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 // Check for adr in the live portion of our stack.
1022 bool Thread::is_in_stack(address adr) const {
1023 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1024 address end = os::current_stack_pointer();
1025 return (stack_base() > adr && adr >= end);
1026 }
1027
1028 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1029 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1030 // used for compilation in the future. If that change is made, the need for these methods
1031 // should be revisited, and they should be removed if possible.
1032
1033 bool Thread::is_lock_owned(address adr) const {
1034 return on_local_stack(adr);
1035 }
1036
1037 bool Thread::set_as_starting_thread() {
1038 assert(_starting_thread == NULL, "already initialized: "
1039 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
1040 // NOTE: this must be called inside the main thread.
1041 DEBUG_ONLY(_starting_thread = this;)
1042 return os::create_main_thread((JavaThread*)this);
1043 }
1044
1045 static void initialize_class(Symbol* class_name, TRAPS) {
1046 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1047 InstanceKlass::cast(klass)->initialize(CHECK);
1048 }
1049
1050
1051 // Creates the initial ThreadGroup
1052 static Handle create_initial_thread_group(TRAPS) {
1053 Handle system_instance = JavaCalls::construct_new_instance(
1054 SystemDictionary::ThreadGroup_klass(),
1055 vmSymbols::void_method_signature(),
1056 CHECK_NH);
1057 Universe::set_system_thread_group(system_instance());
1058
1059 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1060 Handle main_instance = JavaCalls::construct_new_instance(
1061 SystemDictionary::ThreadGroup_klass(),
1062 vmSymbols::threadgroup_string_void_signature(),
1063 system_instance,
1064 string,
1065 CHECK_NH);
1066 return main_instance;
1067 }
1068
1069 // Creates the initial Thread
1070 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1071 TRAPS) {
1072 InstanceKlass* ik = SystemDictionary::Thread_klass();
1073 assert(ik->is_initialized(), "must be");
1074 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1075
1076 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1077 // constructor calls Thread.current(), which must be set here for the
1078 // initial thread.
1079 java_lang_Thread::set_thread(thread_oop(), thread);
1080 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1081 thread->set_threadObj(thread_oop());
1082
1083 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1084
1085 JavaValue result(T_VOID);
1086 JavaCalls::call_special(&result, thread_oop,
1087 ik,
1088 vmSymbols::object_initializer_name(),
1089 vmSymbols::threadgroup_string_void_signature(),
1090 thread_group,
1091 string,
1092 CHECK_NULL);
1093 return thread_oop();
1094 }
1095
1096 char java_runtime_name[128] = "";
1097 char java_runtime_version[128] = "";
1098 char java_runtime_vendor_version[128] = "";
1099 char java_runtime_vendor_vm_bug_url[128] = "";
1100
1101 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1102 static const char* get_java_runtime_name(TRAPS) {
1103 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1104 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1105 fieldDescriptor fd;
1106 bool found = k != NULL &&
1107 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1108 vmSymbols::string_signature(), &fd);
1109 if (found) {
1110 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1111 if (name_oop == NULL) {
1112 return NULL;
1113 }
1114 const char* name = java_lang_String::as_utf8_string(name_oop,
1115 java_runtime_name,
1116 sizeof(java_runtime_name));
1117 return name;
1118 } else {
1119 return NULL;
1120 }
1121 }
1122
1123 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1124 static const char* get_java_runtime_version(TRAPS) {
1125 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1126 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1127 fieldDescriptor fd;
1128 bool found = k != NULL &&
1129 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1130 vmSymbols::string_signature(), &fd);
1131 if (found) {
1132 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1133 if (name_oop == NULL) {
1134 return NULL;
1135 }
1136 const char* name = java_lang_String::as_utf8_string(name_oop,
1137 java_runtime_version,
1138 sizeof(java_runtime_version));
1139 return name;
1140 } else {
1141 return NULL;
1142 }
1143 }
1144
1145 // extract the JRE vendor version from java.lang.VersionProps.VENDOR_VERSION
1146 static const char* get_java_runtime_vendor_version(TRAPS) {
1147 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1148 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1149 fieldDescriptor fd;
1150 bool found = k != NULL &&
1151 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_vendor_version_name(),
1152 vmSymbols::string_signature(), &fd);
1153 if (found) {
1154 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1155 if (name_oop == NULL) {
1156 return NULL;
1157 }
1158 const char* name = java_lang_String::as_utf8_string(name_oop,
1159 java_runtime_vendor_version,
1160 sizeof(java_runtime_vendor_version));
1161 return name;
1162 } else {
1163 return NULL;
1164 }
1165 }
1166
1167 // extract the JRE vendor VM bug URL from java.lang.VersionProps.VENDOR_URL_VM_BUG
1168 static const char* get_java_runtime_vendor_vm_bug_url(TRAPS) {
1169 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1170 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1171 fieldDescriptor fd;
1172 bool found = k != NULL &&
1173 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_vendor_vm_bug_url_name(),
1174 vmSymbols::string_signature(), &fd);
1175 if (found) {
1176 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1177 if (name_oop == NULL) {
1178 return NULL;
1179 }
1180 const char* name = java_lang_String::as_utf8_string(name_oop,
1181 java_runtime_vendor_vm_bug_url,
1182 sizeof(java_runtime_vendor_vm_bug_url));
1183 return name;
1184 } else {
1185 return NULL;
1186 }
1187 }
1188
1189 // General purpose hook into Java code, run once when the VM is initialized.
1190 // The Java library method itself may be changed independently from the VM.
1191 static void call_postVMInitHook(TRAPS) {
1192 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1193 if (klass != NULL) {
1194 JavaValue result(T_VOID);
1195 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1196 vmSymbols::void_method_signature(),
1197 CHECK);
1198 }
1199 }
1200
1201 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1202 bool daemon, TRAPS) {
1203 assert(thread_group.not_null(), "thread group should be specified");
1204 assert(threadObj() == NULL, "should only create Java thread object once");
1205
1206 InstanceKlass* ik = SystemDictionary::Thread_klass();
1207 assert(ik->is_initialized(), "must be");
1208 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1209
1210 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1211 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1212 // constructor calls Thread.current(), which must be set here.
1213 java_lang_Thread::set_thread(thread_oop(), this);
1214 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1215 set_threadObj(thread_oop());
1216
1217 JavaValue result(T_VOID);
1218 if (thread_name != NULL) {
1219 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1220 // Thread gets assigned specified name and null target
1221 JavaCalls::call_special(&result,
1222 thread_oop,
1223 ik,
1224 vmSymbols::object_initializer_name(),
1225 vmSymbols::threadgroup_string_void_signature(),
1226 thread_group,
1227 name,
1228 THREAD);
1229 } else {
1230 // Thread gets assigned name "Thread-nnn" and null target
1231 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1232 JavaCalls::call_special(&result,
1233 thread_oop,
1234 ik,
1235 vmSymbols::object_initializer_name(),
1236 vmSymbols::threadgroup_runnable_void_signature(),
1237 thread_group,
1238 Handle(),
1239 THREAD);
1240 }
1241
1242
1243 if (daemon) {
1244 java_lang_Thread::set_daemon(thread_oop());
1245 }
1246
1247 if (HAS_PENDING_EXCEPTION) {
1248 return;
1249 }
1250
1251 Klass* group = SystemDictionary::ThreadGroup_klass();
1252 Handle threadObj(THREAD, this->threadObj());
1253
1254 JavaCalls::call_special(&result,
1255 thread_group,
1256 group,
1257 vmSymbols::add_method_name(),
1258 vmSymbols::thread_void_signature(),
1259 threadObj, // Arg 1
1260 THREAD);
1261 }
1262
1263 // List of all NonJavaThreads and safe iteration over that list.
1264
1265 class NonJavaThread::List {
1266 public:
1267 NonJavaThread* volatile _head;
1268 SingleWriterSynchronizer _protect;
1269
1270 List() : _head(NULL), _protect() {}
1271 };
1272
1273 NonJavaThread::List NonJavaThread::_the_list;
1274
1275 NonJavaThread::Iterator::Iterator() :
1276 _protect_enter(_the_list._protect.enter()),
1277 _current(Atomic::load_acquire(&_the_list._head))
1278 {}
1279
1280 NonJavaThread::Iterator::~Iterator() {
1281 _the_list._protect.exit(_protect_enter);
1282 }
1283
1284 void NonJavaThread::Iterator::step() {
1285 assert(!end(), "precondition");
1286 _current = Atomic::load_acquire(&_current->_next);
1287 }
1288
1289 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) {
1290 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!");
1291 }
1292
1293 NonJavaThread::~NonJavaThread() { }
1294
1295 void NonJavaThread::add_to_the_list() {
1296 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1297 // Initialize BarrierSet-related data before adding to list.
1298 BarrierSet::barrier_set()->on_thread_attach(this);
1299 Atomic::release_store(&_next, _the_list._head);
1300 Atomic::release_store(&_the_list._head, this);
1301 }
1302
1303 void NonJavaThread::remove_from_the_list() {
1304 {
1305 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1306 // Cleanup BarrierSet-related data before removing from list.
1307 BarrierSet::barrier_set()->on_thread_detach(this);
1308 NonJavaThread* volatile* p = &_the_list._head;
1309 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) {
1310 if (t == this) {
1311 *p = _next;
1312 break;
1313 }
1314 }
1315 }
1316 // Wait for any in-progress iterators. Concurrent synchronize is not
1317 // allowed, so do it while holding a dedicated lock. Outside and distinct
1318 // from NJTList_lock in case an iteration attempts to lock it.
1319 MutexLocker ml(NonJavaThreadsListSync_lock, Mutex::_no_safepoint_check_flag);
1320 _the_list._protect.synchronize();
1321 _next = NULL; // Safe to drop the link now.
1322 }
1323
1324 void NonJavaThread::pre_run() {
1325 add_to_the_list();
1326
1327 // This is slightly odd in that NamedThread is a subclass, but
1328 // in fact name() is defined in Thread
1329 assert(this->name() != NULL, "thread name was not set before it was started");
1330 this->set_native_thread_name(this->name());
1331 }
1332
1333 void NonJavaThread::post_run() {
1334 JFR_ONLY(Jfr::on_thread_exit(this);)
1335 remove_from_the_list();
1336 // Ensure thread-local-storage is cleared before termination.
1337 Thread::clear_thread_current();
1338 }
1339
1340 // NamedThread -- non-JavaThread subclasses with multiple
1341 // uniquely named instances should derive from this.
1342 NamedThread::NamedThread() :
1343 NonJavaThread(),
1344 _name(NULL),
1345 _processed_thread(NULL),
1346 _gc_id(GCId::undefined())
1347 {}
1348
1349 NamedThread::~NamedThread() {
1350 FREE_C_HEAP_ARRAY(char, _name);
1351 }
1352
1353 void NamedThread::set_name(const char* format, ...) {
1354 guarantee(_name == NULL, "Only get to set name once.");
1355 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1356 va_list ap;
1357 va_start(ap, format);
1358 jio_vsnprintf(_name, max_name_len, format, ap);
1359 va_end(ap);
1360 }
1361
1362 void NamedThread::print_on(outputStream* st) const {
1363 st->print("\"%s\" ", name());
1364 Thread::print_on(st);
1365 st->cr();
1366 }
1367
1368
1369 // ======= WatcherThread ========
1370
1371 // The watcher thread exists to simulate timer interrupts. It should
1372 // be replaced by an abstraction over whatever native support for
1373 // timer interrupts exists on the platform.
1374
1375 WatcherThread* WatcherThread::_watcher_thread = NULL;
1376 bool WatcherThread::_startable = false;
1377 volatile bool WatcherThread::_should_terminate = false;
1378
1379 WatcherThread::WatcherThread() : NonJavaThread() {
1380 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1381 if (os::create_thread(this, os::watcher_thread)) {
1382 _watcher_thread = this;
1383
1384 // Set the watcher thread to the highest OS priority which should not be
1385 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1386 // is created. The only normal thread using this priority is the reference
1387 // handler thread, which runs for very short intervals only.
1388 // If the VMThread's priority is not lower than the WatcherThread profiling
1389 // will be inaccurate.
1390 os::set_priority(this, MaxPriority);
1391 if (!DisableStartThread) {
1392 os::start_thread(this);
1393 }
1394 }
1395 }
1396
1397 int WatcherThread::sleep() const {
1398 // The WatcherThread does not participate in the safepoint protocol
1399 // for the PeriodicTask_lock because it is not a JavaThread.
1400 MonitorLocker ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1401
1402 if (_should_terminate) {
1403 // check for termination before we do any housekeeping or wait
1404 return 0; // we did not sleep.
1405 }
1406
1407 // remaining will be zero if there are no tasks,
1408 // causing the WatcherThread to sleep until a task is
1409 // enrolled
1410 int remaining = PeriodicTask::time_to_wait();
1411 int time_slept = 0;
1412
1413 // we expect this to timeout - we only ever get unparked when
1414 // we should terminate or when a new task has been enrolled
1415 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1416
1417 jlong time_before_loop = os::javaTimeNanos();
1418
1419 while (true) {
1420 bool timedout = ml.wait(remaining);
1421 jlong now = os::javaTimeNanos();
1422
1423 if (remaining == 0) {
1424 // if we didn't have any tasks we could have waited for a long time
1425 // consider the time_slept zero and reset time_before_loop
1426 time_slept = 0;
1427 time_before_loop = now;
1428 } else {
1429 // need to recalculate since we might have new tasks in _tasks
1430 time_slept = (int) ((now - time_before_loop) / 1000000);
1431 }
1432
1433 // Change to task list or spurious wakeup of some kind
1434 if (timedout || _should_terminate) {
1435 break;
1436 }
1437
1438 remaining = PeriodicTask::time_to_wait();
1439 if (remaining == 0) {
1440 // Last task was just disenrolled so loop around and wait until
1441 // another task gets enrolled
1442 continue;
1443 }
1444
1445 remaining -= time_slept;
1446 if (remaining <= 0) {
1447 break;
1448 }
1449 }
1450
1451 return time_slept;
1452 }
1453
1454 void WatcherThread::run() {
1455 assert(this == watcher_thread(), "just checking");
1456
1457 this->set_active_handles(JNIHandleBlock::allocate_block());
1458 while (true) {
1459 assert(watcher_thread() == Thread::current(), "thread consistency check");
1460 assert(watcher_thread() == this, "thread consistency check");
1461
1462 // Calculate how long it'll be until the next PeriodicTask work
1463 // should be done, and sleep that amount of time.
1464 int time_waited = sleep();
1465
1466 if (VMError::is_error_reported()) {
1467 // A fatal error has happened, the error handler(VMError::report_and_die)
1468 // should abort JVM after creating an error log file. However in some
1469 // rare cases, the error handler itself might deadlock. Here periodically
1470 // check for error reporting timeouts, and if it happens, just proceed to
1471 // abort the VM.
1472
1473 // This code is in WatcherThread because WatcherThread wakes up
1474 // periodically so the fatal error handler doesn't need to do anything;
1475 // also because the WatcherThread is less likely to crash than other
1476 // threads.
1477
1478 for (;;) {
1479 // Note: we use naked sleep in this loop because we want to avoid using
1480 // any kind of VM infrastructure which may be broken at this point.
1481 if (VMError::check_timeout()) {
1482 // We hit error reporting timeout. Error reporting was interrupted and
1483 // will be wrapping things up now (closing files etc). Give it some more
1484 // time, then quit the VM.
1485 os::naked_short_sleep(200);
1486 // Print a message to stderr.
1487 fdStream err(defaultStream::output_fd());
1488 err.print_raw_cr("# [ timer expired, abort... ]");
1489 // skip atexit/vm_exit/vm_abort hooks
1490 os::die();
1491 }
1492
1493 // Wait a second, then recheck for timeout.
1494 os::naked_short_sleep(999);
1495 }
1496 }
1497
1498 if (_should_terminate) {
1499 // check for termination before posting the next tick
1500 break;
1501 }
1502
1503 PeriodicTask::real_time_tick(time_waited);
1504 }
1505
1506 // Signal that it is terminated
1507 {
1508 MutexLocker mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1509 _watcher_thread = NULL;
1510 Terminator_lock->notify_all();
1511 }
1512 }
1513
1514 void WatcherThread::start() {
1515 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1516
1517 if (watcher_thread() == NULL && _startable) {
1518 _should_terminate = false;
1519 // Create the single instance of WatcherThread
1520 new WatcherThread();
1521 }
1522 }
1523
1524 void WatcherThread::make_startable() {
1525 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1526 _startable = true;
1527 }
1528
1529 void WatcherThread::stop() {
1530 {
1531 // Follow normal safepoint aware lock enter protocol since the
1532 // WatcherThread is stopped by another JavaThread.
1533 MutexLocker ml(PeriodicTask_lock);
1534 _should_terminate = true;
1535
1536 WatcherThread* watcher = watcher_thread();
1537 if (watcher != NULL) {
1538 // unpark the WatcherThread so it can see that it should terminate
1539 watcher->unpark();
1540 }
1541 }
1542
1543 MonitorLocker mu(Terminator_lock);
1544
1545 while (watcher_thread() != NULL) {
1546 // This wait should make safepoint checks, wait without a timeout,
1547 // and wait as a suspend-equivalent condition.
1548 mu.wait(0, Mutex::_as_suspend_equivalent_flag);
1549 }
1550 }
1551
1552 void WatcherThread::unpark() {
1553 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1554 PeriodicTask_lock->notify();
1555 }
1556
1557 void WatcherThread::print_on(outputStream* st) const {
1558 st->print("\"%s\" ", name());
1559 Thread::print_on(st);
1560 st->cr();
1561 }
1562
1563 // ======= JavaThread ========
1564
1565 #if INCLUDE_JVMCI
1566
1567 jlong* JavaThread::_jvmci_old_thread_counters;
1568
1569 bool jvmci_counters_include(JavaThread* thread) {
1570 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1571 }
1572
1573 void JavaThread::collect_counters(jlong* array, int length) {
1574 assert(length == JVMCICounterSize, "wrong value");
1575 for (int i = 0; i < length; i++) {
1576 array[i] = _jvmci_old_thread_counters[i];
1577 }
1578 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
1579 if (jvmci_counters_include(tp)) {
1580 for (int i = 0; i < length; i++) {
1581 array[i] += tp->_jvmci_counters[i];
1582 }
1583 }
1584 }
1585 }
1586
1587 // Attempt to enlarge the array for per thread counters.
1588 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
1589 jlong* new_counters = NEW_C_HEAP_ARRAY(jlong, new_size, mtJVMCI);
1590 if (old_counters == NULL) {
1591 old_counters = new_counters;
1592 memset(old_counters, 0, sizeof(jlong) * new_size);
1593 } else {
1594 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
1595 new_counters[i] = old_counters[i];
1596 }
1597 if (new_size > current_size) {
1598 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
1599 }
1600 FREE_C_HEAP_ARRAY(jlong, old_counters);
1601 }
1602 return new_counters;
1603 }
1604
1605 // Attempt to enlarge the array for per thread counters.
1606 void JavaThread::resize_counters(int current_size, int new_size) {
1607 _jvmci_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
1608 }
1609
1610 class VM_JVMCIResizeCounters : public VM_Operation {
1611 private:
1612 int _new_size;
1613
1614 public:
1615 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size) { }
1616 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
1617 bool allow_nested_vm_operations() const { return true; }
1618 void doit() {
1619 // Resize the old thread counters array
1620 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
1621 JavaThread::_jvmci_old_thread_counters = new_counters;
1622
1623 // Now resize each threads array
1624 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
1625 tp->resize_counters(JVMCICounterSize, _new_size);
1626 }
1627 JVMCICounterSize = _new_size;
1628 }
1629 };
1630
1631 void JavaThread::resize_all_jvmci_counters(int new_size) {
1632 VM_JVMCIResizeCounters op(new_size);
1633 VMThread::execute(&op);
1634 }
1635
1636 #endif // INCLUDE_JVMCI
1637
1638 // A JavaThread is a normal Java thread
1639
1640 void JavaThread::initialize() {
1641 // Initialize fields
1642
1643 set_saved_exception_pc(NULL);
1644 set_threadObj(NULL);
1645 _anchor.clear();
1646 set_entry_point(NULL);
1647 set_jni_functions(jni_functions());
1648 set_callee_target(NULL);
1649 set_vm_result(NULL);
1650 set_vm_result_2(NULL);
1651 set_vframe_array_head(NULL);
1652 set_vframe_array_last(NULL);
1653 set_deferred_locals(NULL);
1654 set_deopt_mark(NULL);
1655 set_deopt_compiled_method(NULL);
1656 set_monitor_chunks(NULL);
1657 _on_thread_list = false;
1658 _thread_state = _thread_new;
1659 _terminated = _not_terminated;
1660 _array_for_gc = NULL;
1661 _suspend_equivalent = false;
1662 _in_deopt_handler = 0;
1663 _doing_unsafe_access = false;
1664 _stack_guard_state = stack_guard_unused;
1665 #if INCLUDE_JVMCI
1666 _pending_monitorenter = false;
1667 _pending_deoptimization = -1;
1668 _pending_failed_speculation = 0;
1669 _pending_transfer_to_interpreter = false;
1670 _in_retryable_allocation = false;
1671 _jvmci._alternate_call_target = NULL;
1672 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1673 _jvmci_counters = NULL;
1674 if (JVMCICounterSize > 0) {
1675 resize_counters(0, (int) JVMCICounterSize);
1676 }
1677 #endif // INCLUDE_JVMCI
1678 _reserved_stack_activation = NULL; // stack base not known yet
1679 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1680 _exception_pc = 0;
1681 _exception_handler_pc = 0;
1682 _is_method_handle_return = 0;
1683 _jvmti_thread_state= NULL;
1684 _should_post_on_exceptions_flag = JNI_FALSE;
1685 _interp_only_mode = 0;
1686 _special_runtime_exit_condition = _no_async_condition;
1687 _pending_async_exception = NULL;
1688 _thread_stat = NULL;
1689 _thread_stat = new ThreadStatistics();
1690 _jni_active_critical = 0;
1691 _pending_jni_exception_check_fn = NULL;
1692 _do_not_unlock_if_synchronized = false;
1693 _cached_monitor_info = NULL;
1694 _parker = Parker::Allocate(this);
1695 _SleepEvent = ParkEvent::Allocate(this);
1696 // Setup safepoint state info for this thread
1697 ThreadSafepointState::create(this);
1698
1699 debug_only(_java_call_counter = 0);
1700
1701 // JVMTI PopFrame support
1702 _popframe_condition = popframe_inactive;
1703 _popframe_preserved_args = NULL;
1704 _popframe_preserved_args_size = 0;
1705 _frames_to_pop_failed_realloc = 0;
1706
1707 if (SafepointMechanism::uses_thread_local_poll()) {
1708 SafepointMechanism::initialize_header(this);
1709 }
1710
1711 _class_to_be_initialized = NULL;
1712
1713 pd_initialize();
1714 }
1715
1716 JavaThread::JavaThread(bool is_attaching_via_jni) :
1717 Thread() {
1718 initialize();
1719 if (is_attaching_via_jni) {
1720 _jni_attach_state = _attaching_via_jni;
1721 } else {
1722 _jni_attach_state = _not_attaching_via_jni;
1723 }
1724 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1725 }
1726
1727
1728 // interrupt support
1729
1730 void JavaThread::interrupt() {
1731 debug_only(check_for_dangling_thread_pointer(this);)
1732
1733 // For Windows _interrupt_event
1734 osthread()->set_interrupted(true);
1735
1736 // For Thread.sleep
1737 _SleepEvent->unpark();
1738
1739 // For JSR166 LockSupport.park
1740 parker()->unpark();
1741
1742 // For ObjectMonitor and JvmtiRawMonitor
1743 _ParkEvent->unpark();
1744 }
1745
1746
1747 bool JavaThread::is_interrupted(bool clear_interrupted) {
1748 debug_only(check_for_dangling_thread_pointer(this);)
1749
1750 if (threadObj() == NULL) {
1751 // If there is no j.l.Thread then it is impossible to have
1752 // been interrupted. We can find NULL during VM initialization
1753 // or when a JNI thread is still in the process of attaching.
1754 // In such cases this must be the current thread.
1755 assert(this == Thread::current(), "invariant");
1756 return false;
1757 }
1758
1759 bool interrupted = java_lang_Thread::interrupted(threadObj());
1760
1761 // NOTE that since there is no "lock" around the interrupt and
1762 // is_interrupted operations, there is the possibility that the
1763 // interrupted flag will be "false" but that the
1764 // low-level events will be in the signaled state. This is
1765 // intentional. The effect of this is that Object.wait() and
1766 // LockSupport.park() will appear to have a spurious wakeup, which
1767 // is allowed and not harmful, and the possibility is so rare that
1768 // it is not worth the added complexity to add yet another lock.
1769 // For the sleep event an explicit reset is performed on entry
1770 // to JavaThread::sleep, so there is no early return. It has also been
1771 // recommended not to put the interrupted flag into the "event"
1772 // structure because it hides the issue.
1773 // Also, because there is no lock, we must only clear the interrupt
1774 // state if we are going to report that we were interrupted; otherwise
1775 // an interrupt that happens just after we read the field would be lost.
1776 if (interrupted && clear_interrupted) {
1777 assert(this == Thread::current(), "only the current thread can clear");
1778 java_lang_Thread::set_interrupted(threadObj(), false);
1779 osthread()->set_interrupted(false);
1780 }
1781
1782 return interrupted;
1783 }
1784
1785 bool JavaThread::reguard_stack(address cur_sp) {
1786 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1787 && _stack_guard_state != stack_guard_reserved_disabled) {
1788 return true; // Stack already guarded or guard pages not needed.
1789 }
1790
1791 if (register_stack_overflow()) {
1792 // For those architectures which have separate register and
1793 // memory stacks, we must check the register stack to see if
1794 // it has overflowed.
1795 return false;
1796 }
1797
1798 // Java code never executes within the yellow zone: the latter is only
1799 // there to provoke an exception during stack banging. If java code
1800 // is executing there, either StackShadowPages should be larger, or
1801 // some exception code in c1, c2 or the interpreter isn't unwinding
1802 // when it should.
1803 guarantee(cur_sp > stack_reserved_zone_base(),
1804 "not enough space to reguard - increase StackShadowPages");
1805 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1806 enable_stack_yellow_reserved_zone();
1807 if (reserved_stack_activation() != stack_base()) {
1808 set_reserved_stack_activation(stack_base());
1809 }
1810 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1811 set_reserved_stack_activation(stack_base());
1812 enable_stack_reserved_zone();
1813 }
1814 return true;
1815 }
1816
1817 bool JavaThread::reguard_stack(void) {
1818 return reguard_stack(os::current_stack_pointer());
1819 }
1820
1821
1822 // Check for adr in the usable portion of this thread's stack.
1823 bool JavaThread::is_in_usable_stack(address adr) const {
1824 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1825 size_t usable_stack_size = _stack_size - stack_guard_size;
1826
1827 return ((stack_base() > adr) && (adr >= (stack_base() - usable_stack_size)));
1828 }
1829
1830 void JavaThread::block_if_vm_exited() {
1831 if (_terminated == _vm_exited) {
1832 // _vm_exited is set at safepoint, and Threads_lock is never released
1833 // we will block here forever.
1834 // Here we can be doing a jump from a safe state to an unsafe state without
1835 // proper transition, but it happens after the final safepoint has begun.
1836 set_thread_state(_thread_in_vm);
1837 Threads_lock->lock();
1838 ShouldNotReachHere();
1839 }
1840 }
1841
1842
1843 // Remove this ifdef when C1 is ported to the compiler interface.
1844 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1845 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1846
1847 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1848 Thread() {
1849 initialize();
1850 _jni_attach_state = _not_attaching_via_jni;
1851 set_entry_point(entry_point);
1852 // Create the native thread itself.
1853 // %note runtime_23
1854 os::ThreadType thr_type = os::java_thread;
1855 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1856 os::java_thread;
1857 os::create_thread(this, thr_type, stack_sz);
1858 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1859 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1860 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1861 // the exception consists of creating the exception object & initializing it, initialization
1862 // will leave the VM via a JavaCall and then all locks must be unlocked).
1863 //
1864 // The thread is still suspended when we reach here. Thread must be explicit started
1865 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1866 // by calling Threads:add. The reason why this is not done here, is because the thread
1867 // object must be fully initialized (take a look at JVM_Start)
1868 }
1869
1870 JavaThread::~JavaThread() {
1871
1872 // JSR166 -- return the parker to the free list
1873 Parker::Release(_parker);
1874 _parker = NULL;
1875
1876 // Return the sleep event to the free list
1877 ParkEvent::Release(_SleepEvent);
1878 _SleepEvent = NULL;
1879
1880 // Free any remaining previous UnrollBlock
1881 vframeArray* old_array = vframe_array_last();
1882
1883 if (old_array != NULL) {
1884 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1885 old_array->set_unroll_block(NULL);
1886 delete old_info;
1887 delete old_array;
1888 }
1889
1890 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1891 if (deferred != NULL) {
1892 // This can only happen if thread is destroyed before deoptimization occurs.
1893 assert(deferred->length() != 0, "empty array!");
1894 do {
1895 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1896 deferred->remove_at(0);
1897 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1898 delete dlv;
1899 } while (deferred->length() != 0);
1900 delete deferred;
1901 }
1902
1903 // All Java related clean up happens in exit
1904 ThreadSafepointState::destroy(this);
1905 if (_thread_stat != NULL) delete _thread_stat;
1906
1907 #if INCLUDE_JVMCI
1908 if (JVMCICounterSize > 0) {
1909 if (jvmci_counters_include(this)) {
1910 for (int i = 0; i < JVMCICounterSize; i++) {
1911 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1912 }
1913 }
1914 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1915 }
1916 #endif // INCLUDE_JVMCI
1917 }
1918
1919
1920 // First JavaThread specific code executed by a new Java thread.
1921 void JavaThread::pre_run() {
1922 // empty - see comments in run()
1923 }
1924
1925 // The main routine called by a new Java thread. This isn't overridden
1926 // by subclasses, instead different subclasses define a different "entry_point"
1927 // which defines the actual logic for that kind of thread.
1928 void JavaThread::run() {
1929 // initialize thread-local alloc buffer related fields
1930 this->initialize_tlab();
1931
1932 // Used to test validity of stack trace backs.
1933 // This can't be moved into pre_run() else we invalidate
1934 // the requirement that thread_main_inner is lower on
1935 // the stack. Consequently all the initialization logic
1936 // stays here in run() rather than pre_run().
1937 this->record_base_of_stack_pointer();
1938
1939 this->create_stack_guard_pages();
1940
1941 this->cache_global_variables();
1942
1943 // Thread is now sufficiently initialized to be handled by the safepoint code as being
1944 // in the VM. Change thread state from _thread_new to _thread_in_vm
1945 ThreadStateTransition::transition(this, _thread_new, _thread_in_vm);
1946 // Before a thread is on the threads list it is always safe, so after leaving the
1947 // _thread_new we should emit a instruction barrier. The distance to modified code
1948 // from here is probably far enough, but this is consistent and safe.
1949 OrderAccess::cross_modify_fence();
1950
1951 assert(JavaThread::current() == this, "sanity check");
1952 assert(!Thread::current()->owns_locks(), "sanity check");
1953
1954 DTRACE_THREAD_PROBE(start, this);
1955
1956 // This operation might block. We call that after all safepoint checks for a new thread has
1957 // been completed.
1958 this->set_active_handles(JNIHandleBlock::allocate_block());
1959
1960 if (JvmtiExport::should_post_thread_life()) {
1961 JvmtiExport::post_thread_start(this);
1962
1963 }
1964
1965 // We call another function to do the rest so we are sure that the stack addresses used
1966 // from there will be lower than the stack base just computed.
1967 thread_main_inner();
1968 }
1969
1970 void JavaThread::thread_main_inner() {
1971 assert(JavaThread::current() == this, "sanity check");
1972 assert(this->threadObj() != NULL, "just checking");
1973
1974 // Execute thread entry point unless this thread has a pending exception
1975 // or has been stopped before starting.
1976 // Note: Due to JVM_StopThread we can have pending exceptions already!
1977 if (!this->has_pending_exception() &&
1978 !java_lang_Thread::is_stillborn(this->threadObj())) {
1979 {
1980 ResourceMark rm(this);
1981 this->set_native_thread_name(this->get_thread_name());
1982 }
1983 HandleMark hm(this);
1984 this->entry_point()(this, this);
1985 }
1986
1987 DTRACE_THREAD_PROBE(stop, this);
1988
1989 // Cleanup is handled in post_run()
1990 }
1991
1992 // Shared teardown for all JavaThreads
1993 void JavaThread::post_run() {
1994 this->exit(false);
1995 // Defer deletion to here to ensure 'this' is still referenceable in call_run
1996 // for any shared tear-down.
1997 this->smr_delete();
1998 }
1999
2000 static void ensure_join(JavaThread* thread) {
2001 // We do not need to grab the Threads_lock, since we are operating on ourself.
2002 Handle threadObj(thread, thread->threadObj());
2003 assert(threadObj.not_null(), "java thread object must exist");
2004 ObjectLocker lock(threadObj, thread);
2005 // Ignore pending exception (ThreadDeath), since we are exiting anyway
2006 thread->clear_pending_exception();
2007 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
2008 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
2009 // Clear the native thread instance - this makes isAlive return false and allows the join()
2010 // to complete once we've done the notify_all below
2011 java_lang_Thread::set_thread(threadObj(), NULL);
2012 lock.notify_all(thread);
2013 // Ignore pending exception (ThreadDeath), since we are exiting anyway
2014 thread->clear_pending_exception();
2015 }
2016
2017 static bool is_daemon(oop threadObj) {
2018 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
2019 }
2020
2021 // For any new cleanup additions, please check to see if they need to be applied to
2022 // cleanup_failed_attach_current_thread as well.
2023 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
2024 assert(this == JavaThread::current(), "thread consistency check");
2025
2026 elapsedTimer _timer_exit_phase1;
2027 elapsedTimer _timer_exit_phase2;
2028 elapsedTimer _timer_exit_phase3;
2029 elapsedTimer _timer_exit_phase4;
2030
2031 if (log_is_enabled(Debug, os, thread, timer)) {
2032 _timer_exit_phase1.start();
2033 }
2034
2035 HandleMark hm(this);
2036 Handle uncaught_exception(this, this->pending_exception());
2037 this->clear_pending_exception();
2038 Handle threadObj(this, this->threadObj());
2039 assert(threadObj.not_null(), "Java thread object should be created");
2040
2041 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
2042 {
2043 EXCEPTION_MARK;
2044
2045 CLEAR_PENDING_EXCEPTION;
2046 }
2047 if (!destroy_vm) {
2048 if (uncaught_exception.not_null()) {
2049 EXCEPTION_MARK;
2050 // Call method Thread.dispatchUncaughtException().
2051 Klass* thread_klass = SystemDictionary::Thread_klass();
2052 JavaValue result(T_VOID);
2053 JavaCalls::call_virtual(&result,
2054 threadObj, thread_klass,
2055 vmSymbols::dispatchUncaughtException_name(),
2056 vmSymbols::throwable_void_signature(),
2057 uncaught_exception,
2058 THREAD);
2059 if (HAS_PENDING_EXCEPTION) {
2060 ResourceMark rm(this);
2061 jio_fprintf(defaultStream::error_stream(),
2062 "\nException: %s thrown from the UncaughtExceptionHandler"
2063 " in thread \"%s\"\n",
2064 pending_exception()->klass()->external_name(),
2065 get_thread_name());
2066 CLEAR_PENDING_EXCEPTION;
2067 }
2068 }
2069 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
2070
2071 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
2072 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
2073 // is deprecated anyhow.
2074 if (!is_Compiler_thread()) {
2075 int count = 3;
2076 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
2077 EXCEPTION_MARK;
2078 JavaValue result(T_VOID);
2079 Klass* thread_klass = SystemDictionary::Thread_klass();
2080 JavaCalls::call_virtual(&result,
2081 threadObj, thread_klass,
2082 vmSymbols::exit_method_name(),
2083 vmSymbols::void_method_signature(),
2084 THREAD);
2085 CLEAR_PENDING_EXCEPTION;
2086 }
2087 }
2088 // notify JVMTI
2089 if (JvmtiExport::should_post_thread_life()) {
2090 JvmtiExport::post_thread_end(this);
2091 }
2092
2093 // We have notified the agents that we are exiting, before we go on,
2094 // we must check for a pending external suspend request and honor it
2095 // in order to not surprise the thread that made the suspend request.
2096 while (true) {
2097 {
2098 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2099 if (!is_external_suspend()) {
2100 set_terminated(_thread_exiting);
2101 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
2102 break;
2103 }
2104 // Implied else:
2105 // Things get a little tricky here. We have a pending external
2106 // suspend request, but we are holding the SR_lock so we
2107 // can't just self-suspend. So we temporarily drop the lock
2108 // and then self-suspend.
2109 }
2110
2111 ThreadBlockInVM tbivm(this);
2112 java_suspend_self();
2113
2114 // We're done with this suspend request, but we have to loop around
2115 // and check again. Eventually we will get SR_lock without a pending
2116 // external suspend request and will be able to mark ourselves as
2117 // exiting.
2118 }
2119 // no more external suspends are allowed at this point
2120 } else {
2121 assert(!is_terminated() && !is_exiting(), "must not be exiting");
2122 // before_exit() has already posted JVMTI THREAD_END events
2123 }
2124
2125 if (log_is_enabled(Debug, os, thread, timer)) {
2126 _timer_exit_phase1.stop();
2127 _timer_exit_phase2.start();
2128 }
2129
2130 // Capture daemon status before the thread is marked as terminated.
2131 bool daemon = is_daemon(threadObj());
2132
2133 // Notify waiters on thread object. This has to be done after exit() is called
2134 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
2135 // group should have the destroyed bit set before waiters are notified).
2136 ensure_join(this);
2137 assert(!this->has_pending_exception(), "ensure_join should have cleared");
2138
2139 if (log_is_enabled(Debug, os, thread, timer)) {
2140 _timer_exit_phase2.stop();
2141 _timer_exit_phase3.start();
2142 }
2143 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
2144 // held by this thread must be released. The spec does not distinguish
2145 // between JNI-acquired and regular Java monitors. We can only see
2146 // regular Java monitors here if monitor enter-exit matching is broken.
2147 //
2148 // ensure_join() ignores IllegalThreadStateExceptions, and so does
2149 // ObjectSynchronizer::release_monitors_owned_by_thread().
2150 if (exit_type == jni_detach) {
2151 // Sanity check even though JNI DetachCurrentThread() would have
2152 // returned JNI_ERR if there was a Java frame. JavaThread exit
2153 // should be done executing Java code by the time we get here.
2154 assert(!this->has_last_Java_frame(),
2155 "should not have a Java frame when detaching or exiting");
2156 ObjectSynchronizer::release_monitors_owned_by_thread(this);
2157 assert(!this->has_pending_exception(), "release_monitors should have cleared");
2158 }
2159
2160 // These things needs to be done while we are still a Java Thread. Make sure that thread
2161 // is in a consistent state, in case GC happens
2162 JFR_ONLY(Jfr::on_thread_exit(this);)
2163
2164 if (active_handles() != NULL) {
2165 JNIHandleBlock* block = active_handles();
2166 set_active_handles(NULL);
2167 JNIHandleBlock::release_block(block);
2168 }
2169
2170 if (free_handle_block() != NULL) {
2171 JNIHandleBlock* block = free_handle_block();
2172 set_free_handle_block(NULL);
2173 JNIHandleBlock::release_block(block);
2174 }
2175
2176 // These have to be removed while this is still a valid thread.
2177 remove_stack_guard_pages();
2178
2179 if (UseTLAB) {
2180 tlab().retire();
2181 }
2182
2183 if (JvmtiEnv::environments_might_exist()) {
2184 JvmtiExport::cleanup_thread(this);
2185 }
2186
2187 // We must flush any deferred card marks and other various GC barrier
2188 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2189 // before removing a thread from the list of active threads.
2190 BarrierSet::barrier_set()->on_thread_detach(this);
2191
2192 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2193 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2194 os::current_thread_id());
2195
2196 if (log_is_enabled(Debug, os, thread, timer)) {
2197 _timer_exit_phase3.stop();
2198 _timer_exit_phase4.start();
2199 }
2200 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2201 Threads::remove(this, daemon);
2202
2203 if (log_is_enabled(Debug, os, thread, timer)) {
2204 _timer_exit_phase4.stop();
2205 ResourceMark rm(this);
2206 log_debug(os, thread, timer)("name='%s'"
2207 ", exit-phase1=" JLONG_FORMAT
2208 ", exit-phase2=" JLONG_FORMAT
2209 ", exit-phase3=" JLONG_FORMAT
2210 ", exit-phase4=" JLONG_FORMAT,
2211 get_thread_name(),
2212 _timer_exit_phase1.milliseconds(),
2213 _timer_exit_phase2.milliseconds(),
2214 _timer_exit_phase3.milliseconds(),
2215 _timer_exit_phase4.milliseconds());
2216 }
2217 }
2218
2219 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
2220 if (active_handles() != NULL) {
2221 JNIHandleBlock* block = active_handles();
2222 set_active_handles(NULL);
2223 JNIHandleBlock::release_block(block);
2224 }
2225
2226 if (free_handle_block() != NULL) {
2227 JNIHandleBlock* block = free_handle_block();
2228 set_free_handle_block(NULL);
2229 JNIHandleBlock::release_block(block);
2230 }
2231
2232 // These have to be removed while this is still a valid thread.
2233 remove_stack_guard_pages();
2234
2235 if (UseTLAB) {
2236 tlab().retire();
2237 }
2238
2239 BarrierSet::barrier_set()->on_thread_detach(this);
2240
2241 Threads::remove(this, is_daemon);
2242 this->smr_delete();
2243 }
2244
2245 JavaThread* JavaThread::active() {
2246 Thread* thread = Thread::current();
2247 if (thread->is_Java_thread()) {
2248 return (JavaThread*) thread;
2249 } else {
2250 assert(thread->is_VM_thread(), "this must be a vm thread");
2251 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2252 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2253 assert(ret->is_Java_thread(), "must be a Java thread");
2254 return ret;
2255 }
2256 }
2257
2258 bool JavaThread::is_lock_owned(address adr) const {
2259 if (Thread::is_lock_owned(adr)) return true;
2260
2261 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2262 if (chunk->contains(adr)) return true;
2263 }
2264
2265 return false;
2266 }
2267
2268
2269 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2270 chunk->set_next(monitor_chunks());
2271 set_monitor_chunks(chunk);
2272 }
2273
2274 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2275 guarantee(monitor_chunks() != NULL, "must be non empty");
2276 if (monitor_chunks() == chunk) {
2277 set_monitor_chunks(chunk->next());
2278 } else {
2279 MonitorChunk* prev = monitor_chunks();
2280 while (prev->next() != chunk) prev = prev->next();
2281 prev->set_next(chunk->next());
2282 }
2283 }
2284
2285 // JVM support.
2286
2287 // Note: this function shouldn't block if it's called in
2288 // _thread_in_native_trans state (such as from
2289 // check_special_condition_for_native_trans()).
2290 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2291
2292 if (has_last_Java_frame() && has_async_condition()) {
2293 // If we are at a polling page safepoint (not a poll return)
2294 // then we must defer async exception because live registers
2295 // will be clobbered by the exception path. Poll return is
2296 // ok because the call we a returning from already collides
2297 // with exception handling registers and so there is no issue.
2298 // (The exception handling path kills call result registers but
2299 // this is ok since the exception kills the result anyway).
2300
2301 if (is_at_poll_safepoint()) {
2302 // if the code we are returning to has deoptimized we must defer
2303 // the exception otherwise live registers get clobbered on the
2304 // exception path before deoptimization is able to retrieve them.
2305 //
2306 RegisterMap map(this, false);
2307 frame caller_fr = last_frame().sender(&map);
2308 assert(caller_fr.is_compiled_frame(), "what?");
2309 if (caller_fr.is_deoptimized_frame()) {
2310 log_info(exceptions)("deferred async exception at compiled safepoint");
2311 return;
2312 }
2313 }
2314 }
2315
2316 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2317 if (condition == _no_async_condition) {
2318 // Conditions have changed since has_special_runtime_exit_condition()
2319 // was called:
2320 // - if we were here only because of an external suspend request,
2321 // then that was taken care of above (or cancelled) so we are done
2322 // - if we were here because of another async request, then it has
2323 // been cleared between the has_special_runtime_exit_condition()
2324 // and now so again we are done
2325 return;
2326 }
2327
2328 // Check for pending async. exception
2329 if (_pending_async_exception != NULL) {
2330 // Only overwrite an already pending exception, if it is not a threadDeath.
2331 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2332
2333 // We cannot call Exceptions::_throw(...) here because we cannot block
2334 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2335
2336 LogTarget(Info, exceptions) lt;
2337 if (lt.is_enabled()) {
2338 ResourceMark rm;
2339 LogStream ls(lt);
2340 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2341 if (has_last_Java_frame()) {
2342 frame f = last_frame();
2343 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2344 }
2345 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2346 }
2347 _pending_async_exception = NULL;
2348 clear_has_async_exception();
2349 }
2350 }
2351
2352 if (check_unsafe_error &&
2353 condition == _async_unsafe_access_error && !has_pending_exception()) {
2354 condition = _no_async_condition; // done
2355 switch (thread_state()) {
2356 case _thread_in_vm: {
2357 JavaThread* THREAD = this;
2358 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2359 }
2360 case _thread_in_native: {
2361 ThreadInVMfromNative tiv(this);
2362 JavaThread* THREAD = this;
2363 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2364 }
2365 case _thread_in_Java: {
2366 ThreadInVMfromJava tiv(this);
2367 JavaThread* THREAD = this;
2368 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2369 }
2370 default:
2371 ShouldNotReachHere();
2372 }
2373 }
2374
2375 assert(condition == _no_async_condition || has_pending_exception() ||
2376 (!check_unsafe_error && condition == _async_unsafe_access_error),
2377 "must have handled the async condition, if no exception");
2378 }
2379
2380 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2381
2382 // Check for pending external suspend.
2383 if (is_external_suspend_with_lock()) {
2384 frame_anchor()->make_walkable(this);
2385 java_suspend_self_with_safepoint_check();
2386 }
2387
2388 // We might be here for reasons in addition to the self-suspend request
2389 // so check for other async requests.
2390 if (check_asyncs) {
2391 check_and_handle_async_exceptions();
2392 }
2393
2394 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2395 }
2396
2397 void JavaThread::send_thread_stop(oop java_throwable) {
2398 ResourceMark rm;
2399 assert(Thread::current()->is_VM_thread() || Thread::current() == this, "should be in the vm thread");
2400
2401 // Do not throw asynchronous exceptions against the compiler thread
2402 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2403 if (!can_call_java()) return;
2404
2405 {
2406 // Actually throw the Throwable against the target Thread - however
2407 // only if there is no thread death exception installed already.
2408 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2409 // If the topmost frame is a runtime stub, then we are calling into
2410 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2411 // must deoptimize the caller before continuing, as the compiled exception handler table
2412 // may not be valid
2413 if (has_last_Java_frame()) {
2414 frame f = last_frame();
2415 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2416 RegisterMap reg_map(this, false);
2417 frame compiled_frame = f.sender(®_map);
2418 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2419 Deoptimization::deoptimize(this, compiled_frame);
2420 }
2421 }
2422 }
2423
2424 // Set async. pending exception in thread.
2425 set_pending_async_exception(java_throwable);
2426
2427 if (log_is_enabled(Info, exceptions)) {
2428 ResourceMark rm;
2429 log_info(exceptions)("Pending Async. exception installed of type: %s",
2430 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2431 }
2432 // for AbortVMOnException flag
2433 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2434 }
2435 }
2436
2437
2438 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
2439 java_lang_Thread::set_interrupted(threadObj(), true);
2440 this->interrupt();
2441 }
2442
2443 // External suspension mechanism.
2444 //
2445 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2446 // to any VM_locks and it is at a transition
2447 // Self-suspension will happen on the transition out of the vm.
2448 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2449 //
2450 // Guarantees on return:
2451 // + Target thread will not execute any new bytecode (that's why we need to
2452 // force a safepoint)
2453 // + Target thread will not enter any new monitors
2454 //
2455 void JavaThread::java_suspend() {
2456 ThreadsListHandle tlh;
2457 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2458 return;
2459 }
2460
2461 { MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2462 if (!is_external_suspend()) {
2463 // a racing resume has cancelled us; bail out now
2464 return;
2465 }
2466
2467 // suspend is done
2468 uint32_t debug_bits = 0;
2469 // Warning: is_ext_suspend_completed() may temporarily drop the
2470 // SR_lock to allow the thread to reach a stable thread state if
2471 // it is currently in a transient thread state.
2472 if (is_ext_suspend_completed(false /* !called_by_wait */,
2473 SuspendRetryDelay, &debug_bits)) {
2474 return;
2475 }
2476 }
2477
2478 if (Thread::current() == this) {
2479 // Safely self-suspend.
2480 // If we don't do this explicitly it will implicitly happen
2481 // before we transition back to Java, and on some other thread-state
2482 // transition paths, but not as we exit a JVM TI SuspendThread call.
2483 // As SuspendThread(current) must not return (until resumed) we must
2484 // self-suspend here.
2485 ThreadBlockInVM tbivm(this);
2486 java_suspend_self();
2487 } else {
2488 VM_ThreadSuspend vm_suspend;
2489 VMThread::execute(&vm_suspend);
2490 }
2491 }
2492
2493 // Part II of external suspension.
2494 // A JavaThread self suspends when it detects a pending external suspend
2495 // request. This is usually on transitions. It is also done in places
2496 // where continuing to the next transition would surprise the caller,
2497 // e.g., monitor entry.
2498 //
2499 // Returns the number of times that the thread self-suspended.
2500 //
2501 // Note: DO NOT call java_suspend_self() when you just want to block current
2502 // thread. java_suspend_self() is the second stage of cooperative
2503 // suspension for external suspend requests and should only be used
2504 // to complete an external suspend request.
2505 //
2506 int JavaThread::java_suspend_self() {
2507 assert(thread_state() == _thread_blocked, "wrong state for java_suspend_self()");
2508 int ret = 0;
2509
2510 // we are in the process of exiting so don't suspend
2511 if (is_exiting()) {
2512 clear_external_suspend();
2513 return ret;
2514 }
2515
2516 assert(_anchor.walkable() ||
2517 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2518 "must have walkable stack");
2519
2520 MonitorLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2521
2522 assert(!this->is_ext_suspended(),
2523 "a thread trying to self-suspend should not already be suspended");
2524
2525 if (this->is_suspend_equivalent()) {
2526 // If we are self-suspending as a result of the lifting of a
2527 // suspend equivalent condition, then the suspend_equivalent
2528 // flag is not cleared until we set the ext_suspended flag so
2529 // that wait_for_ext_suspend_completion() returns consistent
2530 // results.
2531 this->clear_suspend_equivalent();
2532 }
2533
2534 // A racing resume may have cancelled us before we grabbed SR_lock
2535 // above. Or another external suspend request could be waiting for us
2536 // by the time we return from SR_lock()->wait(). The thread
2537 // that requested the suspension may already be trying to walk our
2538 // stack and if we return now, we can change the stack out from under
2539 // it. This would be a "bad thing (TM)" and cause the stack walker
2540 // to crash. We stay self-suspended until there are no more pending
2541 // external suspend requests.
2542 while (is_external_suspend()) {
2543 ret++;
2544 this->set_ext_suspended();
2545
2546 // _ext_suspended flag is cleared by java_resume()
2547 while (is_ext_suspended()) {
2548 ml.wait();
2549 }
2550 }
2551 return ret;
2552 }
2553
2554 // Helper routine to set up the correct thread state before calling java_suspend_self.
2555 // This is called when regular thread-state transition helpers can't be used because
2556 // we can be in various states, in particular _thread_in_native_trans.
2557 // Because this thread is external suspended the safepoint code will count it as at
2558 // a safepoint, regardless of what its actual current thread-state is. But
2559 // is_ext_suspend_completed() may be waiting to see a thread transition from
2560 // _thread_in_native_trans to _thread_blocked. So we set the thread state directly
2561 // to _thread_blocked. The problem with setting thread state directly is that a
2562 // safepoint could happen just after java_suspend_self() returns after being resumed,
2563 // and the VM thread will see the _thread_blocked state. So we must check for a safepoint
2564 // after restoring the state to make sure we won't leave while a safepoint is in progress.
2565 // However, not all initial-states are allowed when performing a safepoint check, as we
2566 // should never be blocking at a safepoint whilst in those states. Of these 'bad' states
2567 // only _thread_in_native is possible when executing this code (based on our two callers).
2568 // A thread that is _thread_in_native is already safepoint-safe and so it doesn't matter
2569 // whether the VMThread sees the _thread_blocked state, or the _thread_in_native state,
2570 // and so we don't need the explicit safepoint check.
2571
2572 void JavaThread::java_suspend_self_with_safepoint_check() {
2573 assert(this == Thread::current(), "invariant");
2574 JavaThreadState state = thread_state();
2575 set_thread_state(_thread_blocked);
2576 java_suspend_self();
2577 set_thread_state_fence(state);
2578 // Since we are not using a regular thread-state transition helper here,
2579 // we must manually emit the instruction barrier after leaving a safe state.
2580 OrderAccess::cross_modify_fence();
2581 if (state != _thread_in_native) {
2582 SafepointMechanism::block_if_requested(this);
2583 }
2584 }
2585
2586 #ifdef ASSERT
2587 // Verify the JavaThread has not yet been published in the Threads::list, and
2588 // hence doesn't need protection from concurrent access at this stage.
2589 void JavaThread::verify_not_published() {
2590 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2591 // since an unpublished JavaThread doesn't participate in the
2592 // Thread-SMR protocol for keeping a ThreadsList alive.
2593 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2594 }
2595 #endif
2596
2597 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2598 // progress or when _suspend_flags is non-zero.
2599 // Current thread needs to self-suspend if there is a suspend request and/or
2600 // block if a safepoint is in progress.
2601 // Async exception ISN'T checked.
2602 // Note only the ThreadInVMfromNative transition can call this function
2603 // directly and when thread state is _thread_in_native_trans
2604 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2605 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2606
2607 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2608
2609 if (thread->is_external_suspend()) {
2610 thread->java_suspend_self_with_safepoint_check();
2611 } else {
2612 SafepointMechanism::block_if_requested(thread);
2613 }
2614
2615 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2616 }
2617
2618 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2619 // progress or when _suspend_flags is non-zero.
2620 // Current thread needs to self-suspend if there is a suspend request and/or
2621 // block if a safepoint is in progress.
2622 // Also check for pending async exception (not including unsafe access error).
2623 // Note only the native==>VM/Java barriers can call this function and when
2624 // thread state is _thread_in_native_trans.
2625 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2626 check_safepoint_and_suspend_for_native_trans(thread);
2627
2628 if (thread->has_async_exception()) {
2629 // We are in _thread_in_native_trans state, don't handle unsafe
2630 // access error since that may block.
2631 thread->check_and_handle_async_exceptions(false);
2632 }
2633 }
2634
2635 // This is a variant of the normal
2636 // check_special_condition_for_native_trans with slightly different
2637 // semantics for use by critical native wrappers. It does all the
2638 // normal checks but also performs the transition back into
2639 // thread_in_Java state. This is required so that critical natives
2640 // can potentially block and perform a GC if they are the last thread
2641 // exiting the GCLocker.
2642 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2643 check_special_condition_for_native_trans(thread);
2644
2645 // Finish the transition
2646 thread->set_thread_state(_thread_in_Java);
2647
2648 if (thread->do_critical_native_unlock()) {
2649 ThreadInVMfromJavaNoAsyncException tiv(thread);
2650 GCLocker::unlock_critical(thread);
2651 thread->clear_critical_native_unlock();
2652 }
2653 }
2654
2655 // We need to guarantee the Threads_lock here, since resumes are not
2656 // allowed during safepoint synchronization
2657 // Can only resume from an external suspension
2658 void JavaThread::java_resume() {
2659 assert_locked_or_safepoint(Threads_lock);
2660
2661 // Sanity check: thread is gone, has started exiting or the thread
2662 // was not externally suspended.
2663 ThreadsListHandle tlh;
2664 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2665 return;
2666 }
2667
2668 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2669
2670 clear_external_suspend();
2671
2672 if (is_ext_suspended()) {
2673 clear_ext_suspended();
2674 SR_lock()->notify_all();
2675 }
2676 }
2677
2678 size_t JavaThread::_stack_red_zone_size = 0;
2679 size_t JavaThread::_stack_yellow_zone_size = 0;
2680 size_t JavaThread::_stack_reserved_zone_size = 0;
2681 size_t JavaThread::_stack_shadow_zone_size = 0;
2682
2683 void JavaThread::create_stack_guard_pages() {
2684 if (!os::uses_stack_guard_pages() ||
2685 _stack_guard_state != stack_guard_unused ||
2686 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2687 log_info(os, thread)("Stack guard page creation for thread "
2688 UINTX_FORMAT " disabled", os::current_thread_id());
2689 return;
2690 }
2691 address low_addr = stack_end();
2692 size_t len = stack_guard_zone_size();
2693
2694 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2695 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2696
2697 int must_commit = os::must_commit_stack_guard_pages();
2698 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2699
2700 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2701 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2702 return;
2703 }
2704
2705 if (os::guard_memory((char *) low_addr, len)) {
2706 _stack_guard_state = stack_guard_enabled;
2707 } else {
2708 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2709 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2710 if (os::uncommit_memory((char *) low_addr, len)) {
2711 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2712 }
2713 return;
2714 }
2715
2716 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2717 PTR_FORMAT "-" PTR_FORMAT ".",
2718 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2719 }
2720
2721 void JavaThread::remove_stack_guard_pages() {
2722 assert(Thread::current() == this, "from different thread");
2723 if (_stack_guard_state == stack_guard_unused) return;
2724 address low_addr = stack_end();
2725 size_t len = stack_guard_zone_size();
2726
2727 if (os::must_commit_stack_guard_pages()) {
2728 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2729 _stack_guard_state = stack_guard_unused;
2730 } else {
2731 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2732 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2733 return;
2734 }
2735 } else {
2736 if (_stack_guard_state == stack_guard_unused) return;
2737 if (os::unguard_memory((char *) low_addr, len)) {
2738 _stack_guard_state = stack_guard_unused;
2739 } else {
2740 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2741 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2742 return;
2743 }
2744 }
2745
2746 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2747 PTR_FORMAT "-" PTR_FORMAT ".",
2748 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2749 }
2750
2751 void JavaThread::enable_stack_reserved_zone() {
2752 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state");
2753
2754 // The base notation is from the stack's point of view, growing downward.
2755 // We need to adjust it to work correctly with guard_memory()
2756 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2757
2758 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2759 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2760
2761 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2762 _stack_guard_state = stack_guard_enabled;
2763 } else {
2764 warning("Attempt to guard stack reserved zone failed.");
2765 }
2766 enable_register_stack_guard();
2767 }
2768
2769 void JavaThread::disable_stack_reserved_zone() {
2770 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state");
2771
2772 // Simply return if called for a thread that does not use guard pages.
2773 if (_stack_guard_state != stack_guard_enabled) return;
2774
2775 // The base notation is from the stack's point of view, growing downward.
2776 // We need to adjust it to work correctly with guard_memory()
2777 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2778
2779 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2780 _stack_guard_state = stack_guard_reserved_disabled;
2781 } else {
2782 warning("Attempt to unguard stack reserved zone failed.");
2783 }
2784 disable_register_stack_guard();
2785 }
2786
2787 void JavaThread::enable_stack_yellow_reserved_zone() {
2788 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2789 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2790
2791 // The base notation is from the stacks point of view, growing downward.
2792 // We need to adjust it to work correctly with guard_memory()
2793 address base = stack_red_zone_base();
2794
2795 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2796 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2797
2798 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2799 _stack_guard_state = stack_guard_enabled;
2800 } else {
2801 warning("Attempt to guard stack yellow zone failed.");
2802 }
2803 enable_register_stack_guard();
2804 }
2805
2806 void JavaThread::disable_stack_yellow_reserved_zone() {
2807 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2808 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2809
2810 // Simply return if called for a thread that does not use guard pages.
2811 if (_stack_guard_state == stack_guard_unused) return;
2812
2813 // The base notation is from the stacks point of view, growing downward.
2814 // We need to adjust it to work correctly with guard_memory()
2815 address base = stack_red_zone_base();
2816
2817 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2818 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2819 } else {
2820 warning("Attempt to unguard stack yellow zone failed.");
2821 }
2822 disable_register_stack_guard();
2823 }
2824
2825 void JavaThread::enable_stack_red_zone() {
2826 // The base notation is from the stacks point of view, growing downward.
2827 // We need to adjust it to work correctly with guard_memory()
2828 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2829 address base = stack_red_zone_base() - stack_red_zone_size();
2830
2831 guarantee(base < stack_base(), "Error calculating stack red zone");
2832 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2833
2834 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2835 warning("Attempt to guard stack red zone failed.");
2836 }
2837 }
2838
2839 void JavaThread::disable_stack_red_zone() {
2840 // The base notation is from the stacks point of view, growing downward.
2841 // We need to adjust it to work correctly with guard_memory()
2842 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2843 address base = stack_red_zone_base() - stack_red_zone_size();
2844 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2845 warning("Attempt to unguard stack red zone failed.");
2846 }
2847 }
2848
2849 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2850 // ignore is there is no stack
2851 if (!has_last_Java_frame()) return;
2852 // traverse the stack frames. Starts from top frame.
2853 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2854 frame* fr = fst.current();
2855 f(fr, fst.register_map());
2856 }
2857 }
2858
2859
2860 #ifndef PRODUCT
2861 // Deoptimization
2862 // Function for testing deoptimization
2863 void JavaThread::deoptimize() {
2864 StackFrameStream fst(this, false);
2865 bool deopt = false; // Dump stack only if a deopt actually happens.
2866 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2867 // Iterate over all frames in the thread and deoptimize
2868 for (; !fst.is_done(); fst.next()) {
2869 if (fst.current()->can_be_deoptimized()) {
2870
2871 if (only_at) {
2872 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2873 // consists of comma or carriage return separated numbers so
2874 // search for the current bci in that string.
2875 address pc = fst.current()->pc();
2876 nmethod* nm = (nmethod*) fst.current()->cb();
2877 ScopeDesc* sd = nm->scope_desc_at(pc);
2878 char buffer[8];
2879 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2880 size_t len = strlen(buffer);
2881 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2882 while (found != NULL) {
2883 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2884 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2885 // Check that the bci found is bracketed by terminators.
2886 break;
2887 }
2888 found = strstr(found + 1, buffer);
2889 }
2890 if (!found) {
2891 continue;
2892 }
2893 }
2894
2895 if (DebugDeoptimization && !deopt) {
2896 deopt = true; // One-time only print before deopt
2897 tty->print_cr("[BEFORE Deoptimization]");
2898 trace_frames();
2899 trace_stack();
2900 }
2901 Deoptimization::deoptimize(this, *fst.current());
2902 }
2903 }
2904
2905 if (DebugDeoptimization && deopt) {
2906 tty->print_cr("[AFTER Deoptimization]");
2907 trace_frames();
2908 }
2909 }
2910
2911
2912 // Make zombies
2913 void JavaThread::make_zombies() {
2914 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2915 if (fst.current()->can_be_deoptimized()) {
2916 // it is a Java nmethod
2917 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2918 nm->make_not_entrant();
2919 }
2920 }
2921 }
2922 #endif // PRODUCT
2923
2924
2925 void JavaThread::deoptimize_marked_methods() {
2926 if (!has_last_Java_frame()) return;
2927 StackFrameStream fst(this, false);
2928 for (; !fst.is_done(); fst.next()) {
2929 if (fst.current()->should_be_deoptimized()) {
2930 Deoptimization::deoptimize(this, *fst.current());
2931 }
2932 }
2933 }
2934
2935 // If the caller is a NamedThread, then remember, in the current scope,
2936 // the given JavaThread in its _processed_thread field.
2937 class RememberProcessedThread: public StackObj {
2938 NamedThread* _cur_thr;
2939 public:
2940 RememberProcessedThread(JavaThread* jthr) {
2941 Thread* thread = Thread::current();
2942 if (thread->is_Named_thread()) {
2943 _cur_thr = (NamedThread *)thread;
2944 _cur_thr->set_processed_thread(jthr);
2945 } else {
2946 _cur_thr = NULL;
2947 }
2948 }
2949
2950 ~RememberProcessedThread() {
2951 if (_cur_thr) {
2952 _cur_thr->set_processed_thread(NULL);
2953 }
2954 }
2955 };
2956
2957 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2958 // Verify that the deferred card marks have been flushed.
2959 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2960
2961 // Traverse the GCHandles
2962 Thread::oops_do(f, cf);
2963
2964 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2965 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2966
2967 if (has_last_Java_frame()) {
2968 // Record JavaThread to GC thread
2969 RememberProcessedThread rpt(this);
2970
2971 // traverse the registered growable array
2972 if (_array_for_gc != NULL) {
2973 for (int index = 0; index < _array_for_gc->length(); index++) {
2974 f->do_oop(_array_for_gc->adr_at(index));
2975 }
2976 }
2977
2978 // Traverse the monitor chunks
2979 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2980 chunk->oops_do(f);
2981 }
2982
2983 // Traverse the execution stack
2984 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2985 fst.current()->oops_do(f, cf, fst.register_map());
2986 }
2987 }
2988
2989 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2990 // If we have deferred set_locals there might be oops waiting to be
2991 // written
2992 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2993 if (list != NULL) {
2994 for (int i = 0; i < list->length(); i++) {
2995 list->at(i)->oops_do(f);
2996 }
2997 }
2998
2999 // Traverse instance variables at the end since the GC may be moving things
3000 // around using this function
3001 f->do_oop((oop*) &_threadObj);
3002 f->do_oop((oop*) &_vm_result);
3003 f->do_oop((oop*) &_exception_oop);
3004 f->do_oop((oop*) &_pending_async_exception);
3005
3006 if (jvmti_thread_state() != NULL) {
3007 jvmti_thread_state()->oops_do(f, cf);
3008 }
3009 }
3010
3011 #ifdef ASSERT
3012 void JavaThread::verify_states_for_handshake() {
3013 // This checks that the thread has a correct frame state during a handshake.
3014 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
3015 (has_last_Java_frame() && java_call_counter() > 0),
3016 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
3017 has_last_Java_frame(), java_call_counter());
3018 }
3019 #endif
3020
3021 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
3022 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
3023 (has_last_Java_frame() && java_call_counter() > 0),
3024 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
3025 has_last_Java_frame(), java_call_counter());
3026
3027 if (has_last_Java_frame()) {
3028 // Traverse the execution stack
3029 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3030 fst.current()->nmethods_do(cf);
3031 }
3032 }
3033
3034 if (jvmti_thread_state() != NULL) {
3035 jvmti_thread_state()->nmethods_do(cf);
3036 }
3037 }
3038
3039 void JavaThread::metadata_do(MetadataClosure* f) {
3040 if (has_last_Java_frame()) {
3041 // Traverse the execution stack to call f() on the methods in the stack
3042 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3043 fst.current()->metadata_do(f);
3044 }
3045 } else if (is_Compiler_thread()) {
3046 // need to walk ciMetadata in current compile tasks to keep alive.
3047 CompilerThread* ct = (CompilerThread*)this;
3048 if (ct->env() != NULL) {
3049 ct->env()->metadata_do(f);
3050 }
3051 CompileTask* task = ct->task();
3052 if (task != NULL) {
3053 task->metadata_do(f);
3054 }
3055 }
3056 }
3057
3058 // Printing
3059 const char* _get_thread_state_name(JavaThreadState _thread_state) {
3060 switch (_thread_state) {
3061 case _thread_uninitialized: return "_thread_uninitialized";
3062 case _thread_new: return "_thread_new";
3063 case _thread_new_trans: return "_thread_new_trans";
3064 case _thread_in_native: return "_thread_in_native";
3065 case _thread_in_native_trans: return "_thread_in_native_trans";
3066 case _thread_in_vm: return "_thread_in_vm";
3067 case _thread_in_vm_trans: return "_thread_in_vm_trans";
3068 case _thread_in_Java: return "_thread_in_Java";
3069 case _thread_in_Java_trans: return "_thread_in_Java_trans";
3070 case _thread_blocked: return "_thread_blocked";
3071 case _thread_blocked_trans: return "_thread_blocked_trans";
3072 default: return "unknown thread state";
3073 }
3074 }
3075
3076 #ifndef PRODUCT
3077 void JavaThread::print_thread_state_on(outputStream *st) const {
3078 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
3079 };
3080 #endif // PRODUCT
3081
3082 // Called by Threads::print() for VM_PrintThreads operation
3083 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
3084 st->print_raw("\"");
3085 st->print_raw(get_thread_name());
3086 st->print_raw("\" ");
3087 oop thread_oop = threadObj();
3088 if (thread_oop != NULL) {
3089 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
3090 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
3091 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
3092 }
3093 Thread::print_on(st, print_extended_info);
3094 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
3095 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
3096 if (thread_oop != NULL) {
3097 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3098 }
3099 #ifndef PRODUCT
3100 _safepoint_state->print_on(st);
3101 #endif // PRODUCT
3102 if (is_Compiler_thread()) {
3103 CompileTask *task = ((CompilerThread*)this)->task();
3104 if (task != NULL) {
3105 st->print(" Compiling: ");
3106 task->print(st, NULL, true, false);
3107 } else {
3108 st->print(" No compile task");
3109 }
3110 st->cr();
3111 }
3112 }
3113
3114 void JavaThread::print() const { print_on(tty); }
3115
3116 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3117 st->print("%s", get_thread_name_string(buf, buflen));
3118 }
3119
3120 // Called by fatal error handler. The difference between this and
3121 // JavaThread::print() is that we can't grab lock or allocate memory.
3122 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3123 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3124 oop thread_obj = threadObj();
3125 if (thread_obj != NULL) {
3126 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3127 }
3128 st->print(" [");
3129 st->print("%s", _get_thread_state_name(_thread_state));
3130 if (osthread()) {
3131 st->print(", id=%d", osthread()->thread_id());
3132 }
3133 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3134 p2i(stack_end()), p2i(stack_base()));
3135 st->print("]");
3136
3137 ThreadsSMRSupport::print_info_on(this, st);
3138 return;
3139 }
3140
3141 // Verification
3142
3143 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3144
3145 void JavaThread::verify() {
3146 // Verify oops in the thread.
3147 oops_do(&VerifyOopClosure::verify_oop, NULL);
3148
3149 // Verify the stack frames.
3150 frames_do(frame_verify);
3151 }
3152
3153 // CR 6300358 (sub-CR 2137150)
3154 // Most callers of this method assume that it can't return NULL but a
3155 // thread may not have a name whilst it is in the process of attaching to
3156 // the VM - see CR 6412693, and there are places where a JavaThread can be
3157 // seen prior to having it's threadObj set (eg JNI attaching threads and
3158 // if vm exit occurs during initialization). These cases can all be accounted
3159 // for such that this method never returns NULL.
3160 const char* JavaThread::get_thread_name() const {
3161 #ifdef ASSERT
3162 // early safepoints can hit while current thread does not yet have TLS
3163 if (!SafepointSynchronize::is_at_safepoint()) {
3164 Thread *cur = Thread::current();
3165 if (!(cur->is_Java_thread() && cur == this)) {
3166 // Current JavaThreads are allowed to get their own name without
3167 // the Threads_lock.
3168 assert_locked_or_safepoint_or_handshake(Threads_lock, this);
3169 }
3170 }
3171 #endif // ASSERT
3172 return get_thread_name_string();
3173 }
3174
3175 // Returns a non-NULL representation of this thread's name, or a suitable
3176 // descriptive string if there is no set name
3177 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3178 const char* name_str;
3179 oop thread_obj = threadObj();
3180 if (thread_obj != NULL) {
3181 oop name = java_lang_Thread::name(thread_obj);
3182 if (name != NULL) {
3183 if (buf == NULL) {
3184 name_str = java_lang_String::as_utf8_string(name);
3185 } else {
3186 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3187 }
3188 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3189 name_str = "<no-name - thread is attaching>";
3190 } else {
3191 name_str = Thread::name();
3192 }
3193 } else {
3194 name_str = Thread::name();
3195 }
3196 assert(name_str != NULL, "unexpected NULL thread name");
3197 return name_str;
3198 }
3199
3200 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3201
3202 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3203 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
3204 // Link Java Thread object <-> C++ Thread
3205
3206 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3207 // and put it into a new Handle. The Handle "thread_oop" can then
3208 // be used to pass the C++ thread object to other methods.
3209
3210 // Set the Java level thread object (jthread) field of the
3211 // new thread (a JavaThread *) to C++ thread object using the
3212 // "thread_oop" handle.
3213
3214 // Set the thread field (a JavaThread *) of the
3215 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3216
3217 Handle thread_oop(Thread::current(),
3218 JNIHandles::resolve_non_null(jni_thread));
3219 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3220 "must be initialized");
3221 set_threadObj(thread_oop());
3222 java_lang_Thread::set_thread(thread_oop(), this);
3223
3224 if (prio == NoPriority) {
3225 prio = java_lang_Thread::priority(thread_oop());
3226 assert(prio != NoPriority, "A valid priority should be present");
3227 }
3228
3229 // Push the Java priority down to the native thread; needs Threads_lock
3230 Thread::set_priority(this, prio);
3231
3232 // Add the new thread to the Threads list and set it in motion.
3233 // We must have threads lock in order to call Threads::add.
3234 // It is crucial that we do not block before the thread is
3235 // added to the Threads list for if a GC happens, then the java_thread oop
3236 // will not be visited by GC.
3237 Threads::add(this);
3238 }
3239
3240 oop JavaThread::current_park_blocker() {
3241 // Support for JSR-166 locks
3242 oop thread_oop = threadObj();
3243 if (thread_oop != NULL) {
3244 return java_lang_Thread::park_blocker(thread_oop);
3245 }
3246 return NULL;
3247 }
3248
3249
3250 void JavaThread::print_stack_on(outputStream* st) {
3251 if (!has_last_Java_frame()) return;
3252 ResourceMark rm;
3253 HandleMark hm;
3254
3255 RegisterMap reg_map(this);
3256 vframe* start_vf = last_java_vframe(®_map);
3257 int count = 0;
3258 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3259 if (f->is_java_frame()) {
3260 javaVFrame* jvf = javaVFrame::cast(f);
3261 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3262
3263 // Print out lock information
3264 if (JavaMonitorsInStackTrace) {
3265 jvf->print_lock_info_on(st, count);
3266 }
3267 } else {
3268 // Ignore non-Java frames
3269 }
3270
3271 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3272 count++;
3273 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3274 }
3275 }
3276
3277
3278 // JVMTI PopFrame support
3279 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3280 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3281 if (in_bytes(size_in_bytes) != 0) {
3282 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3283 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3284 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3285 }
3286 }
3287
3288 void* JavaThread::popframe_preserved_args() {
3289 return _popframe_preserved_args;
3290 }
3291
3292 ByteSize JavaThread::popframe_preserved_args_size() {
3293 return in_ByteSize(_popframe_preserved_args_size);
3294 }
3295
3296 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3297 int sz = in_bytes(popframe_preserved_args_size());
3298 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3299 return in_WordSize(sz / wordSize);
3300 }
3301
3302 void JavaThread::popframe_free_preserved_args() {
3303 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3304 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
3305 _popframe_preserved_args = NULL;
3306 _popframe_preserved_args_size = 0;
3307 }
3308
3309 #ifndef PRODUCT
3310
3311 void JavaThread::trace_frames() {
3312 tty->print_cr("[Describe stack]");
3313 int frame_no = 1;
3314 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3315 tty->print(" %d. ", frame_no++);
3316 fst.current()->print_value_on(tty, this);
3317 tty->cr();
3318 }
3319 }
3320
3321 class PrintAndVerifyOopClosure: public OopClosure {
3322 protected:
3323 template <class T> inline void do_oop_work(T* p) {
3324 oop obj = RawAccess<>::oop_load(p);
3325 if (obj == NULL) return;
3326 tty->print(INTPTR_FORMAT ": ", p2i(p));
3327 if (oopDesc::is_oop_or_null(obj)) {
3328 if (obj->is_objArray()) {
3329 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3330 } else {
3331 obj->print();
3332 }
3333 } else {
3334 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3335 }
3336 tty->cr();
3337 }
3338 public:
3339 virtual void do_oop(oop* p) { do_oop_work(p); }
3340 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3341 };
3342
3343 #ifdef ASSERT
3344 // Print or validate the layout of stack frames
3345 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3346 ResourceMark rm;
3347 PRESERVE_EXCEPTION_MARK;
3348 FrameValues values;
3349 int frame_no = 0;
3350 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3351 fst.current()->describe(values, ++frame_no);
3352 if (depth == frame_no) break;
3353 }
3354 if (validate_only) {
3355 values.validate();
3356 } else {
3357 tty->print_cr("[Describe stack layout]");
3358 values.print(this);
3359 }
3360 }
3361 #endif
3362
3363 void JavaThread::trace_stack_from(vframe* start_vf) {
3364 ResourceMark rm;
3365 int vframe_no = 1;
3366 for (vframe* f = start_vf; f; f = f->sender()) {
3367 if (f->is_java_frame()) {
3368 javaVFrame::cast(f)->print_activation(vframe_no++);
3369 } else {
3370 f->print();
3371 }
3372 if (vframe_no > StackPrintLimit) {
3373 tty->print_cr("...<more frames>...");
3374 return;
3375 }
3376 }
3377 }
3378
3379
3380 void JavaThread::trace_stack() {
3381 if (!has_last_Java_frame()) return;
3382 ResourceMark rm;
3383 HandleMark hm;
3384 RegisterMap reg_map(this);
3385 trace_stack_from(last_java_vframe(®_map));
3386 }
3387
3388
3389 #endif // PRODUCT
3390
3391
3392 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3393 assert(reg_map != NULL, "a map must be given");
3394 frame f = last_frame();
3395 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3396 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3397 }
3398 return NULL;
3399 }
3400
3401
3402 Klass* JavaThread::security_get_caller_class(int depth) {
3403 vframeStream vfst(this);
3404 vfst.security_get_caller_frame(depth);
3405 if (!vfst.at_end()) {
3406 return vfst.method()->method_holder();
3407 }
3408 return NULL;
3409 }
3410
3411 // java.lang.Thread.sleep support
3412 // Returns true if sleep time elapsed as expected, and false
3413 // if the thread was interrupted.
3414 bool JavaThread::sleep(jlong millis) {
3415 assert(this == Thread::current(), "thread consistency check");
3416
3417 ParkEvent * const slp = this->_SleepEvent;
3418 // Because there can be races with thread interruption sending an unpark()
3419 // to the event, we explicitly reset it here to avoid an immediate return.
3420 // The actual interrupt state will be checked before we park().
3421 slp->reset();
3422 // Thread interruption establishes a happens-before ordering in the
3423 // Java Memory Model, so we need to ensure we synchronize with the
3424 // interrupt state.
3425 OrderAccess::fence();
3426
3427 jlong prevtime = os::javaTimeNanos();
3428
3429 for (;;) {
3430 // interruption has precedence over timing out
3431 if (this->is_interrupted(true)) {
3432 return false;
3433 }
3434
3435 if (millis <= 0) {
3436 return true;
3437 }
3438
3439 {
3440 ThreadBlockInVM tbivm(this);
3441 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
3442
3443 this->set_suspend_equivalent();
3444 // cleared by handle_special_suspend_equivalent_condition() or
3445 // java_suspend_self() via check_and_wait_while_suspended()
3446
3447 slp->park(millis);
3448
3449 // were we externally suspended while we were waiting?
3450 this->check_and_wait_while_suspended();
3451 }
3452
3453 // Update elapsed time tracking
3454 jlong newtime = os::javaTimeNanos();
3455 if (newtime - prevtime < 0) {
3456 // time moving backwards, should only happen if no monotonic clock
3457 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3458 assert(!os::supports_monotonic_clock(),
3459 "unexpected time moving backwards detected in JavaThread::sleep()");
3460 } else {
3461 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3462 }
3463 prevtime = newtime;
3464 }
3465 }
3466
3467 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3468 assert(thread->is_Compiler_thread(), "must be compiler thread");
3469 CompileBroker::compiler_thread_loop();
3470 }
3471
3472 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3473 NMethodSweeper::sweeper_loop();
3474 }
3475
3476 // Create a CompilerThread
3477 CompilerThread::CompilerThread(CompileQueue* queue,
3478 CompilerCounters* counters)
3479 : JavaThread(&compiler_thread_entry) {
3480 _env = NULL;
3481 _log = NULL;
3482 _task = NULL;
3483 _queue = queue;
3484 _counters = counters;
3485 _buffer_blob = NULL;
3486 _compiler = NULL;
3487
3488 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3489 resource_area()->bias_to(mtCompiler);
3490
3491 #ifndef PRODUCT
3492 _ideal_graph_printer = NULL;
3493 #endif
3494 }
3495
3496 CompilerThread::~CompilerThread() {
3497 // Delete objects which were allocated on heap.
3498 delete _counters;
3499 }
3500
3501 bool CompilerThread::can_call_java() const {
3502 return _compiler != NULL && _compiler->is_jvmci();
3503 }
3504
3505 // Create sweeper thread
3506 CodeCacheSweeperThread::CodeCacheSweeperThread()
3507 : JavaThread(&sweeper_thread_entry) {
3508 _scanned_compiled_method = NULL;
3509 }
3510
3511 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3512 JavaThread::oops_do(f, cf);
3513 if (_scanned_compiled_method != NULL && cf != NULL) {
3514 // Safepoints can occur when the sweeper is scanning an nmethod so
3515 // process it here to make sure it isn't unloaded in the middle of
3516 // a scan.
3517 cf->do_code_blob(_scanned_compiled_method);
3518 }
3519 }
3520
3521 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3522 JavaThread::nmethods_do(cf);
3523 if (_scanned_compiled_method != NULL && cf != NULL) {
3524 // Safepoints can occur when the sweeper is scanning an nmethod so
3525 // process it here to make sure it isn't unloaded in the middle of
3526 // a scan.
3527 cf->do_code_blob(_scanned_compiled_method);
3528 }
3529 }
3530
3531
3532 // ======= Threads ========
3533
3534 // The Threads class links together all active threads, and provides
3535 // operations over all threads. It is protected by the Threads_lock,
3536 // which is also used in other global contexts like safepointing.
3537 // ThreadsListHandles are used to safely perform operations on one
3538 // or more threads without the risk of the thread exiting during the
3539 // operation.
3540 //
3541 // Note: The Threads_lock is currently more widely used than we
3542 // would like. We are actively migrating Threads_lock uses to other
3543 // mechanisms in order to reduce Threads_lock contention.
3544
3545 int Threads::_number_of_threads = 0;
3546 int Threads::_number_of_non_daemon_threads = 0;
3547 int Threads::_return_code = 0;
3548 uintx Threads::_thread_claim_token = 1; // Never zero.
3549 size_t JavaThread::_stack_size_at_create = 0;
3550
3551 #ifdef ASSERT
3552 bool Threads::_vm_complete = false;
3553 #endif
3554
3555 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3556 Prefetch::read((void*)addr, prefetch_interval);
3557 return *addr;
3558 }
3559
3560 // Possibly the ugliest for loop the world has seen. C++ does not allow
3561 // multiple types in the declaration section of the for loop. In this case
3562 // we are only dealing with pointers and hence can cast them. It looks ugly
3563 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3564 #define DO_JAVA_THREADS(LIST, X) \
3565 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3566 *MACRO_list = (JavaThread*)(LIST), \
3567 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3568 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3569 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3570 MACRO_current_p != MACRO_end; \
3571 MACRO_current_p++, \
3572 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3573
3574 // All JavaThreads
3575 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3576
3577 // All NonJavaThreads (i.e., every non-JavaThread in the system).
3578 void Threads::non_java_threads_do(ThreadClosure* tc) {
3579 NoSafepointVerifier nsv;
3580 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
3581 tc->do_thread(njti.current());
3582 }
3583 }
3584
3585 // All JavaThreads
3586 void Threads::java_threads_do(ThreadClosure* tc) {
3587 assert_locked_or_safepoint(Threads_lock);
3588 // ALL_JAVA_THREADS iterates through all JavaThreads.
3589 ALL_JAVA_THREADS(p) {
3590 tc->do_thread(p);
3591 }
3592 }
3593
3594 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3595 assert_locked_or_safepoint(Threads_lock);
3596 java_threads_do(tc);
3597 tc->do_thread(VMThread::vm_thread());
3598 }
3599
3600 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3601 void Threads::threads_do(ThreadClosure* tc) {
3602 assert_locked_or_safepoint(Threads_lock);
3603 java_threads_do(tc);
3604 non_java_threads_do(tc);
3605 }
3606
3607 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3608 uintx claim_token = Threads::thread_claim_token();
3609 ALL_JAVA_THREADS(p) {
3610 if (p->claim_threads_do(is_par, claim_token)) {
3611 tc->do_thread(p);
3612 }
3613 }
3614 VMThread* vmt = VMThread::vm_thread();
3615 if (vmt->claim_threads_do(is_par, claim_token)) {
3616 tc->do_thread(vmt);
3617 }
3618 }
3619
3620 // The system initialization in the library has three phases.
3621 //
3622 // Phase 1: java.lang.System class initialization
3623 // java.lang.System is a primordial class loaded and initialized
3624 // by the VM early during startup. java.lang.System.<clinit>
3625 // only does registerNatives and keeps the rest of the class
3626 // initialization work later until thread initialization completes.
3627 //
3628 // System.initPhase1 initializes the system properties, the static
3629 // fields in, out, and err. Set up java signal handlers, OS-specific
3630 // system settings, and thread group of the main thread.
3631 static void call_initPhase1(TRAPS) {
3632 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3633 JavaValue result(T_VOID);
3634 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3635 vmSymbols::void_method_signature(), CHECK);
3636 }
3637
3638 // Phase 2. Module system initialization
3639 // This will initialize the module system. Only java.base classes
3640 // can be loaded until phase 2 completes.
3641 //
3642 // Call System.initPhase2 after the compiler initialization and jsr292
3643 // classes get initialized because module initialization runs a lot of java
3644 // code, that for performance reasons, should be compiled. Also, this will
3645 // enable the startup code to use lambda and other language features in this
3646 // phase and onward.
3647 //
3648 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3649 static void call_initPhase2(TRAPS) {
3650 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3651
3652 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3653
3654 JavaValue result(T_INT);
3655 JavaCallArguments args;
3656 args.push_int(DisplayVMOutputToStderr);
3657 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3658 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3659 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3660 if (result.get_jint() != JNI_OK) {
3661 vm_exit_during_initialization(); // no message or exception
3662 }
3663
3664 universe_post_module_init();
3665 }
3666
3667 // Phase 3. final setup - set security manager, system class loader and TCCL
3668 //
3669 // This will instantiate and set the security manager, set the system class
3670 // loader as well as the thread context class loader. The security manager
3671 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3672 // other modules or the application's classpath.
3673 static void call_initPhase3(TRAPS) {
3674 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3675 JavaValue result(T_VOID);
3676 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3677 vmSymbols::void_method_signature(), CHECK);
3678 }
3679
3680 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3681 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3682
3683 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3684 create_vm_init_libraries();
3685 }
3686
3687 initialize_class(vmSymbols::java_lang_String(), CHECK);
3688
3689 // Inject CompactStrings value after the static initializers for String ran.
3690 java_lang_String::set_compact_strings(CompactStrings);
3691
3692 // Initialize java_lang.System (needed before creating the thread)
3693 initialize_class(vmSymbols::java_lang_System(), CHECK);
3694 // The VM creates & returns objects of this class. Make sure it's initialized.
3695 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3696 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3697 Handle thread_group = create_initial_thread_group(CHECK);
3698 Universe::set_main_thread_group(thread_group());
3699 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3700 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3701 main_thread->set_threadObj(thread_object);
3702
3703 // Set thread status to running since main thread has
3704 // been started and running.
3705 java_lang_Thread::set_thread_status(thread_object,
3706 java_lang_Thread::RUNNABLE);
3707
3708 // The VM creates objects of this class.
3709 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3710
3711 #ifdef ASSERT
3712 InstanceKlass *k = SystemDictionary::UnsafeConstants_klass();
3713 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
3714 #endif
3715
3716 // initialize the hardware-specific constants needed by Unsafe
3717 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
3718 jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
3719
3720 // The VM preresolves methods to these classes. Make sure that they get initialized
3721 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3722 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3723
3724 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3725 call_initPhase1(CHECK);
3726
3727 // get the Java runtime name, version, and vendor info after java.lang.System is initialized
3728 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3729 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3730 JDK_Version::set_runtime_vendor_version(get_java_runtime_vendor_version(THREAD));
3731 JDK_Version::set_runtime_vendor_vm_bug_url(get_java_runtime_vendor_vm_bug_url(THREAD));
3732
3733 // an instance of OutOfMemory exception has been allocated earlier
3734 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3735 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3736 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3737 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3738 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3739 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3740 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3741 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3742
3743 // Eager box cache initialization only if AOT is on and any library is loaded.
3744 AOTLoader::initialize_box_caches(CHECK);
3745 }
3746
3747 void Threads::initialize_jsr292_core_classes(TRAPS) {
3748 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3749
3750 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3751 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3752 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3753 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3754 }
3755
3756 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3757 extern void JDK_Version_init();
3758
3759 // Preinitialize version info.
3760 VM_Version::early_initialize();
3761
3762 // Check version
3763 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3764
3765 // Initialize library-based TLS
3766 ThreadLocalStorage::init();
3767
3768 // Initialize the output stream module
3769 ostream_init();
3770
3771 // Process java launcher properties.
3772 Arguments::process_sun_java_launcher_properties(args);
3773
3774 // Initialize the os module
3775 os::init();
3776
3777 // Record VM creation timing statistics
3778 TraceVmCreationTime create_vm_timer;
3779 create_vm_timer.start();
3780
3781 // Initialize system properties.
3782 Arguments::init_system_properties();
3783
3784 // So that JDK version can be used as a discriminator when parsing arguments
3785 JDK_Version_init();
3786
3787 // Update/Initialize System properties after JDK version number is known
3788 Arguments::init_version_specific_system_properties();
3789
3790 // Make sure to initialize log configuration *before* parsing arguments
3791 LogConfiguration::initialize(create_vm_timer.begin_time());
3792
3793 // Parse arguments
3794 // Note: this internally calls os::init_container_support()
3795 jint parse_result = Arguments::parse(args);
3796 if (parse_result != JNI_OK) return parse_result;
3797
3798 os::init_before_ergo();
3799
3800 jint ergo_result = Arguments::apply_ergo();
3801 if (ergo_result != JNI_OK) return ergo_result;
3802
3803 // Final check of all ranges after ergonomics which may change values.
3804 if (!JVMFlagRangeList::check_ranges()) {
3805 return JNI_EINVAL;
3806 }
3807
3808 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3809 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo);
3810 if (!constraint_result) {
3811 return JNI_EINVAL;
3812 }
3813
3814 if (PauseAtStartup) {
3815 os::pause();
3816 }
3817
3818 HOTSPOT_VM_INIT_BEGIN();
3819
3820 // Timing (must come after argument parsing)
3821 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3822
3823 // Initialize the os module after parsing the args
3824 jint os_init_2_result = os::init_2();
3825 if (os_init_2_result != JNI_OK) return os_init_2_result;
3826
3827 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3828 // Initialize assert poison page mechanism.
3829 if (ShowRegistersOnAssert) {
3830 initialize_assert_poison();
3831 }
3832 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3833
3834 SafepointMechanism::initialize();
3835
3836 jint adjust_after_os_result = Arguments::adjust_after_os();
3837 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3838
3839 // Initialize output stream logging
3840 ostream_init_log();
3841
3842 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3843 // Must be before create_vm_init_agents()
3844 if (Arguments::init_libraries_at_startup()) {
3845 convert_vm_init_libraries_to_agents();
3846 }
3847
3848 // Launch -agentlib/-agentpath and converted -Xrun agents
3849 if (Arguments::init_agents_at_startup()) {
3850 create_vm_init_agents();
3851 }
3852
3853 // Initialize Threads state
3854 _number_of_threads = 0;
3855 _number_of_non_daemon_threads = 0;
3856
3857 // Initialize global data structures and create system classes in heap
3858 vm_init_globals();
3859
3860 #if INCLUDE_JVMCI
3861 if (JVMCICounterSize > 0) {
3862 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
3863 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3864 } else {
3865 JavaThread::_jvmci_old_thread_counters = NULL;
3866 }
3867 #endif // INCLUDE_JVMCI
3868
3869 // Attach the main thread to this os thread
3870 JavaThread* main_thread = new JavaThread();
3871 main_thread->set_thread_state(_thread_in_vm);
3872 main_thread->initialize_thread_current();
3873 // must do this before set_active_handles
3874 main_thread->record_stack_base_and_size();
3875 main_thread->register_thread_stack_with_NMT();
3876 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3877
3878 if (!main_thread->set_as_starting_thread()) {
3879 vm_shutdown_during_initialization(
3880 "Failed necessary internal allocation. Out of swap space");
3881 main_thread->smr_delete();
3882 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3883 return JNI_ENOMEM;
3884 }
3885
3886 // Enable guard page *after* os::create_main_thread(), otherwise it would
3887 // crash Linux VM, see notes in os_linux.cpp.
3888 main_thread->create_stack_guard_pages();
3889
3890 // Initialize Java-Level synchronization subsystem
3891 ObjectMonitor::Initialize();
3892
3893 // Initialize global modules
3894 jint status = init_globals();
3895 if (status != JNI_OK) {
3896 main_thread->smr_delete();
3897 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3898 return status;
3899 }
3900
3901 JFR_ONLY(Jfr::on_create_vm_1();)
3902
3903 // Should be done after the heap is fully created
3904 main_thread->cache_global_variables();
3905
3906 HandleMark hm;
3907
3908 { MutexLocker mu(Threads_lock);
3909 Threads::add(main_thread);
3910 }
3911
3912 // Any JVMTI raw monitors entered in onload will transition into
3913 // real raw monitor. VM is setup enough here for raw monitor enter.
3914 JvmtiExport::transition_pending_onload_raw_monitors();
3915
3916 // Create the VMThread
3917 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3918
3919 VMThread::create();
3920 Thread* vmthread = VMThread::vm_thread();
3921
3922 if (!os::create_thread(vmthread, os::vm_thread)) {
3923 vm_exit_during_initialization("Cannot create VM thread. "
3924 "Out of system resources.");
3925 }
3926
3927 // Wait for the VM thread to become ready, and VMThread::run to initialize
3928 // Monitors can have spurious returns, must always check another state flag
3929 {
3930 MonitorLocker ml(Notify_lock);
3931 os::start_thread(vmthread);
3932 while (vmthread->active_handles() == NULL) {
3933 ml.wait();
3934 }
3935 }
3936 }
3937
3938 assert(Universe::is_fully_initialized(), "not initialized");
3939 if (VerifyDuringStartup) {
3940 // Make sure we're starting with a clean slate.
3941 VM_Verify verify_op;
3942 VMThread::execute(&verify_op);
3943 }
3944
3945 // We need this to update the java.vm.info property in case any flags used
3946 // to initially define it have been changed. This is needed for both CDS and
3947 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info
3948 // is initially computed. See Abstract_VM_Version::vm_info_string().
3949 // This update must happen before we initialize the java classes, but
3950 // after any initialization logic that might modify the flags.
3951 Arguments::update_vm_info_property(VM_Version::vm_info_string());
3952
3953 Thread* THREAD = Thread::current();
3954
3955 // Always call even when there are not JVMTI environments yet, since environments
3956 // may be attached late and JVMTI must track phases of VM execution
3957 JvmtiExport::enter_early_start_phase();
3958
3959 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3960 JvmtiExport::post_early_vm_start();
3961
3962 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3963
3964 quicken_jni_functions();
3965
3966 // No more stub generation allowed after that point.
3967 StubCodeDesc::freeze();
3968
3969 // Set flag that basic initialization has completed. Used by exceptions and various
3970 // debug stuff, that does not work until all basic classes have been initialized.
3971 set_init_completed();
3972
3973 LogConfiguration::post_initialize();
3974 Metaspace::post_initialize();
3975
3976 HOTSPOT_VM_INIT_END();
3977
3978 // record VM initialization completion time
3979 #if INCLUDE_MANAGEMENT
3980 Management::record_vm_init_completed();
3981 #endif // INCLUDE_MANAGEMENT
3982
3983 // Signal Dispatcher needs to be started before VMInit event is posted
3984 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3985
3986 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3987 if (!DisableAttachMechanism) {
3988 AttachListener::vm_start();
3989 if (StartAttachListener || AttachListener::init_at_startup()) {
3990 AttachListener::init();
3991 }
3992 }
3993
3994 // Launch -Xrun agents
3995 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3996 // back-end can launch with -Xdebug -Xrunjdwp.
3997 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3998 create_vm_init_libraries();
3999 }
4000
4001 if (CleanChunkPoolAsync) {
4002 Chunk::start_chunk_pool_cleaner_task();
4003 }
4004
4005 // Start the service thread
4006 // The service thread enqueues JVMTI deferred events and does various hashtable
4007 // and other cleanups. Needs to start before the compilers start posting events.
4008 ServiceThread::initialize();
4009
4010 // initialize compiler(s)
4011 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
4012 #if INCLUDE_JVMCI
4013 bool force_JVMCI_intialization = false;
4014 if (EnableJVMCI) {
4015 // Initialize JVMCI eagerly when it is explicitly requested.
4016 // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
4017 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
4018
4019 if (!force_JVMCI_intialization) {
4020 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
4021 // compilations via JVMCI will not actually block until JVMCI is initialized.
4022 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
4023 }
4024 }
4025 #endif
4026 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
4027 // Postpone completion of compiler initialization to after JVMCI
4028 // is initialized to avoid timeouts of blocking compilations.
4029 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
4030 CompileBroker::compilation_init_phase2();
4031 }
4032 #endif
4033
4034 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
4035 // It is done after compilers are initialized, because otherwise compilations of
4036 // signature polymorphic MH intrinsics can be missed
4037 // (see SystemDictionary::find_method_handle_intrinsic).
4038 initialize_jsr292_core_classes(CHECK_JNI_ERR);
4039
4040 // This will initialize the module system. Only java.base classes can be
4041 // loaded until phase 2 completes
4042 call_initPhase2(CHECK_JNI_ERR);
4043
4044 JFR_ONLY(Jfr::on_create_vm_2();)
4045
4046 // Always call even when there are not JVMTI environments yet, since environments
4047 // may be attached late and JVMTI must track phases of VM execution
4048 JvmtiExport::enter_start_phase();
4049
4050 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
4051 JvmtiExport::post_vm_start();
4052
4053 // Final system initialization including security manager and system class loader
4054 call_initPhase3(CHECK_JNI_ERR);
4055
4056 // cache the system and platform class loaders
4057 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
4058
4059 #if INCLUDE_CDS
4060 // capture the module path info from the ModuleEntryTable
4061 ClassLoader::initialize_module_path(THREAD);
4062 #endif
4063
4064 #if INCLUDE_JVMCI
4065 if (force_JVMCI_intialization) {
4066 JVMCI::initialize_compiler(CHECK_JNI_ERR);
4067 CompileBroker::compilation_init_phase2();
4068 }
4069 #endif
4070
4071 // Always call even when there are not JVMTI environments yet, since environments
4072 // may be attached late and JVMTI must track phases of VM execution
4073 JvmtiExport::enter_live_phase();
4074
4075 // Make perfmemory accessible
4076 PerfMemory::set_accessible(true);
4077
4078 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
4079 JvmtiExport::post_vm_initialized();
4080
4081 JFR_ONLY(Jfr::on_create_vm_3();)
4082
4083 #if INCLUDE_MANAGEMENT
4084 Management::initialize(THREAD);
4085
4086 if (HAS_PENDING_EXCEPTION) {
4087 // management agent fails to start possibly due to
4088 // configuration problem and is responsible for printing
4089 // stack trace if appropriate. Simply exit VM.
4090 vm_exit(1);
4091 }
4092 #endif // INCLUDE_MANAGEMENT
4093
4094 if (MemProfiling) MemProfiler::engage();
4095 StatSampler::engage();
4096 if (CheckJNICalls) JniPeriodicChecker::engage();
4097
4098 BiasedLocking::init();
4099
4100 #if INCLUDE_RTM_OPT
4101 RTMLockingCounters::init();
4102 #endif
4103
4104 call_postVMInitHook(THREAD);
4105 // The Java side of PostVMInitHook.run must deal with all
4106 // exceptions and provide means of diagnosis.
4107 if (HAS_PENDING_EXCEPTION) {
4108 CLEAR_PENDING_EXCEPTION;
4109 }
4110
4111 {
4112 MutexLocker ml(PeriodicTask_lock);
4113 // Make sure the WatcherThread can be started by WatcherThread::start()
4114 // or by dynamic enrollment.
4115 WatcherThread::make_startable();
4116 // Start up the WatcherThread if there are any periodic tasks
4117 // NOTE: All PeriodicTasks should be registered by now. If they
4118 // aren't, late joiners might appear to start slowly (we might
4119 // take a while to process their first tick).
4120 if (PeriodicTask::num_tasks() > 0) {
4121 WatcherThread::start();
4122 }
4123 }
4124
4125 create_vm_timer.end();
4126 #ifdef ASSERT
4127 _vm_complete = true;
4128 #endif
4129
4130 if (DumpSharedSpaces) {
4131 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
4132 ShouldNotReachHere();
4133 }
4134
4135 return JNI_OK;
4136 }
4137
4138 // type for the Agent_OnLoad and JVM_OnLoad entry points
4139 extern "C" {
4140 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
4141 }
4142 // Find a command line agent library and return its entry point for
4143 // -agentlib: -agentpath: -Xrun
4144 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
4145 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
4146 const char *on_load_symbols[],
4147 size_t num_symbol_entries) {
4148 OnLoadEntry_t on_load_entry = NULL;
4149 void *library = NULL;
4150
4151 if (!agent->valid()) {
4152 char buffer[JVM_MAXPATHLEN];
4153 char ebuf[1024] = "";
4154 const char *name = agent->name();
4155 const char *msg = "Could not find agent library ";
4156
4157 // First check to see if agent is statically linked into executable
4158 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
4159 library = agent->os_lib();
4160 } else if (agent->is_absolute_path()) {
4161 library = os::dll_load(name, ebuf, sizeof ebuf);
4162 if (library == NULL) {
4163 const char *sub_msg = " in absolute path, with error: ";
4164 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4165 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4166 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4167 // If we can't find the agent, exit.
4168 vm_exit_during_initialization(buf, NULL);
4169 FREE_C_HEAP_ARRAY(char, buf);
4170 }
4171 } else {
4172 // Try to load the agent from the standard dll directory
4173 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4174 name)) {
4175 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4176 }
4177 if (library == NULL) { // Try the library path directory.
4178 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4179 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4180 }
4181 if (library == NULL) {
4182 const char *sub_msg = " on the library path, with error: ";
4183 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4184
4185 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4186 strlen(ebuf) + strlen(sub_msg2) + 1;
4187 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4188 if (!agent->is_instrument_lib()) {
4189 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4190 } else {
4191 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4192 }
4193 // If we can't find the agent, exit.
4194 vm_exit_during_initialization(buf, NULL);
4195 FREE_C_HEAP_ARRAY(char, buf);
4196 }
4197 }
4198 }
4199 agent->set_os_lib(library);
4200 agent->set_valid();
4201 }
4202
4203 // Find the OnLoad function.
4204 on_load_entry =
4205 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4206 false,
4207 on_load_symbols,
4208 num_symbol_entries));
4209 return on_load_entry;
4210 }
4211
4212 // Find the JVM_OnLoad entry point
4213 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4214 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4215 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4216 }
4217
4218 // Find the Agent_OnLoad entry point
4219 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4220 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4221 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4222 }
4223
4224 // For backwards compatibility with -Xrun
4225 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4226 // treated like -agentpath:
4227 // Must be called before agent libraries are created
4228 void Threads::convert_vm_init_libraries_to_agents() {
4229 AgentLibrary* agent;
4230 AgentLibrary* next;
4231
4232 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4233 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4234 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4235
4236 // If there is an JVM_OnLoad function it will get called later,
4237 // otherwise see if there is an Agent_OnLoad
4238 if (on_load_entry == NULL) {
4239 on_load_entry = lookup_agent_on_load(agent);
4240 if (on_load_entry != NULL) {
4241 // switch it to the agent list -- so that Agent_OnLoad will be called,
4242 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4243 Arguments::convert_library_to_agent(agent);
4244 } else {
4245 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4246 }
4247 }
4248 }
4249 }
4250
4251 // Create agents for -agentlib: -agentpath: and converted -Xrun
4252 // Invokes Agent_OnLoad
4253 // Called very early -- before JavaThreads exist
4254 void Threads::create_vm_init_agents() {
4255 extern struct JavaVM_ main_vm;
4256 AgentLibrary* agent;
4257
4258 JvmtiExport::enter_onload_phase();
4259
4260 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4261 // CDS dumping does not support native JVMTI agent.
4262 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
4263 if (Arguments::is_dumping_archive()) {
4264 if(!agent->is_instrument_lib()) {
4265 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
4266 } else if (!AllowArchivingWithJavaAgent) {
4267 vm_exit_during_cds_dumping(
4268 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
4269 }
4270 }
4271
4272 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4273
4274 if (on_load_entry != NULL) {
4275 // Invoke the Agent_OnLoad function
4276 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4277 if (err != JNI_OK) {
4278 vm_exit_during_initialization("agent library failed to init", agent->name());
4279 }
4280 } else {
4281 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4282 }
4283 }
4284
4285 JvmtiExport::enter_primordial_phase();
4286 }
4287
4288 extern "C" {
4289 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4290 }
4291
4292 void Threads::shutdown_vm_agents() {
4293 // Send any Agent_OnUnload notifications
4294 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4295 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4296 extern struct JavaVM_ main_vm;
4297 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4298
4299 // Find the Agent_OnUnload function.
4300 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4301 os::find_agent_function(agent,
4302 false,
4303 on_unload_symbols,
4304 num_symbol_entries));
4305
4306 // Invoke the Agent_OnUnload function
4307 if (unload_entry != NULL) {
4308 JavaThread* thread = JavaThread::current();
4309 ThreadToNativeFromVM ttn(thread);
4310 HandleMark hm(thread);
4311 (*unload_entry)(&main_vm);
4312 }
4313 }
4314 }
4315
4316 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4317 // Invokes JVM_OnLoad
4318 void Threads::create_vm_init_libraries() {
4319 extern struct JavaVM_ main_vm;
4320 AgentLibrary* agent;
4321
4322 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4323 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4324
4325 if (on_load_entry != NULL) {
4326 // Invoke the JVM_OnLoad function
4327 JavaThread* thread = JavaThread::current();
4328 ThreadToNativeFromVM ttn(thread);
4329 HandleMark hm(thread);
4330 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4331 if (err != JNI_OK) {
4332 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4333 }
4334 } else {
4335 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4336 }
4337 }
4338 }
4339
4340
4341 // Last thread running calls java.lang.Shutdown.shutdown()
4342 void JavaThread::invoke_shutdown_hooks() {
4343 HandleMark hm(this);
4344
4345 // We could get here with a pending exception, if so clear it now.
4346 if (this->has_pending_exception()) {
4347 this->clear_pending_exception();
4348 }
4349
4350 EXCEPTION_MARK;
4351 Klass* shutdown_klass =
4352 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4353 THREAD);
4354 if (shutdown_klass != NULL) {
4355 // SystemDictionary::resolve_or_null will return null if there was
4356 // an exception. If we cannot load the Shutdown class, just don't
4357 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4358 // won't be run. Note that if a shutdown hook was registered,
4359 // the Shutdown class would have already been loaded
4360 // (Runtime.addShutdownHook will load it).
4361 JavaValue result(T_VOID);
4362 JavaCalls::call_static(&result,
4363 shutdown_klass,
4364 vmSymbols::shutdown_name(),
4365 vmSymbols::void_method_signature(),
4366 THREAD);
4367 }
4368 CLEAR_PENDING_EXCEPTION;
4369 }
4370
4371 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4372 // the program falls off the end of main(). Another VM exit path is through
4373 // vm_exit() when the program calls System.exit() to return a value or when
4374 // there is a serious error in VM. The two shutdown paths are not exactly
4375 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4376 // and VM_Exit op at VM level.
4377 //
4378 // Shutdown sequence:
4379 // + Shutdown native memory tracking if it is on
4380 // + Wait until we are the last non-daemon thread to execute
4381 // <-- every thing is still working at this moment -->
4382 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4383 // shutdown hooks
4384 // + Call before_exit(), prepare for VM exit
4385 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4386 // currently the only user of this mechanism is File.deleteOnExit())
4387 // > stop StatSampler, watcher thread,
4388 // post thread end and vm death events to JVMTI,
4389 // stop signal thread
4390 // + Call JavaThread::exit(), it will:
4391 // > release JNI handle blocks, remove stack guard pages
4392 // > remove this thread from Threads list
4393 // <-- no more Java code from this thread after this point -->
4394 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4395 // the compiler threads at safepoint
4396 // <-- do not use anything that could get blocked by Safepoint -->
4397 // + Disable tracing at JNI/JVM barriers
4398 // + Set _vm_exited flag for threads that are still running native code
4399 // + Call exit_globals()
4400 // > deletes tty
4401 // > deletes PerfMemory resources
4402 // + Delete this thread
4403 // + Return to caller
4404
4405 bool Threads::destroy_vm() {
4406 JavaThread* thread = JavaThread::current();
4407
4408 #ifdef ASSERT
4409 _vm_complete = false;
4410 #endif
4411 // Wait until we are the last non-daemon thread to execute
4412 { MonitorLocker nu(Threads_lock);
4413 while (Threads::number_of_non_daemon_threads() > 1)
4414 // This wait should make safepoint checks, wait without a timeout,
4415 // and wait as a suspend-equivalent condition.
4416 nu.wait(0, Mutex::_as_suspend_equivalent_flag);
4417 }
4418
4419 EventShutdown e;
4420 if (e.should_commit()) {
4421 e.set_reason("No remaining non-daemon Java threads");
4422 e.commit();
4423 }
4424
4425 // Hang forever on exit if we are reporting an error.
4426 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4427 os::infinite_sleep();
4428 }
4429 os::wait_for_keypress_at_exit();
4430
4431 // run Java level shutdown hooks
4432 thread->invoke_shutdown_hooks();
4433
4434 before_exit(thread);
4435
4436 thread->exit(true);
4437
4438 // Stop VM thread.
4439 {
4440 // 4945125 The vm thread comes to a safepoint during exit.
4441 // GC vm_operations can get caught at the safepoint, and the
4442 // heap is unparseable if they are caught. Grab the Heap_lock
4443 // to prevent this. The GC vm_operations will not be able to
4444 // queue until after the vm thread is dead. After this point,
4445 // we'll never emerge out of the safepoint before the VM exits.
4446
4447 MutexLocker ml(Heap_lock, Mutex::_no_safepoint_check_flag);
4448
4449 VMThread::wait_for_vm_thread_exit();
4450 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4451 VMThread::destroy();
4452 }
4453
4454 // Now, all Java threads are gone except daemon threads. Daemon threads
4455 // running Java code or in VM are stopped by the Safepoint. However,
4456 // daemon threads executing native code are still running. But they
4457 // will be stopped at native=>Java/VM barriers. Note that we can't
4458 // simply kill or suspend them, as it is inherently deadlock-prone.
4459
4460 VM_Exit::set_vm_exited();
4461
4462 // Clean up ideal graph printers after the VMThread has started
4463 // the final safepoint which will block all the Compiler threads.
4464 // Note that this Thread has already logically exited so the
4465 // clean_up() function's use of a JavaThreadIteratorWithHandle
4466 // would be a problem except set_vm_exited() has remembered the
4467 // shutdown thread which is granted a policy exception.
4468 #if defined(COMPILER2) && !defined(PRODUCT)
4469 IdealGraphPrinter::clean_up();
4470 #endif
4471
4472 notify_vm_shutdown();
4473
4474 // exit_globals() will delete tty
4475 exit_globals();
4476
4477 // We are after VM_Exit::set_vm_exited() so we can't call
4478 // thread->smr_delete() or we will block on the Threads_lock.
4479 // Deleting the shutdown thread here is safe because another
4480 // JavaThread cannot have an active ThreadsListHandle for
4481 // this JavaThread.
4482 delete thread;
4483
4484 #if INCLUDE_JVMCI
4485 if (JVMCICounterSize > 0) {
4486 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4487 }
4488 #endif
4489
4490 LogConfiguration::finalize();
4491
4492 return true;
4493 }
4494
4495
4496 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4497 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4498 return is_supported_jni_version(version);
4499 }
4500
4501
4502 jboolean Threads::is_supported_jni_version(jint version) {
4503 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4504 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4505 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4506 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4507 if (version == JNI_VERSION_9) return JNI_TRUE;
4508 if (version == JNI_VERSION_10) return JNI_TRUE;
4509 return JNI_FALSE;
4510 }
4511
4512
4513 void Threads::add(JavaThread* p, bool force_daemon) {
4514 // The threads lock must be owned at this point
4515 assert(Threads_lock->owned_by_self(), "must have threads lock");
4516
4517 BarrierSet::barrier_set()->on_thread_attach(p);
4518
4519 // Once a JavaThread is added to the Threads list, smr_delete() has
4520 // to be used to delete it. Otherwise we can just delete it directly.
4521 p->set_on_thread_list();
4522
4523 _number_of_threads++;
4524 oop threadObj = p->threadObj();
4525 bool daemon = true;
4526 // Bootstrapping problem: threadObj can be null for initial
4527 // JavaThread (or for threads attached via JNI)
4528 if ((!force_daemon) && !is_daemon((threadObj))) {
4529 _number_of_non_daemon_threads++;
4530 daemon = false;
4531 }
4532
4533 ThreadService::add_thread(p, daemon);
4534
4535 // Maintain fast thread list
4536 ThreadsSMRSupport::add_thread(p);
4537
4538 // Possible GC point.
4539 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4540 }
4541
4542 void Threads::remove(JavaThread* p, bool is_daemon) {
4543
4544 // Reclaim the ObjectMonitors from the om_in_use_list and om_free_list of the moribund thread.
4545 ObjectSynchronizer::om_flush(p);
4546
4547 // Extra scope needed for Thread_lock, so we can check
4548 // that we do not remove thread without safepoint code notice
4549 { MonitorLocker ml(Threads_lock);
4550
4551 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4552
4553 // Maintain fast thread list
4554 ThreadsSMRSupport::remove_thread(p);
4555
4556 _number_of_threads--;
4557 if (!is_daemon) {
4558 _number_of_non_daemon_threads--;
4559
4560 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4561 // on destroy_vm will wake up.
4562 if (number_of_non_daemon_threads() == 1) {
4563 ml.notify_all();
4564 }
4565 }
4566 ThreadService::remove_thread(p, is_daemon);
4567
4568 // Make sure that safepoint code disregard this thread. This is needed since
4569 // the thread might mess around with locks after this point. This can cause it
4570 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4571 // of this thread since it is removed from the queue.
4572 p->set_terminated_value();
4573 } // unlock Threads_lock
4574
4575 // Since Events::log uses a lock, we grab it outside the Threads_lock
4576 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4577 }
4578
4579 // Operations on the Threads list for GC. These are not explicitly locked,
4580 // but the garbage collector must provide a safe context for them to run.
4581 // In particular, these things should never be called when the Threads_lock
4582 // is held by some other thread. (Note: the Safepoint abstraction also
4583 // uses the Threads_lock to guarantee this property. It also makes sure that
4584 // all threads gets blocked when exiting or starting).
4585
4586 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4587 ALL_JAVA_THREADS(p) {
4588 p->oops_do(f, cf);
4589 }
4590 VMThread::vm_thread()->oops_do(f, cf);
4591 }
4592
4593 void Threads::change_thread_claim_token() {
4594 if (++_thread_claim_token == 0) {
4595 // On overflow of the token counter, there is a risk of future
4596 // collisions between a new global token value and a stale token
4597 // for a thread, because not all iterations visit all threads.
4598 // (Though it's pretty much a theoretical concern for non-trivial
4599 // token counter sizes.) To deal with the possibility, reset all
4600 // the thread tokens to zero on global token overflow.
4601 struct ResetClaims : public ThreadClosure {
4602 virtual void do_thread(Thread* t) {
4603 t->claim_threads_do(false, 0);
4604 }
4605 } reset_claims;
4606 Threads::threads_do(&reset_claims);
4607 // On overflow, update the global token to non-zero, to
4608 // avoid the special "never claimed" initial thread value.
4609 _thread_claim_token = 1;
4610 }
4611 }
4612
4613 #ifdef ASSERT
4614 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
4615 const uintx token = t->threads_do_token();
4616 assert(token == expected,
4617 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
4618 UINTX_FORMAT, kind, p2i(t), token, expected);
4619 }
4620
4621 void Threads::assert_all_threads_claimed() {
4622 ALL_JAVA_THREADS(p) {
4623 assert_thread_claimed("Thread", p, _thread_claim_token);
4624 }
4625 assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token);
4626 }
4627 #endif // ASSERT
4628
4629 class ParallelOopsDoThreadClosure : public ThreadClosure {
4630 private:
4631 OopClosure* _f;
4632 CodeBlobClosure* _cf;
4633 public:
4634 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4635 void do_thread(Thread* t) {
4636 t->oops_do(_f, _cf);
4637 }
4638 };
4639
4640 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4641 ParallelOopsDoThreadClosure tc(f, cf);
4642 possibly_parallel_threads_do(is_par, &tc);
4643 }
4644
4645 void Threads::nmethods_do(CodeBlobClosure* cf) {
4646 ALL_JAVA_THREADS(p) {
4647 // This is used by the code cache sweeper to mark nmethods that are active
4648 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4649 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4650 if(!p->is_Code_cache_sweeper_thread()) {
4651 p->nmethods_do(cf);
4652 }
4653 }
4654 }
4655
4656 void Threads::metadata_do(MetadataClosure* f) {
4657 ALL_JAVA_THREADS(p) {
4658 p->metadata_do(f);
4659 }
4660 }
4661
4662 class ThreadHandlesClosure : public ThreadClosure {
4663 void (*_f)(Metadata*);
4664 public:
4665 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4666 virtual void do_thread(Thread* thread) {
4667 thread->metadata_handles_do(_f);
4668 }
4669 };
4670
4671 void Threads::metadata_handles_do(void f(Metadata*)) {
4672 // Only walk the Handles in Thread.
4673 ThreadHandlesClosure handles_closure(f);
4674 threads_do(&handles_closure);
4675 }
4676
4677 // Get count Java threads that are waiting to enter the specified monitor.
4678 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4679 int count,
4680 address monitor) {
4681 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4682
4683 int i = 0;
4684 DO_JAVA_THREADS(t_list, p) {
4685 if (!p->can_call_java()) continue;
4686
4687 address pending = (address)p->current_pending_monitor();
4688 if (pending == monitor) { // found a match
4689 if (i < count) result->append(p); // save the first count matches
4690 i++;
4691 }
4692 }
4693
4694 return result;
4695 }
4696
4697
4698 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4699 address owner) {
4700 // NULL owner means not locked so we can skip the search
4701 if (owner == NULL) return NULL;
4702
4703 DO_JAVA_THREADS(t_list, p) {
4704 // first, see if owner is the address of a Java thread
4705 if (owner == (address)p) return p;
4706 }
4707
4708 // Cannot assert on lack of success here since this function may be
4709 // used by code that is trying to report useful problem information
4710 // like deadlock detection.
4711 if (UseHeavyMonitors) return NULL;
4712
4713 // If we didn't find a matching Java thread and we didn't force use of
4714 // heavyweight monitors, then the owner is the stack address of the
4715 // Lock Word in the owning Java thread's stack.
4716 //
4717 JavaThread* the_owner = NULL;
4718 DO_JAVA_THREADS(t_list, q) {
4719 if (q->is_lock_owned(owner)) {
4720 the_owner = q;
4721 break;
4722 }
4723 }
4724
4725 // cannot assert on lack of success here; see above comment
4726 return the_owner;
4727 }
4728
4729 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4730 void Threads::print_on(outputStream* st, bool print_stacks,
4731 bool internal_format, bool print_concurrent_locks,
4732 bool print_extended_info) {
4733 char buf[32];
4734 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4735
4736 st->print_cr("Full thread dump %s (%s %s):",
4737 VM_Version::vm_name(),
4738 VM_Version::vm_release(),
4739 VM_Version::vm_info_string());
4740 st->cr();
4741
4742 #if INCLUDE_SERVICES
4743 // Dump concurrent locks
4744 ConcurrentLocksDump concurrent_locks;
4745 if (print_concurrent_locks) {
4746 concurrent_locks.dump_at_safepoint();
4747 }
4748 #endif // INCLUDE_SERVICES
4749
4750 ThreadsSMRSupport::print_info_on(st);
4751 st->cr();
4752
4753 ALL_JAVA_THREADS(p) {
4754 ResourceMark rm;
4755 p->print_on(st, print_extended_info);
4756 if (print_stacks) {
4757 if (internal_format) {
4758 p->trace_stack();
4759 } else {
4760 p->print_stack_on(st);
4761 }
4762 }
4763 st->cr();
4764 #if INCLUDE_SERVICES
4765 if (print_concurrent_locks) {
4766 concurrent_locks.print_locks_on(p, st);
4767 }
4768 #endif // INCLUDE_SERVICES
4769 }
4770
4771 VMThread::vm_thread()->print_on(st);
4772 st->cr();
4773 Universe::heap()->print_gc_threads_on(st);
4774 WatcherThread* wt = WatcherThread::watcher_thread();
4775 if (wt != NULL) {
4776 wt->print_on(st);
4777 st->cr();
4778 }
4779
4780 st->flush();
4781 }
4782
4783 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4784 int buflen, bool* found_current) {
4785 if (this_thread != NULL) {
4786 bool is_current = (current == this_thread);
4787 *found_current = *found_current || is_current;
4788 st->print("%s", is_current ? "=>" : " ");
4789
4790 st->print(PTR_FORMAT, p2i(this_thread));
4791 st->print(" ");
4792 this_thread->print_on_error(st, buf, buflen);
4793 st->cr();
4794 }
4795 }
4796
4797 class PrintOnErrorClosure : public ThreadClosure {
4798 outputStream* _st;
4799 Thread* _current;
4800 char* _buf;
4801 int _buflen;
4802 bool* _found_current;
4803 public:
4804 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4805 int buflen, bool* found_current) :
4806 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4807
4808 virtual void do_thread(Thread* thread) {
4809 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4810 }
4811 };
4812
4813 // Threads::print_on_error() is called by fatal error handler. It's possible
4814 // that VM is not at safepoint and/or current thread is inside signal handler.
4815 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4816 // memory (even in resource area), it might deadlock the error handler.
4817 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4818 int buflen) {
4819 ThreadsSMRSupport::print_info_on(st);
4820 st->cr();
4821
4822 bool found_current = false;
4823 st->print_cr("Java Threads: ( => current thread )");
4824 ALL_JAVA_THREADS(thread) {
4825 print_on_error(thread, st, current, buf, buflen, &found_current);
4826 }
4827 st->cr();
4828
4829 st->print_cr("Other Threads:");
4830 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4831 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4832
4833 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4834 Universe::heap()->gc_threads_do(&print_closure);
4835
4836 if (!found_current) {
4837 st->cr();
4838 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4839 current->print_on_error(st, buf, buflen);
4840 st->cr();
4841 }
4842 st->cr();
4843
4844 st->print_cr("Threads with active compile tasks:");
4845 print_threads_compiling(st, buf, buflen);
4846 }
4847
4848 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
4849 ALL_JAVA_THREADS(thread) {
4850 if (thread->is_Compiler_thread()) {
4851 CompilerThread* ct = (CompilerThread*) thread;
4852
4853 // Keep task in local variable for NULL check.
4854 // ct->_task might be set to NULL by concurring compiler thread
4855 // because it completed the compilation. The task is never freed,
4856 // though, just returned to a free list.
4857 CompileTask* task = ct->task();
4858 if (task != NULL) {
4859 thread->print_name_on_error(st, buf, buflen);
4860 st->print(" ");
4861 task->print(st, NULL, short_form, true);
4862 }
4863 }
4864 }
4865 }
4866
4867
4868 // Internal SpinLock and Mutex
4869 // Based on ParkEvent
4870
4871 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4872 //
4873 // We employ SpinLocks _only for low-contention, fixed-length
4874 // short-duration critical sections where we're concerned
4875 // about native mutex_t or HotSpot Mutex:: latency.
4876 // The mux construct provides a spin-then-block mutual exclusion
4877 // mechanism.
4878 //
4879 // Testing has shown that contention on the ListLock guarding gFreeList
4880 // is common. If we implement ListLock as a simple SpinLock it's common
4881 // for the JVM to devolve to yielding with little progress. This is true
4882 // despite the fact that the critical sections protected by ListLock are
4883 // extremely short.
4884 //
4885 // TODO-FIXME: ListLock should be of type SpinLock.
4886 // We should make this a 1st-class type, integrated into the lock
4887 // hierarchy as leaf-locks. Critically, the SpinLock structure
4888 // should have sufficient padding to avoid false-sharing and excessive
4889 // cache-coherency traffic.
4890
4891
4892 typedef volatile int SpinLockT;
4893
4894 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4895 if (Atomic::cmpxchg(adr, 0, 1) == 0) {
4896 return; // normal fast-path return
4897 }
4898
4899 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4900 int ctr = 0;
4901 int Yields = 0;
4902 for (;;) {
4903 while (*adr != 0) {
4904 ++ctr;
4905 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4906 if (Yields > 5) {
4907 os::naked_short_sleep(1);
4908 } else {
4909 os::naked_yield();
4910 ++Yields;
4911 }
4912 } else {
4913 SpinPause();
4914 }
4915 }
4916 if (Atomic::cmpxchg(adr, 0, 1) == 0) return;
4917 }
4918 }
4919
4920 void Thread::SpinRelease(volatile int * adr) {
4921 assert(*adr != 0, "invariant");
4922 OrderAccess::fence(); // guarantee at least release consistency.
4923 // Roach-motel semantics.
4924 // It's safe if subsequent LDs and STs float "up" into the critical section,
4925 // but prior LDs and STs within the critical section can't be allowed
4926 // to reorder or float past the ST that releases the lock.
4927 // Loads and stores in the critical section - which appear in program
4928 // order before the store that releases the lock - must also appear
4929 // before the store that releases the lock in memory visibility order.
4930 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4931 // the ST of 0 into the lock-word which releases the lock, so fence
4932 // more than covers this on all platforms.
4933 *adr = 0;
4934 }
4935
4936 // muxAcquire and muxRelease:
4937 //
4938 // * muxAcquire and muxRelease support a single-word lock-word construct.
4939 // The LSB of the word is set IFF the lock is held.
4940 // The remainder of the word points to the head of a singly-linked list
4941 // of threads blocked on the lock.
4942 //
4943 // * The current implementation of muxAcquire-muxRelease uses its own
4944 // dedicated Thread._MuxEvent instance. If we're interested in
4945 // minimizing the peak number of extant ParkEvent instances then
4946 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4947 // as certain invariants were satisfied. Specifically, care would need
4948 // to be taken with regards to consuming unpark() "permits".
4949 // A safe rule of thumb is that a thread would never call muxAcquire()
4950 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4951 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4952 // consume an unpark() permit intended for monitorenter, for instance.
4953 // One way around this would be to widen the restricted-range semaphore
4954 // implemented in park(). Another alternative would be to provide
4955 // multiple instances of the PlatformEvent() for each thread. One
4956 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4957 //
4958 // * Usage:
4959 // -- Only as leaf locks
4960 // -- for short-term locking only as muxAcquire does not perform
4961 // thread state transitions.
4962 //
4963 // Alternatives:
4964 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4965 // but with parking or spin-then-park instead of pure spinning.
4966 // * Use Taura-Oyama-Yonenzawa locks.
4967 // * It's possible to construct a 1-0 lock if we encode the lockword as
4968 // (List,LockByte). Acquire will CAS the full lockword while Release
4969 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4970 // acquiring threads use timers (ParkTimed) to detect and recover from
4971 // the stranding window. Thread/Node structures must be aligned on 256-byte
4972 // boundaries by using placement-new.
4973 // * Augment MCS with advisory back-link fields maintained with CAS().
4974 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4975 // The validity of the backlinks must be ratified before we trust the value.
4976 // If the backlinks are invalid the exiting thread must back-track through the
4977 // the forward links, which are always trustworthy.
4978 // * Add a successor indication. The LockWord is currently encoded as
4979 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4980 // to provide the usual futile-wakeup optimization.
4981 // See RTStt for details.
4982 //
4983
4984
4985 const intptr_t LOCKBIT = 1;
4986
4987 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4988 intptr_t w = Atomic::cmpxchg(Lock, (intptr_t)0, LOCKBIT);
4989 if (w == 0) return;
4990 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) {
4991 return;
4992 }
4993
4994 ParkEvent * const Self = Thread::current()->_MuxEvent;
4995 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4996 for (;;) {
4997 int its = (os::is_MP() ? 100 : 0) + 1;
4998
4999 // Optional spin phase: spin-then-park strategy
5000 while (--its >= 0) {
5001 w = *Lock;
5002 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) {
5003 return;
5004 }
5005 }
5006
5007 Self->reset();
5008 Self->OnList = intptr_t(Lock);
5009 // The following fence() isn't _strictly necessary as the subsequent
5010 // CAS() both serializes execution and ratifies the fetched *Lock value.
5011 OrderAccess::fence();
5012 for (;;) {
5013 w = *Lock;
5014 if ((w & LOCKBIT) == 0) {
5015 if (Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) {
5016 Self->OnList = 0; // hygiene - allows stronger asserts
5017 return;
5018 }
5019 continue; // Interference -- *Lock changed -- Just retry
5020 }
5021 assert(w & LOCKBIT, "invariant");
5022 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
5023 if (Atomic::cmpxchg(Lock, w, intptr_t(Self)|LOCKBIT) == w) break;
5024 }
5025
5026 while (Self->OnList != 0) {
5027 Self->park();
5028 }
5029 }
5030 }
5031
5032 // Release() must extract a successor from the list and then wake that thread.
5033 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
5034 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
5035 // Release() would :
5036 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
5037 // (B) Extract a successor from the private list "in-hand"
5038 // (C) attempt to CAS() the residual back into *Lock over null.
5039 // If there were any newly arrived threads and the CAS() would fail.
5040 // In that case Release() would detach the RATs, re-merge the list in-hand
5041 // with the RATs and repeat as needed. Alternately, Release() might
5042 // detach and extract a successor, but then pass the residual list to the wakee.
5043 // The wakee would be responsible for reattaching and remerging before it
5044 // competed for the lock.
5045 //
5046 // Both "pop" and DMR are immune from ABA corruption -- there can be
5047 // multiple concurrent pushers, but only one popper or detacher.
5048 // This implementation pops from the head of the list. This is unfair,
5049 // but tends to provide excellent throughput as hot threads remain hot.
5050 // (We wake recently run threads first).
5051 //
5052 // All paths through muxRelease() will execute a CAS.
5053 // Release consistency -- We depend on the CAS in muxRelease() to provide full
5054 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
5055 // executed within the critical section are complete and globally visible before the
5056 // store (CAS) to the lock-word that releases the lock becomes globally visible.
5057 void Thread::muxRelease(volatile intptr_t * Lock) {
5058 for (;;) {
5059 const intptr_t w = Atomic::cmpxchg(Lock, LOCKBIT, (intptr_t)0);
5060 assert(w & LOCKBIT, "invariant");
5061 if (w == LOCKBIT) return;
5062 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
5063 assert(List != NULL, "invariant");
5064 assert(List->OnList == intptr_t(Lock), "invariant");
5065 ParkEvent * const nxt = List->ListNext;
5066 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5067
5068 // The following CAS() releases the lock and pops the head element.
5069 // The CAS() also ratifies the previously fetched lock-word value.
5070 if (Atomic::cmpxchg(Lock, w, intptr_t(nxt)) != w) {
5071 continue;
5072 }
5073 List->OnList = 0;
5074 OrderAccess::fence();
5075 List->unpark();
5076 return;
5077 }
5078 }
5079
5080
5081 void Threads::verify() {
5082 ALL_JAVA_THREADS(p) {
5083 p->verify();
5084 }
5085 VMThread* thread = VMThread::vm_thread();
5086 if (thread != NULL) thread->verify();
5087 }