1 /*
2 * Copyright (c) 1997, 2020, 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 "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classLoader.hpp"
29 #include "classfile/javaClasses.hpp"
30 #include "classfile/moduleEntry.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "code/codeCache.hpp"
34 #include "code/scopeDesc.hpp"
35 #include "compiler/compileBroker.hpp"
36 #include "compiler/compileTask.hpp"
37 #include "gc/shared/barrierSet.hpp"
38 #include "gc/shared/gcId.hpp"
39 #include "gc/shared/gcLocker.inline.hpp"
40 #include "gc/shared/workgroup.hpp"
41 #include "interpreter/interpreter.hpp"
42 #include "interpreter/linkResolver.hpp"
43 #include "interpreter/oopMapCache.hpp"
44 #include "jfr/jfrEvents.hpp"
45 #include "jvmtifiles/jvmtiEnv.hpp"
46 #include "logging/log.hpp"
47 #include "logging/logConfiguration.hpp"
48 #include "logging/logStream.hpp"
49 #include "memory/allocation.inline.hpp"
50 #include "memory/iterator.hpp"
51 #include "memory/metaspaceShared.hpp"
52 #include "memory/oopFactory.hpp"
53 #include "memory/resourceArea.hpp"
54 #include "memory/universe.hpp"
55 #include "oops/access.inline.hpp"
56 #include "oops/instanceKlass.hpp"
57 #include "oops/objArrayOop.hpp"
58 #include "oops/oop.inline.hpp"
59 #include "oops/symbol.hpp"
60 #include "oops/typeArrayOop.inline.hpp"
61 #include "oops/verifyOopClosure.hpp"
62 #include "prims/jvm_misc.hpp"
63 #include "prims/jvmtiExport.hpp"
64 #include "prims/jvmtiThreadState.hpp"
65 #include "runtime/arguments.hpp"
66 #include "runtime/atomic.hpp"
67 #include "runtime/biasedLocking.hpp"
68 #include "runtime/fieldDescriptor.inline.hpp"
69 #include "runtime/deoptimization.hpp"
70 #include "runtime/frame.inline.hpp"
71 #include "runtime/handles.inline.hpp"
72 #include "runtime/handshake.hpp"
73 #include "runtime/init.hpp"
74 #include "runtime/interfaceSupport.inline.hpp"
75 #include "runtime/java.hpp"
76 #include "runtime/javaCalls.hpp"
77 #include "runtime/jniHandles.inline.hpp"
78 #include "runtime/jniPeriodicChecker.hpp"
79 #include "runtime/memprofiler.hpp"
80 #include "runtime/mutexLocker.hpp"
81 #include "runtime/objectMonitor.hpp"
82 #include "runtime/orderAccess.hpp"
83 #include "runtime/osThread.hpp"
84 #include "runtime/prefetch.inline.hpp"
85 #include "runtime/safepoint.hpp"
86 #include "runtime/safepointMechanism.inline.hpp"
87 #include "runtime/safepointVerifiers.hpp"
88 #include "runtime/serviceThread.hpp"
89 #include "runtime/sharedRuntime.hpp"
90 #include "runtime/statSampler.hpp"
91 #include "runtime/stubRoutines.hpp"
92 #include "runtime/sweeper.hpp"
93 #include "runtime/task.hpp"
94 #include "runtime/thread.inline.hpp"
95 #include "runtime/threadCritical.hpp"
96 #include "runtime/threadSMR.inline.hpp"
97 #include "runtime/threadStatisticalInfo.hpp"
98 #include "runtime/timer.hpp"
99 #include "runtime/timerTrace.hpp"
100 #include "runtime/vframe.inline.hpp"
101 #include "runtime/vframeArray.hpp"
102 #include "runtime/vframe_hp.hpp"
103 #include "runtime/vmThread.hpp"
104 #include "runtime/vmOperations.hpp"
105 #include "runtime/vm_version.hpp"
106 #include "services/attachListener.hpp"
107 #include "services/management.hpp"
108 #include "services/memTracker.hpp"
109 #include "services/threadService.hpp"
110 #include "utilities/align.hpp"
111 #include "utilities/copy.hpp"
112 #include "utilities/defaultStream.hpp"
113 #include "utilities/dtrace.hpp"
114 #include "utilities/events.hpp"
115 #include "utilities/macros.hpp"
116 #include "utilities/preserveException.hpp"
117 #include "utilities/singleWriterSynchronizer.hpp"
118 #include "utilities/vmError.hpp"
119 #if INCLUDE_JVMCI
120 #include "jvmci/jvmci.hpp"
121 #include "jvmci/jvmciEnv.hpp"
122 #endif
123 #ifdef COMPILER1
124 #include "c1/c1_Compiler.hpp"
125 #endif
126 #ifdef COMPILER2
127 #include "opto/c2compiler.hpp"
128 #include "opto/idealGraphPrinter.hpp"
129 #endif
130 #if INCLUDE_RTM_OPT
131 #include "runtime/rtmLocking.hpp"
132 #endif
133 #if INCLUDE_JFR
134 #include "jfr/jfr.hpp"
135 #endif
136
137 // Initialization after module runtime initialization
138 void universe_post_module_init(); // must happen after call_initPhase2
139
140 #ifdef DTRACE_ENABLED
141
142 // Only bother with this argument setup if dtrace is available
143
144 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
145 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
146
147 #define DTRACE_THREAD_PROBE(probe, javathread) \
148 { \
149 ResourceMark rm(this); \
150 int len = 0; \
151 const char* name = (javathread)->get_thread_name(); \
152 len = strlen(name); \
153 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
154 (char *) name, len, \
155 java_lang_Thread::thread_id((javathread)->threadObj()), \
156 (uintptr_t) (javathread)->osthread()->thread_id(), \
157 java_lang_Thread::is_daemon((javathread)->threadObj())); \
158 }
159
160 #else // ndef DTRACE_ENABLED
161
162 #define DTRACE_THREAD_PROBE(probe, javathread)
163
164 #endif // ndef DTRACE_ENABLED
165
166 #ifndef USE_LIBRARY_BASED_TLS_ONLY
167 // Current thread is maintained as a thread-local variable
168 THREAD_LOCAL Thread* Thread::_thr_current = NULL;
169 #endif
170
171 // ======= Thread ========
172 // Support for forcing alignment of thread objects for biased locking
173 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
174 if (UseBiasedLocking) {
175 const size_t alignment = markWord::biased_lock_alignment;
176 size_t aligned_size = size + (alignment - sizeof(intptr_t));
177 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
178 : AllocateHeap(aligned_size, flags, CURRENT_PC,
179 AllocFailStrategy::RETURN_NULL);
180 void* aligned_addr = align_up(real_malloc_addr, alignment);
181 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
182 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
183 "JavaThread alignment code overflowed allocated storage");
184 if (aligned_addr != real_malloc_addr) {
185 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
186 p2i(real_malloc_addr),
187 p2i(aligned_addr));
188 }
189 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
190 return aligned_addr;
191 } else {
192 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
193 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
194 }
195 }
196
197 void Thread::operator delete(void* p) {
198 if (UseBiasedLocking) {
199 FreeHeap(((Thread*) p)->_real_malloc_address);
200 } else {
201 FreeHeap(p);
202 }
203 }
204
205 void JavaThread::smr_delete() {
206 if (_on_thread_list) {
207 ThreadsSMRSupport::smr_delete(this);
208 } else {
209 delete this;
210 }
211 }
212
213 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
214 // JavaThread
215
216 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
217
218 Thread::Thread() {
219
220 DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
221
222 // stack and get_thread
223 set_stack_base(NULL);
224 set_stack_size(0);
225 set_lgrp_id(-1);
226 DEBUG_ONLY(clear_suspendible_thread();)
227
228 // allocated data structures
229 set_osthread(NULL);
230 set_resource_area(new (mtThread)ResourceArea());
231 DEBUG_ONLY(_current_resource_mark = NULL;)
232 set_handle_area(new (mtThread) HandleArea(NULL));
233 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
234 set_active_handles(NULL);
235 set_free_handle_block(NULL);
236 set_last_handle_mark(NULL);
237 DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
238
239 // Initial value of zero ==> never claimed.
240 _threads_do_token = 0;
241 _threads_hazard_ptr = NULL;
242 _threads_list_ptr = NULL;
243 _nested_threads_hazard_ptr_cnt = 0;
244 _rcu_counter = 0;
245
246 // the handle mark links itself to last_handle_mark
247 new HandleMark(this);
248
249 // plain initialization
250 debug_only(_owned_locks = NULL;)
251 NOT_PRODUCT(_no_safepoint_count = 0;)
252 NOT_PRODUCT(_skip_gcalot = false;)
253 _jvmti_env_iteration_count = 0;
254 set_allocated_bytes(0);
255 _vm_operation_started_count = 0;
256 _vm_operation_completed_count = 0;
257 _current_pending_monitor = NULL;
258 _current_pending_monitor_is_from_java = true;
259 _current_waiting_monitor = NULL;
260 _current_pending_raw_monitor = NULL;
261 _num_nested_signal = 0;
262 om_free_list = NULL;
263 om_free_count = 0;
264 om_free_provision = 32;
265 om_in_use_list = NULL;
266 om_in_use_count = 0;
267
268 #ifdef ASSERT
269 _visited_for_critical_count = false;
270 #endif
271
272 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
273 Monitor::_safepoint_check_sometimes);
274 _suspend_flags = 0;
275
276 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
277 _hashStateX = os::random();
278 _hashStateY = 842502087;
279 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
280 _hashStateW = 273326509;
281
282 _OnTrap = 0;
283 _Stalled = 0;
284 _TypeTag = 0x2BAD;
285
286 // Many of the following fields are effectively final - immutable
287 // Note that nascent threads can't use the Native Monitor-Mutex
288 // construct until the _MutexEvent is initialized ...
289 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
290 // we might instead use a stack of ParkEvents that we could provision on-demand.
291 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
292 // and ::Release()
293 _ParkEvent = ParkEvent::Allocate(this);
294 _MuxEvent = ParkEvent::Allocate(this);
295
296 #ifdef CHECK_UNHANDLED_OOPS
297 if (CheckUnhandledOops) {
298 _unhandled_oops = new UnhandledOops(this);
299 }
300 #endif // CHECK_UNHANDLED_OOPS
301 #ifdef ASSERT
302 if (UseBiasedLocking) {
303 assert(is_aligned(this, markWord::biased_lock_alignment), "forced alignment of thread object failed");
304 assert(this == _real_malloc_address ||
305 this == align_up(_real_malloc_address, markWord::biased_lock_alignment),
306 "bug in forced alignment of thread objects");
307 }
308 #endif // ASSERT
309
310 // Notify the barrier set that a thread is being created. The initial
311 // thread is created before the barrier set is available. The call to
312 // BarrierSet::on_thread_create() for this thread is therefore deferred
313 // to BarrierSet::set_barrier_set().
314 BarrierSet* const barrier_set = BarrierSet::barrier_set();
315 if (barrier_set != NULL) {
316 barrier_set->on_thread_create(this);
317 } else {
318 // Only the main thread should be created before the barrier set
319 // and that happens just before Thread::current is set. No other thread
320 // can attach as the VM is not created yet, so they can't execute this code.
321 // If the main thread creates other threads before the barrier set that is an error.
322 assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
323 }
324 }
325
326 void Thread::initialize_thread_current() {
327 #ifndef USE_LIBRARY_BASED_TLS_ONLY
328 assert(_thr_current == NULL, "Thread::current already initialized");
329 _thr_current = this;
330 #endif
331 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
332 ThreadLocalStorage::set_thread(this);
333 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
334 }
335
336 void Thread::clear_thread_current() {
337 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
338 #ifndef USE_LIBRARY_BASED_TLS_ONLY
339 _thr_current = NULL;
340 #endif
341 ThreadLocalStorage::set_thread(NULL);
342 }
343
344 void Thread::record_stack_base_and_size() {
345 // Note: at this point, Thread object is not yet initialized. Do not rely on
346 // any members being initialized. Do not rely on Thread::current() being set.
347 // If possible, refrain from doing anything which may crash or assert since
348 // quite probably those crash dumps will be useless.
349 set_stack_base(os::current_stack_base());
350 set_stack_size(os::current_stack_size());
351
352 #ifdef SOLARIS
353 if (os::is_primordial_thread()) {
354 os::Solaris::correct_stack_boundaries_for_primordial_thread(this);
355 }
356 #endif
357
358 // Set stack limits after thread is initialized.
359 if (is_Java_thread()) {
360 ((JavaThread*) this)->set_stack_overflow_limit();
361 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
362 }
363 }
364
365 #if INCLUDE_NMT
366 void Thread::register_thread_stack_with_NMT() {
367 MemTracker::record_thread_stack(stack_end(), stack_size());
368 }
369 #endif // INCLUDE_NMT
370
371 void Thread::call_run() {
372 DEBUG_ONLY(_run_state = CALL_RUN;)
373
374 // At this point, Thread object should be fully initialized and
375 // Thread::current() should be set.
376
377 assert(Thread::current_or_null() != NULL, "current thread is unset");
378 assert(Thread::current_or_null() == this, "current thread is wrong");
379
380 // Perform common initialization actions
381
382 register_thread_stack_with_NMT();
383
384 JFR_ONLY(Jfr::on_thread_start(this);)
385
386 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
387 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
388 os::current_thread_id(), p2i(stack_end()),
389 p2i(stack_base()), stack_size()/1024);
390
391 // Perform <ChildClass> initialization actions
392 DEBUG_ONLY(_run_state = PRE_RUN;)
393 this->pre_run();
394
395 // Invoke <ChildClass>::run()
396 DEBUG_ONLY(_run_state = RUN;)
397 this->run();
398 // Returned from <ChildClass>::run(). Thread finished.
399
400 // Perform common tear-down actions
401
402 assert(Thread::current_or_null() != NULL, "current thread is unset");
403 assert(Thread::current_or_null() == this, "current thread is wrong");
404
405 // Perform <ChildClass> tear-down actions
406 DEBUG_ONLY(_run_state = POST_RUN;)
407 this->post_run();
408
409 // Note: at this point the thread object may already have deleted itself,
410 // so from here on do not dereference *this*. Not all thread types currently
411 // delete themselves when they terminate. But no thread should ever be deleted
412 // asynchronously with respect to its termination - that is what _run_state can
413 // be used to check.
414
415 assert(Thread::current_or_null() == NULL, "current thread still present");
416 }
417
418 Thread::~Thread() {
419
420 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
421 // get started due to errors etc. Any active thread should at least reach post_run
422 // before it is deleted (usually in post_run()).
423 assert(_run_state == PRE_CALL_RUN ||
424 _run_state == POST_RUN, "Active Thread deleted before post_run(): "
425 "_run_state=%d", (int)_run_state);
426
427 // Notify the barrier set that a thread is being destroyed. Note that a barrier
428 // set might not be available if we encountered errors during bootstrapping.
429 BarrierSet* const barrier_set = BarrierSet::barrier_set();
430 if (barrier_set != NULL) {
431 barrier_set->on_thread_destroy(this);
432 }
433
434 // stack_base can be NULL if the thread is never started or exited before
435 // record_stack_base_and_size called. Although, we would like to ensure
436 // that all started threads do call record_stack_base_and_size(), there is
437 // not proper way to enforce that.
438 #if INCLUDE_NMT
439 if (_stack_base != NULL) {
440 MemTracker::release_thread_stack(stack_end(), stack_size());
441 #ifdef ASSERT
442 set_stack_base(NULL);
443 #endif
444 }
445 #endif // INCLUDE_NMT
446
447 // deallocate data structures
448 delete resource_area();
449 // since the handle marks are using the handle area, we have to deallocated the root
450 // handle mark before deallocating the thread's handle area,
451 assert(last_handle_mark() != NULL, "check we have an element");
452 delete last_handle_mark();
453 assert(last_handle_mark() == NULL, "check we have reached the end");
454
455 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
456 // We NULL out the fields for good hygiene.
457 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
458 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
459
460 delete handle_area();
461 delete metadata_handles();
462
463 // SR_handler uses this as a termination indicator -
464 // needs to happen before os::free_thread()
465 delete _SR_lock;
466 _SR_lock = NULL;
467
468 // osthread() can be NULL, if creation of thread failed.
469 if (osthread() != NULL) os::free_thread(osthread());
470
471 // Clear Thread::current if thread is deleting itself and it has not
472 // already been done. This must be done before the memory is deallocated.
473 // Needed to ensure JNI correctly detects non-attached threads.
474 if (this == Thread::current_or_null()) {
475 Thread::clear_thread_current();
476 }
477
478 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
479 }
480
481 #ifdef ASSERT
482 // A JavaThread is considered "dangling" if it is not the current
483 // thread, has been added the Threads list, the system is not at a
484 // safepoint and the Thread is not "protected".
485 //
486 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
487 assert(!thread->is_Java_thread() || Thread::current() == thread ||
488 !((JavaThread *) thread)->on_thread_list() ||
489 SafepointSynchronize::is_at_safepoint() ||
490 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
491 "possibility of dangling Thread pointer");
492 }
493 #endif
494
495 ThreadPriority Thread::get_priority(const Thread* const thread) {
496 ThreadPriority priority;
497 // Can return an error!
498 (void)os::get_priority(thread, priority);
499 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
500 return priority;
501 }
502
503 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
504 debug_only(check_for_dangling_thread_pointer(thread);)
505 // Can return an error!
506 (void)os::set_priority(thread, priority);
507 }
508
509
510 void Thread::start(Thread* thread) {
511 // Start is different from resume in that its safety is guaranteed by context or
512 // being called from a Java method synchronized on the Thread object.
513 if (!DisableStartThread) {
514 if (thread->is_Java_thread()) {
515 // Initialize the thread state to RUNNABLE before starting this thread.
516 // Can not set it after the thread started because we do not know the
517 // exact thread state at that time. It could be in MONITOR_WAIT or
518 // in SLEEPING or some other state.
519 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
520 java_lang_Thread::RUNNABLE);
521 }
522 os::start_thread(thread);
523 }
524 }
525
526 class InstallAsyncExceptionClosure : public HandshakeClosure {
527 Handle _throwable; // The Throwable thrown at the target Thread
528 public:
529 InstallAsyncExceptionClosure(Handle throwable) : HandshakeClosure("InstallAsyncException"), _throwable(throwable) {}
530
531 void do_thread(Thread* thr) {
532 JavaThread* target = (JavaThread*)thr;
533 // Note that this now allows multiple ThreadDeath exceptions to be
534 // thrown at a thread.
535 // The target thread has run and has not exited yet.
536 target->send_thread_stop(_throwable());
537 }
538 };
539
540 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
541 Handle throwable(Thread::current(), java_throwable);
542 JavaThread* target = java_lang_Thread::thread(java_thread);
543 InstallAsyncExceptionClosure vm_stop(throwable);
544 Handshake::execute(&vm_stop, target);
545 }
546
547
548 // Check if an external suspend request has completed (or has been
549 // cancelled). Returns true if the thread is externally suspended and
550 // false otherwise.
551 //
552 // The bits parameter returns information about the code path through
553 // the routine. Useful for debugging:
554 //
555 // set in is_ext_suspend_completed():
556 // 0x00000001 - routine was entered
557 // 0x00000010 - routine return false at end
558 // 0x00000100 - thread exited (return false)
559 // 0x00000200 - suspend request cancelled (return false)
560 // 0x00000400 - thread suspended (return true)
561 // 0x00001000 - thread is in a suspend equivalent state (return true)
562 // 0x00002000 - thread is native and walkable (return true)
563 // 0x00004000 - thread is native_trans and walkable (needed retry)
564 //
565 // set in wait_for_ext_suspend_completion():
566 // 0x00010000 - routine was entered
567 // 0x00020000 - suspend request cancelled before loop (return false)
568 // 0x00040000 - thread suspended before loop (return true)
569 // 0x00080000 - suspend request cancelled in loop (return false)
570 // 0x00100000 - thread suspended in loop (return true)
571 // 0x00200000 - suspend not completed during retry loop (return false)
572
573 // Helper class for tracing suspend wait debug bits.
574 //
575 // 0x00000100 indicates that the target thread exited before it could
576 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
577 // 0x00080000 each indicate a cancelled suspend request so they don't
578 // count as wait failures either.
579 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
580
581 class TraceSuspendDebugBits : public StackObj {
582 private:
583 JavaThread * jt;
584 bool is_wait;
585 bool called_by_wait; // meaningful when !is_wait
586 uint32_t * bits;
587
588 public:
589 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
590 uint32_t *_bits) {
591 jt = _jt;
592 is_wait = _is_wait;
593 called_by_wait = _called_by_wait;
594 bits = _bits;
595 }
596
597 ~TraceSuspendDebugBits() {
598 if (!is_wait) {
599 #if 1
600 // By default, don't trace bits for is_ext_suspend_completed() calls.
601 // That trace is very chatty.
602 return;
603 #else
604 if (!called_by_wait) {
605 // If tracing for is_ext_suspend_completed() is enabled, then only
606 // trace calls to it from wait_for_ext_suspend_completion()
607 return;
608 }
609 #endif
610 }
611
612 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
613 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
614 MutexLocker ml(Threads_lock); // needed for get_thread_name()
615 ResourceMark rm;
616
617 tty->print_cr(
618 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
619 jt->get_thread_name(), *bits);
620
621 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
622 }
623 }
624 }
625 };
626 #undef DEBUG_FALSE_BITS
627
628
629 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
630 uint32_t *bits) {
631 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
632
633 bool did_trans_retry = false; // only do thread_in_native_trans retry once
634 bool do_trans_retry; // flag to force the retry
635
636 *bits |= 0x00000001;
637
638 do {
639 do_trans_retry = false;
640
641 if (is_exiting()) {
642 // Thread is in the process of exiting. This is always checked
643 // first to reduce the risk of dereferencing a freed JavaThread.
644 *bits |= 0x00000100;
645 return false;
646 }
647
648 if (!is_external_suspend()) {
649 // Suspend request is cancelled. This is always checked before
650 // is_ext_suspended() to reduce the risk of a rogue resume
651 // confusing the thread that made the suspend request.
652 *bits |= 0x00000200;
653 return false;
654 }
655
656 if (is_ext_suspended()) {
657 // thread is suspended
658 *bits |= 0x00000400;
659 return true;
660 }
661
662 // Now that we no longer do hard suspends of threads running
663 // native code, the target thread can be changing thread state
664 // while we are in this routine:
665 //
666 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
667 //
668 // We save a copy of the thread state as observed at this moment
669 // and make our decision about suspend completeness based on the
670 // copy. This closes the race where the thread state is seen as
671 // _thread_in_native_trans in the if-thread_blocked check, but is
672 // seen as _thread_blocked in if-thread_in_native_trans check.
673 JavaThreadState save_state = thread_state();
674
675 if (save_state == _thread_blocked && is_suspend_equivalent()) {
676 // If the thread's state is _thread_blocked and this blocking
677 // condition is known to be equivalent to a suspend, then we can
678 // consider the thread to be externally suspended. This means that
679 // the code that sets _thread_blocked has been modified to do
680 // self-suspension if the blocking condition releases. We also
681 // used to check for CONDVAR_WAIT here, but that is now covered by
682 // the _thread_blocked with self-suspension check.
683 //
684 // Return true since we wouldn't be here unless there was still an
685 // external suspend request.
686 *bits |= 0x00001000;
687 return true;
688 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
689 // Threads running native code will self-suspend on native==>VM/Java
690 // transitions. If its stack is walkable (should always be the case
691 // unless this function is called before the actual java_suspend()
692 // call), then the wait is done.
693 *bits |= 0x00002000;
694 return true;
695 } else if (!called_by_wait && !did_trans_retry &&
696 save_state == _thread_in_native_trans &&
697 frame_anchor()->walkable()) {
698 // The thread is transitioning from thread_in_native to another
699 // thread state. check_safepoint_and_suspend_for_native_trans()
700 // will force the thread to self-suspend. If it hasn't gotten
701 // there yet we may have caught the thread in-between the native
702 // code check above and the self-suspend. Lucky us. If we were
703 // called by wait_for_ext_suspend_completion(), then it
704 // will be doing the retries so we don't have to.
705 //
706 // Since we use the saved thread state in the if-statement above,
707 // there is a chance that the thread has already transitioned to
708 // _thread_blocked by the time we get here. In that case, we will
709 // make a single unnecessary pass through the logic below. This
710 // doesn't hurt anything since we still do the trans retry.
711
712 *bits |= 0x00004000;
713
714 // Once the thread leaves thread_in_native_trans for another
715 // thread state, we break out of this retry loop. We shouldn't
716 // need this flag to prevent us from getting back here, but
717 // sometimes paranoia is good.
718 did_trans_retry = true;
719
720 // We wait for the thread to transition to a more usable state.
721 for (int i = 1; i <= SuspendRetryCount; i++) {
722 // We used to do an "os::yield_all(i)" call here with the intention
723 // that yielding would increase on each retry. However, the parameter
724 // is ignored on Linux which means the yield didn't scale up. Waiting
725 // on the SR_lock below provides a much more predictable scale up for
726 // the delay. It also provides a simple/direct point to check for any
727 // safepoint requests from the VMThread
728
729 // temporarily drops SR_lock while doing wait with safepoint check
730 // (if we're a JavaThread - the WatcherThread can also call this)
731 // and increase delay with each retry
732 if (Thread::current()->is_Java_thread()) {
733 SR_lock()->wait(i * delay);
734 } else {
735 SR_lock()->wait_without_safepoint_check(i * delay);
736 }
737
738 // check the actual thread state instead of what we saved above
739 if (thread_state() != _thread_in_native_trans) {
740 // the thread has transitioned to another thread state so
741 // try all the checks (except this one) one more time.
742 do_trans_retry = true;
743 break;
744 }
745 } // end retry loop
746
747
748 }
749 } while (do_trans_retry);
750
751 *bits |= 0x00000010;
752 return false;
753 }
754
755 // Wait for an external suspend request to complete (or be cancelled).
756 // Returns true if the thread is externally suspended and false otherwise.
757 //
758 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
759 uint32_t *bits) {
760 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
761 false /* !called_by_wait */, bits);
762
763 // local flag copies to minimize SR_lock hold time
764 bool is_suspended;
765 bool pending;
766 uint32_t reset_bits;
767
768 // set a marker so is_ext_suspend_completed() knows we are the caller
769 *bits |= 0x00010000;
770
771 // We use reset_bits to reinitialize the bits value at the top of
772 // each retry loop. This allows the caller to make use of any
773 // unused bits for their own marking purposes.
774 reset_bits = *bits;
775
776 {
777 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
778 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
779 delay, bits);
780 pending = is_external_suspend();
781 }
782 // must release SR_lock to allow suspension to complete
783
784 if (!pending) {
785 // A cancelled suspend request is the only false return from
786 // is_ext_suspend_completed() that keeps us from entering the
787 // retry loop.
788 *bits |= 0x00020000;
789 return false;
790 }
791
792 if (is_suspended) {
793 *bits |= 0x00040000;
794 return true;
795 }
796
797 for (int i = 1; i <= retries; i++) {
798 *bits = reset_bits; // reinit to only track last retry
799
800 // We used to do an "os::yield_all(i)" call here with the intention
801 // that yielding would increase on each retry. However, the parameter
802 // is ignored on Linux which means the yield didn't scale up. Waiting
803 // on the SR_lock below provides a much more predictable scale up for
804 // the delay. It also provides a simple/direct point to check for any
805 // safepoint requests from the VMThread
806
807 {
808 Thread* t = Thread::current();
809 MonitorLocker ml(SR_lock(),
810 t->is_Java_thread() ? Mutex::_safepoint_check_flag : Mutex::_no_safepoint_check_flag);
811 // wait with safepoint check (if we're a JavaThread - the WatcherThread
812 // can also call this) and increase delay with each retry
813 ml.wait(i * delay);
814
815 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
816 delay, bits);
817
818 // It is possible for the external suspend request to be cancelled
819 // (by a resume) before the actual suspend operation is completed.
820 // Refresh our local copy to see if we still need to wait.
821 pending = is_external_suspend();
822 }
823
824 if (!pending) {
825 // A cancelled suspend request is the only false return from
826 // is_ext_suspend_completed() that keeps us from staying in the
827 // retry loop.
828 *bits |= 0x00080000;
829 return false;
830 }
831
832 if (is_suspended) {
833 *bits |= 0x00100000;
834 return true;
835 }
836 } // end retry loop
837
838 // thread did not suspend after all our retries
839 *bits |= 0x00200000;
840 return false;
841 }
842
843 // Called from API entry points which perform stack walking. If the
844 // associated JavaThread is the current thread, then wait_for_suspend
845 // is not used. Otherwise, it determines if we should wait for the
846 // "other" thread to complete external suspension. (NOTE: in future
847 // releases the suspension mechanism should be reimplemented so this
848 // is not necessary.)
849 //
850 bool
851 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
852 if (this != JavaThread::current()) {
853 // "other" threads require special handling.
854 if (wait_for_suspend) {
855 // We are allowed to wait for the external suspend to complete
856 // so give the other thread a chance to get suspended.
857 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
858 SuspendRetryDelay, bits)) {
859 // Didn't make it so let the caller know.
860 return false;
861 }
862 }
863 // We aren't allowed to wait for the external suspend to complete
864 // so if the other thread isn't externally suspended we need to
865 // let the caller know.
866 else if (!is_ext_suspend_completed_with_lock(bits)) {
867 return false;
868 }
869 }
870
871 return true;
872 }
873
874 // GC Support
875 bool Thread::claim_par_threads_do(uintx claim_token) {
876 uintx token = _threads_do_token;
877 if (token != claim_token) {
878 uintx res = Atomic::cmpxchg(&_threads_do_token, token, claim_token);
879 if (res == token) {
880 return true;
881 }
882 guarantee(res == claim_token, "invariant");
883 }
884 return false;
885 }
886
887 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
888 if (active_handles() != NULL) {
889 active_handles()->oops_do(f);
890 }
891 // Do oop for ThreadShadow
892 f->do_oop((oop*)&_pending_exception);
893 handle_area()->oops_do(f);
894
895 // We scan thread local monitor lists here, and the remaining global
896 // monitors in ObjectSynchronizer::oops_do().
897 ObjectSynchronizer::thread_local_used_oops_do(this, f);
898 }
899
900 void Thread::metadata_handles_do(void f(Metadata*)) {
901 // Only walk the Handles in Thread.
902 if (metadata_handles() != NULL) {
903 for (int i = 0; i< metadata_handles()->length(); i++) {
904 f(metadata_handles()->at(i));
905 }
906 }
907 }
908
909 void Thread::print_on(outputStream* st, bool print_extended_info) const {
910 // get_priority assumes osthread initialized
911 if (osthread() != NULL) {
912 int os_prio;
913 if (os::get_native_priority(this, &os_prio) == OS_OK) {
914 st->print("os_prio=%d ", os_prio);
915 }
916
917 st->print("cpu=%.2fms ",
918 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
919 );
920 st->print("elapsed=%.2fs ",
921 _statistical_info.getElapsedTime() / 1000.0
922 );
923 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
924 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
925 st->print("allocated=" SIZE_FORMAT "%s ",
926 byte_size_in_proper_unit(allocated_bytes),
927 proper_unit_for_byte_size(allocated_bytes)
928 );
929 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
930 }
931
932 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
933 osthread()->print_on(st);
934 }
935 ThreadsSMRSupport::print_info_on(this, st);
936 st->print(" ");
937 debug_only(if (WizardMode) print_owned_locks_on(st);)
938 }
939
940 void Thread::print() const { print_on(tty); }
941
942 // Thread::print_on_error() is called by fatal error handler. Don't use
943 // any lock or allocate memory.
944 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
945 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
946
947 if (is_VM_thread()) { st->print("VMThread"); }
948 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
949 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
950 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
951 else { st->print("Thread"); }
952
953 if (is_Named_thread()) {
954 st->print(" \"%s\"", name());
955 }
956
957 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
958 p2i(stack_end()), p2i(stack_base()));
959
960 if (osthread()) {
961 st->print(" [id=%d]", osthread()->thread_id());
962 }
963
964 ThreadsSMRSupport::print_info_on(this, st);
965 }
966
967 void Thread::print_value_on(outputStream* st) const {
968 if (is_Named_thread()) {
969 st->print(" \"%s\" ", name());
970 }
971 st->print(INTPTR_FORMAT, p2i(this)); // print address
972 }
973
974 #ifdef ASSERT
975 void Thread::print_owned_locks_on(outputStream* st) const {
976 Mutex* cur = _owned_locks;
977 if (cur == NULL) {
978 st->print(" (no locks) ");
979 } else {
980 st->print_cr(" Locks owned:");
981 while (cur) {
982 cur->print_on(st);
983 cur = cur->next();
984 }
985 }
986 }
987
988 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
989 void Thread::check_possible_safepoint() {
990 if (!is_Java_thread()) return;
991
992 if (_no_safepoint_count > 0) {
993 print_owned_locks();
994 fatal("Possible safepoint reached by thread that does not allow it");
995 }
996 #ifdef CHECK_UNHANDLED_OOPS
997 // Clear unhandled oops in JavaThreads so we get a crash right away.
998 clear_unhandled_oops();
999 #endif // CHECK_UNHANDLED_OOPS
1000 }
1001
1002 void Thread::check_for_valid_safepoint_state() {
1003 if (!is_Java_thread()) return;
1004
1005 // Check NoSafepointVerifier, which is implied by locks taken that can be
1006 // shared with the VM thread. This makes sure that no locks with allow_vm_block
1007 // are held.
1008 check_possible_safepoint();
1009
1010 if (((JavaThread*)this)->thread_state() != _thread_in_vm) {
1011 fatal("LEAF method calling lock?");
1012 }
1013
1014 if (GCALotAtAllSafepoints) {
1015 // We could enter a safepoint here and thus have a gc
1016 InterfaceSupport::check_gc_alot();
1017 }
1018 }
1019 #endif // ASSERT
1020
1021 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1022 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1023 // used for compilation in the future. If that change is made, the need for these methods
1024 // should be revisited, and they should be removed if possible.
1025
1026 bool Thread::is_lock_owned(address adr) const {
1027 return is_in_full_stack(adr);
1028 }
1029
1030 bool Thread::set_as_starting_thread() {
1031 assert(_starting_thread == NULL, "already initialized: "
1032 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
1033 // NOTE: this must be called inside the main thread.
1034 DEBUG_ONLY(_starting_thread = this;)
1035 return os::create_main_thread((JavaThread*)this);
1036 }
1037
1038 static void initialize_class(Symbol* class_name, TRAPS) {
1039 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1040 InstanceKlass::cast(klass)->initialize(CHECK);
1041 }
1042
1043
1044 // Creates the initial ThreadGroup
1045 static Handle create_initial_thread_group(TRAPS) {
1046 Handle system_instance = JavaCalls::construct_new_instance(
1047 SystemDictionary::ThreadGroup_klass(),
1048 vmSymbols::void_method_signature(),
1049 CHECK_NH);
1050 Universe::set_system_thread_group(system_instance());
1051
1052 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1053 Handle main_instance = JavaCalls::construct_new_instance(
1054 SystemDictionary::ThreadGroup_klass(),
1055 vmSymbols::threadgroup_string_void_signature(),
1056 system_instance,
1057 string,
1058 CHECK_NH);
1059 return main_instance;
1060 }
1061
1062 // Creates the initial Thread
1063 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1064 TRAPS) {
1065 InstanceKlass* ik = SystemDictionary::Thread_klass();
1066 assert(ik->is_initialized(), "must be");
1067 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1068
1069 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1070 // constructor calls Thread.current(), which must be set here for the
1071 // initial thread.
1072 java_lang_Thread::set_thread(thread_oop(), thread);
1073 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1074 thread->set_threadObj(thread_oop());
1075
1076 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1077
1078 JavaValue result(T_VOID);
1079 JavaCalls::call_special(&result, thread_oop,
1080 ik,
1081 vmSymbols::object_initializer_name(),
1082 vmSymbols::threadgroup_string_void_signature(),
1083 thread_group,
1084 string,
1085 CHECK_NULL);
1086 return thread_oop();
1087 }
1088
1089 char java_runtime_name[128] = "";
1090 char java_runtime_version[128] = "";
1091 char java_runtime_vendor_version[128] = "";
1092 char java_runtime_vendor_vm_bug_url[128] = "";
1093
1094 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1095 static const char* get_java_runtime_name(TRAPS) {
1096 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1097 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1098 fieldDescriptor fd;
1099 bool found = k != NULL &&
1100 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1101 vmSymbols::string_signature(), &fd);
1102 if (found) {
1103 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1104 if (name_oop == NULL) {
1105 return NULL;
1106 }
1107 const char* name = java_lang_String::as_utf8_string(name_oop,
1108 java_runtime_name,
1109 sizeof(java_runtime_name));
1110 return name;
1111 } else {
1112 return NULL;
1113 }
1114 }
1115
1116 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1117 static const char* get_java_runtime_version(TRAPS) {
1118 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1119 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1120 fieldDescriptor fd;
1121 bool found = k != NULL &&
1122 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1123 vmSymbols::string_signature(), &fd);
1124 if (found) {
1125 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1126 if (name_oop == NULL) {
1127 return NULL;
1128 }
1129 const char* name = java_lang_String::as_utf8_string(name_oop,
1130 java_runtime_version,
1131 sizeof(java_runtime_version));
1132 return name;
1133 } else {
1134 return NULL;
1135 }
1136 }
1137
1138 // extract the JRE vendor version from java.lang.VersionProps.VENDOR_VERSION
1139 static const char* get_java_runtime_vendor_version(TRAPS) {
1140 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1141 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1142 fieldDescriptor fd;
1143 bool found = k != NULL &&
1144 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_vendor_version_name(),
1145 vmSymbols::string_signature(), &fd);
1146 if (found) {
1147 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1148 if (name_oop == NULL) {
1149 return NULL;
1150 }
1151 const char* name = java_lang_String::as_utf8_string(name_oop,
1152 java_runtime_vendor_version,
1153 sizeof(java_runtime_vendor_version));
1154 return name;
1155 } else {
1156 return NULL;
1157 }
1158 }
1159
1160 // extract the JRE vendor VM bug URL from java.lang.VersionProps.VENDOR_URL_VM_BUG
1161 static const char* get_java_runtime_vendor_vm_bug_url(TRAPS) {
1162 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1163 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1164 fieldDescriptor fd;
1165 bool found = k != NULL &&
1166 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_vendor_vm_bug_url_name(),
1167 vmSymbols::string_signature(), &fd);
1168 if (found) {
1169 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1170 if (name_oop == NULL) {
1171 return NULL;
1172 }
1173 const char* name = java_lang_String::as_utf8_string(name_oop,
1174 java_runtime_vendor_vm_bug_url,
1175 sizeof(java_runtime_vendor_vm_bug_url));
1176 return name;
1177 } else {
1178 return NULL;
1179 }
1180 }
1181
1182 // General purpose hook into Java code, run once when the VM is initialized.
1183 // The Java library method itself may be changed independently from the VM.
1184 static void call_postVMInitHook(TRAPS) {
1185 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1186 if (klass != NULL) {
1187 JavaValue result(T_VOID);
1188 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1189 vmSymbols::void_method_signature(),
1190 CHECK);
1191 }
1192 }
1193
1194 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1195 bool daemon, TRAPS) {
1196 assert(thread_group.not_null(), "thread group should be specified");
1197 assert(threadObj() == NULL, "should only create Java thread object once");
1198
1199 InstanceKlass* ik = SystemDictionary::Thread_klass();
1200 assert(ik->is_initialized(), "must be");
1201 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1202
1203 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1204 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1205 // constructor calls Thread.current(), which must be set here.
1206 java_lang_Thread::set_thread(thread_oop(), this);
1207 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1208 set_threadObj(thread_oop());
1209
1210 JavaValue result(T_VOID);
1211 if (thread_name != NULL) {
1212 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1213 // Thread gets assigned specified name and null target
1214 JavaCalls::call_special(&result,
1215 thread_oop,
1216 ik,
1217 vmSymbols::object_initializer_name(),
1218 vmSymbols::threadgroup_string_void_signature(),
1219 thread_group,
1220 name,
1221 THREAD);
1222 } else {
1223 // Thread gets assigned name "Thread-nnn" and null target
1224 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1225 JavaCalls::call_special(&result,
1226 thread_oop,
1227 ik,
1228 vmSymbols::object_initializer_name(),
1229 vmSymbols::threadgroup_runnable_void_signature(),
1230 thread_group,
1231 Handle(),
1232 THREAD);
1233 }
1234
1235
1236 if (daemon) {
1237 java_lang_Thread::set_daemon(thread_oop());
1238 }
1239
1240 if (HAS_PENDING_EXCEPTION) {
1241 return;
1242 }
1243
1244 Klass* group = SystemDictionary::ThreadGroup_klass();
1245 Handle threadObj(THREAD, this->threadObj());
1246
1247 JavaCalls::call_special(&result,
1248 thread_group,
1249 group,
1250 vmSymbols::add_method_name(),
1251 vmSymbols::thread_void_signature(),
1252 threadObj, // Arg 1
1253 THREAD);
1254 }
1255
1256 // List of all NonJavaThreads and safe iteration over that list.
1257
1258 class NonJavaThread::List {
1259 public:
1260 NonJavaThread* volatile _head;
1261 SingleWriterSynchronizer _protect;
1262
1263 List() : _head(NULL), _protect() {}
1264 };
1265
1266 NonJavaThread::List NonJavaThread::_the_list;
1267
1268 NonJavaThread::Iterator::Iterator() :
1269 _protect_enter(_the_list._protect.enter()),
1270 _current(Atomic::load_acquire(&_the_list._head))
1271 {}
1272
1273 NonJavaThread::Iterator::~Iterator() {
1274 _the_list._protect.exit(_protect_enter);
1275 }
1276
1277 void NonJavaThread::Iterator::step() {
1278 assert(!end(), "precondition");
1279 _current = Atomic::load_acquire(&_current->_next);
1280 }
1281
1282 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) {
1283 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!");
1284 }
1285
1286 NonJavaThread::~NonJavaThread() { }
1287
1288 void NonJavaThread::add_to_the_list() {
1289 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1290 // Initialize BarrierSet-related data before adding to list.
1291 BarrierSet::barrier_set()->on_thread_attach(this);
1292 Atomic::release_store(&_next, _the_list._head);
1293 Atomic::release_store(&_the_list._head, this);
1294 }
1295
1296 void NonJavaThread::remove_from_the_list() {
1297 {
1298 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1299 // Cleanup BarrierSet-related data before removing from list.
1300 BarrierSet::barrier_set()->on_thread_detach(this);
1301 NonJavaThread* volatile* p = &_the_list._head;
1302 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) {
1303 if (t == this) {
1304 *p = _next;
1305 break;
1306 }
1307 }
1308 }
1309 // Wait for any in-progress iterators. Concurrent synchronize is not
1310 // allowed, so do it while holding a dedicated lock. Outside and distinct
1311 // from NJTList_lock in case an iteration attempts to lock it.
1312 MutexLocker ml(NonJavaThreadsListSync_lock, Mutex::_no_safepoint_check_flag);
1313 _the_list._protect.synchronize();
1314 _next = NULL; // Safe to drop the link now.
1315 }
1316
1317 void NonJavaThread::pre_run() {
1318 add_to_the_list();
1319
1320 // This is slightly odd in that NamedThread is a subclass, but
1321 // in fact name() is defined in Thread
1322 assert(this->name() != NULL, "thread name was not set before it was started");
1323 this->set_native_thread_name(this->name());
1324 }
1325
1326 void NonJavaThread::post_run() {
1327 JFR_ONLY(Jfr::on_thread_exit(this);)
1328 remove_from_the_list();
1329 // Ensure thread-local-storage is cleared before termination.
1330 Thread::clear_thread_current();
1331 }
1332
1333 // NamedThread -- non-JavaThread subclasses with multiple
1334 // uniquely named instances should derive from this.
1335 NamedThread::NamedThread() :
1336 NonJavaThread(),
1337 _name(NULL),
1338 _processed_thread(NULL),
1339 _gc_id(GCId::undefined())
1340 {}
1341
1342 NamedThread::~NamedThread() {
1343 FREE_C_HEAP_ARRAY(char, _name);
1344 }
1345
1346 void NamedThread::set_name(const char* format, ...) {
1347 guarantee(_name == NULL, "Only get to set name once.");
1348 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1349 va_list ap;
1350 va_start(ap, format);
1351 jio_vsnprintf(_name, max_name_len, format, ap);
1352 va_end(ap);
1353 }
1354
1355 void NamedThread::print_on(outputStream* st) const {
1356 st->print("\"%s\" ", name());
1357 Thread::print_on(st);
1358 st->cr();
1359 }
1360
1361
1362 // ======= WatcherThread ========
1363
1364 // The watcher thread exists to simulate timer interrupts. It should
1365 // be replaced by an abstraction over whatever native support for
1366 // timer interrupts exists on the platform.
1367
1368 WatcherThread* WatcherThread::_watcher_thread = NULL;
1369 bool WatcherThread::_startable = false;
1370 volatile bool WatcherThread::_should_terminate = false;
1371
1372 WatcherThread::WatcherThread() : NonJavaThread() {
1373 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1374 if (os::create_thread(this, os::watcher_thread)) {
1375 _watcher_thread = this;
1376
1377 // Set the watcher thread to the highest OS priority which should not be
1378 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1379 // is created. The only normal thread using this priority is the reference
1380 // handler thread, which runs for very short intervals only.
1381 // If the VMThread's priority is not lower than the WatcherThread profiling
1382 // will be inaccurate.
1383 os::set_priority(this, MaxPriority);
1384 if (!DisableStartThread) {
1385 os::start_thread(this);
1386 }
1387 }
1388 }
1389
1390 int WatcherThread::sleep() const {
1391 // The WatcherThread does not participate in the safepoint protocol
1392 // for the PeriodicTask_lock because it is not a JavaThread.
1393 MonitorLocker ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1394
1395 if (_should_terminate) {
1396 // check for termination before we do any housekeeping or wait
1397 return 0; // we did not sleep.
1398 }
1399
1400 // remaining will be zero if there are no tasks,
1401 // causing the WatcherThread to sleep until a task is
1402 // enrolled
1403 int remaining = PeriodicTask::time_to_wait();
1404 int time_slept = 0;
1405
1406 // we expect this to timeout - we only ever get unparked when
1407 // we should terminate or when a new task has been enrolled
1408 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1409
1410 jlong time_before_loop = os::javaTimeNanos();
1411
1412 while (true) {
1413 bool timedout = ml.wait(remaining);
1414 jlong now = os::javaTimeNanos();
1415
1416 if (remaining == 0) {
1417 // if we didn't have any tasks we could have waited for a long time
1418 // consider the time_slept zero and reset time_before_loop
1419 time_slept = 0;
1420 time_before_loop = now;
1421 } else {
1422 // need to recalculate since we might have new tasks in _tasks
1423 time_slept = (int) ((now - time_before_loop) / 1000000);
1424 }
1425
1426 // Change to task list or spurious wakeup of some kind
1427 if (timedout || _should_terminate) {
1428 break;
1429 }
1430
1431 remaining = PeriodicTask::time_to_wait();
1432 if (remaining == 0) {
1433 // Last task was just disenrolled so loop around and wait until
1434 // another task gets enrolled
1435 continue;
1436 }
1437
1438 remaining -= time_slept;
1439 if (remaining <= 0) {
1440 break;
1441 }
1442 }
1443
1444 return time_slept;
1445 }
1446
1447 void WatcherThread::run() {
1448 assert(this == watcher_thread(), "just checking");
1449
1450 this->set_active_handles(JNIHandleBlock::allocate_block());
1451 while (true) {
1452 assert(watcher_thread() == Thread::current(), "thread consistency check");
1453 assert(watcher_thread() == this, "thread consistency check");
1454
1455 // Calculate how long it'll be until the next PeriodicTask work
1456 // should be done, and sleep that amount of time.
1457 int time_waited = sleep();
1458
1459 if (VMError::is_error_reported()) {
1460 // A fatal error has happened, the error handler(VMError::report_and_die)
1461 // should abort JVM after creating an error log file. However in some
1462 // rare cases, the error handler itself might deadlock. Here periodically
1463 // check for error reporting timeouts, and if it happens, just proceed to
1464 // abort the VM.
1465
1466 // This code is in WatcherThread because WatcherThread wakes up
1467 // periodically so the fatal error handler doesn't need to do anything;
1468 // also because the WatcherThread is less likely to crash than other
1469 // threads.
1470
1471 for (;;) {
1472 // Note: we use naked sleep in this loop because we want to avoid using
1473 // any kind of VM infrastructure which may be broken at this point.
1474 if (VMError::check_timeout()) {
1475 // We hit error reporting timeout. Error reporting was interrupted and
1476 // will be wrapping things up now (closing files etc). Give it some more
1477 // time, then quit the VM.
1478 os::naked_short_sleep(200);
1479 // Print a message to stderr.
1480 fdStream err(defaultStream::output_fd());
1481 err.print_raw_cr("# [ timer expired, abort... ]");
1482 // skip atexit/vm_exit/vm_abort hooks
1483 os::die();
1484 }
1485
1486 // Wait a second, then recheck for timeout.
1487 os::naked_short_sleep(999);
1488 }
1489 }
1490
1491 if (_should_terminate) {
1492 // check for termination before posting the next tick
1493 break;
1494 }
1495
1496 PeriodicTask::real_time_tick(time_waited);
1497 }
1498
1499 // Signal that it is terminated
1500 {
1501 MutexLocker mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1502 _watcher_thread = NULL;
1503 Terminator_lock->notify_all();
1504 }
1505 }
1506
1507 void WatcherThread::start() {
1508 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1509
1510 if (watcher_thread() == NULL && _startable) {
1511 _should_terminate = false;
1512 // Create the single instance of WatcherThread
1513 new WatcherThread();
1514 }
1515 }
1516
1517 void WatcherThread::make_startable() {
1518 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1519 _startable = true;
1520 }
1521
1522 void WatcherThread::stop() {
1523 {
1524 // Follow normal safepoint aware lock enter protocol since the
1525 // WatcherThread is stopped by another JavaThread.
1526 MutexLocker ml(PeriodicTask_lock);
1527 _should_terminate = true;
1528
1529 WatcherThread* watcher = watcher_thread();
1530 if (watcher != NULL) {
1531 // unpark the WatcherThread so it can see that it should terminate
1532 watcher->unpark();
1533 }
1534 }
1535
1536 MonitorLocker mu(Terminator_lock);
1537
1538 while (watcher_thread() != NULL) {
1539 // This wait should make safepoint checks, wait without a timeout,
1540 // and wait as a suspend-equivalent condition.
1541 mu.wait(0, Mutex::_as_suspend_equivalent_flag);
1542 }
1543 }
1544
1545 void WatcherThread::unpark() {
1546 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1547 PeriodicTask_lock->notify();
1548 }
1549
1550 void WatcherThread::print_on(outputStream* st) const {
1551 st->print("\"%s\" ", name());
1552 Thread::print_on(st);
1553 st->cr();
1554 }
1555
1556 // ======= JavaThread ========
1557
1558 #if INCLUDE_JVMCI
1559
1560 jlong* JavaThread::_jvmci_old_thread_counters;
1561
1562 bool jvmci_counters_include(JavaThread* thread) {
1563 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1564 }
1565
1566 void JavaThread::collect_counters(jlong* array, int length) {
1567 assert(length == JVMCICounterSize, "wrong value");
1568 for (int i = 0; i < length; i++) {
1569 array[i] = _jvmci_old_thread_counters[i];
1570 }
1571 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
1572 if (jvmci_counters_include(tp)) {
1573 for (int i = 0; i < length; i++) {
1574 array[i] += tp->_jvmci_counters[i];
1575 }
1576 }
1577 }
1578 }
1579
1580 // Attempt to enlarge the array for per thread counters.
1581 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
1582 jlong* new_counters = NEW_C_HEAP_ARRAY(jlong, new_size, mtJVMCI);
1583 if (old_counters == NULL) {
1584 old_counters = new_counters;
1585 memset(old_counters, 0, sizeof(jlong) * new_size);
1586 } else {
1587 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
1588 new_counters[i] = old_counters[i];
1589 }
1590 if (new_size > current_size) {
1591 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
1592 }
1593 FREE_C_HEAP_ARRAY(jlong, old_counters);
1594 }
1595 return new_counters;
1596 }
1597
1598 // Attempt to enlarge the array for per thread counters.
1599 void JavaThread::resize_counters(int current_size, int new_size) {
1600 _jvmci_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
1601 }
1602
1603 class VM_JVMCIResizeCounters : public VM_Operation {
1604 private:
1605 int _new_size;
1606
1607 public:
1608 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size) { }
1609 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
1610 bool allow_nested_vm_operations() const { return true; }
1611 void doit() {
1612 // Resize the old thread counters array
1613 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
1614 JavaThread::_jvmci_old_thread_counters = new_counters;
1615
1616 // Now resize each threads array
1617 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
1618 tp->resize_counters(JVMCICounterSize, _new_size);
1619 }
1620 JVMCICounterSize = _new_size;
1621 }
1622 };
1623
1624 void JavaThread::resize_all_jvmci_counters(int new_size) {
1625 VM_JVMCIResizeCounters op(new_size);
1626 VMThread::execute(&op);
1627 }
1628
1629 #endif // INCLUDE_JVMCI
1630
1631 // A JavaThread is a normal Java thread
1632
1633 void JavaThread::initialize() {
1634 // Initialize fields
1635
1636 set_saved_exception_pc(NULL);
1637 set_threadObj(NULL);
1638 _anchor.clear();
1639 set_entry_point(NULL);
1640 set_jni_functions(jni_functions());
1641 set_callee_target(NULL);
1642 set_vm_result(NULL);
1643 set_vm_result_2(NULL);
1644 set_vframe_array_head(NULL);
1645 set_vframe_array_last(NULL);
1646 set_deferred_locals(NULL);
1647 set_deopt_mark(NULL);
1648 set_deopt_compiled_method(NULL);
1649 set_monitor_chunks(NULL);
1650 _on_thread_list = false;
1651 _thread_state = _thread_new;
1652 _terminated = _not_terminated;
1653 _array_for_gc = NULL;
1654 _suspend_equivalent = false;
1655 _in_deopt_handler = 0;
1656 _doing_unsafe_access = false;
1657 _stack_guard_state = stack_guard_unused;
1658 #if INCLUDE_JVMCI
1659 _pending_monitorenter = false;
1660 _pending_deoptimization = -1;
1661 _pending_failed_speculation = 0;
1662 _pending_transfer_to_interpreter = false;
1663 _in_retryable_allocation = false;
1664 _jvmci._alternate_call_target = NULL;
1665 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1666 _jvmci_counters = NULL;
1667 if (JVMCICounterSize > 0) {
1668 resize_counters(0, (int) JVMCICounterSize);
1669 }
1670 #endif // INCLUDE_JVMCI
1671 _reserved_stack_activation = NULL; // stack base not known yet
1672 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1673 _exception_pc = 0;
1674 _exception_handler_pc = 0;
1675 _is_method_handle_return = 0;
1676 _jvmti_thread_state= NULL;
1677 _should_post_on_exceptions_flag = JNI_FALSE;
1678 _interp_only_mode = 0;
1679 _special_runtime_exit_condition = _no_async_condition;
1680 _pending_async_exception = NULL;
1681 _thread_stat = NULL;
1682 _thread_stat = new ThreadStatistics();
1683 _jni_active_critical = 0;
1684 _pending_jni_exception_check_fn = NULL;
1685 _do_not_unlock_if_synchronized = false;
1686 _cached_monitor_info = NULL;
1687 _parker = Parker::Allocate(this);
1688 _SleepEvent = ParkEvent::Allocate(this);
1689 // Setup safepoint state info for this thread
1690 ThreadSafepointState::create(this);
1691
1692 debug_only(_java_call_counter = 0);
1693
1694 // JVMTI PopFrame support
1695 _popframe_condition = popframe_inactive;
1696 _popframe_preserved_args = NULL;
1697 _popframe_preserved_args_size = 0;
1698 _frames_to_pop_failed_realloc = 0;
1699
1700 SafepointMechanism::initialize_header(this);
1701
1702 _class_to_be_initialized = NULL;
1703
1704 pd_initialize();
1705 }
1706
1707 JavaThread::JavaThread(bool is_attaching_via_jni) :
1708 Thread() {
1709 initialize();
1710 if (is_attaching_via_jni) {
1711 _jni_attach_state = _attaching_via_jni;
1712 } else {
1713 _jni_attach_state = _not_attaching_via_jni;
1714 }
1715 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1716 }
1717
1718
1719 // interrupt support
1720
1721 void JavaThread::interrupt() {
1722 debug_only(check_for_dangling_thread_pointer(this);)
1723
1724 // For Windows _interrupt_event
1725 osthread()->set_interrupted(true);
1726
1727 // For Thread.sleep
1728 _SleepEvent->unpark();
1729
1730 // For JSR166 LockSupport.park
1731 parker()->unpark();
1732
1733 // For ObjectMonitor and JvmtiRawMonitor
1734 _ParkEvent->unpark();
1735 }
1736
1737
1738 bool JavaThread::is_interrupted(bool clear_interrupted) {
1739 debug_only(check_for_dangling_thread_pointer(this);)
1740
1741 if (threadObj() == NULL) {
1742 // If there is no j.l.Thread then it is impossible to have
1743 // been interrupted. We can find NULL during VM initialization
1744 // or when a JNI thread is still in the process of attaching.
1745 // In such cases this must be the current thread.
1746 assert(this == Thread::current(), "invariant");
1747 return false;
1748 }
1749
1750 bool interrupted = java_lang_Thread::interrupted(threadObj());
1751
1752 // NOTE that since there is no "lock" around the interrupt and
1753 // is_interrupted operations, there is the possibility that the
1754 // interrupted flag will be "false" but that the
1755 // low-level events will be in the signaled state. This is
1756 // intentional. The effect of this is that Object.wait() and
1757 // LockSupport.park() will appear to have a spurious wakeup, which
1758 // is allowed and not harmful, and the possibility is so rare that
1759 // it is not worth the added complexity to add yet another lock.
1760 // For the sleep event an explicit reset is performed on entry
1761 // to JavaThread::sleep, so there is no early return. It has also been
1762 // recommended not to put the interrupted flag into the "event"
1763 // structure because it hides the issue.
1764 // Also, because there is no lock, we must only clear the interrupt
1765 // state if we are going to report that we were interrupted; otherwise
1766 // an interrupt that happens just after we read the field would be lost.
1767 if (interrupted && clear_interrupted) {
1768 assert(this == Thread::current(), "only the current thread can clear");
1769 java_lang_Thread::set_interrupted(threadObj(), false);
1770 osthread()->set_interrupted(false);
1771 }
1772
1773 return interrupted;
1774 }
1775
1776 bool JavaThread::reguard_stack(address cur_sp) {
1777 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1778 && _stack_guard_state != stack_guard_reserved_disabled) {
1779 return true; // Stack already guarded or guard pages not needed.
1780 }
1781
1782 if (register_stack_overflow()) {
1783 // For those architectures which have separate register and
1784 // memory stacks, we must check the register stack to see if
1785 // it has overflowed.
1786 return false;
1787 }
1788
1789 // Java code never executes within the yellow zone: the latter is only
1790 // there to provoke an exception during stack banging. If java code
1791 // is executing there, either StackShadowPages should be larger, or
1792 // some exception code in c1, c2 or the interpreter isn't unwinding
1793 // when it should.
1794 guarantee(cur_sp > stack_reserved_zone_base(),
1795 "not enough space to reguard - increase StackShadowPages");
1796 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1797 enable_stack_yellow_reserved_zone();
1798 if (reserved_stack_activation() != stack_base()) {
1799 set_reserved_stack_activation(stack_base());
1800 }
1801 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1802 set_reserved_stack_activation(stack_base());
1803 enable_stack_reserved_zone();
1804 }
1805 return true;
1806 }
1807
1808 bool JavaThread::reguard_stack(void) {
1809 return reguard_stack(os::current_stack_pointer());
1810 }
1811
1812 void JavaThread::block_if_vm_exited() {
1813 if (_terminated == _vm_exited) {
1814 // _vm_exited is set at safepoint, and Threads_lock is never released
1815 // we will block here forever.
1816 // Here we can be doing a jump from a safe state to an unsafe state without
1817 // proper transition, but it happens after the final safepoint has begun.
1818 set_thread_state(_thread_in_vm);
1819 Threads_lock->lock();
1820 ShouldNotReachHere();
1821 }
1822 }
1823
1824
1825 // Remove this ifdef when C1 is ported to the compiler interface.
1826 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1827 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1828
1829 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1830 Thread() {
1831 initialize();
1832 _jni_attach_state = _not_attaching_via_jni;
1833 set_entry_point(entry_point);
1834 // Create the native thread itself.
1835 // %note runtime_23
1836 os::ThreadType thr_type = os::java_thread;
1837 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1838 os::java_thread;
1839 os::create_thread(this, thr_type, stack_sz);
1840 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1841 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1842 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1843 // the exception consists of creating the exception object & initializing it, initialization
1844 // will leave the VM via a JavaCall and then all locks must be unlocked).
1845 //
1846 // The thread is still suspended when we reach here. Thread must be explicit started
1847 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1848 // by calling Threads:add. The reason why this is not done here, is because the thread
1849 // object must be fully initialized (take a look at JVM_Start)
1850 }
1851
1852 JavaThread::~JavaThread() {
1853
1854 // JSR166 -- return the parker to the free list
1855 Parker::Release(_parker);
1856 _parker = NULL;
1857
1858 // Return the sleep event to the free list
1859 ParkEvent::Release(_SleepEvent);
1860 _SleepEvent = NULL;
1861
1862 // Free any remaining previous UnrollBlock
1863 vframeArray* old_array = vframe_array_last();
1864
1865 if (old_array != NULL) {
1866 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1867 old_array->set_unroll_block(NULL);
1868 delete old_info;
1869 delete old_array;
1870 }
1871
1872 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1873 if (deferred != NULL) {
1874 // This can only happen if thread is destroyed before deoptimization occurs.
1875 assert(deferred->length() != 0, "empty array!");
1876 do {
1877 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1878 deferred->remove_at(0);
1879 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1880 delete dlv;
1881 } while (deferred->length() != 0);
1882 delete deferred;
1883 }
1884
1885 // All Java related clean up happens in exit
1886 ThreadSafepointState::destroy(this);
1887 if (_thread_stat != NULL) delete _thread_stat;
1888
1889 #if INCLUDE_JVMCI
1890 if (JVMCICounterSize > 0) {
1891 if (jvmci_counters_include(this)) {
1892 for (int i = 0; i < JVMCICounterSize; i++) {
1893 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1894 }
1895 }
1896 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1897 }
1898 #endif // INCLUDE_JVMCI
1899 }
1900
1901
1902 // First JavaThread specific code executed by a new Java thread.
1903 void JavaThread::pre_run() {
1904 // empty - see comments in run()
1905 }
1906
1907 // The main routine called by a new Java thread. This isn't overridden
1908 // by subclasses, instead different subclasses define a different "entry_point"
1909 // which defines the actual logic for that kind of thread.
1910 void JavaThread::run() {
1911 // initialize thread-local alloc buffer related fields
1912 this->initialize_tlab();
1913
1914 // Used to test validity of stack trace backs.
1915 // This can't be moved into pre_run() else we invalidate
1916 // the requirement that thread_main_inner is lower on
1917 // the stack. Consequently all the initialization logic
1918 // stays here in run() rather than pre_run().
1919 this->record_base_of_stack_pointer();
1920
1921 this->create_stack_guard_pages();
1922
1923 this->cache_global_variables();
1924
1925 // Thread is now sufficiently initialized to be handled by the safepoint code as being
1926 // in the VM. Change thread state from _thread_new to _thread_in_vm
1927 ThreadStateTransition::transition(this, _thread_new, _thread_in_vm);
1928 // Before a thread is on the threads list it is always safe, so after leaving the
1929 // _thread_new we should emit a instruction barrier. The distance to modified code
1930 // from here is probably far enough, but this is consistent and safe.
1931 OrderAccess::cross_modify_fence();
1932
1933 assert(JavaThread::current() == this, "sanity check");
1934 assert(!Thread::current()->owns_locks(), "sanity check");
1935
1936 DTRACE_THREAD_PROBE(start, this);
1937
1938 // This operation might block. We call that after all safepoint checks for a new thread has
1939 // been completed.
1940 this->set_active_handles(JNIHandleBlock::allocate_block());
1941
1942 if (JvmtiExport::should_post_thread_life()) {
1943 JvmtiExport::post_thread_start(this);
1944
1945 }
1946
1947 // We call another function to do the rest so we are sure that the stack addresses used
1948 // from there will be lower than the stack base just computed.
1949 thread_main_inner();
1950 }
1951
1952 void JavaThread::thread_main_inner() {
1953 assert(JavaThread::current() == this, "sanity check");
1954 assert(this->threadObj() != NULL, "just checking");
1955
1956 // Execute thread entry point unless this thread has a pending exception
1957 // or has been stopped before starting.
1958 // Note: Due to JVM_StopThread we can have pending exceptions already!
1959 if (!this->has_pending_exception() &&
1960 !java_lang_Thread::is_stillborn(this->threadObj())) {
1961 {
1962 ResourceMark rm(this);
1963 this->set_native_thread_name(this->get_thread_name());
1964 }
1965 HandleMark hm(this);
1966 this->entry_point()(this, this);
1967 }
1968
1969 DTRACE_THREAD_PROBE(stop, this);
1970
1971 // Cleanup is handled in post_run()
1972 }
1973
1974 // Shared teardown for all JavaThreads
1975 void JavaThread::post_run() {
1976 this->exit(false);
1977 // Defer deletion to here to ensure 'this' is still referenceable in call_run
1978 // for any shared tear-down.
1979 this->smr_delete();
1980 }
1981
1982 static void ensure_join(JavaThread* thread) {
1983 // We do not need to grab the Threads_lock, since we are operating on ourself.
1984 Handle threadObj(thread, thread->threadObj());
1985 assert(threadObj.not_null(), "java thread object must exist");
1986 ObjectLocker lock(threadObj, thread);
1987 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1988 thread->clear_pending_exception();
1989 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1990 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1991 // Clear the native thread instance - this makes isAlive return false and allows the join()
1992 // to complete once we've done the notify_all below
1993 java_lang_Thread::set_thread(threadObj(), NULL);
1994 lock.notify_all(thread);
1995 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1996 thread->clear_pending_exception();
1997 }
1998
1999 static bool is_daemon(oop threadObj) {
2000 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
2001 }
2002
2003 // For any new cleanup additions, please check to see if they need to be applied to
2004 // cleanup_failed_attach_current_thread as well.
2005 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
2006 assert(this == JavaThread::current(), "thread consistency check");
2007
2008 elapsedTimer _timer_exit_phase1;
2009 elapsedTimer _timer_exit_phase2;
2010 elapsedTimer _timer_exit_phase3;
2011 elapsedTimer _timer_exit_phase4;
2012
2013 if (log_is_enabled(Debug, os, thread, timer)) {
2014 _timer_exit_phase1.start();
2015 }
2016
2017 HandleMark hm(this);
2018 Handle uncaught_exception(this, this->pending_exception());
2019 this->clear_pending_exception();
2020 Handle threadObj(this, this->threadObj());
2021 assert(threadObj.not_null(), "Java thread object should be created");
2022
2023 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
2024 {
2025 EXCEPTION_MARK;
2026
2027 CLEAR_PENDING_EXCEPTION;
2028 }
2029 if (!destroy_vm) {
2030 if (uncaught_exception.not_null()) {
2031 EXCEPTION_MARK;
2032 // Call method Thread.dispatchUncaughtException().
2033 Klass* thread_klass = SystemDictionary::Thread_klass();
2034 JavaValue result(T_VOID);
2035 JavaCalls::call_virtual(&result,
2036 threadObj, thread_klass,
2037 vmSymbols::dispatchUncaughtException_name(),
2038 vmSymbols::throwable_void_signature(),
2039 uncaught_exception,
2040 THREAD);
2041 if (HAS_PENDING_EXCEPTION) {
2042 ResourceMark rm(this);
2043 jio_fprintf(defaultStream::error_stream(),
2044 "\nException: %s thrown from the UncaughtExceptionHandler"
2045 " in thread \"%s\"\n",
2046 pending_exception()->klass()->external_name(),
2047 get_thread_name());
2048 CLEAR_PENDING_EXCEPTION;
2049 }
2050 }
2051 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
2052
2053 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
2054 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
2055 // is deprecated anyhow.
2056 if (!is_Compiler_thread()) {
2057 int count = 3;
2058 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
2059 EXCEPTION_MARK;
2060 JavaValue result(T_VOID);
2061 Klass* thread_klass = SystemDictionary::Thread_klass();
2062 JavaCalls::call_virtual(&result,
2063 threadObj, thread_klass,
2064 vmSymbols::exit_method_name(),
2065 vmSymbols::void_method_signature(),
2066 THREAD);
2067 CLEAR_PENDING_EXCEPTION;
2068 }
2069 }
2070 // notify JVMTI
2071 if (JvmtiExport::should_post_thread_life()) {
2072 JvmtiExport::post_thread_end(this);
2073 }
2074
2075 // We have notified the agents that we are exiting, before we go on,
2076 // we must check for a pending external suspend request and honor it
2077 // in order to not surprise the thread that made the suspend request.
2078 while (true) {
2079 {
2080 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2081 if (!is_external_suspend()) {
2082 set_terminated(_thread_exiting);
2083 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
2084 break;
2085 }
2086 // Implied else:
2087 // Things get a little tricky here. We have a pending external
2088 // suspend request, but we are holding the SR_lock so we
2089 // can't just self-suspend. So we temporarily drop the lock
2090 // and then self-suspend.
2091 }
2092
2093 ThreadBlockInVM tbivm(this);
2094 java_suspend_self();
2095
2096 // We're done with this suspend request, but we have to loop around
2097 // and check again. Eventually we will get SR_lock without a pending
2098 // external suspend request and will be able to mark ourselves as
2099 // exiting.
2100 }
2101 // no more external suspends are allowed at this point
2102 } else {
2103 assert(!is_terminated() && !is_exiting(), "must not be exiting");
2104 // before_exit() has already posted JVMTI THREAD_END events
2105 }
2106
2107 if (log_is_enabled(Debug, os, thread, timer)) {
2108 _timer_exit_phase1.stop();
2109 _timer_exit_phase2.start();
2110 }
2111
2112 // Capture daemon status before the thread is marked as terminated.
2113 bool daemon = is_daemon(threadObj());
2114
2115 // Notify waiters on thread object. This has to be done after exit() is called
2116 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
2117 // group should have the destroyed bit set before waiters are notified).
2118 ensure_join(this);
2119 assert(!this->has_pending_exception(), "ensure_join should have cleared");
2120
2121 if (log_is_enabled(Debug, os, thread, timer)) {
2122 _timer_exit_phase2.stop();
2123 _timer_exit_phase3.start();
2124 }
2125 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
2126 // held by this thread must be released. The spec does not distinguish
2127 // between JNI-acquired and regular Java monitors. We can only see
2128 // regular Java monitors here if monitor enter-exit matching is broken.
2129 //
2130 // ensure_join() ignores IllegalThreadStateExceptions, and so does
2131 // ObjectSynchronizer::release_monitors_owned_by_thread().
2132 if (exit_type == jni_detach) {
2133 // Sanity check even though JNI DetachCurrentThread() would have
2134 // returned JNI_ERR if there was a Java frame. JavaThread exit
2135 // should be done executing Java code by the time we get here.
2136 assert(!this->has_last_Java_frame(),
2137 "should not have a Java frame when detaching or exiting");
2138 ObjectSynchronizer::release_monitors_owned_by_thread(this);
2139 assert(!this->has_pending_exception(), "release_monitors should have cleared");
2140 }
2141
2142 // These things needs to be done while we are still a Java Thread. Make sure that thread
2143 // is in a consistent state, in case GC happens
2144 JFR_ONLY(Jfr::on_thread_exit(this);)
2145
2146 if (active_handles() != NULL) {
2147 JNIHandleBlock* block = active_handles();
2148 set_active_handles(NULL);
2149 JNIHandleBlock::release_block(block);
2150 }
2151
2152 if (free_handle_block() != NULL) {
2153 JNIHandleBlock* block = free_handle_block();
2154 set_free_handle_block(NULL);
2155 JNIHandleBlock::release_block(block);
2156 }
2157
2158 // These have to be removed while this is still a valid thread.
2159 remove_stack_guard_pages();
2160
2161 if (UseTLAB) {
2162 tlab().retire();
2163 }
2164
2165 if (JvmtiEnv::environments_might_exist()) {
2166 JvmtiExport::cleanup_thread(this);
2167 }
2168
2169 // We must flush any deferred card marks and other various GC barrier
2170 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2171 // before removing a thread from the list of active threads.
2172 BarrierSet::barrier_set()->on_thread_detach(this);
2173
2174 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2175 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2176 os::current_thread_id());
2177
2178 if (log_is_enabled(Debug, os, thread, timer)) {
2179 _timer_exit_phase3.stop();
2180 _timer_exit_phase4.start();
2181 }
2182 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2183 Threads::remove(this, daemon);
2184
2185 if (log_is_enabled(Debug, os, thread, timer)) {
2186 _timer_exit_phase4.stop();
2187 ResourceMark rm(this);
2188 log_debug(os, thread, timer)("name='%s'"
2189 ", exit-phase1=" JLONG_FORMAT
2190 ", exit-phase2=" JLONG_FORMAT
2191 ", exit-phase3=" JLONG_FORMAT
2192 ", exit-phase4=" JLONG_FORMAT,
2193 get_thread_name(),
2194 _timer_exit_phase1.milliseconds(),
2195 _timer_exit_phase2.milliseconds(),
2196 _timer_exit_phase3.milliseconds(),
2197 _timer_exit_phase4.milliseconds());
2198 }
2199 }
2200
2201 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
2202 if (active_handles() != NULL) {
2203 JNIHandleBlock* block = active_handles();
2204 set_active_handles(NULL);
2205 JNIHandleBlock::release_block(block);
2206 }
2207
2208 if (free_handle_block() != NULL) {
2209 JNIHandleBlock* block = free_handle_block();
2210 set_free_handle_block(NULL);
2211 JNIHandleBlock::release_block(block);
2212 }
2213
2214 // These have to be removed while this is still a valid thread.
2215 remove_stack_guard_pages();
2216
2217 if (UseTLAB) {
2218 tlab().retire();
2219 }
2220
2221 BarrierSet::barrier_set()->on_thread_detach(this);
2222
2223 Threads::remove(this, is_daemon);
2224 this->smr_delete();
2225 }
2226
2227 JavaThread* JavaThread::active() {
2228 Thread* thread = Thread::current();
2229 if (thread->is_Java_thread()) {
2230 return (JavaThread*) thread;
2231 } else {
2232 assert(thread->is_VM_thread(), "this must be a vm thread");
2233 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2234 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2235 assert(ret->is_Java_thread(), "must be a Java thread");
2236 return ret;
2237 }
2238 }
2239
2240 bool JavaThread::is_lock_owned(address adr) const {
2241 if (Thread::is_lock_owned(adr)) return true;
2242
2243 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2244 if (chunk->contains(adr)) return true;
2245 }
2246
2247 return false;
2248 }
2249
2250
2251 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2252 chunk->set_next(monitor_chunks());
2253 set_monitor_chunks(chunk);
2254 }
2255
2256 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2257 guarantee(monitor_chunks() != NULL, "must be non empty");
2258 if (monitor_chunks() == chunk) {
2259 set_monitor_chunks(chunk->next());
2260 } else {
2261 MonitorChunk* prev = monitor_chunks();
2262 while (prev->next() != chunk) prev = prev->next();
2263 prev->set_next(chunk->next());
2264 }
2265 }
2266
2267 // JVM support.
2268
2269 // Note: this function shouldn't block if it's called in
2270 // _thread_in_native_trans state (such as from
2271 // check_special_condition_for_native_trans()).
2272 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2273
2274 if (has_last_Java_frame() && has_async_condition()) {
2275 // If we are at a polling page safepoint (not a poll return)
2276 // then we must defer async exception because live registers
2277 // will be clobbered by the exception path. Poll return is
2278 // ok because the call we a returning from already collides
2279 // with exception handling registers and so there is no issue.
2280 // (The exception handling path kills call result registers but
2281 // this is ok since the exception kills the result anyway).
2282
2283 if (is_at_poll_safepoint()) {
2284 // if the code we are returning to has deoptimized we must defer
2285 // the exception otherwise live registers get clobbered on the
2286 // exception path before deoptimization is able to retrieve them.
2287 //
2288 RegisterMap map(this, false);
2289 frame caller_fr = last_frame().sender(&map);
2290 assert(caller_fr.is_compiled_frame(), "what?");
2291 if (caller_fr.is_deoptimized_frame()) {
2292 log_info(exceptions)("deferred async exception at compiled safepoint");
2293 return;
2294 }
2295 }
2296 }
2297
2298 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2299 if (condition == _no_async_condition) {
2300 // Conditions have changed since has_special_runtime_exit_condition()
2301 // was called:
2302 // - if we were here only because of an external suspend request,
2303 // then that was taken care of above (or cancelled) so we are done
2304 // - if we were here because of another async request, then it has
2305 // been cleared between the has_special_runtime_exit_condition()
2306 // and now so again we are done
2307 return;
2308 }
2309
2310 // Check for pending async. exception
2311 if (_pending_async_exception != NULL) {
2312 // Only overwrite an already pending exception, if it is not a threadDeath.
2313 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2314
2315 // We cannot call Exceptions::_throw(...) here because we cannot block
2316 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2317
2318 LogTarget(Info, exceptions) lt;
2319 if (lt.is_enabled()) {
2320 ResourceMark rm;
2321 LogStream ls(lt);
2322 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2323 if (has_last_Java_frame()) {
2324 frame f = last_frame();
2325 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2326 }
2327 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2328 }
2329 _pending_async_exception = NULL;
2330 clear_has_async_exception();
2331 }
2332 }
2333
2334 if (check_unsafe_error &&
2335 condition == _async_unsafe_access_error && !has_pending_exception()) {
2336 condition = _no_async_condition; // done
2337 switch (thread_state()) {
2338 case _thread_in_vm: {
2339 JavaThread* THREAD = this;
2340 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2341 }
2342 case _thread_in_native: {
2343 ThreadInVMfromNative tiv(this);
2344 JavaThread* THREAD = this;
2345 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2346 }
2347 case _thread_in_Java: {
2348 ThreadInVMfromJava tiv(this);
2349 JavaThread* THREAD = this;
2350 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2351 }
2352 default:
2353 ShouldNotReachHere();
2354 }
2355 }
2356
2357 assert(condition == _no_async_condition || has_pending_exception() ||
2358 (!check_unsafe_error && condition == _async_unsafe_access_error),
2359 "must have handled the async condition, if no exception");
2360 }
2361
2362 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2363
2364 // Check for pending external suspend.
2365 if (is_external_suspend_with_lock()) {
2366 frame_anchor()->make_walkable(this);
2367 java_suspend_self_with_safepoint_check();
2368 }
2369
2370 // We might be here for reasons in addition to the self-suspend request
2371 // so check for other async requests.
2372 if (check_asyncs) {
2373 check_and_handle_async_exceptions();
2374 }
2375
2376 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2377 }
2378
2379 void JavaThread::send_thread_stop(oop java_throwable) {
2380 ResourceMark rm;
2381 assert(Thread::current()->is_VM_thread() || Thread::current() == this, "should be in the vm thread");
2382
2383 // Do not throw asynchronous exceptions against the compiler thread
2384 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2385 if (!can_call_java()) return;
2386
2387 {
2388 // Actually throw the Throwable against the target Thread - however
2389 // only if there is no thread death exception installed already.
2390 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2391 // If the topmost frame is a runtime stub, then we are calling into
2392 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2393 // must deoptimize the caller before continuing, as the compiled exception handler table
2394 // may not be valid
2395 if (has_last_Java_frame()) {
2396 frame f = last_frame();
2397 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2398 RegisterMap reg_map(this, false);
2399 frame compiled_frame = f.sender(®_map);
2400 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2401 Deoptimization::deoptimize(this, compiled_frame);
2402 }
2403 }
2404 }
2405
2406 // Set async. pending exception in thread.
2407 set_pending_async_exception(java_throwable);
2408
2409 if (log_is_enabled(Info, exceptions)) {
2410 ResourceMark rm;
2411 log_info(exceptions)("Pending Async. exception installed of type: %s",
2412 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2413 }
2414 // for AbortVMOnException flag
2415 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2416 }
2417 }
2418
2419
2420 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
2421 java_lang_Thread::set_interrupted(threadObj(), true);
2422 this->interrupt();
2423 }
2424
2425 // External suspension mechanism.
2426 //
2427 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2428 // to any VM_locks and it is at a transition
2429 // Self-suspension will happen on the transition out of the vm.
2430 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2431 //
2432 // Guarantees on return:
2433 // + Target thread will not execute any new bytecode (that's why we need to
2434 // force a safepoint)
2435 // + Target thread will not enter any new monitors
2436 //
2437 void JavaThread::java_suspend() {
2438 ThreadsListHandle tlh;
2439 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2440 return;
2441 }
2442
2443 { MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2444 if (!is_external_suspend()) {
2445 // a racing resume has cancelled us; bail out now
2446 return;
2447 }
2448
2449 // suspend is done
2450 uint32_t debug_bits = 0;
2451 // Warning: is_ext_suspend_completed() may temporarily drop the
2452 // SR_lock to allow the thread to reach a stable thread state if
2453 // it is currently in a transient thread state.
2454 if (is_ext_suspend_completed(false /* !called_by_wait */,
2455 SuspendRetryDelay, &debug_bits)) {
2456 return;
2457 }
2458 }
2459
2460 if (Thread::current() == this) {
2461 // Safely self-suspend.
2462 // If we don't do this explicitly it will implicitly happen
2463 // before we transition back to Java, and on some other thread-state
2464 // transition paths, but not as we exit a JVM TI SuspendThread call.
2465 // As SuspendThread(current) must not return (until resumed) we must
2466 // self-suspend here.
2467 ThreadBlockInVM tbivm(this);
2468 java_suspend_self();
2469 } else {
2470 VM_ThreadSuspend vm_suspend;
2471 VMThread::execute(&vm_suspend);
2472 }
2473 }
2474
2475 // Part II of external suspension.
2476 // A JavaThread self suspends when it detects a pending external suspend
2477 // request. This is usually on transitions. It is also done in places
2478 // where continuing to the next transition would surprise the caller,
2479 // e.g., monitor entry.
2480 //
2481 // Returns the number of times that the thread self-suspended.
2482 //
2483 // Note: DO NOT call java_suspend_self() when you just want to block current
2484 // thread. java_suspend_self() is the second stage of cooperative
2485 // suspension for external suspend requests and should only be used
2486 // to complete an external suspend request.
2487 //
2488 int JavaThread::java_suspend_self() {
2489 assert(thread_state() == _thread_blocked, "wrong state for java_suspend_self()");
2490 int ret = 0;
2491
2492 // we are in the process of exiting so don't suspend
2493 if (is_exiting()) {
2494 clear_external_suspend();
2495 return ret;
2496 }
2497
2498 assert(_anchor.walkable() ||
2499 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2500 "must have walkable stack");
2501
2502 MonitorLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2503
2504 assert(!this->is_ext_suspended(),
2505 "a thread trying to self-suspend should not already be suspended");
2506
2507 if (this->is_suspend_equivalent()) {
2508 // If we are self-suspending as a result of the lifting of a
2509 // suspend equivalent condition, then the suspend_equivalent
2510 // flag is not cleared until we set the ext_suspended flag so
2511 // that wait_for_ext_suspend_completion() returns consistent
2512 // results.
2513 this->clear_suspend_equivalent();
2514 }
2515
2516 // A racing resume may have cancelled us before we grabbed SR_lock
2517 // above. Or another external suspend request could be waiting for us
2518 // by the time we return from SR_lock()->wait(). The thread
2519 // that requested the suspension may already be trying to walk our
2520 // stack and if we return now, we can change the stack out from under
2521 // it. This would be a "bad thing (TM)" and cause the stack walker
2522 // to crash. We stay self-suspended until there are no more pending
2523 // external suspend requests.
2524 while (is_external_suspend()) {
2525 ret++;
2526 this->set_ext_suspended();
2527
2528 // _ext_suspended flag is cleared by java_resume()
2529 while (is_ext_suspended()) {
2530 ml.wait();
2531 }
2532 }
2533 return ret;
2534 }
2535
2536 // Helper routine to set up the correct thread state before calling java_suspend_self.
2537 // This is called when regular thread-state transition helpers can't be used because
2538 // we can be in various states, in particular _thread_in_native_trans.
2539 // Because this thread is external suspended the safepoint code will count it as at
2540 // a safepoint, regardless of what its actual current thread-state is. But
2541 // is_ext_suspend_completed() may be waiting to see a thread transition from
2542 // _thread_in_native_trans to _thread_blocked. So we set the thread state directly
2543 // to _thread_blocked. The problem with setting thread state directly is that a
2544 // safepoint could happen just after java_suspend_self() returns after being resumed,
2545 // and the VM thread will see the _thread_blocked state. So we must check for a safepoint
2546 // after restoring the state to make sure we won't leave while a safepoint is in progress.
2547 // However, not all initial-states are allowed when performing a safepoint check, as we
2548 // should never be blocking at a safepoint whilst in those states. Of these 'bad' states
2549 // only _thread_in_native is possible when executing this code (based on our two callers).
2550 // A thread that is _thread_in_native is already safepoint-safe and so it doesn't matter
2551 // whether the VMThread sees the _thread_blocked state, or the _thread_in_native state,
2552 // and so we don't need the explicit safepoint check.
2553
2554 void JavaThread::java_suspend_self_with_safepoint_check() {
2555 assert(this == Thread::current(), "invariant");
2556 JavaThreadState state = thread_state();
2557 set_thread_state(_thread_blocked);
2558 java_suspend_self();
2559 set_thread_state_fence(state);
2560 // Since we are not using a regular thread-state transition helper here,
2561 // we must manually emit the instruction barrier after leaving a safe state.
2562 OrderAccess::cross_modify_fence();
2563 if (state != _thread_in_native) {
2564 SafepointMechanism::block_if_requested(this);
2565 }
2566 }
2567
2568 #ifdef ASSERT
2569 // Verify the JavaThread has not yet been published in the Threads::list, and
2570 // hence doesn't need protection from concurrent access at this stage.
2571 void JavaThread::verify_not_published() {
2572 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2573 // since an unpublished JavaThread doesn't participate in the
2574 // Thread-SMR protocol for keeping a ThreadsList alive.
2575 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2576 }
2577 #endif
2578
2579 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2580 // progress or when _suspend_flags is non-zero.
2581 // Current thread needs to self-suspend if there is a suspend request and/or
2582 // block if a safepoint is in progress.
2583 // Async exception ISN'T checked.
2584 // Note only the ThreadInVMfromNative transition can call this function
2585 // directly and when thread state is _thread_in_native_trans
2586 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2587 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2588
2589 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2590
2591 if (thread->is_external_suspend()) {
2592 thread->java_suspend_self_with_safepoint_check();
2593 } else {
2594 SafepointMechanism::block_if_requested(thread);
2595 }
2596
2597 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2598 }
2599
2600 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2601 // progress or when _suspend_flags is non-zero.
2602 // Current thread needs to self-suspend if there is a suspend request and/or
2603 // block if a safepoint is in progress.
2604 // Also check for pending async exception (not including unsafe access error).
2605 // Note only the native==>VM/Java barriers can call this function and when
2606 // thread state is _thread_in_native_trans.
2607 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2608 check_safepoint_and_suspend_for_native_trans(thread);
2609
2610 if (thread->has_async_exception()) {
2611 // We are in _thread_in_native_trans state, don't handle unsafe
2612 // access error since that may block.
2613 thread->check_and_handle_async_exceptions(false);
2614 }
2615 }
2616
2617 // This is a variant of the normal
2618 // check_special_condition_for_native_trans with slightly different
2619 // semantics for use by critical native wrappers. It does all the
2620 // normal checks but also performs the transition back into
2621 // thread_in_Java state. This is required so that critical natives
2622 // can potentially block and perform a GC if they are the last thread
2623 // exiting the GCLocker.
2624 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2625 check_special_condition_for_native_trans(thread);
2626
2627 // Finish the transition
2628 thread->set_thread_state(_thread_in_Java);
2629
2630 if (thread->do_critical_native_unlock()) {
2631 ThreadInVMfromJavaNoAsyncException tiv(thread);
2632 GCLocker::unlock_critical(thread);
2633 thread->clear_critical_native_unlock();
2634 }
2635 }
2636
2637 // We need to guarantee the Threads_lock here, since resumes are not
2638 // allowed during safepoint synchronization
2639 // Can only resume from an external suspension
2640 void JavaThread::java_resume() {
2641 assert_locked_or_safepoint(Threads_lock);
2642
2643 // Sanity check: thread is gone, has started exiting or the thread
2644 // was not externally suspended.
2645 ThreadsListHandle tlh;
2646 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2647 return;
2648 }
2649
2650 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2651
2652 clear_external_suspend();
2653
2654 if (is_ext_suspended()) {
2655 clear_ext_suspended();
2656 SR_lock()->notify_all();
2657 }
2658 }
2659
2660 size_t JavaThread::_stack_red_zone_size = 0;
2661 size_t JavaThread::_stack_yellow_zone_size = 0;
2662 size_t JavaThread::_stack_reserved_zone_size = 0;
2663 size_t JavaThread::_stack_shadow_zone_size = 0;
2664
2665 void JavaThread::create_stack_guard_pages() {
2666 if (!os::uses_stack_guard_pages() ||
2667 _stack_guard_state != stack_guard_unused ||
2668 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2669 log_info(os, thread)("Stack guard page creation for thread "
2670 UINTX_FORMAT " disabled", os::current_thread_id());
2671 return;
2672 }
2673 address low_addr = stack_end();
2674 size_t len = stack_guard_zone_size();
2675
2676 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2677 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2678
2679 int must_commit = os::must_commit_stack_guard_pages();
2680 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2681
2682 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2683 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2684 return;
2685 }
2686
2687 if (os::guard_memory((char *) low_addr, len)) {
2688 _stack_guard_state = stack_guard_enabled;
2689 } else {
2690 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2691 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2692 if (os::uncommit_memory((char *) low_addr, len)) {
2693 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2694 }
2695 return;
2696 }
2697
2698 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2699 PTR_FORMAT "-" PTR_FORMAT ".",
2700 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2701 }
2702
2703 void JavaThread::remove_stack_guard_pages() {
2704 assert(Thread::current() == this, "from different thread");
2705 if (_stack_guard_state == stack_guard_unused) return;
2706 address low_addr = stack_end();
2707 size_t len = stack_guard_zone_size();
2708
2709 if (os::must_commit_stack_guard_pages()) {
2710 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2711 _stack_guard_state = stack_guard_unused;
2712 } else {
2713 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2714 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2715 return;
2716 }
2717 } else {
2718 if (_stack_guard_state == stack_guard_unused) return;
2719 if (os::unguard_memory((char *) low_addr, len)) {
2720 _stack_guard_state = stack_guard_unused;
2721 } else {
2722 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2723 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2724 return;
2725 }
2726 }
2727
2728 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2729 PTR_FORMAT "-" PTR_FORMAT ".",
2730 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2731 }
2732
2733 void JavaThread::enable_stack_reserved_zone() {
2734 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state");
2735
2736 // The base notation is from the stack's point of view, growing downward.
2737 // We need to adjust it to work correctly with guard_memory()
2738 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2739
2740 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2741 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2742
2743 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2744 _stack_guard_state = stack_guard_enabled;
2745 } else {
2746 warning("Attempt to guard stack reserved zone failed.");
2747 }
2748 enable_register_stack_guard();
2749 }
2750
2751 void JavaThread::disable_stack_reserved_zone() {
2752 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state");
2753
2754 // Simply return if called for a thread that does not use guard pages.
2755 if (_stack_guard_state != stack_guard_enabled) return;
2756
2757 // The base notation is from the stack's point of view, growing downward.
2758 // We need to adjust it to work correctly with guard_memory()
2759 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2760
2761 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2762 _stack_guard_state = stack_guard_reserved_disabled;
2763 } else {
2764 warning("Attempt to unguard stack reserved zone failed.");
2765 }
2766 disable_register_stack_guard();
2767 }
2768
2769 void JavaThread::enable_stack_yellow_reserved_zone() {
2770 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2771 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2772
2773 // The base notation is from the stacks point of view, growing downward.
2774 // We need to adjust it to work correctly with guard_memory()
2775 address base = stack_red_zone_base();
2776
2777 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2778 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2779
2780 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2781 _stack_guard_state = stack_guard_enabled;
2782 } else {
2783 warning("Attempt to guard stack yellow zone failed.");
2784 }
2785 enable_register_stack_guard();
2786 }
2787
2788 void JavaThread::disable_stack_yellow_reserved_zone() {
2789 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2790 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2791
2792 // Simply return if called for a thread that does not use guard pages.
2793 if (_stack_guard_state == stack_guard_unused) return;
2794
2795 // The base notation is from the stacks point of view, growing downward.
2796 // We need to adjust it to work correctly with guard_memory()
2797 address base = stack_red_zone_base();
2798
2799 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2800 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2801 } else {
2802 warning("Attempt to unguard stack yellow zone failed.");
2803 }
2804 disable_register_stack_guard();
2805 }
2806
2807 void JavaThread::enable_stack_red_zone() {
2808 // The base notation is from the stacks point of view, growing downward.
2809 // We need to adjust it to work correctly with guard_memory()
2810 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2811 address base = stack_red_zone_base() - stack_red_zone_size();
2812
2813 guarantee(base < stack_base(), "Error calculating stack red zone");
2814 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2815
2816 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2817 warning("Attempt to guard stack red zone failed.");
2818 }
2819 }
2820
2821 void JavaThread::disable_stack_red_zone() {
2822 // The base notation is from the stacks point of view, growing downward.
2823 // We need to adjust it to work correctly with guard_memory()
2824 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2825 address base = stack_red_zone_base() - stack_red_zone_size();
2826 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2827 warning("Attempt to unguard stack red zone failed.");
2828 }
2829 }
2830
2831 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2832 // ignore is there is no stack
2833 if (!has_last_Java_frame()) return;
2834 // traverse the stack frames. Starts from top frame.
2835 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2836 frame* fr = fst.current();
2837 f(fr, fst.register_map());
2838 }
2839 }
2840
2841
2842 #ifndef PRODUCT
2843 // Deoptimization
2844 // Function for testing deoptimization
2845 void JavaThread::deoptimize() {
2846 StackFrameStream fst(this, false);
2847 bool deopt = false; // Dump stack only if a deopt actually happens.
2848 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2849 // Iterate over all frames in the thread and deoptimize
2850 for (; !fst.is_done(); fst.next()) {
2851 if (fst.current()->can_be_deoptimized()) {
2852
2853 if (only_at) {
2854 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2855 // consists of comma or carriage return separated numbers so
2856 // search for the current bci in that string.
2857 address pc = fst.current()->pc();
2858 nmethod* nm = (nmethod*) fst.current()->cb();
2859 ScopeDesc* sd = nm->scope_desc_at(pc);
2860 char buffer[8];
2861 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2862 size_t len = strlen(buffer);
2863 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2864 while (found != NULL) {
2865 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2866 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2867 // Check that the bci found is bracketed by terminators.
2868 break;
2869 }
2870 found = strstr(found + 1, buffer);
2871 }
2872 if (!found) {
2873 continue;
2874 }
2875 }
2876
2877 if (DebugDeoptimization && !deopt) {
2878 deopt = true; // One-time only print before deopt
2879 tty->print_cr("[BEFORE Deoptimization]");
2880 trace_frames();
2881 trace_stack();
2882 }
2883 Deoptimization::deoptimize(this, *fst.current());
2884 }
2885 }
2886
2887 if (DebugDeoptimization && deopt) {
2888 tty->print_cr("[AFTER Deoptimization]");
2889 trace_frames();
2890 }
2891 }
2892
2893
2894 // Make zombies
2895 void JavaThread::make_zombies() {
2896 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2897 if (fst.current()->can_be_deoptimized()) {
2898 // it is a Java nmethod
2899 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2900 nm->make_not_entrant();
2901 }
2902 }
2903 }
2904 #endif // PRODUCT
2905
2906
2907 void JavaThread::deoptimize_marked_methods() {
2908 if (!has_last_Java_frame()) return;
2909 StackFrameStream fst(this, false);
2910 for (; !fst.is_done(); fst.next()) {
2911 if (fst.current()->should_be_deoptimized()) {
2912 Deoptimization::deoptimize(this, *fst.current());
2913 }
2914 }
2915 }
2916
2917 // If the caller is a NamedThread, then remember, in the current scope,
2918 // the given JavaThread in its _processed_thread field.
2919 class RememberProcessedThread: public StackObj {
2920 NamedThread* _cur_thr;
2921 public:
2922 RememberProcessedThread(JavaThread* jthr) {
2923 Thread* thread = Thread::current();
2924 if (thread->is_Named_thread()) {
2925 _cur_thr = (NamedThread *)thread;
2926 _cur_thr->set_processed_thread(jthr);
2927 } else {
2928 _cur_thr = NULL;
2929 }
2930 }
2931
2932 ~RememberProcessedThread() {
2933 if (_cur_thr) {
2934 _cur_thr->set_processed_thread(NULL);
2935 }
2936 }
2937 };
2938
2939 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2940 // Verify that the deferred card marks have been flushed.
2941 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2942
2943 // Traverse the GCHandles
2944 Thread::oops_do(f, cf);
2945
2946 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2947 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2948
2949 if (has_last_Java_frame()) {
2950 // Record JavaThread to GC thread
2951 RememberProcessedThread rpt(this);
2952
2953 // traverse the registered growable array
2954 if (_array_for_gc != NULL) {
2955 for (int index = 0; index < _array_for_gc->length(); index++) {
2956 f->do_oop(_array_for_gc->adr_at(index));
2957 }
2958 }
2959
2960 // Traverse the monitor chunks
2961 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2962 chunk->oops_do(f);
2963 }
2964
2965 // Traverse the execution stack
2966 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2967 fst.current()->oops_do(f, cf, fst.register_map());
2968 }
2969 }
2970
2971 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2972 // If we have deferred set_locals there might be oops waiting to be
2973 // written
2974 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2975 if (list != NULL) {
2976 for (int i = 0; i < list->length(); i++) {
2977 list->at(i)->oops_do(f);
2978 }
2979 }
2980
2981 // Traverse instance variables at the end since the GC may be moving things
2982 // around using this function
2983 f->do_oop((oop*) &_threadObj);
2984 f->do_oop((oop*) &_vm_result);
2985 f->do_oop((oop*) &_exception_oop);
2986 f->do_oop((oop*) &_pending_async_exception);
2987
2988 if (jvmti_thread_state() != NULL) {
2989 jvmti_thread_state()->oops_do(f, cf);
2990 }
2991 }
2992
2993 #ifdef ASSERT
2994 void JavaThread::verify_states_for_handshake() {
2995 // This checks that the thread has a correct frame state during a handshake.
2996 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2997 (has_last_Java_frame() && java_call_counter() > 0),
2998 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
2999 has_last_Java_frame(), java_call_counter());
3000 }
3001 #endif
3002
3003 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
3004 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
3005 (has_last_Java_frame() && java_call_counter() > 0),
3006 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
3007 has_last_Java_frame(), java_call_counter());
3008
3009 if (has_last_Java_frame()) {
3010 // Traverse the execution stack
3011 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3012 fst.current()->nmethods_do(cf);
3013 }
3014 }
3015
3016 if (jvmti_thread_state() != NULL) {
3017 jvmti_thread_state()->nmethods_do(cf);
3018 }
3019 }
3020
3021 void JavaThread::metadata_do(MetadataClosure* f) {
3022 if (has_last_Java_frame()) {
3023 // Traverse the execution stack to call f() on the methods in the stack
3024 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3025 fst.current()->metadata_do(f);
3026 }
3027 } else if (is_Compiler_thread()) {
3028 // need to walk ciMetadata in current compile tasks to keep alive.
3029 CompilerThread* ct = (CompilerThread*)this;
3030 if (ct->env() != NULL) {
3031 ct->env()->metadata_do(f);
3032 }
3033 CompileTask* task = ct->task();
3034 if (task != NULL) {
3035 task->metadata_do(f);
3036 }
3037 }
3038 }
3039
3040 // Printing
3041 const char* _get_thread_state_name(JavaThreadState _thread_state) {
3042 switch (_thread_state) {
3043 case _thread_uninitialized: return "_thread_uninitialized";
3044 case _thread_new: return "_thread_new";
3045 case _thread_new_trans: return "_thread_new_trans";
3046 case _thread_in_native: return "_thread_in_native";
3047 case _thread_in_native_trans: return "_thread_in_native_trans";
3048 case _thread_in_vm: return "_thread_in_vm";
3049 case _thread_in_vm_trans: return "_thread_in_vm_trans";
3050 case _thread_in_Java: return "_thread_in_Java";
3051 case _thread_in_Java_trans: return "_thread_in_Java_trans";
3052 case _thread_blocked: return "_thread_blocked";
3053 case _thread_blocked_trans: return "_thread_blocked_trans";
3054 default: return "unknown thread state";
3055 }
3056 }
3057
3058 #ifndef PRODUCT
3059 void JavaThread::print_thread_state_on(outputStream *st) const {
3060 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
3061 };
3062 #endif // PRODUCT
3063
3064 // Called by Threads::print() for VM_PrintThreads operation
3065 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
3066 st->print_raw("\"");
3067 st->print_raw(get_thread_name());
3068 st->print_raw("\" ");
3069 oop thread_oop = threadObj();
3070 if (thread_oop != NULL) {
3071 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
3072 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
3073 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
3074 }
3075 Thread::print_on(st, print_extended_info);
3076 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
3077 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
3078 if (thread_oop != NULL) {
3079 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3080 }
3081 #ifndef PRODUCT
3082 _safepoint_state->print_on(st);
3083 #endif // PRODUCT
3084 if (is_Compiler_thread()) {
3085 CompileTask *task = ((CompilerThread*)this)->task();
3086 if (task != NULL) {
3087 st->print(" Compiling: ");
3088 task->print(st, NULL, true, false);
3089 } else {
3090 st->print(" No compile task");
3091 }
3092 st->cr();
3093 }
3094 }
3095
3096 void JavaThread::print() const { print_on(tty); }
3097
3098 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3099 st->print("%s", get_thread_name_string(buf, buflen));
3100 }
3101
3102 // Called by fatal error handler. The difference between this and
3103 // JavaThread::print() is that we can't grab lock or allocate memory.
3104 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3105 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3106 oop thread_obj = threadObj();
3107 if (thread_obj != NULL) {
3108 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3109 }
3110 st->print(" [");
3111 st->print("%s", _get_thread_state_name(_thread_state));
3112 if (osthread()) {
3113 st->print(", id=%d", osthread()->thread_id());
3114 }
3115 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3116 p2i(stack_end()), p2i(stack_base()));
3117 st->print("]");
3118
3119 ThreadsSMRSupport::print_info_on(this, st);
3120 return;
3121 }
3122
3123 // Verification
3124
3125 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3126
3127 void JavaThread::verify() {
3128 // Verify oops in the thread.
3129 oops_do(&VerifyOopClosure::verify_oop, NULL);
3130
3131 // Verify the stack frames.
3132 frames_do(frame_verify);
3133 }
3134
3135 // CR 6300358 (sub-CR 2137150)
3136 // Most callers of this method assume that it can't return NULL but a
3137 // thread may not have a name whilst it is in the process of attaching to
3138 // the VM - see CR 6412693, and there are places where a JavaThread can be
3139 // seen prior to having it's threadObj set (eg JNI attaching threads and
3140 // if vm exit occurs during initialization). These cases can all be accounted
3141 // for such that this method never returns NULL.
3142 const char* JavaThread::get_thread_name() const {
3143 #ifdef ASSERT
3144 // early safepoints can hit while current thread does not yet have TLS
3145 if (!SafepointSynchronize::is_at_safepoint()) {
3146 Thread *cur = Thread::current();
3147 if (!(cur->is_Java_thread() && cur == this)) {
3148 // Current JavaThreads are allowed to get their own name without
3149 // the Threads_lock.
3150 assert_locked_or_safepoint_or_handshake(Threads_lock, this);
3151 }
3152 }
3153 #endif // ASSERT
3154 return get_thread_name_string();
3155 }
3156
3157 // Returns a non-NULL representation of this thread's name, or a suitable
3158 // descriptive string if there is no set name
3159 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3160 const char* name_str;
3161 oop thread_obj = threadObj();
3162 if (thread_obj != NULL) {
3163 oop name = java_lang_Thread::name(thread_obj);
3164 if (name != NULL) {
3165 if (buf == NULL) {
3166 name_str = java_lang_String::as_utf8_string(name);
3167 } else {
3168 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3169 }
3170 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3171 name_str = "<no-name - thread is attaching>";
3172 } else {
3173 name_str = Thread::name();
3174 }
3175 } else {
3176 name_str = Thread::name();
3177 }
3178 assert(name_str != NULL, "unexpected NULL thread name");
3179 return name_str;
3180 }
3181
3182 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3183
3184 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3185 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
3186 // Link Java Thread object <-> C++ Thread
3187
3188 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3189 // and put it into a new Handle. The Handle "thread_oop" can then
3190 // be used to pass the C++ thread object to other methods.
3191
3192 // Set the Java level thread object (jthread) field of the
3193 // new thread (a JavaThread *) to C++ thread object using the
3194 // "thread_oop" handle.
3195
3196 // Set the thread field (a JavaThread *) of the
3197 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3198
3199 Handle thread_oop(Thread::current(),
3200 JNIHandles::resolve_non_null(jni_thread));
3201 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3202 "must be initialized");
3203 set_threadObj(thread_oop());
3204 java_lang_Thread::set_thread(thread_oop(), this);
3205
3206 if (prio == NoPriority) {
3207 prio = java_lang_Thread::priority(thread_oop());
3208 assert(prio != NoPriority, "A valid priority should be present");
3209 }
3210
3211 // Push the Java priority down to the native thread; needs Threads_lock
3212 Thread::set_priority(this, prio);
3213
3214 // Add the new thread to the Threads list and set it in motion.
3215 // We must have threads lock in order to call Threads::add.
3216 // It is crucial that we do not block before the thread is
3217 // added to the Threads list for if a GC happens, then the java_thread oop
3218 // will not be visited by GC.
3219 Threads::add(this);
3220 }
3221
3222 oop JavaThread::current_park_blocker() {
3223 // Support for JSR-166 locks
3224 oop thread_oop = threadObj();
3225 if (thread_oop != NULL) {
3226 return java_lang_Thread::park_blocker(thread_oop);
3227 }
3228 return NULL;
3229 }
3230
3231
3232 void JavaThread::print_stack_on(outputStream* st) {
3233 if (!has_last_Java_frame()) return;
3234 ResourceMark rm;
3235 HandleMark hm;
3236
3237 RegisterMap reg_map(this);
3238 vframe* start_vf = last_java_vframe(®_map);
3239 int count = 0;
3240 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3241 if (f->is_java_frame()) {
3242 javaVFrame* jvf = javaVFrame::cast(f);
3243 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3244
3245 // Print out lock information
3246 if (JavaMonitorsInStackTrace) {
3247 jvf->print_lock_info_on(st, count);
3248 }
3249 } else {
3250 // Ignore non-Java frames
3251 }
3252
3253 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3254 count++;
3255 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3256 }
3257 }
3258
3259
3260 // JVMTI PopFrame support
3261 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3262 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3263 if (in_bytes(size_in_bytes) != 0) {
3264 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3265 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3266 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3267 }
3268 }
3269
3270 void* JavaThread::popframe_preserved_args() {
3271 return _popframe_preserved_args;
3272 }
3273
3274 ByteSize JavaThread::popframe_preserved_args_size() {
3275 return in_ByteSize(_popframe_preserved_args_size);
3276 }
3277
3278 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3279 int sz = in_bytes(popframe_preserved_args_size());
3280 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3281 return in_WordSize(sz / wordSize);
3282 }
3283
3284 void JavaThread::popframe_free_preserved_args() {
3285 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3286 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
3287 _popframe_preserved_args = NULL;
3288 _popframe_preserved_args_size = 0;
3289 }
3290
3291 #ifndef PRODUCT
3292
3293 void JavaThread::trace_frames() {
3294 tty->print_cr("[Describe stack]");
3295 int frame_no = 1;
3296 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3297 tty->print(" %d. ", frame_no++);
3298 fst.current()->print_value_on(tty, this);
3299 tty->cr();
3300 }
3301 }
3302
3303 class PrintAndVerifyOopClosure: public OopClosure {
3304 protected:
3305 template <class T> inline void do_oop_work(T* p) {
3306 oop obj = RawAccess<>::oop_load(p);
3307 if (obj == NULL) return;
3308 tty->print(INTPTR_FORMAT ": ", p2i(p));
3309 if (oopDesc::is_oop_or_null(obj)) {
3310 if (obj->is_objArray()) {
3311 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3312 } else {
3313 obj->print();
3314 }
3315 } else {
3316 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3317 }
3318 tty->cr();
3319 }
3320 public:
3321 virtual void do_oop(oop* p) { do_oop_work(p); }
3322 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3323 };
3324
3325 #ifdef ASSERT
3326 // Print or validate the layout of stack frames
3327 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3328 ResourceMark rm;
3329 PRESERVE_EXCEPTION_MARK;
3330 FrameValues values;
3331 int frame_no = 0;
3332 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3333 fst.current()->describe(values, ++frame_no);
3334 if (depth == frame_no) break;
3335 }
3336 if (validate_only) {
3337 values.validate();
3338 } else {
3339 tty->print_cr("[Describe stack layout]");
3340 values.print(this);
3341 }
3342 }
3343 #endif
3344
3345 void JavaThread::trace_stack_from(vframe* start_vf) {
3346 ResourceMark rm;
3347 int vframe_no = 1;
3348 for (vframe* f = start_vf; f; f = f->sender()) {
3349 if (f->is_java_frame()) {
3350 javaVFrame::cast(f)->print_activation(vframe_no++);
3351 } else {
3352 f->print();
3353 }
3354 if (vframe_no > StackPrintLimit) {
3355 tty->print_cr("...<more frames>...");
3356 return;
3357 }
3358 }
3359 }
3360
3361
3362 void JavaThread::trace_stack() {
3363 if (!has_last_Java_frame()) return;
3364 ResourceMark rm;
3365 HandleMark hm;
3366 RegisterMap reg_map(this);
3367 trace_stack_from(last_java_vframe(®_map));
3368 }
3369
3370
3371 #endif // PRODUCT
3372
3373
3374 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3375 assert(reg_map != NULL, "a map must be given");
3376 frame f = last_frame();
3377 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3378 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3379 }
3380 return NULL;
3381 }
3382
3383
3384 Klass* JavaThread::security_get_caller_class(int depth) {
3385 vframeStream vfst(this);
3386 vfst.security_get_caller_frame(depth);
3387 if (!vfst.at_end()) {
3388 return vfst.method()->method_holder();
3389 }
3390 return NULL;
3391 }
3392
3393 // java.lang.Thread.sleep support
3394 // Returns true if sleep time elapsed as expected, and false
3395 // if the thread was interrupted.
3396 bool JavaThread::sleep(jlong millis) {
3397 assert(this == Thread::current(), "thread consistency check");
3398
3399 ParkEvent * const slp = this->_SleepEvent;
3400 // Because there can be races with thread interruption sending an unpark()
3401 // to the event, we explicitly reset it here to avoid an immediate return.
3402 // The actual interrupt state will be checked before we park().
3403 slp->reset();
3404 // Thread interruption establishes a happens-before ordering in the
3405 // Java Memory Model, so we need to ensure we synchronize with the
3406 // interrupt state.
3407 OrderAccess::fence();
3408
3409 jlong prevtime = os::javaTimeNanos();
3410
3411 for (;;) {
3412 // interruption has precedence over timing out
3413 if (this->is_interrupted(true)) {
3414 return false;
3415 }
3416
3417 if (millis <= 0) {
3418 return true;
3419 }
3420
3421 {
3422 ThreadBlockInVM tbivm(this);
3423 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
3424
3425 this->set_suspend_equivalent();
3426 // cleared by handle_special_suspend_equivalent_condition() or
3427 // java_suspend_self() via check_and_wait_while_suspended()
3428
3429 slp->park(millis);
3430
3431 // were we externally suspended while we were waiting?
3432 this->check_and_wait_while_suspended();
3433 }
3434
3435 // Update elapsed time tracking
3436 jlong newtime = os::javaTimeNanos();
3437 if (newtime - prevtime < 0) {
3438 // time moving backwards, should only happen if no monotonic clock
3439 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3440 assert(!os::supports_monotonic_clock(),
3441 "unexpected time moving backwards detected in JavaThread::sleep()");
3442 } else {
3443 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3444 }
3445 prevtime = newtime;
3446 }
3447 }
3448
3449 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3450 assert(thread->is_Compiler_thread(), "must be compiler thread");
3451 CompileBroker::compiler_thread_loop();
3452 }
3453
3454 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3455 NMethodSweeper::sweeper_loop();
3456 }
3457
3458 // Create a CompilerThread
3459 CompilerThread::CompilerThread(CompileQueue* queue,
3460 CompilerCounters* counters)
3461 : JavaThread(&compiler_thread_entry) {
3462 _env = NULL;
3463 _log = NULL;
3464 _task = NULL;
3465 _queue = queue;
3466 _counters = counters;
3467 _buffer_blob = NULL;
3468 _compiler = NULL;
3469
3470 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3471 resource_area()->bias_to(mtCompiler);
3472
3473 #ifndef PRODUCT
3474 _ideal_graph_printer = NULL;
3475 #endif
3476 }
3477
3478 CompilerThread::~CompilerThread() {
3479 // Delete objects which were allocated on heap.
3480 delete _counters;
3481 }
3482
3483 bool CompilerThread::can_call_java() const {
3484 return _compiler != NULL && _compiler->is_jvmci();
3485 }
3486
3487 // Create sweeper thread
3488 CodeCacheSweeperThread::CodeCacheSweeperThread()
3489 : JavaThread(&sweeper_thread_entry) {
3490 _scanned_compiled_method = NULL;
3491 }
3492
3493 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3494 JavaThread::oops_do(f, cf);
3495 if (_scanned_compiled_method != NULL && cf != NULL) {
3496 // Safepoints can occur when the sweeper is scanning an nmethod so
3497 // process it here to make sure it isn't unloaded in the middle of
3498 // a scan.
3499 cf->do_code_blob(_scanned_compiled_method);
3500 }
3501 }
3502
3503 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3504 JavaThread::nmethods_do(cf);
3505 if (_scanned_compiled_method != NULL && cf != NULL) {
3506 // Safepoints can occur when the sweeper is scanning an nmethod so
3507 // process it here to make sure it isn't unloaded in the middle of
3508 // a scan.
3509 cf->do_code_blob(_scanned_compiled_method);
3510 }
3511 }
3512
3513
3514 // ======= Threads ========
3515
3516 // The Threads class links together all active threads, and provides
3517 // operations over all threads. It is protected by the Threads_lock,
3518 // which is also used in other global contexts like safepointing.
3519 // ThreadsListHandles are used to safely perform operations on one
3520 // or more threads without the risk of the thread exiting during the
3521 // operation.
3522 //
3523 // Note: The Threads_lock is currently more widely used than we
3524 // would like. We are actively migrating Threads_lock uses to other
3525 // mechanisms in order to reduce Threads_lock contention.
3526
3527 int Threads::_number_of_threads = 0;
3528 int Threads::_number_of_non_daemon_threads = 0;
3529 int Threads::_return_code = 0;
3530 uintx Threads::_thread_claim_token = 1; // Never zero.
3531 size_t JavaThread::_stack_size_at_create = 0;
3532
3533 #ifdef ASSERT
3534 bool Threads::_vm_complete = false;
3535 #endif
3536
3537 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3538 Prefetch::read((void*)addr, prefetch_interval);
3539 return *addr;
3540 }
3541
3542 // Possibly the ugliest for loop the world has seen. C++ does not allow
3543 // multiple types in the declaration section of the for loop. In this case
3544 // we are only dealing with pointers and hence can cast them. It looks ugly
3545 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3546 #define DO_JAVA_THREADS(LIST, X) \
3547 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3548 *MACRO_list = (JavaThread*)(LIST), \
3549 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3550 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3551 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3552 MACRO_current_p != MACRO_end; \
3553 MACRO_current_p++, \
3554 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3555
3556 // All JavaThreads
3557 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3558
3559 // All NonJavaThreads (i.e., every non-JavaThread in the system).
3560 void Threads::non_java_threads_do(ThreadClosure* tc) {
3561 NoSafepointVerifier nsv;
3562 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
3563 tc->do_thread(njti.current());
3564 }
3565 }
3566
3567 // All JavaThreads
3568 void Threads::java_threads_do(ThreadClosure* tc) {
3569 assert_locked_or_safepoint(Threads_lock);
3570 // ALL_JAVA_THREADS iterates through all JavaThreads.
3571 ALL_JAVA_THREADS(p) {
3572 tc->do_thread(p);
3573 }
3574 }
3575
3576 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3577 assert_locked_or_safepoint(Threads_lock);
3578 java_threads_do(tc);
3579 tc->do_thread(VMThread::vm_thread());
3580 }
3581
3582 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3583 void Threads::threads_do(ThreadClosure* tc) {
3584 assert_locked_or_safepoint(Threads_lock);
3585 java_threads_do(tc);
3586 non_java_threads_do(tc);
3587 }
3588
3589 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3590 uintx claim_token = Threads::thread_claim_token();
3591 ALL_JAVA_THREADS(p) {
3592 if (p->claim_threads_do(is_par, claim_token)) {
3593 tc->do_thread(p);
3594 }
3595 }
3596 VMThread* vmt = VMThread::vm_thread();
3597 if (vmt->claim_threads_do(is_par, claim_token)) {
3598 tc->do_thread(vmt);
3599 }
3600 }
3601
3602 // The system initialization in the library has three phases.
3603 //
3604 // Phase 1: java.lang.System class initialization
3605 // java.lang.System is a primordial class loaded and initialized
3606 // by the VM early during startup. java.lang.System.<clinit>
3607 // only does registerNatives and keeps the rest of the class
3608 // initialization work later until thread initialization completes.
3609 //
3610 // System.initPhase1 initializes the system properties, the static
3611 // fields in, out, and err. Set up java signal handlers, OS-specific
3612 // system settings, and thread group of the main thread.
3613 static void call_initPhase1(TRAPS) {
3614 Klass* klass = SystemDictionary::System_klass();
3615 JavaValue result(T_VOID);
3616 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3617 vmSymbols::void_method_signature(), CHECK);
3618 }
3619
3620 // Phase 2. Module system initialization
3621 // This will initialize the module system. Only java.base classes
3622 // can be loaded until phase 2 completes.
3623 //
3624 // Call System.initPhase2 after the compiler initialization and jsr292
3625 // classes get initialized because module initialization runs a lot of java
3626 // code, that for performance reasons, should be compiled. Also, this will
3627 // enable the startup code to use lambda and other language features in this
3628 // phase and onward.
3629 //
3630 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3631 static void call_initPhase2(TRAPS) {
3632 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3633
3634 Klass* klass = SystemDictionary::System_klass();
3635
3636 JavaValue result(T_INT);
3637 JavaCallArguments args;
3638 args.push_int(DisplayVMOutputToStderr);
3639 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3640 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3641 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3642 if (result.get_jint() != JNI_OK) {
3643 vm_exit_during_initialization(); // no message or exception
3644 }
3645
3646 universe_post_module_init();
3647 }
3648
3649 // Phase 3. final setup - set security manager, system class loader and TCCL
3650 //
3651 // This will instantiate and set the security manager, set the system class
3652 // loader as well as the thread context class loader. The security manager
3653 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3654 // other modules or the application's classpath.
3655 static void call_initPhase3(TRAPS) {
3656 Klass* klass = SystemDictionary::System_klass();
3657 JavaValue result(T_VOID);
3658 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3659 vmSymbols::void_method_signature(), CHECK);
3660 }
3661
3662 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3663 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3664
3665 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3666 create_vm_init_libraries();
3667 }
3668
3669 initialize_class(vmSymbols::java_lang_String(), CHECK);
3670
3671 // Inject CompactStrings value after the static initializers for String ran.
3672 java_lang_String::set_compact_strings(CompactStrings);
3673
3674 // Initialize java_lang.System (needed before creating the thread)
3675 initialize_class(vmSymbols::java_lang_System(), CHECK);
3676 // The VM creates & returns objects of this class. Make sure it's initialized.
3677 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3678 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3679 Handle thread_group = create_initial_thread_group(CHECK);
3680 Universe::set_main_thread_group(thread_group());
3681 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3682 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3683 main_thread->set_threadObj(thread_object);
3684
3685 // Set thread status to running since main thread has
3686 // been started and running.
3687 java_lang_Thread::set_thread_status(thread_object,
3688 java_lang_Thread::RUNNABLE);
3689
3690 // The VM creates objects of this class.
3691 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3692
3693 #ifdef ASSERT
3694 InstanceKlass *k = SystemDictionary::UnsafeConstants_klass();
3695 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
3696 #endif
3697
3698 // initialize the hardware-specific constants needed by Unsafe
3699 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
3700 jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
3701
3702 // The VM preresolves methods to these classes. Make sure that they get initialized
3703 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3704 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3705
3706 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3707 call_initPhase1(CHECK);
3708
3709 // get the Java runtime name, version, and vendor info after java.lang.System is initialized
3710 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3711 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3712 JDK_Version::set_runtime_vendor_version(get_java_runtime_vendor_version(THREAD));
3713 JDK_Version::set_runtime_vendor_vm_bug_url(get_java_runtime_vendor_vm_bug_url(THREAD));
3714
3715 // an instance of OutOfMemory exception has been allocated earlier
3716 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3717 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3718 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3719 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3720 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3721 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3722 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3723 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3724
3725 // Eager box cache initialization only if AOT is on and any library is loaded.
3726 AOTLoader::initialize_box_caches(CHECK);
3727 }
3728
3729 void Threads::initialize_jsr292_core_classes(TRAPS) {
3730 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3731
3732 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3733 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3734 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3735 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3736 }
3737
3738 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3739 extern void JDK_Version_init();
3740
3741 // Preinitialize version info.
3742 VM_Version::early_initialize();
3743
3744 // Check version
3745 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3746
3747 // Initialize library-based TLS
3748 ThreadLocalStorage::init();
3749
3750 // Initialize the output stream module
3751 ostream_init();
3752
3753 // Process java launcher properties.
3754 Arguments::process_sun_java_launcher_properties(args);
3755
3756 // Initialize the os module
3757 os::init();
3758
3759 // Record VM creation timing statistics
3760 TraceVmCreationTime create_vm_timer;
3761 create_vm_timer.start();
3762
3763 // Initialize system properties.
3764 Arguments::init_system_properties();
3765
3766 // So that JDK version can be used as a discriminator when parsing arguments
3767 JDK_Version_init();
3768
3769 // Update/Initialize System properties after JDK version number is known
3770 Arguments::init_version_specific_system_properties();
3771
3772 // Make sure to initialize log configuration *before* parsing arguments
3773 LogConfiguration::initialize(create_vm_timer.begin_time());
3774
3775 // Parse arguments
3776 // Note: this internally calls os::init_container_support()
3777 jint parse_result = Arguments::parse(args);
3778 if (parse_result != JNI_OK) return parse_result;
3779
3780 os::init_before_ergo();
3781
3782 jint ergo_result = Arguments::apply_ergo();
3783 if (ergo_result != JNI_OK) return ergo_result;
3784
3785 // Final check of all ranges after ergonomics which may change values.
3786 if (!JVMFlag::check_all_ranges()) {
3787 return JNI_EINVAL;
3788 }
3789
3790 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3791 bool constraint_result = JVMFlag::check_all_constraints(JVMFlag::AfterErgo);
3792 if (!constraint_result) {
3793 return JNI_EINVAL;
3794 }
3795
3796 if (PauseAtStartup) {
3797 os::pause();
3798 }
3799
3800 HOTSPOT_VM_INIT_BEGIN();
3801
3802 // Timing (must come after argument parsing)
3803 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3804
3805 // Initialize the os module after parsing the args
3806 jint os_init_2_result = os::init_2();
3807 if (os_init_2_result != JNI_OK) return os_init_2_result;
3808
3809 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3810 // Initialize assert poison page mechanism.
3811 if (ShowRegistersOnAssert) {
3812 initialize_assert_poison();
3813 }
3814 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3815
3816 SafepointMechanism::initialize();
3817
3818 jint adjust_after_os_result = Arguments::adjust_after_os();
3819 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3820
3821 // Initialize output stream logging
3822 ostream_init_log();
3823
3824 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3825 // Must be before create_vm_init_agents()
3826 if (Arguments::init_libraries_at_startup()) {
3827 convert_vm_init_libraries_to_agents();
3828 }
3829
3830 // Launch -agentlib/-agentpath and converted -Xrun agents
3831 if (Arguments::init_agents_at_startup()) {
3832 create_vm_init_agents();
3833 }
3834
3835 // Initialize Threads state
3836 _number_of_threads = 0;
3837 _number_of_non_daemon_threads = 0;
3838
3839 // Initialize global data structures and create system classes in heap
3840 vm_init_globals();
3841
3842 #if INCLUDE_JVMCI
3843 if (JVMCICounterSize > 0) {
3844 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
3845 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3846 } else {
3847 JavaThread::_jvmci_old_thread_counters = NULL;
3848 }
3849 #endif // INCLUDE_JVMCI
3850
3851 // Attach the main thread to this os thread
3852 JavaThread* main_thread = new JavaThread();
3853 main_thread->set_thread_state(_thread_in_vm);
3854 main_thread->initialize_thread_current();
3855 // must do this before set_active_handles
3856 main_thread->record_stack_base_and_size();
3857 main_thread->register_thread_stack_with_NMT();
3858 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3859
3860 if (!main_thread->set_as_starting_thread()) {
3861 vm_shutdown_during_initialization(
3862 "Failed necessary internal allocation. Out of swap space");
3863 main_thread->smr_delete();
3864 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3865 return JNI_ENOMEM;
3866 }
3867
3868 // Enable guard page *after* os::create_main_thread(), otherwise it would
3869 // crash Linux VM, see notes in os_linux.cpp.
3870 main_thread->create_stack_guard_pages();
3871
3872 // Initialize Java-Level synchronization subsystem
3873 ObjectMonitor::Initialize();
3874
3875 // Initialize global modules
3876 jint status = init_globals();
3877 if (status != JNI_OK) {
3878 main_thread->smr_delete();
3879 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3880 return status;
3881 }
3882
3883 JFR_ONLY(Jfr::on_create_vm_1();)
3884
3885 // Should be done after the heap is fully created
3886 main_thread->cache_global_variables();
3887
3888 HandleMark hm;
3889
3890 { MutexLocker mu(Threads_lock);
3891 Threads::add(main_thread);
3892 }
3893
3894 // Any JVMTI raw monitors entered in onload will transition into
3895 // real raw monitor. VM is setup enough here for raw monitor enter.
3896 JvmtiExport::transition_pending_onload_raw_monitors();
3897
3898 // Create the VMThread
3899 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3900
3901 VMThread::create();
3902 Thread* vmthread = VMThread::vm_thread();
3903
3904 if (!os::create_thread(vmthread, os::vm_thread)) {
3905 vm_exit_during_initialization("Cannot create VM thread. "
3906 "Out of system resources.");
3907 }
3908
3909 // Wait for the VM thread to become ready, and VMThread::run to initialize
3910 // Monitors can have spurious returns, must always check another state flag
3911 {
3912 MonitorLocker ml(Notify_lock);
3913 os::start_thread(vmthread);
3914 while (vmthread->active_handles() == NULL) {
3915 ml.wait();
3916 }
3917 }
3918 }
3919
3920 assert(Universe::is_fully_initialized(), "not initialized");
3921 if (VerifyDuringStartup) {
3922 // Make sure we're starting with a clean slate.
3923 VM_Verify verify_op;
3924 VMThread::execute(&verify_op);
3925 }
3926
3927 // We need this to update the java.vm.info property in case any flags used
3928 // to initially define it have been changed. This is needed for both CDS and
3929 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info
3930 // is initially computed. See Abstract_VM_Version::vm_info_string().
3931 // This update must happen before we initialize the java classes, but
3932 // after any initialization logic that might modify the flags.
3933 Arguments::update_vm_info_property(VM_Version::vm_info_string());
3934
3935 Thread* THREAD = Thread::current();
3936
3937 // Always call even when there are not JVMTI environments yet, since environments
3938 // may be attached late and JVMTI must track phases of VM execution
3939 JvmtiExport::enter_early_start_phase();
3940
3941 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3942 JvmtiExport::post_early_vm_start();
3943
3944 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3945
3946 quicken_jni_functions();
3947
3948 // No more stub generation allowed after that point.
3949 StubCodeDesc::freeze();
3950
3951 // Set flag that basic initialization has completed. Used by exceptions and various
3952 // debug stuff, that does not work until all basic classes have been initialized.
3953 set_init_completed();
3954
3955 LogConfiguration::post_initialize();
3956 Metaspace::post_initialize();
3957
3958 HOTSPOT_VM_INIT_END();
3959
3960 // record VM initialization completion time
3961 #if INCLUDE_MANAGEMENT
3962 Management::record_vm_init_completed();
3963 #endif // INCLUDE_MANAGEMENT
3964
3965 // Signal Dispatcher needs to be started before VMInit event is posted
3966 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3967
3968 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3969 if (!DisableAttachMechanism) {
3970 AttachListener::vm_start();
3971 if (StartAttachListener || AttachListener::init_at_startup()) {
3972 AttachListener::init();
3973 }
3974 }
3975
3976 // Launch -Xrun agents
3977 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3978 // back-end can launch with -Xdebug -Xrunjdwp.
3979 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3980 create_vm_init_libraries();
3981 }
3982
3983 if (CleanChunkPoolAsync) {
3984 Chunk::start_chunk_pool_cleaner_task();
3985 }
3986
3987 // Start the service thread
3988 // The service thread enqueues JVMTI deferred events and does various hashtable
3989 // and other cleanups. Needs to start before the compilers start posting events.
3990 ServiceThread::initialize();
3991
3992 // initialize compiler(s)
3993 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3994 #if INCLUDE_JVMCI
3995 bool force_JVMCI_intialization = false;
3996 if (EnableJVMCI) {
3997 // Initialize JVMCI eagerly when it is explicitly requested.
3998 // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
3999 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
4000
4001 if (!force_JVMCI_intialization) {
4002 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
4003 // compilations via JVMCI will not actually block until JVMCI is initialized.
4004 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
4005 }
4006 }
4007 #endif
4008 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
4009 // Postpone completion of compiler initialization to after JVMCI
4010 // is initialized to avoid timeouts of blocking compilations.
4011 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
4012 CompileBroker::compilation_init_phase2();
4013 }
4014 #endif
4015
4016 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
4017 // It is done after compilers are initialized, because otherwise compilations of
4018 // signature polymorphic MH intrinsics can be missed
4019 // (see SystemDictionary::find_method_handle_intrinsic).
4020 initialize_jsr292_core_classes(CHECK_JNI_ERR);
4021
4022 // This will initialize the module system. Only java.base classes can be
4023 // loaded until phase 2 completes
4024 call_initPhase2(CHECK_JNI_ERR);
4025
4026 JFR_ONLY(Jfr::on_create_vm_2();)
4027
4028 // Always call even when there are not JVMTI environments yet, since environments
4029 // may be attached late and JVMTI must track phases of VM execution
4030 JvmtiExport::enter_start_phase();
4031
4032 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
4033 JvmtiExport::post_vm_start();
4034
4035 // Final system initialization including security manager and system class loader
4036 call_initPhase3(CHECK_JNI_ERR);
4037
4038 // cache the system and platform class loaders
4039 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
4040
4041 #if INCLUDE_CDS
4042 // capture the module path info from the ModuleEntryTable
4043 ClassLoader::initialize_module_path(THREAD);
4044 #endif
4045
4046 #if INCLUDE_JVMCI
4047 if (force_JVMCI_intialization) {
4048 JVMCI::initialize_compiler(CHECK_JNI_ERR);
4049 CompileBroker::compilation_init_phase2();
4050 }
4051 #endif
4052
4053 // Always call even when there are not JVMTI environments yet, since environments
4054 // may be attached late and JVMTI must track phases of VM execution
4055 JvmtiExport::enter_live_phase();
4056
4057 // Make perfmemory accessible
4058 PerfMemory::set_accessible(true);
4059
4060 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
4061 JvmtiExport::post_vm_initialized();
4062
4063 JFR_ONLY(Jfr::on_create_vm_3();)
4064
4065 #if INCLUDE_MANAGEMENT
4066 Management::initialize(THREAD);
4067
4068 if (HAS_PENDING_EXCEPTION) {
4069 // management agent fails to start possibly due to
4070 // configuration problem and is responsible for printing
4071 // stack trace if appropriate. Simply exit VM.
4072 vm_exit(1);
4073 }
4074 #endif // INCLUDE_MANAGEMENT
4075
4076 if (MemProfiling) MemProfiler::engage();
4077 StatSampler::engage();
4078 if (CheckJNICalls) JniPeriodicChecker::engage();
4079
4080 BiasedLocking::init();
4081
4082 #if INCLUDE_RTM_OPT
4083 RTMLockingCounters::init();
4084 #endif
4085
4086 call_postVMInitHook(THREAD);
4087 // The Java side of PostVMInitHook.run must deal with all
4088 // exceptions and provide means of diagnosis.
4089 if (HAS_PENDING_EXCEPTION) {
4090 CLEAR_PENDING_EXCEPTION;
4091 }
4092
4093 {
4094 MutexLocker ml(PeriodicTask_lock);
4095 // Make sure the WatcherThread can be started by WatcherThread::start()
4096 // or by dynamic enrollment.
4097 WatcherThread::make_startable();
4098 // Start up the WatcherThread if there are any periodic tasks
4099 // NOTE: All PeriodicTasks should be registered by now. If they
4100 // aren't, late joiners might appear to start slowly (we might
4101 // take a while to process their first tick).
4102 if (PeriodicTask::num_tasks() > 0) {
4103 WatcherThread::start();
4104 }
4105 }
4106
4107 create_vm_timer.end();
4108 #ifdef ASSERT
4109 _vm_complete = true;
4110 #endif
4111
4112 if (DumpSharedSpaces) {
4113 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
4114 ShouldNotReachHere();
4115 }
4116
4117 return JNI_OK;
4118 }
4119
4120 // type for the Agent_OnLoad and JVM_OnLoad entry points
4121 extern "C" {
4122 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
4123 }
4124 // Find a command line agent library and return its entry point for
4125 // -agentlib: -agentpath: -Xrun
4126 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
4127 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
4128 const char *on_load_symbols[],
4129 size_t num_symbol_entries) {
4130 OnLoadEntry_t on_load_entry = NULL;
4131 void *library = NULL;
4132
4133 if (!agent->valid()) {
4134 char buffer[JVM_MAXPATHLEN];
4135 char ebuf[1024] = "";
4136 const char *name = agent->name();
4137 const char *msg = "Could not find agent library ";
4138
4139 // First check to see if agent is statically linked into executable
4140 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
4141 library = agent->os_lib();
4142 } else if (agent->is_absolute_path()) {
4143 library = os::dll_load(name, ebuf, sizeof ebuf);
4144 if (library == NULL) {
4145 const char *sub_msg = " in absolute path, with error: ";
4146 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4147 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4148 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4149 // If we can't find the agent, exit.
4150 vm_exit_during_initialization(buf, NULL);
4151 FREE_C_HEAP_ARRAY(char, buf);
4152 }
4153 } else {
4154 // Try to load the agent from the standard dll directory
4155 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4156 name)) {
4157 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4158 }
4159 if (library == NULL) { // Try the library path directory.
4160 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4161 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4162 }
4163 if (library == NULL) {
4164 const char *sub_msg = " on the library path, with error: ";
4165 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4166
4167 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4168 strlen(ebuf) + strlen(sub_msg2) + 1;
4169 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4170 if (!agent->is_instrument_lib()) {
4171 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4172 } else {
4173 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4174 }
4175 // If we can't find the agent, exit.
4176 vm_exit_during_initialization(buf, NULL);
4177 FREE_C_HEAP_ARRAY(char, buf);
4178 }
4179 }
4180 }
4181 agent->set_os_lib(library);
4182 agent->set_valid();
4183 }
4184
4185 // Find the OnLoad function.
4186 on_load_entry =
4187 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4188 false,
4189 on_load_symbols,
4190 num_symbol_entries));
4191 return on_load_entry;
4192 }
4193
4194 // Find the JVM_OnLoad entry point
4195 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4196 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4197 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4198 }
4199
4200 // Find the Agent_OnLoad entry point
4201 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4202 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4203 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4204 }
4205
4206 // For backwards compatibility with -Xrun
4207 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4208 // treated like -agentpath:
4209 // Must be called before agent libraries are created
4210 void Threads::convert_vm_init_libraries_to_agents() {
4211 AgentLibrary* agent;
4212 AgentLibrary* next;
4213
4214 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4215 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4216 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4217
4218 // If there is an JVM_OnLoad function it will get called later,
4219 // otherwise see if there is an Agent_OnLoad
4220 if (on_load_entry == NULL) {
4221 on_load_entry = lookup_agent_on_load(agent);
4222 if (on_load_entry != NULL) {
4223 // switch it to the agent list -- so that Agent_OnLoad will be called,
4224 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4225 Arguments::convert_library_to_agent(agent);
4226 } else {
4227 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4228 }
4229 }
4230 }
4231 }
4232
4233 // Create agents for -agentlib: -agentpath: and converted -Xrun
4234 // Invokes Agent_OnLoad
4235 // Called very early -- before JavaThreads exist
4236 void Threads::create_vm_init_agents() {
4237 extern struct JavaVM_ main_vm;
4238 AgentLibrary* agent;
4239
4240 JvmtiExport::enter_onload_phase();
4241
4242 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4243 // CDS dumping does not support native JVMTI agent.
4244 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
4245 if (Arguments::is_dumping_archive()) {
4246 if(!agent->is_instrument_lib()) {
4247 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
4248 } else if (!AllowArchivingWithJavaAgent) {
4249 vm_exit_during_cds_dumping(
4250 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
4251 }
4252 }
4253
4254 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4255
4256 if (on_load_entry != NULL) {
4257 // Invoke the Agent_OnLoad function
4258 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4259 if (err != JNI_OK) {
4260 vm_exit_during_initialization("agent library failed to init", agent->name());
4261 }
4262 } else {
4263 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4264 }
4265 }
4266
4267 JvmtiExport::enter_primordial_phase();
4268 }
4269
4270 extern "C" {
4271 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4272 }
4273
4274 void Threads::shutdown_vm_agents() {
4275 // Send any Agent_OnUnload notifications
4276 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4277 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4278 extern struct JavaVM_ main_vm;
4279 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4280
4281 // Find the Agent_OnUnload function.
4282 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4283 os::find_agent_function(agent,
4284 false,
4285 on_unload_symbols,
4286 num_symbol_entries));
4287
4288 // Invoke the Agent_OnUnload function
4289 if (unload_entry != NULL) {
4290 JavaThread* thread = JavaThread::current();
4291 ThreadToNativeFromVM ttn(thread);
4292 HandleMark hm(thread);
4293 (*unload_entry)(&main_vm);
4294 }
4295 }
4296 }
4297
4298 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4299 // Invokes JVM_OnLoad
4300 void Threads::create_vm_init_libraries() {
4301 extern struct JavaVM_ main_vm;
4302 AgentLibrary* agent;
4303
4304 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4305 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4306
4307 if (on_load_entry != NULL) {
4308 // Invoke the JVM_OnLoad function
4309 JavaThread* thread = JavaThread::current();
4310 ThreadToNativeFromVM ttn(thread);
4311 HandleMark hm(thread);
4312 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4313 if (err != JNI_OK) {
4314 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4315 }
4316 } else {
4317 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4318 }
4319 }
4320 }
4321
4322
4323 // Last thread running calls java.lang.Shutdown.shutdown()
4324 void JavaThread::invoke_shutdown_hooks() {
4325 HandleMark hm(this);
4326
4327 // Link all classes for dynamic CDS dumping before vm exit.
4328 // Same operation is being done in JVM_BeforeHalt for handling the
4329 // case where the application calls System.exit().
4330 if (DynamicDumpSharedSpaces) {
4331 MetaspaceShared::link_and_cleanup_shared_classes(this);
4332 }
4333
4334 // We could get here with a pending exception, if so clear it now.
4335 if (this->has_pending_exception()) {
4336 this->clear_pending_exception();
4337 }
4338
4339 EXCEPTION_MARK;
4340 Klass* shutdown_klass =
4341 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4342 THREAD);
4343 if (shutdown_klass != NULL) {
4344 // SystemDictionary::resolve_or_null will return null if there was
4345 // an exception. If we cannot load the Shutdown class, just don't
4346 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4347 // won't be run. Note that if a shutdown hook was registered,
4348 // the Shutdown class would have already been loaded
4349 // (Runtime.addShutdownHook will load it).
4350 JavaValue result(T_VOID);
4351 JavaCalls::call_static(&result,
4352 shutdown_klass,
4353 vmSymbols::shutdown_name(),
4354 vmSymbols::void_method_signature(),
4355 THREAD);
4356 }
4357 CLEAR_PENDING_EXCEPTION;
4358 }
4359
4360 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4361 // the program falls off the end of main(). Another VM exit path is through
4362 // vm_exit() when the program calls System.exit() to return a value or when
4363 // there is a serious error in VM. The two shutdown paths are not exactly
4364 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4365 // and VM_Exit op at VM level.
4366 //
4367 // Shutdown sequence:
4368 // + Shutdown native memory tracking if it is on
4369 // + Wait until we are the last non-daemon thread to execute
4370 // <-- every thing is still working at this moment -->
4371 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4372 // shutdown hooks
4373 // + Call before_exit(), prepare for VM exit
4374 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4375 // currently the only user of this mechanism is File.deleteOnExit())
4376 // > stop StatSampler, watcher thread,
4377 // post thread end and vm death events to JVMTI,
4378 // stop signal thread
4379 // + Call JavaThread::exit(), it will:
4380 // > release JNI handle blocks, remove stack guard pages
4381 // > remove this thread from Threads list
4382 // <-- no more Java code from this thread after this point -->
4383 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4384 // the compiler threads at safepoint
4385 // <-- do not use anything that could get blocked by Safepoint -->
4386 // + Disable tracing at JNI/JVM barriers
4387 // + Set _vm_exited flag for threads that are still running native code
4388 // + Call exit_globals()
4389 // > deletes tty
4390 // > deletes PerfMemory resources
4391 // + Delete this thread
4392 // + Return to caller
4393
4394 bool Threads::destroy_vm() {
4395 JavaThread* thread = JavaThread::current();
4396
4397 #ifdef ASSERT
4398 _vm_complete = false;
4399 #endif
4400 // Wait until we are the last non-daemon thread to execute
4401 { MonitorLocker nu(Threads_lock);
4402 while (Threads::number_of_non_daemon_threads() > 1)
4403 // This wait should make safepoint checks, wait without a timeout,
4404 // and wait as a suspend-equivalent condition.
4405 nu.wait(0, Mutex::_as_suspend_equivalent_flag);
4406 }
4407
4408 EventShutdown e;
4409 if (e.should_commit()) {
4410 e.set_reason("No remaining non-daemon Java threads");
4411 e.commit();
4412 }
4413
4414 // Hang forever on exit if we are reporting an error.
4415 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4416 os::infinite_sleep();
4417 }
4418 os::wait_for_keypress_at_exit();
4419
4420 // run Java level shutdown hooks
4421 thread->invoke_shutdown_hooks();
4422
4423 before_exit(thread);
4424
4425 thread->exit(true);
4426
4427 // Stop VM thread.
4428 {
4429 // 4945125 The vm thread comes to a safepoint during exit.
4430 // GC vm_operations can get caught at the safepoint, and the
4431 // heap is unparseable if they are caught. Grab the Heap_lock
4432 // to prevent this. The GC vm_operations will not be able to
4433 // queue until after the vm thread is dead. After this point,
4434 // we'll never emerge out of the safepoint before the VM exits.
4435
4436 MutexLocker ml(Heap_lock, Mutex::_no_safepoint_check_flag);
4437
4438 VMThread::wait_for_vm_thread_exit();
4439 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4440 VMThread::destroy();
4441 }
4442
4443 // Now, all Java threads are gone except daemon threads. Daemon threads
4444 // running Java code or in VM are stopped by the Safepoint. However,
4445 // daemon threads executing native code are still running. But they
4446 // will be stopped at native=>Java/VM barriers. Note that we can't
4447 // simply kill or suspend them, as it is inherently deadlock-prone.
4448
4449 VM_Exit::set_vm_exited();
4450
4451 // Clean up ideal graph printers after the VMThread has started
4452 // the final safepoint which will block all the Compiler threads.
4453 // Note that this Thread has already logically exited so the
4454 // clean_up() function's use of a JavaThreadIteratorWithHandle
4455 // would be a problem except set_vm_exited() has remembered the
4456 // shutdown thread which is granted a policy exception.
4457 #if defined(COMPILER2) && !defined(PRODUCT)
4458 IdealGraphPrinter::clean_up();
4459 #endif
4460
4461 notify_vm_shutdown();
4462
4463 // exit_globals() will delete tty
4464 exit_globals();
4465
4466 // We are after VM_Exit::set_vm_exited() so we can't call
4467 // thread->smr_delete() or we will block on the Threads_lock.
4468 // Deleting the shutdown thread here is safe because another
4469 // JavaThread cannot have an active ThreadsListHandle for
4470 // this JavaThread.
4471 delete thread;
4472
4473 #if INCLUDE_JVMCI
4474 if (JVMCICounterSize > 0) {
4475 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4476 }
4477 #endif
4478
4479 LogConfiguration::finalize();
4480
4481 return true;
4482 }
4483
4484
4485 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4486 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4487 return is_supported_jni_version(version);
4488 }
4489
4490
4491 jboolean Threads::is_supported_jni_version(jint version) {
4492 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4493 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4494 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4495 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4496 if (version == JNI_VERSION_9) return JNI_TRUE;
4497 if (version == JNI_VERSION_10) return JNI_TRUE;
4498 return JNI_FALSE;
4499 }
4500
4501
4502 void Threads::add(JavaThread* p, bool force_daemon) {
4503 // The threads lock must be owned at this point
4504 assert(Threads_lock->owned_by_self(), "must have threads lock");
4505
4506 BarrierSet::barrier_set()->on_thread_attach(p);
4507
4508 // Once a JavaThread is added to the Threads list, smr_delete() has
4509 // to be used to delete it. Otherwise we can just delete it directly.
4510 p->set_on_thread_list();
4511
4512 _number_of_threads++;
4513 oop threadObj = p->threadObj();
4514 bool daemon = true;
4515 // Bootstrapping problem: threadObj can be null for initial
4516 // JavaThread (or for threads attached via JNI)
4517 if ((!force_daemon) && !is_daemon((threadObj))) {
4518 _number_of_non_daemon_threads++;
4519 daemon = false;
4520 }
4521
4522 ThreadService::add_thread(p, daemon);
4523
4524 // Maintain fast thread list
4525 ThreadsSMRSupport::add_thread(p);
4526
4527 // Possible GC point.
4528 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4529 }
4530
4531 void Threads::remove(JavaThread* p, bool is_daemon) {
4532
4533 // Reclaim the ObjectMonitors from the om_in_use_list and om_free_list of the moribund thread.
4534 ObjectSynchronizer::om_flush(p);
4535
4536 // Extra scope needed for Thread_lock, so we can check
4537 // that we do not remove thread without safepoint code notice
4538 { MonitorLocker ml(Threads_lock);
4539
4540 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4541
4542 // Maintain fast thread list
4543 ThreadsSMRSupport::remove_thread(p);
4544
4545 _number_of_threads--;
4546 if (!is_daemon) {
4547 _number_of_non_daemon_threads--;
4548
4549 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4550 // on destroy_vm will wake up.
4551 if (number_of_non_daemon_threads() == 1) {
4552 ml.notify_all();
4553 }
4554 }
4555 ThreadService::remove_thread(p, is_daemon);
4556
4557 // Make sure that safepoint code disregard this thread. This is needed since
4558 // the thread might mess around with locks after this point. This can cause it
4559 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4560 // of this thread since it is removed from the queue.
4561 p->set_terminated_value();
4562 } // unlock Threads_lock
4563
4564 // Since Events::log uses a lock, we grab it outside the Threads_lock
4565 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4566 }
4567
4568 // Operations on the Threads list for GC. These are not explicitly locked,
4569 // but the garbage collector must provide a safe context for them to run.
4570 // In particular, these things should never be called when the Threads_lock
4571 // is held by some other thread. (Note: the Safepoint abstraction also
4572 // uses the Threads_lock to guarantee this property. It also makes sure that
4573 // all threads gets blocked when exiting or starting).
4574
4575 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4576 ALL_JAVA_THREADS(p) {
4577 p->oops_do(f, cf);
4578 }
4579 VMThread::vm_thread()->oops_do(f, cf);
4580 }
4581
4582 void Threads::change_thread_claim_token() {
4583 if (++_thread_claim_token == 0) {
4584 // On overflow of the token counter, there is a risk of future
4585 // collisions between a new global token value and a stale token
4586 // for a thread, because not all iterations visit all threads.
4587 // (Though it's pretty much a theoretical concern for non-trivial
4588 // token counter sizes.) To deal with the possibility, reset all
4589 // the thread tokens to zero on global token overflow.
4590 struct ResetClaims : public ThreadClosure {
4591 virtual void do_thread(Thread* t) {
4592 t->claim_threads_do(false, 0);
4593 }
4594 } reset_claims;
4595 Threads::threads_do(&reset_claims);
4596 // On overflow, update the global token to non-zero, to
4597 // avoid the special "never claimed" initial thread value.
4598 _thread_claim_token = 1;
4599 }
4600 }
4601
4602 #ifdef ASSERT
4603 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
4604 const uintx token = t->threads_do_token();
4605 assert(token == expected,
4606 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
4607 UINTX_FORMAT, kind, p2i(t), token, expected);
4608 }
4609
4610 void Threads::assert_all_threads_claimed() {
4611 ALL_JAVA_THREADS(p) {
4612 assert_thread_claimed("Thread", p, _thread_claim_token);
4613 }
4614 assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token);
4615 }
4616 #endif // ASSERT
4617
4618 class ParallelOopsDoThreadClosure : public ThreadClosure {
4619 private:
4620 OopClosure* _f;
4621 CodeBlobClosure* _cf;
4622 public:
4623 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4624 void do_thread(Thread* t) {
4625 t->oops_do(_f, _cf);
4626 }
4627 };
4628
4629 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4630 ParallelOopsDoThreadClosure tc(f, cf);
4631 possibly_parallel_threads_do(is_par, &tc);
4632 }
4633
4634 void Threads::nmethods_do(CodeBlobClosure* cf) {
4635 ALL_JAVA_THREADS(p) {
4636 // This is used by the code cache sweeper to mark nmethods that are active
4637 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4638 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4639 if(!p->is_Code_cache_sweeper_thread()) {
4640 p->nmethods_do(cf);
4641 }
4642 }
4643 }
4644
4645 void Threads::metadata_do(MetadataClosure* f) {
4646 ALL_JAVA_THREADS(p) {
4647 p->metadata_do(f);
4648 }
4649 }
4650
4651 class ThreadHandlesClosure : public ThreadClosure {
4652 void (*_f)(Metadata*);
4653 public:
4654 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4655 virtual void do_thread(Thread* thread) {
4656 thread->metadata_handles_do(_f);
4657 }
4658 };
4659
4660 void Threads::metadata_handles_do(void f(Metadata*)) {
4661 // Only walk the Handles in Thread.
4662 ThreadHandlesClosure handles_closure(f);
4663 threads_do(&handles_closure);
4664 }
4665
4666 // Get count Java threads that are waiting to enter the specified monitor.
4667 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4668 int count,
4669 address monitor) {
4670 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4671
4672 int i = 0;
4673 DO_JAVA_THREADS(t_list, p) {
4674 if (!p->can_call_java()) continue;
4675
4676 address pending = (address)p->current_pending_monitor();
4677 if (pending == monitor) { // found a match
4678 if (i < count) result->append(p); // save the first count matches
4679 i++;
4680 }
4681 }
4682
4683 return result;
4684 }
4685
4686
4687 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4688 address owner) {
4689 // NULL owner means not locked so we can skip the search
4690 if (owner == NULL) return NULL;
4691
4692 DO_JAVA_THREADS(t_list, p) {
4693 // first, see if owner is the address of a Java thread
4694 if (owner == (address)p) return p;
4695 }
4696
4697 // Cannot assert on lack of success here since this function may be
4698 // used by code that is trying to report useful problem information
4699 // like deadlock detection.
4700 if (UseHeavyMonitors) return NULL;
4701
4702 // If we didn't find a matching Java thread and we didn't force use of
4703 // heavyweight monitors, then the owner is the stack address of the
4704 // Lock Word in the owning Java thread's stack.
4705 //
4706 JavaThread* the_owner = NULL;
4707 DO_JAVA_THREADS(t_list, q) {
4708 if (q->is_lock_owned(owner)) {
4709 the_owner = q;
4710 break;
4711 }
4712 }
4713
4714 // cannot assert on lack of success here; see above comment
4715 return the_owner;
4716 }
4717
4718 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4719 void Threads::print_on(outputStream* st, bool print_stacks,
4720 bool internal_format, bool print_concurrent_locks,
4721 bool print_extended_info) {
4722 char buf[32];
4723 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4724
4725 st->print_cr("Full thread dump %s (%s %s):",
4726 VM_Version::vm_name(),
4727 VM_Version::vm_release(),
4728 VM_Version::vm_info_string());
4729 st->cr();
4730
4731 #if INCLUDE_SERVICES
4732 // Dump concurrent locks
4733 ConcurrentLocksDump concurrent_locks;
4734 if (print_concurrent_locks) {
4735 concurrent_locks.dump_at_safepoint();
4736 }
4737 #endif // INCLUDE_SERVICES
4738
4739 ThreadsSMRSupport::print_info_on(st);
4740 st->cr();
4741
4742 ALL_JAVA_THREADS(p) {
4743 ResourceMark rm;
4744 p->print_on(st, print_extended_info);
4745 if (print_stacks) {
4746 if (internal_format) {
4747 p->trace_stack();
4748 } else {
4749 p->print_stack_on(st);
4750 }
4751 }
4752 st->cr();
4753 #if INCLUDE_SERVICES
4754 if (print_concurrent_locks) {
4755 concurrent_locks.print_locks_on(p, st);
4756 }
4757 #endif // INCLUDE_SERVICES
4758 }
4759
4760 VMThread::vm_thread()->print_on(st);
4761 st->cr();
4762 Universe::heap()->print_gc_threads_on(st);
4763 WatcherThread* wt = WatcherThread::watcher_thread();
4764 if (wt != NULL) {
4765 wt->print_on(st);
4766 st->cr();
4767 }
4768
4769 st->flush();
4770 }
4771
4772 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4773 int buflen, bool* found_current) {
4774 if (this_thread != NULL) {
4775 bool is_current = (current == this_thread);
4776 *found_current = *found_current || is_current;
4777 st->print("%s", is_current ? "=>" : " ");
4778
4779 st->print(PTR_FORMAT, p2i(this_thread));
4780 st->print(" ");
4781 this_thread->print_on_error(st, buf, buflen);
4782 st->cr();
4783 }
4784 }
4785
4786 class PrintOnErrorClosure : public ThreadClosure {
4787 outputStream* _st;
4788 Thread* _current;
4789 char* _buf;
4790 int _buflen;
4791 bool* _found_current;
4792 public:
4793 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4794 int buflen, bool* found_current) :
4795 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4796
4797 virtual void do_thread(Thread* thread) {
4798 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4799 }
4800 };
4801
4802 // Threads::print_on_error() is called by fatal error handler. It's possible
4803 // that VM is not at safepoint and/or current thread is inside signal handler.
4804 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4805 // memory (even in resource area), it might deadlock the error handler.
4806 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4807 int buflen) {
4808 ThreadsSMRSupport::print_info_on(st);
4809 st->cr();
4810
4811 bool found_current = false;
4812 st->print_cr("Java Threads: ( => current thread )");
4813 ALL_JAVA_THREADS(thread) {
4814 print_on_error(thread, st, current, buf, buflen, &found_current);
4815 }
4816 st->cr();
4817
4818 st->print_cr("Other Threads:");
4819 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4820 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4821
4822 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4823 Universe::heap()->gc_threads_do(&print_closure);
4824
4825 if (!found_current) {
4826 st->cr();
4827 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4828 current->print_on_error(st, buf, buflen);
4829 st->cr();
4830 }
4831 st->cr();
4832
4833 st->print_cr("Threads with active compile tasks:");
4834 print_threads_compiling(st, buf, buflen);
4835 }
4836
4837 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
4838 ALL_JAVA_THREADS(thread) {
4839 if (thread->is_Compiler_thread()) {
4840 CompilerThread* ct = (CompilerThread*) thread;
4841
4842 // Keep task in local variable for NULL check.
4843 // ct->_task might be set to NULL by concurring compiler thread
4844 // because it completed the compilation. The task is never freed,
4845 // though, just returned to a free list.
4846 CompileTask* task = ct->task();
4847 if (task != NULL) {
4848 thread->print_name_on_error(st, buf, buflen);
4849 st->print(" ");
4850 task->print(st, NULL, short_form, true);
4851 }
4852 }
4853 }
4854 }
4855
4856
4857 // Internal SpinLock and Mutex
4858 // Based on ParkEvent
4859
4860 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4861 //
4862 // We employ SpinLocks _only for low-contention, fixed-length
4863 // short-duration critical sections where we're concerned
4864 // about native mutex_t or HotSpot Mutex:: latency.
4865 // The mux construct provides a spin-then-block mutual exclusion
4866 // mechanism.
4867 //
4868 // Testing has shown that contention on the ListLock guarding gFreeList
4869 // is common. If we implement ListLock as a simple SpinLock it's common
4870 // for the JVM to devolve to yielding with little progress. This is true
4871 // despite the fact that the critical sections protected by ListLock are
4872 // extremely short.
4873 //
4874 // TODO-FIXME: ListLock should be of type SpinLock.
4875 // We should make this a 1st-class type, integrated into the lock
4876 // hierarchy as leaf-locks. Critically, the SpinLock structure
4877 // should have sufficient padding to avoid false-sharing and excessive
4878 // cache-coherency traffic.
4879
4880
4881 typedef volatile int SpinLockT;
4882
4883 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4884 if (Atomic::cmpxchg(adr, 0, 1) == 0) {
4885 return; // normal fast-path return
4886 }
4887
4888 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4889 int ctr = 0;
4890 int Yields = 0;
4891 for (;;) {
4892 while (*adr != 0) {
4893 ++ctr;
4894 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4895 if (Yields > 5) {
4896 os::naked_short_sleep(1);
4897 } else {
4898 os::naked_yield();
4899 ++Yields;
4900 }
4901 } else {
4902 SpinPause();
4903 }
4904 }
4905 if (Atomic::cmpxchg(adr, 0, 1) == 0) return;
4906 }
4907 }
4908
4909 void Thread::SpinRelease(volatile int * adr) {
4910 assert(*adr != 0, "invariant");
4911 OrderAccess::fence(); // guarantee at least release consistency.
4912 // Roach-motel semantics.
4913 // It's safe if subsequent LDs and STs float "up" into the critical section,
4914 // but prior LDs and STs within the critical section can't be allowed
4915 // to reorder or float past the ST that releases the lock.
4916 // Loads and stores in the critical section - which appear in program
4917 // order before the store that releases the lock - must also appear
4918 // before the store that releases the lock in memory visibility order.
4919 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4920 // the ST of 0 into the lock-word which releases the lock, so fence
4921 // more than covers this on all platforms.
4922 *adr = 0;
4923 }
4924
4925 // muxAcquire and muxRelease:
4926 //
4927 // * muxAcquire and muxRelease support a single-word lock-word construct.
4928 // The LSB of the word is set IFF the lock is held.
4929 // The remainder of the word points to the head of a singly-linked list
4930 // of threads blocked on the lock.
4931 //
4932 // * The current implementation of muxAcquire-muxRelease uses its own
4933 // dedicated Thread._MuxEvent instance. If we're interested in
4934 // minimizing the peak number of extant ParkEvent instances then
4935 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4936 // as certain invariants were satisfied. Specifically, care would need
4937 // to be taken with regards to consuming unpark() "permits".
4938 // A safe rule of thumb is that a thread would never call muxAcquire()
4939 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4940 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4941 // consume an unpark() permit intended for monitorenter, for instance.
4942 // One way around this would be to widen the restricted-range semaphore
4943 // implemented in park(). Another alternative would be to provide
4944 // multiple instances of the PlatformEvent() for each thread. One
4945 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4946 //
4947 // * Usage:
4948 // -- Only as leaf locks
4949 // -- for short-term locking only as muxAcquire does not perform
4950 // thread state transitions.
4951 //
4952 // Alternatives:
4953 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4954 // but with parking or spin-then-park instead of pure spinning.
4955 // * Use Taura-Oyama-Yonenzawa locks.
4956 // * It's possible to construct a 1-0 lock if we encode the lockword as
4957 // (List,LockByte). Acquire will CAS the full lockword while Release
4958 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4959 // acquiring threads use timers (ParkTimed) to detect and recover from
4960 // the stranding window. Thread/Node structures must be aligned on 256-byte
4961 // boundaries by using placement-new.
4962 // * Augment MCS with advisory back-link fields maintained with CAS().
4963 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4964 // The validity of the backlinks must be ratified before we trust the value.
4965 // If the backlinks are invalid the exiting thread must back-track through the
4966 // the forward links, which are always trustworthy.
4967 // * Add a successor indication. The LockWord is currently encoded as
4968 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4969 // to provide the usual futile-wakeup optimization.
4970 // See RTStt for details.
4971 //
4972
4973
4974 const intptr_t LOCKBIT = 1;
4975
4976 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4977 intptr_t w = Atomic::cmpxchg(Lock, (intptr_t)0, LOCKBIT);
4978 if (w == 0) return;
4979 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) {
4980 return;
4981 }
4982
4983 ParkEvent * const Self = Thread::current()->_MuxEvent;
4984 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4985 for (;;) {
4986 int its = (os::is_MP() ? 100 : 0) + 1;
4987
4988 // Optional spin phase: spin-then-park strategy
4989 while (--its >= 0) {
4990 w = *Lock;
4991 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) {
4992 return;
4993 }
4994 }
4995
4996 Self->reset();
4997 Self->OnList = intptr_t(Lock);
4998 // The following fence() isn't _strictly necessary as the subsequent
4999 // CAS() both serializes execution and ratifies the fetched *Lock value.
5000 OrderAccess::fence();
5001 for (;;) {
5002 w = *Lock;
5003 if ((w & LOCKBIT) == 0) {
5004 if (Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) {
5005 Self->OnList = 0; // hygiene - allows stronger asserts
5006 return;
5007 }
5008 continue; // Interference -- *Lock changed -- Just retry
5009 }
5010 assert(w & LOCKBIT, "invariant");
5011 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
5012 if (Atomic::cmpxchg(Lock, w, intptr_t(Self)|LOCKBIT) == w) break;
5013 }
5014
5015 while (Self->OnList != 0) {
5016 Self->park();
5017 }
5018 }
5019 }
5020
5021 // Release() must extract a successor from the list and then wake that thread.
5022 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
5023 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
5024 // Release() would :
5025 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
5026 // (B) Extract a successor from the private list "in-hand"
5027 // (C) attempt to CAS() the residual back into *Lock over null.
5028 // If there were any newly arrived threads and the CAS() would fail.
5029 // In that case Release() would detach the RATs, re-merge the list in-hand
5030 // with the RATs and repeat as needed. Alternately, Release() might
5031 // detach and extract a successor, but then pass the residual list to the wakee.
5032 // The wakee would be responsible for reattaching and remerging before it
5033 // competed for the lock.
5034 //
5035 // Both "pop" and DMR are immune from ABA corruption -- there can be
5036 // multiple concurrent pushers, but only one popper or detacher.
5037 // This implementation pops from the head of the list. This is unfair,
5038 // but tends to provide excellent throughput as hot threads remain hot.
5039 // (We wake recently run threads first).
5040 //
5041 // All paths through muxRelease() will execute a CAS.
5042 // Release consistency -- We depend on the CAS in muxRelease() to provide full
5043 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
5044 // executed within the critical section are complete and globally visible before the
5045 // store (CAS) to the lock-word that releases the lock becomes globally visible.
5046 void Thread::muxRelease(volatile intptr_t * Lock) {
5047 for (;;) {
5048 const intptr_t w = Atomic::cmpxchg(Lock, LOCKBIT, (intptr_t)0);
5049 assert(w & LOCKBIT, "invariant");
5050 if (w == LOCKBIT) return;
5051 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
5052 assert(List != NULL, "invariant");
5053 assert(List->OnList == intptr_t(Lock), "invariant");
5054 ParkEvent * const nxt = List->ListNext;
5055 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5056
5057 // The following CAS() releases the lock and pops the head element.
5058 // The CAS() also ratifies the previously fetched lock-word value.
5059 if (Atomic::cmpxchg(Lock, w, intptr_t(nxt)) != w) {
5060 continue;
5061 }
5062 List->OnList = 0;
5063 OrderAccess::fence();
5064 List->unpark();
5065 return;
5066 }
5067 }
5068
5069
5070 void Threads::verify() {
5071 ALL_JAVA_THREADS(p) {
5072 p->verify();
5073 }
5074 VMThread* thread = VMThread::vm_thread();
5075 if (thread != NULL) thread->verify();
5076 }