllegalMonitorStateException(), CHECK_0);
3001 } else {
3002 warning("java.lang.OutOfMemoryError has not been initialized");
3003 warning("java.lang.NullPointerException has not been initialized");
3004 warning("java.lang.ClassCastException has not been initialized");
3005 warning("java.lang.ArrayStoreException has not been initialized");
3006 warning("java.lang.ArithmeticException has not been initialized");
3007 warning("java.lang.StackOverflowError has not been initialized");
3008 }
3009 }
3011 // See : bugid 4211085.
3012 // Background : the static initializer of java.lang.Compiler tries to read
3013 // property"java.compiler" and read & write property "java.vm.info".
3014 // When a security manager is installed through the command line
3015 // option "-Djava.security.manager", the above properties are not
3016 // readable and the static initializer for java.lang.Compiler fails
3017 // resulting in a NoClassDefFoundError. This can happen in any
3018 // user code which calls methods in java.lang.Compiler.
3019 // Hack : the hack is to pre-load and initialize this class, so that only
3020 // system domains are on the stack when the properties are read.
3021 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3022 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3023 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3024 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3025 // Once that is done, we should remove this hack.
3026 initialize_class(vmSymbolHandles::java_lang_Compiler(), CHECK_0);
3028 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3029 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3030 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3031 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3032 // This should also be taken out as soon as 4211383 gets fixed.
3033 reset_vm_info_property(CHECK_0);
3035 quicken_jni_functions();
3037 // Set flag that basic initialization has completed. Used by exceptions and various
3038 // debug stuff, that does not work until all basic classes have been initialized.
3039 set_init_completed();
3041 HS_DTRACE_PROBE(hotspot, vm__init__end);
3043 // record VM initialization completion time
3044 Management::record_vm_init_completed();
3046 // Compute system loader. Note that this has to occur after set_init_completed, since
3047 // valid exceptions may be thrown in the process.
3048 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3049 // set_init_completed has just been called, causing exceptions not to be shortcut
3050 // anymore. We call vm_exit_during_initialization directly instead.
3051 SystemDictionary::compute_java_system_loader(THREAD);
3052 if (HAS_PENDING_EXCEPTION) {
3053 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3054 }
3056 #ifndef SERIALGC
3057 // Support for ConcurrentMarkSweep. This should be cleaned up
3058 // and better encapsulated. XXX YSR
3059 if (UseConcMarkSweepGC) {
3060 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3061 if (HAS_PENDING_EXCEPTION) {
3062 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3063 }
3064 }
3065 #endif // SERIALGC
3067 // Always call even when there are not JVMTI environments yet, since environments
3068 // may be attached late and JVMTI must track phases of VM execution
3069 JvmtiExport::enter_live_phase();
3071 // Signal Dispatcher needs to be started before VMInit event is posted
3072 os::signal_init();
3074 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3075 if (!DisableAttachMechanism) {
3076 if (StartAttachListener || AttachListener::init_at_startup()) {
3077 AttachListener::init();
3078 }
3079 }
3081 // Launch -Xrun agents
3082 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3083 // back-end can launch with -Xdebug -Xrunjdwp.
3084 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3085 create_vm_init_libraries();
3086 }
3088 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3089 JvmtiExport::post_vm_initialized();
3091 Chunk::start_chunk_pool_cleaner_task();
3093 // initialize compiler(s)
3094 CompileBroker::compilation_init();
3096 Management::initialize(THREAD);
3097 if (HAS_PENDING_EXCEPTION) {
3098 // management agent fails to start possibly due to
3099 // configuration problem and is responsible for printing
3100 // stack trace if appropriate. Simply exit VM.
3101 vm_exit(1);
3102 }
3104 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3105 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3106 if (MemProfiling) MemProfiler::engage();
3107 StatSampler::engage();
3108 if (CheckJNICalls) JniPeriodicChecker::engage();
3110 BiasedLocking::init();
3113 // Start up the WatcherThread if there are any periodic tasks
3114 // NOTE: All PeriodicTasks should be registered by now. If they
3115 // aren't, late joiners might appear to start slowly (we might
3116 // take a while to process their first tick).
3117 if (PeriodicTask::num_tasks() > 0) {
3118 WatcherThread::start();
3119 }
3121 create_vm_timer.end();
3122 return JNI_OK;
3123 }
3125 // type for the Agent_OnLoad and JVM_OnLoad entry points
3126 extern "C" {
3127 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3128 }
3129 // Find a command line agent library and return its entry point for
3130 // -agentlib: -agentpath: -Xrun
3131 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3132 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3133 OnLoadEntry_t on_load_entry = NULL;
3134 void *library = agent->os_lib(); // check if we have looked it up before
3136 if (library == NULL) {
3137 char buffer[JVM_MAXPATHLEN];
3138 char ebuf[1024];
3139 const char *name = agent->name();
3141 if (agent->is_absolute_path()) {
3142 library = hpi::dll_load(name, ebuf, sizeof ebuf);
3143 if (library == NULL) {
3144 // If we can't find the agent, exit.
3145 vm_exit_during_initialization("Could not find agent library in absolute path", name);
3146 }
3147 } else {
3148 // Try to load the agent from the standard dll directory
3149 hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
3150 library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3151 #ifdef KERNEL
3152 // Download instrument dll
3153 if (library == NULL && strcmp(name, "instrument") == 0) {
3154 char *props = Arguments::get_kernel_properties();
3155 char *home = Arguments::get_java_home();
3156 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false"
3157 " sun.jkernel.DownloadManager -download client_jvm";
3158 int length = strlen(props) + strlen(home) + strlen(fmt) + 1;
3159 char *cmd = AllocateHeap(length);
3160 jio_snprintf(cmd, length, fmt, home, props);
3161 int status = os::fork_and_exec(cmd);
3162 FreeHeap(props);
3163 FreeHeap(cmd);
3164 if (status == -1) {
3165 warning(cmd);
3166 vm_exit_during_initialization("fork_and_exec failed: %s",
3167 strerror(errno));
3168 }
3169 // when this comes back the instrument.dll should be where it belongs.
3170 library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3171 }
3172 #endif // KERNEL
3173 if (library == NULL) { // Try the local directory
3174 char ns[1] = {0};
3175 hpi::dll_build_name(buffer, sizeof(buffer), ns, name);
3176 library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3177 if (library == NULL) {
3178 // If we can't find the agent, exit.
3179 vm_exit_during_initialization("Could not find agent library on the library path or in the local directory", name);
3180 }
3181 }
3182 }
3183 agent->set_os_lib(library);
3184 }
3186 // Find the OnLoad function.
3187 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3188 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, hpi::dll_lookup(library, on_load_symbols[symbol_index]));
3189 if (on_load_entry != NULL) break;
3190 }
3191 return on_load_entry;
3192 }
3194 // Find the JVM_OnLoad entry point
3195 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3196 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3197 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3198 }
3200 // Find the Agent_OnLoad entry point
3201 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3202 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3203 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3204 }
3206 // For backwards compatibility with -Xrun
3207 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3208 // treated like -agentpath:
3209 // Must be called before agent libraries are created
3210 void Threads::convert_vm_init_libraries_to_agents() {
3211 AgentLibrary* agent;
3212 AgentLibrary* next;
3214 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3215 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3216 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3218 // If there is an JVM_OnLoad function it will get called later,
3219 // otherwise see if there is an Agent_OnLoad
3220 if (on_load_entry == NULL) {
3221 on_load_entry = lookup_agent_on_load(agent);
3222 if (on_load_entry != NULL) {
3223 // switch it to the agent list -- so that Agent_OnLoad will be called,
3224 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3225 Arguments::convert_library_to_agent(agent);
3226 } else {
3227 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3228 }
3229 }
3230 }
3231 }
3233 // Create agents for -agentlib: -agentpath: and converted -Xrun
3234 // Invokes Agent_OnLoad
3235 // Called very early -- before JavaThreads exist
3236 void Threads::create_vm_init_agents() {
3237 extern struct JavaVM_ main_vm;
3238 AgentLibrary* agent;
3240 JvmtiExport::enter_onload_phase();
3241 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3242 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3244 if (on_load_entry != NULL) {
3245 // Invoke the Agent_OnLoad function
3246 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3247 if (err != JNI_OK) {
3248 vm_exit_during_initialization("agent library failed to init", agent->name());
3249 }
3250 } else {
3251 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3252 }
3253 }
3254 JvmtiExport::enter_primordial_phase();
3255 }
3257 extern "C" {
3258 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3259 }
3261 void Threads::shutdown_vm_agents() {
3262 // Send any Agent_OnUnload notifications
3263 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3264 extern struct JavaVM_ main_vm;
3265 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3267 // Find the Agent_OnUnload function.
3268 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3269 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3270 hpi::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3272 // Invoke the Agent_OnUnload function
3273 if (unload_entry != NULL) {
3274 JavaThread* thread = JavaThread::current();
3275 ThreadToNativeFromVM ttn(thread);
3276 HandleMark hm(thread);
3277 (*unload_entry)(&main_vm);
3278 break;
3279 }
3280 }
3281 }
3282 }
3284 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3285 // Invokes JVM_OnLoad
3286 void Threads::create_vm_init_libraries() {
3287 extern struct JavaVM_ main_vm;
3288 AgentLibrary* agent;
3290 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3291 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3293 if (on_load_entry != NULL) {
3294 // Invoke the JVM_OnLoad function
3295 JavaThread* thread = JavaThread::current();
3296 ThreadToNativeFromVM ttn(thread);
3297 HandleMark hm(thread);
3298 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3299 if (err != JNI_OK) {
3300 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3301 }
3302 } else {
3303 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3304 }
3305 }
3306 }
3308 // Last thread running calls java.lang.Shutdown.shutdown()
3309 void JavaThread::invoke_shutdown_hooks() {
3310 HandleMark hm(this);
3312 // We could get here with a pending exception, if so clear it now.
3313 if (this->has_pending_exception()) {
3314 this->clear_pending_exception();
3315 }
3317 EXCEPTION_MARK;
3318 klassOop k =
3319 SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_Shutdown(),
3320 THREAD);
3321 if (k != NULL) {
3322 // SystemDictionary::resolve_or_null will return null if there was
3323 // an exception. If we cannot load the Shutdown class, just don't
3324 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3325 // and finalizers (if runFinalizersOnExit is set) won't be run.
3326 // Note that if a shutdown hook was registered or runFinalizersOnExit
3327 // was called, the Shutdown class would have already been loaded
3328 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3329 instanceKlassHandle shutdown_klass (THREAD, k);
3330 JavaValue result(T_VOID);
3331 JavaCalls::call_static(&result,
3332 shutdown_klass,
3333 vmSymbolHandles::shutdown_method_name(),
3334 vmSymbolHandles::void_method_signature(),
3335 THREAD);
3336 }
3337 CLEAR_PENDING_EXCEPTION;
3338 }
3340 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3341 // the program falls off the end of main(). Another VM exit path is through
3342 // vm_exit() when the program calls System.exit() to return a value or when
3343 // there is a serious error in VM. The two shutdown paths are not exactly
3344 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3345 // and VM_Exit op at VM level.
3346 //
3347 // Shutdown sequence:
3348 // + Wait until we are the last non-daemon thread to execute
3349 // <-- every thing is still working at this moment -->
3350 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3351 // shutdown hooks, run finalizers if finalization-on-exit
3352 // + Call before_exit(), prepare for VM exit
3353 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3354 // currently the only user of this mechanism is File.deleteOnExit())
3355 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3356 // post thread end and vm death events to JVMTI,
3357 // stop signal thread
3358 // + Call JavaThread::exit(), it will:
3359 // > release JNI handle blocks, remove stack guard pages
3360 // > remove this thread from Threads list
3361 // <-- no more Java code from this thread after this point -->
3362 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3363 // the compiler threads at safepoint
3364 // <-- do not use anything that could get blocked by Safepoint -->
3365 // + Disable tracing at JNI/JVM barriers
3366 // + Set _vm_exited flag for threads that are still running native code
3367 // + Delete this thread
3368 // + Call exit_globals()
3369 // > deletes tty
3370 // > deletes PerfMemory resources
3371 // + Return to caller
3373 bool Threads::destroy_vm() {
3374 JavaThread* thread = JavaThread::current();
3376 // Wait until we are the last non-daemon thread to execute
3377 { MutexLocker nu(Threads_lock);
3378 while (Threads::number_of_non_daemon_threads() > 1 )
3379 // This wait should make safepoint checks, wait without a timeout,
3380 // and wait as a suspend-equivalent condition.
3381 //
3382 // Note: If the FlatProfiler is running and this thread is waiting
3383 // for another non-daemon thread to finish, then the FlatProfiler
3384 // is waiting for the external suspend request on this thread to
3385 // complete. wait_for_ext_suspend_completion() will eventually
3386 // timeout, but that takes time. Making this wait a suspend-
3387 // equivalent condition solves that timeout problem.
3388 //
3389 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3390 Mutex::_as_suspend_equivalent_flag);
3391 }
3393 // Hang forever on exit if we are reporting an error.
3394 if (ShowMessageBoxOnError && is_error_reported()) {
3395 os::infinite_sleep();
3396 }
3398 if (JDK_Version::is_jdk12x_version()) {
3399 // We are the last thread running, so check if finalizers should be run.
3400 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3401 HandleMark rm(thread);
3402 Universe::run_finalizers_on_exit();
3403 } else {
3404 // run Java level shutdown hooks
3405 thread->invoke_shutdown_hooks();
3406 }
3408 before_exit(thread);
3410 thread->exit(true);
3412 // Stop VM thread.
3413 {
3414 // 4945125 The vm thread comes to a safepoint during exit.
3415 // GC vm_operations can get caught at the safepoint, and the
3416 // heap is unparseable if they are caught. Grab the Heap_lock
3417 // to prevent this. The GC vm_operations will not be able to
3418 // queue until after the vm thread is dead.
3419 MutexLocker ml(Heap_lock);
3421 VMThread::wait_for_vm_thread_exit();
3422 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3423 VMThread::destroy();
3424 }
3426 // clean up ideal graph printers
3427 #if defined(COMPILER2) && !defined(PRODUCT)
3428 IdealGraphPrinter::clean_up();
3429 #endif
3431 // Now, all Java threads are gone except daemon threads. Daemon threads
3432 // running Java code or in VM are stopped by the Safepoint. However,
3433 // daemon threads executing native code are still running. But they
3434 // will be stopped at native=>Java/VM barriers. Note that we can't
3435 // simply kill or suspend them, as it is inherently deadlock-prone.
3437 #ifndef PRODUCT
3438 // disable function tracing at JNI/JVM barriers
3439 TraceHPI = false;
3440 TraceJNICalls = false;
3441 TraceJVMCalls = false;
3442 TraceRuntimeCalls = false;
3443 #endif
3445 VM_Exit::set_vm_exited();
3447 notify_vm_shutdown();
3449 delete thread;
3451 // exit_globals() will delete tty
3452 exit_globals();
3454 return true;
3455 }
3458 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3459 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3460 return is_supported_jni_version(version);
3461 }
3464 jboolean Threads::is_supported_jni_version(jint version) {
3465 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3466 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3467 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3468 return JNI_FALSE;
3469 }
3472 void Threads::add(JavaThread* p, bool force_daemon) {
3473 // The threads lock must be owned at this point
3474 assert_locked_or_safepoint(Threads_lock);
3475 p->set_next(_thread_list);
3476 _thread_list = p;
3477 _number_of_threads++;
3478 oop threadObj = p->threadObj();
3479 bool daemon = true;
3480 // Bootstrapping problem: threadObj can be null for initial
3481 // JavaThread (or for threads attached via JNI)
3482 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3483 _number_of_non_daemon_threads++;
3484 daemon = false;
3485 }
3487 ThreadService::add_thread(p, daemon);
3489 // Possible GC point.
3490 Events::log("Thread added: " INTPTR_FORMAT, p);
3491 }
3493 void Threads::remove(JavaThread* p) {
3494 // Extra scope needed for Thread_lock, so we can check
3495 // that we do not remove thread without safepoint code notice
3496 { MutexLocker ml(Threads_lock);
3498 assert(includes(p), "p must be present");
3500 JavaThread* current = _thread_list;
3501 JavaThread* prev = NULL;
3503 while (current != p) {
3504 prev = current;
3505 current = current->next();
3506 }
3508 if (prev) {
3509 prev->set_next(current->next());
3510 } else {
3511 _thread_list = p->next();
3512 }
3513 _number_of_threads--;
3514 oop threadObj = p->threadObj();
3515 bool daemon = true;
3516 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
3517 _number_of_non_daemon_threads--;
3518 daemon = false;
3520 // Only one thread left, do a notify on the Threads_lock so a thread waiting
3521 // on destroy_vm will wake up.
3522 if (number_of_non_daemon_threads() == 1)
3523 Threads_lock->notify_all();
3524 }
3525 ThreadService::remove_thread(p, daemon);
3527 // Make sure that safepoint code disregard this thread. This is needed since
3528 // the thread might mess around with locks after this point. This can cause it
3529 // to do callbacks into the safepoint code. However, the safepoint code is not aware
3530 // of this thread since it is removed from the queue.
3531 p->set_terminated_value();
3532 } // unlock Threads_lock
3534 // Since Events::log uses a lock, we grab it outside the Threads_lock
3535 Events::log("Thread exited: " INTPTR_FORMAT, p);
3536 }
3538 // Threads_lock must be held when this is called (or must be called during a safepoint)
3539 bool Threads::includes(JavaThread* p) {
3540 assert(Threads_lock->is_locked(), "sanity check");
3541 ALL_JAVA_THREADS(q) {
3542 if (q == p ) {
3543 return true;
3544 }
3545 }
3546 return false;
3547 }
3549 // Operations on the Threads list for GC. These are not explicitly locked,
3550 // but the garbage collector must provide a safe context for them to run.
3551 // In particular, these things should never be called when the Threads_lock
3552 // is held by some other thread. (Note: the Safepoint abstraction also
3553 // uses the Threads_lock to gurantee this property. It also makes sure that
3554 // all threads gets blocked when exiting or starting).
3556 void Threads::oops_do(OopClosure* f) {
3557 ALL_JAVA_THREADS(p) {
3558 p->oops_do(f);
3559 }
3560 VMThread::vm_thread()->oops_do(f);
3561 }
3563 void Threads::possibly_parallel_oops_do(OopClosure* f) {
3564 // Introduce a mechanism allowing parallel threads to claim threads as
3565 // root groups. Overhead should be small enough to use all the time,
3566 // even in sequential code.
3567 SharedHeap* sh = SharedHeap::heap();
3568 bool is_par = (sh->n_par_threads() > 0);
3569 int cp = SharedHeap::heap()->strong_roots_parity();
3570 ALL_JAVA_THREADS(p) {
3571 if (p->claim_oops_do(is_par, cp)) {
3572 p->oops_do(f);
3573 }
3574 }
3575 VMThread* vmt = VMThread::vm_thread();
3576 if (vmt->claim_oops_do(is_par, cp))
3577 vmt->oops_do(f);
3578 }
3580 #ifndef SERIALGC
3581 // Used by ParallelScavenge
3582 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
3583 ALL_JAVA_THREADS(p) {
3584 q->enqueue(new ThreadRootsTask(p));
3585 }
3586 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
3587 }
3589 // Used by Parallel Old
3590 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
3591 ALL_JAVA_THREADS(p) {
3592 q->enqueue(new ThreadRootsMarkingTask(p));
3593 }
3594 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
3595 }
3596 #endif // SERIALGC
3598 void Threads::nmethods_do() {
3599 ALL_JAVA_THREADS(p) {
3600 p->nmethods_do();
3601 }
3602 VMThread::vm_thread()->nmethods_do();
3603 }
3605 void Threads::gc_epilogue() {
3606 ALL_JAVA_THREADS(p) {
3607 p->gc_epilogue();
3608 }
3609 }
3611 void Threads::gc_prologue() {
3612 ALL_JAVA_THREADS(p) {
3613 p->gc_prologue();
3614 }
3615 }
3617 void Threads::deoptimized_wrt_marked_nmethods() {
3618 ALL_JAVA_THREADS(p) {
3619 p->deoptimized_wrt_marked_nmethods();
3620 }
3621 }
3624 // Get count Java threads that are waiting to enter the specified monitor.
3625 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
3626 address monitor, bool doLock) {
3627 assert(doLock || SafepointSynchronize::is_at_safepoint(),
3628 "must grab Threads_lock or be at safepoint");
3629 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3631 int i = 0;
3632 {
3633 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3634 ALL_JAVA_THREADS(p) {
3635 if (p->is_Compiler_thread()) continue;
3637 address pending = (address)p->current_pending_monitor();
3638 if (pending == monitor) { // found a match
3639 if (i < count) result->append(p); // save the first count matches
3640 i++;
3641 }
3642 }
3643 }
3644 return result;
3645 }
3648 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
3649 assert(doLock ||
3650 Threads_lock->owned_by_self() ||
3651 SafepointSynchronize::is_at_safepoint(),
3652 "must grab Threads_lock or be at safepoint");
3654 // NULL owner means not locked so we can skip the search
3655 if (owner == NULL) return NULL;
3657 {
3658 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3659 ALL_JAVA_THREADS(p) {
3660 // first, see if owner is the address of a Java thread
3661 if (owner == (address)p) return p;
3662 }
3663 }
3664 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
3665 if (UseHeavyMonitors) return NULL;
3667 //
3668 // If we didn't find a matching Java thread and we didn't force use of
3669 // heavyweight monitors, then the owner is the stack address of the
3670 // Lock Word in the owning Java thread's stack.
3671 //
3672 // We can't use Thread::is_lock_owned() or Thread::lock_is_in_stack() because
3673 // those routines rely on the "current" stack pointer. That would be our
3674 // stack pointer which is not relevant to the question. Instead we use the
3675 // highest lock ever entered by the thread and find the thread that is
3676 // higher than and closest to our target stack address.
3677 //
3678 address least_diff = 0;
3679 bool least_diff_initialized = false;
3680 JavaThread* the_owner = NULL;
3681 {
3682 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3683 ALL_JAVA_THREADS(q) {
3684 address addr = q->highest_lock();
3685 if (addr == NULL || addr < owner) continue; // thread has entered no monitors or is too low
3686 address diff = (address)(addr - owner);
3687 if (!least_diff_initialized || diff < least_diff) {
3688 least_diff_initialized = true;
3689 least_diff = diff;
3690 the_owner = q;
3691 }
3692 }
3693 }
3694 assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
3695 return the_owner;
3696 }
3698 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
3699 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
3700 char buf[32];
3701 st->print_cr(os::local_time_string(buf, sizeof(buf)));
3703 st->print_cr("Full thread dump %s (%s %s):",
3704 Abstract_VM_Version::vm_name(),
3705 Abstract_VM_Version::vm_release(),
3706 Abstract_VM_Version::vm_info_string()
3707 );
3708 st->cr();
3710 #ifndef SERIALGC
3711 // Dump concurrent locks
3712 ConcurrentLocksDump concurrent_locks;
3713 if (print_concurrent_locks) {
3714 concurrent_locks.dump_at_safepoint();
3715 }
3716 #endif // SERIALGC
3718 ALL_JAVA_THREADS(p) {
3719 ResourceMark rm;
3720 p->print_on(st);
3721 if (print_stacks) {
3722 if (internal_format) {
3723 p->trace_stack();
3724 } else {
3725 p->print_stack_on(st);
3726 }
3727 }
3728 st->cr();
3729 #ifndef SERIALGC
3730 if (print_concurrent_locks) {
3731 concurrent_locks.print_locks_on(p, st);
3732 }
3733 #endif // SERIALGC
3734 }
3736 VMThread::vm_thread()->print_on(st);
3737 st->cr();
3738 Universe::heap()->print_gc_threads_on(st);
3739 WatcherThread* wt = WatcherThread::watcher_thread();
3740 if (wt != NULL) wt->print_on(st);
3741 st->cr();
3742 CompileBroker::print_compiler_threads_on(st);
3743 st->flush();
3744 }
3746 // Threads::print_on_error() is called by fatal error handler. It's possible
3747 // that VM is not at safepoint and/or current thread is inside signal handler.
3748 // Don't print stack trace, as the stack may not be walkable. Don't allocate
3749 // memory (even in resource area), it might deadlock the error handler.
3750 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
3751 bool found_current = false;
3752 st->print_cr("Java Threads: ( => current thread )");
3753 ALL_JAVA_THREADS(thread) {
3754 bool is_current = (current == thread);
3755 found_current = found_current || is_current;
3757 st->print("%s", is_current ? "=>" : " ");
3759 st->print(PTR_FORMAT, thread);
3760 st->print(" ");
3761 thread->print_on_error(st, buf, buflen);
3762 st->cr();
3763 }
3764 st->cr();
3766 st->print_cr("Other Threads:");
3767 if (VMThread::vm_thread()) {
3768 bool is_current = (current == VMThread::vm_thread());
3769 found_current = found_current || is_current;
3770 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
3772 st->print(PTR_FORMAT, VMThread::vm_thread());
3773 st->print(" ");
3774 VMThread::vm_thread()->print_on_error(st, buf, buflen);
3775 st->cr();
3776 }
3777 WatcherThread* wt = WatcherThread::watcher_thread();
3778 if (wt != NULL) {
3779 bool is_current = (current == wt);
3780 found_current = found_current || is_current;
3781 st->print("%s", is_current ? "=>" : " ");
3783 st->print(PTR_FORMAT, wt);
3784 st->print(" ");
3785 wt->print_on_error(st, buf, buflen);
3786 st->cr();
3787 }
3788 if (!found_current) {
3789 st->cr();
3790 st->print("=>" PTR_FORMAT " (exited) ", current);
3791 current->print_on_error(st, buf, buflen);
3792 st->cr();
3793 }
3794 }
3797 // Lifecycle management for TSM ParkEvents.
3798 // ParkEvents are type-stable (TSM).
3799 // In our particular implementation they happen to be immortal.
3800 //
3801 // We manage concurrency on the FreeList with a CAS-based
3802 // detach-modify-reattach idiom that avoids the ABA problems
3803 // that would otherwise be present in a simple CAS-based
3804 // push-pop implementation. (push-one and pop-all)
3805 //
3806 // Caveat: Allocate() and Release() may be called from threads
3807 // other than the thread associated with the Event!
3808 // If we need to call Allocate() when running as the thread in
3809 // question then look for the PD calls to initialize native TLS.
3810 // Native TLS (Win32/Linux/Solaris) can only be initialized or
3811 // accessed by the associated thread.
3812 // See also pd_initialize().
3813 //
3814 // Note that we could defer associating a ParkEvent with a thread
3815 // until the 1st time the thread calls park(). unpark() calls to
3816 // an unprovisioned thread would be ignored. The first park() call
3817 // for a thread would allocate and associate a ParkEvent and return
3818 // immediately.
3820 volatile int ParkEvent::ListLock = 0 ;
3821 ParkEvent * volatile ParkEvent::FreeList = NULL ;
3823 ParkEvent * ParkEvent::Allocate (Thread * t) {
3824 // In rare cases -- JVM_RawMonitor* operations -- we can find t == null.
3825 ParkEvent * ev ;
3827 // Start by trying to recycle an existing but unassociated
3828 // ParkEvent from the global free list.
3829 for (;;) {
3830 ev = FreeList ;
3831 if (ev == NULL) break ;
3832 // 1: Detach - sequester or privatize the list
3833 // Tantamount to ev = Swap (&FreeList, NULL)
3834 if (Atomic::cmpxchg_ptr (NULL, &FreeList, ev) != ev) {
3835 continue ;
3836 }
3838 // We've detached the list. The list in-hand is now
3839 // local to this thread. This thread can operate on the
3840 // list without risk of interference from other threads.
3841 // 2: Extract -- pop the 1st element from the list.
3842 ParkEvent * List = ev->FreeNext ;
3843 if (List == NULL) break ;
3844 for (;;) {
3845 // 3: Try to reattach the residual list
3846 guarantee (List != NULL, "invariant") ;
3847 ParkEvent * Arv = (ParkEvent *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ;
3848 if (Arv == NULL) break ;
3850 // New nodes arrived. Try to detach the recent arrivals.
3851 if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) {
3852 continue ;
3853 }
3854 guarantee (Arv != NULL, "invariant") ;
3855 // 4: Merge Arv into List
3856 ParkEvent * Tail = List ;
3857 while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ;
3858 Tail->FreeNext = Arv ;
3859 }
3860 break ;
3861 }
3863 if (ev != NULL) {
3864 guarantee (ev->AssociatedWith == NULL, "invariant") ;
3865 } else {
3866 // Do this the hard way -- materialize a new ParkEvent.
3867 // In rare cases an allocating thread might detach a long list --
3868 // installing null into FreeList -- and then stall or be obstructed.
3869 // A 2nd thread calling Allocate() would see FreeList == null.
3870 // The list held privately by the 1st thread is unavailable to the 2nd thread.
3871 // In that case the 2nd thread would have to materialize a new ParkEvent,
3872 // even though free ParkEvents existed in the system. In this case we end up
3873 // with more ParkEvents in circulation than we need, but the race is
3874 // rare and the outcome is benign. Ideally, the # of extant ParkEvents
3875 // is equal to the maximum # of threads that existed at any one time.
3876 // Because of the race mentioned above, segments of the freelist
3877 // can be transiently inaccessible. At worst we may end up with the
3878 // # of ParkEvents in circulation slightly above the ideal.
3879 // Note that if we didn't have the TSM/immortal constraint, then
3880 // when reattaching, above, we could trim the list.
3881 ev = new ParkEvent () ;
3882 guarantee ((intptr_t(ev) & 0xFF) == 0, "invariant") ;
3883 }
3884 ev->reset() ; // courtesy to caller
3885 ev->AssociatedWith = t ; // Associate ev with t
3886 ev->FreeNext = NULL ;
3887 return ev ;
3888 }
3890 void ParkEvent::Release (ParkEvent * ev) {
3891 if (ev == NULL) return ;
3892 guarantee (ev->FreeNext == NULL , "invariant") ;
3893 ev->AssociatedWith = NULL ;
3894 for (;;) {
3895 // Push ev onto FreeList
3896 // The mechanism is "half" lock-free.
3897 ParkEvent * List = FreeList ;
3898 ev->FreeNext = List ;
3899 if (Atomic::cmpxchg_ptr (ev, &FreeList, List) == List) break ;
3900 }
3901 }
3903 // Override operator new and delete so we can ensure that the
3904 // least significant byte of ParkEvent addresses is 0.
3905 // Beware that excessive address alignment is undesirable
3906 // as it can result in D$ index usage imbalance as
3907 // well as bank access imbalance on Niagara-like platforms,
3908 // although Niagara's hash function should help.
3910 void * ParkEvent::operator new (size_t sz) {
3911 return (void *) ((intptr_t (CHeapObj::operator new (sz + 256)) + 256) & -256) ;
3912 }
3914 void ParkEvent::operator delete (void * a) {
3915 // ParkEvents are type-stable and immortal ...
3916 ShouldNotReachHere();
3917 }
3920 // 6399321 As a temporary measure we copied & modified the ParkEvent::
3921 // allocate() and release() code for use by Parkers. The Parker:: forms
3922 // will eventually be removed as we consolide and shift over to ParkEvents
3923 // for both builtin synchronization and JSR166 operations.
3925 volatile int Parker::ListLock = 0 ;
3926 Parker * volatile Parker::FreeList = NULL ;
3928 Parker * Parker::Allocate (JavaThread * t) {
3929 guarantee (t != NULL, "invariant") ;
3930 Parker * p ;
3932 // Start by trying to recycle an existing but unassociated
3933 // Parker from the global free list.
3934 for (;;) {
3935 p = FreeList ;
3936 if (p == NULL) break ;
3937 // 1: Detach
3938 // Tantamount to p = Swap (&FreeList, NULL)
3939 if (Atomic::cmpxchg_ptr (NULL, &FreeList, p) != p) {
3940 continue ;
3941 }
3943 // We've detached the list. The list in-hand is now
3944 // local to this thread. This thread can operate on the
3945 // list without risk of interference from other threads.
3946 // 2: Extract -- pop the 1st element from the list.
3947 Parker * List = p->FreeNext ;
3948 if (List == NULL) break ;
3949 for (;;) {
3950 // 3: Try to reattach the residual list
3951 guarantee (List != NULL, "invariant") ;
3952 Parker * Arv = (Parker *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ;
3953 if (Arv == NULL) break ;
3955 // New nodes arrived. Try to detach the recent arrivals.
3956 if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) {
3957 continue ;
3958 }
3959 guarantee (Arv != NULL, "invariant") ;
3960 // 4: Merge Arv into List
3961 Parker * Tail = List ;
3962 while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ;
3963 Tail->FreeNext = Arv ;
3964 }
3965 break ;
3966 }
3968 if (p != NULL) {
3969 guarantee (p->AssociatedWith == NULL, "invariant") ;
3970 } else {
3971 // Do this the hard way -- materialize a new Parker..
3972 // In rare cases an allocating thread might detach
3973 // a long list -- installing null into FreeList --and
3974 // then stall. Another thread calling Allocate() would see
3975 // FreeList == null and then invoke the ctor. In this case we
3976 // end up with more Parkers in circulation than we need, but
3977 // the race is rare and the outcome is benign.
3978 // Ideally, the # of extant Parkers is equal to the
3979 // maximum # of threads that existed at any one time.
3980 // Because of the race mentioned above, segments of the
3981 // freelist can be transiently inaccessible. At worst
3982 // we may end up with the # of Parkers in circulation
3983 // slightly above the ideal.
3984 p = new Parker() ;
3985 }
3986 p->AssociatedWith = t ; // Associate p with t
3987 p->FreeNext = NULL ;
3988 return p ;
3989 }
3992 void Parker::Release (Parker * p) {
3993 if (p == NULL) return ;
3994 guarantee (p->AssociatedWith != NULL, "invariant") ;
3995 guarantee (p->FreeNext == NULL , "invariant") ;
3996 p->AssociatedWith = NULL ;
3997 for (;;) {
3998 // Push p onto FreeList
3999 Parker * List = FreeList ;
4000 p->FreeNext = List ;
4001 if (Atomic::cmpxchg_ptr (p, &FreeList, List) == List) break ;
4002 }
4003 }
4005 void Threads::verify() {
4006 ALL_JAVA_THREADS(p) {
4007 p->verify();
4008 }
4009 VMThread* thread = VMThread::vm_thread();
4010 if (thread != NULL) thread->verify();
4011 }