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