1 /*
2 * Copyright (c) 1997, 2016, 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/codeCache.hpp"
31 #include "code/codeCacheExtensions.hpp"
32 #include "code/scopeDesc.hpp"
33 #include "compiler/compileBroker.hpp"
34 #include "compiler/compileTask.hpp"
35 #include "gc/shared/gcId.hpp"
36 #include "gc/shared/gcLocker.inline.hpp"
37 #include "gc/shared/workgroup.hpp"
38 #include "interpreter/interpreter.hpp"
39 #include "interpreter/linkResolver.hpp"
40 #include "interpreter/oopMapCache.hpp"
41 #include "jvmtifiles/jvmtiEnv.hpp"
42 #include "logging/log.hpp"
43 #include "logging/logConfiguration.hpp"
44 #include "memory/metaspaceShared.hpp"
45 #include "memory/oopFactory.hpp"
46 #include "memory/universe.inline.hpp"
47 #include "oops/instanceKlass.hpp"
48 #include "oops/objArrayOop.hpp"
49 #include "oops/oop.inline.hpp"
50 #include "oops/symbol.hpp"
51 #include "oops/verifyOopClosure.hpp"
52 #include "prims/jvm_misc.hpp"
53 #include "prims/jvmtiExport.hpp"
54 #include "prims/jvmtiThreadState.hpp"
55 #include "prims/privilegedStack.hpp"
56 #include "runtime/arguments.hpp"
57 #include "runtime/atomic.inline.hpp"
58 #include "runtime/biasedLocking.hpp"
59 #include "runtime/commandLineFlagConstraintList.hpp"
60 #include "runtime/commandLineFlagRangeList.hpp"
61 #include "runtime/deoptimization.hpp"
62 #include "runtime/fprofiler.hpp"
63 #include "runtime/frame.inline.hpp"
64 #include "runtime/globals.hpp"
65 #include "runtime/init.hpp"
66 #include "runtime/interfaceSupport.hpp"
67 #include "runtime/java.hpp"
68 #include "runtime/javaCalls.hpp"
69 #include "runtime/jniPeriodicChecker.hpp"
70 #include "runtime/memprofiler.hpp"
71 #include "runtime/mutexLocker.hpp"
72 #include "runtime/objectMonitor.hpp"
73 #include "runtime/orderAccess.inline.hpp"
74 #include "runtime/osThread.hpp"
75 #include "runtime/safepoint.hpp"
76 #include "runtime/sharedRuntime.hpp"
77 #include "runtime/statSampler.hpp"
78 #include "runtime/stubRoutines.hpp"
79 #include "runtime/sweeper.hpp"
80 #include "runtime/task.hpp"
81 #include "runtime/thread.inline.hpp"
82 #include "runtime/threadCritical.hpp"
83 #include "runtime/vframe.hpp"
84 #include "runtime/vframeArray.hpp"
85 #include "runtime/vframe_hp.hpp"
86 #include "runtime/vmThread.hpp"
87 #include "runtime/vm_operations.hpp"
88 #include "runtime/vm_version.hpp"
89 #include "services/attachListener.hpp"
90 #include "services/management.hpp"
91 #include "services/memTracker.hpp"
92 #include "services/threadService.hpp"
93 #include "trace/traceMacros.hpp"
94 #include "trace/tracing.hpp"
95 #include "utilities/defaultStream.hpp"
96 #include "utilities/dtrace.hpp"
97 #include "utilities/events.hpp"
98 #include "utilities/macros.hpp"
99 #include "utilities/preserveException.hpp"
100 #if INCLUDE_ALL_GCS
101 #include "gc/cms/concurrentMarkSweepThread.hpp"
102 #include "gc/g1/concurrentMarkThread.inline.hpp"
103 #include "gc/parallel/pcTasks.hpp"
104 #endif // INCLUDE_ALL_GCS
105 #if INCLUDE_JVMCI
106 #include "jvmci/jvmciCompiler.hpp"
107 #include "jvmci/jvmciRuntime.hpp"
108 #endif
109 #ifdef COMPILER1
110 #include "c1/c1_Compiler.hpp"
111 #endif
112 #ifdef COMPILER2
113 #include "opto/c2compiler.hpp"
114 #include "opto/idealGraphPrinter.hpp"
115 #endif
116 #if INCLUDE_RTM_OPT
117 #include "runtime/rtmLocking.hpp"
118 #endif
119
120 #ifdef DTRACE_ENABLED
121
122 // Only bother with this argument setup if dtrace is available
123
124 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
125 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
126
127 #define DTRACE_THREAD_PROBE(probe, javathread) \
128 { \
129 ResourceMark rm(this); \
130 int len = 0; \
131 const char* name = (javathread)->get_thread_name(); \
132 len = strlen(name); \
133 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
134 (char *) name, len, \
135 java_lang_Thread::thread_id((javathread)->threadObj()), \
136 (uintptr_t) (javathread)->osthread()->thread_id(), \
137 java_lang_Thread::is_daemon((javathread)->threadObj())); \
138 }
139
140 #else // ndef DTRACE_ENABLED
141
142 #define DTRACE_THREAD_PROBE(probe, javathread)
143
144 #endif // ndef DTRACE_ENABLED
145
146 #ifndef USE_LIBRARY_BASED_TLS_ONLY
147 // Current thread is maintained as a thread-local variable
148 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
149 #endif
150
151 // Class hierarchy
152 // - Thread
153 // - VMThread
154 // - WatcherThread
155 // - ConcurrentMarkSweepThread
156 // - JavaThread
157 // - CompilerThread
158
159 // ======= Thread ========
160 // Support for forcing alignment of thread objects for biased locking
161 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
162 if (UseBiasedLocking) {
163 const int alignment = markOopDesc::biased_lock_alignment;
164 size_t aligned_size = size + (alignment - sizeof(intptr_t));
165 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
166 : AllocateHeap(aligned_size, flags, CURRENT_PC,
167 AllocFailStrategy::RETURN_NULL);
168 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
169 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
170 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
171 "JavaThread alignment code overflowed allocated storage");
172 if (TraceBiasedLocking) {
173 if (aligned_addr != real_malloc_addr) {
174 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
175 p2i(real_malloc_addr), p2i(aligned_addr));
176 }
177 }
178 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
179 return aligned_addr;
180 } else {
181 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
182 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
183 }
184 }
185
186 void Thread::operator delete(void* p) {
187 if (UseBiasedLocking) {
188 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
189 FreeHeap(real_malloc_addr);
190 } else {
191 FreeHeap(p);
192 }
193 }
194
195
196 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
197 // JavaThread
198
199
200 Thread::Thread() {
201 // stack and get_thread
202 set_stack_base(NULL);
203 set_stack_size(0);
204 set_self_raw_id(0);
205 set_lgrp_id(-1);
206 DEBUG_ONLY(clear_suspendible_thread();)
207
208 // allocated data structures
209 set_osthread(NULL);
210 set_resource_area(new (mtThread)ResourceArea());
211 DEBUG_ONLY(_current_resource_mark = NULL;)
212 set_handle_area(new (mtThread) HandleArea(NULL));
213 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
214 set_active_handles(NULL);
215 set_free_handle_block(NULL);
216 set_last_handle_mark(NULL);
217
218 // This initial value ==> never claimed.
219 _oops_do_parity = 0;
220
221 // the handle mark links itself to last_handle_mark
222 new HandleMark(this);
223
224 // plain initialization
225 debug_only(_owned_locks = NULL;)
226 debug_only(_allow_allocation_count = 0;)
227 NOT_PRODUCT(_allow_safepoint_count = 0;)
228 NOT_PRODUCT(_skip_gcalot = false;)
229 _jvmti_env_iteration_count = 0;
230 set_allocated_bytes(0);
231 _vm_operation_started_count = 0;
232 _vm_operation_completed_count = 0;
233 _current_pending_monitor = NULL;
234 _current_pending_monitor_is_from_java = true;
235 _current_waiting_monitor = NULL;
236 _num_nested_signal = 0;
237 omFreeList = NULL;
238 omFreeCount = 0;
239 omFreeProvision = 32;
240 omInUseList = NULL;
241 omInUseCount = 0;
242
243 #ifdef ASSERT
244 _visited_for_critical_count = false;
245 #endif
246
247 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
248 Monitor::_safepoint_check_sometimes);
249 _suspend_flags = 0;
250
251 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
252 _hashStateX = os::random();
253 _hashStateY = 842502087;
254 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
255 _hashStateW = 273326509;
256
257 _OnTrap = 0;
258 _schedctl = NULL;
259 _Stalled = 0;
260 _TypeTag = 0x2BAD;
261
262 // Many of the following fields are effectively final - immutable
263 // Note that nascent threads can't use the Native Monitor-Mutex
264 // construct until the _MutexEvent is initialized ...
265 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
266 // we might instead use a stack of ParkEvents that we could provision on-demand.
267 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
268 // and ::Release()
269 _ParkEvent = ParkEvent::Allocate(this);
270 _SleepEvent = ParkEvent::Allocate(this);
271 _MutexEvent = ParkEvent::Allocate(this);
272 _MuxEvent = ParkEvent::Allocate(this);
273
274 #ifdef CHECK_UNHANDLED_OOPS
275 if (CheckUnhandledOops) {
276 _unhandled_oops = new UnhandledOops(this);
277 }
278 #endif // CHECK_UNHANDLED_OOPS
279 #ifdef ASSERT
280 if (UseBiasedLocking) {
281 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
282 assert(this == _real_malloc_address ||
283 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
284 "bug in forced alignment of thread objects");
285 }
286 #endif // ASSERT
287 }
288
289 void Thread::initialize_thread_current() {
290 #ifndef USE_LIBRARY_BASED_TLS_ONLY
291 assert(_thr_current == NULL, "Thread::current already initialized");
292 _thr_current = this;
293 #endif
294 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
295 ThreadLocalStorage::set_thread(this);
296 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
297 }
298
299 void Thread::clear_thread_current() {
300 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
301 #ifndef USE_LIBRARY_BASED_TLS_ONLY
302 _thr_current = NULL;
303 #endif
304 ThreadLocalStorage::set_thread(NULL);
305 }
306
307 void Thread::record_stack_base_and_size() {
308 set_stack_base(os::current_stack_base());
309 set_stack_size(os::current_stack_size());
310 // CR 7190089: on Solaris, primordial thread's stack is adjusted
311 // in initialize_thread(). Without the adjustment, stack size is
312 // incorrect if stack is set to unlimited (ulimit -s unlimited).
313 // So far, only Solaris has real implementation of initialize_thread().
314 //
315 // set up any platform-specific state.
316 os::initialize_thread(this);
317
318 // Set stack limits after thread is initialized.
319 if (is_Java_thread()) {
320 ((JavaThread*) this)->set_stack_overflow_limit();
321 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
322 }
323 #if INCLUDE_NMT
324 // record thread's native stack, stack grows downward
325 MemTracker::record_thread_stack(stack_end(), stack_size());
326 #endif // INCLUDE_NMT
327 }
328
329
330 Thread::~Thread() {
331 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
332 ObjectSynchronizer::omFlush(this);
333
334 EVENT_THREAD_DESTRUCT(this);
335
336 // stack_base can be NULL if the thread is never started or exited before
337 // record_stack_base_and_size called. Although, we would like to ensure
338 // that all started threads do call record_stack_base_and_size(), there is
339 // not proper way to enforce that.
340 #if INCLUDE_NMT
341 if (_stack_base != NULL) {
342 MemTracker::release_thread_stack(stack_end(), stack_size());
343 #ifdef ASSERT
344 set_stack_base(NULL);
345 #endif
346 }
347 #endif // INCLUDE_NMT
348
349 // deallocate data structures
350 delete resource_area();
351 // since the handle marks are using the handle area, we have to deallocated the root
352 // handle mark before deallocating the thread's handle area,
353 assert(last_handle_mark() != NULL, "check we have an element");
354 delete last_handle_mark();
355 assert(last_handle_mark() == NULL, "check we have reached the end");
356
357 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
358 // We NULL out the fields for good hygiene.
359 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
360 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
361 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
362 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
363
364 delete handle_area();
365 delete metadata_handles();
366
367 // osthread() can be NULL, if creation of thread failed.
368 if (osthread() != NULL) os::free_thread(osthread());
369
370 delete _SR_lock;
371
372 // clear Thread::current if thread is deleting itself.
373 // Needed to ensure JNI correctly detects non-attached threads.
374 if (this == Thread::current()) {
375 clear_thread_current();
376 }
377
378 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
379 }
380
381 // NOTE: dummy function for assertion purpose.
382 void Thread::run() {
383 ShouldNotReachHere();
384 }
385
386 #ifdef ASSERT
387 // Private method to check for dangling thread pointer
388 void check_for_dangling_thread_pointer(Thread *thread) {
389 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
390 "possibility of dangling Thread pointer");
391 }
392 #endif
393
394 ThreadPriority Thread::get_priority(const Thread* const thread) {
395 ThreadPriority priority;
396 // Can return an error!
397 (void)os::get_priority(thread, priority);
398 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
399 return priority;
400 }
401
402 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
403 debug_only(check_for_dangling_thread_pointer(thread);)
404 // Can return an error!
405 (void)os::set_priority(thread, priority);
406 }
407
408
409 void Thread::start(Thread* thread) {
410 // Start is different from resume in that its safety is guaranteed by context or
411 // being called from a Java method synchronized on the Thread object.
412 if (!DisableStartThread) {
413 if (thread->is_Java_thread()) {
414 // Initialize the thread state to RUNNABLE before starting this thread.
415 // Can not set it after the thread started because we do not know the
416 // exact thread state at that time. It could be in MONITOR_WAIT or
417 // in SLEEPING or some other state.
418 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
419 java_lang_Thread::RUNNABLE);
420 }
421 os::start_thread(thread);
422 }
423 }
424
425 // Enqueue a VM_Operation to do the job for us - sometime later
426 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
427 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
428 VMThread::execute(vm_stop);
429 }
430
431
432 // Check if an external suspend request has completed (or has been
433 // cancelled). Returns true if the thread is externally suspended and
434 // false otherwise.
435 //
436 // The bits parameter returns information about the code path through
437 // the routine. Useful for debugging:
438 //
439 // set in is_ext_suspend_completed():
440 // 0x00000001 - routine was entered
441 // 0x00000010 - routine return false at end
442 // 0x00000100 - thread exited (return false)
443 // 0x00000200 - suspend request cancelled (return false)
444 // 0x00000400 - thread suspended (return true)
445 // 0x00001000 - thread is in a suspend equivalent state (return true)
446 // 0x00002000 - thread is native and walkable (return true)
447 // 0x00004000 - thread is native_trans and walkable (needed retry)
448 //
449 // set in wait_for_ext_suspend_completion():
450 // 0x00010000 - routine was entered
451 // 0x00020000 - suspend request cancelled before loop (return false)
452 // 0x00040000 - thread suspended before loop (return true)
453 // 0x00080000 - suspend request cancelled in loop (return false)
454 // 0x00100000 - thread suspended in loop (return true)
455 // 0x00200000 - suspend not completed during retry loop (return false)
456
457 // Helper class for tracing suspend wait debug bits.
458 //
459 // 0x00000100 indicates that the target thread exited before it could
460 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
461 // 0x00080000 each indicate a cancelled suspend request so they don't
462 // count as wait failures either.
463 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
464
465 class TraceSuspendDebugBits : public StackObj {
466 private:
467 JavaThread * jt;
468 bool is_wait;
469 bool called_by_wait; // meaningful when !is_wait
470 uint32_t * bits;
471
472 public:
473 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
474 uint32_t *_bits) {
475 jt = _jt;
476 is_wait = _is_wait;
477 called_by_wait = _called_by_wait;
478 bits = _bits;
479 }
480
481 ~TraceSuspendDebugBits() {
482 if (!is_wait) {
483 #if 1
484 // By default, don't trace bits for is_ext_suspend_completed() calls.
485 // That trace is very chatty.
486 return;
487 #else
488 if (!called_by_wait) {
489 // If tracing for is_ext_suspend_completed() is enabled, then only
490 // trace calls to it from wait_for_ext_suspend_completion()
491 return;
492 }
493 #endif
494 }
495
496 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
497 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
498 MutexLocker ml(Threads_lock); // needed for get_thread_name()
499 ResourceMark rm;
500
501 tty->print_cr(
502 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
503 jt->get_thread_name(), *bits);
504
505 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
506 }
507 }
508 }
509 };
510 #undef DEBUG_FALSE_BITS
511
512
513 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
514 uint32_t *bits) {
515 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
516
517 bool did_trans_retry = false; // only do thread_in_native_trans retry once
518 bool do_trans_retry; // flag to force the retry
519
520 *bits |= 0x00000001;
521
522 do {
523 do_trans_retry = false;
524
525 if (is_exiting()) {
526 // Thread is in the process of exiting. This is always checked
527 // first to reduce the risk of dereferencing a freed JavaThread.
528 *bits |= 0x00000100;
529 return false;
530 }
531
532 if (!is_external_suspend()) {
533 // Suspend request is cancelled. This is always checked before
534 // is_ext_suspended() to reduce the risk of a rogue resume
535 // confusing the thread that made the suspend request.
536 *bits |= 0x00000200;
537 return false;
538 }
539
540 if (is_ext_suspended()) {
541 // thread is suspended
542 *bits |= 0x00000400;
543 return true;
544 }
545
546 // Now that we no longer do hard suspends of threads running
547 // native code, the target thread can be changing thread state
548 // while we are in this routine:
549 //
550 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
551 //
552 // We save a copy of the thread state as observed at this moment
553 // and make our decision about suspend completeness based on the
554 // copy. This closes the race where the thread state is seen as
555 // _thread_in_native_trans in the if-thread_blocked check, but is
556 // seen as _thread_blocked in if-thread_in_native_trans check.
557 JavaThreadState save_state = thread_state();
558
559 if (save_state == _thread_blocked && is_suspend_equivalent()) {
560 // If the thread's state is _thread_blocked and this blocking
561 // condition is known to be equivalent to a suspend, then we can
562 // consider the thread to be externally suspended. This means that
563 // the code that sets _thread_blocked has been modified to do
564 // self-suspension if the blocking condition releases. We also
565 // used to check for CONDVAR_WAIT here, but that is now covered by
566 // the _thread_blocked with self-suspension check.
567 //
568 // Return true since we wouldn't be here unless there was still an
569 // external suspend request.
570 *bits |= 0x00001000;
571 return true;
572 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
573 // Threads running native code will self-suspend on native==>VM/Java
574 // transitions. If its stack is walkable (should always be the case
575 // unless this function is called before the actual java_suspend()
576 // call), then the wait is done.
577 *bits |= 0x00002000;
578 return true;
579 } else if (!called_by_wait && !did_trans_retry &&
580 save_state == _thread_in_native_trans &&
581 frame_anchor()->walkable()) {
582 // The thread is transitioning from thread_in_native to another
583 // thread state. check_safepoint_and_suspend_for_native_trans()
584 // will force the thread to self-suspend. If it hasn't gotten
585 // there yet we may have caught the thread in-between the native
586 // code check above and the self-suspend. Lucky us. If we were
587 // called by wait_for_ext_suspend_completion(), then it
588 // will be doing the retries so we don't have to.
589 //
590 // Since we use the saved thread state in the if-statement above,
591 // there is a chance that the thread has already transitioned to
592 // _thread_blocked by the time we get here. In that case, we will
593 // make a single unnecessary pass through the logic below. This
594 // doesn't hurt anything since we still do the trans retry.
595
596 *bits |= 0x00004000;
597
598 // Once the thread leaves thread_in_native_trans for another
599 // thread state, we break out of this retry loop. We shouldn't
600 // need this flag to prevent us from getting back here, but
601 // sometimes paranoia is good.
602 did_trans_retry = true;
603
604 // We wait for the thread to transition to a more usable state.
605 for (int i = 1; i <= SuspendRetryCount; i++) {
606 // We used to do an "os::yield_all(i)" call here with the intention
607 // that yielding would increase on each retry. However, the parameter
608 // is ignored on Linux which means the yield didn't scale up. Waiting
609 // on the SR_lock below provides a much more predictable scale up for
610 // the delay. It also provides a simple/direct point to check for any
611 // safepoint requests from the VMThread
612
613 // temporarily drops SR_lock while doing wait with safepoint check
614 // (if we're a JavaThread - the WatcherThread can also call this)
615 // and increase delay with each retry
616 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
617
618 // check the actual thread state instead of what we saved above
619 if (thread_state() != _thread_in_native_trans) {
620 // the thread has transitioned to another thread state so
621 // try all the checks (except this one) one more time.
622 do_trans_retry = true;
623 break;
624 }
625 } // end retry loop
626
627
628 }
629 } while (do_trans_retry);
630
631 *bits |= 0x00000010;
632 return false;
633 }
634
635 // Wait for an external suspend request to complete (or be cancelled).
636 // Returns true if the thread is externally suspended and false otherwise.
637 //
638 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
639 uint32_t *bits) {
640 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
641 false /* !called_by_wait */, bits);
642
643 // local flag copies to minimize SR_lock hold time
644 bool is_suspended;
645 bool pending;
646 uint32_t reset_bits;
647
648 // set a marker so is_ext_suspend_completed() knows we are the caller
649 *bits |= 0x00010000;
650
651 // We use reset_bits to reinitialize the bits value at the top of
652 // each retry loop. This allows the caller to make use of any
653 // unused bits for their own marking purposes.
654 reset_bits = *bits;
655
656 {
657 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
658 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
659 delay, bits);
660 pending = is_external_suspend();
661 }
662 // must release SR_lock to allow suspension to complete
663
664 if (!pending) {
665 // A cancelled suspend request is the only false return from
666 // is_ext_suspend_completed() that keeps us from entering the
667 // retry loop.
668 *bits |= 0x00020000;
669 return false;
670 }
671
672 if (is_suspended) {
673 *bits |= 0x00040000;
674 return true;
675 }
676
677 for (int i = 1; i <= retries; i++) {
678 *bits = reset_bits; // reinit to only track last retry
679
680 // We used to do an "os::yield_all(i)" call here with the intention
681 // that yielding would increase on each retry. However, the parameter
682 // is ignored on Linux which means the yield didn't scale up. Waiting
683 // on the SR_lock below provides a much more predictable scale up for
684 // the delay. It also provides a simple/direct point to check for any
685 // safepoint requests from the VMThread
686
687 {
688 MutexLocker ml(SR_lock());
689 // wait with safepoint check (if we're a JavaThread - the WatcherThread
690 // can also call this) and increase delay with each retry
691 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
692
693 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
694 delay, bits);
695
696 // It is possible for the external suspend request to be cancelled
697 // (by a resume) before the actual suspend operation is completed.
698 // Refresh our local copy to see if we still need to wait.
699 pending = is_external_suspend();
700 }
701
702 if (!pending) {
703 // A cancelled suspend request is the only false return from
704 // is_ext_suspend_completed() that keeps us from staying in the
705 // retry loop.
706 *bits |= 0x00080000;
707 return false;
708 }
709
710 if (is_suspended) {
711 *bits |= 0x00100000;
712 return true;
713 }
714 } // end retry loop
715
716 // thread did not suspend after all our retries
717 *bits |= 0x00200000;
718 return false;
719 }
720
721 #ifndef PRODUCT
722 void JavaThread::record_jump(address target, address instr, const char* file,
723 int line) {
724
725 // This should not need to be atomic as the only way for simultaneous
726 // updates is via interrupts. Even then this should be rare or non-existent
727 // and we don't care that much anyway.
728
729 int index = _jmp_ring_index;
730 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
731 _jmp_ring[index]._target = (intptr_t) target;
732 _jmp_ring[index]._instruction = (intptr_t) instr;
733 _jmp_ring[index]._file = file;
734 _jmp_ring[index]._line = line;
735 }
736 #endif // PRODUCT
737
738 // Called by flat profiler
739 // Callers have already called wait_for_ext_suspend_completion
740 // The assertion for that is currently too complex to put here:
741 bool JavaThread::profile_last_Java_frame(frame* _fr) {
742 bool gotframe = false;
743 // self suspension saves needed state.
744 if (has_last_Java_frame() && _anchor.walkable()) {
745 *_fr = pd_last_frame();
746 gotframe = true;
747 }
748 return gotframe;
749 }
750
751 void Thread::interrupt(Thread* thread) {
752 debug_only(check_for_dangling_thread_pointer(thread);)
753 os::interrupt(thread);
754 }
755
756 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
757 debug_only(check_for_dangling_thread_pointer(thread);)
758 // Note: If clear_interrupted==false, this simply fetches and
759 // returns the value of the field osthread()->interrupted().
760 return os::is_interrupted(thread, clear_interrupted);
761 }
762
763
764 // GC Support
765 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
766 jint thread_parity = _oops_do_parity;
767 if (thread_parity != strong_roots_parity) {
768 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
769 if (res == thread_parity) {
770 return true;
771 } else {
772 guarantee(res == strong_roots_parity, "Or else what?");
773 return false;
774 }
775 }
776 return false;
777 }
778
779 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
780 active_handles()->oops_do(f);
781 // Do oop for ThreadShadow
782 f->do_oop((oop*)&_pending_exception);
783 handle_area()->oops_do(f);
784 }
785
786 void Thread::nmethods_do(CodeBlobClosure* cf) {
787 // no nmethods in a generic thread...
788 }
789
790 void Thread::metadata_handles_do(void f(Metadata*)) {
791 // Only walk the Handles in Thread.
792 if (metadata_handles() != NULL) {
793 for (int i = 0; i< metadata_handles()->length(); i++) {
794 f(metadata_handles()->at(i));
795 }
796 }
797 }
798
799 void Thread::print_on(outputStream* st) const {
800 // get_priority assumes osthread initialized
801 if (osthread() != NULL) {
802 int os_prio;
803 if (os::get_native_priority(this, &os_prio) == OS_OK) {
804 st->print("os_prio=%d ", os_prio);
805 }
806 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
807 ext().print_on(st);
808 osthread()->print_on(st);
809 }
810 debug_only(if (WizardMode) print_owned_locks_on(st);)
811 }
812
813 // Thread::print_on_error() is called by fatal error handler. Don't use
814 // any lock or allocate memory.
815 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
816 if (is_VM_thread()) st->print("VMThread");
817 else if (is_Compiler_thread()) st->print("CompilerThread");
818 else if (is_Java_thread()) st->print("JavaThread");
819 else if (is_GC_task_thread()) st->print("GCTaskThread");
820 else if (is_Watcher_thread()) st->print("WatcherThread");
821 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
822 else st->print("Thread");
823
824 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
825 p2i(stack_end()), p2i(stack_base()));
826
827 if (osthread()) {
828 st->print(" [id=%d]", osthread()->thread_id());
829 }
830 }
831
832 #ifdef ASSERT
833 void Thread::print_owned_locks_on(outputStream* st) const {
834 Monitor *cur = _owned_locks;
835 if (cur == NULL) {
836 st->print(" (no locks) ");
837 } else {
838 st->print_cr(" Locks owned:");
839 while (cur) {
840 cur->print_on(st);
841 cur = cur->next();
842 }
843 }
844 }
845
846 static int ref_use_count = 0;
847
848 bool Thread::owns_locks_but_compiled_lock() const {
849 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
850 if (cur != Compile_lock) return true;
851 }
852 return false;
853 }
854
855
856 #endif
857
858 #ifndef PRODUCT
859
860 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
861 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
862 // no threads which allow_vm_block's are held
863 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
864 // Check if current thread is allowed to block at a safepoint
865 if (!(_allow_safepoint_count == 0)) {
866 fatal("Possible safepoint reached by thread that does not allow it");
867 }
868 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
869 fatal("LEAF method calling lock?");
870 }
871
872 #ifdef ASSERT
873 if (potential_vm_operation && is_Java_thread()
874 && !Universe::is_bootstrapping()) {
875 // Make sure we do not hold any locks that the VM thread also uses.
876 // This could potentially lead to deadlocks
877 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
878 // Threads_lock is special, since the safepoint synchronization will not start before this is
879 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
880 // since it is used to transfer control between JavaThreads and the VMThread
881 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
882 if ((cur->allow_vm_block() &&
883 cur != Threads_lock &&
884 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
885 cur != VMOperationRequest_lock &&
886 cur != VMOperationQueue_lock) ||
887 cur->rank() == Mutex::special) {
888 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
889 }
890 }
891 }
892
893 if (GCALotAtAllSafepoints) {
894 // We could enter a safepoint here and thus have a gc
895 InterfaceSupport::check_gc_alot();
896 }
897 #endif
898 }
899 #endif
900
901 bool Thread::is_in_stack(address adr) const {
902 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
903 address end = os::current_stack_pointer();
904 // Allow non Java threads to call this without stack_base
905 if (_stack_base == NULL) return true;
906 if (stack_base() >= adr && adr >= end) return true;
907
908 return false;
909 }
910
911 bool Thread::is_in_usable_stack(address adr) const {
912 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
913 size_t usable_stack_size = _stack_size - stack_guard_size;
914
915 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
916 }
917
918
919 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
920 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
921 // used for compilation in the future. If that change is made, the need for these methods
922 // should be revisited, and they should be removed if possible.
923
924 bool Thread::is_lock_owned(address adr) const {
925 return on_local_stack(adr);
926 }
927
928 bool Thread::set_as_starting_thread() {
929 // NOTE: this must be called inside the main thread.
930 return os::create_main_thread((JavaThread*)this);
931 }
932
933 static void initialize_class(Symbol* class_name, TRAPS) {
934 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
935 InstanceKlass::cast(klass)->initialize(CHECK);
936 }
937
938
939 // Creates the initial ThreadGroup
940 static Handle create_initial_thread_group(TRAPS) {
941 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
942 instanceKlassHandle klass (THREAD, k);
943
944 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
945 {
946 JavaValue result(T_VOID);
947 JavaCalls::call_special(&result,
948 system_instance,
949 klass,
950 vmSymbols::object_initializer_name(),
951 vmSymbols::void_method_signature(),
952 CHECK_NH);
953 }
954 Universe::set_system_thread_group(system_instance());
955
956 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
957 {
958 JavaValue result(T_VOID);
959 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
960 JavaCalls::call_special(&result,
961 main_instance,
962 klass,
963 vmSymbols::object_initializer_name(),
964 vmSymbols::threadgroup_string_void_signature(),
965 system_instance,
966 string,
967 CHECK_NH);
968 }
969 return main_instance;
970 }
971
972 // Creates the initial Thread
973 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
974 TRAPS) {
975 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
976 instanceKlassHandle klass (THREAD, k);
977 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
978
979 java_lang_Thread::set_thread(thread_oop(), thread);
980 java_lang_Thread::set_priority(thread_oop(), NormPriority);
981 thread->set_threadObj(thread_oop());
982
983 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
984
985 JavaValue result(T_VOID);
986 JavaCalls::call_special(&result, thread_oop,
987 klass,
988 vmSymbols::object_initializer_name(),
989 vmSymbols::threadgroup_string_void_signature(),
990 thread_group,
991 string,
992 CHECK_NULL);
993 return thread_oop();
994 }
995
996 static void call_initializeSystemClass(TRAPS) {
997 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
998 instanceKlassHandle klass (THREAD, k);
999
1000 JavaValue result(T_VOID);
1001 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1002 vmSymbols::void_method_signature(), CHECK);
1003 }
1004
1005 char java_runtime_name[128] = "";
1006 char java_runtime_version[128] = "";
1007
1008 // extract the JRE name from sun.misc.Version.java_runtime_name
1009 static const char* get_java_runtime_name(TRAPS) {
1010 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1011 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1012 fieldDescriptor fd;
1013 bool found = k != NULL &&
1014 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1015 vmSymbols::string_signature(), &fd);
1016 if (found) {
1017 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1018 if (name_oop == NULL) {
1019 return NULL;
1020 }
1021 const char* name = java_lang_String::as_utf8_string(name_oop,
1022 java_runtime_name,
1023 sizeof(java_runtime_name));
1024 return name;
1025 } else {
1026 return NULL;
1027 }
1028 }
1029
1030 // extract the JRE version from sun.misc.Version.java_runtime_version
1031 static const char* get_java_runtime_version(TRAPS) {
1032 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1033 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1034 fieldDescriptor fd;
1035 bool found = k != NULL &&
1036 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1037 vmSymbols::string_signature(), &fd);
1038 if (found) {
1039 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1040 if (name_oop == NULL) {
1041 return NULL;
1042 }
1043 const char* name = java_lang_String::as_utf8_string(name_oop,
1044 java_runtime_version,
1045 sizeof(java_runtime_version));
1046 return name;
1047 } else {
1048 return NULL;
1049 }
1050 }
1051
1052 // General purpose hook into Java code, run once when the VM is initialized.
1053 // The Java library method itself may be changed independently from the VM.
1054 static void call_postVMInitHook(TRAPS) {
1055 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1056 instanceKlassHandle klass (THREAD, k);
1057 if (klass.not_null()) {
1058 JavaValue result(T_VOID);
1059 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1060 vmSymbols::void_method_signature(),
1061 CHECK);
1062 }
1063 }
1064
1065 static void reset_vm_info_property(TRAPS) {
1066 // the vm info string
1067 ResourceMark rm(THREAD);
1068 const char *vm_info = VM_Version::vm_info_string();
1069
1070 // java.lang.System class
1071 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1072 instanceKlassHandle klass (THREAD, k);
1073
1074 // setProperty arguments
1075 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1076 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1077
1078 // return value
1079 JavaValue r(T_OBJECT);
1080
1081 // public static String setProperty(String key, String value);
1082 JavaCalls::call_static(&r,
1083 klass,
1084 vmSymbols::setProperty_name(),
1085 vmSymbols::string_string_string_signature(),
1086 key_str,
1087 value_str,
1088 CHECK);
1089 }
1090
1091
1092 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1093 bool daemon, TRAPS) {
1094 assert(thread_group.not_null(), "thread group should be specified");
1095 assert(threadObj() == NULL, "should only create Java thread object once");
1096
1097 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1098 instanceKlassHandle klass (THREAD, k);
1099 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1100
1101 java_lang_Thread::set_thread(thread_oop(), this);
1102 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1103 set_threadObj(thread_oop());
1104
1105 JavaValue result(T_VOID);
1106 if (thread_name != NULL) {
1107 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1108 // Thread gets assigned specified name and null target
1109 JavaCalls::call_special(&result,
1110 thread_oop,
1111 klass,
1112 vmSymbols::object_initializer_name(),
1113 vmSymbols::threadgroup_string_void_signature(),
1114 thread_group, // Argument 1
1115 name, // Argument 2
1116 THREAD);
1117 } else {
1118 // Thread gets assigned name "Thread-nnn" and null target
1119 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1120 JavaCalls::call_special(&result,
1121 thread_oop,
1122 klass,
1123 vmSymbols::object_initializer_name(),
1124 vmSymbols::threadgroup_runnable_void_signature(),
1125 thread_group, // Argument 1
1126 Handle(), // Argument 2
1127 THREAD);
1128 }
1129
1130
1131 if (daemon) {
1132 java_lang_Thread::set_daemon(thread_oop());
1133 }
1134
1135 if (HAS_PENDING_EXCEPTION) {
1136 return;
1137 }
1138
1139 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1140 Handle threadObj(THREAD, this->threadObj());
1141
1142 JavaCalls::call_special(&result,
1143 thread_group,
1144 group,
1145 vmSymbols::add_method_name(),
1146 vmSymbols::thread_void_signature(),
1147 threadObj, // Arg 1
1148 THREAD);
1149 }
1150
1151 // NamedThread -- non-JavaThread subclasses with multiple
1152 // uniquely named instances should derive from this.
1153 NamedThread::NamedThread() : Thread() {
1154 _name = NULL;
1155 _processed_thread = NULL;
1156 _gc_id = GCId::undefined();
1157 }
1158
1159 NamedThread::~NamedThread() {
1160 if (_name != NULL) {
1161 FREE_C_HEAP_ARRAY(char, _name);
1162 _name = NULL;
1163 }
1164 }
1165
1166 void NamedThread::set_name(const char* format, ...) {
1167 guarantee(_name == NULL, "Only get to set name once.");
1168 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1169 guarantee(_name != NULL, "alloc failure");
1170 va_list ap;
1171 va_start(ap, format);
1172 jio_vsnprintf(_name, max_name_len, format, ap);
1173 va_end(ap);
1174 }
1175
1176 void NamedThread::initialize_named_thread() {
1177 set_native_thread_name(name());
1178 }
1179
1180 void NamedThread::print_on(outputStream* st) const {
1181 st->print("\"%s\" ", name());
1182 Thread::print_on(st);
1183 st->cr();
1184 }
1185
1186
1187 // ======= WatcherThread ========
1188
1189 // The watcher thread exists to simulate timer interrupts. It should
1190 // be replaced by an abstraction over whatever native support for
1191 // timer interrupts exists on the platform.
1192
1193 WatcherThread* WatcherThread::_watcher_thread = NULL;
1194 bool WatcherThread::_startable = false;
1195 volatile bool WatcherThread::_should_terminate = false;
1196
1197 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1198 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1199 if (os::create_thread(this, os::watcher_thread)) {
1200 _watcher_thread = this;
1201
1202 // Set the watcher thread to the highest OS priority which should not be
1203 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1204 // is created. The only normal thread using this priority is the reference
1205 // handler thread, which runs for very short intervals only.
1206 // If the VMThread's priority is not lower than the WatcherThread profiling
1207 // will be inaccurate.
1208 os::set_priority(this, MaxPriority);
1209 if (!DisableStartThread) {
1210 os::start_thread(this);
1211 }
1212 }
1213 }
1214
1215 int WatcherThread::sleep() const {
1216 // The WatcherThread does not participate in the safepoint protocol
1217 // for the PeriodicTask_lock because it is not a JavaThread.
1218 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1219
1220 if (_should_terminate) {
1221 // check for termination before we do any housekeeping or wait
1222 return 0; // we did not sleep.
1223 }
1224
1225 // remaining will be zero if there are no tasks,
1226 // causing the WatcherThread to sleep until a task is
1227 // enrolled
1228 int remaining = PeriodicTask::time_to_wait();
1229 int time_slept = 0;
1230
1231 // we expect this to timeout - we only ever get unparked when
1232 // we should terminate or when a new task has been enrolled
1233 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1234
1235 jlong time_before_loop = os::javaTimeNanos();
1236
1237 while (true) {
1238 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1239 remaining);
1240 jlong now = os::javaTimeNanos();
1241
1242 if (remaining == 0) {
1243 // if we didn't have any tasks we could have waited for a long time
1244 // consider the time_slept zero and reset time_before_loop
1245 time_slept = 0;
1246 time_before_loop = now;
1247 } else {
1248 // need to recalculate since we might have new tasks in _tasks
1249 time_slept = (int) ((now - time_before_loop) / 1000000);
1250 }
1251
1252 // Change to task list or spurious wakeup of some kind
1253 if (timedout || _should_terminate) {
1254 break;
1255 }
1256
1257 remaining = PeriodicTask::time_to_wait();
1258 if (remaining == 0) {
1259 // Last task was just disenrolled so loop around and wait until
1260 // another task gets enrolled
1261 continue;
1262 }
1263
1264 remaining -= time_slept;
1265 if (remaining <= 0) {
1266 break;
1267 }
1268 }
1269
1270 return time_slept;
1271 }
1272
1273 void WatcherThread::run() {
1274 assert(this == watcher_thread(), "just checking");
1275
1276 this->record_stack_base_and_size();
1277 this->set_native_thread_name(this->name());
1278 this->set_active_handles(JNIHandleBlock::allocate_block());
1279 while (true) {
1280 assert(watcher_thread() == Thread::current(), "thread consistency check");
1281 assert(watcher_thread() == this, "thread consistency check");
1282
1283 // Calculate how long it'll be until the next PeriodicTask work
1284 // should be done, and sleep that amount of time.
1285 int time_waited = sleep();
1286
1287 if (is_error_reported()) {
1288 // A fatal error has happened, the error handler(VMError::report_and_die)
1289 // should abort JVM after creating an error log file. However in some
1290 // rare cases, the error handler itself might deadlock. Here we try to
1291 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1292 //
1293 // This code is in WatcherThread because WatcherThread wakes up
1294 // periodically so the fatal error handler doesn't need to do anything;
1295 // also because the WatcherThread is less likely to crash than other
1296 // threads.
1297
1298 for (;;) {
1299 if (!ShowMessageBoxOnError
1300 && (OnError == NULL || OnError[0] == '\0')
1301 && Arguments::abort_hook() == NULL) {
1302 os::sleep(this, (jlong)ErrorLogTimeout * 1000, false); // in seconds
1303 fdStream err(defaultStream::output_fd());
1304 err.print_raw_cr("# [ timer expired, abort... ]");
1305 // skip atexit/vm_exit/vm_abort hooks
1306 os::die();
1307 }
1308
1309 // Wake up 5 seconds later, the fatal handler may reset OnError or
1310 // ShowMessageBoxOnError when it is ready to abort.
1311 os::sleep(this, 5 * 1000, false);
1312 }
1313 }
1314
1315 if (_should_terminate) {
1316 // check for termination before posting the next tick
1317 break;
1318 }
1319
1320 PeriodicTask::real_time_tick(time_waited);
1321 }
1322
1323 // Signal that it is terminated
1324 {
1325 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1326 _watcher_thread = NULL;
1327 Terminator_lock->notify();
1328 }
1329 }
1330
1331 void WatcherThread::start() {
1332 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1333
1334 if (watcher_thread() == NULL && _startable) {
1335 _should_terminate = false;
1336 // Create the single instance of WatcherThread
1337 new WatcherThread();
1338 }
1339 }
1340
1341 void WatcherThread::make_startable() {
1342 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1343 _startable = true;
1344 }
1345
1346 void WatcherThread::stop() {
1347 {
1348 // Follow normal safepoint aware lock enter protocol since the
1349 // WatcherThread is stopped by another JavaThread.
1350 MutexLocker ml(PeriodicTask_lock);
1351 _should_terminate = true;
1352
1353 WatcherThread* watcher = watcher_thread();
1354 if (watcher != NULL) {
1355 // unpark the WatcherThread so it can see that it should terminate
1356 watcher->unpark();
1357 }
1358 }
1359
1360 MutexLocker mu(Terminator_lock);
1361
1362 while (watcher_thread() != NULL) {
1363 // This wait should make safepoint checks, wait without a timeout,
1364 // and wait as a suspend-equivalent condition.
1365 //
1366 // Note: If the FlatProfiler is running, then this thread is waiting
1367 // for the WatcherThread to terminate and the WatcherThread, via the
1368 // FlatProfiler task, is waiting for the external suspend request on
1369 // this thread to complete. wait_for_ext_suspend_completion() will
1370 // eventually timeout, but that takes time. Making this wait a
1371 // suspend-equivalent condition solves that timeout problem.
1372 //
1373 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1374 Mutex::_as_suspend_equivalent_flag);
1375 }
1376 }
1377
1378 void WatcherThread::unpark() {
1379 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1380 PeriodicTask_lock->notify();
1381 }
1382
1383 void WatcherThread::print_on(outputStream* st) const {
1384 st->print("\"%s\" ", name());
1385 Thread::print_on(st);
1386 st->cr();
1387 }
1388
1389 // ======= JavaThread ========
1390
1391 #if INCLUDE_JVMCI
1392
1393 jlong* JavaThread::_jvmci_old_thread_counters;
1394
1395 bool jvmci_counters_include(JavaThread* thread) {
1396 oop threadObj = thread->threadObj();
1397 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1398 }
1399
1400 void JavaThread::collect_counters(typeArrayOop array) {
1401 if (JVMCICounterSize > 0) {
1402 MutexLocker tl(Threads_lock);
1403 for (int i = 0; i < array->length(); i++) {
1404 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1405 }
1406 for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) {
1407 if (jvmci_counters_include(tp)) {
1408 for (int i = 0; i < array->length(); i++) {
1409 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1410 }
1411 }
1412 }
1413 }
1414 }
1415
1416 #endif // INCLUDE_JVMCI
1417
1418 // A JavaThread is a normal Java thread
1419
1420 void JavaThread::initialize() {
1421 // Initialize fields
1422
1423 set_saved_exception_pc(NULL);
1424 set_threadObj(NULL);
1425 _anchor.clear();
1426 set_entry_point(NULL);
1427 set_jni_functions(jni_functions());
1428 set_callee_target(NULL);
1429 set_vm_result(NULL);
1430 set_vm_result_2(NULL);
1431 set_vframe_array_head(NULL);
1432 set_vframe_array_last(NULL);
1433 set_deferred_locals(NULL);
1434 set_deopt_mark(NULL);
1435 set_deopt_nmethod(NULL);
1436 clear_must_deopt_id();
1437 set_monitor_chunks(NULL);
1438 set_next(NULL);
1439 set_thread_state(_thread_new);
1440 _terminated = _not_terminated;
1441 _privileged_stack_top = NULL;
1442 _array_for_gc = NULL;
1443 _suspend_equivalent = false;
1444 _in_deopt_handler = 0;
1445 _doing_unsafe_access = false;
1446 _stack_guard_state = stack_guard_unused;
1447 #if INCLUDE_JVMCI
1448 _pending_monitorenter = false;
1449 _pending_deoptimization = -1;
1450 _pending_failed_speculation = NULL;
1451 _pending_transfer_to_interpreter = false;
1452 _jvmci._alternate_call_target = NULL;
1453 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1454 if (JVMCICounterSize > 0) {
1455 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1456 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1457 } else {
1458 _jvmci_counters = NULL;
1459 }
1460 #endif // INCLUDE_JVMCI
1461 _reserved_stack_activation = NULL; // stack base not known yet
1462 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1463 _exception_pc = 0;
1464 _exception_handler_pc = 0;
1465 _is_method_handle_return = 0;
1466 _jvmti_thread_state= NULL;
1467 _should_post_on_exceptions_flag = JNI_FALSE;
1468 _jvmti_get_loaded_classes_closure = NULL;
1469 _interp_only_mode = 0;
1470 _special_runtime_exit_condition = _no_async_condition;
1471 _pending_async_exception = NULL;
1472 _thread_stat = NULL;
1473 _thread_stat = new ThreadStatistics();
1474 _blocked_on_compilation = false;
1475 _jni_active_critical = 0;
1476 _pending_jni_exception_check_fn = NULL;
1477 _do_not_unlock_if_synchronized = false;
1478 _cached_monitor_info = NULL;
1479 _parker = Parker::Allocate(this);
1480
1481 #ifndef PRODUCT
1482 _jmp_ring_index = 0;
1483 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1484 record_jump(NULL, NULL, NULL, 0);
1485 }
1486 #endif // PRODUCT
1487
1488 set_thread_profiler(NULL);
1489 if (FlatProfiler::is_active()) {
1490 // This is where we would decide to either give each thread it's own profiler
1491 // or use one global one from FlatProfiler,
1492 // or up to some count of the number of profiled threads, etc.
1493 ThreadProfiler* pp = new ThreadProfiler();
1494 pp->engage();
1495 set_thread_profiler(pp);
1496 }
1497
1498 // Setup safepoint state info for this thread
1499 ThreadSafepointState::create(this);
1500
1501 debug_only(_java_call_counter = 0);
1502
1503 // JVMTI PopFrame support
1504 _popframe_condition = popframe_inactive;
1505 _popframe_preserved_args = NULL;
1506 _popframe_preserved_args_size = 0;
1507 _frames_to_pop_failed_realloc = 0;
1508
1509 pd_initialize();
1510 }
1511
1512 #if INCLUDE_ALL_GCS
1513 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1514 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1515 #endif // INCLUDE_ALL_GCS
1516
1517 JavaThread::JavaThread(bool is_attaching_via_jni) :
1518 Thread()
1519 #if INCLUDE_ALL_GCS
1520 , _satb_mark_queue(&_satb_mark_queue_set),
1521 _dirty_card_queue(&_dirty_card_queue_set)
1522 #endif // INCLUDE_ALL_GCS
1523 {
1524 initialize();
1525 if (is_attaching_via_jni) {
1526 _jni_attach_state = _attaching_via_jni;
1527 } else {
1528 _jni_attach_state = _not_attaching_via_jni;
1529 }
1530 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1531 }
1532
1533 bool JavaThread::reguard_stack(address cur_sp) {
1534 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1535 && _stack_guard_state != stack_guard_reserved_disabled) {
1536 return true; // Stack already guarded or guard pages not needed.
1537 }
1538
1539 if (register_stack_overflow()) {
1540 // For those architectures which have separate register and
1541 // memory stacks, we must check the register stack to see if
1542 // it has overflowed.
1543 return false;
1544 }
1545
1546 // Java code never executes within the yellow zone: the latter is only
1547 // there to provoke an exception during stack banging. If java code
1548 // is executing there, either StackShadowPages should be larger, or
1549 // some exception code in c1, c2 or the interpreter isn't unwinding
1550 // when it should.
1551 guarantee(cur_sp > stack_reserved_zone_base(),
1552 "not enough space to reguard - increase StackShadowPages");
1553 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1554 enable_stack_yellow_reserved_zone();
1555 if (reserved_stack_activation() != stack_base()) {
1556 set_reserved_stack_activation(stack_base());
1557 }
1558 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1559 set_reserved_stack_activation(stack_base());
1560 enable_stack_reserved_zone();
1561 }
1562 return true;
1563 }
1564
1565 bool JavaThread::reguard_stack(void) {
1566 return reguard_stack(os::current_stack_pointer());
1567 }
1568
1569
1570 void JavaThread::block_if_vm_exited() {
1571 if (_terminated == _vm_exited) {
1572 // _vm_exited is set at safepoint, and Threads_lock is never released
1573 // we will block here forever
1574 Threads_lock->lock_without_safepoint_check();
1575 ShouldNotReachHere();
1576 }
1577 }
1578
1579
1580 // Remove this ifdef when C1 is ported to the compiler interface.
1581 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1582 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1583
1584 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1585 Thread()
1586 #if INCLUDE_ALL_GCS
1587 , _satb_mark_queue(&_satb_mark_queue_set),
1588 _dirty_card_queue(&_dirty_card_queue_set)
1589 #endif // INCLUDE_ALL_GCS
1590 {
1591 initialize();
1592 _jni_attach_state = _not_attaching_via_jni;
1593 set_entry_point(entry_point);
1594 // Create the native thread itself.
1595 // %note runtime_23
1596 os::ThreadType thr_type = os::java_thread;
1597 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1598 os::java_thread;
1599 os::create_thread(this, thr_type, stack_sz);
1600 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1601 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1602 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1603 // the exception consists of creating the exception object & initializing it, initialization
1604 // will leave the VM via a JavaCall and then all locks must be unlocked).
1605 //
1606 // The thread is still suspended when we reach here. Thread must be explicit started
1607 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1608 // by calling Threads:add. The reason why this is not done here, is because the thread
1609 // object must be fully initialized (take a look at JVM_Start)
1610 }
1611
1612 JavaThread::~JavaThread() {
1613
1614 // JSR166 -- return the parker to the free list
1615 Parker::Release(_parker);
1616 _parker = NULL;
1617
1618 // Free any remaining previous UnrollBlock
1619 vframeArray* old_array = vframe_array_last();
1620
1621 if (old_array != NULL) {
1622 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1623 old_array->set_unroll_block(NULL);
1624 delete old_info;
1625 delete old_array;
1626 }
1627
1628 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1629 if (deferred != NULL) {
1630 // This can only happen if thread is destroyed before deoptimization occurs.
1631 assert(deferred->length() != 0, "empty array!");
1632 do {
1633 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1634 deferred->remove_at(0);
1635 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1636 delete dlv;
1637 } while (deferred->length() != 0);
1638 delete deferred;
1639 }
1640
1641 // All Java related clean up happens in exit
1642 ThreadSafepointState::destroy(this);
1643 if (_thread_profiler != NULL) delete _thread_profiler;
1644 if (_thread_stat != NULL) delete _thread_stat;
1645
1646 #if INCLUDE_JVMCI
1647 if (JVMCICounterSize > 0) {
1648 if (jvmci_counters_include(this)) {
1649 for (int i = 0; i < JVMCICounterSize; i++) {
1650 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1651 }
1652 }
1653 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1654 }
1655 #endif // INCLUDE_JVMCI
1656 }
1657
1658
1659 // The first routine called by a new Java thread
1660 void JavaThread::run() {
1661 // initialize thread-local alloc buffer related fields
1662 this->initialize_tlab();
1663
1664 // used to test validity of stack trace backs
1665 this->record_base_of_stack_pointer();
1666
1667 // Record real stack base and size.
1668 this->record_stack_base_and_size();
1669
1670 this->create_stack_guard_pages();
1671
1672 this->cache_global_variables();
1673
1674 // Thread is now sufficient initialized to be handled by the safepoint code as being
1675 // in the VM. Change thread state from _thread_new to _thread_in_vm
1676 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1677
1678 assert(JavaThread::current() == this, "sanity check");
1679 assert(!Thread::current()->owns_locks(), "sanity check");
1680
1681 DTRACE_THREAD_PROBE(start, this);
1682
1683 // This operation might block. We call that after all safepoint checks for a new thread has
1684 // been completed.
1685 this->set_active_handles(JNIHandleBlock::allocate_block());
1686
1687 if (JvmtiExport::should_post_thread_life()) {
1688 JvmtiExport::post_thread_start(this);
1689 }
1690
1691 EventThreadStart event;
1692 if (event.should_commit()) {
1693 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1694 event.commit();
1695 }
1696
1697 // We call another function to do the rest so we are sure that the stack addresses used
1698 // from there will be lower than the stack base just computed
1699 thread_main_inner();
1700
1701 // Note, thread is no longer valid at this point!
1702 }
1703
1704
1705 void JavaThread::thread_main_inner() {
1706 assert(JavaThread::current() == this, "sanity check");
1707 assert(this->threadObj() != NULL, "just checking");
1708
1709 // Execute thread entry point unless this thread has a pending exception
1710 // or has been stopped before starting.
1711 // Note: Due to JVM_StopThread we can have pending exceptions already!
1712 if (!this->has_pending_exception() &&
1713 !java_lang_Thread::is_stillborn(this->threadObj())) {
1714 {
1715 ResourceMark rm(this);
1716 this->set_native_thread_name(this->get_thread_name());
1717 }
1718 HandleMark hm(this);
1719 this->entry_point()(this, this);
1720 }
1721
1722 DTRACE_THREAD_PROBE(stop, this);
1723
1724 this->exit(false);
1725 delete this;
1726 }
1727
1728
1729 static void ensure_join(JavaThread* thread) {
1730 // We do not need to grap the Threads_lock, since we are operating on ourself.
1731 Handle threadObj(thread, thread->threadObj());
1732 assert(threadObj.not_null(), "java thread object must exist");
1733 ObjectLocker lock(threadObj, thread);
1734 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1735 thread->clear_pending_exception();
1736 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1737 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1738 // Clear the native thread instance - this makes isAlive return false and allows the join()
1739 // to complete once we've done the notify_all below
1740 java_lang_Thread::set_thread(threadObj(), NULL);
1741 lock.notify_all(thread);
1742 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1743 thread->clear_pending_exception();
1744 }
1745
1746
1747 // For any new cleanup additions, please check to see if they need to be applied to
1748 // cleanup_failed_attach_current_thread as well.
1749 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1750 assert(this == JavaThread::current(), "thread consistency check");
1751
1752 HandleMark hm(this);
1753 Handle uncaught_exception(this, this->pending_exception());
1754 this->clear_pending_exception();
1755 Handle threadObj(this, this->threadObj());
1756 assert(threadObj.not_null(), "Java thread object should be created");
1757
1758 if (get_thread_profiler() != NULL) {
1759 get_thread_profiler()->disengage();
1760 ResourceMark rm;
1761 get_thread_profiler()->print(get_thread_name());
1762 }
1763
1764
1765 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1766 {
1767 EXCEPTION_MARK;
1768
1769 CLEAR_PENDING_EXCEPTION;
1770 }
1771 if (!destroy_vm) {
1772 if (uncaught_exception.not_null()) {
1773 EXCEPTION_MARK;
1774 // Call method Thread.dispatchUncaughtException().
1775 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1776 JavaValue result(T_VOID);
1777 JavaCalls::call_virtual(&result,
1778 threadObj, thread_klass,
1779 vmSymbols::dispatchUncaughtException_name(),
1780 vmSymbols::throwable_void_signature(),
1781 uncaught_exception,
1782 THREAD);
1783 if (HAS_PENDING_EXCEPTION) {
1784 ResourceMark rm(this);
1785 jio_fprintf(defaultStream::error_stream(),
1786 "\nException: %s thrown from the UncaughtExceptionHandler"
1787 " in thread \"%s\"\n",
1788 pending_exception()->klass()->external_name(),
1789 get_thread_name());
1790 CLEAR_PENDING_EXCEPTION;
1791 }
1792 }
1793
1794 // Called before the java thread exit since we want to read info
1795 // from java_lang_Thread object
1796 EventThreadEnd event;
1797 if (event.should_commit()) {
1798 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1799 event.commit();
1800 }
1801
1802 // Call after last event on thread
1803 EVENT_THREAD_EXIT(this);
1804
1805 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1806 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1807 // is deprecated anyhow.
1808 if (!is_Compiler_thread()) {
1809 int count = 3;
1810 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1811 EXCEPTION_MARK;
1812 JavaValue result(T_VOID);
1813 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1814 JavaCalls::call_virtual(&result,
1815 threadObj, thread_klass,
1816 vmSymbols::exit_method_name(),
1817 vmSymbols::void_method_signature(),
1818 THREAD);
1819 CLEAR_PENDING_EXCEPTION;
1820 }
1821 }
1822 // notify JVMTI
1823 if (JvmtiExport::should_post_thread_life()) {
1824 JvmtiExport::post_thread_end(this);
1825 }
1826
1827 // We have notified the agents that we are exiting, before we go on,
1828 // we must check for a pending external suspend request and honor it
1829 // in order to not surprise the thread that made the suspend request.
1830 while (true) {
1831 {
1832 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1833 if (!is_external_suspend()) {
1834 set_terminated(_thread_exiting);
1835 ThreadService::current_thread_exiting(this);
1836 break;
1837 }
1838 // Implied else:
1839 // Things get a little tricky here. We have a pending external
1840 // suspend request, but we are holding the SR_lock so we
1841 // can't just self-suspend. So we temporarily drop the lock
1842 // and then self-suspend.
1843 }
1844
1845 ThreadBlockInVM tbivm(this);
1846 java_suspend_self();
1847
1848 // We're done with this suspend request, but we have to loop around
1849 // and check again. Eventually we will get SR_lock without a pending
1850 // external suspend request and will be able to mark ourselves as
1851 // exiting.
1852 }
1853 // no more external suspends are allowed at this point
1854 } else {
1855 // before_exit() has already posted JVMTI THREAD_END events
1856 }
1857
1858 // Notify waiters on thread object. This has to be done after exit() is called
1859 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1860 // group should have the destroyed bit set before waiters are notified).
1861 ensure_join(this);
1862 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1863
1864 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1865 // held by this thread must be released. The spec does not distinguish
1866 // between JNI-acquired and regular Java monitors. We can only see
1867 // regular Java monitors here if monitor enter-exit matching is broken.
1868 //
1869 // Optionally release any monitors for regular JavaThread exits. This
1870 // is provided as a work around for any bugs in monitor enter-exit
1871 // matching. This can be expensive so it is not enabled by default.
1872 //
1873 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1874 // ObjectSynchronizer::release_monitors_owned_by_thread().
1875 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
1876 // Sanity check even though JNI DetachCurrentThread() would have
1877 // returned JNI_ERR if there was a Java frame. JavaThread exit
1878 // should be done executing Java code by the time we get here.
1879 assert(!this->has_last_Java_frame(),
1880 "should not have a Java frame when detaching or exiting");
1881 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1882 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1883 }
1884
1885 // These things needs to be done while we are still a Java Thread. Make sure that thread
1886 // is in a consistent state, in case GC happens
1887 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1888
1889 if (active_handles() != NULL) {
1890 JNIHandleBlock* block = active_handles();
1891 set_active_handles(NULL);
1892 JNIHandleBlock::release_block(block);
1893 }
1894
1895 if (free_handle_block() != NULL) {
1896 JNIHandleBlock* block = free_handle_block();
1897 set_free_handle_block(NULL);
1898 JNIHandleBlock::release_block(block);
1899 }
1900
1901 // These have to be removed while this is still a valid thread.
1902 remove_stack_guard_pages();
1903
1904 if (UseTLAB) {
1905 tlab().make_parsable(true); // retire TLAB
1906 }
1907
1908 if (JvmtiEnv::environments_might_exist()) {
1909 JvmtiExport::cleanup_thread(this);
1910 }
1911
1912 // We must flush any deferred card marks before removing a thread from
1913 // the list of active threads.
1914 Universe::heap()->flush_deferred_store_barrier(this);
1915 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1916
1917 #if INCLUDE_ALL_GCS
1918 // We must flush the G1-related buffers before removing a thread
1919 // from the list of active threads. We must do this after any deferred
1920 // card marks have been flushed (above) so that any entries that are
1921 // added to the thread's dirty card queue as a result are not lost.
1922 if (UseG1GC) {
1923 flush_barrier_queues();
1924 }
1925 #endif // INCLUDE_ALL_GCS
1926
1927 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1928 Threads::remove(this);
1929 }
1930
1931 #if INCLUDE_ALL_GCS
1932 // Flush G1-related queues.
1933 void JavaThread::flush_barrier_queues() {
1934 satb_mark_queue().flush();
1935 dirty_card_queue().flush();
1936 }
1937
1938 void JavaThread::initialize_queues() {
1939 assert(!SafepointSynchronize::is_at_safepoint(),
1940 "we should not be at a safepoint");
1941
1942 SATBMarkQueue& satb_queue = satb_mark_queue();
1943 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1944 // The SATB queue should have been constructed with its active
1945 // field set to false.
1946 assert(!satb_queue.is_active(), "SATB queue should not be active");
1947 assert(satb_queue.is_empty(), "SATB queue should be empty");
1948 // If we are creating the thread during a marking cycle, we should
1949 // set the active field of the SATB queue to true.
1950 if (satb_queue_set.is_active()) {
1951 satb_queue.set_active(true);
1952 }
1953
1954 DirtyCardQueue& dirty_queue = dirty_card_queue();
1955 // The dirty card queue should have been constructed with its
1956 // active field set to true.
1957 assert(dirty_queue.is_active(), "dirty card queue should be active");
1958 }
1959 #endif // INCLUDE_ALL_GCS
1960
1961 void JavaThread::cleanup_failed_attach_current_thread() {
1962 if (get_thread_profiler() != NULL) {
1963 get_thread_profiler()->disengage();
1964 ResourceMark rm;
1965 get_thread_profiler()->print(get_thread_name());
1966 }
1967
1968 if (active_handles() != NULL) {
1969 JNIHandleBlock* block = active_handles();
1970 set_active_handles(NULL);
1971 JNIHandleBlock::release_block(block);
1972 }
1973
1974 if (free_handle_block() != NULL) {
1975 JNIHandleBlock* block = free_handle_block();
1976 set_free_handle_block(NULL);
1977 JNIHandleBlock::release_block(block);
1978 }
1979
1980 // These have to be removed while this is still a valid thread.
1981 remove_stack_guard_pages();
1982
1983 if (UseTLAB) {
1984 tlab().make_parsable(true); // retire TLAB, if any
1985 }
1986
1987 #if INCLUDE_ALL_GCS
1988 if (UseG1GC) {
1989 flush_barrier_queues();
1990 }
1991 #endif // INCLUDE_ALL_GCS
1992
1993 Threads::remove(this);
1994 delete this;
1995 }
1996
1997
1998
1999
2000 JavaThread* JavaThread::active() {
2001 Thread* thread = Thread::current();
2002 if (thread->is_Java_thread()) {
2003 return (JavaThread*) thread;
2004 } else {
2005 assert(thread->is_VM_thread(), "this must be a vm thread");
2006 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2007 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2008 assert(ret->is_Java_thread(), "must be a Java thread");
2009 return ret;
2010 }
2011 }
2012
2013 bool JavaThread::is_lock_owned(address adr) const {
2014 if (Thread::is_lock_owned(adr)) return true;
2015
2016 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2017 if (chunk->contains(adr)) return true;
2018 }
2019
2020 return false;
2021 }
2022
2023
2024 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2025 chunk->set_next(monitor_chunks());
2026 set_monitor_chunks(chunk);
2027 }
2028
2029 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2030 guarantee(monitor_chunks() != NULL, "must be non empty");
2031 if (monitor_chunks() == chunk) {
2032 set_monitor_chunks(chunk->next());
2033 } else {
2034 MonitorChunk* prev = monitor_chunks();
2035 while (prev->next() != chunk) prev = prev->next();
2036 prev->set_next(chunk->next());
2037 }
2038 }
2039
2040 // JVM support.
2041
2042 // Note: this function shouldn't block if it's called in
2043 // _thread_in_native_trans state (such as from
2044 // check_special_condition_for_native_trans()).
2045 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2046
2047 if (has_last_Java_frame() && has_async_condition()) {
2048 // If we are at a polling page safepoint (not a poll return)
2049 // then we must defer async exception because live registers
2050 // will be clobbered by the exception path. Poll return is
2051 // ok because the call we a returning from already collides
2052 // with exception handling registers and so there is no issue.
2053 // (The exception handling path kills call result registers but
2054 // this is ok since the exception kills the result anyway).
2055
2056 if (is_at_poll_safepoint()) {
2057 // if the code we are returning to has deoptimized we must defer
2058 // the exception otherwise live registers get clobbered on the
2059 // exception path before deoptimization is able to retrieve them.
2060 //
2061 RegisterMap map(this, false);
2062 frame caller_fr = last_frame().sender(&map);
2063 assert(caller_fr.is_compiled_frame(), "what?");
2064 if (caller_fr.is_deoptimized_frame()) {
2065 log_info(exceptions)("deferred async exception at compiled safepoint");
2066 return;
2067 }
2068 }
2069 }
2070
2071 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2072 if (condition == _no_async_condition) {
2073 // Conditions have changed since has_special_runtime_exit_condition()
2074 // was called:
2075 // - if we were here only because of an external suspend request,
2076 // then that was taken care of above (or cancelled) so we are done
2077 // - if we were here because of another async request, then it has
2078 // been cleared between the has_special_runtime_exit_condition()
2079 // and now so again we are done
2080 return;
2081 }
2082
2083 // Check for pending async. exception
2084 if (_pending_async_exception != NULL) {
2085 // Only overwrite an already pending exception, if it is not a threadDeath.
2086 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2087
2088 // We cannot call Exceptions::_throw(...) here because we cannot block
2089 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2090
2091 if (log_is_enabled(Info, exceptions)) {
2092 ResourceMark rm;
2093 outputStream* logstream = LogHandle(exceptions)::info_stream();
2094 logstream->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2095 if (has_last_Java_frame()) {
2096 frame f = last_frame();
2097 logstream->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2098 }
2099 logstream->print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2100 }
2101 _pending_async_exception = NULL;
2102 clear_has_async_exception();
2103 }
2104 }
2105
2106 if (check_unsafe_error &&
2107 condition == _async_unsafe_access_error && !has_pending_exception()) {
2108 condition = _no_async_condition; // done
2109 switch (thread_state()) {
2110 case _thread_in_vm: {
2111 JavaThread* THREAD = this;
2112 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2113 }
2114 case _thread_in_native: {
2115 ThreadInVMfromNative tiv(this);
2116 JavaThread* THREAD = this;
2117 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2118 }
2119 case _thread_in_Java: {
2120 ThreadInVMfromJava tiv(this);
2121 JavaThread* THREAD = this;
2122 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2123 }
2124 default:
2125 ShouldNotReachHere();
2126 }
2127 }
2128
2129 assert(condition == _no_async_condition || has_pending_exception() ||
2130 (!check_unsafe_error && condition == _async_unsafe_access_error),
2131 "must have handled the async condition, if no exception");
2132 }
2133
2134 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2135 //
2136 // Check for pending external suspend. Internal suspend requests do
2137 // not use handle_special_runtime_exit_condition().
2138 // If JNIEnv proxies are allowed, don't self-suspend if the target
2139 // thread is not the current thread. In older versions of jdbx, jdbx
2140 // threads could call into the VM with another thread's JNIEnv so we
2141 // can be here operating on behalf of a suspended thread (4432884).
2142 bool do_self_suspend = is_external_suspend_with_lock();
2143 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2144 //
2145 // Because thread is external suspended the safepoint code will count
2146 // thread as at a safepoint. This can be odd because we can be here
2147 // as _thread_in_Java which would normally transition to _thread_blocked
2148 // at a safepoint. We would like to mark the thread as _thread_blocked
2149 // before calling java_suspend_self like all other callers of it but
2150 // we must then observe proper safepoint protocol. (We can't leave
2151 // _thread_blocked with a safepoint in progress). However we can be
2152 // here as _thread_in_native_trans so we can't use a normal transition
2153 // constructor/destructor pair because they assert on that type of
2154 // transition. We could do something like:
2155 //
2156 // JavaThreadState state = thread_state();
2157 // set_thread_state(_thread_in_vm);
2158 // {
2159 // ThreadBlockInVM tbivm(this);
2160 // java_suspend_self()
2161 // }
2162 // set_thread_state(_thread_in_vm_trans);
2163 // if (safepoint) block;
2164 // set_thread_state(state);
2165 //
2166 // but that is pretty messy. Instead we just go with the way the
2167 // code has worked before and note that this is the only path to
2168 // java_suspend_self that doesn't put the thread in _thread_blocked
2169 // mode.
2170
2171 frame_anchor()->make_walkable(this);
2172 java_suspend_self();
2173
2174 // We might be here for reasons in addition to the self-suspend request
2175 // so check for other async requests.
2176 }
2177
2178 if (check_asyncs) {
2179 check_and_handle_async_exceptions();
2180 }
2181 }
2182
2183 void JavaThread::send_thread_stop(oop java_throwable) {
2184 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2185 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2186 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2187
2188 // Do not throw asynchronous exceptions against the compiler thread
2189 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2190 if (!can_call_java()) return;
2191
2192 {
2193 // Actually throw the Throwable against the target Thread - however
2194 // only if there is no thread death exception installed already.
2195 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2196 // If the topmost frame is a runtime stub, then we are calling into
2197 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2198 // must deoptimize the caller before continuing, as the compiled exception handler table
2199 // may not be valid
2200 if (has_last_Java_frame()) {
2201 frame f = last_frame();
2202 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2203 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2204 RegisterMap reg_map(this, UseBiasedLocking);
2205 frame compiled_frame = f.sender(®_map);
2206 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2207 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2208 }
2209 }
2210 }
2211
2212 // Set async. pending exception in thread.
2213 set_pending_async_exception(java_throwable);
2214
2215 if (log_is_enabled(Info, exceptions)) {
2216 ResourceMark rm;
2217 log_info(exceptions)("Pending Async. exception installed of type: %s",
2218 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2219 }
2220 // for AbortVMOnException flag
2221 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2222 }
2223 }
2224
2225
2226 // Interrupt thread so it will wake up from a potential wait()
2227 Thread::interrupt(this);
2228 }
2229
2230 // External suspension mechanism.
2231 //
2232 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2233 // to any VM_locks and it is at a transition
2234 // Self-suspension will happen on the transition out of the vm.
2235 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2236 //
2237 // Guarantees on return:
2238 // + Target thread will not execute any new bytecode (that's why we need to
2239 // force a safepoint)
2240 // + Target thread will not enter any new monitors
2241 //
2242 void JavaThread::java_suspend() {
2243 { MutexLocker mu(Threads_lock);
2244 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2245 return;
2246 }
2247 }
2248
2249 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2250 if (!is_external_suspend()) {
2251 // a racing resume has cancelled us; bail out now
2252 return;
2253 }
2254
2255 // suspend is done
2256 uint32_t debug_bits = 0;
2257 // Warning: is_ext_suspend_completed() may temporarily drop the
2258 // SR_lock to allow the thread to reach a stable thread state if
2259 // it is currently in a transient thread state.
2260 if (is_ext_suspend_completed(false /* !called_by_wait */,
2261 SuspendRetryDelay, &debug_bits)) {
2262 return;
2263 }
2264 }
2265
2266 VM_ForceSafepoint vm_suspend;
2267 VMThread::execute(&vm_suspend);
2268 }
2269
2270 // Part II of external suspension.
2271 // A JavaThread self suspends when it detects a pending external suspend
2272 // request. This is usually on transitions. It is also done in places
2273 // where continuing to the next transition would surprise the caller,
2274 // e.g., monitor entry.
2275 //
2276 // Returns the number of times that the thread self-suspended.
2277 //
2278 // Note: DO NOT call java_suspend_self() when you just want to block current
2279 // thread. java_suspend_self() is the second stage of cooperative
2280 // suspension for external suspend requests and should only be used
2281 // to complete an external suspend request.
2282 //
2283 int JavaThread::java_suspend_self() {
2284 int ret = 0;
2285
2286 // we are in the process of exiting so don't suspend
2287 if (is_exiting()) {
2288 clear_external_suspend();
2289 return ret;
2290 }
2291
2292 assert(_anchor.walkable() ||
2293 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2294 "must have walkable stack");
2295
2296 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2297
2298 assert(!this->is_ext_suspended(),
2299 "a thread trying to self-suspend should not already be suspended");
2300
2301 if (this->is_suspend_equivalent()) {
2302 // If we are self-suspending as a result of the lifting of a
2303 // suspend equivalent condition, then the suspend_equivalent
2304 // flag is not cleared until we set the ext_suspended flag so
2305 // that wait_for_ext_suspend_completion() returns consistent
2306 // results.
2307 this->clear_suspend_equivalent();
2308 }
2309
2310 // A racing resume may have cancelled us before we grabbed SR_lock
2311 // above. Or another external suspend request could be waiting for us
2312 // by the time we return from SR_lock()->wait(). The thread
2313 // that requested the suspension may already be trying to walk our
2314 // stack and if we return now, we can change the stack out from under
2315 // it. This would be a "bad thing (TM)" and cause the stack walker
2316 // to crash. We stay self-suspended until there are no more pending
2317 // external suspend requests.
2318 while (is_external_suspend()) {
2319 ret++;
2320 this->set_ext_suspended();
2321
2322 // _ext_suspended flag is cleared by java_resume()
2323 while (is_ext_suspended()) {
2324 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2325 }
2326 }
2327
2328 return ret;
2329 }
2330
2331 #ifdef ASSERT
2332 // verify the JavaThread has not yet been published in the Threads::list, and
2333 // hence doesn't need protection from concurrent access at this stage
2334 void JavaThread::verify_not_published() {
2335 if (!Threads_lock->owned_by_self()) {
2336 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2337 assert(!Threads::includes(this),
2338 "java thread shouldn't have been published yet!");
2339 } else {
2340 assert(!Threads::includes(this),
2341 "java thread shouldn't have been published yet!");
2342 }
2343 }
2344 #endif
2345
2346 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2347 // progress or when _suspend_flags is non-zero.
2348 // Current thread needs to self-suspend if there is a suspend request and/or
2349 // block if a safepoint is in progress.
2350 // Async exception ISN'T checked.
2351 // Note only the ThreadInVMfromNative transition can call this function
2352 // directly and when thread state is _thread_in_native_trans
2353 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2354 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2355
2356 JavaThread *curJT = JavaThread::current();
2357 bool do_self_suspend = thread->is_external_suspend();
2358
2359 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2360
2361 // If JNIEnv proxies are allowed, don't self-suspend if the target
2362 // thread is not the current thread. In older versions of jdbx, jdbx
2363 // threads could call into the VM with another thread's JNIEnv so we
2364 // can be here operating on behalf of a suspended thread (4432884).
2365 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2366 JavaThreadState state = thread->thread_state();
2367
2368 // We mark this thread_blocked state as a suspend-equivalent so
2369 // that a caller to is_ext_suspend_completed() won't be confused.
2370 // The suspend-equivalent state is cleared by java_suspend_self().
2371 thread->set_suspend_equivalent();
2372
2373 // If the safepoint code sees the _thread_in_native_trans state, it will
2374 // wait until the thread changes to other thread state. There is no
2375 // guarantee on how soon we can obtain the SR_lock and complete the
2376 // self-suspend request. It would be a bad idea to let safepoint wait for
2377 // too long. Temporarily change the state to _thread_blocked to
2378 // let the VM thread know that this thread is ready for GC. The problem
2379 // of changing thread state is that safepoint could happen just after
2380 // java_suspend_self() returns after being resumed, and VM thread will
2381 // see the _thread_blocked state. We must check for safepoint
2382 // after restoring the state and make sure we won't leave while a safepoint
2383 // is in progress.
2384 thread->set_thread_state(_thread_blocked);
2385 thread->java_suspend_self();
2386 thread->set_thread_state(state);
2387 // Make sure new state is seen by VM thread
2388 if (os::is_MP()) {
2389 if (UseMembar) {
2390 // Force a fence between the write above and read below
2391 OrderAccess::fence();
2392 } else {
2393 // Must use this rather than serialization page in particular on Windows
2394 InterfaceSupport::serialize_memory(thread);
2395 }
2396 }
2397 }
2398
2399 if (SafepointSynchronize::do_call_back()) {
2400 // If we are safepointing, then block the caller which may not be
2401 // the same as the target thread (see above).
2402 SafepointSynchronize::block(curJT);
2403 }
2404
2405 if (thread->is_deopt_suspend()) {
2406 thread->clear_deopt_suspend();
2407 RegisterMap map(thread, false);
2408 frame f = thread->last_frame();
2409 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2410 f = f.sender(&map);
2411 }
2412 if (f.id() == thread->must_deopt_id()) {
2413 thread->clear_must_deopt_id();
2414 f.deoptimize(thread);
2415 } else {
2416 fatal("missed deoptimization!");
2417 }
2418 }
2419 }
2420
2421 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2422 // progress or when _suspend_flags is non-zero.
2423 // Current thread needs to self-suspend if there is a suspend request and/or
2424 // block if a safepoint is in progress.
2425 // Also check for pending async exception (not including unsafe access error).
2426 // Note only the native==>VM/Java barriers can call this function and when
2427 // thread state is _thread_in_native_trans.
2428 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2429 check_safepoint_and_suspend_for_native_trans(thread);
2430
2431 if (thread->has_async_exception()) {
2432 // We are in _thread_in_native_trans state, don't handle unsafe
2433 // access error since that may block.
2434 thread->check_and_handle_async_exceptions(false);
2435 }
2436 }
2437
2438 // This is a variant of the normal
2439 // check_special_condition_for_native_trans with slightly different
2440 // semantics for use by critical native wrappers. It does all the
2441 // normal checks but also performs the transition back into
2442 // thread_in_Java state. This is required so that critical natives
2443 // can potentially block and perform a GC if they are the last thread
2444 // exiting the GCLocker.
2445 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2446 check_special_condition_for_native_trans(thread);
2447
2448 // Finish the transition
2449 thread->set_thread_state(_thread_in_Java);
2450
2451 if (thread->do_critical_native_unlock()) {
2452 ThreadInVMfromJavaNoAsyncException tiv(thread);
2453 GCLocker::unlock_critical(thread);
2454 thread->clear_critical_native_unlock();
2455 }
2456 }
2457
2458 // We need to guarantee the Threads_lock here, since resumes are not
2459 // allowed during safepoint synchronization
2460 // Can only resume from an external suspension
2461 void JavaThread::java_resume() {
2462 assert_locked_or_safepoint(Threads_lock);
2463
2464 // Sanity check: thread is gone, has started exiting or the thread
2465 // was not externally suspended.
2466 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2467 return;
2468 }
2469
2470 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2471
2472 clear_external_suspend();
2473
2474 if (is_ext_suspended()) {
2475 clear_ext_suspended();
2476 SR_lock()->notify_all();
2477 }
2478 }
2479
2480 size_t JavaThread::_stack_red_zone_size = 0;
2481 size_t JavaThread::_stack_yellow_zone_size = 0;
2482 size_t JavaThread::_stack_reserved_zone_size = 0;
2483 size_t JavaThread::_stack_shadow_zone_size = 0;
2484
2485 void JavaThread::create_stack_guard_pages() {
2486 if (!os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) { return; }
2487 address low_addr = stack_end();
2488 size_t len = stack_guard_zone_size();
2489
2490 int allocate = os::allocate_stack_guard_pages();
2491 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2492
2493 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2494 warning("Attempt to allocate stack guard pages failed.");
2495 return;
2496 }
2497
2498 if (os::guard_memory((char *) low_addr, len)) {
2499 _stack_guard_state = stack_guard_enabled;
2500 } else {
2501 warning("Attempt to protect stack guard pages failed.");
2502 if (os::uncommit_memory((char *) low_addr, len)) {
2503 warning("Attempt to deallocate stack guard pages failed.");
2504 }
2505 }
2506 }
2507
2508 void JavaThread::remove_stack_guard_pages() {
2509 assert(Thread::current() == this, "from different thread");
2510 if (_stack_guard_state == stack_guard_unused) return;
2511 address low_addr = stack_end();
2512 size_t len = stack_guard_zone_size();
2513
2514 if (os::allocate_stack_guard_pages()) {
2515 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2516 _stack_guard_state = stack_guard_unused;
2517 } else {
2518 warning("Attempt to deallocate stack guard pages failed.");
2519 }
2520 } else {
2521 if (_stack_guard_state == stack_guard_unused) return;
2522 if (os::unguard_memory((char *) low_addr, len)) {
2523 _stack_guard_state = stack_guard_unused;
2524 } else {
2525 warning("Attempt to unprotect stack guard pages failed.");
2526 }
2527 }
2528 }
2529
2530 void JavaThread::enable_stack_reserved_zone() {
2531 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2532 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2533
2534 // The base notation is from the stack's point of view, growing downward.
2535 // We need to adjust it to work correctly with guard_memory()
2536 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2537
2538 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2539 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2540
2541 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2542 _stack_guard_state = stack_guard_enabled;
2543 } else {
2544 warning("Attempt to guard stack reserved zone failed.");
2545 }
2546 enable_register_stack_guard();
2547 }
2548
2549 void JavaThread::disable_stack_reserved_zone() {
2550 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2551 assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled");
2552
2553 // Simply return if called for a thread that does not use guard pages.
2554 if (_stack_guard_state == stack_guard_unused) return;
2555
2556 // The base notation is from the stack's point of view, growing downward.
2557 // We need to adjust it to work correctly with guard_memory()
2558 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2559
2560 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2561 _stack_guard_state = stack_guard_reserved_disabled;
2562 } else {
2563 warning("Attempt to unguard stack reserved zone failed.");
2564 }
2565 disable_register_stack_guard();
2566 }
2567
2568 void JavaThread::enable_stack_yellow_reserved_zone() {
2569 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2570 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2571
2572 // The base notation is from the stacks point of view, growing downward.
2573 // We need to adjust it to work correctly with guard_memory()
2574 address base = stack_red_zone_base();
2575
2576 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2577 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2578
2579 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2580 _stack_guard_state = stack_guard_enabled;
2581 } else {
2582 warning("Attempt to guard stack yellow zone failed.");
2583 }
2584 enable_register_stack_guard();
2585 }
2586
2587 void JavaThread::disable_stack_yellow_reserved_zone() {
2588 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2589 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2590
2591 // Simply return if called for a thread that does not use guard pages.
2592 if (_stack_guard_state == stack_guard_unused) return;
2593
2594 // The base notation is from the stacks point of view, growing downward.
2595 // We need to adjust it to work correctly with guard_memory()
2596 address base = stack_red_zone_base();
2597
2598 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2599 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2600 } else {
2601 warning("Attempt to unguard stack yellow zone failed.");
2602 }
2603 disable_register_stack_guard();
2604 }
2605
2606 void JavaThread::enable_stack_red_zone() {
2607 // The base notation is from the stacks point of view, growing downward.
2608 // We need to adjust it to work correctly with guard_memory()
2609 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2610 address base = stack_red_zone_base() - stack_red_zone_size();
2611
2612 guarantee(base < stack_base(), "Error calculating stack red zone");
2613 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2614
2615 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2616 warning("Attempt to guard stack red zone failed.");
2617 }
2618 }
2619
2620 void JavaThread::disable_stack_red_zone() {
2621 // The base notation is from the stacks point of view, growing downward.
2622 // We need to adjust it to work correctly with guard_memory()
2623 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2624 address base = stack_red_zone_base() - stack_red_zone_size();
2625 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2626 warning("Attempt to unguard stack red zone failed.");
2627 }
2628 }
2629
2630 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2631 // ignore is there is no stack
2632 if (!has_last_Java_frame()) return;
2633 // traverse the stack frames. Starts from top frame.
2634 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2635 frame* fr = fst.current();
2636 f(fr, fst.register_map());
2637 }
2638 }
2639
2640
2641 #ifndef PRODUCT
2642 // Deoptimization
2643 // Function for testing deoptimization
2644 void JavaThread::deoptimize() {
2645 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2646 StackFrameStream fst(this, UseBiasedLocking);
2647 bool deopt = false; // Dump stack only if a deopt actually happens.
2648 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2649 // Iterate over all frames in the thread and deoptimize
2650 for (; !fst.is_done(); fst.next()) {
2651 if (fst.current()->can_be_deoptimized()) {
2652
2653 if (only_at) {
2654 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2655 // consists of comma or carriage return separated numbers so
2656 // search for the current bci in that string.
2657 address pc = fst.current()->pc();
2658 nmethod* nm = (nmethod*) fst.current()->cb();
2659 ScopeDesc* sd = nm->scope_desc_at(pc);
2660 char buffer[8];
2661 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2662 size_t len = strlen(buffer);
2663 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2664 while (found != NULL) {
2665 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2666 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2667 // Check that the bci found is bracketed by terminators.
2668 break;
2669 }
2670 found = strstr(found + 1, buffer);
2671 }
2672 if (!found) {
2673 continue;
2674 }
2675 }
2676
2677 if (DebugDeoptimization && !deopt) {
2678 deopt = true; // One-time only print before deopt
2679 tty->print_cr("[BEFORE Deoptimization]");
2680 trace_frames();
2681 trace_stack();
2682 }
2683 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2684 }
2685 }
2686
2687 if (DebugDeoptimization && deopt) {
2688 tty->print_cr("[AFTER Deoptimization]");
2689 trace_frames();
2690 }
2691 }
2692
2693
2694 // Make zombies
2695 void JavaThread::make_zombies() {
2696 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2697 if (fst.current()->can_be_deoptimized()) {
2698 // it is a Java nmethod
2699 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2700 nm->make_not_entrant();
2701 }
2702 }
2703 }
2704 #endif // PRODUCT
2705
2706
2707 void JavaThread::deoptimized_wrt_marked_nmethods() {
2708 if (!has_last_Java_frame()) return;
2709 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2710 StackFrameStream fst(this, UseBiasedLocking);
2711 for (; !fst.is_done(); fst.next()) {
2712 if (fst.current()->should_be_deoptimized()) {
2713 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2714 }
2715 }
2716 }
2717
2718
2719 // If the caller is a NamedThread, then remember, in the current scope,
2720 // the given JavaThread in its _processed_thread field.
2721 class RememberProcessedThread: public StackObj {
2722 NamedThread* _cur_thr;
2723 public:
2724 RememberProcessedThread(JavaThread* jthr) {
2725 Thread* thread = Thread::current();
2726 if (thread->is_Named_thread()) {
2727 _cur_thr = (NamedThread *)thread;
2728 _cur_thr->set_processed_thread(jthr);
2729 } else {
2730 _cur_thr = NULL;
2731 }
2732 }
2733
2734 ~RememberProcessedThread() {
2735 if (_cur_thr) {
2736 _cur_thr->set_processed_thread(NULL);
2737 }
2738 }
2739 };
2740
2741 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2742 // Verify that the deferred card marks have been flushed.
2743 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2744
2745 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2746 // since there may be more than one thread using each ThreadProfiler.
2747
2748 // Traverse the GCHandles
2749 Thread::oops_do(f, cld_f, cf);
2750
2751 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2752
2753 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2754 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2755
2756 if (has_last_Java_frame()) {
2757 // Record JavaThread to GC thread
2758 RememberProcessedThread rpt(this);
2759
2760 // Traverse the privileged stack
2761 if (_privileged_stack_top != NULL) {
2762 _privileged_stack_top->oops_do(f);
2763 }
2764
2765 // traverse the registered growable array
2766 if (_array_for_gc != NULL) {
2767 for (int index = 0; index < _array_for_gc->length(); index++) {
2768 f->do_oop(_array_for_gc->adr_at(index));
2769 }
2770 }
2771
2772 // Traverse the monitor chunks
2773 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2774 chunk->oops_do(f);
2775 }
2776
2777 // Traverse the execution stack
2778 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2779 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2780 }
2781 }
2782
2783 // callee_target is never live across a gc point so NULL it here should
2784 // it still contain a methdOop.
2785
2786 set_callee_target(NULL);
2787
2788 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2789 // If we have deferred set_locals there might be oops waiting to be
2790 // written
2791 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2792 if (list != NULL) {
2793 for (int i = 0; i < list->length(); i++) {
2794 list->at(i)->oops_do(f);
2795 }
2796 }
2797
2798 // Traverse instance variables at the end since the GC may be moving things
2799 // around using this function
2800 f->do_oop((oop*) &_threadObj);
2801 f->do_oop((oop*) &_vm_result);
2802 f->do_oop((oop*) &_exception_oop);
2803 f->do_oop((oop*) &_pending_async_exception);
2804
2805 if (jvmti_thread_state() != NULL) {
2806 jvmti_thread_state()->oops_do(f);
2807 }
2808 }
2809
2810 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2811 Thread::nmethods_do(cf); // (super method is a no-op)
2812
2813 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2814 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2815
2816 if (has_last_Java_frame()) {
2817 // Traverse the execution stack
2818 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2819 fst.current()->nmethods_do(cf);
2820 }
2821 }
2822 }
2823
2824 void JavaThread::metadata_do(void f(Metadata*)) {
2825 if (has_last_Java_frame()) {
2826 // Traverse the execution stack to call f() on the methods in the stack
2827 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2828 fst.current()->metadata_do(f);
2829 }
2830 } else if (is_Compiler_thread()) {
2831 // need to walk ciMetadata in current compile tasks to keep alive.
2832 CompilerThread* ct = (CompilerThread*)this;
2833 if (ct->env() != NULL) {
2834 ct->env()->metadata_do(f);
2835 }
2836 if (ct->task() != NULL) {
2837 ct->task()->metadata_do(f);
2838 }
2839 }
2840 }
2841
2842 // Printing
2843 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2844 switch (_thread_state) {
2845 case _thread_uninitialized: return "_thread_uninitialized";
2846 case _thread_new: return "_thread_new";
2847 case _thread_new_trans: return "_thread_new_trans";
2848 case _thread_in_native: return "_thread_in_native";
2849 case _thread_in_native_trans: return "_thread_in_native_trans";
2850 case _thread_in_vm: return "_thread_in_vm";
2851 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2852 case _thread_in_Java: return "_thread_in_Java";
2853 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2854 case _thread_blocked: return "_thread_blocked";
2855 case _thread_blocked_trans: return "_thread_blocked_trans";
2856 default: return "unknown thread state";
2857 }
2858 }
2859
2860 #ifndef PRODUCT
2861 void JavaThread::print_thread_state_on(outputStream *st) const {
2862 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2863 };
2864 void JavaThread::print_thread_state() const {
2865 print_thread_state_on(tty);
2866 }
2867 #endif // PRODUCT
2868
2869 // Called by Threads::print() for VM_PrintThreads operation
2870 void JavaThread::print_on(outputStream *st) const {
2871 st->print("\"%s\" ", get_thread_name());
2872 oop thread_oop = threadObj();
2873 if (thread_oop != NULL) {
2874 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2875 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2876 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2877 }
2878 Thread::print_on(st);
2879 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2880 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2881 if (thread_oop != NULL) {
2882 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2883 }
2884 #ifndef PRODUCT
2885 print_thread_state_on(st);
2886 _safepoint_state->print_on(st);
2887 #endif // PRODUCT
2888 if (is_Compiler_thread()) {
2889 CompilerThread* ct = (CompilerThread*)this;
2890 if (ct->task() != NULL) {
2891 st->print(" Compiling: ");
2892 ct->task()->print(st, NULL, true, false);
2893 } else {
2894 st->print(" No compile task");
2895 }
2896 st->cr();
2897 }
2898 }
2899
2900 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
2901 st->print("%s", get_thread_name_string(buf, buflen));
2902 }
2903
2904 // Called by fatal error handler. The difference between this and
2905 // JavaThread::print() is that we can't grab lock or allocate memory.
2906 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2907 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2908 oop thread_obj = threadObj();
2909 if (thread_obj != NULL) {
2910 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2911 }
2912 st->print(" [");
2913 st->print("%s", _get_thread_state_name(_thread_state));
2914 if (osthread()) {
2915 st->print(", id=%d", osthread()->thread_id());
2916 }
2917 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2918 p2i(stack_end()), p2i(stack_base()));
2919 st->print("]");
2920 return;
2921 }
2922
2923 // Verification
2924
2925 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2926
2927 void JavaThread::verify() {
2928 // Verify oops in the thread.
2929 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2930
2931 // Verify the stack frames.
2932 frames_do(frame_verify);
2933 }
2934
2935 // CR 6300358 (sub-CR 2137150)
2936 // Most callers of this method assume that it can't return NULL but a
2937 // thread may not have a name whilst it is in the process of attaching to
2938 // the VM - see CR 6412693, and there are places where a JavaThread can be
2939 // seen prior to having it's threadObj set (eg JNI attaching threads and
2940 // if vm exit occurs during initialization). These cases can all be accounted
2941 // for such that this method never returns NULL.
2942 const char* JavaThread::get_thread_name() const {
2943 #ifdef ASSERT
2944 // early safepoints can hit while current thread does not yet have TLS
2945 if (!SafepointSynchronize::is_at_safepoint()) {
2946 Thread *cur = Thread::current();
2947 if (!(cur->is_Java_thread() && cur == this)) {
2948 // Current JavaThreads are allowed to get their own name without
2949 // the Threads_lock.
2950 assert_locked_or_safepoint(Threads_lock);
2951 }
2952 }
2953 #endif // ASSERT
2954 return get_thread_name_string();
2955 }
2956
2957 // Returns a non-NULL representation of this thread's name, or a suitable
2958 // descriptive string if there is no set name
2959 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2960 const char* name_str;
2961 oop thread_obj = threadObj();
2962 if (thread_obj != NULL) {
2963 oop name = java_lang_Thread::name(thread_obj);
2964 if (name != NULL) {
2965 if (buf == NULL) {
2966 name_str = java_lang_String::as_utf8_string(name);
2967 } else {
2968 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2969 }
2970 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2971 name_str = "<no-name - thread is attaching>";
2972 } else {
2973 name_str = Thread::name();
2974 }
2975 } else {
2976 name_str = Thread::name();
2977 }
2978 assert(name_str != NULL, "unexpected NULL thread name");
2979 return name_str;
2980 }
2981
2982
2983 const char* JavaThread::get_threadgroup_name() const {
2984 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2985 oop thread_obj = threadObj();
2986 if (thread_obj != NULL) {
2987 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2988 if (thread_group != NULL) {
2989 // ThreadGroup.name can be null
2990 return java_lang_ThreadGroup::name(thread_group);
2991 }
2992 }
2993 return NULL;
2994 }
2995
2996 const char* JavaThread::get_parent_name() const {
2997 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2998 oop thread_obj = threadObj();
2999 if (thread_obj != NULL) {
3000 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3001 if (thread_group != NULL) {
3002 oop parent = java_lang_ThreadGroup::parent(thread_group);
3003 if (parent != NULL) {
3004 // ThreadGroup.name can be null
3005 return java_lang_ThreadGroup::name(parent);
3006 }
3007 }
3008 }
3009 return NULL;
3010 }
3011
3012 ThreadPriority JavaThread::java_priority() const {
3013 oop thr_oop = threadObj();
3014 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3015 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3016 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3017 return priority;
3018 }
3019
3020 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3021
3022 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3023 // Link Java Thread object <-> C++ Thread
3024
3025 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3026 // and put it into a new Handle. The Handle "thread_oop" can then
3027 // be used to pass the C++ thread object to other methods.
3028
3029 // Set the Java level thread object (jthread) field of the
3030 // new thread (a JavaThread *) to C++ thread object using the
3031 // "thread_oop" handle.
3032
3033 // Set the thread field (a JavaThread *) of the
3034 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3035
3036 Handle thread_oop(Thread::current(),
3037 JNIHandles::resolve_non_null(jni_thread));
3038 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3039 "must be initialized");
3040 set_threadObj(thread_oop());
3041 java_lang_Thread::set_thread(thread_oop(), this);
3042
3043 if (prio == NoPriority) {
3044 prio = java_lang_Thread::priority(thread_oop());
3045 assert(prio != NoPriority, "A valid priority should be present");
3046 }
3047
3048 // Push the Java priority down to the native thread; needs Threads_lock
3049 Thread::set_priority(this, prio);
3050
3051 prepare_ext();
3052
3053 // Add the new thread to the Threads list and set it in motion.
3054 // We must have threads lock in order to call Threads::add.
3055 // It is crucial that we do not block before the thread is
3056 // added to the Threads list for if a GC happens, then the java_thread oop
3057 // will not be visited by GC.
3058 Threads::add(this);
3059 }
3060
3061 oop JavaThread::current_park_blocker() {
3062 // Support for JSR-166 locks
3063 oop thread_oop = threadObj();
3064 if (thread_oop != NULL &&
3065 JDK_Version::current().supports_thread_park_blocker()) {
3066 return java_lang_Thread::park_blocker(thread_oop);
3067 }
3068 return NULL;
3069 }
3070
3071
3072 void JavaThread::print_stack_on(outputStream* st) {
3073 if (!has_last_Java_frame()) return;
3074 ResourceMark rm;
3075 HandleMark hm;
3076
3077 RegisterMap reg_map(this);
3078 vframe* start_vf = last_java_vframe(®_map);
3079 int count = 0;
3080 for (vframe* f = start_vf; f; f = f->sender()) {
3081 if (f->is_java_frame()) {
3082 javaVFrame* jvf = javaVFrame::cast(f);
3083 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3084
3085 // Print out lock information
3086 if (JavaMonitorsInStackTrace) {
3087 jvf->print_lock_info_on(st, count);
3088 }
3089 } else {
3090 // Ignore non-Java frames
3091 }
3092
3093 // Bail-out case for too deep stacks
3094 count++;
3095 if (MaxJavaStackTraceDepth == count) return;
3096 }
3097 }
3098
3099
3100 // JVMTI PopFrame support
3101 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3102 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3103 if (in_bytes(size_in_bytes) != 0) {
3104 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3105 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3106 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3107 }
3108 }
3109
3110 void* JavaThread::popframe_preserved_args() {
3111 return _popframe_preserved_args;
3112 }
3113
3114 ByteSize JavaThread::popframe_preserved_args_size() {
3115 return in_ByteSize(_popframe_preserved_args_size);
3116 }
3117
3118 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3119 int sz = in_bytes(popframe_preserved_args_size());
3120 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3121 return in_WordSize(sz / wordSize);
3122 }
3123
3124 void JavaThread::popframe_free_preserved_args() {
3125 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3126 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3127 _popframe_preserved_args = NULL;
3128 _popframe_preserved_args_size = 0;
3129 }
3130
3131 #ifndef PRODUCT
3132
3133 void JavaThread::trace_frames() {
3134 tty->print_cr("[Describe stack]");
3135 int frame_no = 1;
3136 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3137 tty->print(" %d. ", frame_no++);
3138 fst.current()->print_value_on(tty, this);
3139 tty->cr();
3140 }
3141 }
3142
3143 class PrintAndVerifyOopClosure: public OopClosure {
3144 protected:
3145 template <class T> inline void do_oop_work(T* p) {
3146 oop obj = oopDesc::load_decode_heap_oop(p);
3147 if (obj == NULL) return;
3148 tty->print(INTPTR_FORMAT ": ", p2i(p));
3149 if (obj->is_oop_or_null()) {
3150 if (obj->is_objArray()) {
3151 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3152 } else {
3153 obj->print();
3154 }
3155 } else {
3156 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3157 }
3158 tty->cr();
3159 }
3160 public:
3161 virtual void do_oop(oop* p) { do_oop_work(p); }
3162 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3163 };
3164
3165
3166 static void oops_print(frame* f, const RegisterMap *map) {
3167 PrintAndVerifyOopClosure print;
3168 f->print_value();
3169 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3170 }
3171
3172 // Print our all the locations that contain oops and whether they are
3173 // valid or not. This useful when trying to find the oldest frame
3174 // where an oop has gone bad since the frame walk is from youngest to
3175 // oldest.
3176 void JavaThread::trace_oops() {
3177 tty->print_cr("[Trace oops]");
3178 frames_do(oops_print);
3179 }
3180
3181
3182 #ifdef ASSERT
3183 // Print or validate the layout of stack frames
3184 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3185 ResourceMark rm;
3186 PRESERVE_EXCEPTION_MARK;
3187 FrameValues values;
3188 int frame_no = 0;
3189 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3190 fst.current()->describe(values, ++frame_no);
3191 if (depth == frame_no) break;
3192 }
3193 if (validate_only) {
3194 values.validate();
3195 } else {
3196 tty->print_cr("[Describe stack layout]");
3197 values.print(this);
3198 }
3199 }
3200 #endif
3201
3202 void JavaThread::trace_stack_from(vframe* start_vf) {
3203 ResourceMark rm;
3204 int vframe_no = 1;
3205 for (vframe* f = start_vf; f; f = f->sender()) {
3206 if (f->is_java_frame()) {
3207 javaVFrame::cast(f)->print_activation(vframe_no++);
3208 } else {
3209 f->print();
3210 }
3211 if (vframe_no > StackPrintLimit) {
3212 tty->print_cr("...<more frames>...");
3213 return;
3214 }
3215 }
3216 }
3217
3218
3219 void JavaThread::trace_stack() {
3220 if (!has_last_Java_frame()) return;
3221 ResourceMark rm;
3222 HandleMark hm;
3223 RegisterMap reg_map(this);
3224 trace_stack_from(last_java_vframe(®_map));
3225 }
3226
3227
3228 #endif // PRODUCT
3229
3230
3231 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3232 assert(reg_map != NULL, "a map must be given");
3233 frame f = last_frame();
3234 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3235 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3236 }
3237 return NULL;
3238 }
3239
3240
3241 Klass* JavaThread::security_get_caller_class(int depth) {
3242 vframeStream vfst(this);
3243 vfst.security_get_caller_frame(depth);
3244 if (!vfst.at_end()) {
3245 return vfst.method()->method_holder();
3246 }
3247 return NULL;
3248 }
3249
3250 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3251 assert(thread->is_Compiler_thread(), "must be compiler thread");
3252 CompileBroker::compiler_thread_loop();
3253 }
3254
3255 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3256 NMethodSweeper::sweeper_loop();
3257 }
3258
3259 // Create a CompilerThread
3260 CompilerThread::CompilerThread(CompileQueue* queue,
3261 CompilerCounters* counters)
3262 : JavaThread(&compiler_thread_entry) {
3263 _env = NULL;
3264 _log = NULL;
3265 _task = NULL;
3266 _queue = queue;
3267 _counters = counters;
3268 _buffer_blob = NULL;
3269 _compiler = NULL;
3270
3271 #ifndef PRODUCT
3272 _ideal_graph_printer = NULL;
3273 #endif
3274 }
3275
3276 bool CompilerThread::can_call_java() const {
3277 return _compiler != NULL && _compiler->is_jvmci();
3278 }
3279
3280 // Create sweeper thread
3281 CodeCacheSweeperThread::CodeCacheSweeperThread()
3282 : JavaThread(&sweeper_thread_entry) {
3283 _scanned_nmethod = NULL;
3284 }
3285 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3286 JavaThread::oops_do(f, cld_f, cf);
3287 if (_scanned_nmethod != NULL && cf != NULL) {
3288 // Safepoints can occur when the sweeper is scanning an nmethod so
3289 // process it here to make sure it isn't unloaded in the middle of
3290 // a scan.
3291 cf->do_code_blob(_scanned_nmethod);
3292 }
3293 }
3294
3295
3296 // ======= Threads ========
3297
3298 // The Threads class links together all active threads, and provides
3299 // operations over all threads. It is protected by its own Mutex
3300 // lock, which is also used in other contexts to protect thread
3301 // operations from having the thread being operated on from exiting
3302 // and going away unexpectedly (e.g., safepoint synchronization)
3303
3304 JavaThread* Threads::_thread_list = NULL;
3305 int Threads::_number_of_threads = 0;
3306 int Threads::_number_of_non_daemon_threads = 0;
3307 int Threads::_return_code = 0;
3308 int Threads::_thread_claim_parity = 0;
3309 size_t JavaThread::_stack_size_at_create = 0;
3310 #ifdef ASSERT
3311 bool Threads::_vm_complete = false;
3312 #endif
3313
3314 // All JavaThreads
3315 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3316
3317 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3318 void Threads::threads_do(ThreadClosure* tc) {
3319 assert_locked_or_safepoint(Threads_lock);
3320 // ALL_JAVA_THREADS iterates through all JavaThreads
3321 ALL_JAVA_THREADS(p) {
3322 tc->do_thread(p);
3323 }
3324 // Someday we could have a table or list of all non-JavaThreads.
3325 // For now, just manually iterate through them.
3326 tc->do_thread(VMThread::vm_thread());
3327 Universe::heap()->gc_threads_do(tc);
3328 WatcherThread *wt = WatcherThread::watcher_thread();
3329 // Strictly speaking, the following NULL check isn't sufficient to make sure
3330 // the data for WatcherThread is still valid upon being examined. However,
3331 // considering that WatchThread terminates when the VM is on the way to
3332 // exit at safepoint, the chance of the above is extremely small. The right
3333 // way to prevent termination of WatcherThread would be to acquire
3334 // Terminator_lock, but we can't do that without violating the lock rank
3335 // checking in some cases.
3336 if (wt != NULL) {
3337 tc->do_thread(wt);
3338 }
3339
3340 // If CompilerThreads ever become non-JavaThreads, add them here
3341 }
3342
3343 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3344 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3345
3346 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3347 create_vm_init_libraries();
3348 }
3349
3350 initialize_class(vmSymbols::java_lang_String(), CHECK);
3351
3352 // Inject CompactStrings value after the static initializers for String ran.
3353 java_lang_String::set_compact_strings(CompactStrings);
3354
3355 // Initialize java_lang.System (needed before creating the thread)
3356 initialize_class(vmSymbols::java_lang_System(), CHECK);
3357 // The VM creates & returns objects of this class. Make sure it's initialized.
3358 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3359 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3360 Handle thread_group = create_initial_thread_group(CHECK);
3361 Universe::set_main_thread_group(thread_group());
3362 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3363 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3364 main_thread->set_threadObj(thread_object);
3365 // Set thread status to running since main thread has
3366 // been started and running.
3367 java_lang_Thread::set_thread_status(thread_object,
3368 java_lang_Thread::RUNNABLE);
3369
3370 // The VM preresolves methods to these classes. Make sure that they get initialized
3371 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3372 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3373 call_initializeSystemClass(CHECK);
3374
3375 // get the Java runtime name after java.lang.System is initialized
3376 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3377 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3378
3379 // an instance of OutOfMemory exception has been allocated earlier
3380 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3381 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3382 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3383 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3384 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3385 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3386 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3387 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3388 }
3389
3390 void Threads::initialize_jsr292_core_classes(TRAPS) {
3391 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3392 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3393 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3394 }
3395
3396 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3397 extern void JDK_Version_init();
3398
3399 // Preinitialize version info.
3400 VM_Version::early_initialize();
3401
3402 // Check version
3403 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3404
3405 // Initialize library-based TLS
3406 ThreadLocalStorage::init();
3407
3408 // Initialize the output stream module
3409 ostream_init();
3410
3411 // Process java launcher properties.
3412 Arguments::process_sun_java_launcher_properties(args);
3413
3414 // Initialize the os module
3415 os::init();
3416
3417 // Record VM creation timing statistics
3418 TraceVmCreationTime create_vm_timer;
3419 create_vm_timer.start();
3420
3421 // Initialize system properties.
3422 Arguments::init_system_properties();
3423
3424 // So that JDK version can be used as a discriminator when parsing arguments
3425 JDK_Version_init();
3426
3427 // Update/Initialize System properties after JDK version number is known
3428 Arguments::init_version_specific_system_properties();
3429
3430 // Make sure to initialize log configuration *before* parsing arguments
3431 LogConfiguration::initialize(create_vm_timer.begin_time());
3432
3433 // Parse arguments
3434 jint parse_result = Arguments::parse(args);
3435 if (parse_result != JNI_OK) return parse_result;
3436
3437 os::init_before_ergo();
3438
3439 jint ergo_result = Arguments::apply_ergo();
3440 if (ergo_result != JNI_OK) return ergo_result;
3441
3442 // Final check of all ranges after ergonomics which may change values.
3443 if (!CommandLineFlagRangeList::check_ranges()) {
3444 return JNI_EINVAL;
3445 }
3446
3447 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3448 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3449 if (!constraint_result) {
3450 return JNI_EINVAL;
3451 }
3452
3453 if (PauseAtStartup) {
3454 os::pause();
3455 }
3456
3457 HOTSPOT_VM_INIT_BEGIN();
3458
3459 // Timing (must come after argument parsing)
3460 TraceTime timer("Create VM", TraceStartupTime);
3461
3462 // Initialize the os module after parsing the args
3463 jint os_init_2_result = os::init_2();
3464 if (os_init_2_result != JNI_OK) return os_init_2_result;
3465
3466 jint adjust_after_os_result = Arguments::adjust_after_os();
3467 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3468
3469 // Initialize output stream logging
3470 ostream_init_log();
3471
3472 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3473 // Must be before create_vm_init_agents()
3474 if (Arguments::init_libraries_at_startup()) {
3475 convert_vm_init_libraries_to_agents();
3476 }
3477
3478 // Launch -agentlib/-agentpath and converted -Xrun agents
3479 if (Arguments::init_agents_at_startup()) {
3480 create_vm_init_agents();
3481 }
3482
3483 // Initialize Threads state
3484 _thread_list = NULL;
3485 _number_of_threads = 0;
3486 _number_of_non_daemon_threads = 0;
3487
3488 // Initialize global data structures and create system classes in heap
3489 vm_init_globals();
3490
3491 #if INCLUDE_JVMCI
3492 if (JVMCICounterSize > 0) {
3493 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3494 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3495 } else {
3496 JavaThread::_jvmci_old_thread_counters = NULL;
3497 }
3498 #endif // INCLUDE_JVMCI
3499
3500 // Attach the main thread to this os thread
3501 JavaThread* main_thread = new JavaThread();
3502 main_thread->set_thread_state(_thread_in_vm);
3503 main_thread->initialize_thread_current();
3504 // must do this before set_active_handles
3505 main_thread->record_stack_base_and_size();
3506 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3507
3508 if (!main_thread->set_as_starting_thread()) {
3509 vm_shutdown_during_initialization(
3510 "Failed necessary internal allocation. Out of swap space");
3511 delete main_thread;
3512 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3513 return JNI_ENOMEM;
3514 }
3515
3516 // Enable guard page *after* os::create_main_thread(), otherwise it would
3517 // crash Linux VM, see notes in os_linux.cpp.
3518 main_thread->create_stack_guard_pages();
3519
3520 // Initialize Java-Level synchronization subsystem
3521 ObjectMonitor::Initialize();
3522
3523 // Initialize global modules
3524 jint status = init_globals();
3525 if (status != JNI_OK) {
3526 delete main_thread;
3527 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3528 return status;
3529 }
3530
3531 // Should be done after the heap is fully created
3532 main_thread->cache_global_variables();
3533
3534 HandleMark hm;
3535
3536 { MutexLocker mu(Threads_lock);
3537 Threads::add(main_thread);
3538 }
3539
3540 // Any JVMTI raw monitors entered in onload will transition into
3541 // real raw monitor. VM is setup enough here for raw monitor enter.
3542 JvmtiExport::transition_pending_onload_raw_monitors();
3543
3544 // Create the VMThread
3545 { TraceTime timer("Start VMThread", TraceStartupTime);
3546 VMThread::create();
3547 Thread* vmthread = VMThread::vm_thread();
3548
3549 if (!os::create_thread(vmthread, os::vm_thread)) {
3550 vm_exit_during_initialization("Cannot create VM thread. "
3551 "Out of system resources.");
3552 }
3553
3554 // Wait for the VM thread to become ready, and VMThread::run to initialize
3555 // Monitors can have spurious returns, must always check another state flag
3556 {
3557 MutexLocker ml(Notify_lock);
3558 os::start_thread(vmthread);
3559 while (vmthread->active_handles() == NULL) {
3560 Notify_lock->wait();
3561 }
3562 }
3563 }
3564
3565 assert(Universe::is_fully_initialized(), "not initialized");
3566 if (VerifyDuringStartup) {
3567 // Make sure we're starting with a clean slate.
3568 VM_Verify verify_op;
3569 VMThread::execute(&verify_op);
3570 }
3571
3572 Thread* THREAD = Thread::current();
3573
3574 // At this point, the Universe is initialized, but we have not executed
3575 // any byte code. Now is a good time (the only time) to dump out the
3576 // internal state of the JVM for sharing.
3577 if (DumpSharedSpaces) {
3578 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3579 ShouldNotReachHere();
3580 }
3581
3582 // Always call even when there are not JVMTI environments yet, since environments
3583 // may be attached late and JVMTI must track phases of VM execution
3584 JvmtiExport::enter_start_phase();
3585
3586 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3587 JvmtiExport::post_vm_start();
3588
3589 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3590
3591 // We need this for ClassDataSharing - the initial vm.info property is set
3592 // with the default value of CDS "sharing" which may be reset through
3593 // command line options.
3594 reset_vm_info_property(CHECK_JNI_ERR);
3595
3596 quicken_jni_functions();
3597
3598 // Must be run after init_ft which initializes ft_enabled
3599 if (TRACE_INITIALIZE() != JNI_OK) {
3600 vm_exit_during_initialization("Failed to initialize tracing backend");
3601 }
3602
3603 // Set flag that basic initialization has completed. Used by exceptions and various
3604 // debug stuff, that does not work until all basic classes have been initialized.
3605 set_init_completed();
3606
3607 LogConfiguration::post_initialize();
3608 Metaspace::post_initialize();
3609
3610 HOTSPOT_VM_INIT_END();
3611
3612 // record VM initialization completion time
3613 #if INCLUDE_MANAGEMENT
3614 Management::record_vm_init_completed();
3615 #endif // INCLUDE_MANAGEMENT
3616
3617 // Compute system loader. Note that this has to occur after set_init_completed, since
3618 // valid exceptions may be thrown in the process.
3619 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3620 // set_init_completed has just been called, causing exceptions not to be shortcut
3621 // anymore. We call vm_exit_during_initialization directly instead.
3622 SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR));
3623
3624 #if INCLUDE_ALL_GCS
3625 // Support for ConcurrentMarkSweep. This should be cleaned up
3626 // and better encapsulated. The ugly nested if test would go away
3627 // once things are properly refactored. XXX YSR
3628 if (UseConcMarkSweepGC || UseG1GC) {
3629 if (UseConcMarkSweepGC) {
3630 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3631 } else {
3632 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3633 }
3634 }
3635 #endif // INCLUDE_ALL_GCS
3636
3637 // Always call even when there are not JVMTI environments yet, since environments
3638 // may be attached late and JVMTI must track phases of VM execution
3639 JvmtiExport::enter_live_phase();
3640
3641 // Signal Dispatcher needs to be started before VMInit event is posted
3642 os::signal_init();
3643
3644 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3645 if (!DisableAttachMechanism) {
3646 AttachListener::vm_start();
3647 if (StartAttachListener || AttachListener::init_at_startup()) {
3648 AttachListener::init();
3649 }
3650 }
3651
3652 // Launch -Xrun agents
3653 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3654 // back-end can launch with -Xdebug -Xrunjdwp.
3655 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3656 create_vm_init_libraries();
3657 }
3658
3659 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3660 JvmtiExport::post_vm_initialized();
3661
3662 if (TRACE_START() != JNI_OK) {
3663 vm_exit_during_initialization("Failed to start tracing backend.");
3664 }
3665
3666 if (CleanChunkPoolAsync) {
3667 Chunk::start_chunk_pool_cleaner_task();
3668 }
3669
3670 #if INCLUDE_JVMCI
3671 if (EnableJVMCI) {
3672 const char* jvmciCompiler = Arguments::PropertyList_get_value(Arguments::system_properties(), "jvmci.compiler");
3673 if (jvmciCompiler != NULL) {
3674 JVMCIRuntime::save_compiler(jvmciCompiler);
3675 }
3676 }
3677 #endif // INCLUDE_JVMCI
3678
3679 // initialize compiler(s)
3680 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI
3681 CompileBroker::compilation_init(CHECK_JNI_ERR);
3682 #endif
3683
3684 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3685 // It is done after compilers are initialized, because otherwise compilations of
3686 // signature polymorphic MH intrinsics can be missed
3687 // (see SystemDictionary::find_method_handle_intrinsic).
3688 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3689
3690 #if INCLUDE_MANAGEMENT
3691 Management::initialize(THREAD);
3692
3693 if (HAS_PENDING_EXCEPTION) {
3694 // management agent fails to start possibly due to
3695 // configuration problem and is responsible for printing
3696 // stack trace if appropriate. Simply exit VM.
3697 vm_exit(1);
3698 }
3699 #endif // INCLUDE_MANAGEMENT
3700
3701 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3702 if (MemProfiling) MemProfiler::engage();
3703 StatSampler::engage();
3704 if (CheckJNICalls) JniPeriodicChecker::engage();
3705
3706 BiasedLocking::init();
3707
3708 #if INCLUDE_RTM_OPT
3709 RTMLockingCounters::init();
3710 #endif
3711
3712 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3713 call_postVMInitHook(THREAD);
3714 // The Java side of PostVMInitHook.run must deal with all
3715 // exceptions and provide means of diagnosis.
3716 if (HAS_PENDING_EXCEPTION) {
3717 CLEAR_PENDING_EXCEPTION;
3718 }
3719 }
3720
3721 {
3722 MutexLocker ml(PeriodicTask_lock);
3723 // Make sure the WatcherThread can be started by WatcherThread::start()
3724 // or by dynamic enrollment.
3725 WatcherThread::make_startable();
3726 // Start up the WatcherThread if there are any periodic tasks
3727 // NOTE: All PeriodicTasks should be registered by now. If they
3728 // aren't, late joiners might appear to start slowly (we might
3729 // take a while to process their first tick).
3730 if (PeriodicTask::num_tasks() > 0) {
3731 WatcherThread::start();
3732 }
3733 }
3734
3735 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3736
3737 create_vm_timer.end();
3738 #ifdef ASSERT
3739 _vm_complete = true;
3740 #endif
3741 return JNI_OK;
3742 }
3743
3744 // type for the Agent_OnLoad and JVM_OnLoad entry points
3745 extern "C" {
3746 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3747 }
3748 // Find a command line agent library and return its entry point for
3749 // -agentlib: -agentpath: -Xrun
3750 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3751 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3752 const char *on_load_symbols[],
3753 size_t num_symbol_entries) {
3754 OnLoadEntry_t on_load_entry = NULL;
3755 void *library = NULL;
3756
3757 if (!agent->valid()) {
3758 char buffer[JVM_MAXPATHLEN];
3759 char ebuf[1024] = "";
3760 const char *name = agent->name();
3761 const char *msg = "Could not find agent library ";
3762
3763 // First check to see if agent is statically linked into executable
3764 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3765 library = agent->os_lib();
3766 } else if (agent->is_absolute_path()) {
3767 library = os::dll_load(name, ebuf, sizeof ebuf);
3768 if (library == NULL) {
3769 const char *sub_msg = " in absolute path, with error: ";
3770 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3771 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3772 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3773 // If we can't find the agent, exit.
3774 vm_exit_during_initialization(buf, NULL);
3775 FREE_C_HEAP_ARRAY(char, buf);
3776 }
3777 } else {
3778 // Try to load the agent from the standard dll directory
3779 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3780 name)) {
3781 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3782 }
3783 if (library == NULL) { // Try the local directory
3784 char ns[1] = {0};
3785 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3786 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3787 }
3788 if (library == NULL) {
3789 const char *sub_msg = " on the library path, with error: ";
3790 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3791 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3792 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3793 // If we can't find the agent, exit.
3794 vm_exit_during_initialization(buf, NULL);
3795 FREE_C_HEAP_ARRAY(char, buf);
3796 }
3797 }
3798 }
3799 agent->set_os_lib(library);
3800 agent->set_valid();
3801 }
3802
3803 // Find the OnLoad function.
3804 on_load_entry =
3805 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3806 false,
3807 on_load_symbols,
3808 num_symbol_entries));
3809 return on_load_entry;
3810 }
3811
3812 // Find the JVM_OnLoad entry point
3813 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3814 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3815 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3816 }
3817
3818 // Find the Agent_OnLoad entry point
3819 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3820 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3821 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3822 }
3823
3824 // For backwards compatibility with -Xrun
3825 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3826 // treated like -agentpath:
3827 // Must be called before agent libraries are created
3828 void Threads::convert_vm_init_libraries_to_agents() {
3829 AgentLibrary* agent;
3830 AgentLibrary* next;
3831
3832 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3833 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3834 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3835
3836 // If there is an JVM_OnLoad function it will get called later,
3837 // otherwise see if there is an Agent_OnLoad
3838 if (on_load_entry == NULL) {
3839 on_load_entry = lookup_agent_on_load(agent);
3840 if (on_load_entry != NULL) {
3841 // switch it to the agent list -- so that Agent_OnLoad will be called,
3842 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3843 Arguments::convert_library_to_agent(agent);
3844 } else {
3845 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3846 }
3847 }
3848 }
3849 }
3850
3851 // Create agents for -agentlib: -agentpath: and converted -Xrun
3852 // Invokes Agent_OnLoad
3853 // Called very early -- before JavaThreads exist
3854 void Threads::create_vm_init_agents() {
3855 extern struct JavaVM_ main_vm;
3856 AgentLibrary* agent;
3857
3858 JvmtiExport::enter_onload_phase();
3859
3860 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3861 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3862
3863 if (on_load_entry != NULL) {
3864 // Invoke the Agent_OnLoad function
3865 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3866 if (err != JNI_OK) {
3867 vm_exit_during_initialization("agent library failed to init", agent->name());
3868 }
3869 } else {
3870 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3871 }
3872 }
3873 JvmtiExport::enter_primordial_phase();
3874 }
3875
3876 extern "C" {
3877 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3878 }
3879
3880 void Threads::shutdown_vm_agents() {
3881 // Send any Agent_OnUnload notifications
3882 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3883 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3884 extern struct JavaVM_ main_vm;
3885 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3886
3887 // Find the Agent_OnUnload function.
3888 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3889 os::find_agent_function(agent,
3890 false,
3891 on_unload_symbols,
3892 num_symbol_entries));
3893
3894 // Invoke the Agent_OnUnload function
3895 if (unload_entry != NULL) {
3896 JavaThread* thread = JavaThread::current();
3897 ThreadToNativeFromVM ttn(thread);
3898 HandleMark hm(thread);
3899 (*unload_entry)(&main_vm);
3900 }
3901 }
3902 }
3903
3904 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3905 // Invokes JVM_OnLoad
3906 void Threads::create_vm_init_libraries() {
3907 extern struct JavaVM_ main_vm;
3908 AgentLibrary* agent;
3909
3910 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3911 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3912
3913 if (on_load_entry != NULL) {
3914 // Invoke the JVM_OnLoad function
3915 JavaThread* thread = JavaThread::current();
3916 ThreadToNativeFromVM ttn(thread);
3917 HandleMark hm(thread);
3918 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3919 if (err != JNI_OK) {
3920 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3921 }
3922 } else {
3923 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3924 }
3925 }
3926 }
3927
3928 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3929 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3930
3931 JavaThread* java_thread = NULL;
3932 // Sequential search for now. Need to do better optimization later.
3933 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3934 oop tobj = thread->threadObj();
3935 if (!thread->is_exiting() &&
3936 tobj != NULL &&
3937 java_tid == java_lang_Thread::thread_id(tobj)) {
3938 java_thread = thread;
3939 break;
3940 }
3941 }
3942 return java_thread;
3943 }
3944
3945
3946 // Last thread running calls java.lang.Shutdown.shutdown()
3947 void JavaThread::invoke_shutdown_hooks() {
3948 HandleMark hm(this);
3949
3950 // We could get here with a pending exception, if so clear it now.
3951 if (this->has_pending_exception()) {
3952 this->clear_pending_exception();
3953 }
3954
3955 EXCEPTION_MARK;
3956 Klass* k =
3957 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3958 THREAD);
3959 if (k != NULL) {
3960 // SystemDictionary::resolve_or_null will return null if there was
3961 // an exception. If we cannot load the Shutdown class, just don't
3962 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3963 // and finalizers (if runFinalizersOnExit is set) won't be run.
3964 // Note that if a shutdown hook was registered or runFinalizersOnExit
3965 // was called, the Shutdown class would have already been loaded
3966 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3967 instanceKlassHandle shutdown_klass (THREAD, k);
3968 JavaValue result(T_VOID);
3969 JavaCalls::call_static(&result,
3970 shutdown_klass,
3971 vmSymbols::shutdown_method_name(),
3972 vmSymbols::void_method_signature(),
3973 THREAD);
3974 }
3975 CLEAR_PENDING_EXCEPTION;
3976 }
3977
3978 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3979 // the program falls off the end of main(). Another VM exit path is through
3980 // vm_exit() when the program calls System.exit() to return a value or when
3981 // there is a serious error in VM. The two shutdown paths are not exactly
3982 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3983 // and VM_Exit op at VM level.
3984 //
3985 // Shutdown sequence:
3986 // + Shutdown native memory tracking if it is on
3987 // + Wait until we are the last non-daemon thread to execute
3988 // <-- every thing is still working at this moment -->
3989 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3990 // shutdown hooks, run finalizers if finalization-on-exit
3991 // + Call before_exit(), prepare for VM exit
3992 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3993 // currently the only user of this mechanism is File.deleteOnExit())
3994 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3995 // post thread end and vm death events to JVMTI,
3996 // stop signal thread
3997 // + Call JavaThread::exit(), it will:
3998 // > release JNI handle blocks, remove stack guard pages
3999 // > remove this thread from Threads list
4000 // <-- no more Java code from this thread after this point -->
4001 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4002 // the compiler threads at safepoint
4003 // <-- do not use anything that could get blocked by Safepoint -->
4004 // + Disable tracing at JNI/JVM barriers
4005 // + Set _vm_exited flag for threads that are still running native code
4006 // + Delete this thread
4007 // + Call exit_globals()
4008 // > deletes tty
4009 // > deletes PerfMemory resources
4010 // + Return to caller
4011
4012 bool Threads::destroy_vm() {
4013 JavaThread* thread = JavaThread::current();
4014
4015 #ifdef ASSERT
4016 _vm_complete = false;
4017 #endif
4018 // Wait until we are the last non-daemon thread to execute
4019 { MutexLocker nu(Threads_lock);
4020 while (Threads::number_of_non_daemon_threads() > 1)
4021 // This wait should make safepoint checks, wait without a timeout,
4022 // and wait as a suspend-equivalent condition.
4023 //
4024 // Note: If the FlatProfiler is running and this thread is waiting
4025 // for another non-daemon thread to finish, then the FlatProfiler
4026 // is waiting for the external suspend request on this thread to
4027 // complete. wait_for_ext_suspend_completion() will eventually
4028 // timeout, but that takes time. Making this wait a suspend-
4029 // equivalent condition solves that timeout problem.
4030 //
4031 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4032 Mutex::_as_suspend_equivalent_flag);
4033 }
4034
4035 // Hang forever on exit if we are reporting an error.
4036 if (ShowMessageBoxOnError && is_error_reported()) {
4037 os::infinite_sleep();
4038 }
4039 os::wait_for_keypress_at_exit();
4040
4041 // run Java level shutdown hooks
4042 thread->invoke_shutdown_hooks();
4043
4044 before_exit(thread);
4045
4046 thread->exit(true);
4047
4048 // Stop VM thread.
4049 {
4050 // 4945125 The vm thread comes to a safepoint during exit.
4051 // GC vm_operations can get caught at the safepoint, and the
4052 // heap is unparseable if they are caught. Grab the Heap_lock
4053 // to prevent this. The GC vm_operations will not be able to
4054 // queue until after the vm thread is dead. After this point,
4055 // we'll never emerge out of the safepoint before the VM exits.
4056
4057 MutexLocker ml(Heap_lock);
4058
4059 VMThread::wait_for_vm_thread_exit();
4060 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4061 VMThread::destroy();
4062 }
4063
4064 // clean up ideal graph printers
4065 #if defined(COMPILER2) && !defined(PRODUCT)
4066 IdealGraphPrinter::clean_up();
4067 #endif
4068
4069 // Now, all Java threads are gone except daemon threads. Daemon threads
4070 // running Java code or in VM are stopped by the Safepoint. However,
4071 // daemon threads executing native code are still running. But they
4072 // will be stopped at native=>Java/VM barriers. Note that we can't
4073 // simply kill or suspend them, as it is inherently deadlock-prone.
4074
4075 VM_Exit::set_vm_exited();
4076
4077 notify_vm_shutdown();
4078
4079 delete thread;
4080
4081 #if INCLUDE_JVMCI
4082 if (JVMCICounterSize > 0) {
4083 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4084 }
4085 #endif
4086
4087 // exit_globals() will delete tty
4088 exit_globals();
4089
4090 LogConfiguration::finalize();
4091
4092 return true;
4093 }
4094
4095
4096 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4097 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4098 return is_supported_jni_version(version);
4099 }
4100
4101
4102 jboolean Threads::is_supported_jni_version(jint version) {
4103 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4104 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4105 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4106 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4107 if (version == JNI_VERSION_9) return JNI_TRUE;
4108 return JNI_FALSE;
4109 }
4110
4111
4112 void Threads::add(JavaThread* p, bool force_daemon) {
4113 // The threads lock must be owned at this point
4114 assert_locked_or_safepoint(Threads_lock);
4115
4116 // See the comment for this method in thread.hpp for its purpose and
4117 // why it is called here.
4118 p->initialize_queues();
4119 p->set_next(_thread_list);
4120 _thread_list = p;
4121 _number_of_threads++;
4122 oop threadObj = p->threadObj();
4123 bool daemon = true;
4124 // Bootstrapping problem: threadObj can be null for initial
4125 // JavaThread (or for threads attached via JNI)
4126 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4127 _number_of_non_daemon_threads++;
4128 daemon = false;
4129 }
4130
4131 ThreadService::add_thread(p, daemon);
4132
4133 // Possible GC point.
4134 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4135 }
4136
4137 void Threads::remove(JavaThread* p) {
4138 // Extra scope needed for Thread_lock, so we can check
4139 // that we do not remove thread without safepoint code notice
4140 { MutexLocker ml(Threads_lock);
4141
4142 assert(includes(p), "p must be present");
4143
4144 JavaThread* current = _thread_list;
4145 JavaThread* prev = NULL;
4146
4147 while (current != p) {
4148 prev = current;
4149 current = current->next();
4150 }
4151
4152 if (prev) {
4153 prev->set_next(current->next());
4154 } else {
4155 _thread_list = p->next();
4156 }
4157 _number_of_threads--;
4158 oop threadObj = p->threadObj();
4159 bool daemon = true;
4160 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4161 _number_of_non_daemon_threads--;
4162 daemon = false;
4163
4164 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4165 // on destroy_vm will wake up.
4166 if (number_of_non_daemon_threads() == 1) {
4167 Threads_lock->notify_all();
4168 }
4169 }
4170 ThreadService::remove_thread(p, daemon);
4171
4172 // Make sure that safepoint code disregard this thread. This is needed since
4173 // the thread might mess around with locks after this point. This can cause it
4174 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4175 // of this thread since it is removed from the queue.
4176 p->set_terminated_value();
4177 } // unlock Threads_lock
4178
4179 // Since Events::log uses a lock, we grab it outside the Threads_lock
4180 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4181 }
4182
4183 // Threads_lock must be held when this is called (or must be called during a safepoint)
4184 bool Threads::includes(JavaThread* p) {
4185 assert(Threads_lock->is_locked(), "sanity check");
4186 ALL_JAVA_THREADS(q) {
4187 if (q == p) {
4188 return true;
4189 }
4190 }
4191 return false;
4192 }
4193
4194 // Operations on the Threads list for GC. These are not explicitly locked,
4195 // but the garbage collector must provide a safe context for them to run.
4196 // In particular, these things should never be called when the Threads_lock
4197 // is held by some other thread. (Note: the Safepoint abstraction also
4198 // uses the Threads_lock to guarantee this property. It also makes sure that
4199 // all threads gets blocked when exiting or starting).
4200
4201 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4202 ALL_JAVA_THREADS(p) {
4203 p->oops_do(f, cld_f, cf);
4204 }
4205 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4206 }
4207
4208 void Threads::change_thread_claim_parity() {
4209 // Set the new claim parity.
4210 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4211 "Not in range.");
4212 _thread_claim_parity++;
4213 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4214 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4215 "Not in range.");
4216 }
4217
4218 #ifdef ASSERT
4219 void Threads::assert_all_threads_claimed() {
4220 ALL_JAVA_THREADS(p) {
4221 const int thread_parity = p->oops_do_parity();
4222 assert((thread_parity == _thread_claim_parity),
4223 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4224 }
4225 }
4226 #endif // ASSERT
4227
4228 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4229 int cp = Threads::thread_claim_parity();
4230 ALL_JAVA_THREADS(p) {
4231 if (p->claim_oops_do(is_par, cp)) {
4232 p->oops_do(f, cld_f, cf);
4233 }
4234 }
4235 VMThread* vmt = VMThread::vm_thread();
4236 if (vmt->claim_oops_do(is_par, cp)) {
4237 vmt->oops_do(f, cld_f, cf);
4238 }
4239 }
4240
4241 #if INCLUDE_ALL_GCS
4242 // Used by ParallelScavenge
4243 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4244 ALL_JAVA_THREADS(p) {
4245 q->enqueue(new ThreadRootsTask(p));
4246 }
4247 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4248 }
4249
4250 // Used by Parallel Old
4251 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4252 ALL_JAVA_THREADS(p) {
4253 q->enqueue(new ThreadRootsMarkingTask(p));
4254 }
4255 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4256 }
4257 #endif // INCLUDE_ALL_GCS
4258
4259 void Threads::nmethods_do(CodeBlobClosure* cf) {
4260 ALL_JAVA_THREADS(p) {
4261 p->nmethods_do(cf);
4262 }
4263 VMThread::vm_thread()->nmethods_do(cf);
4264 }
4265
4266 void Threads::metadata_do(void f(Metadata*)) {
4267 ALL_JAVA_THREADS(p) {
4268 p->metadata_do(f);
4269 }
4270 }
4271
4272 class ThreadHandlesClosure : public ThreadClosure {
4273 void (*_f)(Metadata*);
4274 public:
4275 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4276 virtual void do_thread(Thread* thread) {
4277 thread->metadata_handles_do(_f);
4278 }
4279 };
4280
4281 void Threads::metadata_handles_do(void f(Metadata*)) {
4282 // Only walk the Handles in Thread.
4283 ThreadHandlesClosure handles_closure(f);
4284 threads_do(&handles_closure);
4285 }
4286
4287 void Threads::deoptimized_wrt_marked_nmethods() {
4288 ALL_JAVA_THREADS(p) {
4289 p->deoptimized_wrt_marked_nmethods();
4290 }
4291 }
4292
4293
4294 // Get count Java threads that are waiting to enter the specified monitor.
4295 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4296 address monitor,
4297 bool doLock) {
4298 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4299 "must grab Threads_lock or be at safepoint");
4300 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4301
4302 int i = 0;
4303 {
4304 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4305 ALL_JAVA_THREADS(p) {
4306 if (!p->can_call_java()) continue;
4307
4308 address pending = (address)p->current_pending_monitor();
4309 if (pending == monitor) { // found a match
4310 if (i < count) result->append(p); // save the first count matches
4311 i++;
4312 }
4313 }
4314 }
4315 return result;
4316 }
4317
4318
4319 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4320 bool doLock) {
4321 assert(doLock ||
4322 Threads_lock->owned_by_self() ||
4323 SafepointSynchronize::is_at_safepoint(),
4324 "must grab Threads_lock or be at safepoint");
4325
4326 // NULL owner means not locked so we can skip the search
4327 if (owner == NULL) return NULL;
4328
4329 {
4330 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4331 ALL_JAVA_THREADS(p) {
4332 // first, see if owner is the address of a Java thread
4333 if (owner == (address)p) return p;
4334 }
4335 }
4336 // Cannot assert on lack of success here since this function may be
4337 // used by code that is trying to report useful problem information
4338 // like deadlock detection.
4339 if (UseHeavyMonitors) return NULL;
4340
4341 // If we didn't find a matching Java thread and we didn't force use of
4342 // heavyweight monitors, then the owner is the stack address of the
4343 // Lock Word in the owning Java thread's stack.
4344 //
4345 JavaThread* the_owner = NULL;
4346 {
4347 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4348 ALL_JAVA_THREADS(q) {
4349 if (q->is_lock_owned(owner)) {
4350 the_owner = q;
4351 break;
4352 }
4353 }
4354 }
4355 // cannot assert on lack of success here; see above comment
4356 return the_owner;
4357 }
4358
4359 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4360 void Threads::print_on(outputStream* st, bool print_stacks,
4361 bool internal_format, bool print_concurrent_locks) {
4362 char buf[32];
4363 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4364
4365 st->print_cr("Full thread dump %s (%s %s):",
4366 Abstract_VM_Version::vm_name(),
4367 Abstract_VM_Version::vm_release(),
4368 Abstract_VM_Version::vm_info_string());
4369 st->cr();
4370
4371 #if INCLUDE_SERVICES
4372 // Dump concurrent locks
4373 ConcurrentLocksDump concurrent_locks;
4374 if (print_concurrent_locks) {
4375 concurrent_locks.dump_at_safepoint();
4376 }
4377 #endif // INCLUDE_SERVICES
4378
4379 ALL_JAVA_THREADS(p) {
4380 ResourceMark rm;
4381 p->print_on(st);
4382 if (print_stacks) {
4383 if (internal_format) {
4384 p->trace_stack();
4385 } else {
4386 p->print_stack_on(st);
4387 }
4388 }
4389 st->cr();
4390 #if INCLUDE_SERVICES
4391 if (print_concurrent_locks) {
4392 concurrent_locks.print_locks_on(p, st);
4393 }
4394 #endif // INCLUDE_SERVICES
4395 }
4396
4397 VMThread::vm_thread()->print_on(st);
4398 st->cr();
4399 Universe::heap()->print_gc_threads_on(st);
4400 WatcherThread* wt = WatcherThread::watcher_thread();
4401 if (wt != NULL) {
4402 wt->print_on(st);
4403 st->cr();
4404 }
4405 st->flush();
4406 }
4407
4408 // Threads::print_on_error() is called by fatal error handler. It's possible
4409 // that VM is not at safepoint and/or current thread is inside signal handler.
4410 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4411 // memory (even in resource area), it might deadlock the error handler.
4412 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4413 int buflen) {
4414 bool found_current = false;
4415 st->print_cr("Java Threads: ( => current thread )");
4416 ALL_JAVA_THREADS(thread) {
4417 bool is_current = (current == thread);
4418 found_current = found_current || is_current;
4419
4420 st->print("%s", is_current ? "=>" : " ");
4421
4422 st->print(PTR_FORMAT, p2i(thread));
4423 st->print(" ");
4424 thread->print_on_error(st, buf, buflen);
4425 st->cr();
4426 }
4427 st->cr();
4428
4429 st->print_cr("Other Threads:");
4430 if (VMThread::vm_thread()) {
4431 bool is_current = (current == VMThread::vm_thread());
4432 found_current = found_current || is_current;
4433 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4434
4435 st->print(PTR_FORMAT, p2i(VMThread::vm_thread()));
4436 st->print(" ");
4437 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4438 st->cr();
4439 }
4440 WatcherThread* wt = WatcherThread::watcher_thread();
4441 if (wt != NULL) {
4442 bool is_current = (current == wt);
4443 found_current = found_current || is_current;
4444 st->print("%s", is_current ? "=>" : " ");
4445
4446 st->print(PTR_FORMAT, p2i(wt));
4447 st->print(" ");
4448 wt->print_on_error(st, buf, buflen);
4449 st->cr();
4450 }
4451 if (!found_current) {
4452 st->cr();
4453 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4454 current->print_on_error(st, buf, buflen);
4455 st->cr();
4456 }
4457 st->cr();
4458 st->print_cr("Threads with active compile tasks:");
4459 print_threads_compiling(st, buf, buflen);
4460 }
4461
4462 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) {
4463 ALL_JAVA_THREADS(thread) {
4464 if (thread->is_Compiler_thread()) {
4465 CompilerThread* ct = (CompilerThread*) thread;
4466 if (ct->task() != NULL) {
4467 thread->print_name_on_error(st, buf, buflen);
4468 ct->task()->print(st, NULL, true, true);
4469 }
4470 }
4471 }
4472 }
4473
4474
4475 // Internal SpinLock and Mutex
4476 // Based on ParkEvent
4477
4478 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4479 //
4480 // We employ SpinLocks _only for low-contention, fixed-length
4481 // short-duration critical sections where we're concerned
4482 // about native mutex_t or HotSpot Mutex:: latency.
4483 // The mux construct provides a spin-then-block mutual exclusion
4484 // mechanism.
4485 //
4486 // Testing has shown that contention on the ListLock guarding gFreeList
4487 // is common. If we implement ListLock as a simple SpinLock it's common
4488 // for the JVM to devolve to yielding with little progress. This is true
4489 // despite the fact that the critical sections protected by ListLock are
4490 // extremely short.
4491 //
4492 // TODO-FIXME: ListLock should be of type SpinLock.
4493 // We should make this a 1st-class type, integrated into the lock
4494 // hierarchy as leaf-locks. Critically, the SpinLock structure
4495 // should have sufficient padding to avoid false-sharing and excessive
4496 // cache-coherency traffic.
4497
4498
4499 typedef volatile int SpinLockT;
4500
4501 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4502 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4503 return; // normal fast-path return
4504 }
4505
4506 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4507 TEVENT(SpinAcquire - ctx);
4508 int ctr = 0;
4509 int Yields = 0;
4510 for (;;) {
4511 while (*adr != 0) {
4512 ++ctr;
4513 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4514 if (Yields > 5) {
4515 os::naked_short_sleep(1);
4516 } else {
4517 os::naked_yield();
4518 ++Yields;
4519 }
4520 } else {
4521 SpinPause();
4522 }
4523 }
4524 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4525 }
4526 }
4527
4528 void Thread::SpinRelease(volatile int * adr) {
4529 assert(*adr != 0, "invariant");
4530 OrderAccess::fence(); // guarantee at least release consistency.
4531 // Roach-motel semantics.
4532 // It's safe if subsequent LDs and STs float "up" into the critical section,
4533 // but prior LDs and STs within the critical section can't be allowed
4534 // to reorder or float past the ST that releases the lock.
4535 // Loads and stores in the critical section - which appear in program
4536 // order before the store that releases the lock - must also appear
4537 // before the store that releases the lock in memory visibility order.
4538 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4539 // the ST of 0 into the lock-word which releases the lock, so fence
4540 // more than covers this on all platforms.
4541 *adr = 0;
4542 }
4543
4544 // muxAcquire and muxRelease:
4545 //
4546 // * muxAcquire and muxRelease support a single-word lock-word construct.
4547 // The LSB of the word is set IFF the lock is held.
4548 // The remainder of the word points to the head of a singly-linked list
4549 // of threads blocked on the lock.
4550 //
4551 // * The current implementation of muxAcquire-muxRelease uses its own
4552 // dedicated Thread._MuxEvent instance. If we're interested in
4553 // minimizing the peak number of extant ParkEvent instances then
4554 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4555 // as certain invariants were satisfied. Specifically, care would need
4556 // to be taken with regards to consuming unpark() "permits".
4557 // A safe rule of thumb is that a thread would never call muxAcquire()
4558 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4559 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4560 // consume an unpark() permit intended for monitorenter, for instance.
4561 // One way around this would be to widen the restricted-range semaphore
4562 // implemented in park(). Another alternative would be to provide
4563 // multiple instances of the PlatformEvent() for each thread. One
4564 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4565 //
4566 // * Usage:
4567 // -- Only as leaf locks
4568 // -- for short-term locking only as muxAcquire does not perform
4569 // thread state transitions.
4570 //
4571 // Alternatives:
4572 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4573 // but with parking or spin-then-park instead of pure spinning.
4574 // * Use Taura-Oyama-Yonenzawa locks.
4575 // * It's possible to construct a 1-0 lock if we encode the lockword as
4576 // (List,LockByte). Acquire will CAS the full lockword while Release
4577 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4578 // acquiring threads use timers (ParkTimed) to detect and recover from
4579 // the stranding window. Thread/Node structures must be aligned on 256-byte
4580 // boundaries by using placement-new.
4581 // * Augment MCS with advisory back-link fields maintained with CAS().
4582 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4583 // The validity of the backlinks must be ratified before we trust the value.
4584 // If the backlinks are invalid the exiting thread must back-track through the
4585 // the forward links, which are always trustworthy.
4586 // * Add a successor indication. The LockWord is currently encoded as
4587 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4588 // to provide the usual futile-wakeup optimization.
4589 // See RTStt for details.
4590 // * Consider schedctl.sc_nopreempt to cover the critical section.
4591 //
4592
4593
4594 typedef volatile intptr_t MutexT; // Mux Lock-word
4595 enum MuxBits { LOCKBIT = 1 };
4596
4597 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4598 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4599 if (w == 0) return;
4600 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4601 return;
4602 }
4603
4604 TEVENT(muxAcquire - Contention);
4605 ParkEvent * const Self = Thread::current()->_MuxEvent;
4606 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4607 for (;;) {
4608 int its = (os::is_MP() ? 100 : 0) + 1;
4609
4610 // Optional spin phase: spin-then-park strategy
4611 while (--its >= 0) {
4612 w = *Lock;
4613 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4614 return;
4615 }
4616 }
4617
4618 Self->reset();
4619 Self->OnList = intptr_t(Lock);
4620 // The following fence() isn't _strictly necessary as the subsequent
4621 // CAS() both serializes execution and ratifies the fetched *Lock value.
4622 OrderAccess::fence();
4623 for (;;) {
4624 w = *Lock;
4625 if ((w & LOCKBIT) == 0) {
4626 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4627 Self->OnList = 0; // hygiene - allows stronger asserts
4628 return;
4629 }
4630 continue; // Interference -- *Lock changed -- Just retry
4631 }
4632 assert(w & LOCKBIT, "invariant");
4633 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4634 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4635 }
4636
4637 while (Self->OnList != 0) {
4638 Self->park();
4639 }
4640 }
4641 }
4642
4643 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4644 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4645 if (w == 0) return;
4646 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4647 return;
4648 }
4649
4650 TEVENT(muxAcquire - Contention);
4651 ParkEvent * ReleaseAfter = NULL;
4652 if (ev == NULL) {
4653 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4654 }
4655 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4656 for (;;) {
4657 guarantee(ev->OnList == 0, "invariant");
4658 int its = (os::is_MP() ? 100 : 0) + 1;
4659
4660 // Optional spin phase: spin-then-park strategy
4661 while (--its >= 0) {
4662 w = *Lock;
4663 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4664 if (ReleaseAfter != NULL) {
4665 ParkEvent::Release(ReleaseAfter);
4666 }
4667 return;
4668 }
4669 }
4670
4671 ev->reset();
4672 ev->OnList = intptr_t(Lock);
4673 // The following fence() isn't _strictly necessary as the subsequent
4674 // CAS() both serializes execution and ratifies the fetched *Lock value.
4675 OrderAccess::fence();
4676 for (;;) {
4677 w = *Lock;
4678 if ((w & LOCKBIT) == 0) {
4679 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4680 ev->OnList = 0;
4681 // We call ::Release while holding the outer lock, thus
4682 // artificially lengthening the critical section.
4683 // Consider deferring the ::Release() until the subsequent unlock(),
4684 // after we've dropped the outer lock.
4685 if (ReleaseAfter != NULL) {
4686 ParkEvent::Release(ReleaseAfter);
4687 }
4688 return;
4689 }
4690 continue; // Interference -- *Lock changed -- Just retry
4691 }
4692 assert(w & LOCKBIT, "invariant");
4693 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4694 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4695 }
4696
4697 while (ev->OnList != 0) {
4698 ev->park();
4699 }
4700 }
4701 }
4702
4703 // Release() must extract a successor from the list and then wake that thread.
4704 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4705 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4706 // Release() would :
4707 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4708 // (B) Extract a successor from the private list "in-hand"
4709 // (C) attempt to CAS() the residual back into *Lock over null.
4710 // If there were any newly arrived threads and the CAS() would fail.
4711 // In that case Release() would detach the RATs, re-merge the list in-hand
4712 // with the RATs and repeat as needed. Alternately, Release() might
4713 // detach and extract a successor, but then pass the residual list to the wakee.
4714 // The wakee would be responsible for reattaching and remerging before it
4715 // competed for the lock.
4716 //
4717 // Both "pop" and DMR are immune from ABA corruption -- there can be
4718 // multiple concurrent pushers, but only one popper or detacher.
4719 // This implementation pops from the head of the list. This is unfair,
4720 // but tends to provide excellent throughput as hot threads remain hot.
4721 // (We wake recently run threads first).
4722 //
4723 // All paths through muxRelease() will execute a CAS.
4724 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4725 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4726 // executed within the critical section are complete and globally visible before the
4727 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4728 void Thread::muxRelease(volatile intptr_t * Lock) {
4729 for (;;) {
4730 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4731 assert(w & LOCKBIT, "invariant");
4732 if (w == LOCKBIT) return;
4733 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4734 assert(List != NULL, "invariant");
4735 assert(List->OnList == intptr_t(Lock), "invariant");
4736 ParkEvent * const nxt = List->ListNext;
4737 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4738
4739 // The following CAS() releases the lock and pops the head element.
4740 // The CAS() also ratifies the previously fetched lock-word value.
4741 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4742 continue;
4743 }
4744 List->OnList = 0;
4745 OrderAccess::fence();
4746 List->unpark();
4747 return;
4748 }
4749 }
4750
4751
4752 void Threads::verify() {
4753 ALL_JAVA_THREADS(p) {
4754 p->verify();
4755 }
4756 VMThread* thread = VMThread::vm_thread();
4757 if (thread != NULL) thread->verify();
4758 }