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/flags/jvmFlagConstraintList.hpp"
70 #include "runtime/flags/jvmFlagRangeList.hpp"
71 #include "runtime/deoptimization.hpp"
72 #include "runtime/frame.inline.hpp"
73 #include "runtime/handles.inline.hpp"
74 #include "runtime/handshake.hpp"
75 #include "runtime/init.hpp"
76 #include "runtime/interfaceSupport.inline.hpp"
77 #include "runtime/java.hpp"
78 #include "runtime/javaCalls.hpp"
79 #include "runtime/jniHandles.inline.hpp"
80 #include "runtime/jniPeriodicChecker.hpp"
81 #include "runtime/memprofiler.hpp"
82 #include "runtime/mutexLocker.hpp"
83 #include "runtime/objectMonitor.hpp"
84 #include "runtime/orderAccess.hpp"
85 #include "runtime/osThread.hpp"
86 #include "runtime/prefetch.inline.hpp"
87 #include "runtime/safepoint.hpp"
88 #include "runtime/safepointMechanism.inline.hpp"
89 #include "runtime/safepointVerifiers.hpp"
90 #include "runtime/serviceThread.hpp"
91 #include "runtime/sharedRuntime.hpp"
92 #include "runtime/statSampler.hpp"
93 #include "runtime/stubRoutines.hpp"
94 #include "runtime/sweeper.hpp"
95 #include "runtime/task.hpp"
96 #include "runtime/thread.inline.hpp"
97 #include "runtime/threadCritical.hpp"
98 #include "runtime/threadSMR.inline.hpp"
99 #include "runtime/threadStatisticalInfo.hpp"
100 #include "runtime/timer.hpp"
101 #include "runtime/timerTrace.hpp"
102 #include "runtime/vframe.inline.hpp"
103 #include "runtime/vframeArray.hpp"
104 #include "runtime/vframe_hp.hpp"
105 #include "runtime/vmThread.hpp"
106 #include "runtime/vmOperations.hpp"
107 #include "runtime/vm_version.hpp"
108 #include "services/attachListener.hpp"
109 #include "services/management.hpp"
110 #include "services/memTracker.hpp"
111 #include "services/threadService.hpp"
112 #include "utilities/align.hpp"
113 #include "utilities/copy.hpp"
114 #include "utilities/defaultStream.hpp"
115 #include "utilities/dtrace.hpp"
116 #include "utilities/events.hpp"
117 #include "utilities/macros.hpp"
118 #include "utilities/preserveException.hpp"
119 #include "utilities/singleWriterSynchronizer.hpp"
120 #include "utilities/vmError.hpp"
121 #if INCLUDE_JVMCI
122 #include "jvmci/jvmci.hpp"
123 #include "jvmci/jvmciEnv.hpp"
124 #endif
125 #ifdef COMPILER1
126 #include "c1/c1_Compiler.hpp"
127 #endif
128 #ifdef COMPILER2
129 #include "opto/c2compiler.hpp"
130 #include "opto/idealGraphPrinter.hpp"
131 #endif
132 #if INCLUDE_RTM_OPT
133 #include "runtime/rtmLocking.hpp"
134 #endif
135 #if INCLUDE_JFR
136 #include "jfr/jfr.hpp"
137 #endif
138
139 // Initialization after module runtime initialization
140 void universe_post_module_init(); // must happen after call_initPhase2
141
142 #ifdef DTRACE_ENABLED
143
144 // Only bother with this argument setup if dtrace is available
145
146 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
147 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
148
149 #define DTRACE_THREAD_PROBE(probe, javathread) \
150 { \
151 ResourceMark rm(this); \
152 int len = 0; \
153 const char* name = (javathread)->get_thread_name(); \
154 len = strlen(name); \
155 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
156 (char *) name, len, \
157 java_lang_Thread::thread_id((javathread)->threadObj()), \
158 (uintptr_t) (javathread)->osthread()->thread_id(), \
159 java_lang_Thread::is_daemon((javathread)->threadObj())); \
160 }
161
162 #else // ndef DTRACE_ENABLED
163
164 #define DTRACE_THREAD_PROBE(probe, javathread)
165
166 #endif // ndef DTRACE_ENABLED
167
168 #ifndef USE_LIBRARY_BASED_TLS_ONLY
169 // Current thread is maintained as a thread-local variable
170 THREAD_LOCAL Thread* Thread::_thr_current = NULL;
171 #endif
172
173 // ======= Thread ========
174 // Support for forcing alignment of thread objects for biased locking
175 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
176 if (UseBiasedLocking) {
177 const size_t alignment = markWord::biased_lock_alignment;
178 size_t aligned_size = size + (alignment - sizeof(intptr_t));
179 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
180 : AllocateHeap(aligned_size, flags, CURRENT_PC,
181 AllocFailStrategy::RETURN_NULL);
182 void* aligned_addr = align_up(real_malloc_addr, alignment);
183 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
184 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
185 "JavaThread alignment code overflowed allocated storage");
186 if (aligned_addr != real_malloc_addr) {
187 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
188 p2i(real_malloc_addr),
189 p2i(aligned_addr));
190 }
191 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
192 return aligned_addr;
193 } else {
194 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
195 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
196 }
197 }
198
199 void Thread::operator delete(void* p) {
200 if (UseBiasedLocking) {
201 FreeHeap(((Thread*) p)->_real_malloc_address);
202 } else {
203 FreeHeap(p);
204 }
205 }
206
207 void JavaThread::smr_delete() {
208 if (_on_thread_list) {
209 ThreadsSMRSupport::smr_delete(this);
210 } else {
211 delete this;
212 }
213 }
214
215 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
216 // JavaThread
217
218 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
219
220 Thread::Thread() {
221
222 DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
223
224 // stack and get_thread
225 set_stack_base(NULL);
226 set_stack_size(0);
227 set_lgrp_id(-1);
228 DEBUG_ONLY(clear_suspendible_thread();)
229
230 // allocated data structures
231 set_osthread(NULL);
232 set_resource_area(new (mtThread)ResourceArea());
233 DEBUG_ONLY(_current_resource_mark = NULL;)
234 set_handle_area(new (mtThread) HandleArea(NULL));
235 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
236 set_active_handles(NULL);
237 set_free_handle_block(NULL);
238 set_last_handle_mark(NULL);
239 DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
240
241 // Initial value of zero ==> never claimed.
242 _threads_do_token = 0;
243 _threads_hazard_ptr = NULL;
244 _threads_list_ptr = NULL;
245 _nested_threads_hazard_ptr_cnt = 0;
246 _rcu_counter = 0;
247
248 // the handle mark links itself to last_handle_mark
249 new HandleMark(this);
250
251 // plain initialization
252 debug_only(_owned_locks = NULL;)
253 NOT_PRODUCT(_no_safepoint_count = 0;)
254 NOT_PRODUCT(_skip_gcalot = false;)
255 _jvmti_env_iteration_count = 0;
256 set_allocated_bytes(0);
257 _vm_operation_started_count = 0;
258 _vm_operation_completed_count = 0;
259 _current_pending_monitor = NULL;
260 _current_pending_monitor_is_from_java = true;
261 _current_waiting_monitor = NULL;
262 _current_pending_raw_monitor = NULL;
263 _num_nested_signal = 0;
264 om_free_list = NULL;
265 om_free_count = 0;
266 om_free_provision = 32;
267 om_in_use_list = NULL;
268 om_in_use_count = 0;
269
270 #ifdef ASSERT
271 _visited_for_critical_count = false;
272 #endif
273
274 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
275 Monitor::_safepoint_check_sometimes);
276 _suspend_flags = 0;
277
278 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
279 _hashStateX = os::random();
280 _hashStateY = 842502087;
281 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
282 _hashStateW = 273326509;
283
284 _OnTrap = 0;
285 _Stalled = 0;
286 _TypeTag = 0x2BAD;
287
288 // Many of the following fields are effectively final - immutable
289 // Note that nascent threads can't use the Native Monitor-Mutex
290 // construct until the _MutexEvent is initialized ...
291 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
292 // we might instead use a stack of ParkEvents that we could provision on-demand.
293 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
294 // and ::Release()
295 _ParkEvent = ParkEvent::Allocate(this);
296 _MuxEvent = ParkEvent::Allocate(this);
297
298 #ifdef CHECK_UNHANDLED_OOPS
299 if (CheckUnhandledOops) {
300 _unhandled_oops = new UnhandledOops(this);
301 }
302 #endif // CHECK_UNHANDLED_OOPS
303 #ifdef ASSERT
304 if (UseBiasedLocking) {
305 assert(is_aligned(this, markWord::biased_lock_alignment), "forced alignment of thread object failed");
306 assert(this == _real_malloc_address ||
307 this == align_up(_real_malloc_address, markWord::biased_lock_alignment),
308 "bug in forced alignment of thread objects");
309 }
310 #endif // ASSERT
311
312 // Notify the barrier set that a thread is being created. The initial
313 // thread is created before the barrier set is available. The call to
314 // BarrierSet::on_thread_create() for this thread is therefore deferred
315 // to BarrierSet::set_barrier_set().
316 BarrierSet* const barrier_set = BarrierSet::barrier_set();
317 if (barrier_set != NULL) {
318 barrier_set->on_thread_create(this);
319 } else {
320 // Only the main thread should be created before the barrier set
321 // and that happens just before Thread::current is set. No other thread
322 // can attach as the VM is not created yet, so they can't execute this code.
323 // If the main thread creates other threads before the barrier set that is an error.
324 assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
325 }
326 }
327
328 void Thread::initialize_thread_current() {
329 #ifndef USE_LIBRARY_BASED_TLS_ONLY
330 assert(_thr_current == NULL, "Thread::current already initialized");
331 _thr_current = this;
332 #endif
333 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
334 ThreadLocalStorage::set_thread(this);
335 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
336 }
337
338 void Thread::clear_thread_current() {
339 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
340 #ifndef USE_LIBRARY_BASED_TLS_ONLY
341 _thr_current = NULL;
342 #endif
343 ThreadLocalStorage::set_thread(NULL);
344 }
345
346 void Thread::record_stack_base_and_size() {
347 // Note: at this point, Thread object is not yet initialized. Do not rely on
348 // any members being initialized. Do not rely on Thread::current() being set.
349 // If possible, refrain from doing anything which may crash or assert since
350 // quite probably those crash dumps will be useless.
351 set_stack_base(os::current_stack_base());
352 set_stack_size(os::current_stack_size());
353
354 #ifdef SOLARIS
355 if (os::is_primordial_thread()) {
356 os::Solaris::correct_stack_boundaries_for_primordial_thread(this);
357 }
358 #endif
359
360 // Set stack limits after thread is initialized.
361 if (is_Java_thread()) {
362 ((JavaThread*) this)->set_stack_overflow_limit();
363 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
364 }
365 }
366
367 #if INCLUDE_NMT
368 void Thread::register_thread_stack_with_NMT() {
369 MemTracker::record_thread_stack(stack_end(), stack_size());
370 }
371 #endif // INCLUDE_NMT
372
373 void Thread::call_run() {
374 DEBUG_ONLY(_run_state = CALL_RUN;)
375
376 // At this point, Thread object should be fully initialized and
377 // Thread::current() should be set.
378
379 assert(Thread::current_or_null() != NULL, "current thread is unset");
380 assert(Thread::current_or_null() == this, "current thread is wrong");
381
382 // Perform common initialization actions
383
384 register_thread_stack_with_NMT();
385
386 JFR_ONLY(Jfr::on_thread_start(this);)
387
388 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
389 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
390 os::current_thread_id(), p2i(stack_end()),
391 p2i(stack_base()), stack_size()/1024);
392
393 // Perform <ChildClass> initialization actions
394 DEBUG_ONLY(_run_state = PRE_RUN;)
395 this->pre_run();
396
397 // Invoke <ChildClass>::run()
398 DEBUG_ONLY(_run_state = RUN;)
399 this->run();
400 // Returned from <ChildClass>::run(). Thread finished.
401
402 // Perform common tear-down actions
403
404 assert(Thread::current_or_null() != NULL, "current thread is unset");
405 assert(Thread::current_or_null() == this, "current thread is wrong");
406
407 // Perform <ChildClass> tear-down actions
408 DEBUG_ONLY(_run_state = POST_RUN;)
409 this->post_run();
410
411 // Note: at this point the thread object may already have deleted itself,
412 // so from here on do not dereference *this*. Not all thread types currently
413 // delete themselves when they terminate. But no thread should ever be deleted
414 // asynchronously with respect to its termination - that is what _run_state can
415 // be used to check.
416
417 assert(Thread::current_or_null() == NULL, "current thread still present");
418 }
419
420 Thread::~Thread() {
421
422 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
423 // get started due to errors etc. Any active thread should at least reach post_run
424 // before it is deleted (usually in post_run()).
425 assert(_run_state == PRE_CALL_RUN ||
426 _run_state == POST_RUN, "Active Thread deleted before post_run(): "
427 "_run_state=%d", (int)_run_state);
428
429 // Notify the barrier set that a thread is being destroyed. Note that a barrier
430 // set might not be available if we encountered errors during bootstrapping.
431 BarrierSet* const barrier_set = BarrierSet::barrier_set();
432 if (barrier_set != NULL) {
433 barrier_set->on_thread_destroy(this);
434 }
435
436 // stack_base can be NULL if the thread is never started or exited before
437 // record_stack_base_and_size called. Although, we would like to ensure
438 // that all started threads do call record_stack_base_and_size(), there is
439 // not proper way to enforce that.
440 #if INCLUDE_NMT
441 if (_stack_base != NULL) {
442 MemTracker::release_thread_stack(stack_end(), stack_size());
443 #ifdef ASSERT
444 set_stack_base(NULL);
445 #endif
446 }
447 #endif // INCLUDE_NMT
448
449 // deallocate data structures
450 delete resource_area();
451 // since the handle marks are using the handle area, we have to deallocated the root
452 // handle mark before deallocating the thread's handle area,
453 assert(last_handle_mark() != NULL, "check we have an element");
454 delete last_handle_mark();
455 assert(last_handle_mark() == NULL, "check we have reached the end");
456
457 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
458 // We NULL out the fields for good hygiene.
459 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
460 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
461
462 delete handle_area();
463 delete metadata_handles();
464
465 // SR_handler uses this as a termination indicator -
466 // needs to happen before os::free_thread()
467 delete _SR_lock;
468 _SR_lock = NULL;
469
470 // osthread() can be NULL, if creation of thread failed.
471 if (osthread() != NULL) os::free_thread(osthread());
472
473 // Clear Thread::current if thread is deleting itself and it has not
474 // already been done. This must be done before the memory is deallocated.
475 // Needed to ensure JNI correctly detects non-attached threads.
476 if (this == Thread::current_or_null()) {
477 Thread::clear_thread_current();
478 }
479
480 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
481 }
482
483 #ifdef ASSERT
484 // A JavaThread is considered "dangling" if it is not the current
485 // thread, has been added the Threads list, the system is not at a
486 // safepoint and the Thread is not "protected".
487 //
488 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
489 assert(!thread->is_Java_thread() || Thread::current() == thread ||
490 !((JavaThread *) thread)->on_thread_list() ||
491 SafepointSynchronize::is_at_safepoint() ||
492 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
493 "possibility of dangling Thread pointer");
494 }
495 #endif
496
497 ThreadPriority Thread::get_priority(const Thread* const thread) {
498 ThreadPriority priority;
499 // Can return an error!
500 (void)os::get_priority(thread, priority);
501 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
502 return priority;
503 }
504
505 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
506 debug_only(check_for_dangling_thread_pointer(thread);)
507 // Can return an error!
508 (void)os::set_priority(thread, priority);
509 }
510
511
512 void Thread::start(Thread* thread) {
513 // Start is different from resume in that its safety is guaranteed by context or
514 // being called from a Java method synchronized on the Thread object.
515 if (!DisableStartThread) {
516 if (thread->is_Java_thread()) {
517 // Initialize the thread state to RUNNABLE before starting this thread.
518 // Can not set it after the thread started because we do not know the
519 // exact thread state at that time. It could be in MONITOR_WAIT or
520 // in SLEEPING or some other state.
521 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
522 java_lang_Thread::RUNNABLE);
523 }
524 os::start_thread(thread);
525 }
526 }
527
528 class InstallAsyncExceptionClosure : public HandshakeClosure {
529 Handle _throwable; // The Throwable thrown at the target Thread
530 public:
531 InstallAsyncExceptionClosure(Handle throwable) : HandshakeClosure("InstallAsyncException"), _throwable(throwable) {}
532
533 void do_thread(Thread* thr) {
534 JavaThread* target = (JavaThread*)thr;
535 // Note that this now allows multiple ThreadDeath exceptions to be
536 // thrown at a thread.
537 // The target thread has run and has not exited yet.
538 target->send_thread_stop(_throwable());
539 }
540 };
541
542 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
543 Handle throwable(Thread::current(), java_throwable);
544 JavaThread* target = java_lang_Thread::thread(java_thread);
545 InstallAsyncExceptionClosure vm_stop(throwable);
546 Handshake::execute(&vm_stop, target);
547 }
548
549
550 // Check if an external suspend request has completed (or has been
551 // cancelled). Returns true if the thread is externally suspended and
552 // false otherwise.
553 //
554 // The bits parameter returns information about the code path through
555 // the routine. Useful for debugging:
556 //
557 // set in is_ext_suspend_completed():
558 // 0x00000001 - routine was entered
559 // 0x00000010 - routine return false at end
560 // 0x00000100 - thread exited (return false)
561 // 0x00000200 - suspend request cancelled (return false)
562 // 0x00000400 - thread suspended (return true)
563 // 0x00001000 - thread is in a suspend equivalent state (return true)
564 // 0x00002000 - thread is native and walkable (return true)
565 // 0x00004000 - thread is native_trans and walkable (needed retry)
566 //
567 // set in wait_for_ext_suspend_completion():
568 // 0x00010000 - routine was entered
569 // 0x00020000 - suspend request cancelled before loop (return false)
570 // 0x00040000 - thread suspended before loop (return true)
571 // 0x00080000 - suspend request cancelled in loop (return false)
572 // 0x00100000 - thread suspended in loop (return true)
573 // 0x00200000 - suspend not completed during retry loop (return false)
574
575 // Helper class for tracing suspend wait debug bits.
576 //
577 // 0x00000100 indicates that the target thread exited before it could
578 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
579 // 0x00080000 each indicate a cancelled suspend request so they don't
580 // count as wait failures either.
581 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
582
583 class TraceSuspendDebugBits : public StackObj {
584 private:
585 JavaThread * jt;
586 bool is_wait;
587 bool called_by_wait; // meaningful when !is_wait
588 uint32_t * bits;
589
590 public:
591 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
592 uint32_t *_bits) {
593 jt = _jt;
594 is_wait = _is_wait;
595 called_by_wait = _called_by_wait;
596 bits = _bits;
597 }
598
599 ~TraceSuspendDebugBits() {
600 if (!is_wait) {
601 #if 1
602 // By default, don't trace bits for is_ext_suspend_completed() calls.
603 // That trace is very chatty.
604 return;
605 #else
606 if (!called_by_wait) {
607 // If tracing for is_ext_suspend_completed() is enabled, then only
608 // trace calls to it from wait_for_ext_suspend_completion()
609 return;
610 }
611 #endif
612 }
613
614 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
615 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
616 MutexLocker ml(Threads_lock); // needed for get_thread_name()
617 ResourceMark rm;
618
619 tty->print_cr(
620 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
621 jt->get_thread_name(), *bits);
622
623 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
624 }
625 }
626 }
627 };
628 #undef DEBUG_FALSE_BITS
629
630
631 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
632 uint32_t *bits) {
633 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
634
635 bool did_trans_retry = false; // only do thread_in_native_trans retry once
636 bool do_trans_retry; // flag to force the retry
637
638 *bits |= 0x00000001;
639
640 do {
641 do_trans_retry = false;
642
643 if (is_exiting()) {
644 // Thread is in the process of exiting. This is always checked
645 // first to reduce the risk of dereferencing a freed JavaThread.
646 *bits |= 0x00000100;
647 return false;
648 }
649
650 if (!is_external_suspend()) {
651 // Suspend request is cancelled. This is always checked before
652 // is_ext_suspended() to reduce the risk of a rogue resume
653 // confusing the thread that made the suspend request.
654 *bits |= 0x00000200;
655 return false;
656 }
657
658 if (is_ext_suspended()) {
659 // thread is suspended
660 *bits |= 0x00000400;
661 return true;
662 }
663
664 // Now that we no longer do hard suspends of threads running
665 // native code, the target thread can be changing thread state
666 // while we are in this routine:
667 //
668 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
669 //
670 // We save a copy of the thread state as observed at this moment
671 // and make our decision about suspend completeness based on the
672 // copy. This closes the race where the thread state is seen as
673 // _thread_in_native_trans in the if-thread_blocked check, but is
674 // seen as _thread_blocked in if-thread_in_native_trans check.
675 JavaThreadState save_state = thread_state();
676
677 if (save_state == _thread_blocked && is_suspend_equivalent()) {
678 // If the thread's state is _thread_blocked and this blocking
679 // condition is known to be equivalent to a suspend, then we can
680 // consider the thread to be externally suspended. This means that
681 // the code that sets _thread_blocked has been modified to do
682 // self-suspension if the blocking condition releases. We also
683 // used to check for CONDVAR_WAIT here, but that is now covered by
684 // the _thread_blocked with self-suspension check.
685 //
686 // Return true since we wouldn't be here unless there was still an
687 // external suspend request.
688 *bits |= 0x00001000;
689 return true;
690 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
691 // Threads running native code will self-suspend on native==>VM/Java
692 // transitions. If its stack is walkable (should always be the case
693 // unless this function is called before the actual java_suspend()
694 // call), then the wait is done.
695 *bits |= 0x00002000;
696 return true;
697 } else if (!called_by_wait && !did_trans_retry &&
698 save_state == _thread_in_native_trans &&
699 frame_anchor()->walkable()) {
700 // The thread is transitioning from thread_in_native to another
701 // thread state. check_safepoint_and_suspend_for_native_trans()
702 // will force the thread to self-suspend. If it hasn't gotten
703 // there yet we may have caught the thread in-between the native
704 // code check above and the self-suspend. Lucky us. If we were
705 // called by wait_for_ext_suspend_completion(), then it
706 // will be doing the retries so we don't have to.
707 //
708 // Since we use the saved thread state in the if-statement above,
709 // there is a chance that the thread has already transitioned to
710 // _thread_blocked by the time we get here. In that case, we will
711 // make a single unnecessary pass through the logic below. This
712 // doesn't hurt anything since we still do the trans retry.
713
714 *bits |= 0x00004000;
715
716 // Once the thread leaves thread_in_native_trans for another
717 // thread state, we break out of this retry loop. We shouldn't
718 // need this flag to prevent us from getting back here, but
719 // sometimes paranoia is good.
720 did_trans_retry = true;
721
722 // We wait for the thread to transition to a more usable state.
723 for (int i = 1; i <= SuspendRetryCount; i++) {
724 // We used to do an "os::yield_all(i)" call here with the intention
725 // that yielding would increase on each retry. However, the parameter
726 // is ignored on Linux which means the yield didn't scale up. Waiting
727 // on the SR_lock below provides a much more predictable scale up for
728 // the delay. It also provides a simple/direct point to check for any
729 // safepoint requests from the VMThread
730
731 // temporarily drops SR_lock while doing wait with safepoint check
732 // (if we're a JavaThread - the WatcherThread can also call this)
733 // and increase delay with each retry
734 if (Thread::current()->is_Java_thread()) {
735 SR_lock()->wait(i * delay);
736 } else {
737 SR_lock()->wait_without_safepoint_check(i * delay);
738 }
739
740 // check the actual thread state instead of what we saved above
741 if (thread_state() != _thread_in_native_trans) {
742 // the thread has transitioned to another thread state so
743 // try all the checks (except this one) one more time.
744 do_trans_retry = true;
745 break;
746 }
747 } // end retry loop
748
749
750 }
751 } while (do_trans_retry);
752
753 *bits |= 0x00000010;
754 return false;
755 }
756
757 // Wait for an external suspend request to complete (or be cancelled).
758 // Returns true if the thread is externally suspended and false otherwise.
759 //
760 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
761 uint32_t *bits) {
762 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
763 false /* !called_by_wait */, bits);
764
765 // local flag copies to minimize SR_lock hold time
766 bool is_suspended;
767 bool pending;
768 uint32_t reset_bits;
769
770 // set a marker so is_ext_suspend_completed() knows we are the caller
771 *bits |= 0x00010000;
772
773 // We use reset_bits to reinitialize the bits value at the top of
774 // each retry loop. This allows the caller to make use of any
775 // unused bits for their own marking purposes.
776 reset_bits = *bits;
777
778 {
779 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
780 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
781 delay, bits);
782 pending = is_external_suspend();
783 }
784 // must release SR_lock to allow suspension to complete
785
786 if (!pending) {
787 // A cancelled suspend request is the only false return from
788 // is_ext_suspend_completed() that keeps us from entering the
789 // retry loop.
790 *bits |= 0x00020000;
791 return false;
792 }
793
794 if (is_suspended) {
795 *bits |= 0x00040000;
796 return true;
797 }
798
799 for (int i = 1; i <= retries; i++) {
800 *bits = reset_bits; // reinit to only track last retry
801
802 // We used to do an "os::yield_all(i)" call here with the intention
803 // that yielding would increase on each retry. However, the parameter
804 // is ignored on Linux which means the yield didn't scale up. Waiting
805 // on the SR_lock below provides a much more predictable scale up for
806 // the delay. It also provides a simple/direct point to check for any
807 // safepoint requests from the VMThread
808
809 {
810 Thread* t = Thread::current();
811 MonitorLocker ml(SR_lock(),
812 t->is_Java_thread() ? Mutex::_safepoint_check_flag : Mutex::_no_safepoint_check_flag);
813 // wait with safepoint check (if we're a JavaThread - the WatcherThread
814 // can also call this) and increase delay with each retry
815 ml.wait(i * delay);
816
817 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
818 delay, bits);
819
820 // It is possible for the external suspend request to be cancelled
821 // (by a resume) before the actual suspend operation is completed.
822 // Refresh our local copy to see if we still need to wait.
823 pending = is_external_suspend();
824 }
825
826 if (!pending) {
827 // A cancelled suspend request is the only false return from
828 // is_ext_suspend_completed() that keeps us from staying in the
829 // retry loop.
830 *bits |= 0x00080000;
831 return false;
832 }
833
834 if (is_suspended) {
835 *bits |= 0x00100000;
836 return true;
837 }
838 } // end retry loop
839
840 // thread did not suspend after all our retries
841 *bits |= 0x00200000;
842 return false;
843 }
844
845 // Called from API entry points which perform stack walking. If the
846 // associated JavaThread is the current thread, then wait_for_suspend
847 // is not used. Otherwise, it determines if we should wait for the
848 // "other" thread to complete external suspension. (NOTE: in future
849 // releases the suspension mechanism should be reimplemented so this
850 // is not necessary.)
851 //
852 bool
853 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
854 if (this != JavaThread::current()) {
855 // "other" threads require special handling.
856 if (wait_for_suspend) {
857 // We are allowed to wait for the external suspend to complete
858 // so give the other thread a chance to get suspended.
859 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
860 SuspendRetryDelay, bits)) {
861 // Didn't make it so let the caller know.
862 return false;
863 }
864 }
865 // We aren't allowed to wait for the external suspend to complete
866 // so if the other thread isn't externally suspended we need to
867 // let the caller know.
868 else if (!is_ext_suspend_completed_with_lock(bits)) {
869 return false;
870 }
871 }
872
873 return true;
874 }
875
876 // GC Support
877 bool Thread::claim_par_threads_do(uintx claim_token) {
878 uintx token = _threads_do_token;
879 if (token != claim_token) {
880 uintx res = Atomic::cmpxchg(&_threads_do_token, token, claim_token);
881 if (res == token) {
882 return true;
883 }
884 guarantee(res == claim_token, "invariant");
885 }
886 return false;
887 }
888
889 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
890 active_handles()->oops_do(f);
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 if (SafepointMechanism::uses_thread_local_poll()) {
1701 SafepointMechanism::initialize_header(this);
1702 }
1703
1704 _class_to_be_initialized = NULL;
1705
1706 pd_initialize();
1707 }
1708
1709 JavaThread::JavaThread(bool is_attaching_via_jni) :
1710 Thread() {
1711 initialize();
1712 if (is_attaching_via_jni) {
1713 _jni_attach_state = _attaching_via_jni;
1714 } else {
1715 _jni_attach_state = _not_attaching_via_jni;
1716 }
1717 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1718 }
1719
1720
1721 // interrupt support
1722
1723 void JavaThread::interrupt() {
1724 debug_only(check_for_dangling_thread_pointer(this);)
1725
1726 // For Windows _interrupt_event
1727 osthread()->set_interrupted(true);
1728
1729 // For Thread.sleep
1730 _SleepEvent->unpark();
1731
1732 // For JSR166 LockSupport.park
1733 parker()->unpark();
1734
1735 // For ObjectMonitor and JvmtiRawMonitor
1736 _ParkEvent->unpark();
1737 }
1738
1739
1740 bool JavaThread::is_interrupted(bool clear_interrupted) {
1741 debug_only(check_for_dangling_thread_pointer(this);)
1742
1743 if (threadObj() == NULL) {
1744 // If there is no j.l.Thread then it is impossible to have
1745 // been interrupted. We can find NULL during VM initialization
1746 // or when a JNI thread is still in the process of attaching.
1747 // In such cases this must be the current thread.
1748 assert(this == Thread::current(), "invariant");
1749 return false;
1750 }
1751
1752 bool interrupted = java_lang_Thread::interrupted(threadObj());
1753
1754 // NOTE that since there is no "lock" around the interrupt and
1755 // is_interrupted operations, there is the possibility that the
1756 // interrupted flag will be "false" but that the
1757 // low-level events will be in the signaled state. This is
1758 // intentional. The effect of this is that Object.wait() and
1759 // LockSupport.park() will appear to have a spurious wakeup, which
1760 // is allowed and not harmful, and the possibility is so rare that
1761 // it is not worth the added complexity to add yet another lock.
1762 // For the sleep event an explicit reset is performed on entry
1763 // to JavaThread::sleep, so there is no early return. It has also been
1764 // recommended not to put the interrupted flag into the "event"
1765 // structure because it hides the issue.
1766 // Also, because there is no lock, we must only clear the interrupt
1767 // state if we are going to report that we were interrupted; otherwise
1768 // an interrupt that happens just after we read the field would be lost.
1769 if (interrupted && clear_interrupted) {
1770 assert(this == Thread::current(), "only the current thread can clear");
1771 java_lang_Thread::set_interrupted(threadObj(), false);
1772 osthread()->set_interrupted(false);
1773 }
1774
1775 return interrupted;
1776 }
1777
1778 bool JavaThread::reguard_stack(address cur_sp) {
1779 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1780 && _stack_guard_state != stack_guard_reserved_disabled) {
1781 return true; // Stack already guarded or guard pages not needed.
1782 }
1783
1784 if (register_stack_overflow()) {
1785 // For those architectures which have separate register and
1786 // memory stacks, we must check the register stack to see if
1787 // it has overflowed.
1788 return false;
1789 }
1790
1791 // Java code never executes within the yellow zone: the latter is only
1792 // there to provoke an exception during stack banging. If java code
1793 // is executing there, either StackShadowPages should be larger, or
1794 // some exception code in c1, c2 or the interpreter isn't unwinding
1795 // when it should.
1796 guarantee(cur_sp > stack_reserved_zone_base(),
1797 "not enough space to reguard - increase StackShadowPages");
1798 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1799 enable_stack_yellow_reserved_zone();
1800 if (reserved_stack_activation() != stack_base()) {
1801 set_reserved_stack_activation(stack_base());
1802 }
1803 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1804 set_reserved_stack_activation(stack_base());
1805 enable_stack_reserved_zone();
1806 }
1807 return true;
1808 }
1809
1810 bool JavaThread::reguard_stack(void) {
1811 return reguard_stack(os::current_stack_pointer());
1812 }
1813
1814 void JavaThread::block_if_vm_exited() {
1815 if (_terminated == _vm_exited) {
1816 // _vm_exited is set at safepoint, and Threads_lock is never released
1817 // we will block here forever.
1818 // Here we can be doing a jump from a safe state to an unsafe state without
1819 // proper transition, but it happens after the final safepoint has begun.
1820 set_thread_state(_thread_in_vm);
1821 Threads_lock->lock();
1822 ShouldNotReachHere();
1823 }
1824 }
1825
1826
1827 // Remove this ifdef when C1 is ported to the compiler interface.
1828 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1829 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1830
1831 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1832 Thread() {
1833 initialize();
1834 _jni_attach_state = _not_attaching_via_jni;
1835 set_entry_point(entry_point);
1836 // Create the native thread itself.
1837 // %note runtime_23
1838 os::ThreadType thr_type = os::java_thread;
1839 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1840 os::java_thread;
1841 os::create_thread(this, thr_type, stack_sz);
1842 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1843 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1844 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1845 // the exception consists of creating the exception object & initializing it, initialization
1846 // will leave the VM via a JavaCall and then all locks must be unlocked).
1847 //
1848 // The thread is still suspended when we reach here. Thread must be explicit started
1849 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1850 // by calling Threads:add. The reason why this is not done here, is because the thread
1851 // object must be fully initialized (take a look at JVM_Start)
1852 }
1853
1854 JavaThread::~JavaThread() {
1855
1856 // JSR166 -- return the parker to the free list
1857 Parker::Release(_parker);
1858 _parker = NULL;
1859
1860 // Return the sleep event to the free list
1861 ParkEvent::Release(_SleepEvent);
1862 _SleepEvent = NULL;
1863
1864 // Free any remaining previous UnrollBlock
1865 vframeArray* old_array = vframe_array_last();
1866
1867 if (old_array != NULL) {
1868 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1869 old_array->set_unroll_block(NULL);
1870 delete old_info;
1871 delete old_array;
1872 }
1873
1874 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1875 if (deferred != NULL) {
1876 // This can only happen if thread is destroyed before deoptimization occurs.
1877 assert(deferred->length() != 0, "empty array!");
1878 do {
1879 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1880 deferred->remove_at(0);
1881 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1882 delete dlv;
1883 } while (deferred->length() != 0);
1884 delete deferred;
1885 }
1886
1887 // All Java related clean up happens in exit
1888 ThreadSafepointState::destroy(this);
1889 if (_thread_stat != NULL) delete _thread_stat;
1890
1891 #if INCLUDE_JVMCI
1892 if (JVMCICounterSize > 0) {
1893 if (jvmci_counters_include(this)) {
1894 for (int i = 0; i < JVMCICounterSize; i++) {
1895 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1896 }
1897 }
1898 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1899 }
1900 #endif // INCLUDE_JVMCI
1901 }
1902
1903
1904 // First JavaThread specific code executed by a new Java thread.
1905 void JavaThread::pre_run() {
1906 // empty - see comments in run()
1907 }
1908
1909 // The main routine called by a new Java thread. This isn't overridden
1910 // by subclasses, instead different subclasses define a different "entry_point"
1911 // which defines the actual logic for that kind of thread.
1912 void JavaThread::run() {
1913 // initialize thread-local alloc buffer related fields
1914 this->initialize_tlab();
1915
1916 // Used to test validity of stack trace backs.
1917 // This can't be moved into pre_run() else we invalidate
1918 // the requirement that thread_main_inner is lower on
1919 // the stack. Consequently all the initialization logic
1920 // stays here in run() rather than pre_run().
1921 this->record_base_of_stack_pointer();
1922
1923 this->create_stack_guard_pages();
1924
1925 this->cache_global_variables();
1926
1927 // Thread is now sufficiently initialized to be handled by the safepoint code as being
1928 // in the VM. Change thread state from _thread_new to _thread_in_vm
1929 ThreadStateTransition::transition(this, _thread_new, _thread_in_vm);
1930 // Before a thread is on the threads list it is always safe, so after leaving the
1931 // _thread_new we should emit a instruction barrier. The distance to modified code
1932 // from here is probably far enough, but this is consistent and safe.
1933 OrderAccess::cross_modify_fence();
1934
1935 assert(JavaThread::current() == this, "sanity check");
1936 assert(!Thread::current()->owns_locks(), "sanity check");
1937
1938 DTRACE_THREAD_PROBE(start, this);
1939
1940 // This operation might block. We call that after all safepoint checks for a new thread has
1941 // been completed.
1942 this->set_active_handles(JNIHandleBlock::allocate_block());
1943
1944 if (JvmtiExport::should_post_thread_life()) {
1945 JvmtiExport::post_thread_start(this);
1946
1947 }
1948
1949 // We call another function to do the rest so we are sure that the stack addresses used
1950 // from there will be lower than the stack base just computed.
1951 thread_main_inner();
1952 }
1953
1954 void JavaThread::thread_main_inner() {
1955 assert(JavaThread::current() == this, "sanity check");
1956 assert(this->threadObj() != NULL, "just checking");
1957
1958 // Execute thread entry point unless this thread has a pending exception
1959 // or has been stopped before starting.
1960 // Note: Due to JVM_StopThread we can have pending exceptions already!
1961 if (!this->has_pending_exception() &&
1962 !java_lang_Thread::is_stillborn(this->threadObj())) {
1963 {
1964 ResourceMark rm(this);
1965 this->set_native_thread_name(this->get_thread_name());
1966 }
1967 HandleMark hm(this);
1968 this->entry_point()(this, this);
1969 }
1970
1971 DTRACE_THREAD_PROBE(stop, this);
1972
1973 // Cleanup is handled in post_run()
1974 }
1975
1976 // Shared teardown for all JavaThreads
1977 void JavaThread::post_run() {
1978 this->exit(false);
1979 // Defer deletion to here to ensure 'this' is still referenceable in call_run
1980 // for any shared tear-down.
1981 this->smr_delete();
1982 }
1983
1984 static void ensure_join(JavaThread* thread) {
1985 // We do not need to grab the Threads_lock, since we are operating on ourself.
1986 Handle threadObj(thread, thread->threadObj());
1987 assert(threadObj.not_null(), "java thread object must exist");
1988 ObjectLocker lock(threadObj, thread);
1989 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1990 thread->clear_pending_exception();
1991 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1992 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1993 // Clear the native thread instance - this makes isAlive return false and allows the join()
1994 // to complete once we've done the notify_all below
1995 java_lang_Thread::set_thread(threadObj(), NULL);
1996 lock.notify_all(thread);
1997 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1998 thread->clear_pending_exception();
1999 }
2000
2001 static bool is_daemon(oop threadObj) {
2002 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
2003 }
2004
2005 // For any new cleanup additions, please check to see if they need to be applied to
2006 // cleanup_failed_attach_current_thread as well.
2007 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
2008 assert(this == JavaThread::current(), "thread consistency check");
2009
2010 elapsedTimer _timer_exit_phase1;
2011 elapsedTimer _timer_exit_phase2;
2012 elapsedTimer _timer_exit_phase3;
2013 elapsedTimer _timer_exit_phase4;
2014
2015 if (log_is_enabled(Debug, os, thread, timer)) {
2016 _timer_exit_phase1.start();
2017 }
2018
2019 HandleMark hm(this);
2020 Handle uncaught_exception(this, this->pending_exception());
2021 this->clear_pending_exception();
2022 Handle threadObj(this, this->threadObj());
2023 assert(threadObj.not_null(), "Java thread object should be created");
2024
2025 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
2026 {
2027 EXCEPTION_MARK;
2028
2029 CLEAR_PENDING_EXCEPTION;
2030 }
2031 if (!destroy_vm) {
2032 if (uncaught_exception.not_null()) {
2033 EXCEPTION_MARK;
2034 // Call method Thread.dispatchUncaughtException().
2035 Klass* thread_klass = SystemDictionary::Thread_klass();
2036 JavaValue result(T_VOID);
2037 JavaCalls::call_virtual(&result,
2038 threadObj, thread_klass,
2039 vmSymbols::dispatchUncaughtException_name(),
2040 vmSymbols::throwable_void_signature(),
2041 uncaught_exception,
2042 THREAD);
2043 if (HAS_PENDING_EXCEPTION) {
2044 ResourceMark rm(this);
2045 jio_fprintf(defaultStream::error_stream(),
2046 "\nException: %s thrown from the UncaughtExceptionHandler"
2047 " in thread \"%s\"\n",
2048 pending_exception()->klass()->external_name(),
2049 get_thread_name());
2050 CLEAR_PENDING_EXCEPTION;
2051 }
2052 }
2053 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
2054
2055 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
2056 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
2057 // is deprecated anyhow.
2058 if (!is_Compiler_thread()) {
2059 int count = 3;
2060 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
2061 EXCEPTION_MARK;
2062 JavaValue result(T_VOID);
2063 Klass* thread_klass = SystemDictionary::Thread_klass();
2064 JavaCalls::call_virtual(&result,
2065 threadObj, thread_klass,
2066 vmSymbols::exit_method_name(),
2067 vmSymbols::void_method_signature(),
2068 THREAD);
2069 CLEAR_PENDING_EXCEPTION;
2070 }
2071 }
2072 // notify JVMTI
2073 if (JvmtiExport::should_post_thread_life()) {
2074 JvmtiExport::post_thread_end(this);
2075 }
2076
2077 // We have notified the agents that we are exiting, before we go on,
2078 // we must check for a pending external suspend request and honor it
2079 // in order to not surprise the thread that made the suspend request.
2080 while (true) {
2081 {
2082 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2083 if (!is_external_suspend()) {
2084 set_terminated(_thread_exiting);
2085 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
2086 break;
2087 }
2088 // Implied else:
2089 // Things get a little tricky here. We have a pending external
2090 // suspend request, but we are holding the SR_lock so we
2091 // can't just self-suspend. So we temporarily drop the lock
2092 // and then self-suspend.
2093 }
2094
2095 ThreadBlockInVM tbivm(this);
2096 java_suspend_self();
2097
2098 // We're done with this suspend request, but we have to loop around
2099 // and check again. Eventually we will get SR_lock without a pending
2100 // external suspend request and will be able to mark ourselves as
2101 // exiting.
2102 }
2103 // no more external suspends are allowed at this point
2104 } else {
2105 assert(!is_terminated() && !is_exiting(), "must not be exiting");
2106 // before_exit() has already posted JVMTI THREAD_END events
2107 }
2108
2109 if (log_is_enabled(Debug, os, thread, timer)) {
2110 _timer_exit_phase1.stop();
2111 _timer_exit_phase2.start();
2112 }
2113
2114 // Capture daemon status before the thread is marked as terminated.
2115 bool daemon = is_daemon(threadObj());
2116
2117 // Notify waiters on thread object. This has to be done after exit() is called
2118 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
2119 // group should have the destroyed bit set before waiters are notified).
2120 ensure_join(this);
2121 assert(!this->has_pending_exception(), "ensure_join should have cleared");
2122
2123 if (log_is_enabled(Debug, os, thread, timer)) {
2124 _timer_exit_phase2.stop();
2125 _timer_exit_phase3.start();
2126 }
2127 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
2128 // held by this thread must be released. The spec does not distinguish
2129 // between JNI-acquired and regular Java monitors. We can only see
2130 // regular Java monitors here if monitor enter-exit matching is broken.
2131 //
2132 // ensure_join() ignores IllegalThreadStateExceptions, and so does
2133 // ObjectSynchronizer::release_monitors_owned_by_thread().
2134 if (exit_type == jni_detach) {
2135 // Sanity check even though JNI DetachCurrentThread() would have
2136 // returned JNI_ERR if there was a Java frame. JavaThread exit
2137 // should be done executing Java code by the time we get here.
2138 assert(!this->has_last_Java_frame(),
2139 "should not have a Java frame when detaching or exiting");
2140 ObjectSynchronizer::release_monitors_owned_by_thread(this);
2141 assert(!this->has_pending_exception(), "release_monitors should have cleared");
2142 }
2143
2144 // These things needs to be done while we are still a Java Thread. Make sure that thread
2145 // is in a consistent state, in case GC happens
2146 JFR_ONLY(Jfr::on_thread_exit(this);)
2147
2148 if (active_handles() != NULL) {
2149 JNIHandleBlock* block = active_handles();
2150 set_active_handles(NULL);
2151 JNIHandleBlock::release_block(block);
2152 }
2153
2154 if (free_handle_block() != NULL) {
2155 JNIHandleBlock* block = free_handle_block();
2156 set_free_handle_block(NULL);
2157 JNIHandleBlock::release_block(block);
2158 }
2159
2160 // These have to be removed while this is still a valid thread.
2161 remove_stack_guard_pages();
2162
2163 if (UseTLAB) {
2164 tlab().retire();
2165 }
2166
2167 if (JvmtiEnv::environments_might_exist()) {
2168 JvmtiExport::cleanup_thread(this);
2169 }
2170
2171 // We must flush any deferred card marks and other various GC barrier
2172 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2173 // before removing a thread from the list of active threads.
2174 BarrierSet::barrier_set()->on_thread_detach(this);
2175
2176 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2177 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2178 os::current_thread_id());
2179
2180 if (log_is_enabled(Debug, os, thread, timer)) {
2181 _timer_exit_phase3.stop();
2182 _timer_exit_phase4.start();
2183 }
2184 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2185 Threads::remove(this, daemon);
2186
2187 if (log_is_enabled(Debug, os, thread, timer)) {
2188 _timer_exit_phase4.stop();
2189 ResourceMark rm(this);
2190 log_debug(os, thread, timer)("name='%s'"
2191 ", exit-phase1=" JLONG_FORMAT
2192 ", exit-phase2=" JLONG_FORMAT
2193 ", exit-phase3=" JLONG_FORMAT
2194 ", exit-phase4=" JLONG_FORMAT,
2195 get_thread_name(),
2196 _timer_exit_phase1.milliseconds(),
2197 _timer_exit_phase2.milliseconds(),
2198 _timer_exit_phase3.milliseconds(),
2199 _timer_exit_phase4.milliseconds());
2200 }
2201 }
2202
2203 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
2204 if (active_handles() != NULL) {
2205 JNIHandleBlock* block = active_handles();
2206 set_active_handles(NULL);
2207 JNIHandleBlock::release_block(block);
2208 }
2209
2210 if (free_handle_block() != NULL) {
2211 JNIHandleBlock* block = free_handle_block();
2212 set_free_handle_block(NULL);
2213 JNIHandleBlock::release_block(block);
2214 }
2215
2216 // These have to be removed while this is still a valid thread.
2217 remove_stack_guard_pages();
2218
2219 if (UseTLAB) {
2220 tlab().retire();
2221 }
2222
2223 BarrierSet::barrier_set()->on_thread_detach(this);
2224
2225 Threads::remove(this, is_daemon);
2226 this->smr_delete();
2227 }
2228
2229 JavaThread* JavaThread::active() {
2230 Thread* thread = Thread::current();
2231 if (thread->is_Java_thread()) {
2232 return (JavaThread*) thread;
2233 } else {
2234 assert(thread->is_VM_thread(), "this must be a vm thread");
2235 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2236 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2237 assert(ret->is_Java_thread(), "must be a Java thread");
2238 return ret;
2239 }
2240 }
2241
2242 bool JavaThread::is_lock_owned(address adr) const {
2243 if (Thread::is_lock_owned(adr)) return true;
2244
2245 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2246 if (chunk->contains(adr)) return true;
2247 }
2248
2249 return false;
2250 }
2251
2252
2253 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2254 chunk->set_next(monitor_chunks());
2255 set_monitor_chunks(chunk);
2256 }
2257
2258 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2259 guarantee(monitor_chunks() != NULL, "must be non empty");
2260 if (monitor_chunks() == chunk) {
2261 set_monitor_chunks(chunk->next());
2262 } else {
2263 MonitorChunk* prev = monitor_chunks();
2264 while (prev->next() != chunk) prev = prev->next();
2265 prev->set_next(chunk->next());
2266 }
2267 }
2268
2269 // JVM support.
2270
2271 // Note: this function shouldn't block if it's called in
2272 // _thread_in_native_trans state (such as from
2273 // check_special_condition_for_native_trans()).
2274 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2275
2276 if (has_last_Java_frame() && has_async_condition()) {
2277 // If we are at a polling page safepoint (not a poll return)
2278 // then we must defer async exception because live registers
2279 // will be clobbered by the exception path. Poll return is
2280 // ok because the call we a returning from already collides
2281 // with exception handling registers and so there is no issue.
2282 // (The exception handling path kills call result registers but
2283 // this is ok since the exception kills the result anyway).
2284
2285 if (is_at_poll_safepoint()) {
2286 // if the code we are returning to has deoptimized we must defer
2287 // the exception otherwise live registers get clobbered on the
2288 // exception path before deoptimization is able to retrieve them.
2289 //
2290 RegisterMap map(this, false);
2291 frame caller_fr = last_frame().sender(&map);
2292 assert(caller_fr.is_compiled_frame(), "what?");
2293 if (caller_fr.is_deoptimized_frame()) {
2294 log_info(exceptions)("deferred async exception at compiled safepoint");
2295 return;
2296 }
2297 }
2298 }
2299
2300 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2301 if (condition == _no_async_condition) {
2302 // Conditions have changed since has_special_runtime_exit_condition()
2303 // was called:
2304 // - if we were here only because of an external suspend request,
2305 // then that was taken care of above (or cancelled) so we are done
2306 // - if we were here because of another async request, then it has
2307 // been cleared between the has_special_runtime_exit_condition()
2308 // and now so again we are done
2309 return;
2310 }
2311
2312 // Check for pending async. exception
2313 if (_pending_async_exception != NULL) {
2314 // Only overwrite an already pending exception, if it is not a threadDeath.
2315 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2316
2317 // We cannot call Exceptions::_throw(...) here because we cannot block
2318 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2319
2320 LogTarget(Info, exceptions) lt;
2321 if (lt.is_enabled()) {
2322 ResourceMark rm;
2323 LogStream ls(lt);
2324 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2325 if (has_last_Java_frame()) {
2326 frame f = last_frame();
2327 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2328 }
2329 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2330 }
2331 _pending_async_exception = NULL;
2332 clear_has_async_exception();
2333 }
2334 }
2335
2336 if (check_unsafe_error &&
2337 condition == _async_unsafe_access_error && !has_pending_exception()) {
2338 condition = _no_async_condition; // done
2339 switch (thread_state()) {
2340 case _thread_in_vm: {
2341 JavaThread* THREAD = this;
2342 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2343 }
2344 case _thread_in_native: {
2345 ThreadInVMfromNative tiv(this);
2346 JavaThread* THREAD = this;
2347 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2348 }
2349 case _thread_in_Java: {
2350 ThreadInVMfromJava tiv(this);
2351 JavaThread* THREAD = this;
2352 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2353 }
2354 default:
2355 ShouldNotReachHere();
2356 }
2357 }
2358
2359 assert(condition == _no_async_condition || has_pending_exception() ||
2360 (!check_unsafe_error && condition == _async_unsafe_access_error),
2361 "must have handled the async condition, if no exception");
2362 }
2363
2364 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2365
2366 // Check for pending external suspend.
2367 if (is_external_suspend_with_lock()) {
2368 frame_anchor()->make_walkable(this);
2369 java_suspend_self_with_safepoint_check();
2370 }
2371
2372 // We might be here for reasons in addition to the self-suspend request
2373 // so check for other async requests.
2374 if (check_asyncs) {
2375 check_and_handle_async_exceptions();
2376 }
2377
2378 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2379 }
2380
2381 void JavaThread::send_thread_stop(oop java_throwable) {
2382 ResourceMark rm;
2383 assert(Thread::current()->is_VM_thread() || Thread::current() == this, "should be in the vm thread");
2384
2385 // Do not throw asynchronous exceptions against the compiler thread
2386 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2387 if (!can_call_java()) return;
2388
2389 {
2390 // Actually throw the Throwable against the target Thread - however
2391 // only if there is no thread death exception installed already.
2392 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2393 // If the topmost frame is a runtime stub, then we are calling into
2394 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2395 // must deoptimize the caller before continuing, as the compiled exception handler table
2396 // may not be valid
2397 if (has_last_Java_frame()) {
2398 frame f = last_frame();
2399 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2400 RegisterMap reg_map(this, false);
2401 frame compiled_frame = f.sender(®_map);
2402 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2403 Deoptimization::deoptimize(this, compiled_frame);
2404 }
2405 }
2406 }
2407
2408 // Set async. pending exception in thread.
2409 set_pending_async_exception(java_throwable);
2410
2411 if (log_is_enabled(Info, exceptions)) {
2412 ResourceMark rm;
2413 log_info(exceptions)("Pending Async. exception installed of type: %s",
2414 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2415 }
2416 // for AbortVMOnException flag
2417 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2418 }
2419 }
2420
2421
2422 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
2423 java_lang_Thread::set_interrupted(threadObj(), true);
2424 this->interrupt();
2425 }
2426
2427 // External suspension mechanism.
2428 //
2429 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2430 // to any VM_locks and it is at a transition
2431 // Self-suspension will happen on the transition out of the vm.
2432 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2433 //
2434 // Guarantees on return:
2435 // + Target thread will not execute any new bytecode (that's why we need to
2436 // force a safepoint)
2437 // + Target thread will not enter any new monitors
2438 //
2439 void JavaThread::java_suspend() {
2440 ThreadsListHandle tlh;
2441 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2442 return;
2443 }
2444
2445 { MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2446 if (!is_external_suspend()) {
2447 // a racing resume has cancelled us; bail out now
2448 return;
2449 }
2450
2451 // suspend is done
2452 uint32_t debug_bits = 0;
2453 // Warning: is_ext_suspend_completed() may temporarily drop the
2454 // SR_lock to allow the thread to reach a stable thread state if
2455 // it is currently in a transient thread state.
2456 if (is_ext_suspend_completed(false /* !called_by_wait */,
2457 SuspendRetryDelay, &debug_bits)) {
2458 return;
2459 }
2460 }
2461
2462 if (Thread::current() == this) {
2463 // Safely self-suspend.
2464 // If we don't do this explicitly it will implicitly happen
2465 // before we transition back to Java, and on some other thread-state
2466 // transition paths, but not as we exit a JVM TI SuspendThread call.
2467 // As SuspendThread(current) must not return (until resumed) we must
2468 // self-suspend here.
2469 ThreadBlockInVM tbivm(this);
2470 java_suspend_self();
2471 } else {
2472 VM_ThreadSuspend vm_suspend;
2473 VMThread::execute(&vm_suspend);
2474 }
2475 }
2476
2477 // Part II of external suspension.
2478 // A JavaThread self suspends when it detects a pending external suspend
2479 // request. This is usually on transitions. It is also done in places
2480 // where continuing to the next transition would surprise the caller,
2481 // e.g., monitor entry.
2482 //
2483 // Returns the number of times that the thread self-suspended.
2484 //
2485 // Note: DO NOT call java_suspend_self() when you just want to block current
2486 // thread. java_suspend_self() is the second stage of cooperative
2487 // suspension for external suspend requests and should only be used
2488 // to complete an external suspend request.
2489 //
2490 int JavaThread::java_suspend_self() {
2491 assert(thread_state() == _thread_blocked, "wrong state for java_suspend_self()");
2492 int ret = 0;
2493
2494 // we are in the process of exiting so don't suspend
2495 if (is_exiting()) {
2496 clear_external_suspend();
2497 return ret;
2498 }
2499
2500 assert(_anchor.walkable() ||
2501 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2502 "must have walkable stack");
2503
2504 MonitorLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2505
2506 assert(!this->is_ext_suspended(),
2507 "a thread trying to self-suspend should not already be suspended");
2508
2509 if (this->is_suspend_equivalent()) {
2510 // If we are self-suspending as a result of the lifting of a
2511 // suspend equivalent condition, then the suspend_equivalent
2512 // flag is not cleared until we set the ext_suspended flag so
2513 // that wait_for_ext_suspend_completion() returns consistent
2514 // results.
2515 this->clear_suspend_equivalent();
2516 }
2517
2518 // A racing resume may have cancelled us before we grabbed SR_lock
2519 // above. Or another external suspend request could be waiting for us
2520 // by the time we return from SR_lock()->wait(). The thread
2521 // that requested the suspension may already be trying to walk our
2522 // stack and if we return now, we can change the stack out from under
2523 // it. This would be a "bad thing (TM)" and cause the stack walker
2524 // to crash. We stay self-suspended until there are no more pending
2525 // external suspend requests.
2526 while (is_external_suspend()) {
2527 ret++;
2528 this->set_ext_suspended();
2529
2530 // _ext_suspended flag is cleared by java_resume()
2531 while (is_ext_suspended()) {
2532 ml.wait();
2533 }
2534 }
2535 return ret;
2536 }
2537
2538 // Helper routine to set up the correct thread state before calling java_suspend_self.
2539 // This is called when regular thread-state transition helpers can't be used because
2540 // we can be in various states, in particular _thread_in_native_trans.
2541 // Because this thread is external suspended the safepoint code will count it as at
2542 // a safepoint, regardless of what its actual current thread-state is. But
2543 // is_ext_suspend_completed() may be waiting to see a thread transition from
2544 // _thread_in_native_trans to _thread_blocked. So we set the thread state directly
2545 // to _thread_blocked. The problem with setting thread state directly is that a
2546 // safepoint could happen just after java_suspend_self() returns after being resumed,
2547 // and the VM thread will see the _thread_blocked state. So we must check for a safepoint
2548 // after restoring the state to make sure we won't leave while a safepoint is in progress.
2549 // However, not all initial-states are allowed when performing a safepoint check, as we
2550 // should never be blocking at a safepoint whilst in those states. Of these 'bad' states
2551 // only _thread_in_native is possible when executing this code (based on our two callers).
2552 // A thread that is _thread_in_native is already safepoint-safe and so it doesn't matter
2553 // whether the VMThread sees the _thread_blocked state, or the _thread_in_native state,
2554 // and so we don't need the explicit safepoint check.
2555
2556 void JavaThread::java_suspend_self_with_safepoint_check() {
2557 assert(this == Thread::current(), "invariant");
2558 JavaThreadState state = thread_state();
2559 set_thread_state(_thread_blocked);
2560 java_suspend_self();
2561 set_thread_state_fence(state);
2562 // Since we are not using a regular thread-state transition helper here,
2563 // we must manually emit the instruction barrier after leaving a safe state.
2564 OrderAccess::cross_modify_fence();
2565 if (state != _thread_in_native) {
2566 SafepointMechanism::block_if_requested(this);
2567 }
2568 }
2569
2570 #ifdef ASSERT
2571 // Verify the JavaThread has not yet been published in the Threads::list, and
2572 // hence doesn't need protection from concurrent access at this stage.
2573 void JavaThread::verify_not_published() {
2574 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2575 // since an unpublished JavaThread doesn't participate in the
2576 // Thread-SMR protocol for keeping a ThreadsList alive.
2577 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2578 }
2579 #endif
2580
2581 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2582 // progress or when _suspend_flags is non-zero.
2583 // Current thread needs to self-suspend if there is a suspend request and/or
2584 // block if a safepoint is in progress.
2585 // Async exception ISN'T checked.
2586 // Note only the ThreadInVMfromNative transition can call this function
2587 // directly and when thread state is _thread_in_native_trans
2588 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2589 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2590
2591 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2592
2593 if (thread->is_external_suspend()) {
2594 thread->java_suspend_self_with_safepoint_check();
2595 } else {
2596 SafepointMechanism::block_if_requested(thread);
2597 }
2598
2599 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2600 }
2601
2602 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2603 // progress or when _suspend_flags is non-zero.
2604 // Current thread needs to self-suspend if there is a suspend request and/or
2605 // block if a safepoint is in progress.
2606 // Also check for pending async exception (not including unsafe access error).
2607 // Note only the native==>VM/Java barriers can call this function and when
2608 // thread state is _thread_in_native_trans.
2609 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2610 check_safepoint_and_suspend_for_native_trans(thread);
2611
2612 if (thread->has_async_exception()) {
2613 // We are in _thread_in_native_trans state, don't handle unsafe
2614 // access error since that may block.
2615 thread->check_and_handle_async_exceptions(false);
2616 }
2617 }
2618
2619 // This is a variant of the normal
2620 // check_special_condition_for_native_trans with slightly different
2621 // semantics for use by critical native wrappers. It does all the
2622 // normal checks but also performs the transition back into
2623 // thread_in_Java state. This is required so that critical natives
2624 // can potentially block and perform a GC if they are the last thread
2625 // exiting the GCLocker.
2626 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2627 check_special_condition_for_native_trans(thread);
2628
2629 // Finish the transition
2630 thread->set_thread_state(_thread_in_Java);
2631
2632 if (thread->do_critical_native_unlock()) {
2633 ThreadInVMfromJavaNoAsyncException tiv(thread);
2634 GCLocker::unlock_critical(thread);
2635 thread->clear_critical_native_unlock();
2636 }
2637 }
2638
2639 // We need to guarantee the Threads_lock here, since resumes are not
2640 // allowed during safepoint synchronization
2641 // Can only resume from an external suspension
2642 void JavaThread::java_resume() {
2643 assert_locked_or_safepoint(Threads_lock);
2644
2645 // Sanity check: thread is gone, has started exiting or the thread
2646 // was not externally suspended.
2647 ThreadsListHandle tlh;
2648 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2649 return;
2650 }
2651
2652 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2653
2654 clear_external_suspend();
2655
2656 if (is_ext_suspended()) {
2657 clear_ext_suspended();
2658 SR_lock()->notify_all();
2659 }
2660 }
2661
2662 size_t JavaThread::_stack_red_zone_size = 0;
2663 size_t JavaThread::_stack_yellow_zone_size = 0;
2664 size_t JavaThread::_stack_reserved_zone_size = 0;
2665 size_t JavaThread::_stack_shadow_zone_size = 0;
2666
2667 void JavaThread::create_stack_guard_pages() {
2668 if (!os::uses_stack_guard_pages() ||
2669 _stack_guard_state != stack_guard_unused ||
2670 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2671 log_info(os, thread)("Stack guard page creation for thread "
2672 UINTX_FORMAT " disabled", os::current_thread_id());
2673 return;
2674 }
2675 address low_addr = stack_end();
2676 size_t len = stack_guard_zone_size();
2677
2678 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2679 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2680
2681 int must_commit = os::must_commit_stack_guard_pages();
2682 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2683
2684 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2685 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2686 return;
2687 }
2688
2689 if (os::guard_memory((char *) low_addr, len)) {
2690 _stack_guard_state = stack_guard_enabled;
2691 } else {
2692 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2693 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2694 if (os::uncommit_memory((char *) low_addr, len)) {
2695 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2696 }
2697 return;
2698 }
2699
2700 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2701 PTR_FORMAT "-" PTR_FORMAT ".",
2702 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2703 }
2704
2705 void JavaThread::remove_stack_guard_pages() {
2706 assert(Thread::current() == this, "from different thread");
2707 if (_stack_guard_state == stack_guard_unused) return;
2708 address low_addr = stack_end();
2709 size_t len = stack_guard_zone_size();
2710
2711 if (os::must_commit_stack_guard_pages()) {
2712 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2713 _stack_guard_state = stack_guard_unused;
2714 } else {
2715 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2716 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2717 return;
2718 }
2719 } else {
2720 if (_stack_guard_state == stack_guard_unused) return;
2721 if (os::unguard_memory((char *) low_addr, len)) {
2722 _stack_guard_state = stack_guard_unused;
2723 } else {
2724 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2725 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2726 return;
2727 }
2728 }
2729
2730 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2731 PTR_FORMAT "-" PTR_FORMAT ".",
2732 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2733 }
2734
2735 void JavaThread::enable_stack_reserved_zone() {
2736 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state");
2737
2738 // The base notation is from the stack's point of view, growing downward.
2739 // We need to adjust it to work correctly with guard_memory()
2740 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2741
2742 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2743 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2744
2745 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2746 _stack_guard_state = stack_guard_enabled;
2747 } else {
2748 warning("Attempt to guard stack reserved zone failed.");
2749 }
2750 enable_register_stack_guard();
2751 }
2752
2753 void JavaThread::disable_stack_reserved_zone() {
2754 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state");
2755
2756 // Simply return if called for a thread that does not use guard pages.
2757 if (_stack_guard_state != stack_guard_enabled) return;
2758
2759 // The base notation is from the stack's point of view, growing downward.
2760 // We need to adjust it to work correctly with guard_memory()
2761 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2762
2763 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2764 _stack_guard_state = stack_guard_reserved_disabled;
2765 } else {
2766 warning("Attempt to unguard stack reserved zone failed.");
2767 }
2768 disable_register_stack_guard();
2769 }
2770
2771 void JavaThread::enable_stack_yellow_reserved_zone() {
2772 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2773 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2774
2775 // The base notation is from the stacks point of view, growing downward.
2776 // We need to adjust it to work correctly with guard_memory()
2777 address base = stack_red_zone_base();
2778
2779 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2780 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2781
2782 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2783 _stack_guard_state = stack_guard_enabled;
2784 } else {
2785 warning("Attempt to guard stack yellow zone failed.");
2786 }
2787 enable_register_stack_guard();
2788 }
2789
2790 void JavaThread::disable_stack_yellow_reserved_zone() {
2791 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2792 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2793
2794 // Simply return if called for a thread that does not use guard pages.
2795 if (_stack_guard_state == stack_guard_unused) return;
2796
2797 // The base notation is from the stacks point of view, growing downward.
2798 // We need to adjust it to work correctly with guard_memory()
2799 address base = stack_red_zone_base();
2800
2801 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2802 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2803 } else {
2804 warning("Attempt to unguard stack yellow zone failed.");
2805 }
2806 disable_register_stack_guard();
2807 }
2808
2809 void JavaThread::enable_stack_red_zone() {
2810 // The base notation is from the stacks point of view, growing downward.
2811 // We need to adjust it to work correctly with guard_memory()
2812 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2813 address base = stack_red_zone_base() - stack_red_zone_size();
2814
2815 guarantee(base < stack_base(), "Error calculating stack red zone");
2816 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2817
2818 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2819 warning("Attempt to guard stack red zone failed.");
2820 }
2821 }
2822
2823 void JavaThread::disable_stack_red_zone() {
2824 // The base notation is from the stacks point of view, growing downward.
2825 // We need to adjust it to work correctly with guard_memory()
2826 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2827 address base = stack_red_zone_base() - stack_red_zone_size();
2828 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2829 warning("Attempt to unguard stack red zone failed.");
2830 }
2831 }
2832
2833 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2834 // ignore is there is no stack
2835 if (!has_last_Java_frame()) return;
2836 // traverse the stack frames. Starts from top frame.
2837 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2838 frame* fr = fst.current();
2839 f(fr, fst.register_map());
2840 }
2841 }
2842
2843
2844 #ifndef PRODUCT
2845 // Deoptimization
2846 // Function for testing deoptimization
2847 void JavaThread::deoptimize() {
2848 StackFrameStream fst(this, false);
2849 bool deopt = false; // Dump stack only if a deopt actually happens.
2850 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2851 // Iterate over all frames in the thread and deoptimize
2852 for (; !fst.is_done(); fst.next()) {
2853 if (fst.current()->can_be_deoptimized()) {
2854
2855 if (only_at) {
2856 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2857 // consists of comma or carriage return separated numbers so
2858 // search for the current bci in that string.
2859 address pc = fst.current()->pc();
2860 nmethod* nm = (nmethod*) fst.current()->cb();
2861 ScopeDesc* sd = nm->scope_desc_at(pc);
2862 char buffer[8];
2863 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2864 size_t len = strlen(buffer);
2865 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2866 while (found != NULL) {
2867 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2868 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2869 // Check that the bci found is bracketed by terminators.
2870 break;
2871 }
2872 found = strstr(found + 1, buffer);
2873 }
2874 if (!found) {
2875 continue;
2876 }
2877 }
2878
2879 if (DebugDeoptimization && !deopt) {
2880 deopt = true; // One-time only print before deopt
2881 tty->print_cr("[BEFORE Deoptimization]");
2882 trace_frames();
2883 trace_stack();
2884 }
2885 Deoptimization::deoptimize(this, *fst.current());
2886 }
2887 }
2888
2889 if (DebugDeoptimization && deopt) {
2890 tty->print_cr("[AFTER Deoptimization]");
2891 trace_frames();
2892 }
2893 }
2894
2895
2896 // Make zombies
2897 void JavaThread::make_zombies() {
2898 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2899 if (fst.current()->can_be_deoptimized()) {
2900 // it is a Java nmethod
2901 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2902 nm->make_not_entrant();
2903 }
2904 }
2905 }
2906 #endif // PRODUCT
2907
2908
2909 void JavaThread::deoptimize_marked_methods() {
2910 if (!has_last_Java_frame()) return;
2911 StackFrameStream fst(this, false);
2912 for (; !fst.is_done(); fst.next()) {
2913 if (fst.current()->should_be_deoptimized()) {
2914 Deoptimization::deoptimize(this, *fst.current());
2915 }
2916 }
2917 }
2918
2919 // If the caller is a NamedThread, then remember, in the current scope,
2920 // the given JavaThread in its _processed_thread field.
2921 class RememberProcessedThread: public StackObj {
2922 NamedThread* _cur_thr;
2923 public:
2924 RememberProcessedThread(JavaThread* jthr) {
2925 Thread* thread = Thread::current();
2926 if (thread->is_Named_thread()) {
2927 _cur_thr = (NamedThread *)thread;
2928 _cur_thr->set_processed_thread(jthr);
2929 } else {
2930 _cur_thr = NULL;
2931 }
2932 }
2933
2934 ~RememberProcessedThread() {
2935 if (_cur_thr) {
2936 _cur_thr->set_processed_thread(NULL);
2937 }
2938 }
2939 };
2940
2941 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2942 // Verify that the deferred card marks have been flushed.
2943 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2944
2945 // Traverse the GCHandles
2946 Thread::oops_do(f, cf);
2947
2948 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2949 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2950
2951 if (has_last_Java_frame()) {
2952 // Record JavaThread to GC thread
2953 RememberProcessedThread rpt(this);
2954
2955 // traverse the registered growable array
2956 if (_array_for_gc != NULL) {
2957 for (int index = 0; index < _array_for_gc->length(); index++) {
2958 f->do_oop(_array_for_gc->adr_at(index));
2959 }
2960 }
2961
2962 // Traverse the monitor chunks
2963 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2964 chunk->oops_do(f);
2965 }
2966
2967 // Traverse the execution stack
2968 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2969 fst.current()->oops_do(f, cf, fst.register_map());
2970 }
2971 }
2972
2973 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2974 // If we have deferred set_locals there might be oops waiting to be
2975 // written
2976 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2977 if (list != NULL) {
2978 for (int i = 0; i < list->length(); i++) {
2979 list->at(i)->oops_do(f);
2980 }
2981 }
2982
2983 // Traverse instance variables at the end since the GC may be moving things
2984 // around using this function
2985 f->do_oop((oop*) &_threadObj);
2986 f->do_oop((oop*) &_vm_result);
2987 f->do_oop((oop*) &_exception_oop);
2988 f->do_oop((oop*) &_pending_async_exception);
2989
2990 if (jvmti_thread_state() != NULL) {
2991 jvmti_thread_state()->oops_do(f, cf);
2992 }
2993 }
2994
2995 #ifdef ASSERT
2996 void JavaThread::verify_states_for_handshake() {
2997 // This checks that the thread has a correct frame state during a handshake.
2998 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2999 (has_last_Java_frame() && java_call_counter() > 0),
3000 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
3001 has_last_Java_frame(), java_call_counter());
3002 }
3003 #endif
3004
3005 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
3006 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
3007 (has_last_Java_frame() && java_call_counter() > 0),
3008 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
3009 has_last_Java_frame(), java_call_counter());
3010
3011 if (has_last_Java_frame()) {
3012 // Traverse the execution stack
3013 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3014 fst.current()->nmethods_do(cf);
3015 }
3016 }
3017
3018 if (jvmti_thread_state() != NULL) {
3019 jvmti_thread_state()->nmethods_do(cf);
3020 }
3021 }
3022
3023 void JavaThread::metadata_do(MetadataClosure* f) {
3024 if (has_last_Java_frame()) {
3025 // Traverse the execution stack to call f() on the methods in the stack
3026 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3027 fst.current()->metadata_do(f);
3028 }
3029 } else if (is_Compiler_thread()) {
3030 // need to walk ciMetadata in current compile tasks to keep alive.
3031 CompilerThread* ct = (CompilerThread*)this;
3032 if (ct->env() != NULL) {
3033 ct->env()->metadata_do(f);
3034 }
3035 CompileTask* task = ct->task();
3036 if (task != NULL) {
3037 task->metadata_do(f);
3038 }
3039 }
3040 }
3041
3042 // Printing
3043 const char* _get_thread_state_name(JavaThreadState _thread_state) {
3044 switch (_thread_state) {
3045 case _thread_uninitialized: return "_thread_uninitialized";
3046 case _thread_new: return "_thread_new";
3047 case _thread_new_trans: return "_thread_new_trans";
3048 case _thread_in_native: return "_thread_in_native";
3049 case _thread_in_native_trans: return "_thread_in_native_trans";
3050 case _thread_in_vm: return "_thread_in_vm";
3051 case _thread_in_vm_trans: return "_thread_in_vm_trans";
3052 case _thread_in_Java: return "_thread_in_Java";
3053 case _thread_in_Java_trans: return "_thread_in_Java_trans";
3054 case _thread_blocked: return "_thread_blocked";
3055 case _thread_blocked_trans: return "_thread_blocked_trans";
3056 default: return "unknown thread state";
3057 }
3058 }
3059
3060 #ifndef PRODUCT
3061 void JavaThread::print_thread_state_on(outputStream *st) const {
3062 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
3063 };
3064 #endif // PRODUCT
3065
3066 // Called by Threads::print() for VM_PrintThreads operation
3067 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
3068 st->print_raw("\"");
3069 st->print_raw(get_thread_name());
3070 st->print_raw("\" ");
3071 oop thread_oop = threadObj();
3072 if (thread_oop != NULL) {
3073 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
3074 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
3075 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
3076 }
3077 Thread::print_on(st, print_extended_info);
3078 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
3079 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
3080 if (thread_oop != NULL) {
3081 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3082 }
3083 #ifndef PRODUCT
3084 _safepoint_state->print_on(st);
3085 #endif // PRODUCT
3086 if (is_Compiler_thread()) {
3087 CompileTask *task = ((CompilerThread*)this)->task();
3088 if (task != NULL) {
3089 st->print(" Compiling: ");
3090 task->print(st, NULL, true, false);
3091 } else {
3092 st->print(" No compile task");
3093 }
3094 st->cr();
3095 }
3096 }
3097
3098 void JavaThread::print() const { print_on(tty); }
3099
3100 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3101 st->print("%s", get_thread_name_string(buf, buflen));
3102 }
3103
3104 // Called by fatal error handler. The difference between this and
3105 // JavaThread::print() is that we can't grab lock or allocate memory.
3106 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3107 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3108 oop thread_obj = threadObj();
3109 if (thread_obj != NULL) {
3110 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3111 }
3112 st->print(" [");
3113 st->print("%s", _get_thread_state_name(_thread_state));
3114 if (osthread()) {
3115 st->print(", id=%d", osthread()->thread_id());
3116 }
3117 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3118 p2i(stack_end()), p2i(stack_base()));
3119 st->print("]");
3120
3121 ThreadsSMRSupport::print_info_on(this, st);
3122 return;
3123 }
3124
3125 // Verification
3126
3127 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3128
3129 void JavaThread::verify() {
3130 // Verify oops in the thread.
3131 oops_do(&VerifyOopClosure::verify_oop, NULL);
3132
3133 // Verify the stack frames.
3134 frames_do(frame_verify);
3135 }
3136
3137 // CR 6300358 (sub-CR 2137150)
3138 // Most callers of this method assume that it can't return NULL but a
3139 // thread may not have a name whilst it is in the process of attaching to
3140 // the VM - see CR 6412693, and there are places where a JavaThread can be
3141 // seen prior to having it's threadObj set (eg JNI attaching threads and
3142 // if vm exit occurs during initialization). These cases can all be accounted
3143 // for such that this method never returns NULL.
3144 const char* JavaThread::get_thread_name() const {
3145 #ifdef ASSERT
3146 // early safepoints can hit while current thread does not yet have TLS
3147 if (!SafepointSynchronize::is_at_safepoint()) {
3148 Thread *cur = Thread::current();
3149 if (!(cur->is_Java_thread() && cur == this)) {
3150 // Current JavaThreads are allowed to get their own name without
3151 // the Threads_lock.
3152 assert_locked_or_safepoint_or_handshake(Threads_lock, this);
3153 }
3154 }
3155 #endif // ASSERT
3156 return get_thread_name_string();
3157 }
3158
3159 // Returns a non-NULL representation of this thread's name, or a suitable
3160 // descriptive string if there is no set name
3161 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3162 const char* name_str;
3163 oop thread_obj = threadObj();
3164 if (thread_obj != NULL) {
3165 oop name = java_lang_Thread::name(thread_obj);
3166 if (name != NULL) {
3167 if (buf == NULL) {
3168 name_str = java_lang_String::as_utf8_string(name);
3169 } else {
3170 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3171 }
3172 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3173 name_str = "<no-name - thread is attaching>";
3174 } else {
3175 name_str = Thread::name();
3176 }
3177 } else {
3178 name_str = Thread::name();
3179 }
3180 assert(name_str != NULL, "unexpected NULL thread name");
3181 return name_str;
3182 }
3183
3184 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3185
3186 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3187 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
3188 // Link Java Thread object <-> C++ Thread
3189
3190 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3191 // and put it into a new Handle. The Handle "thread_oop" can then
3192 // be used to pass the C++ thread object to other methods.
3193
3194 // Set the Java level thread object (jthread) field of the
3195 // new thread (a JavaThread *) to C++ thread object using the
3196 // "thread_oop" handle.
3197
3198 // Set the thread field (a JavaThread *) of the
3199 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3200
3201 Handle thread_oop(Thread::current(),
3202 JNIHandles::resolve_non_null(jni_thread));
3203 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3204 "must be initialized");
3205 set_threadObj(thread_oop());
3206 java_lang_Thread::set_thread(thread_oop(), this);
3207
3208 if (prio == NoPriority) {
3209 prio = java_lang_Thread::priority(thread_oop());
3210 assert(prio != NoPriority, "A valid priority should be present");
3211 }
3212
3213 // Push the Java priority down to the native thread; needs Threads_lock
3214 Thread::set_priority(this, prio);
3215
3216 // Add the new thread to the Threads list and set it in motion.
3217 // We must have threads lock in order to call Threads::add.
3218 // It is crucial that we do not block before the thread is
3219 // added to the Threads list for if a GC happens, then the java_thread oop
3220 // will not be visited by GC.
3221 Threads::add(this);
3222 }
3223
3224 oop JavaThread::current_park_blocker() {
3225 // Support for JSR-166 locks
3226 oop thread_oop = threadObj();
3227 if (thread_oop != NULL) {
3228 return java_lang_Thread::park_blocker(thread_oop);
3229 }
3230 return NULL;
3231 }
3232
3233
3234 void JavaThread::print_stack_on(outputStream* st) {
3235 if (!has_last_Java_frame()) return;
3236 ResourceMark rm;
3237 HandleMark hm;
3238
3239 RegisterMap reg_map(this);
3240 vframe* start_vf = last_java_vframe(®_map);
3241 int count = 0;
3242 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3243 if (f->is_java_frame()) {
3244 javaVFrame* jvf = javaVFrame::cast(f);
3245 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3246
3247 // Print out lock information
3248 if (JavaMonitorsInStackTrace) {
3249 jvf->print_lock_info_on(st, count);
3250 }
3251 } else {
3252 // Ignore non-Java frames
3253 }
3254
3255 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3256 count++;
3257 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3258 }
3259 }
3260
3261
3262 // JVMTI PopFrame support
3263 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3264 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3265 if (in_bytes(size_in_bytes) != 0) {
3266 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3267 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3268 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3269 }
3270 }
3271
3272 void* JavaThread::popframe_preserved_args() {
3273 return _popframe_preserved_args;
3274 }
3275
3276 ByteSize JavaThread::popframe_preserved_args_size() {
3277 return in_ByteSize(_popframe_preserved_args_size);
3278 }
3279
3280 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3281 int sz = in_bytes(popframe_preserved_args_size());
3282 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3283 return in_WordSize(sz / wordSize);
3284 }
3285
3286 void JavaThread::popframe_free_preserved_args() {
3287 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3288 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
3289 _popframe_preserved_args = NULL;
3290 _popframe_preserved_args_size = 0;
3291 }
3292
3293 #ifndef PRODUCT
3294
3295 void JavaThread::trace_frames() {
3296 tty->print_cr("[Describe stack]");
3297 int frame_no = 1;
3298 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3299 tty->print(" %d. ", frame_no++);
3300 fst.current()->print_value_on(tty, this);
3301 tty->cr();
3302 }
3303 }
3304
3305 class PrintAndVerifyOopClosure: public OopClosure {
3306 protected:
3307 template <class T> inline void do_oop_work(T* p) {
3308 oop obj = RawAccess<>::oop_load(p);
3309 if (obj == NULL) return;
3310 tty->print(INTPTR_FORMAT ": ", p2i(p));
3311 if (oopDesc::is_oop_or_null(obj)) {
3312 if (obj->is_objArray()) {
3313 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3314 } else {
3315 obj->print();
3316 }
3317 } else {
3318 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3319 }
3320 tty->cr();
3321 }
3322 public:
3323 virtual void do_oop(oop* p) { do_oop_work(p); }
3324 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3325 };
3326
3327 #ifdef ASSERT
3328 // Print or validate the layout of stack frames
3329 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3330 ResourceMark rm;
3331 PRESERVE_EXCEPTION_MARK;
3332 FrameValues values;
3333 int frame_no = 0;
3334 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3335 fst.current()->describe(values, ++frame_no);
3336 if (depth == frame_no) break;
3337 }
3338 if (validate_only) {
3339 values.validate();
3340 } else {
3341 tty->print_cr("[Describe stack layout]");
3342 values.print(this);
3343 }
3344 }
3345 #endif
3346
3347 void JavaThread::trace_stack_from(vframe* start_vf) {
3348 ResourceMark rm;
3349 int vframe_no = 1;
3350 for (vframe* f = start_vf; f; f = f->sender()) {
3351 if (f->is_java_frame()) {
3352 javaVFrame::cast(f)->print_activation(vframe_no++);
3353 } else {
3354 f->print();
3355 }
3356 if (vframe_no > StackPrintLimit) {
3357 tty->print_cr("...<more frames>...");
3358 return;
3359 }
3360 }
3361 }
3362
3363
3364 void JavaThread::trace_stack() {
3365 if (!has_last_Java_frame()) return;
3366 ResourceMark rm;
3367 HandleMark hm;
3368 RegisterMap reg_map(this);
3369 trace_stack_from(last_java_vframe(®_map));
3370 }
3371
3372
3373 #endif // PRODUCT
3374
3375
3376 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3377 assert(reg_map != NULL, "a map must be given");
3378 frame f = last_frame();
3379 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3380 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3381 }
3382 return NULL;
3383 }
3384
3385
3386 Klass* JavaThread::security_get_caller_class(int depth) {
3387 vframeStream vfst(this);
3388 vfst.security_get_caller_frame(depth);
3389 if (!vfst.at_end()) {
3390 return vfst.method()->method_holder();
3391 }
3392 return NULL;
3393 }
3394
3395 // java.lang.Thread.sleep support
3396 // Returns true if sleep time elapsed as expected, and false
3397 // if the thread was interrupted.
3398 bool JavaThread::sleep(jlong millis) {
3399 assert(this == Thread::current(), "thread consistency check");
3400
3401 ParkEvent * const slp = this->_SleepEvent;
3402 // Because there can be races with thread interruption sending an unpark()
3403 // to the event, we explicitly reset it here to avoid an immediate return.
3404 // The actual interrupt state will be checked before we park().
3405 slp->reset();
3406 // Thread interruption establishes a happens-before ordering in the
3407 // Java Memory Model, so we need to ensure we synchronize with the
3408 // interrupt state.
3409 OrderAccess::fence();
3410
3411 jlong prevtime = os::javaTimeNanos();
3412
3413 for (;;) {
3414 // interruption has precedence over timing out
3415 if (this->is_interrupted(true)) {
3416 return false;
3417 }
3418
3419 if (millis <= 0) {
3420 return true;
3421 }
3422
3423 {
3424 ThreadBlockInVM tbivm(this);
3425 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
3426
3427 this->set_suspend_equivalent();
3428 // cleared by handle_special_suspend_equivalent_condition() or
3429 // java_suspend_self() via check_and_wait_while_suspended()
3430
3431 slp->park(millis);
3432
3433 // were we externally suspended while we were waiting?
3434 this->check_and_wait_while_suspended();
3435 }
3436
3437 // Update elapsed time tracking
3438 jlong newtime = os::javaTimeNanos();
3439 if (newtime - prevtime < 0) {
3440 // time moving backwards, should only happen if no monotonic clock
3441 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3442 assert(!os::supports_monotonic_clock(),
3443 "unexpected time moving backwards detected in JavaThread::sleep()");
3444 } else {
3445 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3446 }
3447 prevtime = newtime;
3448 }
3449 }
3450
3451 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3452 assert(thread->is_Compiler_thread(), "must be compiler thread");
3453 CompileBroker::compiler_thread_loop();
3454 }
3455
3456 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3457 NMethodSweeper::sweeper_loop();
3458 }
3459
3460 // Create a CompilerThread
3461 CompilerThread::CompilerThread(CompileQueue* queue,
3462 CompilerCounters* counters)
3463 : JavaThread(&compiler_thread_entry) {
3464 _env = NULL;
3465 _log = NULL;
3466 _task = NULL;
3467 _queue = queue;
3468 _counters = counters;
3469 _buffer_blob = NULL;
3470 _compiler = NULL;
3471
3472 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3473 resource_area()->bias_to(mtCompiler);
3474
3475 #ifndef PRODUCT
3476 _ideal_graph_printer = NULL;
3477 #endif
3478 }
3479
3480 CompilerThread::~CompilerThread() {
3481 // Delete objects which were allocated on heap.
3482 delete _counters;
3483 }
3484
3485 bool CompilerThread::can_call_java() const {
3486 return _compiler != NULL && _compiler->is_jvmci();
3487 }
3488
3489 // Create sweeper thread
3490 CodeCacheSweeperThread::CodeCacheSweeperThread()
3491 : JavaThread(&sweeper_thread_entry) {
3492 _scanned_compiled_method = NULL;
3493 }
3494
3495 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3496 JavaThread::oops_do(f, cf);
3497 if (_scanned_compiled_method != NULL && cf != NULL) {
3498 // Safepoints can occur when the sweeper is scanning an nmethod so
3499 // process it here to make sure it isn't unloaded in the middle of
3500 // a scan.
3501 cf->do_code_blob(_scanned_compiled_method);
3502 }
3503 }
3504
3505 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3506 JavaThread::nmethods_do(cf);
3507 if (_scanned_compiled_method != NULL && cf != NULL) {
3508 // Safepoints can occur when the sweeper is scanning an nmethod so
3509 // process it here to make sure it isn't unloaded in the middle of
3510 // a scan.
3511 cf->do_code_blob(_scanned_compiled_method);
3512 }
3513 }
3514
3515
3516 // ======= Threads ========
3517
3518 // The Threads class links together all active threads, and provides
3519 // operations over all threads. It is protected by the Threads_lock,
3520 // which is also used in other global contexts like safepointing.
3521 // ThreadsListHandles are used to safely perform operations on one
3522 // or more threads without the risk of the thread exiting during the
3523 // operation.
3524 //
3525 // Note: The Threads_lock is currently more widely used than we
3526 // would like. We are actively migrating Threads_lock uses to other
3527 // mechanisms in order to reduce Threads_lock contention.
3528
3529 int Threads::_number_of_threads = 0;
3530 int Threads::_number_of_non_daemon_threads = 0;
3531 int Threads::_return_code = 0;
3532 uintx Threads::_thread_claim_token = 1; // Never zero.
3533 size_t JavaThread::_stack_size_at_create = 0;
3534
3535 #ifdef ASSERT
3536 bool Threads::_vm_complete = false;
3537 #endif
3538
3539 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3540 Prefetch::read((void*)addr, prefetch_interval);
3541 return *addr;
3542 }
3543
3544 // Possibly the ugliest for loop the world has seen. C++ does not allow
3545 // multiple types in the declaration section of the for loop. In this case
3546 // we are only dealing with pointers and hence can cast them. It looks ugly
3547 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3548 #define DO_JAVA_THREADS(LIST, X) \
3549 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3550 *MACRO_list = (JavaThread*)(LIST), \
3551 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3552 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3553 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3554 MACRO_current_p != MACRO_end; \
3555 MACRO_current_p++, \
3556 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3557
3558 // All JavaThreads
3559 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3560
3561 // All NonJavaThreads (i.e., every non-JavaThread in the system).
3562 void Threads::non_java_threads_do(ThreadClosure* tc) {
3563 NoSafepointVerifier nsv;
3564 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
3565 tc->do_thread(njti.current());
3566 }
3567 }
3568
3569 // All JavaThreads
3570 void Threads::java_threads_do(ThreadClosure* tc) {
3571 assert_locked_or_safepoint(Threads_lock);
3572 // ALL_JAVA_THREADS iterates through all JavaThreads.
3573 ALL_JAVA_THREADS(p) {
3574 tc->do_thread(p);
3575 }
3576 }
3577
3578 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3579 assert_locked_or_safepoint(Threads_lock);
3580 java_threads_do(tc);
3581 tc->do_thread(VMThread::vm_thread());
3582 }
3583
3584 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3585 void Threads::threads_do(ThreadClosure* tc) {
3586 assert_locked_or_safepoint(Threads_lock);
3587 java_threads_do(tc);
3588 non_java_threads_do(tc);
3589 }
3590
3591 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3592 uintx claim_token = Threads::thread_claim_token();
3593 ALL_JAVA_THREADS(p) {
3594 if (p->claim_threads_do(is_par, claim_token)) {
3595 tc->do_thread(p);
3596 }
3597 }
3598 VMThread* vmt = VMThread::vm_thread();
3599 if (vmt->claim_threads_do(is_par, claim_token)) {
3600 tc->do_thread(vmt);
3601 }
3602 }
3603
3604 // The system initialization in the library has three phases.
3605 //
3606 // Phase 1: java.lang.System class initialization
3607 // java.lang.System is a primordial class loaded and initialized
3608 // by the VM early during startup. java.lang.System.<clinit>
3609 // only does registerNatives and keeps the rest of the class
3610 // initialization work later until thread initialization completes.
3611 //
3612 // System.initPhase1 initializes the system properties, the static
3613 // fields in, out, and err. Set up java signal handlers, OS-specific
3614 // system settings, and thread group of the main thread.
3615 static void call_initPhase1(TRAPS) {
3616 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3617 JavaValue result(T_VOID);
3618 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3619 vmSymbols::void_method_signature(), CHECK);
3620 }
3621
3622 // Phase 2. Module system initialization
3623 // This will initialize the module system. Only java.base classes
3624 // can be loaded until phase 2 completes.
3625 //
3626 // Call System.initPhase2 after the compiler initialization and jsr292
3627 // classes get initialized because module initialization runs a lot of java
3628 // code, that for performance reasons, should be compiled. Also, this will
3629 // enable the startup code to use lambda and other language features in this
3630 // phase and onward.
3631 //
3632 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3633 static void call_initPhase2(TRAPS) {
3634 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3635
3636 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3637
3638 JavaValue result(T_INT);
3639 JavaCallArguments args;
3640 args.push_int(DisplayVMOutputToStderr);
3641 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3642 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3643 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3644 if (result.get_jint() != JNI_OK) {
3645 vm_exit_during_initialization(); // no message or exception
3646 }
3647
3648 universe_post_module_init();
3649 }
3650
3651 // Phase 3. final setup - set security manager, system class loader and TCCL
3652 //
3653 // This will instantiate and set the security manager, set the system class
3654 // loader as well as the thread context class loader. The security manager
3655 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3656 // other modules or the application's classpath.
3657 static void call_initPhase3(TRAPS) {
3658 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3659 JavaValue result(T_VOID);
3660 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3661 vmSymbols::void_method_signature(), CHECK);
3662 }
3663
3664 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3665 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3666
3667 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3668 create_vm_init_libraries();
3669 }
3670
3671 initialize_class(vmSymbols::java_lang_String(), CHECK);
3672
3673 // Inject CompactStrings value after the static initializers for String ran.
3674 java_lang_String::set_compact_strings(CompactStrings);
3675
3676 // Initialize java_lang.System (needed before creating the thread)
3677 initialize_class(vmSymbols::java_lang_System(), CHECK);
3678 // The VM creates & returns objects of this class. Make sure it's initialized.
3679 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3680 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3681 Handle thread_group = create_initial_thread_group(CHECK);
3682 Universe::set_main_thread_group(thread_group());
3683 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3684 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3685 main_thread->set_threadObj(thread_object);
3686
3687 // Set thread status to running since main thread has
3688 // been started and running.
3689 java_lang_Thread::set_thread_status(thread_object,
3690 java_lang_Thread::RUNNABLE);
3691
3692 // The VM creates objects of this class.
3693 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3694
3695 #ifdef ASSERT
3696 InstanceKlass *k = SystemDictionary::UnsafeConstants_klass();
3697 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
3698 #endif
3699
3700 // initialize the hardware-specific constants needed by Unsafe
3701 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
3702 jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
3703
3704 // The VM preresolves methods to these classes. Make sure that they get initialized
3705 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3706 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3707
3708 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3709 call_initPhase1(CHECK);
3710
3711 // get the Java runtime name, version, and vendor info after java.lang.System is initialized
3712 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3713 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3714 JDK_Version::set_runtime_vendor_version(get_java_runtime_vendor_version(THREAD));
3715 JDK_Version::set_runtime_vendor_vm_bug_url(get_java_runtime_vendor_vm_bug_url(THREAD));
3716
3717 // an instance of OutOfMemory exception has been allocated earlier
3718 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3719 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3720 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3721 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3722 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3723 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3724 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3725 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3726
3727 // Eager box cache initialization only if AOT is on and any library is loaded.
3728 AOTLoader::initialize_box_caches(CHECK);
3729 }
3730
3731 void Threads::initialize_jsr292_core_classes(TRAPS) {
3732 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3733
3734 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3735 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3736 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3737 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3738 }
3739
3740 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3741 extern void JDK_Version_init();
3742
3743 // Preinitialize version info.
3744 VM_Version::early_initialize();
3745
3746 // Check version
3747 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3748
3749 // Initialize library-based TLS
3750 ThreadLocalStorage::init();
3751
3752 // Initialize the output stream module
3753 ostream_init();
3754
3755 // Process java launcher properties.
3756 Arguments::process_sun_java_launcher_properties(args);
3757
3758 // Initialize the os module
3759 os::init();
3760
3761 // Record VM creation timing statistics
3762 TraceVmCreationTime create_vm_timer;
3763 create_vm_timer.start();
3764
3765 // Initialize system properties.
3766 Arguments::init_system_properties();
3767
3768 // So that JDK version can be used as a discriminator when parsing arguments
3769 JDK_Version_init();
3770
3771 // Update/Initialize System properties after JDK version number is known
3772 Arguments::init_version_specific_system_properties();
3773
3774 // Make sure to initialize log configuration *before* parsing arguments
3775 LogConfiguration::initialize(create_vm_timer.begin_time());
3776
3777 // Parse arguments
3778 // Note: this internally calls os::init_container_support()
3779 jint parse_result = Arguments::parse(args);
3780 if (parse_result != JNI_OK) return parse_result;
3781
3782 os::init_before_ergo();
3783
3784 jint ergo_result = Arguments::apply_ergo();
3785 if (ergo_result != JNI_OK) return ergo_result;
3786
3787 // Final check of all ranges after ergonomics which may change values.
3788 if (!JVMFlagRangeList::check_ranges()) {
3789 return JNI_EINVAL;
3790 }
3791
3792 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3793 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo);
3794 if (!constraint_result) {
3795 return JNI_EINVAL;
3796 }
3797
3798 if (PauseAtStartup) {
3799 os::pause();
3800 }
3801
3802 HOTSPOT_VM_INIT_BEGIN();
3803
3804 // Timing (must come after argument parsing)
3805 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3806
3807 // Initialize the os module after parsing the args
3808 jint os_init_2_result = os::init_2();
3809 if (os_init_2_result != JNI_OK) return os_init_2_result;
3810
3811 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3812 // Initialize assert poison page mechanism.
3813 if (ShowRegistersOnAssert) {
3814 initialize_assert_poison();
3815 }
3816 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3817
3818 SafepointMechanism::initialize();
3819
3820 jint adjust_after_os_result = Arguments::adjust_after_os();
3821 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3822
3823 // Initialize output stream logging
3824 ostream_init_log();
3825
3826 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3827 // Must be before create_vm_init_agents()
3828 if (Arguments::init_libraries_at_startup()) {
3829 convert_vm_init_libraries_to_agents();
3830 }
3831
3832 // Launch -agentlib/-agentpath and converted -Xrun agents
3833 if (Arguments::init_agents_at_startup()) {
3834 create_vm_init_agents();
3835 }
3836
3837 // Initialize Threads state
3838 _number_of_threads = 0;
3839 _number_of_non_daemon_threads = 0;
3840
3841 // Initialize global data structures and create system classes in heap
3842 vm_init_globals();
3843
3844 #if INCLUDE_JVMCI
3845 if (JVMCICounterSize > 0) {
3846 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
3847 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3848 } else {
3849 JavaThread::_jvmci_old_thread_counters = NULL;
3850 }
3851 #endif // INCLUDE_JVMCI
3852
3853 // Attach the main thread to this os thread
3854 JavaThread* main_thread = new JavaThread();
3855 main_thread->set_thread_state(_thread_in_vm);
3856 main_thread->initialize_thread_current();
3857 // must do this before set_active_handles
3858 main_thread->record_stack_base_and_size();
3859 main_thread->register_thread_stack_with_NMT();
3860 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3861
3862 if (!main_thread->set_as_starting_thread()) {
3863 vm_shutdown_during_initialization(
3864 "Failed necessary internal allocation. Out of swap space");
3865 main_thread->smr_delete();
3866 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3867 return JNI_ENOMEM;
3868 }
3869
3870 // Enable guard page *after* os::create_main_thread(), otherwise it would
3871 // crash Linux VM, see notes in os_linux.cpp.
3872 main_thread->create_stack_guard_pages();
3873
3874 // Initialize Java-Level synchronization subsystem
3875 ObjectMonitor::Initialize();
3876
3877 // Initialize global modules
3878 jint status = init_globals();
3879 if (status != JNI_OK) {
3880 main_thread->smr_delete();
3881 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3882 return status;
3883 }
3884
3885 JFR_ONLY(Jfr::on_create_vm_1();)
3886
3887 // Should be done after the heap is fully created
3888 main_thread->cache_global_variables();
3889
3890 HandleMark hm;
3891
3892 { MutexLocker mu(Threads_lock);
3893 Threads::add(main_thread);
3894 }
3895
3896 // Any JVMTI raw monitors entered in onload will transition into
3897 // real raw monitor. VM is setup enough here for raw monitor enter.
3898 JvmtiExport::transition_pending_onload_raw_monitors();
3899
3900 // Create the VMThread
3901 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3902
3903 VMThread::create();
3904 Thread* vmthread = VMThread::vm_thread();
3905
3906 if (!os::create_thread(vmthread, os::vm_thread)) {
3907 vm_exit_during_initialization("Cannot create VM thread. "
3908 "Out of system resources.");
3909 }
3910
3911 // Wait for the VM thread to become ready, and VMThread::run to initialize
3912 // Monitors can have spurious returns, must always check another state flag
3913 {
3914 MonitorLocker ml(Notify_lock);
3915 os::start_thread(vmthread);
3916 while (vmthread->active_handles() == NULL) {
3917 ml.wait();
3918 }
3919 }
3920 }
3921
3922 assert(Universe::is_fully_initialized(), "not initialized");
3923 if (VerifyDuringStartup) {
3924 // Make sure we're starting with a clean slate.
3925 VM_Verify verify_op;
3926 VMThread::execute(&verify_op);
3927 }
3928
3929 // We need this to update the java.vm.info property in case any flags used
3930 // to initially define it have been changed. This is needed for both CDS and
3931 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info
3932 // is initially computed. See Abstract_VM_Version::vm_info_string().
3933 // This update must happen before we initialize the java classes, but
3934 // after any initialization logic that might modify the flags.
3935 Arguments::update_vm_info_property(VM_Version::vm_info_string());
3936
3937 Thread* THREAD = Thread::current();
3938
3939 // Always call even when there are not JVMTI environments yet, since environments
3940 // may be attached late and JVMTI must track phases of VM execution
3941 JvmtiExport::enter_early_start_phase();
3942
3943 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3944 JvmtiExport::post_early_vm_start();
3945
3946 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3947
3948 quicken_jni_functions();
3949
3950 // No more stub generation allowed after that point.
3951 StubCodeDesc::freeze();
3952
3953 // Set flag that basic initialization has completed. Used by exceptions and various
3954 // debug stuff, that does not work until all basic classes have been initialized.
3955 set_init_completed();
3956
3957 LogConfiguration::post_initialize();
3958 Metaspace::post_initialize();
3959
3960 HOTSPOT_VM_INIT_END();
3961
3962 // record VM initialization completion time
3963 #if INCLUDE_MANAGEMENT
3964 Management::record_vm_init_completed();
3965 #endif // INCLUDE_MANAGEMENT
3966
3967 // Signal Dispatcher needs to be started before VMInit event is posted
3968 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3969
3970 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3971 if (!DisableAttachMechanism) {
3972 AttachListener::vm_start();
3973 if (StartAttachListener || AttachListener::init_at_startup()) {
3974 AttachListener::init();
3975 }
3976 }
3977
3978 // Launch -Xrun agents
3979 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3980 // back-end can launch with -Xdebug -Xrunjdwp.
3981 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3982 create_vm_init_libraries();
3983 }
3984
3985 if (CleanChunkPoolAsync) {
3986 Chunk::start_chunk_pool_cleaner_task();
3987 }
3988
3989 // Start the service thread
3990 // The service thread enqueues JVMTI deferred events and does various hashtable
3991 // and other cleanups. Needs to start before the compilers start posting events.
3992 ServiceThread::initialize();
3993
3994 // initialize compiler(s)
3995 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3996 #if INCLUDE_JVMCI
3997 bool force_JVMCI_intialization = false;
3998 if (EnableJVMCI) {
3999 // Initialize JVMCI eagerly when it is explicitly requested.
4000 // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
4001 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
4002
4003 if (!force_JVMCI_intialization) {
4004 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
4005 // compilations via JVMCI will not actually block until JVMCI is initialized.
4006 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
4007 }
4008 }
4009 #endif
4010 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
4011 // Postpone completion of compiler initialization to after JVMCI
4012 // is initialized to avoid timeouts of blocking compilations.
4013 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
4014 CompileBroker::compilation_init_phase2();
4015 }
4016 #endif
4017
4018 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
4019 // It is done after compilers are initialized, because otherwise compilations of
4020 // signature polymorphic MH intrinsics can be missed
4021 // (see SystemDictionary::find_method_handle_intrinsic).
4022 initialize_jsr292_core_classes(CHECK_JNI_ERR);
4023
4024 // This will initialize the module system. Only java.base classes can be
4025 // loaded until phase 2 completes
4026 call_initPhase2(CHECK_JNI_ERR);
4027
4028 JFR_ONLY(Jfr::on_create_vm_2();)
4029
4030 // Always call even when there are not JVMTI environments yet, since environments
4031 // may be attached late and JVMTI must track phases of VM execution
4032 JvmtiExport::enter_start_phase();
4033
4034 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
4035 JvmtiExport::post_vm_start();
4036
4037 // Final system initialization including security manager and system class loader
4038 call_initPhase3(CHECK_JNI_ERR);
4039
4040 // cache the system and platform class loaders
4041 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
4042
4043 #if INCLUDE_CDS
4044 // capture the module path info from the ModuleEntryTable
4045 ClassLoader::initialize_module_path(THREAD);
4046 #endif
4047
4048 #if INCLUDE_JVMCI
4049 if (force_JVMCI_intialization) {
4050 JVMCI::initialize_compiler(CHECK_JNI_ERR);
4051 CompileBroker::compilation_init_phase2();
4052 }
4053 #endif
4054
4055 // Always call even when there are not JVMTI environments yet, since environments
4056 // may be attached late and JVMTI must track phases of VM execution
4057 JvmtiExport::enter_live_phase();
4058
4059 // Make perfmemory accessible
4060 PerfMemory::set_accessible(true);
4061
4062 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
4063 JvmtiExport::post_vm_initialized();
4064
4065 JFR_ONLY(Jfr::on_create_vm_3();)
4066
4067 #if INCLUDE_MANAGEMENT
4068 Management::initialize(THREAD);
4069
4070 if (HAS_PENDING_EXCEPTION) {
4071 // management agent fails to start possibly due to
4072 // configuration problem and is responsible for printing
4073 // stack trace if appropriate. Simply exit VM.
4074 vm_exit(1);
4075 }
4076 #endif // INCLUDE_MANAGEMENT
4077
4078 if (MemProfiling) MemProfiler::engage();
4079 StatSampler::engage();
4080 if (CheckJNICalls) JniPeriodicChecker::engage();
4081
4082 BiasedLocking::init();
4083
4084 #if INCLUDE_RTM_OPT
4085 RTMLockingCounters::init();
4086 #endif
4087
4088 call_postVMInitHook(THREAD);
4089 // The Java side of PostVMInitHook.run must deal with all
4090 // exceptions and provide means of diagnosis.
4091 if (HAS_PENDING_EXCEPTION) {
4092 CLEAR_PENDING_EXCEPTION;
4093 }
4094
4095 {
4096 MutexLocker ml(PeriodicTask_lock);
4097 // Make sure the WatcherThread can be started by WatcherThread::start()
4098 // or by dynamic enrollment.
4099 WatcherThread::make_startable();
4100 // Start up the WatcherThread if there are any periodic tasks
4101 // NOTE: All PeriodicTasks should be registered by now. If they
4102 // aren't, late joiners might appear to start slowly (we might
4103 // take a while to process their first tick).
4104 if (PeriodicTask::num_tasks() > 0) {
4105 WatcherThread::start();
4106 }
4107 }
4108
4109 create_vm_timer.end();
4110 #ifdef ASSERT
4111 _vm_complete = true;
4112 #endif
4113
4114 if (DumpSharedSpaces) {
4115 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
4116 ShouldNotReachHere();
4117 }
4118
4119 return JNI_OK;
4120 }
4121
4122 // type for the Agent_OnLoad and JVM_OnLoad entry points
4123 extern "C" {
4124 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
4125 }
4126 // Find a command line agent library and return its entry point for
4127 // -agentlib: -agentpath: -Xrun
4128 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
4129 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
4130 const char *on_load_symbols[],
4131 size_t num_symbol_entries) {
4132 OnLoadEntry_t on_load_entry = NULL;
4133 void *library = NULL;
4134
4135 if (!agent->valid()) {
4136 char buffer[JVM_MAXPATHLEN];
4137 char ebuf[1024] = "";
4138 const char *name = agent->name();
4139 const char *msg = "Could not find agent library ";
4140
4141 // First check to see if agent is statically linked into executable
4142 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
4143 library = agent->os_lib();
4144 } else if (agent->is_absolute_path()) {
4145 library = os::dll_load(name, ebuf, sizeof ebuf);
4146 if (library == NULL) {
4147 const char *sub_msg = " in absolute path, with error: ";
4148 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4149 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4150 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4151 // If we can't find the agent, exit.
4152 vm_exit_during_initialization(buf, NULL);
4153 FREE_C_HEAP_ARRAY(char, buf);
4154 }
4155 } else {
4156 // Try to load the agent from the standard dll directory
4157 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4158 name)) {
4159 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4160 }
4161 if (library == NULL) { // Try the library path directory.
4162 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4163 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4164 }
4165 if (library == NULL) {
4166 const char *sub_msg = " on the library path, with error: ";
4167 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4168
4169 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4170 strlen(ebuf) + strlen(sub_msg2) + 1;
4171 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4172 if (!agent->is_instrument_lib()) {
4173 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4174 } else {
4175 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4176 }
4177 // If we can't find the agent, exit.
4178 vm_exit_during_initialization(buf, NULL);
4179 FREE_C_HEAP_ARRAY(char, buf);
4180 }
4181 }
4182 }
4183 agent->set_os_lib(library);
4184 agent->set_valid();
4185 }
4186
4187 // Find the OnLoad function.
4188 on_load_entry =
4189 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4190 false,
4191 on_load_symbols,
4192 num_symbol_entries));
4193 return on_load_entry;
4194 }
4195
4196 // Find the JVM_OnLoad entry point
4197 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4198 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4199 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4200 }
4201
4202 // Find the Agent_OnLoad entry point
4203 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4204 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4205 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4206 }
4207
4208 // For backwards compatibility with -Xrun
4209 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4210 // treated like -agentpath:
4211 // Must be called before agent libraries are created
4212 void Threads::convert_vm_init_libraries_to_agents() {
4213 AgentLibrary* agent;
4214 AgentLibrary* next;
4215
4216 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4217 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4218 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4219
4220 // If there is an JVM_OnLoad function it will get called later,
4221 // otherwise see if there is an Agent_OnLoad
4222 if (on_load_entry == NULL) {
4223 on_load_entry = lookup_agent_on_load(agent);
4224 if (on_load_entry != NULL) {
4225 // switch it to the agent list -- so that Agent_OnLoad will be called,
4226 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4227 Arguments::convert_library_to_agent(agent);
4228 } else {
4229 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4230 }
4231 }
4232 }
4233 }
4234
4235 // Create agents for -agentlib: -agentpath: and converted -Xrun
4236 // Invokes Agent_OnLoad
4237 // Called very early -- before JavaThreads exist
4238 void Threads::create_vm_init_agents() {
4239 extern struct JavaVM_ main_vm;
4240 AgentLibrary* agent;
4241
4242 JvmtiExport::enter_onload_phase();
4243
4244 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4245 // CDS dumping does not support native JVMTI agent.
4246 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
4247 if (Arguments::is_dumping_archive()) {
4248 if(!agent->is_instrument_lib()) {
4249 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
4250 } else if (!AllowArchivingWithJavaAgent) {
4251 vm_exit_during_cds_dumping(
4252 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
4253 }
4254 }
4255
4256 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4257
4258 if (on_load_entry != NULL) {
4259 // Invoke the Agent_OnLoad function
4260 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4261 if (err != JNI_OK) {
4262 vm_exit_during_initialization("agent library failed to init", agent->name());
4263 }
4264 } else {
4265 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4266 }
4267 }
4268
4269 JvmtiExport::enter_primordial_phase();
4270 }
4271
4272 extern "C" {
4273 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4274 }
4275
4276 void Threads::shutdown_vm_agents() {
4277 // Send any Agent_OnUnload notifications
4278 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4279 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4280 extern struct JavaVM_ main_vm;
4281 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4282
4283 // Find the Agent_OnUnload function.
4284 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4285 os::find_agent_function(agent,
4286 false,
4287 on_unload_symbols,
4288 num_symbol_entries));
4289
4290 // Invoke the Agent_OnUnload function
4291 if (unload_entry != NULL) {
4292 JavaThread* thread = JavaThread::current();
4293 ThreadToNativeFromVM ttn(thread);
4294 HandleMark hm(thread);
4295 (*unload_entry)(&main_vm);
4296 }
4297 }
4298 }
4299
4300 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4301 // Invokes JVM_OnLoad
4302 void Threads::create_vm_init_libraries() {
4303 extern struct JavaVM_ main_vm;
4304 AgentLibrary* agent;
4305
4306 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4307 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4308
4309 if (on_load_entry != NULL) {
4310 // Invoke the JVM_OnLoad function
4311 JavaThread* thread = JavaThread::current();
4312 ThreadToNativeFromVM ttn(thread);
4313 HandleMark hm(thread);
4314 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4315 if (err != JNI_OK) {
4316 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4317 }
4318 } else {
4319 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4320 }
4321 }
4322 }
4323
4324
4325 // Last thread running calls java.lang.Shutdown.shutdown()
4326 void JavaThread::invoke_shutdown_hooks() {
4327 HandleMark hm(this);
4328
4329 // Link all classes for dynamic CDS dumping before vm exit.
4330 // Same operation is being done in JVM_BeforeHalt for handling the
4331 // case where the application calls System.exit().
4332 if (DynamicDumpSharedSpaces) {
4333 MetaspaceShared::link_and_cleanup_shared_classes(false, this);
4334 }
4335
4336 // We could get here with a pending exception, if so clear it now.
4337 if (this->has_pending_exception()) {
4338 this->clear_pending_exception();
4339 }
4340
4341 EXCEPTION_MARK;
4342 Klass* shutdown_klass =
4343 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4344 THREAD);
4345 if (shutdown_klass != NULL) {
4346 // SystemDictionary::resolve_or_null will return null if there was
4347 // an exception. If we cannot load the Shutdown class, just don't
4348 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4349 // won't be run. Note that if a shutdown hook was registered,
4350 // the Shutdown class would have already been loaded
4351 // (Runtime.addShutdownHook will load it).
4352 JavaValue result(T_VOID);
4353 JavaCalls::call_static(&result,
4354 shutdown_klass,
4355 vmSymbols::shutdown_name(),
4356 vmSymbols::void_method_signature(),
4357 THREAD);
4358 }
4359 CLEAR_PENDING_EXCEPTION;
4360 }
4361
4362 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4363 // the program falls off the end of main(). Another VM exit path is through
4364 // vm_exit() when the program calls System.exit() to return a value or when
4365 // there is a serious error in VM. The two shutdown paths are not exactly
4366 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4367 // and VM_Exit op at VM level.
4368 //
4369 // Shutdown sequence:
4370 // + Shutdown native memory tracking if it is on
4371 // + Wait until we are the last non-daemon thread to execute
4372 // <-- every thing is still working at this moment -->
4373 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4374 // shutdown hooks
4375 // + Call before_exit(), prepare for VM exit
4376 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4377 // currently the only user of this mechanism is File.deleteOnExit())
4378 // > stop StatSampler, watcher thread,
4379 // post thread end and vm death events to JVMTI,
4380 // stop signal thread
4381 // + Call JavaThread::exit(), it will:
4382 // > release JNI handle blocks, remove stack guard pages
4383 // > remove this thread from Threads list
4384 // <-- no more Java code from this thread after this point -->
4385 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4386 // the compiler threads at safepoint
4387 // <-- do not use anything that could get blocked by Safepoint -->
4388 // + Disable tracing at JNI/JVM barriers
4389 // + Set _vm_exited flag for threads that are still running native code
4390 // + Call exit_globals()
4391 // > deletes tty
4392 // > deletes PerfMemory resources
4393 // + Delete this thread
4394 // + Return to caller
4395
4396 bool Threads::destroy_vm() {
4397 JavaThread* thread = JavaThread::current();
4398
4399 #ifdef ASSERT
4400 _vm_complete = false;
4401 #endif
4402 // Wait until we are the last non-daemon thread to execute
4403 { MonitorLocker nu(Threads_lock);
4404 while (Threads::number_of_non_daemon_threads() > 1)
4405 // This wait should make safepoint checks, wait without a timeout,
4406 // and wait as a suspend-equivalent condition.
4407 nu.wait(0, Mutex::_as_suspend_equivalent_flag);
4408 }
4409
4410 EventShutdown e;
4411 if (e.should_commit()) {
4412 e.set_reason("No remaining non-daemon Java threads");
4413 e.commit();
4414 }
4415
4416 // Hang forever on exit if we are reporting an error.
4417 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4418 os::infinite_sleep();
4419 }
4420 os::wait_for_keypress_at_exit();
4421
4422 // run Java level shutdown hooks
4423 thread->invoke_shutdown_hooks();
4424
4425 before_exit(thread);
4426
4427 thread->exit(true);
4428
4429 // Stop VM thread.
4430 {
4431 // 4945125 The vm thread comes to a safepoint during exit.
4432 // GC vm_operations can get caught at the safepoint, and the
4433 // heap is unparseable if they are caught. Grab the Heap_lock
4434 // to prevent this. The GC vm_operations will not be able to
4435 // queue until after the vm thread is dead. After this point,
4436 // we'll never emerge out of the safepoint before the VM exits.
4437
4438 MutexLocker ml(Heap_lock, Mutex::_no_safepoint_check_flag);
4439
4440 VMThread::wait_for_vm_thread_exit();
4441 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4442 VMThread::destroy();
4443 }
4444
4445 // Now, all Java threads are gone except daemon threads. Daemon threads
4446 // running Java code or in VM are stopped by the Safepoint. However,
4447 // daemon threads executing native code are still running. But they
4448 // will be stopped at native=>Java/VM barriers. Note that we can't
4449 // simply kill or suspend them, as it is inherently deadlock-prone.
4450
4451 VM_Exit::set_vm_exited();
4452
4453 // Clean up ideal graph printers after the VMThread has started
4454 // the final safepoint which will block all the Compiler threads.
4455 // Note that this Thread has already logically exited so the
4456 // clean_up() function's use of a JavaThreadIteratorWithHandle
4457 // would be a problem except set_vm_exited() has remembered the
4458 // shutdown thread which is granted a policy exception.
4459 #if defined(COMPILER2) && !defined(PRODUCT)
4460 IdealGraphPrinter::clean_up();
4461 #endif
4462
4463 notify_vm_shutdown();
4464
4465 // exit_globals() will delete tty
4466 exit_globals();
4467
4468 // We are after VM_Exit::set_vm_exited() so we can't call
4469 // thread->smr_delete() or we will block on the Threads_lock.
4470 // Deleting the shutdown thread here is safe because another
4471 // JavaThread cannot have an active ThreadsListHandle for
4472 // this JavaThread.
4473 delete thread;
4474
4475 #if INCLUDE_JVMCI
4476 if (JVMCICounterSize > 0) {
4477 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4478 }
4479 #endif
4480
4481 LogConfiguration::finalize();
4482
4483 return true;
4484 }
4485
4486
4487 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4488 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4489 return is_supported_jni_version(version);
4490 }
4491
4492
4493 jboolean Threads::is_supported_jni_version(jint version) {
4494 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4495 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4496 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4497 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4498 if (version == JNI_VERSION_9) return JNI_TRUE;
4499 if (version == JNI_VERSION_10) return JNI_TRUE;
4500 return JNI_FALSE;
4501 }
4502
4503
4504 void Threads::add(JavaThread* p, bool force_daemon) {
4505 // The threads lock must be owned at this point
4506 assert(Threads_lock->owned_by_self(), "must have threads lock");
4507
4508 BarrierSet::barrier_set()->on_thread_attach(p);
4509
4510 // Once a JavaThread is added to the Threads list, smr_delete() has
4511 // to be used to delete it. Otherwise we can just delete it directly.
4512 p->set_on_thread_list();
4513
4514 _number_of_threads++;
4515 oop threadObj = p->threadObj();
4516 bool daemon = true;
4517 // Bootstrapping problem: threadObj can be null for initial
4518 // JavaThread (or for threads attached via JNI)
4519 if ((!force_daemon) && !is_daemon((threadObj))) {
4520 _number_of_non_daemon_threads++;
4521 daemon = false;
4522 }
4523
4524 ThreadService::add_thread(p, daemon);
4525
4526 // Maintain fast thread list
4527 ThreadsSMRSupport::add_thread(p);
4528
4529 // Possible GC point.
4530 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4531 }
4532
4533 void Threads::remove(JavaThread* p, bool is_daemon) {
4534
4535 // Reclaim the ObjectMonitors from the om_in_use_list and om_free_list of the moribund thread.
4536 ObjectSynchronizer::om_flush(p);
4537
4538 // Extra scope needed for Thread_lock, so we can check
4539 // that we do not remove thread without safepoint code notice
4540 { MonitorLocker ml(Threads_lock);
4541
4542 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4543
4544 // Maintain fast thread list
4545 ThreadsSMRSupport::remove_thread(p);
4546
4547 _number_of_threads--;
4548 if (!is_daemon) {
4549 _number_of_non_daemon_threads--;
4550
4551 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4552 // on destroy_vm will wake up.
4553 if (number_of_non_daemon_threads() == 1) {
4554 ml.notify_all();
4555 }
4556 }
4557 ThreadService::remove_thread(p, is_daemon);
4558
4559 // Make sure that safepoint code disregard this thread. This is needed since
4560 // the thread might mess around with locks after this point. This can cause it
4561 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4562 // of this thread since it is removed from the queue.
4563 p->set_terminated_value();
4564 } // unlock Threads_lock
4565
4566 // Since Events::log uses a lock, we grab it outside the Threads_lock
4567 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4568 }
4569
4570 // Operations on the Threads list for GC. These are not explicitly locked,
4571 // but the garbage collector must provide a safe context for them to run.
4572 // In particular, these things should never be called when the Threads_lock
4573 // is held by some other thread. (Note: the Safepoint abstraction also
4574 // uses the Threads_lock to guarantee this property. It also makes sure that
4575 // all threads gets blocked when exiting or starting).
4576
4577 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4578 ALL_JAVA_THREADS(p) {
4579 p->oops_do(f, cf);
4580 }
4581 VMThread::vm_thread()->oops_do(f, cf);
4582 }
4583
4584 void Threads::change_thread_claim_token() {
4585 if (++_thread_claim_token == 0) {
4586 // On overflow of the token counter, there is a risk of future
4587 // collisions between a new global token value and a stale token
4588 // for a thread, because not all iterations visit all threads.
4589 // (Though it's pretty much a theoretical concern for non-trivial
4590 // token counter sizes.) To deal with the possibility, reset all
4591 // the thread tokens to zero on global token overflow.
4592 struct ResetClaims : public ThreadClosure {
4593 virtual void do_thread(Thread* t) {
4594 t->claim_threads_do(false, 0);
4595 }
4596 } reset_claims;
4597 Threads::threads_do(&reset_claims);
4598 // On overflow, update the global token to non-zero, to
4599 // avoid the special "never claimed" initial thread value.
4600 _thread_claim_token = 1;
4601 }
4602 }
4603
4604 #ifdef ASSERT
4605 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
4606 const uintx token = t->threads_do_token();
4607 assert(token == expected,
4608 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
4609 UINTX_FORMAT, kind, p2i(t), token, expected);
4610 }
4611
4612 void Threads::assert_all_threads_claimed() {
4613 ALL_JAVA_THREADS(p) {
4614 assert_thread_claimed("Thread", p, _thread_claim_token);
4615 }
4616 assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token);
4617 }
4618 #endif // ASSERT
4619
4620 class ParallelOopsDoThreadClosure : public ThreadClosure {
4621 private:
4622 OopClosure* _f;
4623 CodeBlobClosure* _cf;
4624 public:
4625 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4626 void do_thread(Thread* t) {
4627 t->oops_do(_f, _cf);
4628 }
4629 };
4630
4631 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4632 ParallelOopsDoThreadClosure tc(f, cf);
4633 possibly_parallel_threads_do(is_par, &tc);
4634 }
4635
4636 void Threads::nmethods_do(CodeBlobClosure* cf) {
4637 ALL_JAVA_THREADS(p) {
4638 // This is used by the code cache sweeper to mark nmethods that are active
4639 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4640 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4641 if(!p->is_Code_cache_sweeper_thread()) {
4642 p->nmethods_do(cf);
4643 }
4644 }
4645 }
4646
4647 void Threads::metadata_do(MetadataClosure* f) {
4648 ALL_JAVA_THREADS(p) {
4649 p->metadata_do(f);
4650 }
4651 }
4652
4653 class ThreadHandlesClosure : public ThreadClosure {
4654 void (*_f)(Metadata*);
4655 public:
4656 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4657 virtual void do_thread(Thread* thread) {
4658 thread->metadata_handles_do(_f);
4659 }
4660 };
4661
4662 void Threads::metadata_handles_do(void f(Metadata*)) {
4663 // Only walk the Handles in Thread.
4664 ThreadHandlesClosure handles_closure(f);
4665 threads_do(&handles_closure);
4666 }
4667
4668 // Get count Java threads that are waiting to enter the specified monitor.
4669 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4670 int count,
4671 address monitor) {
4672 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4673
4674 int i = 0;
4675 DO_JAVA_THREADS(t_list, p) {
4676 if (!p->can_call_java()) continue;
4677
4678 address pending = (address)p->current_pending_monitor();
4679 if (pending == monitor) { // found a match
4680 if (i < count) result->append(p); // save the first count matches
4681 i++;
4682 }
4683 }
4684
4685 return result;
4686 }
4687
4688
4689 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4690 address owner) {
4691 // NULL owner means not locked so we can skip the search
4692 if (owner == NULL) return NULL;
4693
4694 DO_JAVA_THREADS(t_list, p) {
4695 // first, see if owner is the address of a Java thread
4696 if (owner == (address)p) return p;
4697 }
4698
4699 // Cannot assert on lack of success here since this function may be
4700 // used by code that is trying to report useful problem information
4701 // like deadlock detection.
4702 if (UseHeavyMonitors) return NULL;
4703
4704 // If we didn't find a matching Java thread and we didn't force use of
4705 // heavyweight monitors, then the owner is the stack address of the
4706 // Lock Word in the owning Java thread's stack.
4707 //
4708 JavaThread* the_owner = NULL;
4709 DO_JAVA_THREADS(t_list, q) {
4710 if (q->is_lock_owned(owner)) {
4711 the_owner = q;
4712 break;
4713 }
4714 }
4715
4716 // cannot assert on lack of success here; see above comment
4717 return the_owner;
4718 }
4719
4720 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4721 void Threads::print_on(outputStream* st, bool print_stacks,
4722 bool internal_format, bool print_concurrent_locks,
4723 bool print_extended_info) {
4724 char buf[32];
4725 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4726
4727 st->print_cr("Full thread dump %s (%s %s):",
4728 VM_Version::vm_name(),
4729 VM_Version::vm_release(),
4730 VM_Version::vm_info_string());
4731 st->cr();
4732
4733 #if INCLUDE_SERVICES
4734 // Dump concurrent locks
4735 ConcurrentLocksDump concurrent_locks;
4736 if (print_concurrent_locks) {
4737 concurrent_locks.dump_at_safepoint();
4738 }
4739 #endif // INCLUDE_SERVICES
4740
4741 ThreadsSMRSupport::print_info_on(st);
4742 st->cr();
4743
4744 ALL_JAVA_THREADS(p) {
4745 ResourceMark rm;
4746 p->print_on(st, print_extended_info);
4747 if (print_stacks) {
4748 if (internal_format) {
4749 p->trace_stack();
4750 } else {
4751 p->print_stack_on(st);
4752 }
4753 }
4754 st->cr();
4755 #if INCLUDE_SERVICES
4756 if (print_concurrent_locks) {
4757 concurrent_locks.print_locks_on(p, st);
4758 }
4759 #endif // INCLUDE_SERVICES
4760 }
4761
4762 VMThread::vm_thread()->print_on(st);
4763 st->cr();
4764 Universe::heap()->print_gc_threads_on(st);
4765 WatcherThread* wt = WatcherThread::watcher_thread();
4766 if (wt != NULL) {
4767 wt->print_on(st);
4768 st->cr();
4769 }
4770
4771 st->flush();
4772 }
4773
4774 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4775 int buflen, bool* found_current) {
4776 if (this_thread != NULL) {
4777 bool is_current = (current == this_thread);
4778 *found_current = *found_current || is_current;
4779 st->print("%s", is_current ? "=>" : " ");
4780
4781 st->print(PTR_FORMAT, p2i(this_thread));
4782 st->print(" ");
4783 this_thread->print_on_error(st, buf, buflen);
4784 st->cr();
4785 }
4786 }
4787
4788 class PrintOnErrorClosure : public ThreadClosure {
4789 outputStream* _st;
4790 Thread* _current;
4791 char* _buf;
4792 int _buflen;
4793 bool* _found_current;
4794 public:
4795 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4796 int buflen, bool* found_current) :
4797 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4798
4799 virtual void do_thread(Thread* thread) {
4800 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4801 }
4802 };
4803
4804 // Threads::print_on_error() is called by fatal error handler. It's possible
4805 // that VM is not at safepoint and/or current thread is inside signal handler.
4806 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4807 // memory (even in resource area), it might deadlock the error handler.
4808 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4809 int buflen) {
4810 ThreadsSMRSupport::print_info_on(st);
4811 st->cr();
4812
4813 bool found_current = false;
4814 st->print_cr("Java Threads: ( => current thread )");
4815 ALL_JAVA_THREADS(thread) {
4816 print_on_error(thread, st, current, buf, buflen, &found_current);
4817 }
4818 st->cr();
4819
4820 st->print_cr("Other Threads:");
4821 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4822 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4823
4824 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4825 Universe::heap()->gc_threads_do(&print_closure);
4826
4827 if (!found_current) {
4828 st->cr();
4829 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4830 current->print_on_error(st, buf, buflen);
4831 st->cr();
4832 }
4833 st->cr();
4834
4835 st->print_cr("Threads with active compile tasks:");
4836 print_threads_compiling(st, buf, buflen);
4837 }
4838
4839 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
4840 ALL_JAVA_THREADS(thread) {
4841 if (thread->is_Compiler_thread()) {
4842 CompilerThread* ct = (CompilerThread*) thread;
4843
4844 // Keep task in local variable for NULL check.
4845 // ct->_task might be set to NULL by concurring compiler thread
4846 // because it completed the compilation. The task is never freed,
4847 // though, just returned to a free list.
4848 CompileTask* task = ct->task();
4849 if (task != NULL) {
4850 thread->print_name_on_error(st, buf, buflen);
4851 st->print(" ");
4852 task->print(st, NULL, short_form, true);
4853 }
4854 }
4855 }
4856 }
4857
4858
4859 // Internal SpinLock and Mutex
4860 // Based on ParkEvent
4861
4862 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4863 //
4864 // We employ SpinLocks _only for low-contention, fixed-length
4865 // short-duration critical sections where we're concerned
4866 // about native mutex_t or HotSpot Mutex:: latency.
4867 // The mux construct provides a spin-then-block mutual exclusion
4868 // mechanism.
4869 //
4870 // Testing has shown that contention on the ListLock guarding gFreeList
4871 // is common. If we implement ListLock as a simple SpinLock it's common
4872 // for the JVM to devolve to yielding with little progress. This is true
4873 // despite the fact that the critical sections protected by ListLock are
4874 // extremely short.
4875 //
4876 // TODO-FIXME: ListLock should be of type SpinLock.
4877 // We should make this a 1st-class type, integrated into the lock
4878 // hierarchy as leaf-locks. Critically, the SpinLock structure
4879 // should have sufficient padding to avoid false-sharing and excessive
4880 // cache-coherency traffic.
4881
4882
4883 typedef volatile int SpinLockT;
4884
4885 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4886 if (Atomic::cmpxchg(adr, 0, 1) == 0) {
4887 return; // normal fast-path return
4888 }
4889
4890 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4891 int ctr = 0;
4892 int Yields = 0;
4893 for (;;) {
4894 while (*adr != 0) {
4895 ++ctr;
4896 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4897 if (Yields > 5) {
4898 os::naked_short_sleep(1);
4899 } else {
4900 os::naked_yield();
4901 ++Yields;
4902 }
4903 } else {
4904 SpinPause();
4905 }
4906 }
4907 if (Atomic::cmpxchg(adr, 0, 1) == 0) return;
4908 }
4909 }
4910
4911 void Thread::SpinRelease(volatile int * adr) {
4912 assert(*adr != 0, "invariant");
4913 OrderAccess::fence(); // guarantee at least release consistency.
4914 // Roach-motel semantics.
4915 // It's safe if subsequent LDs and STs float "up" into the critical section,
4916 // but prior LDs and STs within the critical section can't be allowed
4917 // to reorder or float past the ST that releases the lock.
4918 // Loads and stores in the critical section - which appear in program
4919 // order before the store that releases the lock - must also appear
4920 // before the store that releases the lock in memory visibility order.
4921 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4922 // the ST of 0 into the lock-word which releases the lock, so fence
4923 // more than covers this on all platforms.
4924 *adr = 0;
4925 }
4926
4927 // muxAcquire and muxRelease:
4928 //
4929 // * muxAcquire and muxRelease support a single-word lock-word construct.
4930 // The LSB of the word is set IFF the lock is held.
4931 // The remainder of the word points to the head of a singly-linked list
4932 // of threads blocked on the lock.
4933 //
4934 // * The current implementation of muxAcquire-muxRelease uses its own
4935 // dedicated Thread._MuxEvent instance. If we're interested in
4936 // minimizing the peak number of extant ParkEvent instances then
4937 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4938 // as certain invariants were satisfied. Specifically, care would need
4939 // to be taken with regards to consuming unpark() "permits".
4940 // A safe rule of thumb is that a thread would never call muxAcquire()
4941 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4942 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4943 // consume an unpark() permit intended for monitorenter, for instance.
4944 // One way around this would be to widen the restricted-range semaphore
4945 // implemented in park(). Another alternative would be to provide
4946 // multiple instances of the PlatformEvent() for each thread. One
4947 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4948 //
4949 // * Usage:
4950 // -- Only as leaf locks
4951 // -- for short-term locking only as muxAcquire does not perform
4952 // thread state transitions.
4953 //
4954 // Alternatives:
4955 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4956 // but with parking or spin-then-park instead of pure spinning.
4957 // * Use Taura-Oyama-Yonenzawa locks.
4958 // * It's possible to construct a 1-0 lock if we encode the lockword as
4959 // (List,LockByte). Acquire will CAS the full lockword while Release
4960 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4961 // acquiring threads use timers (ParkTimed) to detect and recover from
4962 // the stranding window. Thread/Node structures must be aligned on 256-byte
4963 // boundaries by using placement-new.
4964 // * Augment MCS with advisory back-link fields maintained with CAS().
4965 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4966 // The validity of the backlinks must be ratified before we trust the value.
4967 // If the backlinks are invalid the exiting thread must back-track through the
4968 // the forward links, which are always trustworthy.
4969 // * Add a successor indication. The LockWord is currently encoded as
4970 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4971 // to provide the usual futile-wakeup optimization.
4972 // See RTStt for details.
4973 //
4974
4975
4976 const intptr_t LOCKBIT = 1;
4977
4978 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4979 intptr_t w = Atomic::cmpxchg(Lock, (intptr_t)0, LOCKBIT);
4980 if (w == 0) return;
4981 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) {
4982 return;
4983 }
4984
4985 ParkEvent * const Self = Thread::current()->_MuxEvent;
4986 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4987 for (;;) {
4988 int its = (os::is_MP() ? 100 : 0) + 1;
4989
4990 // Optional spin phase: spin-then-park strategy
4991 while (--its >= 0) {
4992 w = *Lock;
4993 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) {
4994 return;
4995 }
4996 }
4997
4998 Self->reset();
4999 Self->OnList = intptr_t(Lock);
5000 // The following fence() isn't _strictly necessary as the subsequent
5001 // CAS() both serializes execution and ratifies the fetched *Lock value.
5002 OrderAccess::fence();
5003 for (;;) {
5004 w = *Lock;
5005 if ((w & LOCKBIT) == 0) {
5006 if (Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) {
5007 Self->OnList = 0; // hygiene - allows stronger asserts
5008 return;
5009 }
5010 continue; // Interference -- *Lock changed -- Just retry
5011 }
5012 assert(w & LOCKBIT, "invariant");
5013 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
5014 if (Atomic::cmpxchg(Lock, w, intptr_t(Self)|LOCKBIT) == w) break;
5015 }
5016
5017 while (Self->OnList != 0) {
5018 Self->park();
5019 }
5020 }
5021 }
5022
5023 // Release() must extract a successor from the list and then wake that thread.
5024 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
5025 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
5026 // Release() would :
5027 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
5028 // (B) Extract a successor from the private list "in-hand"
5029 // (C) attempt to CAS() the residual back into *Lock over null.
5030 // If there were any newly arrived threads and the CAS() would fail.
5031 // In that case Release() would detach the RATs, re-merge the list in-hand
5032 // with the RATs and repeat as needed. Alternately, Release() might
5033 // detach and extract a successor, but then pass the residual list to the wakee.
5034 // The wakee would be responsible for reattaching and remerging before it
5035 // competed for the lock.
5036 //
5037 // Both "pop" and DMR are immune from ABA corruption -- there can be
5038 // multiple concurrent pushers, but only one popper or detacher.
5039 // This implementation pops from the head of the list. This is unfair,
5040 // but tends to provide excellent throughput as hot threads remain hot.
5041 // (We wake recently run threads first).
5042 //
5043 // All paths through muxRelease() will execute a CAS.
5044 // Release consistency -- We depend on the CAS in muxRelease() to provide full
5045 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
5046 // executed within the critical section are complete and globally visible before the
5047 // store (CAS) to the lock-word that releases the lock becomes globally visible.
5048 void Thread::muxRelease(volatile intptr_t * Lock) {
5049 for (;;) {
5050 const intptr_t w = Atomic::cmpxchg(Lock, LOCKBIT, (intptr_t)0);
5051 assert(w & LOCKBIT, "invariant");
5052 if (w == LOCKBIT) return;
5053 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
5054 assert(List != NULL, "invariant");
5055 assert(List->OnList == intptr_t(Lock), "invariant");
5056 ParkEvent * const nxt = List->ListNext;
5057 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5058
5059 // The following CAS() releases the lock and pops the head element.
5060 // The CAS() also ratifies the previously fetched lock-word value.
5061 if (Atomic::cmpxchg(Lock, w, intptr_t(nxt)) != w) {
5062 continue;
5063 }
5064 List->OnList = 0;
5065 OrderAccess::fence();
5066 List->unpark();
5067 return;
5068 }
5069 }
5070
5071
5072 void Threads::verify() {
5073 ALL_JAVA_THREADS(p) {
5074 p->verify();
5075 }
5076 VMThread* thread = VMThread::vm_thread();
5077 if (thread != NULL) thread->verify();
5078 }