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