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