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