1 /*
2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classLoader.hpp"
29 #include "classfile/javaClasses.hpp"
30 #include "classfile/moduleEntry.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "code/codeCache.hpp"
34 #include "code/scopeDesc.hpp"
35 #include "compiler/compileBroker.hpp"
36 #include "compiler/compileTask.hpp"
37 #include "gc/shared/barrierSet.hpp"
38 #include "gc/shared/gcId.hpp"
39 #include "gc/shared/gcLocker.inline.hpp"
40 #include "gc/shared/workgroup.hpp"
41 #include "interpreter/interpreter.hpp"
42 #include "interpreter/linkResolver.hpp"
43 #include "interpreter/oopMapCache.hpp"
44 #include "jfr/jfrEvents.hpp"
45 #include "jvmtifiles/jvmtiEnv.hpp"
46 #include "logging/log.hpp"
47 #include "logging/logConfiguration.hpp"
48 #include "logging/logStream.hpp"
49 #include "memory/allocation.inline.hpp"
50 #include "memory/iterator.hpp"
51 #include "memory/metaspaceShared.hpp"
52 #include "memory/oopFactory.hpp"
53 #include "memory/resourceArea.hpp"
54 #include "memory/universe.hpp"
55 #include "oops/access.inline.hpp"
56 #include "oops/instanceKlass.hpp"
57 #include "oops/objArrayOop.hpp"
58 #include "oops/oop.inline.hpp"
59 #include "oops/symbol.hpp"
60 #include "oops/typeArrayOop.inline.hpp"
61 #include "oops/verifyOopClosure.hpp"
62 #include "prims/jvm_misc.hpp"
63 #include "prims/jvmtiExport.hpp"
64 #include "prims/jvmtiThreadState.hpp"
65 #include "runtime/arguments.hpp"
66 #include "runtime/atomic.hpp"
67 #include "runtime/biasedLocking.hpp"
68 #include "runtime/fieldDescriptor.inline.hpp"
69 #include "runtime/flags/jvmFlagConstraintList.hpp"
70 #include "runtime/flags/jvmFlagRangeList.hpp"
71 #include "runtime/deoptimization.hpp"
72 #include "runtime/frame.inline.hpp"
73 #include "runtime/handles.inline.hpp"
74 #include "runtime/handshake.hpp"
75 #include "runtime/init.hpp"
76 #include "runtime/interfaceSupport.inline.hpp"
77 #include "runtime/java.hpp"
78 #include "runtime/javaCalls.hpp"
79 #include "runtime/jniHandles.inline.hpp"
80 #include "runtime/jniPeriodicChecker.hpp"
81 #include "runtime/memprofiler.hpp"
82 #include "runtime/mutexLocker.hpp"
83 #include "runtime/objectMonitor.hpp"
84 #include "runtime/orderAccess.hpp"
85 #include "runtime/osThread.hpp"
86 #include "runtime/prefetch.inline.hpp"
87 #include "runtime/safepoint.hpp"
88 #include "runtime/safepointMechanism.inline.hpp"
89 #include "runtime/safepointVerifiers.hpp"
90 #include "runtime/serviceThread.hpp"
91 #include "runtime/sharedRuntime.hpp"
92 #include "runtime/statSampler.hpp"
93 #include "runtime/stubRoutines.hpp"
94 #include "runtime/sweeper.hpp"
95 #include "runtime/task.hpp"
96 #include "runtime/thread.inline.hpp"
97 #include "runtime/threadCritical.hpp"
98 #include "runtime/threadSMR.inline.hpp"
99 #include "runtime/threadStatisticalInfo.hpp"
100 #include "runtime/timer.hpp"
101 #include "runtime/timerTrace.hpp"
102 #include "runtime/vframe.inline.hpp"
103 #include "runtime/vframeArray.hpp"
104 #include "runtime/vframe_hp.hpp"
105 #include "runtime/vmThread.hpp"
106 #include "runtime/vmOperations.hpp"
107 #include "runtime/vm_version.hpp"
108 #include "services/attachListener.hpp"
109 #include "services/management.hpp"
110 #include "services/memTracker.hpp"
111 #include "services/threadService.hpp"
112 #include "utilities/align.hpp"
113 #include "utilities/copy.hpp"
114 #include "utilities/defaultStream.hpp"
115 #include "utilities/dtrace.hpp"
116 #include "utilities/events.hpp"
117 #include "utilities/macros.hpp"
118 #include "utilities/preserveException.hpp"
119 #include "utilities/singleWriterSynchronizer.hpp"
120 #include "utilities/vmError.hpp"
121 #if INCLUDE_JVMCI
122 #include "jvmci/jvmci.hpp"
123 #include "jvmci/jvmciEnv.hpp"
124 #endif
125 #ifdef COMPILER1
126 #include "c1/c1_Compiler.hpp"
127 #endif
128 #ifdef COMPILER2
129 #include "opto/c2compiler.hpp"
130 #include "opto/idealGraphPrinter.hpp"
131 #endif
132 #if INCLUDE_RTM_OPT
133 #include "runtime/rtmLocking.hpp"
134 #endif
135 #if INCLUDE_JFR
136 #include "jfr/jfr.hpp"
137 #endif
138
139 // Initialization after module runtime initialization
140 void universe_post_module_init(); // must happen after call_initPhase2
141
142 #ifdef DTRACE_ENABLED
143
144 // Only bother with this argument setup if dtrace is available
145
146 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
147 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
148
149 #define DTRACE_THREAD_PROBE(probe, javathread) \
150 { \
151 ResourceMark rm(this); \
152 int len = 0; \
153 const char* name = (javathread)->get_thread_name(); \
154 len = strlen(name); \
155 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
156 (char *) name, len, \
157 java_lang_Thread::thread_id((javathread)->threadObj()), \
158 (uintptr_t) (javathread)->osthread()->thread_id(), \
159 java_lang_Thread::is_daemon((javathread)->threadObj())); \
160 }
161
162 #else // ndef DTRACE_ENABLED
163
164 #define DTRACE_THREAD_PROBE(probe, javathread)
165
166 #endif // ndef DTRACE_ENABLED
167
168 #ifndef USE_LIBRARY_BASED_TLS_ONLY
169 // Current thread is maintained as a thread-local variable
170 THREAD_LOCAL Thread* Thread::_thr_current = NULL;
171 #endif
172
173 // ======= Thread ========
174 // Support for forcing alignment of thread objects for biased locking
175 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
176 if (UseBiasedLocking) {
177 const size_t alignment = markWord::biased_lock_alignment;
178 size_t aligned_size = size + (alignment - sizeof(intptr_t));
179 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
180 : AllocateHeap(aligned_size, flags, CURRENT_PC,
181 AllocFailStrategy::RETURN_NULL);
182 void* aligned_addr = align_up(real_malloc_addr, alignment);
183 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
184 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
185 "JavaThread alignment code overflowed allocated storage");
186 if (aligned_addr != real_malloc_addr) {
187 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
188 p2i(real_malloc_addr),
189 p2i(aligned_addr));
190 }
191 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
192 return aligned_addr;
193 } else {
194 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
195 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
196 }
197 }
198
199 void Thread::operator delete(void* p) {
200 if (UseBiasedLocking) {
201 FreeHeap(((Thread*) p)->_real_malloc_address);
202 } else {
203 FreeHeap(p);
204 }
205 }
206
207 void JavaThread::smr_delete() {
208 if (_on_thread_list) {
209 ThreadsSMRSupport::smr_delete(this);
210 } else {
211 delete this;
212 }
213 }
214
215 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
216 // JavaThread
217
218 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
219
220 Thread::Thread() {
221
222 DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
223
224 // stack and get_thread
225 set_stack_base(NULL);
226 set_stack_size(0);
227 set_lgrp_id(-1);
228 DEBUG_ONLY(clear_suspendible_thread();)
229
230 // allocated data structures
231 set_osthread(NULL);
232 set_resource_area(new (mtThread)ResourceArea());
233 DEBUG_ONLY(_current_resource_mark = NULL;)
234 set_handle_area(new (mtThread) HandleArea(NULL));
235 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
236 set_active_handles(NULL);
237 set_free_handle_block(NULL);
238 set_last_handle_mark(NULL);
239 DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
240
241 // Initial value of zero ==> never claimed.
242 _threads_do_token = 0;
243 _threads_hazard_ptr = NULL;
244 _threads_list_ptr = NULL;
245 _nested_threads_hazard_ptr_cnt = 0;
246 _rcu_counter = 0;
247
248 // the handle mark links itself to last_handle_mark
249 new HandleMark(this);
250
251 // plain initialization
252 debug_only(_owned_locks = NULL;)
253 NOT_PRODUCT(_no_safepoint_count = 0;)
254 NOT_PRODUCT(_skip_gcalot = false;)
255 _jvmti_env_iteration_count = 0;
256 set_allocated_bytes(0);
257 _vm_operation_started_count = 0;
258 _vm_operation_completed_count = 0;
259 _current_pending_monitor = NULL;
260 _current_pending_monitor_is_from_java = true;
261 _current_waiting_monitor = NULL;
262 _current_pending_raw_monitor = NULL;
263 _num_nested_signal = 0;
264 om_free_list = NULL;
265 om_free_count = 0;
266 om_free_provision = 32;
267 om_in_use_list = NULL;
268 om_in_use_count = 0;
269
270 #ifdef ASSERT
271 _visited_for_critical_count = false;
272 #endif
273
274 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
275 Monitor::_safepoint_check_sometimes);
276 _suspend_flags = 0;
277
278 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
279 _hashStateX = os::random();
280 _hashStateY = 842502087;
281 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
282 _hashStateW = 273326509;
283
284 _OnTrap = 0;
285 _Stalled = 0;
286 _TypeTag = 0x2BAD;
287
288 // Many of the following fields are effectively final - immutable
289 // Note that nascent threads can't use the Native Monitor-Mutex
290 // construct until the _MutexEvent is initialized ...
291 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
292 // we might instead use a stack of ParkEvents that we could provision on-demand.
293 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
294 // and ::Release()
295 _ParkEvent = ParkEvent::Allocate(this);
296 _MuxEvent = ParkEvent::Allocate(this);
297
298 #ifdef CHECK_UNHANDLED_OOPS
299 if (CheckUnhandledOops) {
300 _unhandled_oops = new UnhandledOops(this);
301 }
302 #endif // CHECK_UNHANDLED_OOPS
303 #ifdef ASSERT
304 if (UseBiasedLocking) {
305 assert(is_aligned(this, markWord::biased_lock_alignment), "forced alignment of thread object failed");
306 assert(this == _real_malloc_address ||
307 this == align_up(_real_malloc_address, markWord::biased_lock_alignment),
308 "bug in forced alignment of thread objects");
309 }
310 #endif // ASSERT
311
312 // Notify the barrier set that a thread is being created. The initial
313 // thread is created before the barrier set is available. The call to
314 // BarrierSet::on_thread_create() for this thread is therefore deferred
315 // to BarrierSet::set_barrier_set().
316 BarrierSet* const barrier_set = BarrierSet::barrier_set();
317 if (barrier_set != NULL) {
318 barrier_set->on_thread_create(this);
319 } else {
320 // Only the main thread should be created before the barrier set
321 // and that happens just before Thread::current is set. No other thread
322 // can attach as the VM is not created yet, so they can't execute this code.
323 // If the main thread creates other threads before the barrier set that is an error.
324 assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
325 }
326 }
327
328 void Thread::initialize_thread_current() {
329 #ifndef USE_LIBRARY_BASED_TLS_ONLY
330 assert(_thr_current == NULL, "Thread::current already initialized");
331 _thr_current = this;
332 #endif
333 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
334 ThreadLocalStorage::set_thread(this);
335 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
336 }
337
338 void Thread::clear_thread_current() {
339 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
340 #ifndef USE_LIBRARY_BASED_TLS_ONLY
341 _thr_current = NULL;
342 #endif
343 ThreadLocalStorage::set_thread(NULL);
344 }
345
346 void Thread::record_stack_base_and_size() {
347 // Note: at this point, Thread object is not yet initialized. Do not rely on
348 // any members being initialized. Do not rely on Thread::current() being set.
349 // If possible, refrain from doing anything which may crash or assert since
350 // quite probably those crash dumps will be useless.
351 set_stack_base(os::current_stack_base());
352 set_stack_size(os::current_stack_size());
353
354 #ifdef SOLARIS
355 if (os::is_primordial_thread()) {
356 os::Solaris::correct_stack_boundaries_for_primordial_thread(this);
357 }
358 #endif
359
360 // Set stack limits after thread is initialized.
361 if (is_Java_thread()) {
362 ((JavaThread*) this)->set_stack_overflow_limit();
363 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
364 }
365 }
366
367 #if INCLUDE_NMT
368 void Thread::register_thread_stack_with_NMT() {
369 MemTracker::record_thread_stack(stack_end(), stack_size());
370 }
371 #endif // INCLUDE_NMT
372
373 void Thread::call_run() {
374 DEBUG_ONLY(_run_state = CALL_RUN;)
375
376 // At this point, Thread object should be fully initialized and
377 // Thread::current() should be set.
378
379 assert(Thread::current_or_null() != NULL, "current thread is unset");
380 assert(Thread::current_or_null() == this, "current thread is wrong");
381
382 // Perform common initialization actions
383
384 register_thread_stack_with_NMT();
385
386 JFR_ONLY(Jfr::on_thread_start(this);)
387
388 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
389 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
390 os::current_thread_id(), p2i(stack_end()),
391 p2i(stack_base()), stack_size()/1024);
392
393 // Perform <ChildClass> initialization actions
394 DEBUG_ONLY(_run_state = PRE_RUN;)
395 this->pre_run();
396
397 // Invoke <ChildClass>::run()
398 DEBUG_ONLY(_run_state = RUN;)
399 this->run();
400 // Returned from <ChildClass>::run(). Thread finished.
401
402 // Perform common tear-down actions
403
404 assert(Thread::current_or_null() != NULL, "current thread is unset");
405 assert(Thread::current_or_null() == this, "current thread is wrong");
406
407 // Perform <ChildClass> tear-down actions
408 DEBUG_ONLY(_run_state = POST_RUN;)
409 this->post_run();
410
411 // Note: at this point the thread object may already have deleted itself,
412 // so from here on do not dereference *this*. Not all thread types currently
413 // delete themselves when they terminate. But no thread should ever be deleted
414 // asynchronously with respect to its termination - that is what _run_state can
415 // be used to check.
416
417 assert(Thread::current_or_null() == NULL, "current thread still present");
418 }
419
420 Thread::~Thread() {
421
422 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
423 // get started due to errors etc. Any active thread should at least reach post_run
424 // before it is deleted (usually in post_run()).
425 assert(_run_state == PRE_CALL_RUN ||
426 _run_state == POST_RUN, "Active Thread deleted before post_run(): "
427 "_run_state=%d", (int)_run_state);
428
429 // Notify the barrier set that a thread is being destroyed. Note that a barrier
430 // set might not be available if we encountered errors during bootstrapping.
431 BarrierSet* const barrier_set = BarrierSet::barrier_set();
432 if (barrier_set != NULL) {
433 barrier_set->on_thread_destroy(this);
434 }
435
436 // stack_base can be NULL if the thread is never started or exited before
437 // record_stack_base_and_size called. Although, we would like to ensure
438 // that all started threads do call record_stack_base_and_size(), there is
439 // not proper way to enforce that.
440 #if INCLUDE_NMT
441 if (_stack_base != NULL) {
442 MemTracker::release_thread_stack(stack_end(), stack_size());
443 #ifdef ASSERT
444 set_stack_base(NULL);
445 #endif
446 }
447 #endif // INCLUDE_NMT
448
449 // deallocate data structures
450 delete resource_area();
451 // since the handle marks are using the handle area, we have to deallocated the root
452 // handle mark before deallocating the thread's handle area,
453 assert(last_handle_mark() != NULL, "check we have an element");
454 delete last_handle_mark();
455 assert(last_handle_mark() == NULL, "check we have reached the end");
456
457 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
458 // We NULL out the fields for good hygiene.
459 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
460 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
461
462 delete handle_area();
463 delete metadata_handles();
464
465 // SR_handler uses this as a termination indicator -
466 // needs to happen before os::free_thread()
467 delete _SR_lock;
468 _SR_lock = NULL;
469
470 // osthread() can be NULL, if creation of thread failed.
471 if (osthread() != NULL) os::free_thread(osthread());
472
473 // Clear Thread::current if thread is deleting itself and it has not
474 // already been done. This must be done before the memory is deallocated.
475 // Needed to ensure JNI correctly detects non-attached threads.
476 if (this == Thread::current_or_null()) {
477 Thread::clear_thread_current();
478 }
479
480 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
481 }
482
483 #ifdef ASSERT
484 // A JavaThread is considered "dangling" if it is not the current
485 // thread, has been added the Threads list, the system is not at a
486 // safepoint and the Thread is not "protected".
487 //
488 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
489 assert(!thread->is_Java_thread() || Thread::current() == thread ||
490 !((JavaThread *) thread)->on_thread_list() ||
491 SafepointSynchronize::is_at_safepoint() ||
492 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
493 "possibility of dangling Thread pointer");
494 }
495 #endif
496
497 ThreadPriority Thread::get_priority(const Thread* const thread) {
498 ThreadPriority priority;
499 // Can return an error!
500 (void)os::get_priority(thread, priority);
501 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
502 return priority;
503 }
504
505 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
506 debug_only(check_for_dangling_thread_pointer(thread);)
507 // Can return an error!
508 (void)os::set_priority(thread, priority);
509 }
510
511
512 void Thread::start(Thread* thread) {
513 // Start is different from resume in that its safety is guaranteed by context or
514 // being called from a Java method synchronized on the Thread object.
515 if (!DisableStartThread) {
516 if (thread->is_Java_thread()) {
517 // Initialize the thread state to RUNNABLE before starting this thread.
518 // Can not set it after the thread started because we do not know the
519 // exact thread state at that time. It could be in MONITOR_WAIT or
520 // in SLEEPING or some other state.
521 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
522 java_lang_Thread::RUNNABLE);
523 }
524 os::start_thread(thread);
525 }
526 }
527
528 class InstallAsyncExceptionClosure : public HandshakeClosure {
529 Handle _throwable; // The Throwable thrown at the target Thread
530 public:
531 InstallAsyncExceptionClosure(Handle throwable) : HandshakeClosure("InstallAsyncException"), _throwable(throwable) {}
532
533 void do_thread(Thread* thr) {
534 JavaThread* target = (JavaThread*)thr;
535 // Note that this now allows multiple ThreadDeath exceptions to be
536 // thrown at a thread.
537 // The target thread has run and has not exited yet.
538 target->send_thread_stop(_throwable());
539 }
540 };
541
542 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
543 Handle throwable(Thread::current(), java_throwable);
544 JavaThread* target = java_lang_Thread::thread(java_thread);
545 InstallAsyncExceptionClosure vm_stop(throwable);
546 Handshake::execute(&vm_stop, target);
547 }
548
549
550 // Check if an external suspend request has completed (or has been
551 // cancelled). Returns true if the thread is externally suspended and
552 // false otherwise.
553 //
554 // The bits parameter returns information about the code path through
555 // the routine. Useful for debugging:
556 //
557 // set in is_ext_suspend_completed():
558 // 0x00000001 - routine was entered
559 // 0x00000010 - routine return false at end
560 // 0x00000100 - thread exited (return false)
561 // 0x00000200 - suspend request cancelled (return false)
562 // 0x00000400 - thread suspended (return true)
563 // 0x00001000 - thread is in a suspend equivalent state (return true)
564 // 0x00002000 - thread is native and walkable (return true)
565 // 0x00004000 - thread is native_trans and walkable (needed retry)
566 //
567 // set in wait_for_ext_suspend_completion():
568 // 0x00010000 - routine was entered
569 // 0x00020000 - suspend request cancelled before loop (return false)
570 // 0x00040000 - thread suspended before loop (return true)
571 // 0x00080000 - suspend request cancelled in loop (return false)
572 // 0x00100000 - thread suspended in loop (return true)
573 // 0x00200000 - suspend not completed during retry loop (return false)
574
575 // Helper class for tracing suspend wait debug bits.
576 //
577 // 0x00000100 indicates that the target thread exited before it could
578 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
579 // 0x00080000 each indicate a cancelled suspend request so they don't
580 // count as wait failures either.
581 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
582
583 class TraceSuspendDebugBits : public StackObj {
584 private:
585 JavaThread * jt;
586 bool is_wait;
587 bool called_by_wait; // meaningful when !is_wait
588 uint32_t * bits;
589
590 public:
591 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
592 uint32_t *_bits) {
593 jt = _jt;
594 is_wait = _is_wait;
595 called_by_wait = _called_by_wait;
596 bits = _bits;
597 }
598
599 ~TraceSuspendDebugBits() {
600 if (!is_wait) {
601 #if 1
602 // By default, don't trace bits for is_ext_suspend_completed() calls.
603 // That trace is very chatty.
604 return;
605 #else
606 if (!called_by_wait) {
607 // If tracing for is_ext_suspend_completed() is enabled, then only
608 // trace calls to it from wait_for_ext_suspend_completion()
609 return;
610 }
611 #endif
612 }
613
614 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
615 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
616 MutexLocker ml(Threads_lock); // needed for get_thread_name()
617 ResourceMark rm;
618
619 tty->print_cr(
620 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
621 jt->get_thread_name(), *bits);
622
623 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
624 }
625 }
626 }
627 };
628 #undef DEBUG_FALSE_BITS
629
630
631 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
632 uint32_t *bits) {
633 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
634
635 bool did_trans_retry = false; // only do thread_in_native_trans retry once
636 bool do_trans_retry; // flag to force the retry
637
638 *bits |= 0x00000001;
639
640 do {
641 do_trans_retry = false;
642
643 if (is_exiting()) {
644 // Thread is in the process of exiting. This is always checked
645 // first to reduce the risk of dereferencing a freed JavaThread.
646 *bits |= 0x00000100;
647 return false;
648 }
649
650 if (!is_external_suspend()) {
651 // Suspend request is cancelled. This is always checked before
652 // is_ext_suspended() to reduce the risk of a rogue resume
653 // confusing the thread that made the suspend request.
654 *bits |= 0x00000200;
655 return false;
656 }
657
658 if (is_ext_suspended()) {
659 // thread is suspended
660 *bits |= 0x00000400;
661 return true;
662 }
663
664 // Now that we no longer do hard suspends of threads running
665 // native code, the target thread can be changing thread state
666 // while we are in this routine:
667 //
668 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
669 //
670 // We save a copy of the thread state as observed at this moment
671 // and make our decision about suspend completeness based on the
672 // copy. This closes the race where the thread state is seen as
673 // _thread_in_native_trans in the if-thread_blocked check, but is
674 // seen as _thread_blocked in if-thread_in_native_trans check.
675 JavaThreadState save_state = thread_state();
676
677 if (save_state == _thread_blocked && is_suspend_equivalent()) {
678 // If the thread's state is _thread_blocked and this blocking
679 // condition is known to be equivalent to a suspend, then we can
680 // consider the thread to be externally suspended. This means that
681 // the code that sets _thread_blocked has been modified to do
682 // self-suspension if the blocking condition releases. We also
683 // used to check for CONDVAR_WAIT here, but that is now covered by
684 // the _thread_blocked with self-suspension check.
685 //
686 // Return true since we wouldn't be here unless there was still an
687 // external suspend request.
688 *bits |= 0x00001000;
689 return true;
690 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
691 // Threads running native code will self-suspend on native==>VM/Java
692 // transitions. If its stack is walkable (should always be the case
693 // unless this function is called before the actual java_suspend()
694 // call), then the wait is done.
695 *bits |= 0x00002000;
696 return true;
697 } else if (!called_by_wait && !did_trans_retry &&
698 save_state == _thread_in_native_trans &&
699 frame_anchor()->walkable()) {
700 // The thread is transitioning from thread_in_native to another
701 // thread state. check_safepoint_and_suspend_for_native_trans()
702 // will force the thread to self-suspend. If it hasn't gotten
703 // there yet we may have caught the thread in-between the native
704 // code check above and the self-suspend. Lucky us. If we were
705 // called by wait_for_ext_suspend_completion(), then it
706 // will be doing the retries so we don't have to.
707 //
708 // Since we use the saved thread state in the if-statement above,
709 // there is a chance that the thread has already transitioned to
710 // _thread_blocked by the time we get here. In that case, we will
711 // make a single unnecessary pass through the logic below. This
712 // doesn't hurt anything since we still do the trans retry.
713
714 *bits |= 0x00004000;
715
716 // Once the thread leaves thread_in_native_trans for another
717 // thread state, we break out of this retry loop. We shouldn't
718 // need this flag to prevent us from getting back here, but
719 // sometimes paranoia is good.
720 did_trans_retry = true;
721
722 // We wait for the thread to transition to a more usable state.
723 for (int i = 1; i <= SuspendRetryCount; i++) {
724 // We used to do an "os::yield_all(i)" call here with the intention
725 // that yielding would increase on each retry. However, the parameter
726 // is ignored on Linux which means the yield didn't scale up. Waiting
727 // on the SR_lock below provides a much more predictable scale up for
728 // the delay. It also provides a simple/direct point to check for any
729 // safepoint requests from the VMThread
730
731 // temporarily drops SR_lock while doing wait with safepoint check
732 // (if we're a JavaThread - the WatcherThread can also call this)
733 // and increase delay with each retry
734 if (Thread::current()->is_Java_thread()) {
735 SR_lock()->wait(i * delay);
736 } else {
737 SR_lock()->wait_without_safepoint_check(i * delay);
738 }
739
740 // check the actual thread state instead of what we saved above
741 if (thread_state() != _thread_in_native_trans) {
742 // the thread has transitioned to another thread state so
743 // try all the checks (except this one) one more time.
744 do_trans_retry = true;
745 break;
746 }
747 } // end retry loop
748
749
750 }
751 } while (do_trans_retry);
752
753 *bits |= 0x00000010;
754 return false;
755 }
756
757 // Wait for an external suspend request to complete (or be cancelled).
758 // Returns true if the thread is externally suspended and false otherwise.
759 //
760 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
761 uint32_t *bits) {
762 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
763 false /* !called_by_wait */, bits);
764
765 // local flag copies to minimize SR_lock hold time
766 bool is_suspended;
767 bool pending;
768 uint32_t reset_bits;
769
770 // set a marker so is_ext_suspend_completed() knows we are the caller
771 *bits |= 0x00010000;
772
773 // We use reset_bits to reinitialize the bits value at the top of
774 // each retry loop. This allows the caller to make use of any
775 // unused bits for their own marking purposes.
776 reset_bits = *bits;
777
778 {
779 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
780 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
781 delay, bits);
782 pending = is_external_suspend();
783 }
784 // must release SR_lock to allow suspension to complete
785
786 if (!pending) {
787 // A cancelled suspend request is the only false return from
788 // is_ext_suspend_completed() that keeps us from entering the
789 // retry loop.
790 *bits |= 0x00020000;
791 return false;
792 }
793
794 if (is_suspended) {
795 *bits |= 0x00040000;
796 return true;
797 }
798
799 for (int i = 1; i <= retries; i++) {
800 *bits = reset_bits; // reinit to only track last retry
801
802 // We used to do an "os::yield_all(i)" call here with the intention
803 // that yielding would increase on each retry. However, the parameter
804 // is ignored on Linux which means the yield didn't scale up. Waiting
805 // on the SR_lock below provides a much more predictable scale up for
806 // the delay. It also provides a simple/direct point to check for any
807 // safepoint requests from the VMThread
808
809 {
810 Thread* t = Thread::current();
811 MonitorLocker ml(SR_lock(),
812 t->is_Java_thread() ? Mutex::_safepoint_check_flag : Mutex::_no_safepoint_check_flag);
813 // wait with safepoint check (if we're a JavaThread - the WatcherThread
814 // can also call this) and increase delay with each retry
815 ml.wait(i * delay);
816
817 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
818 delay, bits);
819
820 // It is possible for the external suspend request to be cancelled
821 // (by a resume) before the actual suspend operation is completed.
822 // Refresh our local copy to see if we still need to wait.
823 pending = is_external_suspend();
824 }
825
826 if (!pending) {
827 // A cancelled suspend request is the only false return from
828 // is_ext_suspend_completed() that keeps us from staying in the
829 // retry loop.
830 *bits |= 0x00080000;
831 return false;
832 }
833
834 if (is_suspended) {
835 *bits |= 0x00100000;
836 return true;
837 }
838 } // end retry loop
839
840 // thread did not suspend after all our retries
841 *bits |= 0x00200000;
842 return false;
843 }
844
845 // Called from API entry points which perform stack walking. If the
846 // associated JavaThread is the current thread, then wait_for_suspend
847 // is not used. Otherwise, it determines if we should wait for the
848 // "other" thread to complete external suspension. (NOTE: in future
849 // releases the suspension mechanism should be reimplemented so this
850 // is not necessary.)
851 //
852 bool
853 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
854 if (this != JavaThread::current()) {
855 // "other" threads require special handling.
856 if (wait_for_suspend) {
857 // We are allowed to wait for the external suspend to complete
858 // so give the other thread a chance to get suspended.
859 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
860 SuspendRetryDelay, bits)) {
861 // Didn't make it so let the caller know.
862 return false;
863 }
864 }
865 // We aren't allowed to wait for the external suspend to complete
866 // so if the other thread isn't externally suspended we need to
867 // let the caller know.
868 else if (!is_ext_suspend_completed_with_lock(bits)) {
869 return false;
870 }
871 }
872
873 return true;
874 }
875
876 // GC Support
877 bool Thread::claim_par_threads_do(uintx claim_token) {
878 uintx token = _threads_do_token;
879 if (token != claim_token) {
880 uintx res = Atomic::cmpxchg(&_threads_do_token, token, claim_token);
881 if (res == token) {
882 return true;
883 }
884 guarantee(res == claim_token, "invariant");
885 }
886 return false;
887 }
888
889 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
890 active_handles()->oops_do(f);
891 // Do oop for ThreadShadow
892 f->do_oop((oop*)&_pending_exception);
893 handle_area()->oops_do(f);
894
895 // We scan thread local monitor lists here, and the remaining global
896 // monitors in ObjectSynchronizer::oops_do().
897 ObjectSynchronizer::thread_local_used_oops_do(this, f);
898 }
899
900 void Thread::metadata_handles_do(void f(Metadata*)) {
901 // Only walk the Handles in Thread.
902 if (metadata_handles() != NULL) {
903 for (int i = 0; i< metadata_handles()->length(); i++) {
904 f(metadata_handles()->at(i));
905 }
906 }
907 }
908
909 void Thread::print_on(outputStream* st, bool print_extended_info) const {
910 // get_priority assumes osthread initialized
911 if (osthread() != NULL) {
912 int os_prio;
913 if (os::get_native_priority(this, &os_prio) == OS_OK) {
914 st->print("os_prio=%d ", os_prio);
915 }
916
917 st->print("cpu=%.2fms ",
918 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
919 );
920 st->print("elapsed=%.2fs ",
921 _statistical_info.getElapsedTime() / 1000.0
922 );
923 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
924 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
925 st->print("allocated=" SIZE_FORMAT "%s ",
926 byte_size_in_proper_unit(allocated_bytes),
927 proper_unit_for_byte_size(allocated_bytes)
928 );
929 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
930 }
931
932 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
933 osthread()->print_on(st);
934 }
935 ThreadsSMRSupport::print_info_on(this, st);
936 st->print(" ");
937 debug_only(if (WizardMode) print_owned_locks_on(st);)
938 }
939
940 void Thread::print() const { print_on(tty); }
941
942 // Thread::print_on_error() is called by fatal error handler. Don't use
943 // any lock or allocate memory.
944 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
945 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
946
947 if (is_VM_thread()) { st->print("VMThread"); }
948 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
949 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
950 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
951 else { st->print("Thread"); }
952
953 if (is_Named_thread()) {
954 st->print(" \"%s\"", name());
955 }
956
957 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
958 p2i(stack_end()), p2i(stack_base()));
959
960 if (osthread()) {
961 st->print(" [id=%d]", osthread()->thread_id());
962 }
963
964 ThreadsSMRSupport::print_info_on(this, st);
965 }
966
967 void Thread::print_value_on(outputStream* st) const {
968 if (is_Named_thread()) {
969 st->print(" \"%s\" ", name());
970 }
971 st->print(INTPTR_FORMAT, p2i(this)); // print address
972 }
973
974 #ifdef ASSERT
975 void Thread::print_owned_locks_on(outputStream* st) const {
976 Mutex* cur = _owned_locks;
977 if (cur == NULL) {
978 st->print(" (no locks) ");
979 } else {
980 st->print_cr(" Locks owned:");
981 while (cur) {
982 cur->print_on(st);
983 cur = cur->next();
984 }
985 }
986 }
987
988 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
989 void Thread::check_possible_safepoint() {
990 if (!is_Java_thread()) return;
991
992 if (_no_safepoint_count > 0) {
993 print_owned_locks();
994 fatal("Possible safepoint reached by thread that does not allow it");
995 }
996 #ifdef CHECK_UNHANDLED_OOPS
997 // Clear unhandled oops in JavaThreads so we get a crash right away.
998 clear_unhandled_oops();
999 #endif // CHECK_UNHANDLED_OOPS
1000 }
1001
1002 void Thread::check_for_valid_safepoint_state() {
1003 if (!is_Java_thread()) return;
1004
1005 // Check NoSafepointVerifier, which is implied by locks taken that can be
1006 // shared with the VM thread. This makes sure that no locks with allow_vm_block
1007 // are held.
1008 check_possible_safepoint();
1009
1010 if (((JavaThread*)this)->thread_state() != _thread_in_vm) {
1011 fatal("LEAF method calling lock?");
1012 }
1013
1014 if (GCALotAtAllSafepoints) {
1015 // We could enter a safepoint here and thus have a gc
1016 InterfaceSupport::check_gc_alot();
1017 }
1018 }
1019 #endif // ASSERT
1020
1021 // Check for adr in the live portion of our stack.
1022 bool Thread::is_in_stack(address adr) const {
1023 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1024 address end = os::current_stack_pointer();
1025 return (stack_base() > adr && adr >= end);
1026 }
1027
1028 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1029 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1030 // used for compilation in the future. If that change is made, the need for these methods
1031 // should be revisited, and they should be removed if possible.
1032
1033 bool Thread::is_lock_owned(address adr) const {
1034 return on_local_stack(adr);
1035 }
1036
1037 bool Thread::set_as_starting_thread() {
1038 assert(_starting_thread == NULL, "already initialized: "
1039 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
1040 // NOTE: this must be called inside the main thread.
1041 DEBUG_ONLY(_starting_thread = this;)
1042 return os::create_main_thread((JavaThread*)this);
1043 }
1044
1045 static void initialize_class(Symbol* class_name, TRAPS) {
1046 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1047 InstanceKlass::cast(klass)->initialize(CHECK);
1048 }
1049
1050
1051 // Creates the initial ThreadGroup
1052 static Handle create_initial_thread_group(TRAPS) {
1053 Handle system_instance = JavaCalls::construct_new_instance(
1054 SystemDictionary::ThreadGroup_klass(),
1055 vmSymbols::void_method_signature(),
1056 CHECK_NH);
1057 Universe::set_system_thread_group(system_instance());
1058
1059 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1060 Handle main_instance = JavaCalls::construct_new_instance(
1061 SystemDictionary::ThreadGroup_klass(),
1062 vmSymbols::threadgroup_string_void_signature(),
1063 system_instance,
1064 string,
1065 CHECK_NH);
1066 return main_instance;
1067 }
1068
1069 // Creates the initial Thread
1070 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1071 TRAPS) {
1072 InstanceKlass* ik = SystemDictionary::Thread_klass();
1073 assert(ik->is_initialized(), "must be");
1074 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1075
1076 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1077 // constructor calls Thread.current(), which must be set here for the
1078 // initial thread.
1079 java_lang_Thread::set_thread(thread_oop(), thread);
1080 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1081 thread->set_threadObj(thread_oop());
1082
1083 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1084
1085 JavaValue result(T_VOID);
1086 JavaCalls::call_special(&result, thread_oop,
1087 ik,
1088 vmSymbols::object_initializer_name(),
1089 vmSymbols::threadgroup_string_void_signature(),
1090 thread_group,
1091 string,
1092 CHECK_NULL);
1093 return thread_oop();
1094 }
1095
1096 char java_runtime_name[128] = "";
1097 char java_runtime_version[128] = "";
1098 char java_runtime_vendor_version[128] = "";
1099 char java_runtime_vendor_vm_bug_url[128] = "";
1100
1101 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1102 static const char* get_java_runtime_name(TRAPS) {
1103 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1104 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1105 fieldDescriptor fd;
1106 bool found = k != NULL &&
1107 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1108 vmSymbols::string_signature(), &fd);
1109 if (found) {
1110 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1111 if (name_oop == NULL) {
1112 return NULL;
1113 }
1114 const char* name = java_lang_String::as_utf8_string(name_oop,
1115 java_runtime_name,
1116 sizeof(java_runtime_name));
1117 return name;
1118 } else {
1119 return NULL;
1120 }
1121 }
1122
1123 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1124 static const char* get_java_runtime_version(TRAPS) {
1125 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1126 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1127 fieldDescriptor fd;
1128 bool found = k != NULL &&
1129 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1130 vmSymbols::string_signature(), &fd);
1131 if (found) {
1132 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1133 if (name_oop == NULL) {
1134 return NULL;
1135 }
1136 const char* name = java_lang_String::as_utf8_string(name_oop,
1137 java_runtime_version,
1138 sizeof(java_runtime_version));
1139 return name;
1140 } else {
1141 return NULL;
1142 }
1143 }
1144
1145 // extract the JRE vendor version from java.lang.VersionProps.VENDOR_VERSION
1146 static const char* get_java_runtime_vendor_version(TRAPS) {
1147 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1148 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1149 fieldDescriptor fd;
1150 bool found = k != NULL &&
1151 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_vendor_version_name(),
1152 vmSymbols::string_signature(), &fd);
1153 if (found) {
1154 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1155 if (name_oop == NULL) {
1156 return NULL;
1157 }
1158 const char* name = java_lang_String::as_utf8_string(name_oop,
1159 java_runtime_vendor_version,
1160 sizeof(java_runtime_vendor_version));
1161 return name;
1162 } else {
1163 return NULL;
1164 }
1165 }
1166
1167 // extract the JRE vendor VM bug URL from java.lang.VersionProps.VENDOR_URL_VM_BUG
1168 static const char* get_java_runtime_vendor_vm_bug_url(TRAPS) {
1169 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1170 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1171 fieldDescriptor fd;
1172 bool found = k != NULL &&
1173 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_vendor_vm_bug_url_name(),
1174 vmSymbols::string_signature(), &fd);
1175 if (found) {
1176 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1177 if (name_oop == NULL) {
1178 return NULL;
1179 }
1180 const char* name = java_lang_String::as_utf8_string(name_oop,
1181 java_runtime_vendor_vm_bug_url,
1182 sizeof(java_runtime_vendor_vm_bug_url));
1183 return name;
1184 } else {
1185 return NULL;
1186 }
1187 }
1188
1189 // General purpose hook into Java code, run once when the VM is initialized.
1190 // The Java library method itself may be changed independently from the VM.
1191 static void call_postVMInitHook(TRAPS) {
1192 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1193 if (klass != NULL) {
1194 JavaValue result(T_VOID);
1195 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1196 vmSymbols::void_method_signature(),
1197 CHECK);
1198 }
1199 }
1200
1201 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1202 bool daemon, TRAPS) {
1203 assert(thread_group.not_null(), "thread group should be specified");
1204 assert(threadObj() == NULL, "should only create Java thread object once");
1205
1206 InstanceKlass* ik = SystemDictionary::Thread_klass();
1207 assert(ik->is_initialized(), "must be");
1208 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1209
1210 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1211 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1212 // constructor calls Thread.current(), which must be set here.
1213 java_lang_Thread::set_thread(thread_oop(), this);
1214 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1215 set_threadObj(thread_oop());
1216
1217 JavaValue result(T_VOID);
1218 if (thread_name != NULL) {
1219 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1220 // Thread gets assigned specified name and null target
1221 JavaCalls::call_special(&result,
1222 thread_oop,
1223 ik,
1224 vmSymbols::object_initializer_name(),
1225 vmSymbols::threadgroup_string_void_signature(),
1226 thread_group,
1227 name,
1228 THREAD);
1229 } else {
1230 // Thread gets assigned name "Thread-nnn" and null target
1231 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1232 JavaCalls::call_special(&result,
1233 thread_oop,
1234 ik,
1235 vmSymbols::object_initializer_name(),
1236 vmSymbols::threadgroup_runnable_void_signature(),
1237 thread_group,
1238 Handle(),
1239 THREAD);
1240 }
1241
1242
1243 if (daemon) {
1244 java_lang_Thread::set_daemon(thread_oop());
1245 }
1246
1247 if (HAS_PENDING_EXCEPTION) {
1248 return;
1249 }
1250
1251 Klass* group = SystemDictionary::ThreadGroup_klass();
1252 Handle threadObj(THREAD, this->threadObj());
1253
1254 JavaCalls::call_special(&result,
1255 thread_group,
1256 group,
1257 vmSymbols::add_method_name(),
1258 vmSymbols::thread_void_signature(),
1259 threadObj, // Arg 1
1260 THREAD);
1261 }
1262
1263 // List of all NonJavaThreads and safe iteration over that list.
1264
1265 class NonJavaThread::List {
1266 public:
1267 NonJavaThread* volatile _head;
1268 SingleWriterSynchronizer _protect;
1269
1270 List() : _head(NULL), _protect() {}
1271 };
1272
1273 NonJavaThread::List NonJavaThread::_the_list;
1274
1275 NonJavaThread::Iterator::Iterator() :
1276 _protect_enter(_the_list._protect.enter()),
1277 _current(Atomic::load_acquire(&_the_list._head))
1278 {}
1279
1280 NonJavaThread::Iterator::~Iterator() {
1281 _the_list._protect.exit(_protect_enter);
1282 }
1283
1284 void NonJavaThread::Iterator::step() {
1285 assert(!end(), "precondition");
1286 _current = Atomic::load_acquire(&_current->_next);
1287 }
1288
1289 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) {
1290 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!");
1291 }
1292
1293 NonJavaThread::~NonJavaThread() { }
1294
1295 void NonJavaThread::add_to_the_list() {
1296 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1297 // Initialize BarrierSet-related data before adding to list.
1298 BarrierSet::barrier_set()->on_thread_attach(this);
1299 Atomic::release_store(&_next, _the_list._head);
1300 Atomic::release_store(&_the_list._head, this);
1301 }
1302
1303 void NonJavaThread::remove_from_the_list() {
1304 {
1305 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1306 // Cleanup BarrierSet-related data before removing from list.
1307 BarrierSet::barrier_set()->on_thread_detach(this);
1308 NonJavaThread* volatile* p = &_the_list._head;
1309 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) {
1310 if (t == this) {
1311 *p = _next;
1312 break;
1313 }
1314 }
1315 }
1316 // Wait for any in-progress iterators. Concurrent synchronize is not
1317 // allowed, so do it while holding a dedicated lock. Outside and distinct
1318 // from NJTList_lock in case an iteration attempts to lock it.
1319 MutexLocker ml(NonJavaThreadsListSync_lock, Mutex::_no_safepoint_check_flag);
1320 _the_list._protect.synchronize();
1321 _next = NULL; // Safe to drop the link now.
1322 }
1323
1324 void NonJavaThread::pre_run() {
1325 add_to_the_list();
1326
1327 // This is slightly odd in that NamedThread is a subclass, but
1328 // in fact name() is defined in Thread
1329 assert(this->name() != NULL, "thread name was not set before it was started");
1330 this->set_native_thread_name(this->name());
1331 }
1332
1333 void NonJavaThread::post_run() {
1334 JFR_ONLY(Jfr::on_thread_exit(this);)
1335 remove_from_the_list();
1336 // Ensure thread-local-storage is cleared before termination.
1337 Thread::clear_thread_current();
1338 }
1339
1340 // NamedThread -- non-JavaThread subclasses with multiple
1341 // uniquely named instances should derive from this.
1342 NamedThread::NamedThread() :
1343 NonJavaThread(),
1344 _name(NULL),
1345 _processed_thread(NULL),
1346 _gc_id(GCId::undefined())
1347 {}
1348
1349 NamedThread::~NamedThread() {
1350 FREE_C_HEAP_ARRAY(char, _name);
1351 }
1352
1353 void NamedThread::set_name(const char* format, ...) {
1354 guarantee(_name == NULL, "Only get to set name once.");
1355 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1356 va_list ap;
1357 va_start(ap, format);
1358 jio_vsnprintf(_name, max_name_len, format, ap);
1359 va_end(ap);
1360 }
1361
1362 void NamedThread::print_on(outputStream* st) const {
1363 st->print("\"%s\" ", name());
1364 Thread::print_on(st);
1365 st->cr();
1366 }
1367
1368
1369 // ======= WatcherThread ========
1370
1371 // The watcher thread exists to simulate timer interrupts. It should
1372 // be replaced by an abstraction over whatever native support for
1373 // timer interrupts exists on the platform.
1374
1375 WatcherThread* WatcherThread::_watcher_thread = NULL;
1376 bool WatcherThread::_startable = false;
1377 volatile bool WatcherThread::_should_terminate = false;
1378
1379 WatcherThread::WatcherThread() : NonJavaThread() {
1380 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1381 if (os::create_thread(this, os::watcher_thread)) {
1382 _watcher_thread = this;
1383
1384 // Set the watcher thread to the highest OS priority which should not be
1385 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1386 // is created. The only normal thread using this priority is the reference
1387 // handler thread, which runs for very short intervals only.
1388 // If the VMThread's priority is not lower than the WatcherThread profiling
1389 // will be inaccurate.
1390 os::set_priority(this, MaxPriority);
1391 if (!DisableStartThread) {
1392 os::start_thread(this);
1393 }
1394 }
1395 }
1396
1397 int WatcherThread::sleep() const {
1398 // The WatcherThread does not participate in the safepoint protocol
1399 // for the PeriodicTask_lock because it is not a JavaThread.
1400 MonitorLocker ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1401
1402 if (_should_terminate) {
1403 // check for termination before we do any housekeeping or wait
1404 return 0; // we did not sleep.
1405 }
1406
1407 // remaining will be zero if there are no tasks,
1408 // causing the WatcherThread to sleep until a task is
1409 // enrolled
1410 int remaining = PeriodicTask::time_to_wait();
1411 int time_slept = 0;
1412
1413 // we expect this to timeout - we only ever get unparked when
1414 // we should terminate or when a new task has been enrolled
1415 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1416
1417 jlong time_before_loop = os::javaTimeNanos();
1418
1419 while (true) {
1420 bool timedout = ml.wait(remaining);
1421 jlong now = os::javaTimeNanos();
1422
1423 if (remaining == 0) {
1424 // if we didn't have any tasks we could have waited for a long time
1425 // consider the time_slept zero and reset time_before_loop
1426 time_slept = 0;
1427 time_before_loop = now;
1428 } else {
1429 // need to recalculate since we might have new tasks in _tasks
1430 time_slept = (int) ((now - time_before_loop) / 1000000);
1431 }
1432
1433 // Change to task list or spurious wakeup of some kind
1434 if (timedout || _should_terminate) {
1435 break;
1436 }
1437
1438 remaining = PeriodicTask::time_to_wait();
1439 if (remaining == 0) {
1440 // Last task was just disenrolled so loop around and wait until
1441 // another task gets enrolled
1442 continue;
1443 }
1444
1445 remaining -= time_slept;
1446 if (remaining <= 0) {
1447 break;
1448 }
1449 }
1450
1451 return time_slept;
1452 }
1453
1454 void WatcherThread::run() {
1455 assert(this == watcher_thread(), "just checking");
1456
1457 this->set_active_handles(JNIHandleBlock::allocate_block());
1458 while (true) {
1459 assert(watcher_thread() == Thread::current(), "thread consistency check");
1460 assert(watcher_thread() == this, "thread consistency check");
1461
1462 // Calculate how long it'll be until the next PeriodicTask work
1463 // should be done, and sleep that amount of time.
1464 int time_waited = sleep();
1465
1466 if (VMError::is_error_reported()) {
1467 // A fatal error has happened, the error handler(VMError::report_and_die)
1468 // should abort JVM after creating an error log file. However in some
1469 // rare cases, the error handler itself might deadlock. Here periodically
1470 // check for error reporting timeouts, and if it happens, just proceed to
1471 // abort the VM.
1472
1473 // This code is in WatcherThread because WatcherThread wakes up
1474 // periodically so the fatal error handler doesn't need to do anything;
1475 // also because the WatcherThread is less likely to crash than other
1476 // threads.
1477
1478 for (;;) {
1479 // Note: we use naked sleep in this loop because we want to avoid using
1480 // any kind of VM infrastructure which may be broken at this point.
1481 if (VMError::check_timeout()) {
1482 // We hit error reporting timeout. Error reporting was interrupted and
1483 // will be wrapping things up now (closing files etc). Give it some more
1484 // time, then quit the VM.
1485 os::naked_short_sleep(200);
1486 // Print a message to stderr.
1487 fdStream err(defaultStream::output_fd());
1488 err.print_raw_cr("# [ timer expired, abort... ]");
1489 // skip atexit/vm_exit/vm_abort hooks
1490 os::die();
1491 }
1492
1493 // Wait a second, then recheck for timeout.
1494 os::naked_short_sleep(999);
1495 }
1496 }
1497
1498 if (_should_terminate) {
1499 // check for termination before posting the next tick
1500 break;
1501 }
1502
1503 PeriodicTask::real_time_tick(time_waited);
1504 }
1505
1506 // Signal that it is terminated
1507 {
1508 MutexLocker mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1509 _watcher_thread = NULL;
1510 Terminator_lock->notify_all();
1511 }
1512 }
1513
1514 void WatcherThread::start() {
1515 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1516
1517 if (watcher_thread() == NULL && _startable) {
1518 _should_terminate = false;
1519 // Create the single instance of WatcherThread
1520 new WatcherThread();
1521 }
1522 }
1523
1524 void WatcherThread::make_startable() {
1525 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1526 _startable = true;
1527 }
1528
1529 void WatcherThread::stop() {
1530 {
1531 // Follow normal safepoint aware lock enter protocol since the
1532 // WatcherThread is stopped by another JavaThread.
1533 MutexLocker ml(PeriodicTask_lock);
1534 _should_terminate = true;
1535
1536 WatcherThread* watcher = watcher_thread();
1537 if (watcher != NULL) {
1538 // unpark the WatcherThread so it can see that it should terminate
1539 watcher->unpark();
1540 }
1541 }
1542
1543 MonitorLocker mu(Terminator_lock);
1544
1545 while (watcher_thread() != NULL) {
1546 // This wait should make safepoint checks, wait without a timeout,
1547 // and wait as a suspend-equivalent condition.
1548 mu.wait(0, Mutex::_as_suspend_equivalent_flag);
1549 }
1550 }
1551
1552 void WatcherThread::unpark() {
1553 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1554 PeriodicTask_lock->notify();
1555 }
1556
1557 void WatcherThread::print_on(outputStream* st) const {
1558 st->print("\"%s\" ", name());
1559 Thread::print_on(st);
1560 st->cr();
1561 }
1562
1563 // ======= JavaThread ========
1564
1565 #if INCLUDE_JVMCI
1566
1567 jlong* JavaThread::_jvmci_old_thread_counters;
1568
1569 bool jvmci_counters_include(JavaThread* thread) {
1570 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1571 }
1572
1573 void JavaThread::collect_counters(jlong* array, int length) {
1574 assert(length == JVMCICounterSize, "wrong value");
1575 for (int i = 0; i < length; i++) {
1576 array[i] = _jvmci_old_thread_counters[i];
1577 }
1578 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
1579 if (jvmci_counters_include(tp)) {
1580 for (int i = 0; i < length; i++) {
1581 array[i] += tp->_jvmci_counters[i];
1582 }
1583 }
1584 }
1585 }
1586
1587 // Attempt to enlarge the array for per thread counters.
1588 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
1589 jlong* new_counters = NEW_C_HEAP_ARRAY(jlong, new_size, mtJVMCI);
1590 if (old_counters == NULL) {
1591 old_counters = new_counters;
1592 memset(old_counters, 0, sizeof(jlong) * new_size);
1593 } else {
1594 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
1595 new_counters[i] = old_counters[i];
1596 }
1597 if (new_size > current_size) {
1598 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
1599 }
1600 FREE_C_HEAP_ARRAY(jlong, old_counters);
1601 }
1602 return new_counters;
1603 }
1604
1605 // Attempt to enlarge the array for per thread counters.
1606 void JavaThread::resize_counters(int current_size, int new_size) {
1607 _jvmci_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
1608 }
1609
1610 class VM_JVMCIResizeCounters : public VM_Operation {
1611 private:
1612 int _new_size;
1613
1614 public:
1615 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size) { }
1616 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
1617 bool allow_nested_vm_operations() const { return true; }
1618 void doit() {
1619 // Resize the old thread counters array
1620 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
1621 JavaThread::_jvmci_old_thread_counters = new_counters;
1622
1623 // Now resize each threads array
1624 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
1625 tp->resize_counters(JVMCICounterSize, _new_size);
1626 }
1627 JVMCICounterSize = _new_size;
1628 }
1629 };
1630
1631 void JavaThread::resize_all_jvmci_counters(int new_size) {
1632 VM_JVMCIResizeCounters op(new_size);
1633 VMThread::execute(&op);
1634 }
1635
1636 #endif // INCLUDE_JVMCI
1637
1638 // A JavaThread is a normal Java thread
1639
1640 void JavaThread::initialize() {
1641 // Initialize fields
1642
1643 set_saved_exception_pc(NULL);
1644 set_threadObj(NULL);
1645 _anchor.clear();
1646 set_entry_point(NULL);
1647 set_jni_functions(jni_functions());
1648 set_callee_target(NULL);
1649 set_vm_result(NULL);
1650 set_vm_result_2(NULL);
1651 set_vframe_array_head(NULL);
1652 set_vframe_array_last(NULL);
1653 set_deferred_locals(NULL);
1654 set_deopt_mark(NULL);
1655 set_deopt_compiled_method(NULL);
1656 set_monitor_chunks(NULL);
1657 _on_thread_list = false;
1658 _thread_state = _thread_new;
1659 _terminated = _not_terminated;
1660 _array_for_gc = NULL;
1661 _suspend_equivalent = false;
1662 _in_deopt_handler = 0;
1663 _doing_unsafe_access = false;
1664 _stack_guard_state = stack_guard_unused;
1665 #if INCLUDE_JVMCI
1666 _pending_monitorenter = false;
1667 _pending_deoptimization = -1;
1668 _pending_failed_speculation = 0;
1669 _pending_transfer_to_interpreter = false;
1670 _in_retryable_allocation = false;
1671 _jvmci._alternate_call_target = NULL;
1672 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1673 _jvmci_counters = NULL;
1674 if (JVMCICounterSize > 0) {
1675 resize_counters(0, (int) JVMCICounterSize);
1676 }
1677 #endif // INCLUDE_JVMCI
1678 _reserved_stack_activation = NULL; // stack base not known yet
1679 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1680 _exception_pc = 0;
1681 _exception_handler_pc = 0;
1682 _is_method_handle_return = 0;
1683 _jvmti_thread_state= NULL;
1684 _should_post_on_exceptions_flag = JNI_FALSE;
1685 _interp_only_mode = 0;
1686 _special_runtime_exit_condition = _no_async_condition;
1687 _pending_async_exception = NULL;
1688 _thread_stat = NULL;
1689 _thread_stat = new ThreadStatistics();
1690 _jni_active_critical = 0;
1691 _pending_jni_exception_check_fn = NULL;
1692 _do_not_unlock_if_synchronized = false;
1693 _cached_monitor_info = NULL;
1694 _parker = Parker::Allocate(this);
1695 _SleepEvent = ParkEvent::Allocate(this);
1696 // Setup safepoint state info for this thread
1697 ThreadSafepointState::create(this);
1698
1699 debug_only(_java_call_counter = 0);
1700
1701 // JVMTI PopFrame support
1702 _popframe_condition = popframe_inactive;
1703 _popframe_preserved_args = NULL;
1704 _popframe_preserved_args_size = 0;
1705 _frames_to_pop_failed_realloc = 0;
1706
1707 if (SafepointMechanism::uses_thread_local_poll()) {
1708 SafepointMechanism::initialize_header(this);
1709 }
1710
1711 _class_to_be_initialized = NULL;
1712
1713 pd_initialize();
1714 }
1715
1716 JavaThread::JavaThread(bool is_attaching_via_jni) :
1717 Thread() {
1718 initialize();
1719 if (is_attaching_via_jni) {
1720 _jni_attach_state = _attaching_via_jni;
1721 } else {
1722 _jni_attach_state = _not_attaching_via_jni;
1723 }
1724 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1725 }
1726
1727
1728 // interrupt support
1729
1730 void JavaThread::interrupt() {
1731 debug_only(check_for_dangling_thread_pointer(this);)
1732
1733 // For Windows _interrupt_event
1734 osthread()->set_interrupted(true);
1735
1736 // For Thread.sleep
1737 _SleepEvent->unpark();
1738
1739 // For JSR166 LockSupport.park
1740 parker()->unpark();
1741
1742 // For ObjectMonitor and JvmtiRawMonitor
1743 _ParkEvent->unpark();
1744 }
1745
1746
1747 bool JavaThread::is_interrupted(bool clear_interrupted) {
1748 debug_only(check_for_dangling_thread_pointer(this);)
1749
1750 if (threadObj() == NULL) {
1751 // If there is no j.l.Thread then it is impossible to have
1752 // been interrupted. We can find NULL during VM initialization
1753 // or when a JNI thread is still in the process of attaching.
1754 // In such cases this must be the current thread.
1755 assert(this == Thread::current(), "invariant");
1756 return false;
1757 }
1758
1759 bool interrupted = java_lang_Thread::interrupted(threadObj());
1760
1761 // NOTE that since there is no "lock" around the interrupt and
1762 // is_interrupted operations, there is the possibility that the
1763 // interrupted flag will be "false" but that the
1764 // low-level events will be in the signaled state. This is
1765 // intentional. The effect of this is that Object.wait() and
1766 // LockSupport.park() will appear to have a spurious wakeup, which
1767 // is allowed and not harmful, and the possibility is so rare that
1768 // it is not worth the added complexity to add yet another lock.
1769 // For the sleep event an explicit reset is performed on entry
1770 // to JavaThread::sleep, so there is no early return. It has also been
1771 // recommended not to put the interrupted flag into the "event"
1772 // structure because it hides the issue.
1773 // Also, because there is no lock, we must only clear the interrupt
1774 // state if we are going to report that we were interrupted; otherwise
1775 // an interrupt that happens just after we read the field would be lost.
1776 if (interrupted && clear_interrupted) {
1777 assert(this == Thread::current(), "only the current thread can clear");
1778 java_lang_Thread::set_interrupted(threadObj(), false);
1779 osthread()->set_interrupted(false);
1780 }
1781
1782 return interrupted;
1783 }
1784
1785 bool JavaThread::reguard_stack(address cur_sp) {
1786 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1787 && _stack_guard_state != stack_guard_reserved_disabled) {
1788 return true; // Stack already guarded or guard pages not needed.
1789 }
1790
1791 if (register_stack_overflow()) {
1792 // For those architectures which have separate register and
1793 // memory stacks, we must check the register stack to see if
1794 // it has overflowed.
1795 return false;
1796 }
1797
1798 // Java code never executes within the yellow zone: the latter is only
1799 // there to provoke an exception during stack banging. If java code
1800 // is executing there, either StackShadowPages should be larger, or
1801 // some exception code in c1, c2 or the interpreter isn't unwinding
1802 // when it should.
1803 guarantee(cur_sp > stack_reserved_zone_base(),
1804 "not enough space to reguard - increase StackShadowPages");
1805 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1806 enable_stack_yellow_reserved_zone();
1807 if (reserved_stack_activation() != stack_base()) {
1808 set_reserved_stack_activation(stack_base());
1809 }
1810 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1811 set_reserved_stack_activation(stack_base());
1812 enable_stack_reserved_zone();
1813 }
1814 return true;
1815 }
1816
1817 bool JavaThread::reguard_stack(void) {
1818 return reguard_stack(os::current_stack_pointer());
1819 }
1820
1821
1822 // Check for adr in the usable portion of this thread's stack.
1823 bool JavaThread::is_in_usable_stack(address adr) const {
1824 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1825 size_t usable_stack_size = _stack_size - stack_guard_size;
1826
1827 return ((stack_base() > adr) && (adr >= (stack_base() - usable_stack_size)));
1828 }
1829
1830 void JavaThread::block_if_vm_exited() {
1831 if (_terminated == _vm_exited) {
1832 // _vm_exited is set at safepoint, and Threads_lock is never released
1833 // we will block here forever.
1834 // Here we can be doing a jump from a safe state to an unsafe state without
1835 // proper transition, but it happens after the final safepoint has begun.
1836 set_thread_state(_thread_in_vm);
1837 Threads_lock->lock();
1838 ShouldNotReachHere();
1839 }
1840 }
1841
1842
1843 // Remove this ifdef when C1 is ported to the compiler interface.
1844 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1845 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1846
1847 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1848 Thread() {
1849 initialize();
1850 _jni_attach_state = _not_attaching_via_jni;
1851 set_entry_point(entry_point);
1852 // Create the native thread itself.
1853 // %note runtime_23
1854 os::ThreadType thr_type = os::java_thread;
1855 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1856 os::java_thread;
1857 os::create_thread(this, thr_type, stack_sz);
1858 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1859 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1860 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1861 // the exception consists of creating the exception object & initializing it, initialization
1862 // will leave the VM via a JavaCall and then all locks must be unlocked).
1863 //
1864 // The thread is still suspended when we reach here. Thread must be explicit started
1865 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1866 // by calling Threads:add. The reason why this is not done here, is because the thread
1867 // object must be fully initialized (take a look at JVM_Start)
1868 }
1869
1870 JavaThread::~JavaThread() {
1871
1872 // JSR166 -- return the parker to the free list
1873 Parker::Release(_parker);
1874 _parker = NULL;
1875
1876 // Return the sleep event to the free list
1877 ParkEvent::Release(_SleepEvent);
1878 _SleepEvent = NULL;
1879
1880 // Free any remaining previous UnrollBlock
1881 vframeArray* old_array = vframe_array_last();
1882
1883 if (old_array != NULL) {
1884 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1885 old_array->set_unroll_block(NULL);
1886 delete old_info;
1887 delete old_array;
1888 }
1889
1890 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1891 if (deferred != NULL) {
1892 // This can only happen if thread is destroyed before deoptimization occurs.
1893 assert(deferred->length() != 0, "empty array!");
1894 do {
1895 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1896 deferred->remove_at(0);
1897 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1898 delete dlv;
1899 } while (deferred->length() != 0);
1900 delete deferred;
1901 }
1902
1903 // All Java related clean up happens in exit
1904 ThreadSafepointState::destroy(this);
1905 if (_thread_stat != NULL) delete _thread_stat;
1906
1907 #if INCLUDE_JVMCI
1908 if (JVMCICounterSize > 0) {
1909 if (jvmci_counters_include(this)) {
1910 for (int i = 0; i < JVMCICounterSize; i++) {
1911 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1912 }
1913 }
1914 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1915 }
1916 #endif // INCLUDE_JVMCI
1917 }
1918
1919
1920 // First JavaThread specific code executed by a new Java thread.
1921 void JavaThread::pre_run() {
1922 // empty - see comments in run()
1923 }
1924
1925 // The main routine called by a new Java thread. This isn't overridden
1926 // by subclasses, instead different subclasses define a different "entry_point"
1927 // which defines the actual logic for that kind of thread.
1928 void JavaThread::run() {
1929 // initialize thread-local alloc buffer related fields
1930 this->initialize_tlab();
1931
1932 // Used to test validity of stack trace backs.
1933 // This can't be moved into pre_run() else we invalidate
1934 // the requirement that thread_main_inner is lower on
1935 // the stack. Consequently all the initialization logic
1936 // stays here in run() rather than pre_run().
1937 this->record_base_of_stack_pointer();
1938
1939 this->create_stack_guard_pages();
1940
1941 this->cache_global_variables();
1942
1943 // Thread is now sufficiently initialized to be handled by the safepoint code as being
1944 // in the VM. Change thread state from _thread_new to _thread_in_vm
1945 ThreadStateTransition::transition(this, _thread_new, _thread_in_vm);
1946 // Before a thread is on the threads list it is always safe, so after leaving the
1947 // _thread_new we should emit a instruction barrier. The distance to modified code
1948 // from here is probably far enough, but this is consistent and safe.
1949 OrderAccess::cross_modify_fence();
1950
1951 assert(JavaThread::current() == this, "sanity check");
1952 assert(!Thread::current()->owns_locks(), "sanity check");
1953
1954 DTRACE_THREAD_PROBE(start, this);
1955
1956 // This operation might block. We call that after all safepoint checks for a new thread has
1957 // been completed.
1958 this->set_active_handles(JNIHandleBlock::allocate_block());
1959
1960 if (JvmtiExport::should_post_thread_life()) {
1961 JvmtiExport::post_thread_start(this);
1962
1963 }
1964
1965 // We call another function to do the rest so we are sure that the stack addresses used
1966 // from there will be lower than the stack base just computed.
1967 thread_main_inner();
1968 }
1969
1970 void JavaThread::thread_main_inner() {
1971 assert(JavaThread::current() == this, "sanity check");
1972 assert(this->threadObj() != NULL, "just checking");
1973
1974 // Execute thread entry point unless this thread has a pending exception
1975 // or has been stopped before starting.
1976 // Note: Due to JVM_StopThread we can have pending exceptions already!
1977 if (!this->has_pending_exception() &&
1978 !java_lang_Thread::is_stillborn(this->threadObj())) {
1979 {
1980 ResourceMark rm(this);
1981 this->set_native_thread_name(this->get_thread_name());
1982 }
1983 HandleMark hm(this);
1984 this->entry_point()(this, this);
1985 }
1986
1987 DTRACE_THREAD_PROBE(stop, this);
1988
1989 // Cleanup is handled in post_run()
1990 }
1991
1992 // Shared teardown for all JavaThreads
1993 void JavaThread::post_run() {
1994 this->exit(false);
1995 // Defer deletion to here to ensure 'this' is still referenceable in call_run
1996 // for any shared tear-down.
1997 this->smr_delete();
1998 }
1999
2000 static void ensure_join(JavaThread* thread) {
2001 // We do not need to grab the Threads_lock, since we are operating on ourself.
2002 Handle threadObj(thread, thread->threadObj());
2003 assert(threadObj.not_null(), "java thread object must exist");
2004 ObjectLocker lock(threadObj, thread);
2005 // Ignore pending exception (ThreadDeath), since we are exiting anyway
2006 thread->clear_pending_exception();
2007 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
2008 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
2009 // Clear the native thread instance - this makes isAlive return false and allows the join()
2010 // to complete once we've done the notify_all below
2011 java_lang_Thread::set_thread(threadObj(), NULL);
2012 lock.notify_all(thread);
2013 // Ignore pending exception (ThreadDeath), since we are exiting anyway
2014 thread->clear_pending_exception();
2015 }
2016
2017 static bool is_daemon(oop threadObj) {
2018 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
2019 }
2020
2021 // For any new cleanup additions, please check to see if they need to be applied to
2022 // cleanup_failed_attach_current_thread as well.
2023 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
2024 assert(this == JavaThread::current(), "thread consistency check");
2025
2026 elapsedTimer _timer_exit_phase1;
2027 elapsedTimer _timer_exit_phase2;
2028 elapsedTimer _timer_exit_phase3;
2029 elapsedTimer _timer_exit_phase4;
2030
2031 if (log_is_enabled(Debug, os, thread, timer)) {
2032 _timer_exit_phase1.start();
2033 }
2034
2035 HandleMark hm(this);
2036 Handle uncaught_exception(this, this->pending_exception());
2037 this->clear_pending_exception();
2038 Handle threadObj(this, this->threadObj());
2039 assert(threadObj.not_null(), "Java thread object should be created");
2040
2041 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
2042 {
2043 EXCEPTION_MARK;
2044
2045 CLEAR_PENDING_EXCEPTION;
2046 }
2047 if (!destroy_vm) {
2048 if (uncaught_exception.not_null()) {
2049 EXCEPTION_MARK;
2050 // Call method Thread.dispatchUncaughtException().
2051 Klass* thread_klass = SystemDictionary::Thread_klass();
2052 JavaValue result(T_VOID);
2053 JavaCalls::call_virtual(&result,
2054 threadObj, thread_klass,
2055 vmSymbols::dispatchUncaughtException_name(),
2056 vmSymbols::throwable_void_signature(),
2057 uncaught_exception,
2058 THREAD);
2059 if (HAS_PENDING_EXCEPTION) {
2060 ResourceMark rm(this);
2061 jio_fprintf(defaultStream::error_stream(),
2062 "\nException: %s thrown from the UncaughtExceptionHandler"
2063 " in thread \"%s\"\n",
2064 pending_exception()->klass()->external_name(),
2065 get_thread_name());
2066 CLEAR_PENDING_EXCEPTION;
2067 }
2068 }
2069 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
2070
2071 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
2072 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
2073 // is deprecated anyhow.
2074 if (!is_Compiler_thread()) {
2075 int count = 3;
2076 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
2077 EXCEPTION_MARK;
2078 JavaValue result(T_VOID);
2079 Klass* thread_klass = SystemDictionary::Thread_klass();
2080 JavaCalls::call_virtual(&result,
2081 threadObj, thread_klass,
2082 vmSymbols::exit_method_name(),
2083 vmSymbols::void_method_signature(),
2084 THREAD);
2085 CLEAR_PENDING_EXCEPTION;
2086 }
2087 }
2088 // notify JVMTI
2089 if (JvmtiExport::should_post_thread_life()) {
2090 JvmtiExport::post_thread_end(this);
2091 }
2092
2093 // We have notified the agents that we are exiting, before we go on,
2094 // we must check for a pending external suspend request and honor it
2095 // in order to not surprise the thread that made the suspend request.
2096 while (true) {
2097 {
2098 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2099 if (!is_external_suspend()) {
2100 set_terminated(_thread_exiting);
2101 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
2102 break;
2103 }
2104 // Implied else:
2105 // Things get a little tricky here. We have a pending external
2106 // suspend request, but we are holding the SR_lock so we
2107 // can't just self-suspend. So we temporarily drop the lock
2108 // and then self-suspend.
2109 }
2110
2111 ThreadBlockInVM tbivm(this);
2112 java_suspend_self();
2113
2114 // We're done with this suspend request, but we have to loop around
2115 // and check again. Eventually we will get SR_lock without a pending
2116 // external suspend request and will be able to mark ourselves as
2117 // exiting.
2118 }
2119 // no more external suspends are allowed at this point
2120 } else {
2121 assert(!is_terminated() && !is_exiting(), "must not be exiting");
2122 // before_exit() has already posted JVMTI THREAD_END events
2123 }
2124
2125 if (log_is_enabled(Debug, os, thread, timer)) {
2126 _timer_exit_phase1.stop();
2127 _timer_exit_phase2.start();
2128 }
2129
2130 // Capture daemon status before the thread is marked as terminated.
2131 bool daemon = is_daemon(threadObj());
2132
2133 // Notify waiters on thread object. This has to be done after exit() is called
2134 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
2135 // group should have the destroyed bit set before waiters are notified).
2136 ensure_join(this);
2137 assert(!this->has_pending_exception(), "ensure_join should have cleared");
2138
2139 if (log_is_enabled(Debug, os, thread, timer)) {
2140 _timer_exit_phase2.stop();
2141 _timer_exit_phase3.start();
2142 }
2143 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
2144 // held by this thread must be released. The spec does not distinguish
2145 // between JNI-acquired and regular Java monitors. We can only see
2146 // regular Java monitors here if monitor enter-exit matching is broken.
2147 //
2148 // ensure_join() ignores IllegalThreadStateExceptions, and so does
2149 // ObjectSynchronizer::release_monitors_owned_by_thread().
2150 if (exit_type == jni_detach) {
2151 // Sanity check even though JNI DetachCurrentThread() would have
2152 // returned JNI_ERR if there was a Java frame. JavaThread exit
2153 // should be done executing Java code by the time we get here.
2154 assert(!this->has_last_Java_frame(),
2155 "should not have a Java frame when detaching or exiting");
2156 ObjectSynchronizer::release_monitors_owned_by_thread(this);
2157 assert(!this->has_pending_exception(), "release_monitors should have cleared");
2158 }
2159
2160 // These things needs to be done while we are still a Java Thread. Make sure that thread
2161 // is in a consistent state, in case GC happens
2162 JFR_ONLY(Jfr::on_thread_exit(this);)
2163
2164 if (active_handles() != NULL) {
2165 JNIHandleBlock* block = active_handles();
2166 set_active_handles(NULL);
2167 JNIHandleBlock::release_block(block);
2168 }
2169
2170 if (free_handle_block() != NULL) {
2171 JNIHandleBlock* block = free_handle_block();
2172 set_free_handle_block(NULL);
2173 JNIHandleBlock::release_block(block);
2174 }
2175
2176 // These have to be removed while this is still a valid thread.
2177 remove_stack_guard_pages();
2178
2179 if (UseTLAB) {
2180 tlab().retire();
2181 }
2182
2183 if (JvmtiEnv::environments_might_exist()) {
2184 JvmtiExport::cleanup_thread(this);
2185 }
2186
2187 // We must flush any deferred card marks and other various GC barrier
2188 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2189 // before removing a thread from the list of active threads.
2190 BarrierSet::barrier_set()->on_thread_detach(this);
2191
2192 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2193 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2194 os::current_thread_id());
2195
2196 if (log_is_enabled(Debug, os, thread, timer)) {
2197 _timer_exit_phase3.stop();
2198 _timer_exit_phase4.start();
2199 }
2200 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2201 Threads::remove(this, daemon);
2202
2203 if (log_is_enabled(Debug, os, thread, timer)) {
2204 _timer_exit_phase4.stop();
2205 ResourceMark rm(this);
2206 log_debug(os, thread, timer)("name='%s'"
2207 ", exit-phase1=" JLONG_FORMAT
2208 ", exit-phase2=" JLONG_FORMAT
2209 ", exit-phase3=" JLONG_FORMAT
2210 ", exit-phase4=" JLONG_FORMAT,
2211 get_thread_name(),
2212 _timer_exit_phase1.milliseconds(),
2213 _timer_exit_phase2.milliseconds(),
2214 _timer_exit_phase3.milliseconds(),
2215 _timer_exit_phase4.milliseconds());
2216 }
2217 }
2218
2219 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
2220 if (active_handles() != NULL) {
2221 JNIHandleBlock* block = active_handles();
2222 set_active_handles(NULL);
2223 JNIHandleBlock::release_block(block);
2224 }
2225
2226 if (free_handle_block() != NULL) {
2227 JNIHandleBlock* block = free_handle_block();
2228 set_free_handle_block(NULL);
2229 JNIHandleBlock::release_block(block);
2230 }
2231
2232 // These have to be removed while this is still a valid thread.
2233 remove_stack_guard_pages();
2234
2235 if (UseTLAB) {
2236 tlab().retire();
2237 }
2238
2239 BarrierSet::barrier_set()->on_thread_detach(this);
2240
2241 Threads::remove(this, is_daemon);
2242 this->smr_delete();
2243 }
2244
2245 JavaThread* JavaThread::active() {
2246 Thread* thread = Thread::current();
2247 if (thread->is_Java_thread()) {
2248 return (JavaThread*) thread;
2249 } else {
2250 assert(thread->is_VM_thread(), "this must be a vm thread");
2251 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2252 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2253 assert(ret->is_Java_thread(), "must be a Java thread");
2254 return ret;
2255 }
2256 }
2257
2258 bool JavaThread::is_lock_owned(address adr) const {
2259 if (Thread::is_lock_owned(adr)) return true;
2260
2261 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2262 if (chunk->contains(adr)) return true;
2263 }
2264
2265 return false;
2266 }
2267
2268
2269 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2270 chunk->set_next(monitor_chunks());
2271 set_monitor_chunks(chunk);
2272 }
2273
2274 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2275 guarantee(monitor_chunks() != NULL, "must be non empty");
2276 if (monitor_chunks() == chunk) {
2277 set_monitor_chunks(chunk->next());
2278 } else {
2279 MonitorChunk* prev = monitor_chunks();
2280 while (prev->next() != chunk) prev = prev->next();
2281 prev->set_next(chunk->next());
2282 }
2283 }
2284
2285 // JVM support.
2286
2287 // Note: this function shouldn't block if it's called in
2288 // _thread_in_native_trans state (such as from
2289 // check_special_condition_for_native_trans()).
2290 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2291
2292 if (has_last_Java_frame() && has_async_condition()) {
2293 // If we are at a polling page safepoint (not a poll return)
2294 // then we must defer async exception because live registers
2295 // will be clobbered by the exception path. Poll return is
2296 // ok because the call we a returning from already collides
2297 // with exception handling registers and so there is no issue.
2298 // (The exception handling path kills call result registers but
2299 // this is ok since the exception kills the result anyway).
2300
2301 if (is_at_poll_safepoint()) {
2302 // if the code we are returning to has deoptimized we must defer
2303 // the exception otherwise live registers get clobbered on the
2304 // exception path before deoptimization is able to retrieve them.
2305 //
2306 RegisterMap map(this, false);
2307 frame caller_fr = last_frame().sender(&map);
2308 assert(caller_fr.is_compiled_frame(), "what?");
2309 if (caller_fr.is_deoptimized_frame()) {
2310 log_info(exceptions)("deferred async exception at compiled safepoint");
2311 return;
2312 }
2313 }
2314 }
2315
2316 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2317 if (condition == _no_async_condition) {
2318 // Conditions have changed since has_special_runtime_exit_condition()
2319 // was called:
2320 // - if we were here only because of an external suspend request,
2321 // then that was taken care of above (or cancelled) so we are done
2322 // - if we were here because of another async request, then it has
2323 // been cleared between the has_special_runtime_exit_condition()
2324 // and now so again we are done
2325 return;
2326 }
2327
2328 // Check for pending async. exception
2329 if (_pending_async_exception != NULL) {
2330 // Only overwrite an already pending exception, if it is not a threadDeath.
2331 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2332
2333 // We cannot call Exceptions::_throw(...) here because we cannot block
2334 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2335
2336 LogTarget(Info, exceptions) lt;
2337 if (lt.is_enabled()) {
2338 ResourceMark rm;
2339 LogStream ls(lt);
2340 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2341 if (has_last_Java_frame()) {
2342 frame f = last_frame();
2343 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2344 }
2345 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2346 }
2347 _pending_async_exception = NULL;
2348 clear_has_async_exception();
2349 }
2350 }
2351
2352 if (check_unsafe_error &&
2353 condition == _async_unsafe_access_error && !has_pending_exception()) {
2354 condition = _no_async_condition; // done
2355 switch (thread_state()) {
2356 case _thread_in_vm: {
2357 JavaThread* THREAD = this;
2358 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2359 }
2360 case _thread_in_native: {
2361 ThreadInVMfromNative tiv(this);
2362 JavaThread* THREAD = this;
2363 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2364 }
2365 case _thread_in_Java: {
2366 ThreadInVMfromJava tiv(this);
2367 JavaThread* THREAD = this;
2368 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2369 }
2370 default:
2371 ShouldNotReachHere();
2372 }
2373 }
2374
2375 assert(condition == _no_async_condition || has_pending_exception() ||
2376 (!check_unsafe_error && condition == _async_unsafe_access_error),
2377 "must have handled the async condition, if no exception");
2378 }
2379
2380 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2381
2382 // Check for pending external suspend.
2383 if (is_external_suspend_with_lock()) {
2384 frame_anchor()->make_walkable(this);
2385 java_suspend_self_with_safepoint_check();
2386 }
2387
2388 // We might be here for reasons in addition to the self-suspend request
2389 // so check for other async requests.
2390 if (check_asyncs) {
2391 check_and_handle_async_exceptions();
2392 }
2393
2394 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2395 }
2396
2397 void JavaThread::send_thread_stop(oop java_throwable) {
2398 ResourceMark rm;
2399 assert(Thread::current()->is_VM_thread() || Thread::current() == this, "should be in the vm thread");
2400
2401 // Do not throw asynchronous exceptions against the compiler thread
2402 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2403 if (!can_call_java()) return;
2404
2405 {
2406 // Actually throw the Throwable against the target Thread - however
2407 // only if there is no thread death exception installed already.
2408 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2409 // If the topmost frame is a runtime stub, then we are calling into
2410 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2411 // must deoptimize the caller before continuing, as the compiled exception handler table
2412 // may not be valid
2413 if (has_last_Java_frame()) {
2414 frame f = last_frame();
2415 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2416 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2417 RegisterMap reg_map(this, UseBiasedLocking);
2418 frame compiled_frame = f.sender(®_map);
2419 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2420 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2421 }
2422 }
2423 }
2424
2425 // Set async. pending exception in thread.
2426 set_pending_async_exception(java_throwable);
2427
2428 if (log_is_enabled(Info, exceptions)) {
2429 ResourceMark rm;
2430 log_info(exceptions)("Pending Async. exception installed of type: %s",
2431 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2432 }
2433 // for AbortVMOnException flag
2434 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2435 }
2436 }
2437
2438
2439 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
2440 java_lang_Thread::set_interrupted(threadObj(), true);
2441 this->interrupt();
2442 }
2443
2444 // External suspension mechanism.
2445 //
2446 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2447 // to any VM_locks and it is at a transition
2448 // Self-suspension will happen on the transition out of the vm.
2449 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2450 //
2451 // Guarantees on return:
2452 // + Target thread will not execute any new bytecode (that's why we need to
2453 // force a safepoint)
2454 // + Target thread will not enter any new monitors
2455 //
2456 void JavaThread::java_suspend() {
2457 ThreadsListHandle tlh;
2458 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2459 return;
2460 }
2461
2462 { MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2463 if (!is_external_suspend()) {
2464 // a racing resume has cancelled us; bail out now
2465 return;
2466 }
2467
2468 // suspend is done
2469 uint32_t debug_bits = 0;
2470 // Warning: is_ext_suspend_completed() may temporarily drop the
2471 // SR_lock to allow the thread to reach a stable thread state if
2472 // it is currently in a transient thread state.
2473 if (is_ext_suspend_completed(false /* !called_by_wait */,
2474 SuspendRetryDelay, &debug_bits)) {
2475 return;
2476 }
2477 }
2478
2479 if (Thread::current() == this) {
2480 // Safely self-suspend.
2481 // If we don't do this explicitly it will implicitly happen
2482 // before we transition back to Java, and on some other thread-state
2483 // transition paths, but not as we exit a JVM TI SuspendThread call.
2484 // As SuspendThread(current) must not return (until resumed) we must
2485 // self-suspend here.
2486 ThreadBlockInVM tbivm(this);
2487 java_suspend_self();
2488 } else {
2489 VM_ThreadSuspend vm_suspend;
2490 VMThread::execute(&vm_suspend);
2491 }
2492 }
2493
2494 // Part II of external suspension.
2495 // A JavaThread self suspends when it detects a pending external suspend
2496 // request. This is usually on transitions. It is also done in places
2497 // where continuing to the next transition would surprise the caller,
2498 // e.g., monitor entry.
2499 //
2500 // Returns the number of times that the thread self-suspended.
2501 //
2502 // Note: DO NOT call java_suspend_self() when you just want to block current
2503 // thread. java_suspend_self() is the second stage of cooperative
2504 // suspension for external suspend requests and should only be used
2505 // to complete an external suspend request.
2506 //
2507 int JavaThread::java_suspend_self() {
2508 assert(thread_state() == _thread_blocked, "wrong state for java_suspend_self()");
2509 int ret = 0;
2510
2511 // we are in the process of exiting so don't suspend
2512 if (is_exiting()) {
2513 clear_external_suspend();
2514 return ret;
2515 }
2516
2517 assert(_anchor.walkable() ||
2518 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2519 "must have walkable stack");
2520
2521 MonitorLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2522
2523 assert(!this->is_ext_suspended(),
2524 "a thread trying to self-suspend should not already be suspended");
2525
2526 if (this->is_suspend_equivalent()) {
2527 // If we are self-suspending as a result of the lifting of a
2528 // suspend equivalent condition, then the suspend_equivalent
2529 // flag is not cleared until we set the ext_suspended flag so
2530 // that wait_for_ext_suspend_completion() returns consistent
2531 // results.
2532 this->clear_suspend_equivalent();
2533 }
2534
2535 // A racing resume may have cancelled us before we grabbed SR_lock
2536 // above. Or another external suspend request could be waiting for us
2537 // by the time we return from SR_lock()->wait(). The thread
2538 // that requested the suspension may already be trying to walk our
2539 // stack and if we return now, we can change the stack out from under
2540 // it. This would be a "bad thing (TM)" and cause the stack walker
2541 // to crash. We stay self-suspended until there are no more pending
2542 // external suspend requests.
2543 while (is_external_suspend()) {
2544 ret++;
2545 this->set_ext_suspended();
2546
2547 // _ext_suspended flag is cleared by java_resume()
2548 while (is_ext_suspended()) {
2549 ml.wait();
2550 }
2551 }
2552 return ret;
2553 }
2554
2555 // Helper routine to set up the correct thread state before calling java_suspend_self.
2556 // This is called when regular thread-state transition helpers can't be used because
2557 // we can be in various states, in particular _thread_in_native_trans.
2558 // Because this thread is external suspended the safepoint code will count it as at
2559 // a safepoint, regardless of what its actual current thread-state is. But
2560 // is_ext_suspend_completed() may be waiting to see a thread transition from
2561 // _thread_in_native_trans to _thread_blocked. So we set the thread state directly
2562 // to _thread_blocked. The problem with setting thread state directly is that a
2563 // safepoint could happen just after java_suspend_self() returns after being resumed,
2564 // and the VM thread will see the _thread_blocked state. So we must check for a safepoint
2565 // after restoring the state to make sure we won't leave while a safepoint is in progress.
2566 // However, not all initial-states are allowed when performing a safepoint check, as we
2567 // should never be blocking at a safepoint whilst in those states. Of these 'bad' states
2568 // only _thread_in_native is possible when executing this code (based on our two callers).
2569 // A thread that is _thread_in_native is already safepoint-safe and so it doesn't matter
2570 // whether the VMThread sees the _thread_blocked state, or the _thread_in_native state,
2571 // and so we don't need the explicit safepoint check.
2572
2573 void JavaThread::java_suspend_self_with_safepoint_check() {
2574 assert(this == Thread::current(), "invariant");
2575 JavaThreadState state = thread_state();
2576 set_thread_state(_thread_blocked);
2577 java_suspend_self();
2578 set_thread_state_fence(state);
2579 // Since we are not using a regular thread-state transition helper here,
2580 // we must manually emit the instruction barrier after leaving a safe state.
2581 OrderAccess::cross_modify_fence();
2582 if (state != _thread_in_native) {
2583 SafepointMechanism::block_if_requested(this);
2584 }
2585 }
2586
2587 #ifdef ASSERT
2588 // Verify the JavaThread has not yet been published in the Threads::list, and
2589 // hence doesn't need protection from concurrent access at this stage.
2590 void JavaThread::verify_not_published() {
2591 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2592 // since an unpublished JavaThread doesn't participate in the
2593 // Thread-SMR protocol for keeping a ThreadsList alive.
2594 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2595 }
2596 #endif
2597
2598 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2599 // progress or when _suspend_flags is non-zero.
2600 // Current thread needs to self-suspend if there is a suspend request and/or
2601 // block if a safepoint is in progress.
2602 // Async exception ISN'T checked.
2603 // Note only the ThreadInVMfromNative transition can call this function
2604 // directly and when thread state is _thread_in_native_trans
2605 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2606 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2607
2608 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2609
2610 if (thread->is_external_suspend()) {
2611 thread->java_suspend_self_with_safepoint_check();
2612 } else {
2613 SafepointMechanism::block_if_requested(thread);
2614 }
2615
2616 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2617 }
2618
2619 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2620 // progress or when _suspend_flags is non-zero.
2621 // Current thread needs to self-suspend if there is a suspend request and/or
2622 // block if a safepoint is in progress.
2623 // Also check for pending async exception (not including unsafe access error).
2624 // Note only the native==>VM/Java barriers can call this function and when
2625 // thread state is _thread_in_native_trans.
2626 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2627 check_safepoint_and_suspend_for_native_trans(thread);
2628
2629 if (thread->has_async_exception()) {
2630 // We are in _thread_in_native_trans state, don't handle unsafe
2631 // access error since that may block.
2632 thread->check_and_handle_async_exceptions(false);
2633 }
2634 }
2635
2636 // This is a variant of the normal
2637 // check_special_condition_for_native_trans with slightly different
2638 // semantics for use by critical native wrappers. It does all the
2639 // normal checks but also performs the transition back into
2640 // thread_in_Java state. This is required so that critical natives
2641 // can potentially block and perform a GC if they are the last thread
2642 // exiting the GCLocker.
2643 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2644 check_special_condition_for_native_trans(thread);
2645
2646 // Finish the transition
2647 thread->set_thread_state(_thread_in_Java);
2648
2649 if (thread->do_critical_native_unlock()) {
2650 ThreadInVMfromJavaNoAsyncException tiv(thread);
2651 GCLocker::unlock_critical(thread);
2652 thread->clear_critical_native_unlock();
2653 }
2654 }
2655
2656 // We need to guarantee the Threads_lock here, since resumes are not
2657 // allowed during safepoint synchronization
2658 // Can only resume from an external suspension
2659 void JavaThread::java_resume() {
2660 assert_locked_or_safepoint(Threads_lock);
2661
2662 // Sanity check: thread is gone, has started exiting or the thread
2663 // was not externally suspended.
2664 ThreadsListHandle tlh;
2665 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2666 return;
2667 }
2668
2669 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2670
2671 clear_external_suspend();
2672
2673 if (is_ext_suspended()) {
2674 clear_ext_suspended();
2675 SR_lock()->notify_all();
2676 }
2677 }
2678
2679 size_t JavaThread::_stack_red_zone_size = 0;
2680 size_t JavaThread::_stack_yellow_zone_size = 0;
2681 size_t JavaThread::_stack_reserved_zone_size = 0;
2682 size_t JavaThread::_stack_shadow_zone_size = 0;
2683
2684 void JavaThread::create_stack_guard_pages() {
2685 if (!os::uses_stack_guard_pages() ||
2686 _stack_guard_state != stack_guard_unused ||
2687 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2688 log_info(os, thread)("Stack guard page creation for thread "
2689 UINTX_FORMAT " disabled", os::current_thread_id());
2690 return;
2691 }
2692 address low_addr = stack_end();
2693 size_t len = stack_guard_zone_size();
2694
2695 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2696 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2697
2698 int must_commit = os::must_commit_stack_guard_pages();
2699 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2700
2701 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2702 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2703 return;
2704 }
2705
2706 if (os::guard_memory((char *) low_addr, len)) {
2707 _stack_guard_state = stack_guard_enabled;
2708 } else {
2709 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2710 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2711 if (os::uncommit_memory((char *) low_addr, len)) {
2712 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2713 }
2714 return;
2715 }
2716
2717 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2718 PTR_FORMAT "-" PTR_FORMAT ".",
2719 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2720 }
2721
2722 void JavaThread::remove_stack_guard_pages() {
2723 assert(Thread::current() == this, "from different thread");
2724 if (_stack_guard_state == stack_guard_unused) return;
2725 address low_addr = stack_end();
2726 size_t len = stack_guard_zone_size();
2727
2728 if (os::must_commit_stack_guard_pages()) {
2729 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2730 _stack_guard_state = stack_guard_unused;
2731 } else {
2732 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2733 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2734 return;
2735 }
2736 } else {
2737 if (_stack_guard_state == stack_guard_unused) return;
2738 if (os::unguard_memory((char *) low_addr, len)) {
2739 _stack_guard_state = stack_guard_unused;
2740 } else {
2741 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2742 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2743 return;
2744 }
2745 }
2746
2747 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2748 PTR_FORMAT "-" PTR_FORMAT ".",
2749 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2750 }
2751
2752 void JavaThread::enable_stack_reserved_zone() {
2753 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state");
2754
2755 // The base notation is from the stack's point of view, growing downward.
2756 // We need to adjust it to work correctly with guard_memory()
2757 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2758
2759 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2760 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2761
2762 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2763 _stack_guard_state = stack_guard_enabled;
2764 } else {
2765 warning("Attempt to guard stack reserved zone failed.");
2766 }
2767 enable_register_stack_guard();
2768 }
2769
2770 void JavaThread::disable_stack_reserved_zone() {
2771 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state");
2772
2773 // Simply return if called for a thread that does not use guard pages.
2774 if (_stack_guard_state != stack_guard_enabled) return;
2775
2776 // The base notation is from the stack's point of view, growing downward.
2777 // We need to adjust it to work correctly with guard_memory()
2778 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2779
2780 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2781 _stack_guard_state = stack_guard_reserved_disabled;
2782 } else {
2783 warning("Attempt to unguard stack reserved zone failed.");
2784 }
2785 disable_register_stack_guard();
2786 }
2787
2788 void JavaThread::enable_stack_yellow_reserved_zone() {
2789 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2790 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2791
2792 // The base notation is from the stacks point of view, growing downward.
2793 // We need to adjust it to work correctly with guard_memory()
2794 address base = stack_red_zone_base();
2795
2796 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2797 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2798
2799 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2800 _stack_guard_state = stack_guard_enabled;
2801 } else {
2802 warning("Attempt to guard stack yellow zone failed.");
2803 }
2804 enable_register_stack_guard();
2805 }
2806
2807 void JavaThread::disable_stack_yellow_reserved_zone() {
2808 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2809 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2810
2811 // Simply return if called for a thread that does not use guard pages.
2812 if (_stack_guard_state == stack_guard_unused) return;
2813
2814 // The base notation is from the stacks point of view, growing downward.
2815 // We need to adjust it to work correctly with guard_memory()
2816 address base = stack_red_zone_base();
2817
2818 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2819 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2820 } else {
2821 warning("Attempt to unguard stack yellow zone failed.");
2822 }
2823 disable_register_stack_guard();
2824 }
2825
2826 void JavaThread::enable_stack_red_zone() {
2827 // The base notation is from the stacks point of view, growing downward.
2828 // We need to adjust it to work correctly with guard_memory()
2829 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2830 address base = stack_red_zone_base() - stack_red_zone_size();
2831
2832 guarantee(base < stack_base(), "Error calculating stack red zone");
2833 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2834
2835 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2836 warning("Attempt to guard stack red zone failed.");
2837 }
2838 }
2839
2840 void JavaThread::disable_stack_red_zone() {
2841 // The base notation is from the stacks point of view, growing downward.
2842 // We need to adjust it to work correctly with guard_memory()
2843 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2844 address base = stack_red_zone_base() - stack_red_zone_size();
2845 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2846 warning("Attempt to unguard stack red zone failed.");
2847 }
2848 }
2849
2850 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2851 // ignore is there is no stack
2852 if (!has_last_Java_frame()) return;
2853 // traverse the stack frames. Starts from top frame.
2854 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2855 frame* fr = fst.current();
2856 f(fr, fst.register_map());
2857 }
2858 }
2859
2860
2861 #ifndef PRODUCT
2862 // Deoptimization
2863 // Function for testing deoptimization
2864 void JavaThread::deoptimize() {
2865 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2866 StackFrameStream fst(this, UseBiasedLocking);
2867 bool deopt = false; // Dump stack only if a deopt actually happens.
2868 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2869 // Iterate over all frames in the thread and deoptimize
2870 for (; !fst.is_done(); fst.next()) {
2871 if (fst.current()->can_be_deoptimized()) {
2872
2873 if (only_at) {
2874 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2875 // consists of comma or carriage return separated numbers so
2876 // search for the current bci in that string.
2877 address pc = fst.current()->pc();
2878 nmethod* nm = (nmethod*) fst.current()->cb();
2879 ScopeDesc* sd = nm->scope_desc_at(pc);
2880 char buffer[8];
2881 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2882 size_t len = strlen(buffer);
2883 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2884 while (found != NULL) {
2885 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2886 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2887 // Check that the bci found is bracketed by terminators.
2888 break;
2889 }
2890 found = strstr(found + 1, buffer);
2891 }
2892 if (!found) {
2893 continue;
2894 }
2895 }
2896
2897 if (DebugDeoptimization && !deopt) {
2898 deopt = true; // One-time only print before deopt
2899 tty->print_cr("[BEFORE Deoptimization]");
2900 trace_frames();
2901 trace_stack();
2902 }
2903 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2904 }
2905 }
2906
2907 if (DebugDeoptimization && deopt) {
2908 tty->print_cr("[AFTER Deoptimization]");
2909 trace_frames();
2910 }
2911 }
2912
2913
2914 // Make zombies
2915 void JavaThread::make_zombies() {
2916 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2917 if (fst.current()->can_be_deoptimized()) {
2918 // it is a Java nmethod
2919 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2920 nm->make_not_entrant();
2921 }
2922 }
2923 }
2924 #endif // PRODUCT
2925
2926
2927 void JavaThread::deoptimize_marked_methods() {
2928 if (!has_last_Java_frame()) return;
2929 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2930 StackFrameStream fst(this, UseBiasedLocking);
2931 for (; !fst.is_done(); fst.next()) {
2932 if (fst.current()->should_be_deoptimized()) {
2933 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2934 }
2935 }
2936 }
2937
2938 // If the caller is a NamedThread, then remember, in the current scope,
2939 // the given JavaThread in its _processed_thread field.
2940 class RememberProcessedThread: public StackObj {
2941 NamedThread* _cur_thr;
2942 public:
2943 RememberProcessedThread(JavaThread* jthr) {
2944 Thread* thread = Thread::current();
2945 if (thread->is_Named_thread()) {
2946 _cur_thr = (NamedThread *)thread;
2947 _cur_thr->set_processed_thread(jthr);
2948 } else {
2949 _cur_thr = NULL;
2950 }
2951 }
2952
2953 ~RememberProcessedThread() {
2954 if (_cur_thr) {
2955 _cur_thr->set_processed_thread(NULL);
2956 }
2957 }
2958 };
2959
2960 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2961 // Verify that the deferred card marks have been flushed.
2962 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2963
2964 // Traverse the GCHandles
2965 Thread::oops_do(f, cf);
2966
2967 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2968 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2969
2970 if (has_last_Java_frame()) {
2971 // Record JavaThread to GC thread
2972 RememberProcessedThread rpt(this);
2973
2974 // traverse the registered growable array
2975 if (_array_for_gc != NULL) {
2976 for (int index = 0; index < _array_for_gc->length(); index++) {
2977 f->do_oop(_array_for_gc->adr_at(index));
2978 }
2979 }
2980
2981 // Traverse the monitor chunks
2982 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2983 chunk->oops_do(f);
2984 }
2985
2986 // Traverse the execution stack
2987 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2988 fst.current()->oops_do(f, cf, fst.register_map());
2989 }
2990 }
2991
2992 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2993 // If we have deferred set_locals there might be oops waiting to be
2994 // written
2995 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2996 if (list != NULL) {
2997 for (int i = 0; i < list->length(); i++) {
2998 list->at(i)->oops_do(f);
2999 }
3000 }
3001
3002 // Traverse instance variables at the end since the GC may be moving things
3003 // around using this function
3004 f->do_oop((oop*) &_threadObj);
3005 f->do_oop((oop*) &_vm_result);
3006 f->do_oop((oop*) &_exception_oop);
3007 f->do_oop((oop*) &_pending_async_exception);
3008
3009 if (jvmti_thread_state() != NULL) {
3010 jvmti_thread_state()->oops_do(f, cf);
3011 }
3012 }
3013
3014 #ifdef ASSERT
3015 void JavaThread::verify_states_for_handshake() {
3016 // This checks that the thread has a correct frame state during a handshake.
3017 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
3018 (has_last_Java_frame() && java_call_counter() > 0),
3019 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
3020 has_last_Java_frame(), java_call_counter());
3021 }
3022 #endif
3023
3024 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
3025 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
3026 (has_last_Java_frame() && java_call_counter() > 0),
3027 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
3028 has_last_Java_frame(), java_call_counter());
3029
3030 if (has_last_Java_frame()) {
3031 // Traverse the execution stack
3032 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3033 fst.current()->nmethods_do(cf);
3034 }
3035 }
3036
3037 if (jvmti_thread_state() != NULL) {
3038 jvmti_thread_state()->nmethods_do(cf);
3039 }
3040 }
3041
3042 void JavaThread::metadata_do(MetadataClosure* f) {
3043 if (has_last_Java_frame()) {
3044 // Traverse the execution stack to call f() on the methods in the stack
3045 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3046 fst.current()->metadata_do(f);
3047 }
3048 } else if (is_Compiler_thread()) {
3049 // need to walk ciMetadata in current compile tasks to keep alive.
3050 CompilerThread* ct = (CompilerThread*)this;
3051 if (ct->env() != NULL) {
3052 ct->env()->metadata_do(f);
3053 }
3054 CompileTask* task = ct->task();
3055 if (task != NULL) {
3056 task->metadata_do(f);
3057 }
3058 }
3059 }
3060
3061 // Printing
3062 const char* _get_thread_state_name(JavaThreadState _thread_state) {
3063 switch (_thread_state) {
3064 case _thread_uninitialized: return "_thread_uninitialized";
3065 case _thread_new: return "_thread_new";
3066 case _thread_new_trans: return "_thread_new_trans";
3067 case _thread_in_native: return "_thread_in_native";
3068 case _thread_in_native_trans: return "_thread_in_native_trans";
3069 case _thread_in_vm: return "_thread_in_vm";
3070 case _thread_in_vm_trans: return "_thread_in_vm_trans";
3071 case _thread_in_Java: return "_thread_in_Java";
3072 case _thread_in_Java_trans: return "_thread_in_Java_trans";
3073 case _thread_blocked: return "_thread_blocked";
3074 case _thread_blocked_trans: return "_thread_blocked_trans";
3075 default: return "unknown thread state";
3076 }
3077 }
3078
3079 #ifndef PRODUCT
3080 void JavaThread::print_thread_state_on(outputStream *st) const {
3081 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
3082 };
3083 #endif // PRODUCT
3084
3085 // Called by Threads::print() for VM_PrintThreads operation
3086 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
3087 st->print_raw("\"");
3088 st->print_raw(get_thread_name());
3089 st->print_raw("\" ");
3090 oop thread_oop = threadObj();
3091 if (thread_oop != NULL) {
3092 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
3093 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
3094 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
3095 }
3096 Thread::print_on(st, print_extended_info);
3097 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
3098 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
3099 if (thread_oop != NULL) {
3100 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3101 }
3102 #ifndef PRODUCT
3103 _safepoint_state->print_on(st);
3104 #endif // PRODUCT
3105 if (is_Compiler_thread()) {
3106 CompileTask *task = ((CompilerThread*)this)->task();
3107 if (task != NULL) {
3108 st->print(" Compiling: ");
3109 task->print(st, NULL, true, false);
3110 } else {
3111 st->print(" No compile task");
3112 }
3113 st->cr();
3114 }
3115 }
3116
3117 void JavaThread::print() const { print_on(tty); }
3118
3119 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3120 st->print("%s", get_thread_name_string(buf, buflen));
3121 }
3122
3123 // Called by fatal error handler. The difference between this and
3124 // JavaThread::print() is that we can't grab lock or allocate memory.
3125 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3126 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3127 oop thread_obj = threadObj();
3128 if (thread_obj != NULL) {
3129 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3130 }
3131 st->print(" [");
3132 st->print("%s", _get_thread_state_name(_thread_state));
3133 if (osthread()) {
3134 st->print(", id=%d", osthread()->thread_id());
3135 }
3136 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3137 p2i(stack_end()), p2i(stack_base()));
3138 st->print("]");
3139
3140 ThreadsSMRSupport::print_info_on(this, st);
3141 return;
3142 }
3143
3144 // Verification
3145
3146 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3147
3148 void JavaThread::verify() {
3149 // Verify oops in the thread.
3150 oops_do(&VerifyOopClosure::verify_oop, NULL);
3151
3152 // Verify the stack frames.
3153 frames_do(frame_verify);
3154 }
3155
3156 // CR 6300358 (sub-CR 2137150)
3157 // Most callers of this method assume that it can't return NULL but a
3158 // thread may not have a name whilst it is in the process of attaching to
3159 // the VM - see CR 6412693, and there are places where a JavaThread can be
3160 // seen prior to having it's threadObj set (eg JNI attaching threads and
3161 // if vm exit occurs during initialization). These cases can all be accounted
3162 // for such that this method never returns NULL.
3163 const char* JavaThread::get_thread_name() const {
3164 #ifdef ASSERT
3165 // early safepoints can hit while current thread does not yet have TLS
3166 if (!SafepointSynchronize::is_at_safepoint()) {
3167 Thread *cur = Thread::current();
3168 if (!(cur->is_Java_thread() && cur == this)) {
3169 // Current JavaThreads are allowed to get their own name without
3170 // the Threads_lock.
3171 assert_locked_or_safepoint_or_handshake(Threads_lock, this);
3172 }
3173 }
3174 #endif // ASSERT
3175 return get_thread_name_string();
3176 }
3177
3178 // Returns a non-NULL representation of this thread's name, or a suitable
3179 // descriptive string if there is no set name
3180 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3181 const char* name_str;
3182 oop thread_obj = threadObj();
3183 if (thread_obj != NULL) {
3184 oop name = java_lang_Thread::name(thread_obj);
3185 if (name != NULL) {
3186 if (buf == NULL) {
3187 name_str = java_lang_String::as_utf8_string(name);
3188 } else {
3189 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3190 }
3191 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3192 name_str = "<no-name - thread is attaching>";
3193 } else {
3194 name_str = Thread::name();
3195 }
3196 } else {
3197 name_str = Thread::name();
3198 }
3199 assert(name_str != NULL, "unexpected NULL thread name");
3200 return name_str;
3201 }
3202
3203 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3204
3205 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3206 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
3207 // Link Java Thread object <-> C++ Thread
3208
3209 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3210 // and put it into a new Handle. The Handle "thread_oop" can then
3211 // be used to pass the C++ thread object to other methods.
3212
3213 // Set the Java level thread object (jthread) field of the
3214 // new thread (a JavaThread *) to C++ thread object using the
3215 // "thread_oop" handle.
3216
3217 // Set the thread field (a JavaThread *) of the
3218 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3219
3220 Handle thread_oop(Thread::current(),
3221 JNIHandles::resolve_non_null(jni_thread));
3222 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3223 "must be initialized");
3224 set_threadObj(thread_oop());
3225 java_lang_Thread::set_thread(thread_oop(), this);
3226
3227 if (prio == NoPriority) {
3228 prio = java_lang_Thread::priority(thread_oop());
3229 assert(prio != NoPriority, "A valid priority should be present");
3230 }
3231
3232 // Push the Java priority down to the native thread; needs Threads_lock
3233 Thread::set_priority(this, prio);
3234
3235 // Add the new thread to the Threads list and set it in motion.
3236 // We must have threads lock in order to call Threads::add.
3237 // It is crucial that we do not block before the thread is
3238 // added to the Threads list for if a GC happens, then the java_thread oop
3239 // will not be visited by GC.
3240 Threads::add(this);
3241 }
3242
3243 oop JavaThread::current_park_blocker() {
3244 // Support for JSR-166 locks
3245 oop thread_oop = threadObj();
3246 if (thread_oop != NULL) {
3247 return java_lang_Thread::park_blocker(thread_oop);
3248 }
3249 return NULL;
3250 }
3251
3252
3253 void JavaThread::print_stack_on(outputStream* st) {
3254 if (!has_last_Java_frame()) return;
3255 ResourceMark rm;
3256 HandleMark hm;
3257
3258 RegisterMap reg_map(this);
3259 vframe* start_vf = last_java_vframe(®_map);
3260 int count = 0;
3261 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3262 if (f->is_java_frame()) {
3263 javaVFrame* jvf = javaVFrame::cast(f);
3264 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3265
3266 // Print out lock information
3267 if (JavaMonitorsInStackTrace) {
3268 jvf->print_lock_info_on(st, count);
3269 }
3270 } else {
3271 // Ignore non-Java frames
3272 }
3273
3274 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3275 count++;
3276 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3277 }
3278 }
3279
3280
3281 // JVMTI PopFrame support
3282 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3283 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3284 if (in_bytes(size_in_bytes) != 0) {
3285 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3286 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3287 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3288 }
3289 }
3290
3291 void* JavaThread::popframe_preserved_args() {
3292 return _popframe_preserved_args;
3293 }
3294
3295 ByteSize JavaThread::popframe_preserved_args_size() {
3296 return in_ByteSize(_popframe_preserved_args_size);
3297 }
3298
3299 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3300 int sz = in_bytes(popframe_preserved_args_size());
3301 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3302 return in_WordSize(sz / wordSize);
3303 }
3304
3305 void JavaThread::popframe_free_preserved_args() {
3306 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3307 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
3308 _popframe_preserved_args = NULL;
3309 _popframe_preserved_args_size = 0;
3310 }
3311
3312 #ifndef PRODUCT
3313
3314 void JavaThread::trace_frames() {
3315 tty->print_cr("[Describe stack]");
3316 int frame_no = 1;
3317 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3318 tty->print(" %d. ", frame_no++);
3319 fst.current()->print_value_on(tty, this);
3320 tty->cr();
3321 }
3322 }
3323
3324 class PrintAndVerifyOopClosure: public OopClosure {
3325 protected:
3326 template <class T> inline void do_oop_work(T* p) {
3327 oop obj = RawAccess<>::oop_load(p);
3328 if (obj == NULL) return;
3329 tty->print(INTPTR_FORMAT ": ", p2i(p));
3330 if (oopDesc::is_oop_or_null(obj)) {
3331 if (obj->is_objArray()) {
3332 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3333 } else {
3334 obj->print();
3335 }
3336 } else {
3337 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3338 }
3339 tty->cr();
3340 }
3341 public:
3342 virtual void do_oop(oop* p) { do_oop_work(p); }
3343 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3344 };
3345
3346 #ifdef ASSERT
3347 // Print or validate the layout of stack frames
3348 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3349 ResourceMark rm;
3350 PRESERVE_EXCEPTION_MARK;
3351 FrameValues values;
3352 int frame_no = 0;
3353 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3354 fst.current()->describe(values, ++frame_no);
3355 if (depth == frame_no) break;
3356 }
3357 if (validate_only) {
3358 values.validate();
3359 } else {
3360 tty->print_cr("[Describe stack layout]");
3361 values.print(this);
3362 }
3363 }
3364 #endif
3365
3366 void JavaThread::trace_stack_from(vframe* start_vf) {
3367 ResourceMark rm;
3368 int vframe_no = 1;
3369 for (vframe* f = start_vf; f; f = f->sender()) {
3370 if (f->is_java_frame()) {
3371 javaVFrame::cast(f)->print_activation(vframe_no++);
3372 } else {
3373 f->print();
3374 }
3375 if (vframe_no > StackPrintLimit) {
3376 tty->print_cr("...<more frames>...");
3377 return;
3378 }
3379 }
3380 }
3381
3382
3383 void JavaThread::trace_stack() {
3384 if (!has_last_Java_frame()) return;
3385 ResourceMark rm;
3386 HandleMark hm;
3387 RegisterMap reg_map(this);
3388 trace_stack_from(last_java_vframe(®_map));
3389 }
3390
3391
3392 #endif // PRODUCT
3393
3394
3395 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3396 assert(reg_map != NULL, "a map must be given");
3397 frame f = last_frame();
3398 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3399 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3400 }
3401 return NULL;
3402 }
3403
3404
3405 Klass* JavaThread::security_get_caller_class(int depth) {
3406 vframeStream vfst(this);
3407 vfst.security_get_caller_frame(depth);
3408 if (!vfst.at_end()) {
3409 return vfst.method()->method_holder();
3410 }
3411 return NULL;
3412 }
3413
3414 // java.lang.Thread.sleep support
3415 // Returns true if sleep time elapsed as expected, and false
3416 // if the thread was interrupted.
3417 bool JavaThread::sleep(jlong millis) {
3418 assert(this == Thread::current(), "thread consistency check");
3419
3420 ParkEvent * const slp = this->_SleepEvent;
3421 // Because there can be races with thread interruption sending an unpark()
3422 // to the event, we explicitly reset it here to avoid an immediate return.
3423 // The actual interrupt state will be checked before we park().
3424 slp->reset();
3425 // Thread interruption establishes a happens-before ordering in the
3426 // Java Memory Model, so we need to ensure we synchronize with the
3427 // interrupt state.
3428 OrderAccess::fence();
3429
3430 jlong prevtime = os::javaTimeNanos();
3431
3432 for (;;) {
3433 // interruption has precedence over timing out
3434 if (this->is_interrupted(true)) {
3435 return false;
3436 }
3437
3438 if (millis <= 0) {
3439 return true;
3440 }
3441
3442 {
3443 ThreadBlockInVM tbivm(this);
3444 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
3445
3446 this->set_suspend_equivalent();
3447 // cleared by handle_special_suspend_equivalent_condition() or
3448 // java_suspend_self() via check_and_wait_while_suspended()
3449
3450 slp->park(millis);
3451
3452 // were we externally suspended while we were waiting?
3453 this->check_and_wait_while_suspended();
3454 }
3455
3456 // Update elapsed time tracking
3457 jlong newtime = os::javaTimeNanos();
3458 if (newtime - prevtime < 0) {
3459 // time moving backwards, should only happen if no monotonic clock
3460 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3461 assert(!os::supports_monotonic_clock(),
3462 "unexpected time moving backwards detected in JavaThread::sleep()");
3463 } else {
3464 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3465 }
3466 prevtime = newtime;
3467 }
3468 }
3469
3470 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3471 assert(thread->is_Compiler_thread(), "must be compiler thread");
3472 CompileBroker::compiler_thread_loop();
3473 }
3474
3475 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3476 NMethodSweeper::sweeper_loop();
3477 }
3478
3479 // Create a CompilerThread
3480 CompilerThread::CompilerThread(CompileQueue* queue,
3481 CompilerCounters* counters)
3482 : JavaThread(&compiler_thread_entry) {
3483 _env = NULL;
3484 _log = NULL;
3485 _task = NULL;
3486 _queue = queue;
3487 _counters = counters;
3488 _buffer_blob = NULL;
3489 _compiler = NULL;
3490
3491 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3492 resource_area()->bias_to(mtCompiler);
3493
3494 #ifndef PRODUCT
3495 _ideal_graph_printer = NULL;
3496 #endif
3497 }
3498
3499 CompilerThread::~CompilerThread() {
3500 // Delete objects which were allocated on heap.
3501 delete _counters;
3502 }
3503
3504 bool CompilerThread::can_call_java() const {
3505 return _compiler != NULL && _compiler->is_jvmci();
3506 }
3507
3508 // Create sweeper thread
3509 CodeCacheSweeperThread::CodeCacheSweeperThread()
3510 : JavaThread(&sweeper_thread_entry) {
3511 _scanned_compiled_method = NULL;
3512 }
3513
3514 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3515 JavaThread::oops_do(f, cf);
3516 if (_scanned_compiled_method != NULL && cf != NULL) {
3517 // Safepoints can occur when the sweeper is scanning an nmethod so
3518 // process it here to make sure it isn't unloaded in the middle of
3519 // a scan.
3520 cf->do_code_blob(_scanned_compiled_method);
3521 }
3522 }
3523
3524 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3525 JavaThread::nmethods_do(cf);
3526 if (_scanned_compiled_method != NULL && cf != NULL) {
3527 // Safepoints can occur when the sweeper is scanning an nmethod so
3528 // process it here to make sure it isn't unloaded in the middle of
3529 // a scan.
3530 cf->do_code_blob(_scanned_compiled_method);
3531 }
3532 }
3533
3534
3535 // ======= Threads ========
3536
3537 // The Threads class links together all active threads, and provides
3538 // operations over all threads. It is protected by the Threads_lock,
3539 // which is also used in other global contexts like safepointing.
3540 // ThreadsListHandles are used to safely perform operations on one
3541 // or more threads without the risk of the thread exiting during the
3542 // operation.
3543 //
3544 // Note: The Threads_lock is currently more widely used than we
3545 // would like. We are actively migrating Threads_lock uses to other
3546 // mechanisms in order to reduce Threads_lock contention.
3547
3548 int Threads::_number_of_threads = 0;
3549 int Threads::_number_of_non_daemon_threads = 0;
3550 int Threads::_return_code = 0;
3551 uintx Threads::_thread_claim_token = 1; // Never zero.
3552 size_t JavaThread::_stack_size_at_create = 0;
3553
3554 #ifdef ASSERT
3555 bool Threads::_vm_complete = false;
3556 #endif
3557
3558 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3559 Prefetch::read((void*)addr, prefetch_interval);
3560 return *addr;
3561 }
3562
3563 // Possibly the ugliest for loop the world has seen. C++ does not allow
3564 // multiple types in the declaration section of the for loop. In this case
3565 // we are only dealing with pointers and hence can cast them. It looks ugly
3566 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3567 #define DO_JAVA_THREADS(LIST, X) \
3568 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3569 *MACRO_list = (JavaThread*)(LIST), \
3570 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3571 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3572 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3573 MACRO_current_p != MACRO_end; \
3574 MACRO_current_p++, \
3575 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3576
3577 // All JavaThreads
3578 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3579
3580 // All NonJavaThreads (i.e., every non-JavaThread in the system).
3581 void Threads::non_java_threads_do(ThreadClosure* tc) {
3582 NoSafepointVerifier nsv;
3583 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
3584 tc->do_thread(njti.current());
3585 }
3586 }
3587
3588 // All JavaThreads
3589 void Threads::java_threads_do(ThreadClosure* tc) {
3590 assert_locked_or_safepoint(Threads_lock);
3591 // ALL_JAVA_THREADS iterates through all JavaThreads.
3592 ALL_JAVA_THREADS(p) {
3593 tc->do_thread(p);
3594 }
3595 }
3596
3597 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3598 assert_locked_or_safepoint(Threads_lock);
3599 java_threads_do(tc);
3600 tc->do_thread(VMThread::vm_thread());
3601 }
3602
3603 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3604 void Threads::threads_do(ThreadClosure* tc) {
3605 assert_locked_or_safepoint(Threads_lock);
3606 java_threads_do(tc);
3607 non_java_threads_do(tc);
3608 }
3609
3610 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3611 uintx claim_token = Threads::thread_claim_token();
3612 ALL_JAVA_THREADS(p) {
3613 if (p->claim_threads_do(is_par, claim_token)) {
3614 tc->do_thread(p);
3615 }
3616 }
3617 VMThread* vmt = VMThread::vm_thread();
3618 if (vmt->claim_threads_do(is_par, claim_token)) {
3619 tc->do_thread(vmt);
3620 }
3621 }
3622
3623 // The system initialization in the library has three phases.
3624 //
3625 // Phase 1: java.lang.System class initialization
3626 // java.lang.System is a primordial class loaded and initialized
3627 // by the VM early during startup. java.lang.System.<clinit>
3628 // only does registerNatives and keeps the rest of the class
3629 // initialization work later until thread initialization completes.
3630 //
3631 // System.initPhase1 initializes the system properties, the static
3632 // fields in, out, and err. Set up java signal handlers, OS-specific
3633 // system settings, and thread group of the main thread.
3634 static void call_initPhase1(TRAPS) {
3635 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3636 JavaValue result(T_VOID);
3637 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3638 vmSymbols::void_method_signature(), CHECK);
3639 }
3640
3641 // Phase 2. Module system initialization
3642 // This will initialize the module system. Only java.base classes
3643 // can be loaded until phase 2 completes.
3644 //
3645 // Call System.initPhase2 after the compiler initialization and jsr292
3646 // classes get initialized because module initialization runs a lot of java
3647 // code, that for performance reasons, should be compiled. Also, this will
3648 // enable the startup code to use lambda and other language features in this
3649 // phase and onward.
3650 //
3651 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3652 static void call_initPhase2(TRAPS) {
3653 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3654
3655 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3656
3657 JavaValue result(T_INT);
3658 JavaCallArguments args;
3659 args.push_int(DisplayVMOutputToStderr);
3660 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3661 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3662 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3663 if (result.get_jint() != JNI_OK) {
3664 vm_exit_during_initialization(); // no message or exception
3665 }
3666
3667 universe_post_module_init();
3668 }
3669
3670 // Phase 3. final setup - set security manager, system class loader and TCCL
3671 //
3672 // This will instantiate and set the security manager, set the system class
3673 // loader as well as the thread context class loader. The security manager
3674 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3675 // other modules or the application's classpath.
3676 static void call_initPhase3(TRAPS) {
3677 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3678 JavaValue result(T_VOID);
3679 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3680 vmSymbols::void_method_signature(), CHECK);
3681 }
3682
3683 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3684 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3685
3686 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3687 create_vm_init_libraries();
3688 }
3689
3690 initialize_class(vmSymbols::java_lang_String(), CHECK);
3691
3692 // Inject CompactStrings value after the static initializers for String ran.
3693 java_lang_String::set_compact_strings(CompactStrings);
3694
3695 // Initialize java_lang.System (needed before creating the thread)
3696 initialize_class(vmSymbols::java_lang_System(), CHECK);
3697 // The VM creates & returns objects of this class. Make sure it's initialized.
3698 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3699 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3700 Handle thread_group = create_initial_thread_group(CHECK);
3701 Universe::set_main_thread_group(thread_group());
3702 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3703 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3704 main_thread->set_threadObj(thread_object);
3705
3706 // Set thread status to running since main thread has
3707 // been started and running.
3708 java_lang_Thread::set_thread_status(thread_object,
3709 java_lang_Thread::RUNNABLE);
3710
3711 // The VM creates objects of this class.
3712 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3713
3714 #ifdef ASSERT
3715 InstanceKlass *k = SystemDictionary::UnsafeConstants_klass();
3716 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
3717 #endif
3718
3719 // initialize the hardware-specific constants needed by Unsafe
3720 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
3721 jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
3722
3723 // The VM preresolves methods to these classes. Make sure that they get initialized
3724 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3725 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3726
3727 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3728 call_initPhase1(CHECK);
3729
3730 // get the Java runtime name, version, and vendor info after java.lang.System is initialized
3731 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3732 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3733 JDK_Version::set_runtime_vendor_version(get_java_runtime_vendor_version(THREAD));
3734 JDK_Version::set_runtime_vendor_vm_bug_url(get_java_runtime_vendor_vm_bug_url(THREAD));
3735
3736 // an instance of OutOfMemory exception has been allocated earlier
3737 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3738 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3739 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3740 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3741 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3742 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3743 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3744 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3745
3746 // Eager box cache initialization only if AOT is on and any library is loaded.
3747 AOTLoader::initialize_box_caches(CHECK);
3748 }
3749
3750 void Threads::initialize_jsr292_core_classes(TRAPS) {
3751 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3752
3753 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3754 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3755 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3756 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3757 }
3758
3759 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3760 extern void JDK_Version_init();
3761
3762 // Preinitialize version info.
3763 VM_Version::early_initialize();
3764
3765 // Check version
3766 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3767
3768 // Initialize library-based TLS
3769 ThreadLocalStorage::init();
3770
3771 // Initialize the output stream module
3772 ostream_init();
3773
3774 // Process java launcher properties.
3775 Arguments::process_sun_java_launcher_properties(args);
3776
3777 // Initialize the os module
3778 os::init();
3779
3780 // Record VM creation timing statistics
3781 TraceVmCreationTime create_vm_timer;
3782 create_vm_timer.start();
3783
3784 // Initialize system properties.
3785 Arguments::init_system_properties();
3786
3787 // So that JDK version can be used as a discriminator when parsing arguments
3788 JDK_Version_init();
3789
3790 // Update/Initialize System properties after JDK version number is known
3791 Arguments::init_version_specific_system_properties();
3792
3793 // Make sure to initialize log configuration *before* parsing arguments
3794 LogConfiguration::initialize(create_vm_timer.begin_time());
3795
3796 // Parse arguments
3797 // Note: this internally calls os::init_container_support()
3798 jint parse_result = Arguments::parse(args);
3799 if (parse_result != JNI_OK) return parse_result;
3800
3801 os::init_before_ergo();
3802
3803 jint ergo_result = Arguments::apply_ergo();
3804 if (ergo_result != JNI_OK) return ergo_result;
3805
3806 // Final check of all ranges after ergonomics which may change values.
3807 if (!JVMFlagRangeList::check_ranges()) {
3808 return JNI_EINVAL;
3809 }
3810
3811 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3812 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo);
3813 if (!constraint_result) {
3814 return JNI_EINVAL;
3815 }
3816
3817 if (PauseAtStartup) {
3818 os::pause();
3819 }
3820
3821 HOTSPOT_VM_INIT_BEGIN();
3822
3823 // Timing (must come after argument parsing)
3824 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3825
3826 // Initialize the os module after parsing the args
3827 jint os_init_2_result = os::init_2();
3828 if (os_init_2_result != JNI_OK) return os_init_2_result;
3829
3830 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3831 // Initialize assert poison page mechanism.
3832 if (ShowRegistersOnAssert) {
3833 initialize_assert_poison();
3834 }
3835 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3836
3837 SafepointMechanism::initialize();
3838
3839 jint adjust_after_os_result = Arguments::adjust_after_os();
3840 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3841
3842 // Initialize output stream logging
3843 ostream_init_log();
3844
3845 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3846 // Must be before create_vm_init_agents()
3847 if (Arguments::init_libraries_at_startup()) {
3848 convert_vm_init_libraries_to_agents();
3849 }
3850
3851 // Launch -agentlib/-agentpath and converted -Xrun agents
3852 if (Arguments::init_agents_at_startup()) {
3853 create_vm_init_agents();
3854 }
3855
3856 // Initialize Threads state
3857 _number_of_threads = 0;
3858 _number_of_non_daemon_threads = 0;
3859
3860 // Initialize global data structures and create system classes in heap
3861 vm_init_globals();
3862
3863 #if INCLUDE_JVMCI
3864 if (JVMCICounterSize > 0) {
3865 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
3866 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3867 } else {
3868 JavaThread::_jvmci_old_thread_counters = NULL;
3869 }
3870 #endif // INCLUDE_JVMCI
3871
3872 // Attach the main thread to this os thread
3873 JavaThread* main_thread = new JavaThread();
3874 main_thread->set_thread_state(_thread_in_vm);
3875 main_thread->initialize_thread_current();
3876 // must do this before set_active_handles
3877 main_thread->record_stack_base_and_size();
3878 main_thread->register_thread_stack_with_NMT();
3879 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3880
3881 if (!main_thread->set_as_starting_thread()) {
3882 vm_shutdown_during_initialization(
3883 "Failed necessary internal allocation. Out of swap space");
3884 main_thread->smr_delete();
3885 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3886 return JNI_ENOMEM;
3887 }
3888
3889 // Enable guard page *after* os::create_main_thread(), otherwise it would
3890 // crash Linux VM, see notes in os_linux.cpp.
3891 main_thread->create_stack_guard_pages();
3892
3893 // Initialize Java-Level synchronization subsystem
3894 ObjectMonitor::Initialize();
3895
3896 // Initialize global modules
3897 jint status = init_globals();
3898 if (status != JNI_OK) {
3899 main_thread->smr_delete();
3900 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3901 return status;
3902 }
3903
3904 JFR_ONLY(Jfr::on_create_vm_1();)
3905
3906 // Should be done after the heap is fully created
3907 main_thread->cache_global_variables();
3908
3909 HandleMark hm;
3910
3911 { MutexLocker mu(Threads_lock);
3912 Threads::add(main_thread);
3913 }
3914
3915 // Any JVMTI raw monitors entered in onload will transition into
3916 // real raw monitor. VM is setup enough here for raw monitor enter.
3917 JvmtiExport::transition_pending_onload_raw_monitors();
3918
3919 // Create the VMThread
3920 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3921
3922 VMThread::create();
3923 Thread* vmthread = VMThread::vm_thread();
3924
3925 if (!os::create_thread(vmthread, os::vm_thread)) {
3926 vm_exit_during_initialization("Cannot create VM thread. "
3927 "Out of system resources.");
3928 }
3929
3930 // Wait for the VM thread to become ready, and VMThread::run to initialize
3931 // Monitors can have spurious returns, must always check another state flag
3932 {
3933 MonitorLocker ml(Notify_lock);
3934 os::start_thread(vmthread);
3935 while (vmthread->active_handles() == NULL) {
3936 ml.wait();
3937 }
3938 }
3939 }
3940
3941 assert(Universe::is_fully_initialized(), "not initialized");
3942 if (VerifyDuringStartup) {
3943 // Make sure we're starting with a clean slate.
3944 VM_Verify verify_op;
3945 VMThread::execute(&verify_op);
3946 }
3947
3948 // We need this to update the java.vm.info property in case any flags used
3949 // to initially define it have been changed. This is needed for both CDS and
3950 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info
3951 // is initially computed. See Abstract_VM_Version::vm_info_string().
3952 // This update must happen before we initialize the java classes, but
3953 // after any initialization logic that might modify the flags.
3954 Arguments::update_vm_info_property(VM_Version::vm_info_string());
3955
3956 Thread* THREAD = Thread::current();
3957
3958 // Always call even when there are not JVMTI environments yet, since environments
3959 // may be attached late and JVMTI must track phases of VM execution
3960 JvmtiExport::enter_early_start_phase();
3961
3962 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3963 JvmtiExport::post_early_vm_start();
3964
3965 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3966
3967 quicken_jni_functions();
3968
3969 // No more stub generation allowed after that point.
3970 StubCodeDesc::freeze();
3971
3972 // Set flag that basic initialization has completed. Used by exceptions and various
3973 // debug stuff, that does not work until all basic classes have been initialized.
3974 set_init_completed();
3975
3976 LogConfiguration::post_initialize();
3977 Metaspace::post_initialize();
3978
3979 HOTSPOT_VM_INIT_END();
3980
3981 // record VM initialization completion time
3982 #if INCLUDE_MANAGEMENT
3983 Management::record_vm_init_completed();
3984 #endif // INCLUDE_MANAGEMENT
3985
3986 // Signal Dispatcher needs to be started before VMInit event is posted
3987 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3988
3989 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3990 if (!DisableAttachMechanism) {
3991 AttachListener::vm_start();
3992 if (StartAttachListener || AttachListener::init_at_startup()) {
3993 AttachListener::init();
3994 }
3995 }
3996
3997 // Launch -Xrun agents
3998 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3999 // back-end can launch with -Xdebug -Xrunjdwp.
4000 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
4001 create_vm_init_libraries();
4002 }
4003
4004 if (CleanChunkPoolAsync) {
4005 Chunk::start_chunk_pool_cleaner_task();
4006 }
4007
4008 // Start the service thread
4009 // The service thread enqueues JVMTI deferred events and does various hashtable
4010 // and other cleanups. Needs to start before the compilers start posting events.
4011 ServiceThread::initialize();
4012
4013 // initialize compiler(s)
4014 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
4015 #if INCLUDE_JVMCI
4016 bool force_JVMCI_intialization = false;
4017 if (EnableJVMCI) {
4018 // Initialize JVMCI eagerly when it is explicitly requested.
4019 // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
4020 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
4021
4022 if (!force_JVMCI_intialization) {
4023 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
4024 // compilations via JVMCI will not actually block until JVMCI is initialized.
4025 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
4026 }
4027 }
4028 #endif
4029 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
4030 // Postpone completion of compiler initialization to after JVMCI
4031 // is initialized to avoid timeouts of blocking compilations.
4032 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
4033 CompileBroker::compilation_init_phase2();
4034 }
4035 #endif
4036
4037 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
4038 // It is done after compilers are initialized, because otherwise compilations of
4039 // signature polymorphic MH intrinsics can be missed
4040 // (see SystemDictionary::find_method_handle_intrinsic).
4041 initialize_jsr292_core_classes(CHECK_JNI_ERR);
4042
4043 // This will initialize the module system. Only java.base classes can be
4044 // loaded until phase 2 completes
4045 call_initPhase2(CHECK_JNI_ERR);
4046
4047 JFR_ONLY(Jfr::on_create_vm_2();)
4048
4049 // Always call even when there are not JVMTI environments yet, since environments
4050 // may be attached late and JVMTI must track phases of VM execution
4051 JvmtiExport::enter_start_phase();
4052
4053 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
4054 JvmtiExport::post_vm_start();
4055
4056 // Final system initialization including security manager and system class loader
4057 call_initPhase3(CHECK_JNI_ERR);
4058
4059 // cache the system and platform class loaders
4060 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
4061
4062 #if INCLUDE_CDS
4063 // capture the module path info from the ModuleEntryTable
4064 ClassLoader::initialize_module_path(THREAD);
4065 #endif
4066
4067 #if INCLUDE_JVMCI
4068 if (force_JVMCI_intialization) {
4069 JVMCI::initialize_compiler(CHECK_JNI_ERR);
4070 CompileBroker::compilation_init_phase2();
4071 }
4072 #endif
4073
4074 // Always call even when there are not JVMTI environments yet, since environments
4075 // may be attached late and JVMTI must track phases of VM execution
4076 JvmtiExport::enter_live_phase();
4077
4078 // Make perfmemory accessible
4079 PerfMemory::set_accessible(true);
4080
4081 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
4082 JvmtiExport::post_vm_initialized();
4083
4084 JFR_ONLY(Jfr::on_create_vm_3();)
4085
4086 #if INCLUDE_MANAGEMENT
4087 Management::initialize(THREAD);
4088
4089 if (HAS_PENDING_EXCEPTION) {
4090 // management agent fails to start possibly due to
4091 // configuration problem and is responsible for printing
4092 // stack trace if appropriate. Simply exit VM.
4093 vm_exit(1);
4094 }
4095 #endif // INCLUDE_MANAGEMENT
4096
4097 if (MemProfiling) MemProfiler::engage();
4098 StatSampler::engage();
4099 if (CheckJNICalls) JniPeriodicChecker::engage();
4100
4101 BiasedLocking::init();
4102
4103 #if INCLUDE_RTM_OPT
4104 RTMLockingCounters::init();
4105 #endif
4106
4107 call_postVMInitHook(THREAD);
4108 // The Java side of PostVMInitHook.run must deal with all
4109 // exceptions and provide means of diagnosis.
4110 if (HAS_PENDING_EXCEPTION) {
4111 CLEAR_PENDING_EXCEPTION;
4112 }
4113
4114 {
4115 MutexLocker ml(PeriodicTask_lock);
4116 // Make sure the WatcherThread can be started by WatcherThread::start()
4117 // or by dynamic enrollment.
4118 WatcherThread::make_startable();
4119 // Start up the WatcherThread if there are any periodic tasks
4120 // NOTE: All PeriodicTasks should be registered by now. If they
4121 // aren't, late joiners might appear to start slowly (we might
4122 // take a while to process their first tick).
4123 if (PeriodicTask::num_tasks() > 0) {
4124 WatcherThread::start();
4125 }
4126 }
4127
4128 create_vm_timer.end();
4129 #ifdef ASSERT
4130 _vm_complete = true;
4131 #endif
4132
4133 if (DumpSharedSpaces) {
4134 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
4135 ShouldNotReachHere();
4136 }
4137
4138 return JNI_OK;
4139 }
4140
4141 // type for the Agent_OnLoad and JVM_OnLoad entry points
4142 extern "C" {
4143 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
4144 }
4145 // Find a command line agent library and return its entry point for
4146 // -agentlib: -agentpath: -Xrun
4147 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
4148 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
4149 const char *on_load_symbols[],
4150 size_t num_symbol_entries) {
4151 OnLoadEntry_t on_load_entry = NULL;
4152 void *library = NULL;
4153
4154 if (!agent->valid()) {
4155 char buffer[JVM_MAXPATHLEN];
4156 char ebuf[1024] = "";
4157 const char *name = agent->name();
4158 const char *msg = "Could not find agent library ";
4159
4160 // First check to see if agent is statically linked into executable
4161 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
4162 library = agent->os_lib();
4163 } else if (agent->is_absolute_path()) {
4164 library = os::dll_load(name, ebuf, sizeof ebuf);
4165 if (library == NULL) {
4166 const char *sub_msg = " in absolute path, with error: ";
4167 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4168 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4169 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4170 // If we can't find the agent, exit.
4171 vm_exit_during_initialization(buf, NULL);
4172 FREE_C_HEAP_ARRAY(char, buf);
4173 }
4174 } else {
4175 // Try to load the agent from the standard dll directory
4176 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4177 name)) {
4178 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4179 }
4180 if (library == NULL) { // Try the library path directory.
4181 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4182 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4183 }
4184 if (library == NULL) {
4185 const char *sub_msg = " on the library path, with error: ";
4186 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4187
4188 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4189 strlen(ebuf) + strlen(sub_msg2) + 1;
4190 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4191 if (!agent->is_instrument_lib()) {
4192 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4193 } else {
4194 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4195 }
4196 // If we can't find the agent, exit.
4197 vm_exit_during_initialization(buf, NULL);
4198 FREE_C_HEAP_ARRAY(char, buf);
4199 }
4200 }
4201 }
4202 agent->set_os_lib(library);
4203 agent->set_valid();
4204 }
4205
4206 // Find the OnLoad function.
4207 on_load_entry =
4208 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4209 false,
4210 on_load_symbols,
4211 num_symbol_entries));
4212 return on_load_entry;
4213 }
4214
4215 // Find the JVM_OnLoad entry point
4216 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4217 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4218 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4219 }
4220
4221 // Find the Agent_OnLoad entry point
4222 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4223 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4224 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4225 }
4226
4227 // For backwards compatibility with -Xrun
4228 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4229 // treated like -agentpath:
4230 // Must be called before agent libraries are created
4231 void Threads::convert_vm_init_libraries_to_agents() {
4232 AgentLibrary* agent;
4233 AgentLibrary* next;
4234
4235 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4236 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4237 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4238
4239 // If there is an JVM_OnLoad function it will get called later,
4240 // otherwise see if there is an Agent_OnLoad
4241 if (on_load_entry == NULL) {
4242 on_load_entry = lookup_agent_on_load(agent);
4243 if (on_load_entry != NULL) {
4244 // switch it to the agent list -- so that Agent_OnLoad will be called,
4245 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4246 Arguments::convert_library_to_agent(agent);
4247 } else {
4248 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4249 }
4250 }
4251 }
4252 }
4253
4254 // Create agents for -agentlib: -agentpath: and converted -Xrun
4255 // Invokes Agent_OnLoad
4256 // Called very early -- before JavaThreads exist
4257 void Threads::create_vm_init_agents() {
4258 extern struct JavaVM_ main_vm;
4259 AgentLibrary* agent;
4260
4261 JvmtiExport::enter_onload_phase();
4262
4263 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4264 // CDS dumping does not support native JVMTI agent.
4265 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
4266 if (Arguments::is_dumping_archive()) {
4267 if(!agent->is_instrument_lib()) {
4268 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
4269 } else if (!AllowArchivingWithJavaAgent) {
4270 vm_exit_during_cds_dumping(
4271 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
4272 }
4273 }
4274
4275 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4276
4277 if (on_load_entry != NULL) {
4278 // Invoke the Agent_OnLoad function
4279 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4280 if (err != JNI_OK) {
4281 vm_exit_during_initialization("agent library failed to init", agent->name());
4282 }
4283 } else {
4284 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4285 }
4286 }
4287
4288 JvmtiExport::enter_primordial_phase();
4289 }
4290
4291 extern "C" {
4292 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4293 }
4294
4295 void Threads::shutdown_vm_agents() {
4296 // Send any Agent_OnUnload notifications
4297 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4298 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4299 extern struct JavaVM_ main_vm;
4300 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4301
4302 // Find the Agent_OnUnload function.
4303 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4304 os::find_agent_function(agent,
4305 false,
4306 on_unload_symbols,
4307 num_symbol_entries));
4308
4309 // Invoke the Agent_OnUnload function
4310 if (unload_entry != NULL) {
4311 JavaThread* thread = JavaThread::current();
4312 ThreadToNativeFromVM ttn(thread);
4313 HandleMark hm(thread);
4314 (*unload_entry)(&main_vm);
4315 }
4316 }
4317 }
4318
4319 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4320 // Invokes JVM_OnLoad
4321 void Threads::create_vm_init_libraries() {
4322 extern struct JavaVM_ main_vm;
4323 AgentLibrary* agent;
4324
4325 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4326 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4327
4328 if (on_load_entry != NULL) {
4329 // Invoke the JVM_OnLoad function
4330 JavaThread* thread = JavaThread::current();
4331 ThreadToNativeFromVM ttn(thread);
4332 HandleMark hm(thread);
4333 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4334 if (err != JNI_OK) {
4335 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4336 }
4337 } else {
4338 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4339 }
4340 }
4341 }
4342
4343
4344 // Last thread running calls java.lang.Shutdown.shutdown()
4345 void JavaThread::invoke_shutdown_hooks() {
4346 HandleMark hm(this);
4347
4348 // We could get here with a pending exception, if so clear it now.
4349 if (this->has_pending_exception()) {
4350 this->clear_pending_exception();
4351 }
4352
4353 EXCEPTION_MARK;
4354 Klass* shutdown_klass =
4355 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4356 THREAD);
4357 if (shutdown_klass != NULL) {
4358 // SystemDictionary::resolve_or_null will return null if there was
4359 // an exception. If we cannot load the Shutdown class, just don't
4360 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4361 // won't be run. Note that if a shutdown hook was registered,
4362 // the Shutdown class would have already been loaded
4363 // (Runtime.addShutdownHook will load it).
4364 JavaValue result(T_VOID);
4365 JavaCalls::call_static(&result,
4366 shutdown_klass,
4367 vmSymbols::shutdown_name(),
4368 vmSymbols::void_method_signature(),
4369 THREAD);
4370 }
4371 CLEAR_PENDING_EXCEPTION;
4372 }
4373
4374 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4375 // the program falls off the end of main(). Another VM exit path is through
4376 // vm_exit() when the program calls System.exit() to return a value or when
4377 // there is a serious error in VM. The two shutdown paths are not exactly
4378 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4379 // and VM_Exit op at VM level.
4380 //
4381 // Shutdown sequence:
4382 // + Shutdown native memory tracking if it is on
4383 // + Wait until we are the last non-daemon thread to execute
4384 // <-- every thing is still working at this moment -->
4385 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4386 // shutdown hooks
4387 // + Call before_exit(), prepare for VM exit
4388 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4389 // currently the only user of this mechanism is File.deleteOnExit())
4390 // > stop StatSampler, watcher thread,
4391 // post thread end and vm death events to JVMTI,
4392 // stop signal thread
4393 // + Call JavaThread::exit(), it will:
4394 // > release JNI handle blocks, remove stack guard pages
4395 // > remove this thread from Threads list
4396 // <-- no more Java code from this thread after this point -->
4397 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4398 // the compiler threads at safepoint
4399 // <-- do not use anything that could get blocked by Safepoint -->
4400 // + Disable tracing at JNI/JVM barriers
4401 // + Set _vm_exited flag for threads that are still running native code
4402 // + Call exit_globals()
4403 // > deletes tty
4404 // > deletes PerfMemory resources
4405 // + Delete this thread
4406 // + Return to caller
4407
4408 bool Threads::destroy_vm() {
4409 JavaThread* thread = JavaThread::current();
4410
4411 #ifdef ASSERT
4412 _vm_complete = false;
4413 #endif
4414 // Wait until we are the last non-daemon thread to execute
4415 { MonitorLocker nu(Threads_lock);
4416 while (Threads::number_of_non_daemon_threads() > 1)
4417 // This wait should make safepoint checks, wait without a timeout,
4418 // and wait as a suspend-equivalent condition.
4419 nu.wait(0, Mutex::_as_suspend_equivalent_flag);
4420 }
4421
4422 EventShutdown e;
4423 if (e.should_commit()) {
4424 e.set_reason("No remaining non-daemon Java threads");
4425 e.commit();
4426 }
4427
4428 // Hang forever on exit if we are reporting an error.
4429 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4430 os::infinite_sleep();
4431 }
4432 os::wait_for_keypress_at_exit();
4433
4434 // run Java level shutdown hooks
4435 thread->invoke_shutdown_hooks();
4436
4437 before_exit(thread);
4438
4439 thread->exit(true);
4440
4441 // Stop VM thread.
4442 {
4443 // 4945125 The vm thread comes to a safepoint during exit.
4444 // GC vm_operations can get caught at the safepoint, and the
4445 // heap is unparseable if they are caught. Grab the Heap_lock
4446 // to prevent this. The GC vm_operations will not be able to
4447 // queue until after the vm thread is dead. After this point,
4448 // we'll never emerge out of the safepoint before the VM exits.
4449
4450 MutexLocker ml(Heap_lock, Mutex::_no_safepoint_check_flag);
4451
4452 VMThread::wait_for_vm_thread_exit();
4453 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4454 VMThread::destroy();
4455 }
4456
4457 // Now, all Java threads are gone except daemon threads. Daemon threads
4458 // running Java code or in VM are stopped by the Safepoint. However,
4459 // daemon threads executing native code are still running. But they
4460 // will be stopped at native=>Java/VM barriers. Note that we can't
4461 // simply kill or suspend them, as it is inherently deadlock-prone.
4462
4463 VM_Exit::set_vm_exited();
4464
4465 // Clean up ideal graph printers after the VMThread has started
4466 // the final safepoint which will block all the Compiler threads.
4467 // Note that this Thread has already logically exited so the
4468 // clean_up() function's use of a JavaThreadIteratorWithHandle
4469 // would be a problem except set_vm_exited() has remembered the
4470 // shutdown thread which is granted a policy exception.
4471 #if defined(COMPILER2) && !defined(PRODUCT)
4472 IdealGraphPrinter::clean_up();
4473 #endif
4474
4475 notify_vm_shutdown();
4476
4477 // exit_globals() will delete tty
4478 exit_globals();
4479
4480 // We are after VM_Exit::set_vm_exited() so we can't call
4481 // thread->smr_delete() or we will block on the Threads_lock.
4482 // Deleting the shutdown thread here is safe because another
4483 // JavaThread cannot have an active ThreadsListHandle for
4484 // this JavaThread.
4485 delete thread;
4486
4487 #if INCLUDE_JVMCI
4488 if (JVMCICounterSize > 0) {
4489 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4490 }
4491 #endif
4492
4493 LogConfiguration::finalize();
4494
4495 return true;
4496 }
4497
4498
4499 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4500 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4501 return is_supported_jni_version(version);
4502 }
4503
4504
4505 jboolean Threads::is_supported_jni_version(jint version) {
4506 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4507 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4508 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4509 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4510 if (version == JNI_VERSION_9) return JNI_TRUE;
4511 if (version == JNI_VERSION_10) return JNI_TRUE;
4512 return JNI_FALSE;
4513 }
4514
4515
4516 void Threads::add(JavaThread* p, bool force_daemon) {
4517 // The threads lock must be owned at this point
4518 assert(Threads_lock->owned_by_self(), "must have threads lock");
4519
4520 BarrierSet::barrier_set()->on_thread_attach(p);
4521
4522 // Once a JavaThread is added to the Threads list, smr_delete() has
4523 // to be used to delete it. Otherwise we can just delete it directly.
4524 p->set_on_thread_list();
4525
4526 _number_of_threads++;
4527 oop threadObj = p->threadObj();
4528 bool daemon = true;
4529 // Bootstrapping problem: threadObj can be null for initial
4530 // JavaThread (or for threads attached via JNI)
4531 if ((!force_daemon) && !is_daemon((threadObj))) {
4532 _number_of_non_daemon_threads++;
4533 daemon = false;
4534 }
4535
4536 ThreadService::add_thread(p, daemon);
4537
4538 // Maintain fast thread list
4539 ThreadsSMRSupport::add_thread(p);
4540
4541 // Possible GC point.
4542 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4543 }
4544
4545 void Threads::remove(JavaThread* p, bool is_daemon) {
4546
4547 // Reclaim the ObjectMonitors from the om_in_use_list and om_free_list of the moribund thread.
4548 ObjectSynchronizer::om_flush(p);
4549
4550 // Extra scope needed for Thread_lock, so we can check
4551 // that we do not remove thread without safepoint code notice
4552 { MonitorLocker ml(Threads_lock);
4553
4554 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4555
4556 // Maintain fast thread list
4557 ThreadsSMRSupport::remove_thread(p);
4558
4559 _number_of_threads--;
4560 if (!is_daemon) {
4561 _number_of_non_daemon_threads--;
4562
4563 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4564 // on destroy_vm will wake up.
4565 if (number_of_non_daemon_threads() == 1) {
4566 ml.notify_all();
4567 }
4568 }
4569 ThreadService::remove_thread(p, is_daemon);
4570
4571 // Make sure that safepoint code disregard this thread. This is needed since
4572 // the thread might mess around with locks after this point. This can cause it
4573 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4574 // of this thread since it is removed from the queue.
4575 p->set_terminated_value();
4576 } // unlock Threads_lock
4577
4578 // Since Events::log uses a lock, we grab it outside the Threads_lock
4579 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4580 }
4581
4582 // Operations on the Threads list for GC. These are not explicitly locked,
4583 // but the garbage collector must provide a safe context for them to run.
4584 // In particular, these things should never be called when the Threads_lock
4585 // is held by some other thread. (Note: the Safepoint abstraction also
4586 // uses the Threads_lock to guarantee this property. It also makes sure that
4587 // all threads gets blocked when exiting or starting).
4588
4589 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4590 ALL_JAVA_THREADS(p) {
4591 p->oops_do(f, cf);
4592 }
4593 VMThread::vm_thread()->oops_do(f, cf);
4594 }
4595
4596 void Threads::change_thread_claim_token() {
4597 if (++_thread_claim_token == 0) {
4598 // On overflow of the token counter, there is a risk of future
4599 // collisions between a new global token value and a stale token
4600 // for a thread, because not all iterations visit all threads.
4601 // (Though it's pretty much a theoretical concern for non-trivial
4602 // token counter sizes.) To deal with the possibility, reset all
4603 // the thread tokens to zero on global token overflow.
4604 struct ResetClaims : public ThreadClosure {
4605 virtual void do_thread(Thread* t) {
4606 t->claim_threads_do(false, 0);
4607 }
4608 } reset_claims;
4609 Threads::threads_do(&reset_claims);
4610 // On overflow, update the global token to non-zero, to
4611 // avoid the special "never claimed" initial thread value.
4612 _thread_claim_token = 1;
4613 }
4614 }
4615
4616 #ifdef ASSERT
4617 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
4618 const uintx token = t->threads_do_token();
4619 assert(token == expected,
4620 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
4621 UINTX_FORMAT, kind, p2i(t), token, expected);
4622 }
4623
4624 void Threads::assert_all_threads_claimed() {
4625 ALL_JAVA_THREADS(p) {
4626 assert_thread_claimed("Thread", p, _thread_claim_token);
4627 }
4628 assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token);
4629 }
4630 #endif // ASSERT
4631
4632 class ParallelOopsDoThreadClosure : public ThreadClosure {
4633 private:
4634 OopClosure* _f;
4635 CodeBlobClosure* _cf;
4636 public:
4637 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4638 void do_thread(Thread* t) {
4639 t->oops_do(_f, _cf);
4640 }
4641 };
4642
4643 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4644 ParallelOopsDoThreadClosure tc(f, cf);
4645 possibly_parallel_threads_do(is_par, &tc);
4646 }
4647
4648 void Threads::nmethods_do(CodeBlobClosure* cf) {
4649 ALL_JAVA_THREADS(p) {
4650 // This is used by the code cache sweeper to mark nmethods that are active
4651 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4652 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4653 if(!p->is_Code_cache_sweeper_thread()) {
4654 p->nmethods_do(cf);
4655 }
4656 }
4657 }
4658
4659 void Threads::metadata_do(MetadataClosure* f) {
4660 ALL_JAVA_THREADS(p) {
4661 p->metadata_do(f);
4662 }
4663 }
4664
4665 class ThreadHandlesClosure : public ThreadClosure {
4666 void (*_f)(Metadata*);
4667 public:
4668 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4669 virtual void do_thread(Thread* thread) {
4670 thread->metadata_handles_do(_f);
4671 }
4672 };
4673
4674 void Threads::metadata_handles_do(void f(Metadata*)) {
4675 // Only walk the Handles in Thread.
4676 ThreadHandlesClosure handles_closure(f);
4677 threads_do(&handles_closure);
4678 }
4679
4680 // Get count Java threads that are waiting to enter the specified monitor.
4681 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4682 int count,
4683 address monitor) {
4684 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4685
4686 int i = 0;
4687 DO_JAVA_THREADS(t_list, p) {
4688 if (!p->can_call_java()) continue;
4689
4690 address pending = (address)p->current_pending_monitor();
4691 if (pending == monitor) { // found a match
4692 if (i < count) result->append(p); // save the first count matches
4693 i++;
4694 }
4695 }
4696
4697 return result;
4698 }
4699
4700
4701 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4702 address owner) {
4703 // NULL owner means not locked so we can skip the search
4704 if (owner == NULL) return NULL;
4705
4706 DO_JAVA_THREADS(t_list, p) {
4707 // first, see if owner is the address of a Java thread
4708 if (owner == (address)p) return p;
4709 }
4710
4711 // Cannot assert on lack of success here since this function may be
4712 // used by code that is trying to report useful problem information
4713 // like deadlock detection.
4714 if (UseHeavyMonitors) return NULL;
4715
4716 // If we didn't find a matching Java thread and we didn't force use of
4717 // heavyweight monitors, then the owner is the stack address of the
4718 // Lock Word in the owning Java thread's stack.
4719 //
4720 JavaThread* the_owner = NULL;
4721 DO_JAVA_THREADS(t_list, q) {
4722 if (q->is_lock_owned(owner)) {
4723 the_owner = q;
4724 break;
4725 }
4726 }
4727
4728 // cannot assert on lack of success here; see above comment
4729 return the_owner;
4730 }
4731
4732 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4733 void Threads::print_on(outputStream* st, bool print_stacks,
4734 bool internal_format, bool print_concurrent_locks,
4735 bool print_extended_info) {
4736 char buf[32];
4737 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4738
4739 st->print_cr("Full thread dump %s (%s %s):",
4740 VM_Version::vm_name(),
4741 VM_Version::vm_release(),
4742 VM_Version::vm_info_string());
4743 st->cr();
4744
4745 #if INCLUDE_SERVICES
4746 // Dump concurrent locks
4747 ConcurrentLocksDump concurrent_locks;
4748 if (print_concurrent_locks) {
4749 concurrent_locks.dump_at_safepoint();
4750 }
4751 #endif // INCLUDE_SERVICES
4752
4753 ThreadsSMRSupport::print_info_on(st);
4754 st->cr();
4755
4756 ALL_JAVA_THREADS(p) {
4757 ResourceMark rm;
4758 p->print_on(st, print_extended_info);
4759 if (print_stacks) {
4760 if (internal_format) {
4761 p->trace_stack();
4762 } else {
4763 p->print_stack_on(st);
4764 }
4765 }
4766 st->cr();
4767 #if INCLUDE_SERVICES
4768 if (print_concurrent_locks) {
4769 concurrent_locks.print_locks_on(p, st);
4770 }
4771 #endif // INCLUDE_SERVICES
4772 }
4773
4774 VMThread::vm_thread()->print_on(st);
4775 st->cr();
4776 Universe::heap()->print_gc_threads_on(st);
4777 WatcherThread* wt = WatcherThread::watcher_thread();
4778 if (wt != NULL) {
4779 wt->print_on(st);
4780 st->cr();
4781 }
4782
4783 st->flush();
4784 }
4785
4786 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4787 int buflen, bool* found_current) {
4788 if (this_thread != NULL) {
4789 bool is_current = (current == this_thread);
4790 *found_current = *found_current || is_current;
4791 st->print("%s", is_current ? "=>" : " ");
4792
4793 st->print(PTR_FORMAT, p2i(this_thread));
4794 st->print(" ");
4795 this_thread->print_on_error(st, buf, buflen);
4796 st->cr();
4797 }
4798 }
4799
4800 class PrintOnErrorClosure : public ThreadClosure {
4801 outputStream* _st;
4802 Thread* _current;
4803 char* _buf;
4804 int _buflen;
4805 bool* _found_current;
4806 public:
4807 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4808 int buflen, bool* found_current) :
4809 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4810
4811 virtual void do_thread(Thread* thread) {
4812 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4813 }
4814 };
4815
4816 // Threads::print_on_error() is called by fatal error handler. It's possible
4817 // that VM is not at safepoint and/or current thread is inside signal handler.
4818 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4819 // memory (even in resource area), it might deadlock the error handler.
4820 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4821 int buflen) {
4822 ThreadsSMRSupport::print_info_on(st);
4823 st->cr();
4824
4825 bool found_current = false;
4826 st->print_cr("Java Threads: ( => current thread )");
4827 ALL_JAVA_THREADS(thread) {
4828 print_on_error(thread, st, current, buf, buflen, &found_current);
4829 }
4830 st->cr();
4831
4832 st->print_cr("Other Threads:");
4833 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4834 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4835
4836 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4837 Universe::heap()->gc_threads_do(&print_closure);
4838
4839 if (!found_current) {
4840 st->cr();
4841 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4842 current->print_on_error(st, buf, buflen);
4843 st->cr();
4844 }
4845 st->cr();
4846
4847 st->print_cr("Threads with active compile tasks:");
4848 print_threads_compiling(st, buf, buflen);
4849 }
4850
4851 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
4852 ALL_JAVA_THREADS(thread) {
4853 if (thread->is_Compiler_thread()) {
4854 CompilerThread* ct = (CompilerThread*) thread;
4855
4856 // Keep task in local variable for NULL check.
4857 // ct->_task might be set to NULL by concurring compiler thread
4858 // because it completed the compilation. The task is never freed,
4859 // though, just returned to a free list.
4860 CompileTask* task = ct->task();
4861 if (task != NULL) {
4862 thread->print_name_on_error(st, buf, buflen);
4863 st->print(" ");
4864 task->print(st, NULL, short_form, true);
4865 }
4866 }
4867 }
4868 }
4869
4870
4871 // Internal SpinLock and Mutex
4872 // Based on ParkEvent
4873
4874 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4875 //
4876 // We employ SpinLocks _only for low-contention, fixed-length
4877 // short-duration critical sections where we're concerned
4878 // about native mutex_t or HotSpot Mutex:: latency.
4879 // The mux construct provides a spin-then-block mutual exclusion
4880 // mechanism.
4881 //
4882 // Testing has shown that contention on the ListLock guarding gFreeList
4883 // is common. If we implement ListLock as a simple SpinLock it's common
4884 // for the JVM to devolve to yielding with little progress. This is true
4885 // despite the fact that the critical sections protected by ListLock are
4886 // extremely short.
4887 //
4888 // TODO-FIXME: ListLock should be of type SpinLock.
4889 // We should make this a 1st-class type, integrated into the lock
4890 // hierarchy as leaf-locks. Critically, the SpinLock structure
4891 // should have sufficient padding to avoid false-sharing and excessive
4892 // cache-coherency traffic.
4893
4894
4895 typedef volatile int SpinLockT;
4896
4897 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4898 if (Atomic::cmpxchg(adr, 0, 1) == 0) {
4899 return; // normal fast-path return
4900 }
4901
4902 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4903 int ctr = 0;
4904 int Yields = 0;
4905 for (;;) {
4906 while (*adr != 0) {
4907 ++ctr;
4908 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4909 if (Yields > 5) {
4910 os::naked_short_sleep(1);
4911 } else {
4912 os::naked_yield();
4913 ++Yields;
4914 }
4915 } else {
4916 SpinPause();
4917 }
4918 }
4919 if (Atomic::cmpxchg(adr, 0, 1) == 0) return;
4920 }
4921 }
4922
4923 void Thread::SpinRelease(volatile int * adr) {
4924 assert(*adr != 0, "invariant");
4925 OrderAccess::fence(); // guarantee at least release consistency.
4926 // Roach-motel semantics.
4927 // It's safe if subsequent LDs and STs float "up" into the critical section,
4928 // but prior LDs and STs within the critical section can't be allowed
4929 // to reorder or float past the ST that releases the lock.
4930 // Loads and stores in the critical section - which appear in program
4931 // order before the store that releases the lock - must also appear
4932 // before the store that releases the lock in memory visibility order.
4933 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4934 // the ST of 0 into the lock-word which releases the lock, so fence
4935 // more than covers this on all platforms.
4936 *adr = 0;
4937 }
4938
4939 // muxAcquire and muxRelease:
4940 //
4941 // * muxAcquire and muxRelease support a single-word lock-word construct.
4942 // The LSB of the word is set IFF the lock is held.
4943 // The remainder of the word points to the head of a singly-linked list
4944 // of threads blocked on the lock.
4945 //
4946 // * The current implementation of muxAcquire-muxRelease uses its own
4947 // dedicated Thread._MuxEvent instance. If we're interested in
4948 // minimizing the peak number of extant ParkEvent instances then
4949 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4950 // as certain invariants were satisfied. Specifically, care would need
4951 // to be taken with regards to consuming unpark() "permits".
4952 // A safe rule of thumb is that a thread would never call muxAcquire()
4953 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4954 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4955 // consume an unpark() permit intended for monitorenter, for instance.
4956 // One way around this would be to widen the restricted-range semaphore
4957 // implemented in park(). Another alternative would be to provide
4958 // multiple instances of the PlatformEvent() for each thread. One
4959 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4960 //
4961 // * Usage:
4962 // -- Only as leaf locks
4963 // -- for short-term locking only as muxAcquire does not perform
4964 // thread state transitions.
4965 //
4966 // Alternatives:
4967 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4968 // but with parking or spin-then-park instead of pure spinning.
4969 // * Use Taura-Oyama-Yonenzawa locks.
4970 // * It's possible to construct a 1-0 lock if we encode the lockword as
4971 // (List,LockByte). Acquire will CAS the full lockword while Release
4972 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4973 // acquiring threads use timers (ParkTimed) to detect and recover from
4974 // the stranding window. Thread/Node structures must be aligned on 256-byte
4975 // boundaries by using placement-new.
4976 // * Augment MCS with advisory back-link fields maintained with CAS().
4977 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4978 // The validity of the backlinks must be ratified before we trust the value.
4979 // If the backlinks are invalid the exiting thread must back-track through the
4980 // the forward links, which are always trustworthy.
4981 // * Add a successor indication. The LockWord is currently encoded as
4982 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4983 // to provide the usual futile-wakeup optimization.
4984 // See RTStt for details.
4985 //
4986
4987
4988 const intptr_t LOCKBIT = 1;
4989
4990 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4991 intptr_t w = Atomic::cmpxchg(Lock, (intptr_t)0, LOCKBIT);
4992 if (w == 0) return;
4993 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) {
4994 return;
4995 }
4996
4997 ParkEvent * const Self = Thread::current()->_MuxEvent;
4998 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4999 for (;;) {
5000 int its = (os::is_MP() ? 100 : 0) + 1;
5001
5002 // Optional spin phase: spin-then-park strategy
5003 while (--its >= 0) {
5004 w = *Lock;
5005 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) {
5006 return;
5007 }
5008 }
5009
5010 Self->reset();
5011 Self->OnList = intptr_t(Lock);
5012 // The following fence() isn't _strictly necessary as the subsequent
5013 // CAS() both serializes execution and ratifies the fetched *Lock value.
5014 OrderAccess::fence();
5015 for (;;) {
5016 w = *Lock;
5017 if ((w & LOCKBIT) == 0) {
5018 if (Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) {
5019 Self->OnList = 0; // hygiene - allows stronger asserts
5020 return;
5021 }
5022 continue; // Interference -- *Lock changed -- Just retry
5023 }
5024 assert(w & LOCKBIT, "invariant");
5025 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
5026 if (Atomic::cmpxchg(Lock, w, intptr_t(Self)|LOCKBIT) == w) break;
5027 }
5028
5029 while (Self->OnList != 0) {
5030 Self->park();
5031 }
5032 }
5033 }
5034
5035 // Release() must extract a successor from the list and then wake that thread.
5036 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
5037 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
5038 // Release() would :
5039 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
5040 // (B) Extract a successor from the private list "in-hand"
5041 // (C) attempt to CAS() the residual back into *Lock over null.
5042 // If there were any newly arrived threads and the CAS() would fail.
5043 // In that case Release() would detach the RATs, re-merge the list in-hand
5044 // with the RATs and repeat as needed. Alternately, Release() might
5045 // detach and extract a successor, but then pass the residual list to the wakee.
5046 // The wakee would be responsible for reattaching and remerging before it
5047 // competed for the lock.
5048 //
5049 // Both "pop" and DMR are immune from ABA corruption -- there can be
5050 // multiple concurrent pushers, but only one popper or detacher.
5051 // This implementation pops from the head of the list. This is unfair,
5052 // but tends to provide excellent throughput as hot threads remain hot.
5053 // (We wake recently run threads first).
5054 //
5055 // All paths through muxRelease() will execute a CAS.
5056 // Release consistency -- We depend on the CAS in muxRelease() to provide full
5057 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
5058 // executed within the critical section are complete and globally visible before the
5059 // store (CAS) to the lock-word that releases the lock becomes globally visible.
5060 void Thread::muxRelease(volatile intptr_t * Lock) {
5061 for (;;) {
5062 const intptr_t w = Atomic::cmpxchg(Lock, LOCKBIT, (intptr_t)0);
5063 assert(w & LOCKBIT, "invariant");
5064 if (w == LOCKBIT) return;
5065 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
5066 assert(List != NULL, "invariant");
5067 assert(List->OnList == intptr_t(Lock), "invariant");
5068 ParkEvent * const nxt = List->ListNext;
5069 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5070
5071 // The following CAS() releases the lock and pops the head element.
5072 // The CAS() also ratifies the previously fetched lock-word value.
5073 if (Atomic::cmpxchg(Lock, w, intptr_t(nxt)) != w) {
5074 continue;
5075 }
5076 List->OnList = 0;
5077 OrderAccess::fence();
5078 List->unpark();
5079 return;
5080 }
5081 }
5082
5083
5084 void Threads::verify() {
5085 ALL_JAVA_THREADS(p) {
5086 p->verify();
5087 }
5088 VMThread* thread = VMThread::vm_thread();
5089 if (thread != NULL) thread->verify();
5090 }