1 /*
2 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "jvmtifiles/jvmtiEnv.hpp"
36 #include "memory/oopFactory.hpp"
37 #include "memory/universe.inline.hpp"
38 #include "oops/instanceKlass.hpp"
39 #include "oops/objArrayOop.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "oops/symbol.hpp"
42 #include "prims/jvm_misc.hpp"
43 #include "prims/jvmtiExport.hpp"
44 #include "prims/jvmtiThreadState.hpp"
45 #include "prims/privilegedStack.hpp"
46 #include "runtime/aprofiler.hpp"
47 #include "runtime/arguments.hpp"
48 #include "runtime/biasedLocking.hpp"
49 #include "runtime/deoptimization.hpp"
50 #include "runtime/fprofiler.hpp"
51 #include "runtime/frame.inline.hpp"
52 #include "runtime/init.hpp"
53 #include "runtime/interfaceSupport.hpp"
54 #include "runtime/java.hpp"
55 #include "runtime/javaCalls.hpp"
56 #include "runtime/jniPeriodicChecker.hpp"
57 #include "runtime/memprofiler.hpp"
58 #include "runtime/mutexLocker.hpp"
59 #include "runtime/objectMonitor.hpp"
60 #include "runtime/osThread.hpp"
61 #include "runtime/safepoint.hpp"
62 #include "runtime/sharedRuntime.hpp"
63 #include "runtime/statSampler.hpp"
64 #include "runtime/stubRoutines.hpp"
65 #include "runtime/task.hpp"
66 #include "runtime/threadCritical.hpp"
67 #include "runtime/threadLocalStorage.hpp"
68 #include "runtime/vframe.hpp"
69 #include "runtime/vframeArray.hpp"
70 #include "runtime/vframe_hp.hpp"
71 #include "runtime/vmThread.hpp"
72 #include "runtime/vm_operations.hpp"
73 #include "services/attachListener.hpp"
74 #include "services/management.hpp"
75 #include "services/threadService.hpp"
76 #include "utilities/defaultStream.hpp"
77 #include "utilities/dtrace.hpp"
78 #include "utilities/events.hpp"
79 #include "utilities/preserveException.hpp"
80 #ifdef TARGET_OS_FAMILY_linux
81 # include "os_linux.inline.hpp"
82 # include "thread_linux.inline.hpp"
83 #endif
84 #ifdef TARGET_OS_FAMILY_solaris
85 # include "os_solaris.inline.hpp"
86 # include "thread_solaris.inline.hpp"
87 #endif
88 #ifdef TARGET_OS_FAMILY_windows
89 # include "os_windows.inline.hpp"
90 # include "thread_windows.inline.hpp"
91 #endif
92 #ifndef SERIALGC
93 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
94 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
95 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
96 #endif
97 #ifdef COMPILER1
98 #include "c1/c1_Compiler.hpp"
99 #endif
100 #ifdef COMPILER2
101 #include "opto/c2compiler.hpp"
102 #include "opto/idealGraphPrinter.hpp"
103 #endif
104
105 #ifdef DTRACE_ENABLED
106
107 // Only bother with this argument setup if dtrace is available
108
109 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
110 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
111 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
112 intptr_t, intptr_t, bool);
113 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
114 intptr_t, intptr_t, bool);
115
116 #define DTRACE_THREAD_PROBE(probe, javathread) \
117 { \
118 ResourceMark rm(this); \
119 int len = 0; \
120 const char* name = (javathread)->get_thread_name(); \
121 len = strlen(name); \
122 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
123 name, len, \
124 java_lang_Thread::thread_id((javathread)->threadObj()), \
125 (javathread)->osthread()->thread_id(), \
126 java_lang_Thread::is_daemon((javathread)->threadObj())); \
127 }
128
129 #else // ndef DTRACE_ENABLED
130
131 #define DTRACE_THREAD_PROBE(probe, javathread)
132
133 #endif // ndef DTRACE_ENABLED
134
135 // Class hierarchy
136 // - Thread
137 // - VMThread
138 // - WatcherThread
139 // - ConcurrentMarkSweepThread
140 // - JavaThread
141 // - CompilerThread
142
143 // ======= Thread ========
144
145 // Support for forcing alignment of thread objects for biased locking
146 void* Thread::operator new(size_t size) {
147 if (UseBiasedLocking) {
148 const int alignment = markOopDesc::biased_lock_alignment;
149 size_t aligned_size = size + (alignment - sizeof(intptr_t));
150 void* real_malloc_addr = CHeapObj::operator new(aligned_size);
151 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
152 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
153 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
154 "JavaThread alignment code overflowed allocated storage");
155 if (TraceBiasedLocking) {
156 if (aligned_addr != real_malloc_addr)
157 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
158 real_malloc_addr, aligned_addr);
159 }
160 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
161 return aligned_addr;
162 } else {
163 return CHeapObj::operator new(size);
164 }
165 }
166
167 void Thread::operator delete(void* p) {
168 if (UseBiasedLocking) {
169 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
170 CHeapObj::operator delete(real_malloc_addr);
171 } else {
172 CHeapObj::operator delete(p);
173 }
174 }
175
176
177 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
178 // JavaThread
179
180
181 Thread::Thread() {
182 // stack and get_thread
183 set_stack_base(NULL);
184 set_stack_size(0);
185 set_self_raw_id(0);
186 set_lgrp_id(-1);
187
188 // allocated data structures
189 set_osthread(NULL);
190 set_resource_area(new ResourceArea());
191 set_handle_area(new HandleArea(NULL));
192 set_active_handles(NULL);
193 set_free_handle_block(NULL);
194 set_last_handle_mark(NULL);
195
196 // This initial value ==> never claimed.
197 _oops_do_parity = 0;
198
199 // the handle mark links itself to last_handle_mark
200 new HandleMark(this);
201
202 // plain initialization
203 debug_only(_owned_locks = NULL;)
204 debug_only(_allow_allocation_count = 0;)
205 NOT_PRODUCT(_allow_safepoint_count = 0;)
206 NOT_PRODUCT(_skip_gcalot = false;)
207 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
208 _jvmti_env_iteration_count = 0;
209 set_allocated_bytes(0);
210 _vm_operation_started_count = 0;
211 _vm_operation_completed_count = 0;
212 _current_pending_monitor = NULL;
213 _current_pending_monitor_is_from_java = true;
214 _current_waiting_monitor = NULL;
215 _num_nested_signal = 0;
216 omFreeList = NULL ;
217 omFreeCount = 0 ;
218 omFreeProvision = 32 ;
219 omInUseList = NULL ;
220 omInUseCount = 0 ;
221
222 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
223 _suspend_flags = 0;
224
225 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
226 _hashStateX = os::random() ;
227 _hashStateY = 842502087 ;
228 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
229 _hashStateW = 273326509 ;
230
231 _OnTrap = 0 ;
232 _schedctl = NULL ;
233 _Stalled = 0 ;
234 _TypeTag = 0x2BAD ;
235
236 // Many of the following fields are effectively final - immutable
237 // Note that nascent threads can't use the Native Monitor-Mutex
238 // construct until the _MutexEvent is initialized ...
239 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
240 // we might instead use a stack of ParkEvents that we could provision on-demand.
241 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
242 // and ::Release()
243 _ParkEvent = ParkEvent::Allocate (this) ;
244 _SleepEvent = ParkEvent::Allocate (this) ;
245 _MutexEvent = ParkEvent::Allocate (this) ;
246 _MuxEvent = ParkEvent::Allocate (this) ;
247
248 #ifdef CHECK_UNHANDLED_OOPS
249 if (CheckUnhandledOops) {
250 _unhandled_oops = new UnhandledOops(this);
251 }
252 #endif // CHECK_UNHANDLED_OOPS
253 #ifdef ASSERT
254 if (UseBiasedLocking) {
255 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
256 assert(this == _real_malloc_address ||
257 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
258 "bug in forced alignment of thread objects");
259 }
260 #endif /* ASSERT */
261 }
262
263 void Thread::initialize_thread_local_storage() {
264 // Note: Make sure this method only calls
265 // non-blocking operations. Otherwise, it might not work
266 // with the thread-startup/safepoint interaction.
267
268 // During Java thread startup, safepoint code should allow this
269 // method to complete because it may need to allocate memory to
270 // store information for the new thread.
271
272 // initialize structure dependent on thread local storage
273 ThreadLocalStorage::set_thread(this);
274
275 // set up any platform-specific state.
276 os::initialize_thread();
277
278 }
279
280 void Thread::record_stack_base_and_size() {
281 set_stack_base(os::current_stack_base());
282 set_stack_size(os::current_stack_size());
283 }
284
285
286 Thread::~Thread() {
287 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
288 ObjectSynchronizer::omFlush (this) ;
289
290 // deallocate data structures
291 delete resource_area();
292 // since the handle marks are using the handle area, we have to deallocated the root
293 // handle mark before deallocating the thread's handle area,
294 assert(last_handle_mark() != NULL, "check we have an element");
295 delete last_handle_mark();
296 assert(last_handle_mark() == NULL, "check we have reached the end");
297
298 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
299 // We NULL out the fields for good hygiene.
300 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
301 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
302 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
303 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
304
305 delete handle_area();
306
307 // osthread() can be NULL, if creation of thread failed.
308 if (osthread() != NULL) os::free_thread(osthread());
309
310 delete _SR_lock;
311
312 // clear thread local storage if the Thread is deleting itself
313 if (this == Thread::current()) {
314 ThreadLocalStorage::set_thread(NULL);
315 } else {
316 // In the case where we're not the current thread, invalidate all the
317 // caches in case some code tries to get the current thread or the
318 // thread that was destroyed, and gets stale information.
319 ThreadLocalStorage::invalidate_all();
320 }
321 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
322 }
323
324 // NOTE: dummy function for assertion purpose.
325 void Thread::run() {
326 ShouldNotReachHere();
327 }
328
329 #ifdef ASSERT
330 // Private method to check for dangling thread pointer
331 void check_for_dangling_thread_pointer(Thread *thread) {
332 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
333 "possibility of dangling Thread pointer");
334 }
335 #endif
336
337
338 #ifndef PRODUCT
339 // Tracing method for basic thread operations
340 void Thread::trace(const char* msg, const Thread* const thread) {
341 if (!TraceThreadEvents) return;
342 ResourceMark rm;
343 ThreadCritical tc;
344 const char *name = "non-Java thread";
345 int prio = -1;
346 if (thread->is_Java_thread()
347 && !thread->is_Compiler_thread()) {
348 // The Threads_lock must be held to get information about
349 // this thread but may not be in some situations when
350 // tracing thread events.
351 bool release_Threads_lock = false;
352 if (!Threads_lock->owned_by_self()) {
353 Threads_lock->lock();
354 release_Threads_lock = true;
355 }
356 JavaThread* jt = (JavaThread *)thread;
357 name = (char *)jt->get_thread_name();
358 oop thread_oop = jt->threadObj();
359 if (thread_oop != NULL) {
360 prio = java_lang_Thread::priority(thread_oop);
361 }
362 if (release_Threads_lock) {
363 Threads_lock->unlock();
364 }
365 }
366 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
367 }
368 #endif
369
370
371 ThreadPriority Thread::get_priority(const Thread* const thread) {
372 trace("get priority", thread);
373 ThreadPriority priority;
374 // Can return an error!
375 (void)os::get_priority(thread, priority);
376 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
377 return priority;
378 }
379
380 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
381 trace("set priority", thread);
382 debug_only(check_for_dangling_thread_pointer(thread);)
383 // Can return an error!
384 (void)os::set_priority(thread, priority);
385 }
386
387
388 void Thread::start(Thread* thread) {
389 trace("start", thread);
390 // Start is different from resume in that its safety is guaranteed by context or
391 // being called from a Java method synchronized on the Thread object.
392 if (!DisableStartThread) {
393 if (thread->is_Java_thread()) {
394 // Initialize the thread state to RUNNABLE before starting this thread.
395 // Can not set it after the thread started because we do not know the
396 // exact thread state at that time. It could be in MONITOR_WAIT or
397 // in SLEEPING or some other state.
398 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
399 java_lang_Thread::RUNNABLE);
400 }
401 os::start_thread(thread);
402 }
403 }
404
405 // Enqueue a VM_Operation to do the job for us - sometime later
406 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
407 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
408 VMThread::execute(vm_stop);
409 }
410
411
412 //
413 // Check if an external suspend request has completed (or has been
414 // cancelled). Returns true if the thread is externally suspended and
415 // false otherwise.
416 //
417 // The bits parameter returns information about the code path through
418 // the routine. Useful for debugging:
419 //
420 // set in is_ext_suspend_completed():
421 // 0x00000001 - routine was entered
422 // 0x00000010 - routine return false at end
423 // 0x00000100 - thread exited (return false)
424 // 0x00000200 - suspend request cancelled (return false)
425 // 0x00000400 - thread suspended (return true)
426 // 0x00001000 - thread is in a suspend equivalent state (return true)
427 // 0x00002000 - thread is native and walkable (return true)
428 // 0x00004000 - thread is native_trans and walkable (needed retry)
429 //
430 // set in wait_for_ext_suspend_completion():
431 // 0x00010000 - routine was entered
432 // 0x00020000 - suspend request cancelled before loop (return false)
433 // 0x00040000 - thread suspended before loop (return true)
434 // 0x00080000 - suspend request cancelled in loop (return false)
435 // 0x00100000 - thread suspended in loop (return true)
436 // 0x00200000 - suspend not completed during retry loop (return false)
437 //
438
439 // Helper class for tracing suspend wait debug bits.
440 //
441 // 0x00000100 indicates that the target thread exited before it could
442 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
443 // 0x00080000 each indicate a cancelled suspend request so they don't
444 // count as wait failures either.
445 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
446
447 class TraceSuspendDebugBits : public StackObj {
448 private:
449 JavaThread * jt;
450 bool is_wait;
451 bool called_by_wait; // meaningful when !is_wait
452 uint32_t * bits;
453
454 public:
455 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
456 uint32_t *_bits) {
457 jt = _jt;
458 is_wait = _is_wait;
459 called_by_wait = _called_by_wait;
460 bits = _bits;
461 }
462
463 ~TraceSuspendDebugBits() {
464 if (!is_wait) {
465 #if 1
466 // By default, don't trace bits for is_ext_suspend_completed() calls.
467 // That trace is very chatty.
468 return;
469 #else
470 if (!called_by_wait) {
471 // If tracing for is_ext_suspend_completed() is enabled, then only
472 // trace calls to it from wait_for_ext_suspend_completion()
473 return;
474 }
475 #endif
476 }
477
478 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
479 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
480 MutexLocker ml(Threads_lock); // needed for get_thread_name()
481 ResourceMark rm;
482
483 tty->print_cr(
484 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
485 jt->get_thread_name(), *bits);
486
487 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
488 }
489 }
490 }
491 };
492 #undef DEBUG_FALSE_BITS
493
494
495 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
496 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
497
498 bool did_trans_retry = false; // only do thread_in_native_trans retry once
499 bool do_trans_retry; // flag to force the retry
500
501 *bits |= 0x00000001;
502
503 do {
504 do_trans_retry = false;
505
506 if (is_exiting()) {
507 // Thread is in the process of exiting. This is always checked
508 // first to reduce the risk of dereferencing a freed JavaThread.
509 *bits |= 0x00000100;
510 return false;
511 }
512
513 if (!is_external_suspend()) {
514 // Suspend request is cancelled. This is always checked before
515 // is_ext_suspended() to reduce the risk of a rogue resume
516 // confusing the thread that made the suspend request.
517 *bits |= 0x00000200;
518 return false;
519 }
520
521 if (is_ext_suspended()) {
522 // thread is suspended
523 *bits |= 0x00000400;
524 return true;
525 }
526
527 // Now that we no longer do hard suspends of threads running
528 // native code, the target thread can be changing thread state
529 // while we are in this routine:
530 //
531 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
532 //
533 // We save a copy of the thread state as observed at this moment
534 // and make our decision about suspend completeness based on the
535 // copy. This closes the race where the thread state is seen as
536 // _thread_in_native_trans in the if-thread_blocked check, but is
537 // seen as _thread_blocked in if-thread_in_native_trans check.
538 JavaThreadState save_state = thread_state();
539
540 if (save_state == _thread_blocked && is_suspend_equivalent()) {
541 // If the thread's state is _thread_blocked and this blocking
542 // condition is known to be equivalent to a suspend, then we can
543 // consider the thread to be externally suspended. This means that
544 // the code that sets _thread_blocked has been modified to do
545 // self-suspension if the blocking condition releases. We also
546 // used to check for CONDVAR_WAIT here, but that is now covered by
547 // the _thread_blocked with self-suspension check.
548 //
549 // Return true since we wouldn't be here unless there was still an
550 // external suspend request.
551 *bits |= 0x00001000;
552 return true;
553 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
554 // Threads running native code will self-suspend on native==>VM/Java
555 // transitions. If its stack is walkable (should always be the case
556 // unless this function is called before the actual java_suspend()
557 // call), then the wait is done.
558 *bits |= 0x00002000;
559 return true;
560 } else if (!called_by_wait && !did_trans_retry &&
561 save_state == _thread_in_native_trans &&
562 frame_anchor()->walkable()) {
563 // The thread is transitioning from thread_in_native to another
564 // thread state. check_safepoint_and_suspend_for_native_trans()
565 // will force the thread to self-suspend. If it hasn't gotten
566 // there yet we may have caught the thread in-between the native
567 // code check above and the self-suspend. Lucky us. If we were
568 // called by wait_for_ext_suspend_completion(), then it
569 // will be doing the retries so we don't have to.
570 //
571 // Since we use the saved thread state in the if-statement above,
572 // there is a chance that the thread has already transitioned to
573 // _thread_blocked by the time we get here. In that case, we will
574 // make a single unnecessary pass through the logic below. This
575 // doesn't hurt anything since we still do the trans retry.
576
577 *bits |= 0x00004000;
578
579 // Once the thread leaves thread_in_native_trans for another
580 // thread state, we break out of this retry loop. We shouldn't
581 // need this flag to prevent us from getting back here, but
582 // sometimes paranoia is good.
583 did_trans_retry = true;
584
585 // We wait for the thread to transition to a more usable state.
586 for (int i = 1; i <= SuspendRetryCount; i++) {
587 // We used to do an "os::yield_all(i)" call here with the intention
588 // that yielding would increase on each retry. However, the parameter
589 // is ignored on Linux which means the yield didn't scale up. Waiting
590 // on the SR_lock below provides a much more predictable scale up for
591 // the delay. It also provides a simple/direct point to check for any
592 // safepoint requests from the VMThread
593
594 // temporarily drops SR_lock while doing wait with safepoint check
595 // (if we're a JavaThread - the WatcherThread can also call this)
596 // and increase delay with each retry
597 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
598
599 // check the actual thread state instead of what we saved above
600 if (thread_state() != _thread_in_native_trans) {
601 // the thread has transitioned to another thread state so
602 // try all the checks (except this one) one more time.
603 do_trans_retry = true;
604 break;
605 }
606 } // end retry loop
607
608
609 }
610 } while (do_trans_retry);
611
612 *bits |= 0x00000010;
613 return false;
614 }
615
616 //
617 // Wait for an external suspend request to complete (or be cancelled).
618 // Returns true if the thread is externally suspended and false otherwise.
619 //
620 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
621 uint32_t *bits) {
622 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
623 false /* !called_by_wait */, bits);
624
625 // local flag copies to minimize SR_lock hold time
626 bool is_suspended;
627 bool pending;
628 uint32_t reset_bits;
629
630 // set a marker so is_ext_suspend_completed() knows we are the caller
631 *bits |= 0x00010000;
632
633 // We use reset_bits to reinitialize the bits value at the top of
634 // each retry loop. This allows the caller to make use of any
635 // unused bits for their own marking purposes.
636 reset_bits = *bits;
637
638 {
639 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
640 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
641 delay, bits);
642 pending = is_external_suspend();
643 }
644 // must release SR_lock to allow suspension to complete
645
646 if (!pending) {
647 // A cancelled suspend request is the only false return from
648 // is_ext_suspend_completed() that keeps us from entering the
649 // retry loop.
650 *bits |= 0x00020000;
651 return false;
652 }
653
654 if (is_suspended) {
655 *bits |= 0x00040000;
656 return true;
657 }
658
659 for (int i = 1; i <= retries; i++) {
660 *bits = reset_bits; // reinit to only track last retry
661
662 // We used to do an "os::yield_all(i)" call here with the intention
663 // that yielding would increase on each retry. However, the parameter
664 // is ignored on Linux which means the yield didn't scale up. Waiting
665 // on the SR_lock below provides a much more predictable scale up for
666 // the delay. It also provides a simple/direct point to check for any
667 // safepoint requests from the VMThread
668
669 {
670 MutexLocker ml(SR_lock());
671 // wait with safepoint check (if we're a JavaThread - the WatcherThread
672 // can also call this) and increase delay with each retry
673 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
674
675 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
676 delay, bits);
677
678 // It is possible for the external suspend request to be cancelled
679 // (by a resume) before the actual suspend operation is completed.
680 // Refresh our local copy to see if we still need to wait.
681 pending = is_external_suspend();
682 }
683
684 if (!pending) {
685 // A cancelled suspend request is the only false return from
686 // is_ext_suspend_completed() that keeps us from staying in the
687 // retry loop.
688 *bits |= 0x00080000;
689 return false;
690 }
691
692 if (is_suspended) {
693 *bits |= 0x00100000;
694 return true;
695 }
696 } // end retry loop
697
698 // thread did not suspend after all our retries
699 *bits |= 0x00200000;
700 return false;
701 }
702
703 #ifndef PRODUCT
704 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
705
706 // This should not need to be atomic as the only way for simultaneous
707 // updates is via interrupts. Even then this should be rare or non-existant
708 // and we don't care that much anyway.
709
710 int index = _jmp_ring_index;
711 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
712 _jmp_ring[index]._target = (intptr_t) target;
713 _jmp_ring[index]._instruction = (intptr_t) instr;
714 _jmp_ring[index]._file = file;
715 _jmp_ring[index]._line = line;
716 }
717 #endif /* PRODUCT */
718
719 // Called by flat profiler
720 // Callers have already called wait_for_ext_suspend_completion
721 // The assertion for that is currently too complex to put here:
722 bool JavaThread::profile_last_Java_frame(frame* _fr) {
723 bool gotframe = false;
724 // self suspension saves needed state.
725 if (has_last_Java_frame() && _anchor.walkable()) {
726 *_fr = pd_last_frame();
727 gotframe = true;
728 }
729 return gotframe;
730 }
731
732 void Thread::interrupt(Thread* thread) {
733 trace("interrupt", thread);
734 debug_only(check_for_dangling_thread_pointer(thread);)
735 os::interrupt(thread);
736 }
737
738 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
739 trace("is_interrupted", thread);
740 debug_only(check_for_dangling_thread_pointer(thread);)
741 // Note: If clear_interrupted==false, this simply fetches and
742 // returns the value of the field osthread()->interrupted().
743 return os::is_interrupted(thread, clear_interrupted);
744 }
745
746
747 // GC Support
748 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
749 jint thread_parity = _oops_do_parity;
750 if (thread_parity != strong_roots_parity) {
751 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
752 if (res == thread_parity) {
753 return true;
754 } else {
755 guarantee(res == strong_roots_parity, "Or else what?");
756 assert(SharedHeap::heap()->n_par_threads() > 0,
757 "Should only fail when parallel.");
758 return false;
759 }
760 }
761 assert(SharedHeap::heap()->n_par_threads() > 0,
762 "Should only fail when parallel.");
763 return false;
764 }
765
766 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
767 active_handles()->oops_do(f);
768 // Do oop for ThreadShadow
769 f->do_oop((oop*)&_pending_exception);
770 handle_area()->oops_do(f);
771 }
772
773 void Thread::nmethods_do(CodeBlobClosure* cf) {
774 // no nmethods in a generic thread...
775 }
776
777 void Thread::print_on(outputStream* st) const {
778 // get_priority assumes osthread initialized
779 if (osthread() != NULL) {
780 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
781 osthread()->print_on(st);
782 }
783 debug_only(if (WizardMode) print_owned_locks_on(st);)
784 }
785
786 // Thread::print_on_error() is called by fatal error handler. Don't use
787 // any lock or allocate memory.
788 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
789 if (is_VM_thread()) st->print("VMThread");
790 else if (is_Compiler_thread()) st->print("CompilerThread");
791 else if (is_Java_thread()) st->print("JavaThread");
792 else if (is_GC_task_thread()) st->print("GCTaskThread");
793 else if (is_Watcher_thread()) st->print("WatcherThread");
794 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
795 else st->print("Thread");
796
797 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
798 _stack_base - _stack_size, _stack_base);
799
800 if (osthread()) {
801 st->print(" [id=%d]", osthread()->thread_id());
802 }
803 }
804
805 #ifdef ASSERT
806 void Thread::print_owned_locks_on(outputStream* st) const {
807 Monitor *cur = _owned_locks;
808 if (cur == NULL) {
809 st->print(" (no locks) ");
810 } else {
811 st->print_cr(" Locks owned:");
812 while(cur) {
813 cur->print_on(st);
814 cur = cur->next();
815 }
816 }
817 }
818
819 static int ref_use_count = 0;
820
821 bool Thread::owns_locks_but_compiled_lock() const {
822 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
823 if (cur != Compile_lock) return true;
824 }
825 return false;
826 }
827
828
829 #endif
830
831 #ifndef PRODUCT
832
833 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
834 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
835 // no threads which allow_vm_block's are held
836 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
837 // Check if current thread is allowed to block at a safepoint
838 if (!(_allow_safepoint_count == 0))
839 fatal("Possible safepoint reached by thread that does not allow it");
840 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
841 fatal("LEAF method calling lock?");
842 }
843
844 #ifdef ASSERT
845 if (potential_vm_operation && is_Java_thread()
846 && !Universe::is_bootstrapping()) {
847 // Make sure we do not hold any locks that the VM thread also uses.
848 // This could potentially lead to deadlocks
849 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
850 // Threads_lock is special, since the safepoint synchronization will not start before this is
851 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
852 // since it is used to transfer control between JavaThreads and the VMThread
853 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
854 if ( (cur->allow_vm_block() &&
855 cur != Threads_lock &&
856 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
857 cur != VMOperationRequest_lock &&
858 cur != VMOperationQueue_lock) ||
859 cur->rank() == Mutex::special) {
860 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
861 }
862 }
863 }
864
865 if (GCALotAtAllSafepoints) {
866 // We could enter a safepoint here and thus have a gc
867 InterfaceSupport::check_gc_alot();
868 }
869 #endif
870 }
871 #endif
872
873 bool Thread::is_in_stack(address adr) const {
874 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
875 address end = os::current_stack_pointer();
876 if (stack_base() >= adr && adr >= end) return true;
877
878 return false;
879 }
880
881
882 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
883 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
884 // used for compilation in the future. If that change is made, the need for these methods
885 // should be revisited, and they should be removed if possible.
886
887 bool Thread::is_lock_owned(address adr) const {
888 return on_local_stack(adr);
889 }
890
891 bool Thread::set_as_starting_thread() {
892 // NOTE: this must be called inside the main thread.
893 return os::create_main_thread((JavaThread*)this);
894 }
895
896 static void initialize_class(Symbol* class_name, TRAPS) {
897 klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
898 instanceKlass::cast(klass)->initialize(CHECK);
899 }
900
901
902 // Creates the initial ThreadGroup
903 static Handle create_initial_thread_group(TRAPS) {
904 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
905 instanceKlassHandle klass (THREAD, k);
906
907 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
908 {
909 JavaValue result(T_VOID);
910 JavaCalls::call_special(&result,
911 system_instance,
912 klass,
913 vmSymbols::object_initializer_name(),
914 vmSymbols::void_method_signature(),
915 CHECK_NH);
916 }
917 Universe::set_system_thread_group(system_instance());
918
919 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
920 {
921 JavaValue result(T_VOID);
922 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
923 JavaCalls::call_special(&result,
924 main_instance,
925 klass,
926 vmSymbols::object_initializer_name(),
927 vmSymbols::threadgroup_string_void_signature(),
928 system_instance,
929 string,
930 CHECK_NH);
931 }
932 return main_instance;
933 }
934
935 // Creates the initial Thread
936 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
937 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
938 instanceKlassHandle klass (THREAD, k);
939 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
940
941 java_lang_Thread::set_thread(thread_oop(), thread);
942 java_lang_Thread::set_priority(thread_oop(), NormPriority);
943 thread->set_threadObj(thread_oop());
944
945 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
946
947 JavaValue result(T_VOID);
948 JavaCalls::call_special(&result, thread_oop,
949 klass,
950 vmSymbols::object_initializer_name(),
951 vmSymbols::threadgroup_string_void_signature(),
952 thread_group,
953 string,
954 CHECK_NULL);
955 return thread_oop();
956 }
957
958 static void call_initializeSystemClass(TRAPS) {
959 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
960 instanceKlassHandle klass (THREAD, k);
961
962 JavaValue result(T_VOID);
963 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
964 vmSymbols::void_method_signature(), CHECK);
965 }
966
967 // General purpose hook into Java code, run once when the VM is initialized.
968 // The Java library method itself may be changed independently from the VM.
969 static void call_postVMInitHook(TRAPS) {
970 klassOop k = SystemDictionary::sun_misc_PostVMInitHook_klass();
971 instanceKlassHandle klass (THREAD, k);
972 if (klass.not_null()) {
973 JavaValue result(T_VOID);
974 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
975 vmSymbols::void_method_signature(),
976 CHECK);
977 }
978 }
979
980 static void reset_vm_info_property(TRAPS) {
981 // the vm info string
982 ResourceMark rm(THREAD);
983 const char *vm_info = VM_Version::vm_info_string();
984
985 // java.lang.System class
986 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
987 instanceKlassHandle klass (THREAD, k);
988
989 // setProperty arguments
990 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
991 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
992
993 // return value
994 JavaValue r(T_OBJECT);
995
996 // public static String setProperty(String key, String value);
997 JavaCalls::call_static(&r,
998 klass,
999 vmSymbols::setProperty_name(),
1000 vmSymbols::string_string_string_signature(),
1001 key_str,
1002 value_str,
1003 CHECK);
1004 }
1005
1006
1007 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1008 assert(thread_group.not_null(), "thread group should be specified");
1009 assert(threadObj() == NULL, "should only create Java thread object once");
1010
1011 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1012 instanceKlassHandle klass (THREAD, k);
1013 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1014
1015 java_lang_Thread::set_thread(thread_oop(), this);
1016 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1017 set_threadObj(thread_oop());
1018
1019 JavaValue result(T_VOID);
1020 if (thread_name != NULL) {
1021 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1022 // Thread gets assigned specified name and null target
1023 JavaCalls::call_special(&result,
1024 thread_oop,
1025 klass,
1026 vmSymbols::object_initializer_name(),
1027 vmSymbols::threadgroup_string_void_signature(),
1028 thread_group, // Argument 1
1029 name, // Argument 2
1030 THREAD);
1031 } else {
1032 // Thread gets assigned name "Thread-nnn" and null target
1033 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1034 JavaCalls::call_special(&result,
1035 thread_oop,
1036 klass,
1037 vmSymbols::object_initializer_name(),
1038 vmSymbols::threadgroup_runnable_void_signature(),
1039 thread_group, // Argument 1
1040 Handle(), // Argument 2
1041 THREAD);
1042 }
1043
1044
1045 if (daemon) {
1046 java_lang_Thread::set_daemon(thread_oop());
1047 }
1048
1049 if (HAS_PENDING_EXCEPTION) {
1050 return;
1051 }
1052
1053 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1054 Handle threadObj(this, this->threadObj());
1055
1056 JavaCalls::call_special(&result,
1057 thread_group,
1058 group,
1059 vmSymbols::add_method_name(),
1060 vmSymbols::thread_void_signature(),
1061 threadObj, // Arg 1
1062 THREAD);
1063
1064
1065 }
1066
1067 // NamedThread -- non-JavaThread subclasses with multiple
1068 // uniquely named instances should derive from this.
1069 NamedThread::NamedThread() : Thread() {
1070 _name = NULL;
1071 _processed_thread = NULL;
1072 }
1073
1074 NamedThread::~NamedThread() {
1075 if (_name != NULL) {
1076 FREE_C_HEAP_ARRAY(char, _name);
1077 _name = NULL;
1078 }
1079 }
1080
1081 void NamedThread::set_name(const char* format, ...) {
1082 guarantee(_name == NULL, "Only get to set name once.");
1083 _name = NEW_C_HEAP_ARRAY(char, max_name_len);
1084 guarantee(_name != NULL, "alloc failure");
1085 va_list ap;
1086 va_start(ap, format);
1087 jio_vsnprintf(_name, max_name_len, format, ap);
1088 va_end(ap);
1089 }
1090
1091 // ======= WatcherThread ========
1092
1093 // The watcher thread exists to simulate timer interrupts. It should
1094 // be replaced by an abstraction over whatever native support for
1095 // timer interrupts exists on the platform.
1096
1097 WatcherThread* WatcherThread::_watcher_thread = NULL;
1098 volatile bool WatcherThread::_should_terminate = false;
1099
1100 WatcherThread::WatcherThread() : Thread() {
1101 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1102 if (os::create_thread(this, os::watcher_thread)) {
1103 _watcher_thread = this;
1104
1105 // Set the watcher thread to the highest OS priority which should not be
1106 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1107 // is created. The only normal thread using this priority is the reference
1108 // handler thread, which runs for very short intervals only.
1109 // If the VMThread's priority is not lower than the WatcherThread profiling
1110 // will be inaccurate.
1111 os::set_priority(this, MaxPriority);
1112 if (!DisableStartThread) {
1113 os::start_thread(this);
1114 }
1115 }
1116 }
1117
1118 void WatcherThread::run() {
1119 assert(this == watcher_thread(), "just checking");
1120
1121 this->record_stack_base_and_size();
1122 this->initialize_thread_local_storage();
1123 this->set_active_handles(JNIHandleBlock::allocate_block());
1124 while(!_should_terminate) {
1125 assert(watcher_thread() == Thread::current(), "thread consistency check");
1126 assert(watcher_thread() == this, "thread consistency check");
1127
1128 // Calculate how long it'll be until the next PeriodicTask work
1129 // should be done, and sleep that amount of time.
1130 size_t time_to_wait = PeriodicTask::time_to_wait();
1131
1132 // we expect this to timeout - we only ever get unparked when
1133 // we should terminate
1134 {
1135 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1136
1137 jlong prev_time = os::javaTimeNanos();
1138 for (;;) {
1139 int res= _SleepEvent->park(time_to_wait);
1140 if (res == OS_TIMEOUT || _should_terminate)
1141 break;
1142 // spurious wakeup of some kind
1143 jlong now = os::javaTimeNanos();
1144 time_to_wait -= (now - prev_time) / 1000000;
1145 if (time_to_wait <= 0)
1146 break;
1147 prev_time = now;
1148 }
1149 }
1150
1151 if (is_error_reported()) {
1152 // A fatal error has happened, the error handler(VMError::report_and_die)
1153 // should abort JVM after creating an error log file. However in some
1154 // rare cases, the error handler itself might deadlock. Here we try to
1155 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1156 //
1157 // This code is in WatcherThread because WatcherThread wakes up
1158 // periodically so the fatal error handler doesn't need to do anything;
1159 // also because the WatcherThread is less likely to crash than other
1160 // threads.
1161
1162 for (;;) {
1163 if (!ShowMessageBoxOnError
1164 && (OnError == NULL || OnError[0] == '\0')
1165 && Arguments::abort_hook() == NULL) {
1166 os::sleep(this, 2 * 60 * 1000, false);
1167 fdStream err(defaultStream::output_fd());
1168 err.print_raw_cr("# [ timer expired, abort... ]");
1169 // skip atexit/vm_exit/vm_abort hooks
1170 os::die();
1171 }
1172
1173 // Wake up 5 seconds later, the fatal handler may reset OnError or
1174 // ShowMessageBoxOnError when it is ready to abort.
1175 os::sleep(this, 5 * 1000, false);
1176 }
1177 }
1178
1179 PeriodicTask::real_time_tick(time_to_wait);
1180
1181 // If we have no more tasks left due to dynamic disenrollment,
1182 // shut down the thread since we don't currently support dynamic enrollment
1183 if (PeriodicTask::num_tasks() == 0) {
1184 _should_terminate = true;
1185 }
1186 }
1187
1188 // Signal that it is terminated
1189 {
1190 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1191 _watcher_thread = NULL;
1192 Terminator_lock->notify();
1193 }
1194
1195 // Thread destructor usually does this..
1196 ThreadLocalStorage::set_thread(NULL);
1197 }
1198
1199 void WatcherThread::start() {
1200 if (watcher_thread() == NULL) {
1201 _should_terminate = false;
1202 // Create the single instance of WatcherThread
1203 new WatcherThread();
1204 }
1205 }
1206
1207 void WatcherThread::stop() {
1208 // it is ok to take late safepoints here, if needed
1209 MutexLocker mu(Terminator_lock);
1210 _should_terminate = true;
1211 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1212
1213 Thread* watcher = watcher_thread();
1214 if (watcher != NULL)
1215 watcher->_SleepEvent->unpark();
1216
1217 while(watcher_thread() != NULL) {
1218 // This wait should make safepoint checks, wait without a timeout,
1219 // and wait as a suspend-equivalent condition.
1220 //
1221 // Note: If the FlatProfiler is running, then this thread is waiting
1222 // for the WatcherThread to terminate and the WatcherThread, via the
1223 // FlatProfiler task, is waiting for the external suspend request on
1224 // this thread to complete. wait_for_ext_suspend_completion() will
1225 // eventually timeout, but that takes time. Making this wait a
1226 // suspend-equivalent condition solves that timeout problem.
1227 //
1228 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1229 Mutex::_as_suspend_equivalent_flag);
1230 }
1231 }
1232
1233 void WatcherThread::print_on(outputStream* st) const {
1234 st->print("\"%s\" ", name());
1235 Thread::print_on(st);
1236 st->cr();
1237 }
1238
1239 // ======= JavaThread ========
1240
1241 // A JavaThread is a normal Java thread
1242
1243 void JavaThread::initialize() {
1244 // Initialize fields
1245
1246 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1247 set_claimed_par_id(-1);
1248
1249 set_saved_exception_pc(NULL);
1250 set_threadObj(NULL);
1251 _anchor.clear();
1252 set_entry_point(NULL);
1253 set_jni_functions(jni_functions());
1254 set_callee_target(NULL);
1255 set_vm_result(NULL);
1256 set_vm_result_2(NULL);
1257 set_vframe_array_head(NULL);
1258 set_vframe_array_last(NULL);
1259 set_deferred_locals(NULL);
1260 set_deopt_mark(NULL);
1261 set_deopt_nmethod(NULL);
1262 clear_must_deopt_id();
1263 set_monitor_chunks(NULL);
1264 set_next(NULL);
1265 set_thread_state(_thread_new);
1266 _terminated = _not_terminated;
1267 _privileged_stack_top = NULL;
1268 _array_for_gc = NULL;
1269 _suspend_equivalent = false;
1270 _in_deopt_handler = 0;
1271 _doing_unsafe_access = false;
1272 _stack_guard_state = stack_guard_unused;
1273 _exception_oop = NULL;
1274 _exception_pc = 0;
1275 _exception_handler_pc = 0;
1276 _exception_stack_size = 0;
1277 _is_method_handle_return = 0;
1278 _jvmti_thread_state= NULL;
1279 _should_post_on_exceptions_flag = JNI_FALSE;
1280 _jvmti_get_loaded_classes_closure = NULL;
1281 _interp_only_mode = 0;
1282 _special_runtime_exit_condition = _no_async_condition;
1283 _pending_async_exception = NULL;
1284 _is_compiling = false;
1285 _thread_stat = NULL;
1286 _thread_stat = new ThreadStatistics();
1287 _blocked_on_compilation = false;
1288 _jni_active_critical = 0;
1289 _do_not_unlock_if_synchronized = false;
1290 _cached_monitor_info = NULL;
1291 _parker = Parker::Allocate(this) ;
1292
1293 #ifndef PRODUCT
1294 _jmp_ring_index = 0;
1295 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1296 record_jump(NULL, NULL, NULL, 0);
1297 }
1298 #endif /* PRODUCT */
1299
1300 set_thread_profiler(NULL);
1301 if (FlatProfiler::is_active()) {
1302 // This is where we would decide to either give each thread it's own profiler
1303 // or use one global one from FlatProfiler,
1304 // or up to some count of the number of profiled threads, etc.
1305 ThreadProfiler* pp = new ThreadProfiler();
1306 pp->engage();
1307 set_thread_profiler(pp);
1308 }
1309
1310 // Setup safepoint state info for this thread
1311 ThreadSafepointState::create(this);
1312
1313 debug_only(_java_call_counter = 0);
1314
1315 // JVMTI PopFrame support
1316 _popframe_condition = popframe_inactive;
1317 _popframe_preserved_args = NULL;
1318 _popframe_preserved_args_size = 0;
1319
1320 pd_initialize();
1321 }
1322
1323 #ifndef SERIALGC
1324 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1325 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1326 #endif // !SERIALGC
1327
1328 JavaThread::JavaThread(bool is_attaching) :
1329 Thread()
1330 #ifndef SERIALGC
1331 , _satb_mark_queue(&_satb_mark_queue_set),
1332 _dirty_card_queue(&_dirty_card_queue_set)
1333 #endif // !SERIALGC
1334 {
1335 initialize();
1336 _is_attaching = is_attaching;
1337 assert(_deferred_card_mark.is_empty(), "Default MemRegion ctor");
1338 }
1339
1340 bool JavaThread::reguard_stack(address cur_sp) {
1341 if (_stack_guard_state != stack_guard_yellow_disabled) {
1342 return true; // Stack already guarded or guard pages not needed.
1343 }
1344
1345 if (register_stack_overflow()) {
1346 // For those architectures which have separate register and
1347 // memory stacks, we must check the register stack to see if
1348 // it has overflowed.
1349 return false;
1350 }
1351
1352 // Java code never executes within the yellow zone: the latter is only
1353 // there to provoke an exception during stack banging. If java code
1354 // is executing there, either StackShadowPages should be larger, or
1355 // some exception code in c1, c2 or the interpreter isn't unwinding
1356 // when it should.
1357 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1358
1359 enable_stack_yellow_zone();
1360 return true;
1361 }
1362
1363 bool JavaThread::reguard_stack(void) {
1364 return reguard_stack(os::current_stack_pointer());
1365 }
1366
1367
1368 void JavaThread::block_if_vm_exited() {
1369 if (_terminated == _vm_exited) {
1370 // _vm_exited is set at safepoint, and Threads_lock is never released
1371 // we will block here forever
1372 Threads_lock->lock_without_safepoint_check();
1373 ShouldNotReachHere();
1374 }
1375 }
1376
1377
1378 // Remove this ifdef when C1 is ported to the compiler interface.
1379 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1380
1381 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1382 Thread()
1383 #ifndef SERIALGC
1384 , _satb_mark_queue(&_satb_mark_queue_set),
1385 _dirty_card_queue(&_dirty_card_queue_set)
1386 #endif // !SERIALGC
1387 {
1388 if (TraceThreadEvents) {
1389 tty->print_cr("creating thread %p", this);
1390 }
1391 initialize();
1392 _is_attaching = false;
1393 set_entry_point(entry_point);
1394 // Create the native thread itself.
1395 // %note runtime_23
1396 os::ThreadType thr_type = os::java_thread;
1397 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1398 os::java_thread;
1399 os::create_thread(this, thr_type, stack_sz);
1400
1401 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1402 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1403 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1404 // the exception consists of creating the exception object & initializing it, initialization
1405 // will leave the VM via a JavaCall and then all locks must be unlocked).
1406 //
1407 // The thread is still suspended when we reach here. Thread must be explicit started
1408 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1409 // by calling Threads:add. The reason why this is not done here, is because the thread
1410 // object must be fully initialized (take a look at JVM_Start)
1411 }
1412
1413 JavaThread::~JavaThread() {
1414 if (TraceThreadEvents) {
1415 tty->print_cr("terminate thread %p", this);
1416 }
1417
1418 // JSR166 -- return the parker to the free list
1419 Parker::Release(_parker);
1420 _parker = NULL ;
1421
1422 // Free any remaining previous UnrollBlock
1423 vframeArray* old_array = vframe_array_last();
1424
1425 if (old_array != NULL) {
1426 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1427 old_array->set_unroll_block(NULL);
1428 delete old_info;
1429 delete old_array;
1430 }
1431
1432 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1433 if (deferred != NULL) {
1434 // This can only happen if thread is destroyed before deoptimization occurs.
1435 assert(deferred->length() != 0, "empty array!");
1436 do {
1437 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1438 deferred->remove_at(0);
1439 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1440 delete dlv;
1441 } while (deferred->length() != 0);
1442 delete deferred;
1443 }
1444
1445 // All Java related clean up happens in exit
1446 ThreadSafepointState::destroy(this);
1447 if (_thread_profiler != NULL) delete _thread_profiler;
1448 if (_thread_stat != NULL) delete _thread_stat;
1449 }
1450
1451
1452 // The first routine called by a new Java thread
1453 void JavaThread::run() {
1454 // initialize thread-local alloc buffer related fields
1455 this->initialize_tlab();
1456
1457 // used to test validitity of stack trace backs
1458 this->record_base_of_stack_pointer();
1459
1460 // Record real stack base and size.
1461 this->record_stack_base_and_size();
1462
1463 // Initialize thread local storage; set before calling MutexLocker
1464 this->initialize_thread_local_storage();
1465
1466 this->create_stack_guard_pages();
1467
1468 this->cache_global_variables();
1469
1470 // Thread is now sufficient initialized to be handled by the safepoint code as being
1471 // in the VM. Change thread state from _thread_new to _thread_in_vm
1472 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1473
1474 assert(JavaThread::current() == this, "sanity check");
1475 assert(!Thread::current()->owns_locks(), "sanity check");
1476
1477 DTRACE_THREAD_PROBE(start, this);
1478
1479 // This operation might block. We call that after all safepoint checks for a new thread has
1480 // been completed.
1481 this->set_active_handles(JNIHandleBlock::allocate_block());
1482
1483 if (JvmtiExport::should_post_thread_life()) {
1484 JvmtiExport::post_thread_start(this);
1485 }
1486
1487 // We call another function to do the rest so we are sure that the stack addresses used
1488 // from there will be lower than the stack base just computed
1489 thread_main_inner();
1490
1491 // Note, thread is no longer valid at this point!
1492 }
1493
1494
1495 void JavaThread::thread_main_inner() {
1496 assert(JavaThread::current() == this, "sanity check");
1497 assert(this->threadObj() != NULL, "just checking");
1498
1499 // Execute thread entry point unless this thread has a pending exception
1500 // or has been stopped before starting.
1501 // Note: Due to JVM_StopThread we can have pending exceptions already!
1502 if (!this->has_pending_exception() &&
1503 !java_lang_Thread::is_stillborn(this->threadObj())) {
1504 HandleMark hm(this);
1505 this->entry_point()(this, this);
1506 }
1507
1508 DTRACE_THREAD_PROBE(stop, this);
1509
1510 this->exit(false);
1511 delete this;
1512 }
1513
1514
1515 static void ensure_join(JavaThread* thread) {
1516 // We do not need to grap the Threads_lock, since we are operating on ourself.
1517 Handle threadObj(thread, thread->threadObj());
1518 assert(threadObj.not_null(), "java thread object must exist");
1519 ObjectLocker lock(threadObj, thread);
1520 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1521 thread->clear_pending_exception();
1522 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1523 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1524 // Clear the native thread instance - this makes isAlive return false and allows the join()
1525 // to complete once we've done the notify_all below
1526 java_lang_Thread::set_thread(threadObj(), NULL);
1527 lock.notify_all(thread);
1528 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1529 thread->clear_pending_exception();
1530 }
1531
1532
1533 // For any new cleanup additions, please check to see if they need to be applied to
1534 // cleanup_failed_attach_current_thread as well.
1535 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1536 assert(this == JavaThread::current(), "thread consistency check");
1537 if (!InitializeJavaLangSystem) return;
1538
1539 HandleMark hm(this);
1540 Handle uncaught_exception(this, this->pending_exception());
1541 this->clear_pending_exception();
1542 Handle threadObj(this, this->threadObj());
1543 assert(threadObj.not_null(), "Java thread object should be created");
1544
1545 if (get_thread_profiler() != NULL) {
1546 get_thread_profiler()->disengage();
1547 ResourceMark rm;
1548 get_thread_profiler()->print(get_thread_name());
1549 }
1550
1551
1552 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1553 {
1554 EXCEPTION_MARK;
1555
1556 CLEAR_PENDING_EXCEPTION;
1557 }
1558 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1559 // has to be fixed by a runtime query method
1560 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1561 // JSR-166: change call from from ThreadGroup.uncaughtException to
1562 // java.lang.Thread.dispatchUncaughtException
1563 if (uncaught_exception.not_null()) {
1564 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1565 Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT",
1566 (address)uncaught_exception(), (address)threadObj(), (address)group());
1567 {
1568 EXCEPTION_MARK;
1569 // Check if the method Thread.dispatchUncaughtException() exists. If so
1570 // call it. Otherwise we have an older library without the JSR-166 changes,
1571 // so call ThreadGroup.uncaughtException()
1572 KlassHandle recvrKlass(THREAD, threadObj->klass());
1573 CallInfo callinfo;
1574 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1575 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1576 vmSymbols::dispatchUncaughtException_name(),
1577 vmSymbols::throwable_void_signature(),
1578 KlassHandle(), false, false, THREAD);
1579 CLEAR_PENDING_EXCEPTION;
1580 methodHandle method = callinfo.selected_method();
1581 if (method.not_null()) {
1582 JavaValue result(T_VOID);
1583 JavaCalls::call_virtual(&result,
1584 threadObj, thread_klass,
1585 vmSymbols::dispatchUncaughtException_name(),
1586 vmSymbols::throwable_void_signature(),
1587 uncaught_exception,
1588 THREAD);
1589 } else {
1590 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1591 JavaValue result(T_VOID);
1592 JavaCalls::call_virtual(&result,
1593 group, thread_group,
1594 vmSymbols::uncaughtException_name(),
1595 vmSymbols::thread_throwable_void_signature(),
1596 threadObj, // Arg 1
1597 uncaught_exception, // Arg 2
1598 THREAD);
1599 }
1600 if (HAS_PENDING_EXCEPTION) {
1601 ResourceMark rm(this);
1602 jio_fprintf(defaultStream::error_stream(),
1603 "\nException: %s thrown from the UncaughtExceptionHandler"
1604 " in thread \"%s\"\n",
1605 Klass::cast(pending_exception()->klass())->external_name(),
1606 get_thread_name());
1607 CLEAR_PENDING_EXCEPTION;
1608 }
1609 }
1610 }
1611
1612 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1613 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1614 // is deprecated anyhow.
1615 { int count = 3;
1616 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1617 EXCEPTION_MARK;
1618 JavaValue result(T_VOID);
1619 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1620 JavaCalls::call_virtual(&result,
1621 threadObj, thread_klass,
1622 vmSymbols::exit_method_name(),
1623 vmSymbols::void_method_signature(),
1624 THREAD);
1625 CLEAR_PENDING_EXCEPTION;
1626 }
1627 }
1628
1629 // notify JVMTI
1630 if (JvmtiExport::should_post_thread_life()) {
1631 JvmtiExport::post_thread_end(this);
1632 }
1633
1634 // We have notified the agents that we are exiting, before we go on,
1635 // we must check for a pending external suspend request and honor it
1636 // in order to not surprise the thread that made the suspend request.
1637 while (true) {
1638 {
1639 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1640 if (!is_external_suspend()) {
1641 set_terminated(_thread_exiting);
1642 ThreadService::current_thread_exiting(this);
1643 break;
1644 }
1645 // Implied else:
1646 // Things get a little tricky here. We have a pending external
1647 // suspend request, but we are holding the SR_lock so we
1648 // can't just self-suspend. So we temporarily drop the lock
1649 // and then self-suspend.
1650 }
1651
1652 ThreadBlockInVM tbivm(this);
1653 java_suspend_self();
1654
1655 // We're done with this suspend request, but we have to loop around
1656 // and check again. Eventually we will get SR_lock without a pending
1657 // external suspend request and will be able to mark ourselves as
1658 // exiting.
1659 }
1660 // no more external suspends are allowed at this point
1661 } else {
1662 // before_exit() has already posted JVMTI THREAD_END events
1663 }
1664
1665 // Notify waiters on thread object. This has to be done after exit() is called
1666 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1667 // group should have the destroyed bit set before waiters are notified).
1668 ensure_join(this);
1669 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1670
1671 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1672 // held by this thread must be released. A detach operation must only
1673 // get here if there are no Java frames on the stack. Therefore, any
1674 // owned monitors at this point MUST be JNI-acquired monitors which are
1675 // pre-inflated and in the monitor cache.
1676 //
1677 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1678 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1679 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1680 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1681 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1682 }
1683
1684 // These things needs to be done while we are still a Java Thread. Make sure that thread
1685 // is in a consistent state, in case GC happens
1686 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1687
1688 if (active_handles() != NULL) {
1689 JNIHandleBlock* block = active_handles();
1690 set_active_handles(NULL);
1691 JNIHandleBlock::release_block(block);
1692 }
1693
1694 if (free_handle_block() != NULL) {
1695 JNIHandleBlock* block = free_handle_block();
1696 set_free_handle_block(NULL);
1697 JNIHandleBlock::release_block(block);
1698 }
1699
1700 // These have to be removed while this is still a valid thread.
1701 remove_stack_guard_pages();
1702
1703 if (UseTLAB) {
1704 tlab().make_parsable(true); // retire TLAB
1705 }
1706
1707 if (JvmtiEnv::environments_might_exist()) {
1708 JvmtiExport::cleanup_thread(this);
1709 }
1710
1711 #ifndef SERIALGC
1712 // We must flush G1-related buffers before removing a thread from
1713 // the list of active threads.
1714 if (UseG1GC) {
1715 flush_barrier_queues();
1716 }
1717 #endif
1718
1719 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1720 Threads::remove(this);
1721 }
1722
1723 #ifndef SERIALGC
1724 // Flush G1-related queues.
1725 void JavaThread::flush_barrier_queues() {
1726 satb_mark_queue().flush();
1727 dirty_card_queue().flush();
1728 }
1729
1730 void JavaThread::initialize_queues() {
1731 assert(!SafepointSynchronize::is_at_safepoint(),
1732 "we should not be at a safepoint");
1733
1734 ObjPtrQueue& satb_queue = satb_mark_queue();
1735 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1736 // The SATB queue should have been constructed with its active
1737 // field set to false.
1738 assert(!satb_queue.is_active(), "SATB queue should not be active");
1739 assert(satb_queue.is_empty(), "SATB queue should be empty");
1740 // If we are creating the thread during a marking cycle, we should
1741 // set the active field of the SATB queue to true.
1742 if (satb_queue_set.is_active()) {
1743 satb_queue.set_active(true);
1744 }
1745
1746 DirtyCardQueue& dirty_queue = dirty_card_queue();
1747 // The dirty card queue should have been constructed with its
1748 // active field set to true.
1749 assert(dirty_queue.is_active(), "dirty card queue should be active");
1750 }
1751 #endif // !SERIALGC
1752
1753 void JavaThread::cleanup_failed_attach_current_thread() {
1754 if (get_thread_profiler() != NULL) {
1755 get_thread_profiler()->disengage();
1756 ResourceMark rm;
1757 get_thread_profiler()->print(get_thread_name());
1758 }
1759
1760 if (active_handles() != NULL) {
1761 JNIHandleBlock* block = active_handles();
1762 set_active_handles(NULL);
1763 JNIHandleBlock::release_block(block);
1764 }
1765
1766 if (free_handle_block() != NULL) {
1767 JNIHandleBlock* block = free_handle_block();
1768 set_free_handle_block(NULL);
1769 JNIHandleBlock::release_block(block);
1770 }
1771
1772 // These have to be removed while this is still a valid thread.
1773 remove_stack_guard_pages();
1774
1775 if (UseTLAB) {
1776 tlab().make_parsable(true); // retire TLAB, if any
1777 }
1778
1779 #ifndef SERIALGC
1780 if (UseG1GC) {
1781 flush_barrier_queues();
1782 }
1783 #endif
1784
1785 Threads::remove(this);
1786 delete this;
1787 }
1788
1789
1790
1791
1792 JavaThread* JavaThread::active() {
1793 Thread* thread = ThreadLocalStorage::thread();
1794 assert(thread != NULL, "just checking");
1795 if (thread->is_Java_thread()) {
1796 return (JavaThread*) thread;
1797 } else {
1798 assert(thread->is_VM_thread(), "this must be a vm thread");
1799 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1800 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1801 assert(ret->is_Java_thread(), "must be a Java thread");
1802 return ret;
1803 }
1804 }
1805
1806 bool JavaThread::is_lock_owned(address adr) const {
1807 if (Thread::is_lock_owned(adr)) return true;
1808
1809 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1810 if (chunk->contains(adr)) return true;
1811 }
1812
1813 return false;
1814 }
1815
1816
1817 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1818 chunk->set_next(monitor_chunks());
1819 set_monitor_chunks(chunk);
1820 }
1821
1822 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1823 guarantee(monitor_chunks() != NULL, "must be non empty");
1824 if (monitor_chunks() == chunk) {
1825 set_monitor_chunks(chunk->next());
1826 } else {
1827 MonitorChunk* prev = monitor_chunks();
1828 while (prev->next() != chunk) prev = prev->next();
1829 prev->set_next(chunk->next());
1830 }
1831 }
1832
1833 // JVM support.
1834
1835 // Note: this function shouldn't block if it's called in
1836 // _thread_in_native_trans state (such as from
1837 // check_special_condition_for_native_trans()).
1838 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1839
1840 if (has_last_Java_frame() && has_async_condition()) {
1841 // If we are at a polling page safepoint (not a poll return)
1842 // then we must defer async exception because live registers
1843 // will be clobbered by the exception path. Poll return is
1844 // ok because the call we a returning from already collides
1845 // with exception handling registers and so there is no issue.
1846 // (The exception handling path kills call result registers but
1847 // this is ok since the exception kills the result anyway).
1848
1849 if (is_at_poll_safepoint()) {
1850 // if the code we are returning to has deoptimized we must defer
1851 // the exception otherwise live registers get clobbered on the
1852 // exception path before deoptimization is able to retrieve them.
1853 //
1854 RegisterMap map(this, false);
1855 frame caller_fr = last_frame().sender(&map);
1856 assert(caller_fr.is_compiled_frame(), "what?");
1857 if (caller_fr.is_deoptimized_frame()) {
1858 if (TraceExceptions) {
1859 ResourceMark rm;
1860 tty->print_cr("deferred async exception at compiled safepoint");
1861 }
1862 return;
1863 }
1864 }
1865 }
1866
1867 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
1868 if (condition == _no_async_condition) {
1869 // Conditions have changed since has_special_runtime_exit_condition()
1870 // was called:
1871 // - if we were here only because of an external suspend request,
1872 // then that was taken care of above (or cancelled) so we are done
1873 // - if we were here because of another async request, then it has
1874 // been cleared between the has_special_runtime_exit_condition()
1875 // and now so again we are done
1876 return;
1877 }
1878
1879 // Check for pending async. exception
1880 if (_pending_async_exception != NULL) {
1881 // Only overwrite an already pending exception, if it is not a threadDeath.
1882 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
1883
1884 // We cannot call Exceptions::_throw(...) here because we cannot block
1885 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
1886
1887 if (TraceExceptions) {
1888 ResourceMark rm;
1889 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
1890 if (has_last_Java_frame() ) {
1891 frame f = last_frame();
1892 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
1893 }
1894 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1895 }
1896 _pending_async_exception = NULL;
1897 clear_has_async_exception();
1898 }
1899 }
1900
1901 if (check_unsafe_error &&
1902 condition == _async_unsafe_access_error && !has_pending_exception()) {
1903 condition = _no_async_condition; // done
1904 switch (thread_state()) {
1905 case _thread_in_vm:
1906 {
1907 JavaThread* THREAD = this;
1908 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1909 }
1910 case _thread_in_native:
1911 {
1912 ThreadInVMfromNative tiv(this);
1913 JavaThread* THREAD = this;
1914 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1915 }
1916 case _thread_in_Java:
1917 {
1918 ThreadInVMfromJava tiv(this);
1919 JavaThread* THREAD = this;
1920 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
1921 }
1922 default:
1923 ShouldNotReachHere();
1924 }
1925 }
1926
1927 assert(condition == _no_async_condition || has_pending_exception() ||
1928 (!check_unsafe_error && condition == _async_unsafe_access_error),
1929 "must have handled the async condition, if no exception");
1930 }
1931
1932 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
1933 //
1934 // Check for pending external suspend. Internal suspend requests do
1935 // not use handle_special_runtime_exit_condition().
1936 // If JNIEnv proxies are allowed, don't self-suspend if the target
1937 // thread is not the current thread. In older versions of jdbx, jdbx
1938 // threads could call into the VM with another thread's JNIEnv so we
1939 // can be here operating on behalf of a suspended thread (4432884).
1940 bool do_self_suspend = is_external_suspend_with_lock();
1941 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
1942 //
1943 // Because thread is external suspended the safepoint code will count
1944 // thread as at a safepoint. This can be odd because we can be here
1945 // as _thread_in_Java which would normally transition to _thread_blocked
1946 // at a safepoint. We would like to mark the thread as _thread_blocked
1947 // before calling java_suspend_self like all other callers of it but
1948 // we must then observe proper safepoint protocol. (We can't leave
1949 // _thread_blocked with a safepoint in progress). However we can be
1950 // here as _thread_in_native_trans so we can't use a normal transition
1951 // constructor/destructor pair because they assert on that type of
1952 // transition. We could do something like:
1953 //
1954 // JavaThreadState state = thread_state();
1955 // set_thread_state(_thread_in_vm);
1956 // {
1957 // ThreadBlockInVM tbivm(this);
1958 // java_suspend_self()
1959 // }
1960 // set_thread_state(_thread_in_vm_trans);
1961 // if (safepoint) block;
1962 // set_thread_state(state);
1963 //
1964 // but that is pretty messy. Instead we just go with the way the
1965 // code has worked before and note that this is the only path to
1966 // java_suspend_self that doesn't put the thread in _thread_blocked
1967 // mode.
1968
1969 frame_anchor()->make_walkable(this);
1970 java_suspend_self();
1971
1972 // We might be here for reasons in addition to the self-suspend request
1973 // so check for other async requests.
1974 }
1975
1976 if (check_asyncs) {
1977 check_and_handle_async_exceptions();
1978 }
1979 }
1980
1981 void JavaThread::send_thread_stop(oop java_throwable) {
1982 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
1983 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
1984 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
1985
1986 // Do not throw asynchronous exceptions against the compiler thread
1987 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
1988 if (is_Compiler_thread()) return;
1989
1990 {
1991 // Actually throw the Throwable against the target Thread - however
1992 // only if there is no thread death exception installed already.
1993 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
1994 // If the topmost frame is a runtime stub, then we are calling into
1995 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1996 // must deoptimize the caller before continuing, as the compiled exception handler table
1997 // may not be valid
1998 if (has_last_Java_frame()) {
1999 frame f = last_frame();
2000 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2001 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2002 RegisterMap reg_map(this, UseBiasedLocking);
2003 frame compiled_frame = f.sender(®_map);
2004 if (compiled_frame.can_be_deoptimized()) {
2005 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2006 }
2007 }
2008 }
2009
2010 // Set async. pending exception in thread.
2011 set_pending_async_exception(java_throwable);
2012
2013 if (TraceExceptions) {
2014 ResourceMark rm;
2015 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
2016 }
2017 // for AbortVMOnException flag
2018 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
2019 }
2020 }
2021
2022
2023 // Interrupt thread so it will wake up from a potential wait()
2024 Thread::interrupt(this);
2025 }
2026
2027 // External suspension mechanism.
2028 //
2029 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2030 // to any VM_locks and it is at a transition
2031 // Self-suspension will happen on the transition out of the vm.
2032 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2033 //
2034 // Guarantees on return:
2035 // + Target thread will not execute any new bytecode (that's why we need to
2036 // force a safepoint)
2037 // + Target thread will not enter any new monitors
2038 //
2039 void JavaThread::java_suspend() {
2040 { MutexLocker mu(Threads_lock);
2041 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2042 return;
2043 }
2044 }
2045
2046 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2047 if (!is_external_suspend()) {
2048 // a racing resume has cancelled us; bail out now
2049 return;
2050 }
2051
2052 // suspend is done
2053 uint32_t debug_bits = 0;
2054 // Warning: is_ext_suspend_completed() may temporarily drop the
2055 // SR_lock to allow the thread to reach a stable thread state if
2056 // it is currently in a transient thread state.
2057 if (is_ext_suspend_completed(false /* !called_by_wait */,
2058 SuspendRetryDelay, &debug_bits) ) {
2059 return;
2060 }
2061 }
2062
2063 VM_ForceSafepoint vm_suspend;
2064 VMThread::execute(&vm_suspend);
2065 }
2066
2067 // Part II of external suspension.
2068 // A JavaThread self suspends when it detects a pending external suspend
2069 // request. This is usually on transitions. It is also done in places
2070 // where continuing to the next transition would surprise the caller,
2071 // e.g., monitor entry.
2072 //
2073 // Returns the number of times that the thread self-suspended.
2074 //
2075 // Note: DO NOT call java_suspend_self() when you just want to block current
2076 // thread. java_suspend_self() is the second stage of cooperative
2077 // suspension for external suspend requests and should only be used
2078 // to complete an external suspend request.
2079 //
2080 int JavaThread::java_suspend_self() {
2081 int ret = 0;
2082
2083 // we are in the process of exiting so don't suspend
2084 if (is_exiting()) {
2085 clear_external_suspend();
2086 return ret;
2087 }
2088
2089 assert(_anchor.walkable() ||
2090 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2091 "must have walkable stack");
2092
2093 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2094
2095 assert(!this->is_ext_suspended(),
2096 "a thread trying to self-suspend should not already be suspended");
2097
2098 if (this->is_suspend_equivalent()) {
2099 // If we are self-suspending as a result of the lifting of a
2100 // suspend equivalent condition, then the suspend_equivalent
2101 // flag is not cleared until we set the ext_suspended flag so
2102 // that wait_for_ext_suspend_completion() returns consistent
2103 // results.
2104 this->clear_suspend_equivalent();
2105 }
2106
2107 // A racing resume may have cancelled us before we grabbed SR_lock
2108 // above. Or another external suspend request could be waiting for us
2109 // by the time we return from SR_lock()->wait(). The thread
2110 // that requested the suspension may already be trying to walk our
2111 // stack and if we return now, we can change the stack out from under
2112 // it. This would be a "bad thing (TM)" and cause the stack walker
2113 // to crash. We stay self-suspended until there are no more pending
2114 // external suspend requests.
2115 while (is_external_suspend()) {
2116 ret++;
2117 this->set_ext_suspended();
2118
2119 // _ext_suspended flag is cleared by java_resume()
2120 while (is_ext_suspended()) {
2121 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2122 }
2123 }
2124
2125 return ret;
2126 }
2127
2128 #ifdef ASSERT
2129 // verify the JavaThread has not yet been published in the Threads::list, and
2130 // hence doesn't need protection from concurrent access at this stage
2131 void JavaThread::verify_not_published() {
2132 if (!Threads_lock->owned_by_self()) {
2133 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2134 assert( !Threads::includes(this),
2135 "java thread shouldn't have been published yet!");
2136 }
2137 else {
2138 assert( !Threads::includes(this),
2139 "java thread shouldn't have been published yet!");
2140 }
2141 }
2142 #endif
2143
2144 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2145 // progress or when _suspend_flags is non-zero.
2146 // Current thread needs to self-suspend if there is a suspend request and/or
2147 // block if a safepoint is in progress.
2148 // Async exception ISN'T checked.
2149 // Note only the ThreadInVMfromNative transition can call this function
2150 // directly and when thread state is _thread_in_native_trans
2151 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2152 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2153
2154 JavaThread *curJT = JavaThread::current();
2155 bool do_self_suspend = thread->is_external_suspend();
2156
2157 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2158
2159 // If JNIEnv proxies are allowed, don't self-suspend if the target
2160 // thread is not the current thread. In older versions of jdbx, jdbx
2161 // threads could call into the VM with another thread's JNIEnv so we
2162 // can be here operating on behalf of a suspended thread (4432884).
2163 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2164 JavaThreadState state = thread->thread_state();
2165
2166 // We mark this thread_blocked state as a suspend-equivalent so
2167 // that a caller to is_ext_suspend_completed() won't be confused.
2168 // The suspend-equivalent state is cleared by java_suspend_self().
2169 thread->set_suspend_equivalent();
2170
2171 // If the safepoint code sees the _thread_in_native_trans state, it will
2172 // wait until the thread changes to other thread state. There is no
2173 // guarantee on how soon we can obtain the SR_lock and complete the
2174 // self-suspend request. It would be a bad idea to let safepoint wait for
2175 // too long. Temporarily change the state to _thread_blocked to
2176 // let the VM thread know that this thread is ready for GC. The problem
2177 // of changing thread state is that safepoint could happen just after
2178 // java_suspend_self() returns after being resumed, and VM thread will
2179 // see the _thread_blocked state. We must check for safepoint
2180 // after restoring the state and make sure we won't leave while a safepoint
2181 // is in progress.
2182 thread->set_thread_state(_thread_blocked);
2183 thread->java_suspend_self();
2184 thread->set_thread_state(state);
2185 // Make sure new state is seen by VM thread
2186 if (os::is_MP()) {
2187 if (UseMembar) {
2188 // Force a fence between the write above and read below
2189 OrderAccess::fence();
2190 } else {
2191 // Must use this rather than serialization page in particular on Windows
2192 InterfaceSupport::serialize_memory(thread);
2193 }
2194 }
2195 }
2196
2197 if (SafepointSynchronize::do_call_back()) {
2198 // If we are safepointing, then block the caller which may not be
2199 // the same as the target thread (see above).
2200 SafepointSynchronize::block(curJT);
2201 }
2202
2203 if (thread->is_deopt_suspend()) {
2204 thread->clear_deopt_suspend();
2205 RegisterMap map(thread, false);
2206 frame f = thread->last_frame();
2207 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2208 f = f.sender(&map);
2209 }
2210 if (f.id() == thread->must_deopt_id()) {
2211 thread->clear_must_deopt_id();
2212 f.deoptimize(thread);
2213 } else {
2214 fatal("missed deoptimization!");
2215 }
2216 }
2217 }
2218
2219 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2220 // progress or when _suspend_flags is non-zero.
2221 // Current thread needs to self-suspend if there is a suspend request and/or
2222 // block if a safepoint is in progress.
2223 // Also check for pending async exception (not including unsafe access error).
2224 // Note only the native==>VM/Java barriers can call this function and when
2225 // thread state is _thread_in_native_trans.
2226 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2227 check_safepoint_and_suspend_for_native_trans(thread);
2228
2229 if (thread->has_async_exception()) {
2230 // We are in _thread_in_native_trans state, don't handle unsafe
2231 // access error since that may block.
2232 thread->check_and_handle_async_exceptions(false);
2233 }
2234 }
2235
2236 // We need to guarantee the Threads_lock here, since resumes are not
2237 // allowed during safepoint synchronization
2238 // Can only resume from an external suspension
2239 void JavaThread::java_resume() {
2240 assert_locked_or_safepoint(Threads_lock);
2241
2242 // Sanity check: thread is gone, has started exiting or the thread
2243 // was not externally suspended.
2244 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2245 return;
2246 }
2247
2248 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2249
2250 clear_external_suspend();
2251
2252 if (is_ext_suspended()) {
2253 clear_ext_suspended();
2254 SR_lock()->notify_all();
2255 }
2256 }
2257
2258 void JavaThread::create_stack_guard_pages() {
2259 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2260 address low_addr = stack_base() - stack_size();
2261 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2262
2263 int allocate = os::allocate_stack_guard_pages();
2264 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2265
2266 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2267 warning("Attempt to allocate stack guard pages failed.");
2268 return;
2269 }
2270
2271 if (os::guard_memory((char *) low_addr, len)) {
2272 _stack_guard_state = stack_guard_enabled;
2273 } else {
2274 warning("Attempt to protect stack guard pages failed.");
2275 if (os::uncommit_memory((char *) low_addr, len)) {
2276 warning("Attempt to deallocate stack guard pages failed.");
2277 }
2278 }
2279 }
2280
2281 void JavaThread::remove_stack_guard_pages() {
2282 if (_stack_guard_state == stack_guard_unused) return;
2283 address low_addr = stack_base() - stack_size();
2284 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2285
2286 if (os::allocate_stack_guard_pages()) {
2287 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2288 _stack_guard_state = stack_guard_unused;
2289 } else {
2290 warning("Attempt to deallocate stack guard pages failed.");
2291 }
2292 } else {
2293 if (_stack_guard_state == stack_guard_unused) return;
2294 if (os::unguard_memory((char *) low_addr, len)) {
2295 _stack_guard_state = stack_guard_unused;
2296 } else {
2297 warning("Attempt to unprotect stack guard pages failed.");
2298 }
2299 }
2300 }
2301
2302 void JavaThread::enable_stack_yellow_zone() {
2303 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2304 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2305
2306 // The base notation is from the stacks point of view, growing downward.
2307 // We need to adjust it to work correctly with guard_memory()
2308 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2309
2310 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2311 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2312
2313 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2314 _stack_guard_state = stack_guard_enabled;
2315 } else {
2316 warning("Attempt to guard stack yellow zone failed.");
2317 }
2318 enable_register_stack_guard();
2319 }
2320
2321 void JavaThread::disable_stack_yellow_zone() {
2322 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2323 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2324
2325 // Simply return if called for a thread that does not use guard pages.
2326 if (_stack_guard_state == stack_guard_unused) return;
2327
2328 // The base notation is from the stacks point of view, growing downward.
2329 // We need to adjust it to work correctly with guard_memory()
2330 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2331
2332 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2333 _stack_guard_state = stack_guard_yellow_disabled;
2334 } else {
2335 warning("Attempt to unguard stack yellow zone failed.");
2336 }
2337 disable_register_stack_guard();
2338 }
2339
2340 void JavaThread::enable_stack_red_zone() {
2341 // The base notation is from the stacks point of view, growing downward.
2342 // We need to adjust it to work correctly with guard_memory()
2343 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2344 address base = stack_red_zone_base() - stack_red_zone_size();
2345
2346 guarantee(base < stack_base(),"Error calculating stack red zone");
2347 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2348
2349 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2350 warning("Attempt to guard stack red zone failed.");
2351 }
2352 }
2353
2354 void JavaThread::disable_stack_red_zone() {
2355 // The base notation is from the stacks point of view, growing downward.
2356 // We need to adjust it to work correctly with guard_memory()
2357 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2358 address base = stack_red_zone_base() - stack_red_zone_size();
2359 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2360 warning("Attempt to unguard stack red zone failed.");
2361 }
2362 }
2363
2364 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2365 // ignore is there is no stack
2366 if (!has_last_Java_frame()) return;
2367 // traverse the stack frames. Starts from top frame.
2368 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2369 frame* fr = fst.current();
2370 f(fr, fst.register_map());
2371 }
2372 }
2373
2374
2375 #ifndef PRODUCT
2376 // Deoptimization
2377 // Function for testing deoptimization
2378 void JavaThread::deoptimize() {
2379 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2380 StackFrameStream fst(this, UseBiasedLocking);
2381 bool deopt = false; // Dump stack only if a deopt actually happens.
2382 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2383 // Iterate over all frames in the thread and deoptimize
2384 for(; !fst.is_done(); fst.next()) {
2385 if(fst.current()->can_be_deoptimized()) {
2386
2387 if (only_at) {
2388 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2389 // consists of comma or carriage return separated numbers so
2390 // search for the current bci in that string.
2391 address pc = fst.current()->pc();
2392 nmethod* nm = (nmethod*) fst.current()->cb();
2393 ScopeDesc* sd = nm->scope_desc_at( pc);
2394 char buffer[8];
2395 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2396 size_t len = strlen(buffer);
2397 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2398 while (found != NULL) {
2399 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2400 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2401 // Check that the bci found is bracketed by terminators.
2402 break;
2403 }
2404 found = strstr(found + 1, buffer);
2405 }
2406 if (!found) {
2407 continue;
2408 }
2409 }
2410
2411 if (DebugDeoptimization && !deopt) {
2412 deopt = true; // One-time only print before deopt
2413 tty->print_cr("[BEFORE Deoptimization]");
2414 trace_frames();
2415 trace_stack();
2416 }
2417 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2418 }
2419 }
2420
2421 if (DebugDeoptimization && deopt) {
2422 tty->print_cr("[AFTER Deoptimization]");
2423 trace_frames();
2424 }
2425 }
2426
2427
2428 // Make zombies
2429 void JavaThread::make_zombies() {
2430 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2431 if (fst.current()->can_be_deoptimized()) {
2432 // it is a Java nmethod
2433 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2434 nm->make_not_entrant();
2435 }
2436 }
2437 }
2438 #endif // PRODUCT
2439
2440
2441 void JavaThread::deoptimized_wrt_marked_nmethods() {
2442 if (!has_last_Java_frame()) return;
2443 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2444 StackFrameStream fst(this, UseBiasedLocking);
2445 for(; !fst.is_done(); fst.next()) {
2446 if (fst.current()->should_be_deoptimized()) {
2447 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2448 }
2449 }
2450 }
2451
2452
2453 // GC support
2454 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2455
2456 void JavaThread::gc_epilogue() {
2457 frames_do(frame_gc_epilogue);
2458 }
2459
2460
2461 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2462
2463 void JavaThread::gc_prologue() {
2464 frames_do(frame_gc_prologue);
2465 }
2466
2467 // If the caller is a NamedThread, then remember, in the current scope,
2468 // the given JavaThread in its _processed_thread field.
2469 class RememberProcessedThread: public StackObj {
2470 NamedThread* _cur_thr;
2471 public:
2472 RememberProcessedThread(JavaThread* jthr) {
2473 Thread* thread = Thread::current();
2474 if (thread->is_Named_thread()) {
2475 _cur_thr = (NamedThread *)thread;
2476 _cur_thr->set_processed_thread(jthr);
2477 } else {
2478 _cur_thr = NULL;
2479 }
2480 }
2481
2482 ~RememberProcessedThread() {
2483 if (_cur_thr) {
2484 _cur_thr->set_processed_thread(NULL);
2485 }
2486 }
2487 };
2488
2489 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2490 // Verify that the deferred card marks have been flushed.
2491 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2492
2493 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2494 // since there may be more than one thread using each ThreadProfiler.
2495
2496 // Traverse the GCHandles
2497 Thread::oops_do(f, cf);
2498
2499 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2500 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2501
2502 if (has_last_Java_frame()) {
2503 // Record JavaThread to GC thread
2504 RememberProcessedThread rpt(this);
2505
2506 // Traverse the privileged stack
2507 if (_privileged_stack_top != NULL) {
2508 _privileged_stack_top->oops_do(f);
2509 }
2510
2511 // traverse the registered growable array
2512 if (_array_for_gc != NULL) {
2513 for (int index = 0; index < _array_for_gc->length(); index++) {
2514 f->do_oop(_array_for_gc->adr_at(index));
2515 }
2516 }
2517
2518 // Traverse the monitor chunks
2519 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2520 chunk->oops_do(f);
2521 }
2522
2523 // Traverse the execution stack
2524 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2525 fst.current()->oops_do(f, cf, fst.register_map());
2526 }
2527 }
2528
2529 // callee_target is never live across a gc point so NULL it here should
2530 // it still contain a methdOop.
2531
2532 set_callee_target(NULL);
2533
2534 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2535 // If we have deferred set_locals there might be oops waiting to be
2536 // written
2537 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2538 if (list != NULL) {
2539 for (int i = 0; i < list->length(); i++) {
2540 list->at(i)->oops_do(f);
2541 }
2542 }
2543
2544 // Traverse instance variables at the end since the GC may be moving things
2545 // around using this function
2546 f->do_oop((oop*) &_threadObj);
2547 f->do_oop((oop*) &_vm_result);
2548 f->do_oop((oop*) &_vm_result_2);
2549 f->do_oop((oop*) &_exception_oop);
2550 f->do_oop((oop*) &_pending_async_exception);
2551
2552 if (jvmti_thread_state() != NULL) {
2553 jvmti_thread_state()->oops_do(f);
2554 }
2555 }
2556
2557 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2558 Thread::nmethods_do(cf); // (super method is a no-op)
2559
2560 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2561 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2562
2563 if (has_last_Java_frame()) {
2564 // Traverse the execution stack
2565 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2566 fst.current()->nmethods_do(cf);
2567 }
2568 }
2569 }
2570
2571 // Printing
2572 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2573 switch (_thread_state) {
2574 case _thread_uninitialized: return "_thread_uninitialized";
2575 case _thread_new: return "_thread_new";
2576 case _thread_new_trans: return "_thread_new_trans";
2577 case _thread_in_native: return "_thread_in_native";
2578 case _thread_in_native_trans: return "_thread_in_native_trans";
2579 case _thread_in_vm: return "_thread_in_vm";
2580 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2581 case _thread_in_Java: return "_thread_in_Java";
2582 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2583 case _thread_blocked: return "_thread_blocked";
2584 case _thread_blocked_trans: return "_thread_blocked_trans";
2585 default: return "unknown thread state";
2586 }
2587 }
2588
2589 #ifndef PRODUCT
2590 void JavaThread::print_thread_state_on(outputStream *st) const {
2591 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2592 };
2593 void JavaThread::print_thread_state() const {
2594 print_thread_state_on(tty);
2595 };
2596 #endif // PRODUCT
2597
2598 // Called by Threads::print() for VM_PrintThreads operation
2599 void JavaThread::print_on(outputStream *st) const {
2600 st->print("\"%s\" ", get_thread_name());
2601 oop thread_oop = threadObj();
2602 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2603 Thread::print_on(st);
2604 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2605 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2606 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2607 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2608 }
2609 #ifndef PRODUCT
2610 print_thread_state_on(st);
2611 _safepoint_state->print_on(st);
2612 #endif // PRODUCT
2613 }
2614
2615 // Called by fatal error handler. The difference between this and
2616 // JavaThread::print() is that we can't grab lock or allocate memory.
2617 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2618 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2619 oop thread_obj = threadObj();
2620 if (thread_obj != NULL) {
2621 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2622 }
2623 st->print(" [");
2624 st->print("%s", _get_thread_state_name(_thread_state));
2625 if (osthread()) {
2626 st->print(", id=%d", osthread()->thread_id());
2627 }
2628 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2629 _stack_base - _stack_size, _stack_base);
2630 st->print("]");
2631 return;
2632 }
2633
2634 // Verification
2635
2636 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2637
2638 void JavaThread::verify() {
2639 // Verify oops in the thread.
2640 oops_do(&VerifyOopClosure::verify_oop, NULL);
2641
2642 // Verify the stack frames.
2643 frames_do(frame_verify);
2644 }
2645
2646 // CR 6300358 (sub-CR 2137150)
2647 // Most callers of this method assume that it can't return NULL but a
2648 // thread may not have a name whilst it is in the process of attaching to
2649 // the VM - see CR 6412693, and there are places where a JavaThread can be
2650 // seen prior to having it's threadObj set (eg JNI attaching threads and
2651 // if vm exit occurs during initialization). These cases can all be accounted
2652 // for such that this method never returns NULL.
2653 const char* JavaThread::get_thread_name() const {
2654 #ifdef ASSERT
2655 // early safepoints can hit while current thread does not yet have TLS
2656 if (!SafepointSynchronize::is_at_safepoint()) {
2657 Thread *cur = Thread::current();
2658 if (!(cur->is_Java_thread() && cur == this)) {
2659 // Current JavaThreads are allowed to get their own name without
2660 // the Threads_lock.
2661 assert_locked_or_safepoint(Threads_lock);
2662 }
2663 }
2664 #endif // ASSERT
2665 return get_thread_name_string();
2666 }
2667
2668 // Returns a non-NULL representation of this thread's name, or a suitable
2669 // descriptive string if there is no set name
2670 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2671 const char* name_str;
2672 oop thread_obj = threadObj();
2673 if (thread_obj != NULL) {
2674 typeArrayOop name = java_lang_Thread::name(thread_obj);
2675 if (name != NULL) {
2676 if (buf == NULL) {
2677 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2678 }
2679 else {
2680 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2681 }
2682 }
2683 else if (is_attaching()) { // workaround for 6412693 - see 6404306
2684 name_str = "<no-name - thread is attaching>";
2685 }
2686 else {
2687 name_str = Thread::name();
2688 }
2689 }
2690 else {
2691 name_str = Thread::name();
2692 }
2693 assert(name_str != NULL, "unexpected NULL thread name");
2694 return name_str;
2695 }
2696
2697
2698 const char* JavaThread::get_threadgroup_name() const {
2699 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2700 oop thread_obj = threadObj();
2701 if (thread_obj != NULL) {
2702 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2703 if (thread_group != NULL) {
2704 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2705 // ThreadGroup.name can be null
2706 if (name != NULL) {
2707 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2708 return str;
2709 }
2710 }
2711 }
2712 return NULL;
2713 }
2714
2715 const char* JavaThread::get_parent_name() const {
2716 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2717 oop thread_obj = threadObj();
2718 if (thread_obj != NULL) {
2719 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2720 if (thread_group != NULL) {
2721 oop parent = java_lang_ThreadGroup::parent(thread_group);
2722 if (parent != NULL) {
2723 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2724 // ThreadGroup.name can be null
2725 if (name != NULL) {
2726 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2727 return str;
2728 }
2729 }
2730 }
2731 }
2732 return NULL;
2733 }
2734
2735 ThreadPriority JavaThread::java_priority() const {
2736 oop thr_oop = threadObj();
2737 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2738 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2739 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2740 return priority;
2741 }
2742
2743 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2744
2745 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2746 // Link Java Thread object <-> C++ Thread
2747
2748 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2749 // and put it into a new Handle. The Handle "thread_oop" can then
2750 // be used to pass the C++ thread object to other methods.
2751
2752 // Set the Java level thread object (jthread) field of the
2753 // new thread (a JavaThread *) to C++ thread object using the
2754 // "thread_oop" handle.
2755
2756 // Set the thread field (a JavaThread *) of the
2757 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2758
2759 Handle thread_oop(Thread::current(),
2760 JNIHandles::resolve_non_null(jni_thread));
2761 assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
2762 "must be initialized");
2763 set_threadObj(thread_oop());
2764 java_lang_Thread::set_thread(thread_oop(), this);
2765
2766 if (prio == NoPriority) {
2767 prio = java_lang_Thread::priority(thread_oop());
2768 assert(prio != NoPriority, "A valid priority should be present");
2769 }
2770
2771 // Push the Java priority down to the native thread; needs Threads_lock
2772 Thread::set_priority(this, prio);
2773
2774 // Add the new thread to the Threads list and set it in motion.
2775 // We must have threads lock in order to call Threads::add.
2776 // It is crucial that we do not block before the thread is
2777 // added to the Threads list for if a GC happens, then the java_thread oop
2778 // will not be visited by GC.
2779 Threads::add(this);
2780 }
2781
2782 oop JavaThread::current_park_blocker() {
2783 // Support for JSR-166 locks
2784 oop thread_oop = threadObj();
2785 if (thread_oop != NULL &&
2786 JDK_Version::current().supports_thread_park_blocker()) {
2787 return java_lang_Thread::park_blocker(thread_oop);
2788 }
2789 return NULL;
2790 }
2791
2792
2793 void JavaThread::print_stack_on(outputStream* st) {
2794 if (!has_last_Java_frame()) return;
2795 ResourceMark rm;
2796 HandleMark hm;
2797
2798 RegisterMap reg_map(this);
2799 vframe* start_vf = last_java_vframe(®_map);
2800 int count = 0;
2801 for (vframe* f = start_vf; f; f = f->sender() ) {
2802 if (f->is_java_frame()) {
2803 javaVFrame* jvf = javaVFrame::cast(f);
2804 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2805
2806 // Print out lock information
2807 if (JavaMonitorsInStackTrace) {
2808 jvf->print_lock_info_on(st, count);
2809 }
2810 } else {
2811 // Ignore non-Java frames
2812 }
2813
2814 // Bail-out case for too deep stacks
2815 count++;
2816 if (MaxJavaStackTraceDepth == count) return;
2817 }
2818 }
2819
2820
2821 // JVMTI PopFrame support
2822 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2823 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2824 if (in_bytes(size_in_bytes) != 0) {
2825 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes));
2826 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2827 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2828 }
2829 }
2830
2831 void* JavaThread::popframe_preserved_args() {
2832 return _popframe_preserved_args;
2833 }
2834
2835 ByteSize JavaThread::popframe_preserved_args_size() {
2836 return in_ByteSize(_popframe_preserved_args_size);
2837 }
2838
2839 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2840 int sz = in_bytes(popframe_preserved_args_size());
2841 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2842 return in_WordSize(sz / wordSize);
2843 }
2844
2845 void JavaThread::popframe_free_preserved_args() {
2846 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2847 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
2848 _popframe_preserved_args = NULL;
2849 _popframe_preserved_args_size = 0;
2850 }
2851
2852 #ifndef PRODUCT
2853
2854 void JavaThread::trace_frames() {
2855 tty->print_cr("[Describe stack]");
2856 int frame_no = 1;
2857 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2858 tty->print(" %d. ", frame_no++);
2859 fst.current()->print_value_on(tty,this);
2860 tty->cr();
2861 }
2862 }
2863
2864
2865 #ifdef ASSERT
2866 // Print or validate the layout of stack frames
2867 void JavaThread::print_frame_layout(int depth, bool validate_only) {
2868 ResourceMark rm;
2869 PRESERVE_EXCEPTION_MARK;
2870 FrameValues values;
2871 int frame_no = 0;
2872 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
2873 fst.current()->describe(values, ++frame_no);
2874 if (depth == frame_no) break;
2875 }
2876 if (validate_only) {
2877 values.validate();
2878 } else {
2879 tty->print_cr("[Describe stack layout]");
2880 values.print();
2881 }
2882 }
2883 #endif
2884
2885 void JavaThread::trace_stack_from(vframe* start_vf) {
2886 ResourceMark rm;
2887 int vframe_no = 1;
2888 for (vframe* f = start_vf; f; f = f->sender() ) {
2889 if (f->is_java_frame()) {
2890 javaVFrame::cast(f)->print_activation(vframe_no++);
2891 } else {
2892 f->print();
2893 }
2894 if (vframe_no > StackPrintLimit) {
2895 tty->print_cr("...<more frames>...");
2896 return;
2897 }
2898 }
2899 }
2900
2901
2902 void JavaThread::trace_stack() {
2903 if (!has_last_Java_frame()) return;
2904 ResourceMark rm;
2905 HandleMark hm;
2906 RegisterMap reg_map(this);
2907 trace_stack_from(last_java_vframe(®_map));
2908 }
2909
2910
2911 #endif // PRODUCT
2912
2913
2914 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2915 assert(reg_map != NULL, "a map must be given");
2916 frame f = last_frame();
2917 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
2918 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2919 }
2920 return NULL;
2921 }
2922
2923
2924 klassOop JavaThread::security_get_caller_class(int depth) {
2925 vframeStream vfst(this);
2926 vfst.security_get_caller_frame(depth);
2927 if (!vfst.at_end()) {
2928 return vfst.method()->method_holder();
2929 }
2930 return NULL;
2931 }
2932
2933 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
2934 assert(thread->is_Compiler_thread(), "must be compiler thread");
2935 CompileBroker::compiler_thread_loop();
2936 }
2937
2938 // Create a CompilerThread
2939 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
2940 : JavaThread(&compiler_thread_entry) {
2941 _env = NULL;
2942 _log = NULL;
2943 _task = NULL;
2944 _queue = queue;
2945 _counters = counters;
2946 _buffer_blob = NULL;
2947 _scanned_nmethod = NULL;
2948
2949 #ifndef PRODUCT
2950 _ideal_graph_printer = NULL;
2951 #endif
2952 }
2953
2954 void CompilerThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2955 JavaThread::oops_do(f, cf);
2956 if (_scanned_nmethod != NULL && cf != NULL) {
2957 // Safepoints can occur when the sweeper is scanning an nmethod so
2958 // process it here to make sure it isn't unloaded in the middle of
2959 // a scan.
2960 cf->do_code_blob(_scanned_nmethod);
2961 }
2962 }
2963
2964 // ======= Threads ========
2965
2966 // The Threads class links together all active threads, and provides
2967 // operations over all threads. It is protected by its own Mutex
2968 // lock, which is also used in other contexts to protect thread
2969 // operations from having the thread being operated on from exiting
2970 // and going away unexpectedly (e.g., safepoint synchronization)
2971
2972 JavaThread* Threads::_thread_list = NULL;
2973 int Threads::_number_of_threads = 0;
2974 int Threads::_number_of_non_daemon_threads = 0;
2975 int Threads::_return_code = 0;
2976 size_t JavaThread::_stack_size_at_create = 0;
2977
2978 // All JavaThreads
2979 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
2980
2981 void os_stream();
2982
2983 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
2984 void Threads::threads_do(ThreadClosure* tc) {
2985 assert_locked_or_safepoint(Threads_lock);
2986 // ALL_JAVA_THREADS iterates through all JavaThreads
2987 ALL_JAVA_THREADS(p) {
2988 tc->do_thread(p);
2989 }
2990 // Someday we could have a table or list of all non-JavaThreads.
2991 // For now, just manually iterate through them.
2992 tc->do_thread(VMThread::vm_thread());
2993 Universe::heap()->gc_threads_do(tc);
2994 WatcherThread *wt = WatcherThread::watcher_thread();
2995 // Strictly speaking, the following NULL check isn't sufficient to make sure
2996 // the data for WatcherThread is still valid upon being examined. However,
2997 // considering that WatchThread terminates when the VM is on the way to
2998 // exit at safepoint, the chance of the above is extremely small. The right
2999 // way to prevent termination of WatcherThread would be to acquire
3000 // Terminator_lock, but we can't do that without violating the lock rank
3001 // checking in some cases.
3002 if (wt != NULL)
3003 tc->do_thread(wt);
3004
3005 // If CompilerThreads ever become non-JavaThreads, add them here
3006 }
3007
3008 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3009
3010 extern void JDK_Version_init();
3011
3012 // Check version
3013 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3014
3015 // Initialize the output stream module
3016 ostream_init();
3017
3018 // Process java launcher properties.
3019 Arguments::process_sun_java_launcher_properties(args);
3020
3021 // Initialize the os module before using TLS
3022 os::init();
3023
3024 // Initialize system properties.
3025 Arguments::init_system_properties();
3026
3027 // So that JDK version can be used as a discrimintor when parsing arguments
3028 JDK_Version_init();
3029
3030 // Update/Initialize System properties after JDK version number is known
3031 Arguments::init_version_specific_system_properties();
3032
3033 // Parse arguments
3034 jint parse_result = Arguments::parse(args);
3035 if (parse_result != JNI_OK) return parse_result;
3036
3037 if (PauseAtStartup) {
3038 os::pause();
3039 }
3040
3041 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3042
3043 // Record VM creation timing statistics
3044 TraceVmCreationTime create_vm_timer;
3045 create_vm_timer.start();
3046
3047 // Timing (must come after argument parsing)
3048 TraceTime timer("Create VM", TraceStartupTime);
3049
3050 // Initialize the os module after parsing the args
3051 jint os_init_2_result = os::init_2();
3052 if (os_init_2_result != JNI_OK) return os_init_2_result;
3053
3054 // Initialize output stream logging
3055 ostream_init_log();
3056
3057 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3058 // Must be before create_vm_init_agents()
3059 if (Arguments::init_libraries_at_startup()) {
3060 convert_vm_init_libraries_to_agents();
3061 }
3062
3063 // Launch -agentlib/-agentpath and converted -Xrun agents
3064 if (Arguments::init_agents_at_startup()) {
3065 create_vm_init_agents();
3066 }
3067
3068 // Initialize Threads state
3069 _thread_list = NULL;
3070 _number_of_threads = 0;
3071 _number_of_non_daemon_threads = 0;
3072
3073 // Initialize TLS
3074 ThreadLocalStorage::init();
3075
3076 // Initialize global data structures and create system classes in heap
3077 vm_init_globals();
3078
3079 // Attach the main thread to this os thread
3080 JavaThread* main_thread = new JavaThread();
3081 main_thread->set_thread_state(_thread_in_vm);
3082 // must do this before set_active_handles and initialize_thread_local_storage
3083 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3084 // change the stack size recorded here to one based on the java thread
3085 // stacksize. This adjusted size is what is used to figure the placement
3086 // of the guard pages.
3087 main_thread->record_stack_base_and_size();
3088 main_thread->initialize_thread_local_storage();
3089
3090 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3091
3092 if (!main_thread->set_as_starting_thread()) {
3093 vm_shutdown_during_initialization(
3094 "Failed necessary internal allocation. Out of swap space");
3095 delete main_thread;
3096 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3097 return JNI_ENOMEM;
3098 }
3099
3100 // Enable guard page *after* os::create_main_thread(), otherwise it would
3101 // crash Linux VM, see notes in os_linux.cpp.
3102 main_thread->create_stack_guard_pages();
3103
3104 // Initialize Java-Level synchronization subsystem
3105 ObjectMonitor::Initialize() ;
3106
3107 // Initialize global modules
3108 jint status = init_globals();
3109 if (status != JNI_OK) {
3110 delete main_thread;
3111 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3112 return status;
3113 }
3114
3115 // Should be done after the heap is fully created
3116 main_thread->cache_global_variables();
3117
3118 HandleMark hm;
3119
3120 { MutexLocker mu(Threads_lock);
3121 Threads::add(main_thread);
3122 }
3123
3124 // Any JVMTI raw monitors entered in onload will transition into
3125 // real raw monitor. VM is setup enough here for raw monitor enter.
3126 JvmtiExport::transition_pending_onload_raw_monitors();
3127
3128 if (VerifyBeforeGC &&
3129 Universe::heap()->total_collections() >= VerifyGCStartAt) {
3130 Universe::heap()->prepare_for_verify();
3131 Universe::verify(); // make sure we're starting with a clean slate
3132 }
3133
3134 // Create the VMThread
3135 { TraceTime timer("Start VMThread", TraceStartupTime);
3136 VMThread::create();
3137 Thread* vmthread = VMThread::vm_thread();
3138
3139 if (!os::create_thread(vmthread, os::vm_thread))
3140 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3141
3142 // Wait for the VM thread to become ready, and VMThread::run to initialize
3143 // Monitors can have spurious returns, must always check another state flag
3144 {
3145 MutexLocker ml(Notify_lock);
3146 os::start_thread(vmthread);
3147 while (vmthread->active_handles() == NULL) {
3148 Notify_lock->wait();
3149 }
3150 }
3151 }
3152
3153 assert (Universe::is_fully_initialized(), "not initialized");
3154 EXCEPTION_MARK;
3155
3156 // At this point, the Universe is initialized, but we have not executed
3157 // any byte code. Now is a good time (the only time) to dump out the
3158 // internal state of the JVM for sharing.
3159
3160 if (DumpSharedSpaces) {
3161 Universe::heap()->preload_and_dump(CHECK_0);
3162 ShouldNotReachHere();
3163 }
3164
3165 // Always call even when there are not JVMTI environments yet, since environments
3166 // may be attached late and JVMTI must track phases of VM execution
3167 JvmtiExport::enter_start_phase();
3168
3169 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3170 JvmtiExport::post_vm_start();
3171
3172 {
3173 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3174
3175 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3176 create_vm_init_libraries();
3177 }
3178
3179 if (InitializeJavaLangString) {
3180 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3181 } else {
3182 warning("java.lang.String not initialized");
3183 }
3184
3185 if (AggressiveOpts) {
3186 {
3187 // Forcibly initialize java/util/HashMap and mutate the private
3188 // static final "frontCacheEnabled" field before we start creating instances
3189 #ifdef ASSERT
3190 klassOop tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3191 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
3192 #endif
3193 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3194 KlassHandle k = KlassHandle(THREAD, k_o);
3195 guarantee(k.not_null(), "Must find java/util/HashMap");
3196 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3197 ik->initialize(CHECK_0);
3198 fieldDescriptor fd;
3199 // Possible we might not find this field; if so, don't break
3200 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3201 k()->java_mirror()->bool_field_put(fd.offset(), true);
3202 }
3203 }
3204
3205 if (UseStringCache) {
3206 // Forcibly initialize java/lang/StringValue and mutate the private
3207 // static final "stringCacheEnabled" field before we start creating instances
3208 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3209 // Possible that StringValue isn't present: if so, silently don't break
3210 if (k_o != NULL) {
3211 KlassHandle k = KlassHandle(THREAD, k_o);
3212 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3213 ik->initialize(CHECK_0);
3214 fieldDescriptor fd;
3215 // Possible we might not find this field: if so, silently don't break
3216 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3217 k()->java_mirror()->bool_field_put(fd.offset(), true);
3218 }
3219 }
3220 }
3221 }
3222
3223 // Initialize java_lang.System (needed before creating the thread)
3224 if (InitializeJavaLangSystem) {
3225 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3226 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3227 Handle thread_group = create_initial_thread_group(CHECK_0);
3228 Universe::set_main_thread_group(thread_group());
3229 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3230 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3231 main_thread->set_threadObj(thread_object);
3232 // Set thread status to running since main thread has
3233 // been started and running.
3234 java_lang_Thread::set_thread_status(thread_object,
3235 java_lang_Thread::RUNNABLE);
3236
3237 // The VM preresolve methods to these classes. Make sure that get initialized
3238 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3239 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3240 // The VM creates & returns objects of this class. Make sure it's initialized.
3241 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3242 call_initializeSystemClass(CHECK_0);
3243 } else {
3244 warning("java.lang.System not initialized");
3245 }
3246
3247 // an instance of OutOfMemory exception has been allocated earlier
3248 if (InitializeJavaLangExceptionsErrors) {
3249 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3250 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3251 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3252 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3253 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3254 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3255 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3256 } else {
3257 warning("java.lang.OutOfMemoryError has not been initialized");
3258 warning("java.lang.NullPointerException has not been initialized");
3259 warning("java.lang.ClassCastException has not been initialized");
3260 warning("java.lang.ArrayStoreException has not been initialized");
3261 warning("java.lang.ArithmeticException has not been initialized");
3262 warning("java.lang.StackOverflowError has not been initialized");
3263 }
3264 }
3265
3266 // See : bugid 4211085.
3267 // Background : the static initializer of java.lang.Compiler tries to read
3268 // property"java.compiler" and read & write property "java.vm.info".
3269 // When a security manager is installed through the command line
3270 // option "-Djava.security.manager", the above properties are not
3271 // readable and the static initializer for java.lang.Compiler fails
3272 // resulting in a NoClassDefFoundError. This can happen in any
3273 // user code which calls methods in java.lang.Compiler.
3274 // Hack : the hack is to pre-load and initialize this class, so that only
3275 // system domains are on the stack when the properties are read.
3276 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3277 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3278 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3279 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3280 // Once that is done, we should remove this hack.
3281 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3282
3283 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3284 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3285 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3286 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3287 // This should also be taken out as soon as 4211383 gets fixed.
3288 reset_vm_info_property(CHECK_0);
3289
3290 quicken_jni_functions();
3291
3292 // Set flag that basic initialization has completed. Used by exceptions and various
3293 // debug stuff, that does not work until all basic classes have been initialized.
3294 set_init_completed();
3295
3296 HS_DTRACE_PROBE(hotspot, vm__init__end);
3297
3298 // record VM initialization completion time
3299 Management::record_vm_init_completed();
3300
3301 // Compute system loader. Note that this has to occur after set_init_completed, since
3302 // valid exceptions may be thrown in the process.
3303 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3304 // set_init_completed has just been called, causing exceptions not to be shortcut
3305 // anymore. We call vm_exit_during_initialization directly instead.
3306 SystemDictionary::compute_java_system_loader(THREAD);
3307 if (HAS_PENDING_EXCEPTION) {
3308 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3309 }
3310
3311 #ifndef SERIALGC
3312 // Support for ConcurrentMarkSweep. This should be cleaned up
3313 // and better encapsulated. The ugly nested if test would go away
3314 // once things are properly refactored. XXX YSR
3315 if (UseConcMarkSweepGC || UseG1GC) {
3316 if (UseConcMarkSweepGC) {
3317 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3318 } else {
3319 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3320 }
3321 if (HAS_PENDING_EXCEPTION) {
3322 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3323 }
3324 }
3325 #endif // SERIALGC
3326
3327 // Always call even when there are not JVMTI environments yet, since environments
3328 // may be attached late and JVMTI must track phases of VM execution
3329 JvmtiExport::enter_live_phase();
3330
3331 // Signal Dispatcher needs to be started before VMInit event is posted
3332 os::signal_init();
3333
3334 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3335 if (!DisableAttachMechanism) {
3336 if (StartAttachListener || AttachListener::init_at_startup()) {
3337 AttachListener::init();
3338 }
3339 }
3340
3341 // Launch -Xrun agents
3342 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3343 // back-end can launch with -Xdebug -Xrunjdwp.
3344 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3345 create_vm_init_libraries();
3346 }
3347
3348 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3349 JvmtiExport::post_vm_initialized();
3350
3351 Chunk::start_chunk_pool_cleaner_task();
3352
3353 // initialize compiler(s)
3354 CompileBroker::compilation_init();
3355
3356 Management::initialize(THREAD);
3357 if (HAS_PENDING_EXCEPTION) {
3358 // management agent fails to start possibly due to
3359 // configuration problem and is responsible for printing
3360 // stack trace if appropriate. Simply exit VM.
3361 vm_exit(1);
3362 }
3363
3364 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3365 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3366 if (MemProfiling) MemProfiler::engage();
3367 StatSampler::engage();
3368 if (CheckJNICalls) JniPeriodicChecker::engage();
3369
3370 BiasedLocking::init();
3371
3372 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3373 call_postVMInitHook(THREAD);
3374 // The Java side of PostVMInitHook.run must deal with all
3375 // exceptions and provide means of diagnosis.
3376 if (HAS_PENDING_EXCEPTION) {
3377 CLEAR_PENDING_EXCEPTION;
3378 }
3379 }
3380
3381 // Start up the WatcherThread if there are any periodic tasks
3382 // NOTE: All PeriodicTasks should be registered by now. If they
3383 // aren't, late joiners might appear to start slowly (we might
3384 // take a while to process their first tick).
3385 if (PeriodicTask::num_tasks() > 0) {
3386 WatcherThread::start();
3387 }
3388
3389 // Give os specific code one last chance to start
3390 os::init_3();
3391
3392 create_vm_timer.end();
3393 return JNI_OK;
3394 }
3395
3396 // type for the Agent_OnLoad and JVM_OnLoad entry points
3397 extern "C" {
3398 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3399 }
3400 // Find a command line agent library and return its entry point for
3401 // -agentlib: -agentpath: -Xrun
3402 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3403 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3404 OnLoadEntry_t on_load_entry = NULL;
3405 void *library = agent->os_lib(); // check if we have looked it up before
3406
3407 if (library == NULL) {
3408 char buffer[JVM_MAXPATHLEN];
3409 char ebuf[1024];
3410 const char *name = agent->name();
3411 const char *msg = "Could not find agent library ";
3412
3413 if (agent->is_absolute_path()) {
3414 library = os::dll_load(name, ebuf, sizeof ebuf);
3415 if (library == NULL) {
3416 const char *sub_msg = " in absolute path, with error: ";
3417 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3418 char *buf = NEW_C_HEAP_ARRAY(char, len);
3419 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3420 // If we can't find the agent, exit.
3421 vm_exit_during_initialization(buf, NULL);
3422 FREE_C_HEAP_ARRAY(char, buf);
3423 }
3424 } else {
3425 // Try to load the agent from the standard dll directory
3426 os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
3427 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3428 #ifdef KERNEL
3429 // Download instrument dll
3430 if (library == NULL && strcmp(name, "instrument") == 0) {
3431 char *props = Arguments::get_kernel_properties();
3432 char *home = Arguments::get_java_home();
3433 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false"
3434 " sun.jkernel.DownloadManager -download client_jvm";
3435 size_t length = strlen(props) + strlen(home) + strlen(fmt) + 1;
3436 char *cmd = NEW_C_HEAP_ARRAY(char, length);
3437 jio_snprintf(cmd, length, fmt, home, props);
3438 int status = os::fork_and_exec(cmd);
3439 FreeHeap(props);
3440 if (status == -1) {
3441 warning(cmd);
3442 vm_exit_during_initialization("fork_and_exec failed: %s",
3443 strerror(errno));
3444 }
3445 FREE_C_HEAP_ARRAY(char, cmd);
3446 // when this comes back the instrument.dll should be where it belongs.
3447 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3448 }
3449 #endif // KERNEL
3450 if (library == NULL) { // Try the local directory
3451 char ns[1] = {0};
3452 os::dll_build_name(buffer, sizeof(buffer), ns, name);
3453 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3454 if (library == NULL) {
3455 const char *sub_msg = " on the library path, with error: ";
3456 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3457 char *buf = NEW_C_HEAP_ARRAY(char, len);
3458 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3459 // If we can't find the agent, exit.
3460 vm_exit_during_initialization(buf, NULL);
3461 FREE_C_HEAP_ARRAY(char, buf);
3462 }
3463 }
3464 }
3465 agent->set_os_lib(library);
3466 }
3467
3468 // Find the OnLoad function.
3469 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3470 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index]));
3471 if (on_load_entry != NULL) break;
3472 }
3473 return on_load_entry;
3474 }
3475
3476 // Find the JVM_OnLoad entry point
3477 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3478 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3479 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3480 }
3481
3482 // Find the Agent_OnLoad entry point
3483 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3484 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3485 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3486 }
3487
3488 // For backwards compatibility with -Xrun
3489 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3490 // treated like -agentpath:
3491 // Must be called before agent libraries are created
3492 void Threads::convert_vm_init_libraries_to_agents() {
3493 AgentLibrary* agent;
3494 AgentLibrary* next;
3495
3496 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3497 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3498 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3499
3500 // If there is an JVM_OnLoad function it will get called later,
3501 // otherwise see if there is an Agent_OnLoad
3502 if (on_load_entry == NULL) {
3503 on_load_entry = lookup_agent_on_load(agent);
3504 if (on_load_entry != NULL) {
3505 // switch it to the agent list -- so that Agent_OnLoad will be called,
3506 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3507 Arguments::convert_library_to_agent(agent);
3508 } else {
3509 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3510 }
3511 }
3512 }
3513 }
3514
3515 // Create agents for -agentlib: -agentpath: and converted -Xrun
3516 // Invokes Agent_OnLoad
3517 // Called very early -- before JavaThreads exist
3518 void Threads::create_vm_init_agents() {
3519 extern struct JavaVM_ main_vm;
3520 AgentLibrary* agent;
3521
3522 JvmtiExport::enter_onload_phase();
3523 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3524 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3525
3526 if (on_load_entry != NULL) {
3527 // Invoke the Agent_OnLoad function
3528 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3529 if (err != JNI_OK) {
3530 vm_exit_during_initialization("agent library failed to init", agent->name());
3531 }
3532 } else {
3533 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3534 }
3535 }
3536 JvmtiExport::enter_primordial_phase();
3537 }
3538
3539 extern "C" {
3540 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3541 }
3542
3543 void Threads::shutdown_vm_agents() {
3544 // Send any Agent_OnUnload notifications
3545 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3546 extern struct JavaVM_ main_vm;
3547 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3548
3549 // Find the Agent_OnUnload function.
3550 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3551 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3552 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3553
3554 // Invoke the Agent_OnUnload function
3555 if (unload_entry != NULL) {
3556 JavaThread* thread = JavaThread::current();
3557 ThreadToNativeFromVM ttn(thread);
3558 HandleMark hm(thread);
3559 (*unload_entry)(&main_vm);
3560 break;
3561 }
3562 }
3563 }
3564 }
3565
3566 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3567 // Invokes JVM_OnLoad
3568 void Threads::create_vm_init_libraries() {
3569 extern struct JavaVM_ main_vm;
3570 AgentLibrary* agent;
3571
3572 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3573 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3574
3575 if (on_load_entry != NULL) {
3576 // Invoke the JVM_OnLoad function
3577 JavaThread* thread = JavaThread::current();
3578 ThreadToNativeFromVM ttn(thread);
3579 HandleMark hm(thread);
3580 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3581 if (err != JNI_OK) {
3582 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3583 }
3584 } else {
3585 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3586 }
3587 }
3588 }
3589
3590 // Last thread running calls java.lang.Shutdown.shutdown()
3591 void JavaThread::invoke_shutdown_hooks() {
3592 HandleMark hm(this);
3593
3594 // We could get here with a pending exception, if so clear it now.
3595 if (this->has_pending_exception()) {
3596 this->clear_pending_exception();
3597 }
3598
3599 EXCEPTION_MARK;
3600 klassOop k =
3601 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3602 THREAD);
3603 if (k != NULL) {
3604 // SystemDictionary::resolve_or_null will return null if there was
3605 // an exception. If we cannot load the Shutdown class, just don't
3606 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3607 // and finalizers (if runFinalizersOnExit is set) won't be run.
3608 // Note that if a shutdown hook was registered or runFinalizersOnExit
3609 // was called, the Shutdown class would have already been loaded
3610 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3611 instanceKlassHandle shutdown_klass (THREAD, k);
3612 JavaValue result(T_VOID);
3613 JavaCalls::call_static(&result,
3614 shutdown_klass,
3615 vmSymbols::shutdown_method_name(),
3616 vmSymbols::void_method_signature(),
3617 THREAD);
3618 }
3619 CLEAR_PENDING_EXCEPTION;
3620 }
3621
3622 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3623 // the program falls off the end of main(). Another VM exit path is through
3624 // vm_exit() when the program calls System.exit() to return a value or when
3625 // there is a serious error in VM. The two shutdown paths are not exactly
3626 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3627 // and VM_Exit op at VM level.
3628 //
3629 // Shutdown sequence:
3630 // + Wait until we are the last non-daemon thread to execute
3631 // <-- every thing is still working at this moment -->
3632 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3633 // shutdown hooks, run finalizers if finalization-on-exit
3634 // + Call before_exit(), prepare for VM exit
3635 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3636 // currently the only user of this mechanism is File.deleteOnExit())
3637 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3638 // post thread end and vm death events to JVMTI,
3639 // stop signal thread
3640 // + Call JavaThread::exit(), it will:
3641 // > release JNI handle blocks, remove stack guard pages
3642 // > remove this thread from Threads list
3643 // <-- no more Java code from this thread after this point -->
3644 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3645 // the compiler threads at safepoint
3646 // <-- do not use anything that could get blocked by Safepoint -->
3647 // + Disable tracing at JNI/JVM barriers
3648 // + Set _vm_exited flag for threads that are still running native code
3649 // + Delete this thread
3650 // + Call exit_globals()
3651 // > deletes tty
3652 // > deletes PerfMemory resources
3653 // + Return to caller
3654
3655 bool Threads::destroy_vm() {
3656 JavaThread* thread = JavaThread::current();
3657
3658 // Wait until we are the last non-daemon thread to execute
3659 { MutexLocker nu(Threads_lock);
3660 while (Threads::number_of_non_daemon_threads() > 1 )
3661 // This wait should make safepoint checks, wait without a timeout,
3662 // and wait as a suspend-equivalent condition.
3663 //
3664 // Note: If the FlatProfiler is running and this thread is waiting
3665 // for another non-daemon thread to finish, then the FlatProfiler
3666 // is waiting for the external suspend request on this thread to
3667 // complete. wait_for_ext_suspend_completion() will eventually
3668 // timeout, but that takes time. Making this wait a suspend-
3669 // equivalent condition solves that timeout problem.
3670 //
3671 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3672 Mutex::_as_suspend_equivalent_flag);
3673 }
3674
3675 // Hang forever on exit if we are reporting an error.
3676 if (ShowMessageBoxOnError && is_error_reported()) {
3677 os::infinite_sleep();
3678 }
3679 os::wait_for_keypress_at_exit();
3680
3681 if (JDK_Version::is_jdk12x_version()) {
3682 // We are the last thread running, so check if finalizers should be run.
3683 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3684 HandleMark rm(thread);
3685 Universe::run_finalizers_on_exit();
3686 } else {
3687 // run Java level shutdown hooks
3688 thread->invoke_shutdown_hooks();
3689 }
3690
3691 before_exit(thread);
3692
3693 thread->exit(true);
3694
3695 // Stop VM thread.
3696 {
3697 // 4945125 The vm thread comes to a safepoint during exit.
3698 // GC vm_operations can get caught at the safepoint, and the
3699 // heap is unparseable if they are caught. Grab the Heap_lock
3700 // to prevent this. The GC vm_operations will not be able to
3701 // queue until after the vm thread is dead.
3702 // After this point, we'll never emerge out of the safepoint before
3703 // the VM exits, so concurrent GC threads do not need to be explicitly
3704 // stopped; they remain inactive until the process exits.
3705 // Note: some concurrent G1 threads may be running during a safepoint,
3706 // but these will not be accessing the heap, just some G1-specific side
3707 // data structures that are not accessed by any other threads but them
3708 // after this point in a terminal safepoint.
3709
3710 MutexLocker ml(Heap_lock);
3711
3712 VMThread::wait_for_vm_thread_exit();
3713 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3714 VMThread::destroy();
3715 }
3716
3717 // clean up ideal graph printers
3718 #if defined(COMPILER2) && !defined(PRODUCT)
3719 IdealGraphPrinter::clean_up();
3720 #endif
3721
3722 // Now, all Java threads are gone except daemon threads. Daemon threads
3723 // running Java code or in VM are stopped by the Safepoint. However,
3724 // daemon threads executing native code are still running. But they
3725 // will be stopped at native=>Java/VM barriers. Note that we can't
3726 // simply kill or suspend them, as it is inherently deadlock-prone.
3727
3728 #ifndef PRODUCT
3729 // disable function tracing at JNI/JVM barriers
3730 TraceJNICalls = false;
3731 TraceJVMCalls = false;
3732 TraceRuntimeCalls = false;
3733 #endif
3734
3735 VM_Exit::set_vm_exited();
3736
3737 notify_vm_shutdown();
3738
3739 delete thread;
3740
3741 // exit_globals() will delete tty
3742 exit_globals();
3743
3744 return true;
3745 }
3746
3747
3748 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3749 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3750 return is_supported_jni_version(version);
3751 }
3752
3753
3754 jboolean Threads::is_supported_jni_version(jint version) {
3755 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3756 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3757 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3758 return JNI_FALSE;
3759 }
3760
3761
3762 void Threads::add(JavaThread* p, bool force_daemon) {
3763 // The threads lock must be owned at this point
3764 assert_locked_or_safepoint(Threads_lock);
3765
3766 // See the comment for this method in thread.hpp for its purpose and
3767 // why it is called here.
3768 p->initialize_queues();
3769 p->set_next(_thread_list);
3770 _thread_list = p;
3771 _number_of_threads++;
3772 oop threadObj = p->threadObj();
3773 bool daemon = true;
3774 // Bootstrapping problem: threadObj can be null for initial
3775 // JavaThread (or for threads attached via JNI)
3776 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3777 _number_of_non_daemon_threads++;
3778 daemon = false;
3779 }
3780
3781 ThreadService::add_thread(p, daemon);
3782
3783 // Possible GC point.
3784 Events::log("Thread added: " INTPTR_FORMAT, p);
3785 }
3786
3787 void Threads::remove(JavaThread* p) {
3788 // Extra scope needed for Thread_lock, so we can check
3789 // that we do not remove thread without safepoint code notice
3790 { MutexLocker ml(Threads_lock);
3791
3792 assert(includes(p), "p must be present");
3793
3794 JavaThread* current = _thread_list;
3795 JavaThread* prev = NULL;
3796
3797 while (current != p) {
3798 prev = current;
3799 current = current->next();
3800 }
3801
3802 if (prev) {
3803 prev->set_next(current->next());
3804 } else {
3805 _thread_list = p->next();
3806 }
3807 _number_of_threads--;
3808 oop threadObj = p->threadObj();
3809 bool daemon = true;
3810 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
3811 _number_of_non_daemon_threads--;
3812 daemon = false;
3813
3814 // Only one thread left, do a notify on the Threads_lock so a thread waiting
3815 // on destroy_vm will wake up.
3816 if (number_of_non_daemon_threads() == 1)
3817 Threads_lock->notify_all();
3818 }
3819 ThreadService::remove_thread(p, daemon);
3820
3821 // Make sure that safepoint code disregard this thread. This is needed since
3822 // the thread might mess around with locks after this point. This can cause it
3823 // to do callbacks into the safepoint code. However, the safepoint code is not aware
3824 // of this thread since it is removed from the queue.
3825 p->set_terminated_value();
3826 } // unlock Threads_lock
3827
3828 // Since Events::log uses a lock, we grab it outside the Threads_lock
3829 Events::log("Thread exited: " INTPTR_FORMAT, p);
3830 }
3831
3832 // Threads_lock must be held when this is called (or must be called during a safepoint)
3833 bool Threads::includes(JavaThread* p) {
3834 assert(Threads_lock->is_locked(), "sanity check");
3835 ALL_JAVA_THREADS(q) {
3836 if (q == p ) {
3837 return true;
3838 }
3839 }
3840 return false;
3841 }
3842
3843 // Operations on the Threads list for GC. These are not explicitly locked,
3844 // but the garbage collector must provide a safe context for them to run.
3845 // In particular, these things should never be called when the Threads_lock
3846 // is held by some other thread. (Note: the Safepoint abstraction also
3847 // uses the Threads_lock to gurantee this property. It also makes sure that
3848 // all threads gets blocked when exiting or starting).
3849
3850 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3851 ALL_JAVA_THREADS(p) {
3852 p->oops_do(f, cf);
3853 }
3854 VMThread::vm_thread()->oops_do(f, cf);
3855 }
3856
3857 void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) {
3858 // Introduce a mechanism allowing parallel threads to claim threads as
3859 // root groups. Overhead should be small enough to use all the time,
3860 // even in sequential code.
3861 SharedHeap* sh = SharedHeap::heap();
3862 bool is_par = (sh->n_par_threads() > 0);
3863 int cp = SharedHeap::heap()->strong_roots_parity();
3864 ALL_JAVA_THREADS(p) {
3865 if (p->claim_oops_do(is_par, cp)) {
3866 p->oops_do(f, cf);
3867 }
3868 }
3869 VMThread* vmt = VMThread::vm_thread();
3870 if (vmt->claim_oops_do(is_par, cp)) {
3871 vmt->oops_do(f, cf);
3872 }
3873 }
3874
3875 #ifndef SERIALGC
3876 // Used by ParallelScavenge
3877 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
3878 ALL_JAVA_THREADS(p) {
3879 q->enqueue(new ThreadRootsTask(p));
3880 }
3881 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
3882 }
3883
3884 // Used by Parallel Old
3885 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
3886 ALL_JAVA_THREADS(p) {
3887 q->enqueue(new ThreadRootsMarkingTask(p));
3888 }
3889 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
3890 }
3891 #endif // SERIALGC
3892
3893 void Threads::nmethods_do(CodeBlobClosure* cf) {
3894 ALL_JAVA_THREADS(p) {
3895 p->nmethods_do(cf);
3896 }
3897 VMThread::vm_thread()->nmethods_do(cf);
3898 }
3899
3900 void Threads::gc_epilogue() {
3901 ALL_JAVA_THREADS(p) {
3902 p->gc_epilogue();
3903 }
3904 }
3905
3906 void Threads::gc_prologue() {
3907 ALL_JAVA_THREADS(p) {
3908 p->gc_prologue();
3909 }
3910 }
3911
3912 void Threads::deoptimized_wrt_marked_nmethods() {
3913 ALL_JAVA_THREADS(p) {
3914 p->deoptimized_wrt_marked_nmethods();
3915 }
3916 }
3917
3918
3919 // Get count Java threads that are waiting to enter the specified monitor.
3920 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
3921 address monitor, bool doLock) {
3922 assert(doLock || SafepointSynchronize::is_at_safepoint(),
3923 "must grab Threads_lock or be at safepoint");
3924 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3925
3926 int i = 0;
3927 {
3928 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3929 ALL_JAVA_THREADS(p) {
3930 if (p->is_Compiler_thread()) continue;
3931
3932 address pending = (address)p->current_pending_monitor();
3933 if (pending == monitor) { // found a match
3934 if (i < count) result->append(p); // save the first count matches
3935 i++;
3936 }
3937 }
3938 }
3939 return result;
3940 }
3941
3942
3943 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
3944 assert(doLock ||
3945 Threads_lock->owned_by_self() ||
3946 SafepointSynchronize::is_at_safepoint(),
3947 "must grab Threads_lock or be at safepoint");
3948
3949 // NULL owner means not locked so we can skip the search
3950 if (owner == NULL) return NULL;
3951
3952 {
3953 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3954 ALL_JAVA_THREADS(p) {
3955 // first, see if owner is the address of a Java thread
3956 if (owner == (address)p) return p;
3957 }
3958 }
3959 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
3960 if (UseHeavyMonitors) return NULL;
3961
3962 //
3963 // If we didn't find a matching Java thread and we didn't force use of
3964 // heavyweight monitors, then the owner is the stack address of the
3965 // Lock Word in the owning Java thread's stack.
3966 //
3967 JavaThread* the_owner = NULL;
3968 {
3969 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3970 ALL_JAVA_THREADS(q) {
3971 if (q->is_lock_owned(owner)) {
3972 the_owner = q;
3973 break;
3974 }
3975 }
3976 }
3977 assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
3978 return the_owner;
3979 }
3980
3981 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
3982 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
3983 char buf[32];
3984 st->print_cr(os::local_time_string(buf, sizeof(buf)));
3985
3986 st->print_cr("Full thread dump %s (%s %s):",
3987 Abstract_VM_Version::vm_name(),
3988 Abstract_VM_Version::vm_release(),
3989 Abstract_VM_Version::vm_info_string()
3990 );
3991 st->cr();
3992
3993 #ifndef SERIALGC
3994 // Dump concurrent locks
3995 ConcurrentLocksDump concurrent_locks;
3996 if (print_concurrent_locks) {
3997 concurrent_locks.dump_at_safepoint();
3998 }
3999 #endif // SERIALGC
4000
4001 ALL_JAVA_THREADS(p) {
4002 ResourceMark rm;
4003 p->print_on(st);
4004 if (print_stacks) {
4005 if (internal_format) {
4006 p->trace_stack();
4007 } else {
4008 p->print_stack_on(st);
4009 }
4010 }
4011 st->cr();
4012 #ifndef SERIALGC
4013 if (print_concurrent_locks) {
4014 concurrent_locks.print_locks_on(p, st);
4015 }
4016 #endif // SERIALGC
4017 }
4018
4019 VMThread::vm_thread()->print_on(st);
4020 st->cr();
4021 Universe::heap()->print_gc_threads_on(st);
4022 WatcherThread* wt = WatcherThread::watcher_thread();
4023 if (wt != NULL) wt->print_on(st);
4024 st->cr();
4025 CompileBroker::print_compiler_threads_on(st);
4026 st->flush();
4027 }
4028
4029 // Threads::print_on_error() is called by fatal error handler. It's possible
4030 // that VM is not at safepoint and/or current thread is inside signal handler.
4031 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4032 // memory (even in resource area), it might deadlock the error handler.
4033 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4034 bool found_current = false;
4035 st->print_cr("Java Threads: ( => current thread )");
4036 ALL_JAVA_THREADS(thread) {
4037 bool is_current = (current == thread);
4038 found_current = found_current || is_current;
4039
4040 st->print("%s", is_current ? "=>" : " ");
4041
4042 st->print(PTR_FORMAT, thread);
4043 st->print(" ");
4044 thread->print_on_error(st, buf, buflen);
4045 st->cr();
4046 }
4047 st->cr();
4048
4049 st->print_cr("Other Threads:");
4050 if (VMThread::vm_thread()) {
4051 bool is_current = (current == VMThread::vm_thread());
4052 found_current = found_current || is_current;
4053 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4054
4055 st->print(PTR_FORMAT, VMThread::vm_thread());
4056 st->print(" ");
4057 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4058 st->cr();
4059 }
4060 WatcherThread* wt = WatcherThread::watcher_thread();
4061 if (wt != NULL) {
4062 bool is_current = (current == wt);
4063 found_current = found_current || is_current;
4064 st->print("%s", is_current ? "=>" : " ");
4065
4066 st->print(PTR_FORMAT, wt);
4067 st->print(" ");
4068 wt->print_on_error(st, buf, buflen);
4069 st->cr();
4070 }
4071 if (!found_current) {
4072 st->cr();
4073 st->print("=>" PTR_FORMAT " (exited) ", current);
4074 current->print_on_error(st, buf, buflen);
4075 st->cr();
4076 }
4077 }
4078
4079 // Internal SpinLock and Mutex
4080 // Based on ParkEvent
4081
4082 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4083 //
4084 // We employ SpinLocks _only for low-contention, fixed-length
4085 // short-duration critical sections where we're concerned
4086 // about native mutex_t or HotSpot Mutex:: latency.
4087 // The mux construct provides a spin-then-block mutual exclusion
4088 // mechanism.
4089 //
4090 // Testing has shown that contention on the ListLock guarding gFreeList
4091 // is common. If we implement ListLock as a simple SpinLock it's common
4092 // for the JVM to devolve to yielding with little progress. This is true
4093 // despite the fact that the critical sections protected by ListLock are
4094 // extremely short.
4095 //
4096 // TODO-FIXME: ListLock should be of type SpinLock.
4097 // We should make this a 1st-class type, integrated into the lock
4098 // hierarchy as leaf-locks. Critically, the SpinLock structure
4099 // should have sufficient padding to avoid false-sharing and excessive
4100 // cache-coherency traffic.
4101
4102
4103 typedef volatile int SpinLockT ;
4104
4105 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4106 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4107 return ; // normal fast-path return
4108 }
4109
4110 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4111 TEVENT (SpinAcquire - ctx) ;
4112 int ctr = 0 ;
4113 int Yields = 0 ;
4114 for (;;) {
4115 while (*adr != 0) {
4116 ++ctr ;
4117 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4118 if (Yields > 5) {
4119 // Consider using a simple NakedSleep() instead.
4120 // Then SpinAcquire could be called by non-JVM threads
4121 Thread::current()->_ParkEvent->park(1) ;
4122 } else {
4123 os::NakedYield() ;
4124 ++Yields ;
4125 }
4126 } else {
4127 SpinPause() ;
4128 }
4129 }
4130 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4131 }
4132 }
4133
4134 void Thread::SpinRelease (volatile int * adr) {
4135 assert (*adr != 0, "invariant") ;
4136 OrderAccess::fence() ; // guarantee at least release consistency.
4137 // Roach-motel semantics.
4138 // It's safe if subsequent LDs and STs float "up" into the critical section,
4139 // but prior LDs and STs within the critical section can't be allowed
4140 // to reorder or float past the ST that releases the lock.
4141 *adr = 0 ;
4142 }
4143
4144 // muxAcquire and muxRelease:
4145 //
4146 // * muxAcquire and muxRelease support a single-word lock-word construct.
4147 // The LSB of the word is set IFF the lock is held.
4148 // The remainder of the word points to the head of a singly-linked list
4149 // of threads blocked on the lock.
4150 //
4151 // * The current implementation of muxAcquire-muxRelease uses its own
4152 // dedicated Thread._MuxEvent instance. If we're interested in
4153 // minimizing the peak number of extant ParkEvent instances then
4154 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4155 // as certain invariants were satisfied. Specifically, care would need
4156 // to be taken with regards to consuming unpark() "permits".
4157 // A safe rule of thumb is that a thread would never call muxAcquire()
4158 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4159 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4160 // consume an unpark() permit intended for monitorenter, for instance.
4161 // One way around this would be to widen the restricted-range semaphore
4162 // implemented in park(). Another alternative would be to provide
4163 // multiple instances of the PlatformEvent() for each thread. One
4164 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4165 //
4166 // * Usage:
4167 // -- Only as leaf locks
4168 // -- for short-term locking only as muxAcquire does not perform
4169 // thread state transitions.
4170 //
4171 // Alternatives:
4172 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4173 // but with parking or spin-then-park instead of pure spinning.
4174 // * Use Taura-Oyama-Yonenzawa locks.
4175 // * It's possible to construct a 1-0 lock if we encode the lockword as
4176 // (List,LockByte). Acquire will CAS the full lockword while Release
4177 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4178 // acquiring threads use timers (ParkTimed) to detect and recover from
4179 // the stranding window. Thread/Node structures must be aligned on 256-byte
4180 // boundaries by using placement-new.
4181 // * Augment MCS with advisory back-link fields maintained with CAS().
4182 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4183 // The validity of the backlinks must be ratified before we trust the value.
4184 // If the backlinks are invalid the exiting thread must back-track through the
4185 // the forward links, which are always trustworthy.
4186 // * Add a successor indication. The LockWord is currently encoded as
4187 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4188 // to provide the usual futile-wakeup optimization.
4189 // See RTStt for details.
4190 // * Consider schedctl.sc_nopreempt to cover the critical section.
4191 //
4192
4193
4194 typedef volatile intptr_t MutexT ; // Mux Lock-word
4195 enum MuxBits { LOCKBIT = 1 } ;
4196
4197 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4198 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4199 if (w == 0) return ;
4200 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4201 return ;
4202 }
4203
4204 TEVENT (muxAcquire - Contention) ;
4205 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4206 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4207 for (;;) {
4208 int its = (os::is_MP() ? 100 : 0) + 1 ;
4209
4210 // Optional spin phase: spin-then-park strategy
4211 while (--its >= 0) {
4212 w = *Lock ;
4213 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4214 return ;
4215 }
4216 }
4217
4218 Self->reset() ;
4219 Self->OnList = intptr_t(Lock) ;
4220 // The following fence() isn't _strictly necessary as the subsequent
4221 // CAS() both serializes execution and ratifies the fetched *Lock value.
4222 OrderAccess::fence();
4223 for (;;) {
4224 w = *Lock ;
4225 if ((w & LOCKBIT) == 0) {
4226 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4227 Self->OnList = 0 ; // hygiene - allows stronger asserts
4228 return ;
4229 }
4230 continue ; // Interference -- *Lock changed -- Just retry
4231 }
4232 assert (w & LOCKBIT, "invariant") ;
4233 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4234 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4235 }
4236
4237 while (Self->OnList != 0) {
4238 Self->park() ;
4239 }
4240 }
4241 }
4242
4243 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4244 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4245 if (w == 0) return ;
4246 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4247 return ;
4248 }
4249
4250 TEVENT (muxAcquire - Contention) ;
4251 ParkEvent * ReleaseAfter = NULL ;
4252 if (ev == NULL) {
4253 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4254 }
4255 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4256 for (;;) {
4257 guarantee (ev->OnList == 0, "invariant") ;
4258 int its = (os::is_MP() ? 100 : 0) + 1 ;
4259
4260 // Optional spin phase: spin-then-park strategy
4261 while (--its >= 0) {
4262 w = *Lock ;
4263 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4264 if (ReleaseAfter != NULL) {
4265 ParkEvent::Release (ReleaseAfter) ;
4266 }
4267 return ;
4268 }
4269 }
4270
4271 ev->reset() ;
4272 ev->OnList = intptr_t(Lock) ;
4273 // The following fence() isn't _strictly necessary as the subsequent
4274 // CAS() both serializes execution and ratifies the fetched *Lock value.
4275 OrderAccess::fence();
4276 for (;;) {
4277 w = *Lock ;
4278 if ((w & LOCKBIT) == 0) {
4279 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4280 ev->OnList = 0 ;
4281 // We call ::Release while holding the outer lock, thus
4282 // artificially lengthening the critical section.
4283 // Consider deferring the ::Release() until the subsequent unlock(),
4284 // after we've dropped the outer lock.
4285 if (ReleaseAfter != NULL) {
4286 ParkEvent::Release (ReleaseAfter) ;
4287 }
4288 return ;
4289 }
4290 continue ; // Interference -- *Lock changed -- Just retry
4291 }
4292 assert (w & LOCKBIT, "invariant") ;
4293 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4294 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4295 }
4296
4297 while (ev->OnList != 0) {
4298 ev->park() ;
4299 }
4300 }
4301 }
4302
4303 // Release() must extract a successor from the list and then wake that thread.
4304 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4305 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4306 // Release() would :
4307 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4308 // (B) Extract a successor from the private list "in-hand"
4309 // (C) attempt to CAS() the residual back into *Lock over null.
4310 // If there were any newly arrived threads and the CAS() would fail.
4311 // In that case Release() would detach the RATs, re-merge the list in-hand
4312 // with the RATs and repeat as needed. Alternately, Release() might
4313 // detach and extract a successor, but then pass the residual list to the wakee.
4314 // The wakee would be responsible for reattaching and remerging before it
4315 // competed for the lock.
4316 //
4317 // Both "pop" and DMR are immune from ABA corruption -- there can be
4318 // multiple concurrent pushers, but only one popper or detacher.
4319 // This implementation pops from the head of the list. This is unfair,
4320 // but tends to provide excellent throughput as hot threads remain hot.
4321 // (We wake recently run threads first).
4322
4323 void Thread::muxRelease (volatile intptr_t * Lock) {
4324 for (;;) {
4325 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4326 assert (w & LOCKBIT, "invariant") ;
4327 if (w == LOCKBIT) return ;
4328 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4329 assert (List != NULL, "invariant") ;
4330 assert (List->OnList == intptr_t(Lock), "invariant") ;
4331 ParkEvent * nxt = List->ListNext ;
4332
4333 // The following CAS() releases the lock and pops the head element.
4334 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4335 continue ;
4336 }
4337 List->OnList = 0 ;
4338 OrderAccess::fence() ;
4339 List->unpark () ;
4340 return ;
4341 }
4342 }
4343
4344
4345 void Threads::verify() {
4346 ALL_JAVA_THREADS(p) {
4347 p->verify();
4348 }
4349 VMThread* thread = VMThread::vm_thread();
4350 if (thread != NULL) thread->verify();
4351 }