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