1 /*
2 * Copyright (c) 1997, 2018, 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 "classfile/classLoader.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/moduleEntry.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "classfile/vmSymbols.hpp"
32 #include "code/codeCache.hpp"
33 #include "code/scopeDesc.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "compiler/compileTask.hpp"
36 #include "gc/shared/barrierSet.hpp"
37 #include "gc/shared/gcId.hpp"
38 #include "gc/shared/gcLocker.inline.hpp"
39 #include "gc/shared/workgroup.hpp"
40 #include "interpreter/interpreter.hpp"
41 #include "interpreter/linkResolver.hpp"
42 #include "interpreter/oopMapCache.hpp"
43 #include "jfr/jfrEvents.hpp"
44 #include "jvmtifiles/jvmtiEnv.hpp"
45 #include "logging/log.hpp"
46 #include "logging/logConfiguration.hpp"
47 #include "logging/logStream.hpp"
48 #include "memory/allocation.inline.hpp"
49 #include "memory/metaspaceShared.hpp"
50 #include "memory/oopFactory.hpp"
51 #include "memory/resourceArea.hpp"
52 #include "memory/universe.hpp"
53 #include "oops/access.inline.hpp"
54 #include "oops/instanceKlass.hpp"
55 #include "oops/objArrayOop.hpp"
56 #include "oops/oop.inline.hpp"
57 #include "oops/symbol.hpp"
58 #include "oops/typeArrayOop.inline.hpp"
59 #include "oops/verifyOopClosure.hpp"
60 #include "prims/jvm_misc.hpp"
61 #include "prims/jvmtiExport.hpp"
62 #include "prims/jvmtiThreadState.hpp"
63 #include "runtime/arguments.hpp"
64 #include "runtime/atomic.hpp"
65 #include "runtime/biasedLocking.hpp"
66 #include "runtime/fieldDescriptor.inline.hpp"
67 #include "runtime/flags/jvmFlagConstraintList.hpp"
68 #include "runtime/flags/jvmFlagRangeList.hpp"
69 #include "runtime/flags/jvmFlagWriteableList.hpp"
70 #include "runtime/deoptimization.hpp"
71 #include "runtime/frame.inline.hpp"
72 #include "runtime/handshake.hpp"
73 #include "runtime/init.hpp"
74 #include "runtime/interfaceSupport.inline.hpp"
75 #include "runtime/java.hpp"
76 #include "runtime/javaCalls.hpp"
77 #include "runtime/jniHandles.inline.hpp"
78 #include "runtime/jniPeriodicChecker.hpp"
79 #include "runtime/memprofiler.hpp"
80 #include "runtime/mutexLocker.hpp"
81 #include "runtime/objectMonitor.hpp"
82 #include "runtime/orderAccess.hpp"
83 #include "runtime/osThread.hpp"
84 #include "runtime/prefetch.inline.hpp"
85 #include "runtime/safepoint.hpp"
86 #include "runtime/safepointMechanism.inline.hpp"
87 #include "runtime/safepointVerifiers.hpp"
88 #include "runtime/sharedRuntime.hpp"
89 #include "runtime/statSampler.hpp"
90 #include "runtime/stubRoutines.hpp"
91 #include "runtime/sweeper.hpp"
92 #include "runtime/task.hpp"
93 #include "runtime/thread.inline.hpp"
94 #include "runtime/threadCritical.hpp"
95 #include "runtime/threadSMR.inline.hpp"
96 #include "runtime/threadStatisticalInfo.hpp"
97 #include "runtime/timer.hpp"
98 #include "runtime/timerTrace.hpp"
99 #include "runtime/vframe.inline.hpp"
100 #include "runtime/vframeArray.hpp"
101 #include "runtime/vframe_hp.hpp"
102 #include "runtime/vmThread.hpp"
103 #include "runtime/vmOperations.hpp"
104 #include "runtime/vm_version.hpp"
105 #include "services/attachListener.hpp"
106 #include "services/management.hpp"
107 #include "services/memTracker.hpp"
108 #include "services/threadService.hpp"
109 #include "utilities/align.hpp"
110 #include "utilities/copy.hpp"
111 #include "utilities/defaultStream.hpp"
112 #include "utilities/dtrace.hpp"
113 #include "utilities/events.hpp"
114 #include "utilities/macros.hpp"
115 #include "utilities/preserveException.hpp"
116 #include "utilities/singleWriterSynchronizer.hpp"
117 #include "utilities/vmError.hpp"
118 #if INCLUDE_JVMCI
119 #include "jvmci/jvmciCompiler.hpp"
120 #include "jvmci/jvmciRuntime.hpp"
121 #include "logging/logHandle.hpp"
122 #endif
123 #ifdef COMPILER1
124 #include "c1/c1_Compiler.hpp"
125 #endif
126 #ifdef COMPILER2
127 #include "opto/c2compiler.hpp"
128 #include "opto/idealGraphPrinter.hpp"
129 #endif
130 #if INCLUDE_RTM_OPT
131 #include "runtime/rtmLocking.hpp"
132 #endif
133 #if INCLUDE_JFR
134 #include "jfr/jfr.hpp"
135 #endif
136
137 // Initialization after module runtime initialization
138 void universe_post_module_init(); // must happen after call_initPhase2
139
140 #ifdef DTRACE_ENABLED
141
142 // Only bother with this argument setup if dtrace is available
143
144 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
145 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
146
147 #define DTRACE_THREAD_PROBE(probe, javathread) \
148 { \
149 ResourceMark rm(this); \
150 int len = 0; \
151 const char* name = (javathread)->get_thread_name(); \
152 len = strlen(name); \
153 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
154 (char *) name, len, \
155 java_lang_Thread::thread_id((javathread)->threadObj()), \
156 (uintptr_t) (javathread)->osthread()->thread_id(), \
157 java_lang_Thread::is_daemon((javathread)->threadObj())); \
158 }
159
160 #else // ndef DTRACE_ENABLED
161
162 #define DTRACE_THREAD_PROBE(probe, javathread)
163
164 #endif // ndef DTRACE_ENABLED
165
166 #ifndef USE_LIBRARY_BASED_TLS_ONLY
167 // Current thread is maintained as a thread-local variable
168 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
169 #endif
170
171 // ======= Thread ========
172 // Support for forcing alignment of thread objects for biased locking
173 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
174 if (UseBiasedLocking) {
175 const int alignment = markOopDesc::biased_lock_alignment;
176 size_t aligned_size = size + (alignment - sizeof(intptr_t));
177 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
178 : AllocateHeap(aligned_size, flags, CURRENT_PC,
179 AllocFailStrategy::RETURN_NULL);
180 void* aligned_addr = align_up(real_malloc_addr, alignment);
181 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
182 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
183 "JavaThread alignment code overflowed allocated storage");
184 if (aligned_addr != real_malloc_addr) {
185 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
186 p2i(real_malloc_addr),
187 p2i(aligned_addr));
188 }
189 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
190 return aligned_addr;
191 } else {
192 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
193 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
194 }
195 }
196
197 void Thread::operator delete(void* p) {
198 if (UseBiasedLocking) {
199 FreeHeap(((Thread*) p)->_real_malloc_address);
200 } else {
201 FreeHeap(p);
202 }
203 }
204
205 void JavaThread::smr_delete() {
206 if (_on_thread_list) {
207 ThreadsSMRSupport::smr_delete(this);
208 } else {
209 delete this;
210 }
211 }
212
213 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
214 // JavaThread
215
216 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
217
218 Thread::Thread() {
219
220 DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
221
222 // stack and get_thread
223 set_stack_base(NULL);
224 set_stack_size(0);
225 set_self_raw_id(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 // This initial value ==> never claimed.
241 _oops_do_parity = 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 debug_only(_allow_allocation_count = 0;)
253 NOT_PRODUCT(_allow_safepoint_count = 0;)
254 NOT_PRODUCT(_skip_gcalot = false;)
255 _jvmti_env_iteration_count = 0;
256 set_allocated_bytes(0);
257 _vm_operation_started_count = 0;
258 _vm_operation_completed_count = 0;
259 _current_pending_monitor = NULL;
260 _current_pending_monitor_is_from_java = true;
261 _current_waiting_monitor = NULL;
262 _num_nested_signal = 0;
263 omFreeList = NULL;
264 omFreeCount = 0;
265 omFreeProvision = 32;
266 omInUseList = NULL;
267 omInUseCount = 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 _SleepEvent = ParkEvent::Allocate(this);
296 _MutexEvent = ParkEvent::Allocate(this);
297 _MuxEvent = ParkEvent::Allocate(this);
298
299 #ifdef CHECK_UNHANDLED_OOPS
300 if (CheckUnhandledOops) {
301 _unhandled_oops = new UnhandledOops(this);
302 }
303 #endif // CHECK_UNHANDLED_OOPS
304 #ifdef ASSERT
305 if (UseBiasedLocking) {
306 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
307 assert(this == _real_malloc_address ||
308 this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
309 "bug in forced alignment of thread objects");
310 }
311 #endif // ASSERT
312
313 // Notify the barrier set that a thread is being created. The initial
314 // thread is created before the barrier set is available. The call to
315 // BarrierSet::on_thread_create() for this thread is therefore deferred
316 // to BarrierSet::set_barrier_set().
317 BarrierSet* const barrier_set = BarrierSet::barrier_set();
318 if (barrier_set != NULL) {
319 barrier_set->on_thread_create(this);
320 } else {
321 // Only the main thread should be created before the barrier set
322 // and that happens just before Thread::current is set. No other thread
323 // can attach as the VM is not created yet, so they can't execute this code.
324 // If the main thread creates other threads before the barrier set that is an error.
325 assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
326 }
327 }
328
329 void Thread::initialize_thread_current() {
330 #ifndef USE_LIBRARY_BASED_TLS_ONLY
331 assert(_thr_current == NULL, "Thread::current already initialized");
332 _thr_current = this;
333 #endif
334 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
335 ThreadLocalStorage::set_thread(this);
336 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
337 }
338
339 void Thread::clear_thread_current() {
340 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
341 #ifndef USE_LIBRARY_BASED_TLS_ONLY
342 _thr_current = NULL;
343 #endif
344 ThreadLocalStorage::set_thread(NULL);
345 }
346
347 void Thread::record_stack_base_and_size() {
348 // Note: at this point, Thread object is not yet initialized. Do not rely on
349 // any members being initialized. Do not rely on Thread::current() being set.
350 // If possible, refrain from doing anything which may crash or assert since
351 // quite probably those crash dumps will be useless.
352 set_stack_base(os::current_stack_base());
353 set_stack_size(os::current_stack_size());
354
355 #ifdef SOLARIS
356 if (os::is_primordial_thread()) {
357 os::Solaris::correct_stack_boundaries_for_primordial_thread(this);
358 }
359 #endif
360
361 // Set stack limits after thread is initialized.
362 if (is_Java_thread()) {
363 ((JavaThread*) this)->set_stack_overflow_limit();
364 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
365 }
366 }
367
368 #if INCLUDE_NMT
369 void Thread::register_thread_stack_with_NMT() {
370 MemTracker::record_thread_stack(stack_end(), stack_size());
371 }
372 #endif // INCLUDE_NMT
373
374 void Thread::call_run() {
375 DEBUG_ONLY(_run_state = CALL_RUN;)
376
377 // At this point, Thread object should be fully initialized and
378 // Thread::current() should be set.
379
380 assert(Thread::current_or_null() != NULL, "current thread is unset");
381 assert(Thread::current_or_null() == this, "current thread is wrong");
382
383 // Perform common initialization actions
384
385 register_thread_stack_with_NMT();
386
387 JFR_ONLY(Jfr::on_thread_start(this);)
388
389 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
390 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
391 os::current_thread_id(), p2i(stack_base() - stack_size()),
392 p2i(stack_base()), stack_size()/1024);
393
394 // Perform <ChildClass> initialization actions
395 DEBUG_ONLY(_run_state = PRE_RUN;)
396 this->pre_run();
397
398 // Invoke <ChildClass>::run()
399 DEBUG_ONLY(_run_state = RUN;)
400 this->run();
401 // Returned from <ChildClass>::run(). Thread finished.
402
403 // Perform common tear-down actions
404
405 assert(Thread::current_or_null() != NULL, "current thread is unset");
406 assert(Thread::current_or_null() == this, "current thread is wrong");
407
408 // Perform <ChildClass> tear-down actions
409 DEBUG_ONLY(_run_state = POST_RUN;)
410 this->post_run();
411
412 // Note: at this point the thread object may already have deleted itself,
413 // so from here on do not dereference *this*. Not all thread types currently
414 // delete themselves when they terminate. But no thread should ever be deleted
415 // asynchronously with respect to its termination - that is what _run_state can
416 // be used to check.
417
418 assert(Thread::current_or_null() == NULL, "current thread still present");
419 }
420
421 Thread::~Thread() {
422
423 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
424 // get started due to errors etc. Any active thread should at least reach post_run
425 // before it is deleted (usually in post_run()).
426 assert(_run_state == PRE_CALL_RUN ||
427 _run_state == POST_RUN, "Active Thread deleted before post_run(): "
428 "_run_state=%d", (int)_run_state);
429
430 // Notify the barrier set that a thread is being destroyed. Note that a barrier
431 // set might not be available if we encountered errors during bootstrapping.
432 BarrierSet* const barrier_set = BarrierSet::barrier_set();
433 if (barrier_set != NULL) {
434 barrier_set->on_thread_destroy(this);
435 }
436
437 // stack_base can be NULL if the thread is never started or exited before
438 // record_stack_base_and_size called. Although, we would like to ensure
439 // that all started threads do call record_stack_base_and_size(), there is
440 // not proper way to enforce that.
441 #if INCLUDE_NMT
442 if (_stack_base != NULL) {
443 MemTracker::release_thread_stack(stack_end(), stack_size());
444 #ifdef ASSERT
445 set_stack_base(NULL);
446 #endif
447 }
448 #endif // INCLUDE_NMT
449
450 // deallocate data structures
451 delete resource_area();
452 // since the handle marks are using the handle area, we have to deallocated the root
453 // handle mark before deallocating the thread's handle area,
454 assert(last_handle_mark() != NULL, "check we have an element");
455 delete last_handle_mark();
456 assert(last_handle_mark() == NULL, "check we have reached the end");
457
458 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
459 // We NULL out the fields for good hygiene.
460 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
461 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
462 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
463 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
464
465 delete handle_area();
466 delete metadata_handles();
467
468 // SR_handler uses this as a termination indicator -
469 // needs to happen before os::free_thread()
470 delete _SR_lock;
471 _SR_lock = NULL;
472
473 // osthread() can be NULL, if creation of thread failed.
474 if (osthread() != NULL) os::free_thread(osthread());
475
476 // Clear Thread::current if thread is deleting itself and it has not
477 // already been done. This must be done before the memory is deallocated.
478 // Needed to ensure JNI correctly detects non-attached threads.
479 if (this == Thread::current_or_null()) {
480 Thread::clear_thread_current();
481 }
482
483 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
484 }
485
486 #ifdef ASSERT
487 // A JavaThread is considered "dangling" if it is not the current
488 // thread, has been added the Threads list, the system is not at a
489 // safepoint and the Thread is not "protected".
490 //
491 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
492 assert(!thread->is_Java_thread() || Thread::current() == thread ||
493 !((JavaThread *) thread)->on_thread_list() ||
494 SafepointSynchronize::is_at_safepoint() ||
495 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
496 "possibility of dangling Thread pointer");
497 }
498 #endif
499
500 ThreadPriority Thread::get_priority(const Thread* const thread) {
501 ThreadPriority priority;
502 // Can return an error!
503 (void)os::get_priority(thread, priority);
504 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
505 return priority;
506 }
507
508 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
509 debug_only(check_for_dangling_thread_pointer(thread);)
510 // Can return an error!
511 (void)os::set_priority(thread, priority);
512 }
513
514
515 void Thread::start(Thread* thread) {
516 // Start is different from resume in that its safety is guaranteed by context or
517 // being called from a Java method synchronized on the Thread object.
518 if (!DisableStartThread) {
519 if (thread->is_Java_thread()) {
520 // Initialize the thread state to RUNNABLE before starting this thread.
521 // Can not set it after the thread started because we do not know the
522 // exact thread state at that time. It could be in MONITOR_WAIT or
523 // in SLEEPING or some other state.
524 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
525 java_lang_Thread::RUNNABLE);
526 }
527 os::start_thread(thread);
528 }
529 }
530
531 // Enqueue a VM_Operation to do the job for us - sometime later
532 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
533 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
534 VMThread::execute(vm_stop);
535 }
536
537
538 // Check if an external suspend request has completed (or has been
539 // cancelled). Returns true if the thread is externally suspended and
540 // false otherwise.
541 //
542 // The bits parameter returns information about the code path through
543 // the routine. Useful for debugging:
544 //
545 // set in is_ext_suspend_completed():
546 // 0x00000001 - routine was entered
547 // 0x00000010 - routine return false at end
548 // 0x00000100 - thread exited (return false)
549 // 0x00000200 - suspend request cancelled (return false)
550 // 0x00000400 - thread suspended (return true)
551 // 0x00001000 - thread is in a suspend equivalent state (return true)
552 // 0x00002000 - thread is native and walkable (return true)
553 // 0x00004000 - thread is native_trans and walkable (needed retry)
554 //
555 // set in wait_for_ext_suspend_completion():
556 // 0x00010000 - routine was entered
557 // 0x00020000 - suspend request cancelled before loop (return false)
558 // 0x00040000 - thread suspended before loop (return true)
559 // 0x00080000 - suspend request cancelled in loop (return false)
560 // 0x00100000 - thread suspended in loop (return true)
561 // 0x00200000 - suspend not completed during retry loop (return false)
562
563 // Helper class for tracing suspend wait debug bits.
564 //
565 // 0x00000100 indicates that the target thread exited before it could
566 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
567 // 0x00080000 each indicate a cancelled suspend request so they don't
568 // count as wait failures either.
569 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
570
571 class TraceSuspendDebugBits : public StackObj {
572 private:
573 JavaThread * jt;
574 bool is_wait;
575 bool called_by_wait; // meaningful when !is_wait
576 uint32_t * bits;
577
578 public:
579 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
580 uint32_t *_bits) {
581 jt = _jt;
582 is_wait = _is_wait;
583 called_by_wait = _called_by_wait;
584 bits = _bits;
585 }
586
587 ~TraceSuspendDebugBits() {
588 if (!is_wait) {
589 #if 1
590 // By default, don't trace bits for is_ext_suspend_completed() calls.
591 // That trace is very chatty.
592 return;
593 #else
594 if (!called_by_wait) {
595 // If tracing for is_ext_suspend_completed() is enabled, then only
596 // trace calls to it from wait_for_ext_suspend_completion()
597 return;
598 }
599 #endif
600 }
601
602 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
603 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
604 MutexLocker ml(Threads_lock); // needed for get_thread_name()
605 ResourceMark rm;
606
607 tty->print_cr(
608 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
609 jt->get_thread_name(), *bits);
610
611 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
612 }
613 }
614 }
615 };
616 #undef DEBUG_FALSE_BITS
617
618
619 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
620 uint32_t *bits) {
621 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
622
623 bool did_trans_retry = false; // only do thread_in_native_trans retry once
624 bool do_trans_retry; // flag to force the retry
625
626 *bits |= 0x00000001;
627
628 do {
629 do_trans_retry = false;
630
631 if (is_exiting()) {
632 // Thread is in the process of exiting. This is always checked
633 // first to reduce the risk of dereferencing a freed JavaThread.
634 *bits |= 0x00000100;
635 return false;
636 }
637
638 if (!is_external_suspend()) {
639 // Suspend request is cancelled. This is always checked before
640 // is_ext_suspended() to reduce the risk of a rogue resume
641 // confusing the thread that made the suspend request.
642 *bits |= 0x00000200;
643 return false;
644 }
645
646 if (is_ext_suspended()) {
647 // thread is suspended
648 *bits |= 0x00000400;
649 return true;
650 }
651
652 // Now that we no longer do hard suspends of threads running
653 // native code, the target thread can be changing thread state
654 // while we are in this routine:
655 //
656 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
657 //
658 // We save a copy of the thread state as observed at this moment
659 // and make our decision about suspend completeness based on the
660 // copy. This closes the race where the thread state is seen as
661 // _thread_in_native_trans in the if-thread_blocked check, but is
662 // seen as _thread_blocked in if-thread_in_native_trans check.
663 JavaThreadState save_state = thread_state();
664
665 if (save_state == _thread_blocked && is_suspend_equivalent()) {
666 // If the thread's state is _thread_blocked and this blocking
667 // condition is known to be equivalent to a suspend, then we can
668 // consider the thread to be externally suspended. This means that
669 // the code that sets _thread_blocked has been modified to do
670 // self-suspension if the blocking condition releases. We also
671 // used to check for CONDVAR_WAIT here, but that is now covered by
672 // the _thread_blocked with self-suspension check.
673 //
674 // Return true since we wouldn't be here unless there was still an
675 // external suspend request.
676 *bits |= 0x00001000;
677 return true;
678 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
679 // Threads running native code will self-suspend on native==>VM/Java
680 // transitions. If its stack is walkable (should always be the case
681 // unless this function is called before the actual java_suspend()
682 // call), then the wait is done.
683 *bits |= 0x00002000;
684 return true;
685 } else if (!called_by_wait && !did_trans_retry &&
686 save_state == _thread_in_native_trans &&
687 frame_anchor()->walkable()) {
688 // The thread is transitioning from thread_in_native to another
689 // thread state. check_safepoint_and_suspend_for_native_trans()
690 // will force the thread to self-suspend. If it hasn't gotten
691 // there yet we may have caught the thread in-between the native
692 // code check above and the self-suspend. Lucky us. If we were
693 // called by wait_for_ext_suspend_completion(), then it
694 // will be doing the retries so we don't have to.
695 //
696 // Since we use the saved thread state in the if-statement above,
697 // there is a chance that the thread has already transitioned to
698 // _thread_blocked by the time we get here. In that case, we will
699 // make a single unnecessary pass through the logic below. This
700 // doesn't hurt anything since we still do the trans retry.
701
702 *bits |= 0x00004000;
703
704 // Once the thread leaves thread_in_native_trans for another
705 // thread state, we break out of this retry loop. We shouldn't
706 // need this flag to prevent us from getting back here, but
707 // sometimes paranoia is good.
708 did_trans_retry = true;
709
710 // We wait for the thread to transition to a more usable state.
711 for (int i = 1; i <= SuspendRetryCount; i++) {
712 // We used to do an "os::yield_all(i)" call here with the intention
713 // that yielding would increase on each retry. However, the parameter
714 // is ignored on Linux which means the yield didn't scale up. Waiting
715 // on the SR_lock below provides a much more predictable scale up for
716 // the delay. It also provides a simple/direct point to check for any
717 // safepoint requests from the VMThread
718
719 // temporarily drops SR_lock while doing wait with safepoint check
720 // (if we're a JavaThread - the WatcherThread can also call this)
721 // and increase delay with each retry
722 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
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 MutexLockerEx 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 MutexLocker ml(SR_lock());
795 // wait with safepoint check (if we're a JavaThread - the WatcherThread
796 // can also call this) and increase delay with each retry
797 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
798
799 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
800 delay, bits);
801
802 // It is possible for the external suspend request to be cancelled
803 // (by a resume) before the actual suspend operation is completed.
804 // Refresh our local copy to see if we still need to wait.
805 pending = is_external_suspend();
806 }
807
808 if (!pending) {
809 // A cancelled suspend request is the only false return from
810 // is_ext_suspend_completed() that keeps us from staying in the
811 // retry loop.
812 *bits |= 0x00080000;
813 return false;
814 }
815
816 if (is_suspended) {
817 *bits |= 0x00100000;
818 return true;
819 }
820 } // end retry loop
821
822 // thread did not suspend after all our retries
823 *bits |= 0x00200000;
824 return false;
825 }
826
827 // Called from API entry points which perform stack walking. If the
828 // associated JavaThread is the current thread, then wait_for_suspend
829 // is not used. Otherwise, it determines if we should wait for the
830 // "other" thread to complete external suspension. (NOTE: in future
831 // releases the suspension mechanism should be reimplemented so this
832 // is not necessary.)
833 //
834 bool
835 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
836 if (this != JavaThread::current()) {
837 // "other" threads require special handling.
838 if (wait_for_suspend) {
839 // We are allowed to wait for the external suspend to complete
840 // so give the other thread a chance to get suspended.
841 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
842 SuspendRetryDelay, bits)) {
843 // Didn't make it so let the caller know.
844 return false;
845 }
846 }
847 // We aren't allowed to wait for the external suspend to complete
848 // so if the other thread isn't externally suspended we need to
849 // let the caller know.
850 else if (!is_ext_suspend_completed_with_lock(bits)) {
851 return false;
852 }
853 }
854
855 return true;
856 }
857
858 #ifndef PRODUCT
859 void JavaThread::record_jump(address target, address instr, const char* file,
860 int line) {
861
862 // This should not need to be atomic as the only way for simultaneous
863 // updates is via interrupts. Even then this should be rare or non-existent
864 // and we don't care that much anyway.
865
866 int index = _jmp_ring_index;
867 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
868 _jmp_ring[index]._target = (intptr_t) target;
869 _jmp_ring[index]._instruction = (intptr_t) instr;
870 _jmp_ring[index]._file = file;
871 _jmp_ring[index]._line = line;
872 }
873 #endif // PRODUCT
874
875 void Thread::interrupt(Thread* thread) {
876 debug_only(check_for_dangling_thread_pointer(thread);)
877 os::interrupt(thread);
878 }
879
880 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
881 debug_only(check_for_dangling_thread_pointer(thread);)
882 // Note: If clear_interrupted==false, this simply fetches and
883 // returns the value of the field osthread()->interrupted().
884 return os::is_interrupted(thread, clear_interrupted);
885 }
886
887
888 // GC Support
889 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
890 int thread_parity = _oops_do_parity;
891 if (thread_parity != strong_roots_parity) {
892 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
893 if (res == thread_parity) {
894 return true;
895 } else {
896 guarantee(res == strong_roots_parity, "Or else what?");
897 return false;
898 }
899 }
900 return false;
901 }
902
903 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
904 active_handles()->oops_do(f);
905 // Do oop for ThreadShadow
906 f->do_oop((oop*)&_pending_exception);
907 handle_area()->oops_do(f);
908
909 // We scan thread local monitor lists here, and the remaining global
910 // monitors in ObjectSynchronizer::oops_do().
911 ObjectSynchronizer::thread_local_used_oops_do(this, f);
912 }
913
914 void Thread::metadata_handles_do(void f(Metadata*)) {
915 // Only walk the Handles in Thread.
916 if (metadata_handles() != NULL) {
917 for (int i = 0; i< metadata_handles()->length(); i++) {
918 f(metadata_handles()->at(i));
919 }
920 }
921 }
922
923 void Thread::print_on(outputStream* st, bool print_extended_info) const {
924 // get_priority assumes osthread initialized
925 if (osthread() != NULL) {
926 int os_prio;
927 if (os::get_native_priority(this, &os_prio) == OS_OK) {
928 st->print("os_prio=%d ", os_prio);
929 }
930
931 st->print("cpu=%.2fms ",
932 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
933 );
934 st->print("elapsed=%.2fs ",
935 _statistical_info.getElapsedTime() / 1000.0
936 );
937 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
938 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
939 st->print("allocated=" SIZE_FORMAT "%s ",
940 byte_size_in_proper_unit(allocated_bytes),
941 proper_unit_for_byte_size(allocated_bytes)
942 );
943 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
944 }
945
946 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
947 osthread()->print_on(st);
948 }
949 ThreadsSMRSupport::print_info_on(this, st);
950 st->print(" ");
951 debug_only(if (WizardMode) print_owned_locks_on(st);)
952 }
953
954 // Thread::print_on_error() is called by fatal error handler. Don't use
955 // any lock or allocate memory.
956 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
957 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
958
959 if (is_VM_thread()) { st->print("VMThread"); }
960 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
961 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
962 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
963 else { st->print("Thread"); }
964
965 if (is_Named_thread()) {
966 st->print(" \"%s\"", name());
967 }
968
969 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
970 p2i(stack_end()), p2i(stack_base()));
971
972 if (osthread()) {
973 st->print(" [id=%d]", osthread()->thread_id());
974 }
975
976 ThreadsSMRSupport::print_info_on(this, st);
977 }
978
979 void Thread::print_value_on(outputStream* st) const {
980 if (is_Named_thread()) {
981 st->print(" \"%s\" ", name());
982 }
983 st->print(INTPTR_FORMAT, p2i(this)); // print address
984 }
985
986 #ifdef ASSERT
987 void Thread::print_owned_locks_on(outputStream* st) const {
988 Monitor *cur = _owned_locks;
989 if (cur == NULL) {
990 st->print(" (no locks) ");
991 } else {
992 st->print_cr(" Locks owned:");
993 while (cur) {
994 cur->print_on(st);
995 cur = cur->next();
996 }
997 }
998 }
999
1000 static int ref_use_count = 0;
1001
1002 bool Thread::owns_locks_but_compiled_lock() const {
1003 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1004 if (cur != Compile_lock) return true;
1005 }
1006 return false;
1007 }
1008
1009
1010 #endif
1011
1012 #ifndef PRODUCT
1013
1014 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
1015 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
1016 // no locks which allow_vm_block's are held
1017 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
1018 // Check if current thread is allowed to block at a safepoint
1019 if (!(_allow_safepoint_count == 0)) {
1020 fatal("Possible safepoint reached by thread that does not allow it");
1021 }
1022 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
1023 fatal("LEAF method calling lock?");
1024 }
1025
1026 #ifdef ASSERT
1027 if (potential_vm_operation && is_Java_thread()
1028 && !Universe::is_bootstrapping()) {
1029 // Make sure we do not hold any locks that the VM thread also uses.
1030 // This could potentially lead to deadlocks
1031 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1032 // Threads_lock is special, since the safepoint synchronization will not start before this is
1033 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
1034 // since it is used to transfer control between JavaThreads and the VMThread
1035 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
1036 if ((cur->allow_vm_block() &&
1037 cur != Threads_lock &&
1038 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
1039 cur != VMOperationRequest_lock &&
1040 cur != VMOperationQueue_lock) ||
1041 cur->rank() == Mutex::special) {
1042 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
1043 }
1044 }
1045 }
1046
1047 if (GCALotAtAllSafepoints) {
1048 // We could enter a safepoint here and thus have a gc
1049 InterfaceSupport::check_gc_alot();
1050 }
1051 #endif
1052 }
1053 #endif
1054
1055 bool Thread::is_in_stack(address adr) const {
1056 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1057 address end = os::current_stack_pointer();
1058 // Allow non Java threads to call this without stack_base
1059 if (_stack_base == NULL) return true;
1060 if (stack_base() >= adr && adr >= end) return true;
1061
1062 return false;
1063 }
1064
1065 bool Thread::is_in_usable_stack(address adr) const {
1066 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1067 size_t usable_stack_size = _stack_size - stack_guard_size;
1068
1069 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1070 }
1071
1072
1073 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1074 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1075 // used for compilation in the future. If that change is made, the need for these methods
1076 // should be revisited, and they should be removed if possible.
1077
1078 bool Thread::is_lock_owned(address adr) const {
1079 return on_local_stack(adr);
1080 }
1081
1082 bool Thread::set_as_starting_thread() {
1083 assert(_starting_thread == NULL, "already initialized: "
1084 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
1085 // NOTE: this must be called inside the main thread.
1086 DEBUG_ONLY(_starting_thread = this;)
1087 return os::create_main_thread((JavaThread*)this);
1088 }
1089
1090 static void initialize_class(Symbol* class_name, TRAPS) {
1091 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1092 InstanceKlass::cast(klass)->initialize(CHECK);
1093 }
1094
1095
1096 // Creates the initial ThreadGroup
1097 static Handle create_initial_thread_group(TRAPS) {
1098 Handle system_instance = JavaCalls::construct_new_instance(
1099 SystemDictionary::ThreadGroup_klass(),
1100 vmSymbols::void_method_signature(),
1101 CHECK_NH);
1102 Universe::set_system_thread_group(system_instance());
1103
1104 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1105 Handle main_instance = JavaCalls::construct_new_instance(
1106 SystemDictionary::ThreadGroup_klass(),
1107 vmSymbols::threadgroup_string_void_signature(),
1108 system_instance,
1109 string,
1110 CHECK_NH);
1111 return main_instance;
1112 }
1113
1114 // Creates the initial Thread
1115 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1116 TRAPS) {
1117 InstanceKlass* ik = SystemDictionary::Thread_klass();
1118 assert(ik->is_initialized(), "must be");
1119 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1120
1121 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1122 // constructor calls Thread.current(), which must be set here for the
1123 // initial thread.
1124 java_lang_Thread::set_thread(thread_oop(), thread);
1125 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1126 thread->set_threadObj(thread_oop());
1127
1128 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1129
1130 JavaValue result(T_VOID);
1131 JavaCalls::call_special(&result, thread_oop,
1132 ik,
1133 vmSymbols::object_initializer_name(),
1134 vmSymbols::threadgroup_string_void_signature(),
1135 thread_group,
1136 string,
1137 CHECK_NULL);
1138 return thread_oop();
1139 }
1140
1141 char java_runtime_name[128] = "";
1142 char java_runtime_version[128] = "";
1143
1144 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1145 static const char* get_java_runtime_name(TRAPS) {
1146 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1147 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1148 fieldDescriptor fd;
1149 bool found = k != NULL &&
1150 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1151 vmSymbols::string_signature(), &fd);
1152 if (found) {
1153 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1154 if (name_oop == NULL) {
1155 return NULL;
1156 }
1157 const char* name = java_lang_String::as_utf8_string(name_oop,
1158 java_runtime_name,
1159 sizeof(java_runtime_name));
1160 return name;
1161 } else {
1162 return NULL;
1163 }
1164 }
1165
1166 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1167 static const char* get_java_runtime_version(TRAPS) {
1168 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1169 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1170 fieldDescriptor fd;
1171 bool found = k != NULL &&
1172 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1173 vmSymbols::string_signature(), &fd);
1174 if (found) {
1175 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1176 if (name_oop == NULL) {
1177 return NULL;
1178 }
1179 const char* name = java_lang_String::as_utf8_string(name_oop,
1180 java_runtime_version,
1181 sizeof(java_runtime_version));
1182 return name;
1183 } else {
1184 return NULL;
1185 }
1186 }
1187
1188 // General purpose hook into Java code, run once when the VM is initialized.
1189 // The Java library method itself may be changed independently from the VM.
1190 static void call_postVMInitHook(TRAPS) {
1191 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1192 if (klass != NULL) {
1193 JavaValue result(T_VOID);
1194 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1195 vmSymbols::void_method_signature(),
1196 CHECK);
1197 }
1198 }
1199
1200 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1201 bool daemon, TRAPS) {
1202 assert(thread_group.not_null(), "thread group should be specified");
1203 assert(threadObj() == NULL, "should only create Java thread object once");
1204
1205 InstanceKlass* ik = SystemDictionary::Thread_klass();
1206 assert(ik->is_initialized(), "must be");
1207 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1208
1209 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1210 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1211 // constructor calls Thread.current(), which must be set here.
1212 java_lang_Thread::set_thread(thread_oop(), this);
1213 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1214 set_threadObj(thread_oop());
1215
1216 JavaValue result(T_VOID);
1217 if (thread_name != NULL) {
1218 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1219 // Thread gets assigned specified name and null target
1220 JavaCalls::call_special(&result,
1221 thread_oop,
1222 ik,
1223 vmSymbols::object_initializer_name(),
1224 vmSymbols::threadgroup_string_void_signature(),
1225 thread_group,
1226 name,
1227 THREAD);
1228 } else {
1229 // Thread gets assigned name "Thread-nnn" and null target
1230 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1231 JavaCalls::call_special(&result,
1232 thread_oop,
1233 ik,
1234 vmSymbols::object_initializer_name(),
1235 vmSymbols::threadgroup_runnable_void_signature(),
1236 thread_group,
1237 Handle(),
1238 THREAD);
1239 }
1240
1241
1242 if (daemon) {
1243 java_lang_Thread::set_daemon(thread_oop());
1244 }
1245
1246 if (HAS_PENDING_EXCEPTION) {
1247 return;
1248 }
1249
1250 Klass* group = SystemDictionary::ThreadGroup_klass();
1251 Handle threadObj(THREAD, this->threadObj());
1252
1253 JavaCalls::call_special(&result,
1254 thread_group,
1255 group,
1256 vmSymbols::add_method_name(),
1257 vmSymbols::thread_void_signature(),
1258 threadObj, // Arg 1
1259 THREAD);
1260 }
1261
1262 // List of all NonJavaThreads and safe iteration over that list.
1263
1264 class NonJavaThread::List {
1265 public:
1266 NonJavaThread* volatile _head;
1267 SingleWriterSynchronizer _protect;
1268
1269 List() : _head(NULL), _protect() {}
1270 };
1271
1272 NonJavaThread::List NonJavaThread::_the_list;
1273
1274 NonJavaThread::Iterator::Iterator() :
1275 _protect_enter(_the_list._protect.enter()),
1276 _current(OrderAccess::load_acquire(&_the_list._head))
1277 {}
1278
1279 NonJavaThread::Iterator::~Iterator() {
1280 _the_list._protect.exit(_protect_enter);
1281 }
1282
1283 void NonJavaThread::Iterator::step() {
1284 assert(!end(), "precondition");
1285 _current = OrderAccess::load_acquire(&_current->_next);
1286 }
1287
1288 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) {
1289 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!");
1290 }
1291
1292 NonJavaThread::~NonJavaThread() { }
1293
1294 void NonJavaThread::add_to_the_list() {
1295 MutexLockerEx lock(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1296 _next = _the_list._head;
1297 OrderAccess::release_store(&_the_list._head, this);
1298 }
1299
1300 void NonJavaThread::remove_from_the_list() {
1301 MutexLockerEx lock(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1302 NonJavaThread* volatile* p = &_the_list._head;
1303 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) {
1304 if (t == this) {
1305 *p = this->_next;
1306 // Wait for any in-progress iterators. Concurrent synchronize is
1307 // not allowed, so do it while holding the list lock.
1308 _the_list._protect.synchronize();
1309 break;
1310 }
1311 }
1312 }
1313
1314 void NonJavaThread::pre_run() {
1315 assert(BarrierSet::barrier_set() != NULL, "invariant");
1316 add_to_the_list();
1317
1318 // This is slightly odd in that NamedThread is a subclass, but
1319 // in fact name() is defined in Thread
1320 assert(this->name() != NULL, "thread name was not set before it was started");
1321 this->set_native_thread_name(this->name());
1322 }
1323
1324 void NonJavaThread::post_run() {
1325 JFR_ONLY(Jfr::on_thread_exit(this);)
1326 remove_from_the_list();
1327 // Ensure thread-local-storage is cleared before termination.
1328 Thread::clear_thread_current();
1329 }
1330
1331 // NamedThread -- non-JavaThread subclasses with multiple
1332 // uniquely named instances should derive from this.
1333 NamedThread::NamedThread() :
1334 NonJavaThread(),
1335 _name(NULL),
1336 _processed_thread(NULL),
1337 _gc_id(GCId::undefined())
1338 {}
1339
1340 NamedThread::~NamedThread() {
1341 if (_name != NULL) {
1342 FREE_C_HEAP_ARRAY(char, _name);
1343 _name = NULL;
1344 }
1345 }
1346
1347 void NamedThread::set_name(const char* format, ...) {
1348 guarantee(_name == NULL, "Only get to set name once.");
1349 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1350 guarantee(_name != NULL, "alloc failure");
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 MutexLockerEx 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 = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1416 remaining);
1417 jlong now = os::javaTimeNanos();
1418
1419 if (remaining == 0) {
1420 // if we didn't have any tasks we could have waited for a long time
1421 // consider the time_slept zero and reset time_before_loop
1422 time_slept = 0;
1423 time_before_loop = now;
1424 } else {
1425 // need to recalculate since we might have new tasks in _tasks
1426 time_slept = (int) ((now - time_before_loop) / 1000000);
1427 }
1428
1429 // Change to task list or spurious wakeup of some kind
1430 if (timedout || _should_terminate) {
1431 break;
1432 }
1433
1434 remaining = PeriodicTask::time_to_wait();
1435 if (remaining == 0) {
1436 // Last task was just disenrolled so loop around and wait until
1437 // another task gets enrolled
1438 continue;
1439 }
1440
1441 remaining -= time_slept;
1442 if (remaining <= 0) {
1443 break;
1444 }
1445 }
1446
1447 return time_slept;
1448 }
1449
1450 void WatcherThread::run() {
1451 assert(this == watcher_thread(), "just checking");
1452
1453 this->set_active_handles(JNIHandleBlock::allocate_block());
1454 while (true) {
1455 assert(watcher_thread() == Thread::current(), "thread consistency check");
1456 assert(watcher_thread() == this, "thread consistency check");
1457
1458 // Calculate how long it'll be until the next PeriodicTask work
1459 // should be done, and sleep that amount of time.
1460 int time_waited = sleep();
1461
1462 if (VMError::is_error_reported()) {
1463 // A fatal error has happened, the error handler(VMError::report_and_die)
1464 // should abort JVM after creating an error log file. However in some
1465 // rare cases, the error handler itself might deadlock. Here periodically
1466 // check for error reporting timeouts, and if it happens, just proceed to
1467 // abort the VM.
1468
1469 // This code is in WatcherThread because WatcherThread wakes up
1470 // periodically so the fatal error handler doesn't need to do anything;
1471 // also because the WatcherThread is less likely to crash than other
1472 // threads.
1473
1474 for (;;) {
1475 // Note: we use naked sleep in this loop because we want to avoid using
1476 // any kind of VM infrastructure which may be broken at this point.
1477 if (VMError::check_timeout()) {
1478 // We hit error reporting timeout. Error reporting was interrupted and
1479 // will be wrapping things up now (closing files etc). Give it some more
1480 // time, then quit the VM.
1481 os::naked_short_sleep(200);
1482 // Print a message to stderr.
1483 fdStream err(defaultStream::output_fd());
1484 err.print_raw_cr("# [ timer expired, abort... ]");
1485 // skip atexit/vm_exit/vm_abort hooks
1486 os::die();
1487 }
1488
1489 // Wait a second, then recheck for timeout.
1490 os::naked_short_sleep(999);
1491 }
1492 }
1493
1494 if (_should_terminate) {
1495 // check for termination before posting the next tick
1496 break;
1497 }
1498
1499 PeriodicTask::real_time_tick(time_waited);
1500 }
1501
1502 // Signal that it is terminated
1503 {
1504 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1505 _watcher_thread = NULL;
1506 Terminator_lock->notify();
1507 }
1508 }
1509
1510 void WatcherThread::start() {
1511 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1512
1513 if (watcher_thread() == NULL && _startable) {
1514 _should_terminate = false;
1515 // Create the single instance of WatcherThread
1516 new WatcherThread();
1517 }
1518 }
1519
1520 void WatcherThread::make_startable() {
1521 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1522 _startable = true;
1523 }
1524
1525 void WatcherThread::stop() {
1526 {
1527 // Follow normal safepoint aware lock enter protocol since the
1528 // WatcherThread is stopped by another JavaThread.
1529 MutexLocker ml(PeriodicTask_lock);
1530 _should_terminate = true;
1531
1532 WatcherThread* watcher = watcher_thread();
1533 if (watcher != NULL) {
1534 // unpark the WatcherThread so it can see that it should terminate
1535 watcher->unpark();
1536 }
1537 }
1538
1539 MutexLocker mu(Terminator_lock);
1540
1541 while (watcher_thread() != NULL) {
1542 // This wait should make safepoint checks, wait without a timeout,
1543 // and wait as a suspend-equivalent condition.
1544 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1545 Mutex::_as_suspend_equivalent_flag);
1546 }
1547 }
1548
1549 void WatcherThread::unpark() {
1550 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1551 PeriodicTask_lock->notify();
1552 }
1553
1554 void WatcherThread::print_on(outputStream* st) const {
1555 st->print("\"%s\" ", name());
1556 Thread::print_on(st);
1557 st->cr();
1558 }
1559
1560 // ======= JavaThread ========
1561
1562 #if INCLUDE_JVMCI
1563
1564 jlong* JavaThread::_jvmci_old_thread_counters;
1565
1566 bool jvmci_counters_include(JavaThread* thread) {
1567 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1568 }
1569
1570 void JavaThread::collect_counters(typeArrayOop array) {
1571 if (JVMCICounterSize > 0) {
1572 JavaThreadIteratorWithHandle jtiwh;
1573 for (int i = 0; i < array->length(); i++) {
1574 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1575 }
1576 for (; JavaThread *tp = jtiwh.next(); ) {
1577 if (jvmci_counters_include(tp)) {
1578 for (int i = 0; i < array->length(); i++) {
1579 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1580 }
1581 }
1582 }
1583 }
1584 }
1585
1586 #endif // INCLUDE_JVMCI
1587
1588 // A JavaThread is a normal Java thread
1589
1590 void JavaThread::initialize() {
1591 // Initialize fields
1592
1593 set_saved_exception_pc(NULL);
1594 set_threadObj(NULL);
1595 _anchor.clear();
1596 set_entry_point(NULL);
1597 set_jni_functions(jni_functions());
1598 set_callee_target(NULL);
1599 set_vm_result(NULL);
1600 set_vm_result_2(NULL);
1601 set_vframe_array_head(NULL);
1602 set_vframe_array_last(NULL);
1603 set_deferred_locals(NULL);
1604 set_deopt_mark(NULL);
1605 set_deopt_compiled_method(NULL);
1606 clear_must_deopt_id();
1607 set_monitor_chunks(NULL);
1608 set_next(NULL);
1609 _on_thread_list = false;
1610 set_thread_state(_thread_new);
1611 _terminated = _not_terminated;
1612 _array_for_gc = NULL;
1613 _suspend_equivalent = false;
1614 _in_deopt_handler = 0;
1615 _doing_unsafe_access = false;
1616 _stack_guard_state = stack_guard_unused;
1617 #if INCLUDE_JVMCI
1618 _pending_monitorenter = false;
1619 _pending_deoptimization = -1;
1620 _pending_failed_speculation = 0;
1621 _pending_transfer_to_interpreter = false;
1622 _adjusting_comp_level = false;
1623 _in_retryable_allocation = false;
1624 _jvmci._alternate_call_target = NULL;
1625 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1626 if (JVMCICounterSize > 0) {
1627 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1628 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1629 } else {
1630 _jvmci_counters = NULL;
1631 }
1632 #endif // INCLUDE_JVMCI
1633 _reserved_stack_activation = NULL; // stack base not known yet
1634 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1635 _exception_pc = 0;
1636 _exception_handler_pc = 0;
1637 _is_method_handle_return = 0;
1638 _jvmti_thread_state= NULL;
1639 _should_post_on_exceptions_flag = JNI_FALSE;
1640 _interp_only_mode = 0;
1641 _special_runtime_exit_condition = _no_async_condition;
1642 _pending_async_exception = NULL;
1643 _thread_stat = NULL;
1644 _thread_stat = new ThreadStatistics();
1645 _blocked_on_compilation = false;
1646 _jni_active_critical = 0;
1647 _pending_jni_exception_check_fn = NULL;
1648 _do_not_unlock_if_synchronized = false;
1649 _cached_monitor_info = NULL;
1650 _parker = Parker::Allocate(this);
1651
1652 #ifndef PRODUCT
1653 _jmp_ring_index = 0;
1654 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1655 record_jump(NULL, NULL, NULL, 0);
1656 }
1657 #endif // PRODUCT
1658
1659 // Setup safepoint state info for this thread
1660 ThreadSafepointState::create(this);
1661
1662 debug_only(_java_call_counter = 0);
1663
1664 // JVMTI PopFrame support
1665 _popframe_condition = popframe_inactive;
1666 _popframe_preserved_args = NULL;
1667 _popframe_preserved_args_size = 0;
1668 _frames_to_pop_failed_realloc = 0;
1669
1670 if (SafepointMechanism::uses_thread_local_poll()) {
1671 SafepointMechanism::initialize_header(this);
1672 }
1673
1674 pd_initialize();
1675 }
1676
1677 JavaThread::JavaThread(bool is_attaching_via_jni) :
1678 Thread() {
1679 initialize();
1680 if (is_attaching_via_jni) {
1681 _jni_attach_state = _attaching_via_jni;
1682 } else {
1683 _jni_attach_state = _not_attaching_via_jni;
1684 }
1685 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1686 }
1687
1688 bool JavaThread::reguard_stack(address cur_sp) {
1689 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1690 && _stack_guard_state != stack_guard_reserved_disabled) {
1691 return true; // Stack already guarded or guard pages not needed.
1692 }
1693
1694 if (register_stack_overflow()) {
1695 // For those architectures which have separate register and
1696 // memory stacks, we must check the register stack to see if
1697 // it has overflowed.
1698 return false;
1699 }
1700
1701 // Java code never executes within the yellow zone: the latter is only
1702 // there to provoke an exception during stack banging. If java code
1703 // is executing there, either StackShadowPages should be larger, or
1704 // some exception code in c1, c2 or the interpreter isn't unwinding
1705 // when it should.
1706 guarantee(cur_sp > stack_reserved_zone_base(),
1707 "not enough space to reguard - increase StackShadowPages");
1708 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1709 enable_stack_yellow_reserved_zone();
1710 if (reserved_stack_activation() != stack_base()) {
1711 set_reserved_stack_activation(stack_base());
1712 }
1713 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1714 set_reserved_stack_activation(stack_base());
1715 enable_stack_reserved_zone();
1716 }
1717 return true;
1718 }
1719
1720 bool JavaThread::reguard_stack(void) {
1721 return reguard_stack(os::current_stack_pointer());
1722 }
1723
1724
1725 void JavaThread::block_if_vm_exited() {
1726 if (_terminated == _vm_exited) {
1727 // _vm_exited is set at safepoint, and Threads_lock is never released
1728 // we will block here forever
1729 Threads_lock->lock_without_safepoint_check();
1730 ShouldNotReachHere();
1731 }
1732 }
1733
1734
1735 // Remove this ifdef when C1 is ported to the compiler interface.
1736 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1737 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1738
1739 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1740 Thread() {
1741 initialize();
1742 _jni_attach_state = _not_attaching_via_jni;
1743 set_entry_point(entry_point);
1744 // Create the native thread itself.
1745 // %note runtime_23
1746 os::ThreadType thr_type = os::java_thread;
1747 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1748 os::java_thread;
1749 os::create_thread(this, thr_type, stack_sz);
1750 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1751 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1752 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1753 // the exception consists of creating the exception object & initializing it, initialization
1754 // will leave the VM via a JavaCall and then all locks must be unlocked).
1755 //
1756 // The thread is still suspended when we reach here. Thread must be explicit started
1757 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1758 // by calling Threads:add. The reason why this is not done here, is because the thread
1759 // object must be fully initialized (take a look at JVM_Start)
1760 }
1761
1762 JavaThread::~JavaThread() {
1763
1764 // JSR166 -- return the parker to the free list
1765 Parker::Release(_parker);
1766 _parker = NULL;
1767
1768 // Free any remaining previous UnrollBlock
1769 vframeArray* old_array = vframe_array_last();
1770
1771 if (old_array != NULL) {
1772 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1773 old_array->set_unroll_block(NULL);
1774 delete old_info;
1775 delete old_array;
1776 }
1777
1778 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1779 if (deferred != NULL) {
1780 // This can only happen if thread is destroyed before deoptimization occurs.
1781 assert(deferred->length() != 0, "empty array!");
1782 do {
1783 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1784 deferred->remove_at(0);
1785 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1786 delete dlv;
1787 } while (deferred->length() != 0);
1788 delete deferred;
1789 }
1790
1791 // All Java related clean up happens in exit
1792 ThreadSafepointState::destroy(this);
1793 if (_thread_stat != NULL) delete _thread_stat;
1794
1795 #if INCLUDE_JVMCI
1796 if (JVMCICounterSize > 0) {
1797 if (jvmci_counters_include(this)) {
1798 for (int i = 0; i < JVMCICounterSize; i++) {
1799 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1800 }
1801 }
1802 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1803 }
1804 #endif // INCLUDE_JVMCI
1805 }
1806
1807
1808 // First JavaThread specific code executed by a new Java thread.
1809 void JavaThread::pre_run() {
1810 // empty - see comments in run()
1811 }
1812
1813 // The main routine called by a new Java thread. This isn't overridden
1814 // by subclasses, instead different subclasses define a different "entry_point"
1815 // which defines the actual logic for that kind of thread.
1816 void JavaThread::run() {
1817 // initialize thread-local alloc buffer related fields
1818 this->initialize_tlab();
1819
1820 // Used to test validity of stack trace backs.
1821 // This can't be moved into pre_run() else we invalidate
1822 // the requirement that thread_main_inner is lower on
1823 // the stack. Consequently all the initialization logic
1824 // stays here in run() rather than pre_run().
1825 this->record_base_of_stack_pointer();
1826
1827 this->create_stack_guard_pages();
1828
1829 this->cache_global_variables();
1830
1831 // Thread is now sufficiently initialized to be handled by the safepoint code as being
1832 // in the VM. Change thread state from _thread_new to _thread_in_vm
1833 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1834
1835 assert(JavaThread::current() == this, "sanity check");
1836 assert(!Thread::current()->owns_locks(), "sanity check");
1837
1838 DTRACE_THREAD_PROBE(start, this);
1839
1840 // This operation might block. We call that after all safepoint checks for a new thread has
1841 // been completed.
1842 this->set_active_handles(JNIHandleBlock::allocate_block());
1843
1844 if (JvmtiExport::should_post_thread_life()) {
1845 JvmtiExport::post_thread_start(this);
1846
1847 }
1848
1849 // We call another function to do the rest so we are sure that the stack addresses used
1850 // from there will be lower than the stack base just computed.
1851 thread_main_inner();
1852 }
1853
1854 void JavaThread::thread_main_inner() {
1855 assert(JavaThread::current() == this, "sanity check");
1856 assert(this->threadObj() != NULL, "just checking");
1857
1858 // Execute thread entry point unless this thread has a pending exception
1859 // or has been stopped before starting.
1860 // Note: Due to JVM_StopThread we can have pending exceptions already!
1861 if (!this->has_pending_exception() &&
1862 !java_lang_Thread::is_stillborn(this->threadObj())) {
1863 {
1864 ResourceMark rm(this);
1865 this->set_native_thread_name(this->get_thread_name());
1866 }
1867 HandleMark hm(this);
1868 this->entry_point()(this, this);
1869 }
1870
1871 DTRACE_THREAD_PROBE(stop, this);
1872
1873 // Cleanup is handled in post_run()
1874 }
1875
1876 // Shared teardown for all JavaThreads
1877 void JavaThread::post_run() {
1878 this->exit(false);
1879 // Defer deletion to here to ensure 'this' is still referenceable in call_run
1880 // for any shared tear-down.
1881 this->smr_delete();
1882 }
1883
1884 static void ensure_join(JavaThread* thread) {
1885 // We do not need to grab the Threads_lock, since we are operating on ourself.
1886 Handle threadObj(thread, thread->threadObj());
1887 assert(threadObj.not_null(), "java thread object must exist");
1888 ObjectLocker lock(threadObj, thread);
1889 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1890 thread->clear_pending_exception();
1891 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1892 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1893 // Clear the native thread instance - this makes isAlive return false and allows the join()
1894 // to complete once we've done the notify_all below
1895 java_lang_Thread::set_thread(threadObj(), NULL);
1896 lock.notify_all(thread);
1897 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1898 thread->clear_pending_exception();
1899 }
1900
1901 static bool is_daemon(oop threadObj) {
1902 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
1903 }
1904
1905 // For any new cleanup additions, please check to see if they need to be applied to
1906 // cleanup_failed_attach_current_thread as well.
1907 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1908 assert(this == JavaThread::current(), "thread consistency check");
1909
1910 elapsedTimer _timer_exit_phase1;
1911 elapsedTimer _timer_exit_phase2;
1912 elapsedTimer _timer_exit_phase3;
1913 elapsedTimer _timer_exit_phase4;
1914
1915 if (log_is_enabled(Debug, os, thread, timer)) {
1916 _timer_exit_phase1.start();
1917 }
1918
1919 HandleMark hm(this);
1920 Handle uncaught_exception(this, this->pending_exception());
1921 this->clear_pending_exception();
1922 Handle threadObj(this, this->threadObj());
1923 assert(threadObj.not_null(), "Java thread object should be created");
1924
1925 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1926 {
1927 EXCEPTION_MARK;
1928
1929 CLEAR_PENDING_EXCEPTION;
1930 }
1931 if (!destroy_vm) {
1932 if (uncaught_exception.not_null()) {
1933 EXCEPTION_MARK;
1934 // Call method Thread.dispatchUncaughtException().
1935 Klass* thread_klass = SystemDictionary::Thread_klass();
1936 JavaValue result(T_VOID);
1937 JavaCalls::call_virtual(&result,
1938 threadObj, thread_klass,
1939 vmSymbols::dispatchUncaughtException_name(),
1940 vmSymbols::throwable_void_signature(),
1941 uncaught_exception,
1942 THREAD);
1943 if (HAS_PENDING_EXCEPTION) {
1944 ResourceMark rm(this);
1945 jio_fprintf(defaultStream::error_stream(),
1946 "\nException: %s thrown from the UncaughtExceptionHandler"
1947 " in thread \"%s\"\n",
1948 pending_exception()->klass()->external_name(),
1949 get_thread_name());
1950 CLEAR_PENDING_EXCEPTION;
1951 }
1952 }
1953 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
1954
1955 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1956 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1957 // is deprecated anyhow.
1958 if (!is_Compiler_thread()) {
1959 int count = 3;
1960 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1961 EXCEPTION_MARK;
1962 JavaValue result(T_VOID);
1963 Klass* thread_klass = SystemDictionary::Thread_klass();
1964 JavaCalls::call_virtual(&result,
1965 threadObj, thread_klass,
1966 vmSymbols::exit_method_name(),
1967 vmSymbols::void_method_signature(),
1968 THREAD);
1969 CLEAR_PENDING_EXCEPTION;
1970 }
1971 }
1972 // notify JVMTI
1973 if (JvmtiExport::should_post_thread_life()) {
1974 JvmtiExport::post_thread_end(this);
1975 }
1976
1977 // We have notified the agents that we are exiting, before we go on,
1978 // we must check for a pending external suspend request and honor it
1979 // in order to not surprise the thread that made the suspend request.
1980 while (true) {
1981 {
1982 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1983 if (!is_external_suspend()) {
1984 set_terminated(_thread_exiting);
1985 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
1986 break;
1987 }
1988 // Implied else:
1989 // Things get a little tricky here. We have a pending external
1990 // suspend request, but we are holding the SR_lock so we
1991 // can't just self-suspend. So we temporarily drop the lock
1992 // and then self-suspend.
1993 }
1994
1995 ThreadBlockInVM tbivm(this);
1996 java_suspend_self();
1997
1998 // We're done with this suspend request, but we have to loop around
1999 // and check again. Eventually we will get SR_lock without a pending
2000 // external suspend request and will be able to mark ourselves as
2001 // exiting.
2002 }
2003 // no more external suspends are allowed at this point
2004 } else {
2005 assert(!is_terminated() && !is_exiting(), "must not be exiting");
2006 // before_exit() has already posted JVMTI THREAD_END events
2007 }
2008
2009 if (log_is_enabled(Debug, os, thread, timer)) {
2010 _timer_exit_phase1.stop();
2011 _timer_exit_phase2.start();
2012 }
2013 // Notify waiters on thread object. This has to be done after exit() is called
2014 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
2015 // group should have the destroyed bit set before waiters are notified).
2016 ensure_join(this);
2017 assert(!this->has_pending_exception(), "ensure_join should have cleared");
2018
2019 if (log_is_enabled(Debug, os, thread, timer)) {
2020 _timer_exit_phase2.stop();
2021 _timer_exit_phase3.start();
2022 }
2023 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
2024 // held by this thread must be released. The spec does not distinguish
2025 // between JNI-acquired and regular Java monitors. We can only see
2026 // regular Java monitors here if monitor enter-exit matching is broken.
2027 //
2028 // ensure_join() ignores IllegalThreadStateExceptions, and so does
2029 // ObjectSynchronizer::release_monitors_owned_by_thread().
2030 if (exit_type == jni_detach) {
2031 // Sanity check even though JNI DetachCurrentThread() would have
2032 // returned JNI_ERR if there was a Java frame. JavaThread exit
2033 // should be done executing Java code by the time we get here.
2034 assert(!this->has_last_Java_frame(),
2035 "should not have a Java frame when detaching or exiting");
2036 ObjectSynchronizer::release_monitors_owned_by_thread(this);
2037 assert(!this->has_pending_exception(), "release_monitors should have cleared");
2038 }
2039
2040 // These things needs to be done while we are still a Java Thread. Make sure that thread
2041 // is in a consistent state, in case GC happens
2042 JFR_ONLY(Jfr::on_thread_exit(this);)
2043
2044 if (active_handles() != NULL) {
2045 JNIHandleBlock* block = active_handles();
2046 set_active_handles(NULL);
2047 JNIHandleBlock::release_block(block);
2048 }
2049
2050 if (free_handle_block() != NULL) {
2051 JNIHandleBlock* block = free_handle_block();
2052 set_free_handle_block(NULL);
2053 JNIHandleBlock::release_block(block);
2054 }
2055
2056 // These have to be removed while this is still a valid thread.
2057 remove_stack_guard_pages();
2058
2059 if (UseTLAB) {
2060 tlab().retire();
2061 }
2062
2063 if (JvmtiEnv::environments_might_exist()) {
2064 JvmtiExport::cleanup_thread(this);
2065 }
2066
2067 // We must flush any deferred card marks and other various GC barrier
2068 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2069 // before removing a thread from the list of active threads.
2070 BarrierSet::barrier_set()->on_thread_detach(this);
2071
2072 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2073 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2074 os::current_thread_id());
2075
2076 if (log_is_enabled(Debug, os, thread, timer)) {
2077 _timer_exit_phase3.stop();
2078 _timer_exit_phase4.start();
2079 }
2080 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2081 Threads::remove(this);
2082
2083 if (log_is_enabled(Debug, os, thread, timer)) {
2084 _timer_exit_phase4.stop();
2085 ResourceMark rm(this);
2086 log_debug(os, thread, timer)("name='%s'"
2087 ", exit-phase1=" JLONG_FORMAT
2088 ", exit-phase2=" JLONG_FORMAT
2089 ", exit-phase3=" JLONG_FORMAT
2090 ", exit-phase4=" JLONG_FORMAT,
2091 get_thread_name(),
2092 _timer_exit_phase1.milliseconds(),
2093 _timer_exit_phase2.milliseconds(),
2094 _timer_exit_phase3.milliseconds(),
2095 _timer_exit_phase4.milliseconds());
2096 }
2097 }
2098
2099 void JavaThread::cleanup_failed_attach_current_thread() {
2100 if (active_handles() != NULL) {
2101 JNIHandleBlock* block = active_handles();
2102 set_active_handles(NULL);
2103 JNIHandleBlock::release_block(block);
2104 }
2105
2106 if (free_handle_block() != NULL) {
2107 JNIHandleBlock* block = free_handle_block();
2108 set_free_handle_block(NULL);
2109 JNIHandleBlock::release_block(block);
2110 }
2111
2112 // These have to be removed while this is still a valid thread.
2113 remove_stack_guard_pages();
2114
2115 if (UseTLAB) {
2116 tlab().retire();
2117 }
2118
2119 BarrierSet::barrier_set()->on_thread_detach(this);
2120
2121 Threads::remove(this);
2122 this->smr_delete();
2123 }
2124
2125 JavaThread* JavaThread::active() {
2126 Thread* thread = Thread::current();
2127 if (thread->is_Java_thread()) {
2128 return (JavaThread*) thread;
2129 } else {
2130 assert(thread->is_VM_thread(), "this must be a vm thread");
2131 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2132 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2133 assert(ret->is_Java_thread(), "must be a Java thread");
2134 return ret;
2135 }
2136 }
2137
2138 bool JavaThread::is_lock_owned(address adr) const {
2139 if (Thread::is_lock_owned(adr)) return true;
2140
2141 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2142 if (chunk->contains(adr)) return true;
2143 }
2144
2145 return false;
2146 }
2147
2148
2149 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2150 chunk->set_next(monitor_chunks());
2151 set_monitor_chunks(chunk);
2152 }
2153
2154 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2155 guarantee(monitor_chunks() != NULL, "must be non empty");
2156 if (monitor_chunks() == chunk) {
2157 set_monitor_chunks(chunk->next());
2158 } else {
2159 MonitorChunk* prev = monitor_chunks();
2160 while (prev->next() != chunk) prev = prev->next();
2161 prev->set_next(chunk->next());
2162 }
2163 }
2164
2165 // JVM support.
2166
2167 // Note: this function shouldn't block if it's called in
2168 // _thread_in_native_trans state (such as from
2169 // check_special_condition_for_native_trans()).
2170 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2171
2172 if (has_last_Java_frame() && has_async_condition()) {
2173 // If we are at a polling page safepoint (not a poll return)
2174 // then we must defer async exception because live registers
2175 // will be clobbered by the exception path. Poll return is
2176 // ok because the call we a returning from already collides
2177 // with exception handling registers and so there is no issue.
2178 // (The exception handling path kills call result registers but
2179 // this is ok since the exception kills the result anyway).
2180
2181 if (is_at_poll_safepoint()) {
2182 // if the code we are returning to has deoptimized we must defer
2183 // the exception otherwise live registers get clobbered on the
2184 // exception path before deoptimization is able to retrieve them.
2185 //
2186 RegisterMap map(this, false);
2187 frame caller_fr = last_frame().sender(&map);
2188 assert(caller_fr.is_compiled_frame(), "what?");
2189 if (caller_fr.is_deoptimized_frame()) {
2190 log_info(exceptions)("deferred async exception at compiled safepoint");
2191 return;
2192 }
2193 }
2194 }
2195
2196 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2197 if (condition == _no_async_condition) {
2198 // Conditions have changed since has_special_runtime_exit_condition()
2199 // was called:
2200 // - if we were here only because of an external suspend request,
2201 // then that was taken care of above (or cancelled) so we are done
2202 // - if we were here because of another async request, then it has
2203 // been cleared between the has_special_runtime_exit_condition()
2204 // and now so again we are done
2205 return;
2206 }
2207
2208 // Check for pending async. exception
2209 if (_pending_async_exception != NULL) {
2210 // Only overwrite an already pending exception, if it is not a threadDeath.
2211 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2212
2213 // We cannot call Exceptions::_throw(...) here because we cannot block
2214 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2215
2216 LogTarget(Info, exceptions) lt;
2217 if (lt.is_enabled()) {
2218 ResourceMark rm;
2219 LogStream ls(lt);
2220 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2221 if (has_last_Java_frame()) {
2222 frame f = last_frame();
2223 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2224 }
2225 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2226 }
2227 _pending_async_exception = NULL;
2228 clear_has_async_exception();
2229 }
2230 }
2231
2232 if (check_unsafe_error &&
2233 condition == _async_unsafe_access_error && !has_pending_exception()) {
2234 condition = _no_async_condition; // done
2235 switch (thread_state()) {
2236 case _thread_in_vm: {
2237 JavaThread* THREAD = this;
2238 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2239 }
2240 case _thread_in_native: {
2241 ThreadInVMfromNative tiv(this);
2242 JavaThread* THREAD = this;
2243 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2244 }
2245 case _thread_in_Java: {
2246 ThreadInVMfromJava tiv(this);
2247 JavaThread* THREAD = this;
2248 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2249 }
2250 default:
2251 ShouldNotReachHere();
2252 }
2253 }
2254
2255 assert(condition == _no_async_condition || has_pending_exception() ||
2256 (!check_unsafe_error && condition == _async_unsafe_access_error),
2257 "must have handled the async condition, if no exception");
2258 }
2259
2260 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2261 //
2262 // Check for pending external suspend. Internal suspend requests do
2263 // not use handle_special_runtime_exit_condition().
2264 // If JNIEnv proxies are allowed, don't self-suspend if the target
2265 // thread is not the current thread. In older versions of jdbx, jdbx
2266 // threads could call into the VM with another thread's JNIEnv so we
2267 // can be here operating on behalf of a suspended thread (4432884).
2268 bool do_self_suspend = is_external_suspend_with_lock();
2269 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2270 //
2271 // Because thread is external suspended the safepoint code will count
2272 // thread as at a safepoint. This can be odd because we can be here
2273 // as _thread_in_Java which would normally transition to _thread_blocked
2274 // at a safepoint. We would like to mark the thread as _thread_blocked
2275 // before calling java_suspend_self like all other callers of it but
2276 // we must then observe proper safepoint protocol. (We can't leave
2277 // _thread_blocked with a safepoint in progress). However we can be
2278 // here as _thread_in_native_trans so we can't use a normal transition
2279 // constructor/destructor pair because they assert on that type of
2280 // transition. We could do something like:
2281 //
2282 // JavaThreadState state = thread_state();
2283 // set_thread_state(_thread_in_vm);
2284 // {
2285 // ThreadBlockInVM tbivm(this);
2286 // java_suspend_self()
2287 // }
2288 // set_thread_state(_thread_in_vm_trans);
2289 // if (safepoint) block;
2290 // set_thread_state(state);
2291 //
2292 // but that is pretty messy. Instead we just go with the way the
2293 // code has worked before and note that this is the only path to
2294 // java_suspend_self that doesn't put the thread in _thread_blocked
2295 // mode.
2296
2297 frame_anchor()->make_walkable(this);
2298 java_suspend_self();
2299
2300 // We might be here for reasons in addition to the self-suspend request
2301 // so check for other async requests.
2302 }
2303
2304 if (check_asyncs) {
2305 check_and_handle_async_exceptions();
2306 }
2307
2308 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2309 }
2310
2311 void JavaThread::send_thread_stop(oop java_throwable) {
2312 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2313 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2314 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2315
2316 // Do not throw asynchronous exceptions against the compiler thread
2317 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2318 if (!can_call_java()) return;
2319
2320 {
2321 // Actually throw the Throwable against the target Thread - however
2322 // only if there is no thread death exception installed already.
2323 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2324 // If the topmost frame is a runtime stub, then we are calling into
2325 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2326 // must deoptimize the caller before continuing, as the compiled exception handler table
2327 // may not be valid
2328 if (has_last_Java_frame()) {
2329 frame f = last_frame();
2330 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2331 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2332 RegisterMap reg_map(this, UseBiasedLocking);
2333 frame compiled_frame = f.sender(®_map);
2334 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2335 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2336 }
2337 }
2338 }
2339
2340 // Set async. pending exception in thread.
2341 set_pending_async_exception(java_throwable);
2342
2343 if (log_is_enabled(Info, exceptions)) {
2344 ResourceMark rm;
2345 log_info(exceptions)("Pending Async. exception installed of type: %s",
2346 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2347 }
2348 // for AbortVMOnException flag
2349 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2350 }
2351 }
2352
2353
2354 // Interrupt thread so it will wake up from a potential wait()
2355 Thread::interrupt(this);
2356 }
2357
2358 // External suspension mechanism.
2359 //
2360 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2361 // to any VM_locks and it is at a transition
2362 // Self-suspension will happen on the transition out of the vm.
2363 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2364 //
2365 // Guarantees on return:
2366 // + Target thread will not execute any new bytecode (that's why we need to
2367 // force a safepoint)
2368 // + Target thread will not enter any new monitors
2369 //
2370 void JavaThread::java_suspend() {
2371 ThreadsListHandle tlh;
2372 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2373 return;
2374 }
2375
2376 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2377 if (!is_external_suspend()) {
2378 // a racing resume has cancelled us; bail out now
2379 return;
2380 }
2381
2382 // suspend is done
2383 uint32_t debug_bits = 0;
2384 // Warning: is_ext_suspend_completed() may temporarily drop the
2385 // SR_lock to allow the thread to reach a stable thread state if
2386 // it is currently in a transient thread state.
2387 if (is_ext_suspend_completed(false /* !called_by_wait */,
2388 SuspendRetryDelay, &debug_bits)) {
2389 return;
2390 }
2391 }
2392
2393 VM_ThreadSuspend vm_suspend;
2394 VMThread::execute(&vm_suspend);
2395 }
2396
2397 // Part II of external suspension.
2398 // A JavaThread self suspends when it detects a pending external suspend
2399 // request. This is usually on transitions. It is also done in places
2400 // where continuing to the next transition would surprise the caller,
2401 // e.g., monitor entry.
2402 //
2403 // Returns the number of times that the thread self-suspended.
2404 //
2405 // Note: DO NOT call java_suspend_self() when you just want to block current
2406 // thread. java_suspend_self() is the second stage of cooperative
2407 // suspension for external suspend requests and should only be used
2408 // to complete an external suspend request.
2409 //
2410 int JavaThread::java_suspend_self() {
2411 int ret = 0;
2412
2413 // we are in the process of exiting so don't suspend
2414 if (is_exiting()) {
2415 clear_external_suspend();
2416 return ret;
2417 }
2418
2419 assert(_anchor.walkable() ||
2420 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2421 "must have walkable stack");
2422
2423 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2424
2425 assert(!this->is_ext_suspended(),
2426 "a thread trying to self-suspend should not already be suspended");
2427
2428 if (this->is_suspend_equivalent()) {
2429 // If we are self-suspending as a result of the lifting of a
2430 // suspend equivalent condition, then the suspend_equivalent
2431 // flag is not cleared until we set the ext_suspended flag so
2432 // that wait_for_ext_suspend_completion() returns consistent
2433 // results.
2434 this->clear_suspend_equivalent();
2435 }
2436
2437 // A racing resume may have cancelled us before we grabbed SR_lock
2438 // above. Or another external suspend request could be waiting for us
2439 // by the time we return from SR_lock()->wait(). The thread
2440 // that requested the suspension may already be trying to walk our
2441 // stack and if we return now, we can change the stack out from under
2442 // it. This would be a "bad thing (TM)" and cause the stack walker
2443 // to crash. We stay self-suspended until there are no more pending
2444 // external suspend requests.
2445 while (is_external_suspend()) {
2446 ret++;
2447 this->set_ext_suspended();
2448
2449 // _ext_suspended flag is cleared by java_resume()
2450 while (is_ext_suspended()) {
2451 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2452 }
2453 }
2454
2455 return ret;
2456 }
2457
2458 #ifdef ASSERT
2459 // Verify the JavaThread has not yet been published in the Threads::list, and
2460 // hence doesn't need protection from concurrent access at this stage.
2461 void JavaThread::verify_not_published() {
2462 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2463 // since an unpublished JavaThread doesn't participate in the
2464 // Thread-SMR protocol for keeping a ThreadsList alive.
2465 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2466 }
2467 #endif
2468
2469 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2470 // progress or when _suspend_flags is non-zero.
2471 // Current thread needs to self-suspend if there is a suspend request and/or
2472 // block if a safepoint is in progress.
2473 // Async exception ISN'T checked.
2474 // Note only the ThreadInVMfromNative transition can call this function
2475 // directly and when thread state is _thread_in_native_trans
2476 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2477 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2478
2479 JavaThread *curJT = JavaThread::current();
2480 bool do_self_suspend = thread->is_external_suspend();
2481
2482 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2483
2484 // If JNIEnv proxies are allowed, don't self-suspend if the target
2485 // thread is not the current thread. In older versions of jdbx, jdbx
2486 // threads could call into the VM with another thread's JNIEnv so we
2487 // can be here operating on behalf of a suspended thread (4432884).
2488 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2489 JavaThreadState state = thread->thread_state();
2490
2491 // We mark this thread_blocked state as a suspend-equivalent so
2492 // that a caller to is_ext_suspend_completed() won't be confused.
2493 // The suspend-equivalent state is cleared by java_suspend_self().
2494 thread->set_suspend_equivalent();
2495
2496 // If the safepoint code sees the _thread_in_native_trans state, it will
2497 // wait until the thread changes to other thread state. There is no
2498 // guarantee on how soon we can obtain the SR_lock and complete the
2499 // self-suspend request. It would be a bad idea to let safepoint wait for
2500 // too long. Temporarily change the state to _thread_blocked to
2501 // let the VM thread know that this thread is ready for GC. The problem
2502 // of changing thread state is that safepoint could happen just after
2503 // java_suspend_self() returns after being resumed, and VM thread will
2504 // see the _thread_blocked state. We must check for safepoint
2505 // after restoring the state and make sure we won't leave while a safepoint
2506 // is in progress.
2507 thread->set_thread_state(_thread_blocked);
2508 thread->java_suspend_self();
2509 thread->set_thread_state(state);
2510
2511 InterfaceSupport::serialize_thread_state_with_handler(thread);
2512 }
2513
2514 SafepointMechanism::block_if_requested(curJT);
2515
2516 if (thread->is_deopt_suspend()) {
2517 thread->clear_deopt_suspend();
2518 RegisterMap map(thread, false);
2519 frame f = thread->last_frame();
2520 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2521 f = f.sender(&map);
2522 }
2523 if (f.id() == thread->must_deopt_id()) {
2524 thread->clear_must_deopt_id();
2525 f.deoptimize(thread);
2526 } else {
2527 fatal("missed deoptimization!");
2528 }
2529 }
2530
2531 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2532 }
2533
2534 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2535 // progress or when _suspend_flags is non-zero.
2536 // Current thread needs to self-suspend if there is a suspend request and/or
2537 // block if a safepoint is in progress.
2538 // Also check for pending async exception (not including unsafe access error).
2539 // Note only the native==>VM/Java barriers can call this function and when
2540 // thread state is _thread_in_native_trans.
2541 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2542 check_safepoint_and_suspend_for_native_trans(thread);
2543
2544 if (thread->has_async_exception()) {
2545 // We are in _thread_in_native_trans state, don't handle unsafe
2546 // access error since that may block.
2547 thread->check_and_handle_async_exceptions(false);
2548 }
2549 }
2550
2551 // This is a variant of the normal
2552 // check_special_condition_for_native_trans with slightly different
2553 // semantics for use by critical native wrappers. It does all the
2554 // normal checks but also performs the transition back into
2555 // thread_in_Java state. This is required so that critical natives
2556 // can potentially block and perform a GC if they are the last thread
2557 // exiting the GCLocker.
2558 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2559 check_special_condition_for_native_trans(thread);
2560
2561 // Finish the transition
2562 thread->set_thread_state(_thread_in_Java);
2563
2564 if (thread->do_critical_native_unlock()) {
2565 ThreadInVMfromJavaNoAsyncException tiv(thread);
2566 GCLocker::unlock_critical(thread);
2567 thread->clear_critical_native_unlock();
2568 }
2569 }
2570
2571 // We need to guarantee the Threads_lock here, since resumes are not
2572 // allowed during safepoint synchronization
2573 // Can only resume from an external suspension
2574 void JavaThread::java_resume() {
2575 assert_locked_or_safepoint(Threads_lock);
2576
2577 // Sanity check: thread is gone, has started exiting or the thread
2578 // was not externally suspended.
2579 ThreadsListHandle tlh;
2580 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2581 return;
2582 }
2583
2584 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2585
2586 clear_external_suspend();
2587
2588 if (is_ext_suspended()) {
2589 clear_ext_suspended();
2590 SR_lock()->notify_all();
2591 }
2592 }
2593
2594 size_t JavaThread::_stack_red_zone_size = 0;
2595 size_t JavaThread::_stack_yellow_zone_size = 0;
2596 size_t JavaThread::_stack_reserved_zone_size = 0;
2597 size_t JavaThread::_stack_shadow_zone_size = 0;
2598
2599 void JavaThread::create_stack_guard_pages() {
2600 if (!os::uses_stack_guard_pages() ||
2601 _stack_guard_state != stack_guard_unused ||
2602 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2603 log_info(os, thread)("Stack guard page creation for thread "
2604 UINTX_FORMAT " disabled", os::current_thread_id());
2605 return;
2606 }
2607 address low_addr = stack_end();
2608 size_t len = stack_guard_zone_size();
2609
2610 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2611 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2612
2613 int must_commit = os::must_commit_stack_guard_pages();
2614 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2615
2616 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2617 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2618 return;
2619 }
2620
2621 if (os::guard_memory((char *) low_addr, len)) {
2622 _stack_guard_state = stack_guard_enabled;
2623 } else {
2624 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2625 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2626 if (os::uncommit_memory((char *) low_addr, len)) {
2627 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2628 }
2629 return;
2630 }
2631
2632 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2633 PTR_FORMAT "-" PTR_FORMAT ".",
2634 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2635 }
2636
2637 void JavaThread::remove_stack_guard_pages() {
2638 assert(Thread::current() == this, "from different thread");
2639 if (_stack_guard_state == stack_guard_unused) return;
2640 address low_addr = stack_end();
2641 size_t len = stack_guard_zone_size();
2642
2643 if (os::must_commit_stack_guard_pages()) {
2644 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2645 _stack_guard_state = stack_guard_unused;
2646 } else {
2647 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2648 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2649 return;
2650 }
2651 } else {
2652 if (_stack_guard_state == stack_guard_unused) return;
2653 if (os::unguard_memory((char *) low_addr, len)) {
2654 _stack_guard_state = stack_guard_unused;
2655 } else {
2656 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2657 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2658 return;
2659 }
2660 }
2661
2662 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2663 PTR_FORMAT "-" PTR_FORMAT ".",
2664 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2665 }
2666
2667 void JavaThread::enable_stack_reserved_zone() {
2668 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state");
2669
2670 // The base notation is from the stack's point of view, growing downward.
2671 // We need to adjust it to work correctly with guard_memory()
2672 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2673
2674 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2675 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2676
2677 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2678 _stack_guard_state = stack_guard_enabled;
2679 } else {
2680 warning("Attempt to guard stack reserved zone failed.");
2681 }
2682 enable_register_stack_guard();
2683 }
2684
2685 void JavaThread::disable_stack_reserved_zone() {
2686 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state");
2687
2688 // Simply return if called for a thread that does not use guard pages.
2689 if (_stack_guard_state != stack_guard_enabled) return;
2690
2691 // The base notation is from the stack's point of view, growing downward.
2692 // We need to adjust it to work correctly with guard_memory()
2693 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2694
2695 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2696 _stack_guard_state = stack_guard_reserved_disabled;
2697 } else {
2698 warning("Attempt to unguard stack reserved zone failed.");
2699 }
2700 disable_register_stack_guard();
2701 }
2702
2703 void JavaThread::enable_stack_yellow_reserved_zone() {
2704 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2705 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2706
2707 // The base notation is from the stacks point of view, growing downward.
2708 // We need to adjust it to work correctly with guard_memory()
2709 address base = stack_red_zone_base();
2710
2711 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2712 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2713
2714 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2715 _stack_guard_state = stack_guard_enabled;
2716 } else {
2717 warning("Attempt to guard stack yellow zone failed.");
2718 }
2719 enable_register_stack_guard();
2720 }
2721
2722 void JavaThread::disable_stack_yellow_reserved_zone() {
2723 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2724 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2725
2726 // Simply return if called for a thread that does not use guard pages.
2727 if (_stack_guard_state == stack_guard_unused) return;
2728
2729 // The base notation is from the stacks point of view, growing downward.
2730 // We need to adjust it to work correctly with guard_memory()
2731 address base = stack_red_zone_base();
2732
2733 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2734 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2735 } else {
2736 warning("Attempt to unguard stack yellow zone failed.");
2737 }
2738 disable_register_stack_guard();
2739 }
2740
2741 void JavaThread::enable_stack_red_zone() {
2742 // The base notation is from the stacks point of view, growing downward.
2743 // We need to adjust it to work correctly with guard_memory()
2744 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2745 address base = stack_red_zone_base() - stack_red_zone_size();
2746
2747 guarantee(base < stack_base(), "Error calculating stack red zone");
2748 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2749
2750 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2751 warning("Attempt to guard stack red zone failed.");
2752 }
2753 }
2754
2755 void JavaThread::disable_stack_red_zone() {
2756 // The base notation is from the stacks point of view, growing downward.
2757 // We need to adjust it to work correctly with guard_memory()
2758 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2759 address base = stack_red_zone_base() - stack_red_zone_size();
2760 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2761 warning("Attempt to unguard stack red zone failed.");
2762 }
2763 }
2764
2765 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2766 // ignore is there is no stack
2767 if (!has_last_Java_frame()) return;
2768 // traverse the stack frames. Starts from top frame.
2769 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2770 frame* fr = fst.current();
2771 f(fr, fst.register_map());
2772 }
2773 }
2774
2775
2776 #ifndef PRODUCT
2777 // Deoptimization
2778 // Function for testing deoptimization
2779 void JavaThread::deoptimize() {
2780 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2781 StackFrameStream fst(this, UseBiasedLocking);
2782 bool deopt = false; // Dump stack only if a deopt actually happens.
2783 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2784 // Iterate over all frames in the thread and deoptimize
2785 for (; !fst.is_done(); fst.next()) {
2786 if (fst.current()->can_be_deoptimized()) {
2787
2788 if (only_at) {
2789 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2790 // consists of comma or carriage return separated numbers so
2791 // search for the current bci in that string.
2792 address pc = fst.current()->pc();
2793 nmethod* nm = (nmethod*) fst.current()->cb();
2794 ScopeDesc* sd = nm->scope_desc_at(pc);
2795 char buffer[8];
2796 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2797 size_t len = strlen(buffer);
2798 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2799 while (found != NULL) {
2800 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2801 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2802 // Check that the bci found is bracketed by terminators.
2803 break;
2804 }
2805 found = strstr(found + 1, buffer);
2806 }
2807 if (!found) {
2808 continue;
2809 }
2810 }
2811
2812 if (DebugDeoptimization && !deopt) {
2813 deopt = true; // One-time only print before deopt
2814 tty->print_cr("[BEFORE Deoptimization]");
2815 trace_frames();
2816 trace_stack();
2817 }
2818 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2819 }
2820 }
2821
2822 if (DebugDeoptimization && deopt) {
2823 tty->print_cr("[AFTER Deoptimization]");
2824 trace_frames();
2825 }
2826 }
2827
2828
2829 // Make zombies
2830 void JavaThread::make_zombies() {
2831 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2832 if (fst.current()->can_be_deoptimized()) {
2833 // it is a Java nmethod
2834 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2835 nm->make_not_entrant();
2836 }
2837 }
2838 }
2839 #endif // PRODUCT
2840
2841
2842 void JavaThread::deoptimized_wrt_marked_nmethods() {
2843 if (!has_last_Java_frame()) return;
2844 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2845 StackFrameStream fst(this, UseBiasedLocking);
2846 for (; !fst.is_done(); fst.next()) {
2847 if (fst.current()->should_be_deoptimized()) {
2848 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2849 }
2850 }
2851 }
2852
2853
2854 // If the caller is a NamedThread, then remember, in the current scope,
2855 // the given JavaThread in its _processed_thread field.
2856 class RememberProcessedThread: public StackObj {
2857 NamedThread* _cur_thr;
2858 public:
2859 RememberProcessedThread(JavaThread* jthr) {
2860 Thread* thread = Thread::current();
2861 if (thread->is_Named_thread()) {
2862 _cur_thr = (NamedThread *)thread;
2863 _cur_thr->set_processed_thread(jthr);
2864 } else {
2865 _cur_thr = NULL;
2866 }
2867 }
2868
2869 ~RememberProcessedThread() {
2870 if (_cur_thr) {
2871 _cur_thr->set_processed_thread(NULL);
2872 }
2873 }
2874 };
2875
2876 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2877 // Verify that the deferred card marks have been flushed.
2878 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2879
2880 // Traverse the GCHandles
2881 Thread::oops_do(f, cf);
2882
2883 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2884 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2885
2886 if (has_last_Java_frame()) {
2887 // Record JavaThread to GC thread
2888 RememberProcessedThread rpt(this);
2889
2890 // traverse the registered growable array
2891 if (_array_for_gc != NULL) {
2892 for (int index = 0; index < _array_for_gc->length(); index++) {
2893 f->do_oop(_array_for_gc->adr_at(index));
2894 }
2895 }
2896
2897 // Traverse the monitor chunks
2898 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2899 chunk->oops_do(f);
2900 }
2901
2902 // Traverse the execution stack
2903 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2904 fst.current()->oops_do(f, cf, fst.register_map());
2905 }
2906 }
2907
2908 // callee_target is never live across a gc point so NULL it here should
2909 // it still contain a methdOop.
2910
2911 set_callee_target(NULL);
2912
2913 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2914 // If we have deferred set_locals there might be oops waiting to be
2915 // written
2916 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2917 if (list != NULL) {
2918 for (int i = 0; i < list->length(); i++) {
2919 list->at(i)->oops_do(f);
2920 }
2921 }
2922
2923 // Traverse instance variables at the end since the GC may be moving things
2924 // around using this function
2925 f->do_oop((oop*) &_threadObj);
2926 f->do_oop((oop*) &_vm_result);
2927 f->do_oop((oop*) &_exception_oop);
2928 f->do_oop((oop*) &_pending_async_exception);
2929
2930 if (jvmti_thread_state() != NULL) {
2931 jvmti_thread_state()->oops_do(f);
2932 }
2933 }
2934
2935 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2936 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2937 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2938
2939 if (has_last_Java_frame()) {
2940 // Traverse the execution stack
2941 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2942 fst.current()->nmethods_do(cf);
2943 }
2944 }
2945 }
2946
2947 void JavaThread::metadata_do(void f(Metadata*)) {
2948 if (has_last_Java_frame()) {
2949 // Traverse the execution stack to call f() on the methods in the stack
2950 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2951 fst.current()->metadata_do(f);
2952 }
2953 } else if (is_Compiler_thread()) {
2954 // need to walk ciMetadata in current compile tasks to keep alive.
2955 CompilerThread* ct = (CompilerThread*)this;
2956 if (ct->env() != NULL) {
2957 ct->env()->metadata_do(f);
2958 }
2959 CompileTask* task = ct->task();
2960 if (task != NULL) {
2961 task->metadata_do(f);
2962 }
2963 }
2964 }
2965
2966 // Printing
2967 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2968 switch (_thread_state) {
2969 case _thread_uninitialized: return "_thread_uninitialized";
2970 case _thread_new: return "_thread_new";
2971 case _thread_new_trans: return "_thread_new_trans";
2972 case _thread_in_native: return "_thread_in_native";
2973 case _thread_in_native_trans: return "_thread_in_native_trans";
2974 case _thread_in_vm: return "_thread_in_vm";
2975 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2976 case _thread_in_Java: return "_thread_in_Java";
2977 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2978 case _thread_blocked: return "_thread_blocked";
2979 case _thread_blocked_trans: return "_thread_blocked_trans";
2980 default: return "unknown thread state";
2981 }
2982 }
2983
2984 #ifndef PRODUCT
2985 void JavaThread::print_thread_state_on(outputStream *st) const {
2986 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2987 };
2988 void JavaThread::print_thread_state() const {
2989 print_thread_state_on(tty);
2990 }
2991 #endif // PRODUCT
2992
2993 // Called by Threads::print() for VM_PrintThreads operation
2994 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
2995 st->print_raw("\"");
2996 st->print_raw(get_thread_name());
2997 st->print_raw("\" ");
2998 oop thread_oop = threadObj();
2999 if (thread_oop != NULL) {
3000 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
3001 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
3002 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
3003 }
3004 Thread::print_on(st, print_extended_info);
3005 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
3006 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
3007 if (thread_oop != NULL) {
3008 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3009 }
3010 #ifndef PRODUCT
3011 _safepoint_state->print_on(st);
3012 #endif // PRODUCT
3013 if (is_Compiler_thread()) {
3014 CompileTask *task = ((CompilerThread*)this)->task();
3015 if (task != NULL) {
3016 st->print(" Compiling: ");
3017 task->print(st, NULL, true, false);
3018 } else {
3019 st->print(" No compile task");
3020 }
3021 st->cr();
3022 }
3023 }
3024
3025 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3026 st->print("%s", get_thread_name_string(buf, buflen));
3027 }
3028
3029 // Called by fatal error handler. The difference between this and
3030 // JavaThread::print() is that we can't grab lock or allocate memory.
3031 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3032 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3033 oop thread_obj = threadObj();
3034 if (thread_obj != NULL) {
3035 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3036 }
3037 st->print(" [");
3038 st->print("%s", _get_thread_state_name(_thread_state));
3039 if (osthread()) {
3040 st->print(", id=%d", osthread()->thread_id());
3041 }
3042 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3043 p2i(stack_end()), p2i(stack_base()));
3044 st->print("]");
3045
3046 ThreadsSMRSupport::print_info_on(this, st);
3047 return;
3048 }
3049
3050 // Verification
3051
3052 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3053
3054 void JavaThread::verify() {
3055 // Verify oops in the thread.
3056 oops_do(&VerifyOopClosure::verify_oop, NULL);
3057
3058 // Verify the stack frames.
3059 frames_do(frame_verify);
3060 }
3061
3062 // CR 6300358 (sub-CR 2137150)
3063 // Most callers of this method assume that it can't return NULL but a
3064 // thread may not have a name whilst it is in the process of attaching to
3065 // the VM - see CR 6412693, and there are places where a JavaThread can be
3066 // seen prior to having it's threadObj set (eg JNI attaching threads and
3067 // if vm exit occurs during initialization). These cases can all be accounted
3068 // for such that this method never returns NULL.
3069 const char* JavaThread::get_thread_name() const {
3070 #ifdef ASSERT
3071 // early safepoints can hit while current thread does not yet have TLS
3072 if (!SafepointSynchronize::is_at_safepoint()) {
3073 Thread *cur = Thread::current();
3074 if (!(cur->is_Java_thread() && cur == this)) {
3075 // Current JavaThreads are allowed to get their own name without
3076 // the Threads_lock.
3077 assert_locked_or_safepoint(Threads_lock);
3078 }
3079 }
3080 #endif // ASSERT
3081 return get_thread_name_string();
3082 }
3083
3084 // Returns a non-NULL representation of this thread's name, or a suitable
3085 // descriptive string if there is no set name
3086 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3087 const char* name_str;
3088 oop thread_obj = threadObj();
3089 if (thread_obj != NULL) {
3090 oop name = java_lang_Thread::name(thread_obj);
3091 if (name != NULL) {
3092 if (buf == NULL) {
3093 name_str = java_lang_String::as_utf8_string(name);
3094 } else {
3095 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3096 }
3097 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3098 name_str = "<no-name - thread is attaching>";
3099 } else {
3100 name_str = Thread::name();
3101 }
3102 } else {
3103 name_str = Thread::name();
3104 }
3105 assert(name_str != NULL, "unexpected NULL thread name");
3106 return name_str;
3107 }
3108
3109
3110 const char* JavaThread::get_threadgroup_name() const {
3111 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3112 oop thread_obj = threadObj();
3113 if (thread_obj != NULL) {
3114 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3115 if (thread_group != NULL) {
3116 // ThreadGroup.name can be null
3117 return java_lang_ThreadGroup::name(thread_group);
3118 }
3119 }
3120 return NULL;
3121 }
3122
3123 const char* JavaThread::get_parent_name() const {
3124 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3125 oop thread_obj = threadObj();
3126 if (thread_obj != NULL) {
3127 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3128 if (thread_group != NULL) {
3129 oop parent = java_lang_ThreadGroup::parent(thread_group);
3130 if (parent != NULL) {
3131 // ThreadGroup.name can be null
3132 return java_lang_ThreadGroup::name(parent);
3133 }
3134 }
3135 }
3136 return NULL;
3137 }
3138
3139 ThreadPriority JavaThread::java_priority() const {
3140 oop thr_oop = threadObj();
3141 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3142 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3143 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3144 return priority;
3145 }
3146
3147 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3148
3149 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3150 // Link Java Thread object <-> C++ Thread
3151
3152 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3153 // and put it into a new Handle. The Handle "thread_oop" can then
3154 // be used to pass the C++ thread object to other methods.
3155
3156 // Set the Java level thread object (jthread) field of the
3157 // new thread (a JavaThread *) to C++ thread object using the
3158 // "thread_oop" handle.
3159
3160 // Set the thread field (a JavaThread *) of the
3161 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3162
3163 Handle thread_oop(Thread::current(),
3164 JNIHandles::resolve_non_null(jni_thread));
3165 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3166 "must be initialized");
3167 set_threadObj(thread_oop());
3168 java_lang_Thread::set_thread(thread_oop(), this);
3169
3170 if (prio == NoPriority) {
3171 prio = java_lang_Thread::priority(thread_oop());
3172 assert(prio != NoPriority, "A valid priority should be present");
3173 }
3174
3175 // Push the Java priority down to the native thread; needs Threads_lock
3176 Thread::set_priority(this, prio);
3177
3178 // Add the new thread to the Threads list and set it in motion.
3179 // We must have threads lock in order to call Threads::add.
3180 // It is crucial that we do not block before the thread is
3181 // added to the Threads list for if a GC happens, then the java_thread oop
3182 // will not be visited by GC.
3183 Threads::add(this);
3184 }
3185
3186 oop JavaThread::current_park_blocker() {
3187 // Support for JSR-166 locks
3188 oop thread_oop = threadObj();
3189 if (thread_oop != NULL &&
3190 JDK_Version::current().supports_thread_park_blocker()) {
3191 return java_lang_Thread::park_blocker(thread_oop);
3192 }
3193 return NULL;
3194 }
3195
3196
3197 void JavaThread::print_stack_on(outputStream* st) {
3198 if (!has_last_Java_frame()) return;
3199 ResourceMark rm;
3200 HandleMark hm;
3201
3202 RegisterMap reg_map(this);
3203 vframe* start_vf = last_java_vframe(®_map);
3204 int count = 0;
3205 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3206 if (f->is_java_frame()) {
3207 javaVFrame* jvf = javaVFrame::cast(f);
3208 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3209
3210 // Print out lock information
3211 if (JavaMonitorsInStackTrace) {
3212 jvf->print_lock_info_on(st, count);
3213 }
3214 } else {
3215 // Ignore non-Java frames
3216 }
3217
3218 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3219 count++;
3220 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3221 }
3222 }
3223
3224
3225 // JVMTI PopFrame support
3226 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3227 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3228 if (in_bytes(size_in_bytes) != 0) {
3229 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3230 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3231 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3232 }
3233 }
3234
3235 void* JavaThread::popframe_preserved_args() {
3236 return _popframe_preserved_args;
3237 }
3238
3239 ByteSize JavaThread::popframe_preserved_args_size() {
3240 return in_ByteSize(_popframe_preserved_args_size);
3241 }
3242
3243 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3244 int sz = in_bytes(popframe_preserved_args_size());
3245 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3246 return in_WordSize(sz / wordSize);
3247 }
3248
3249 void JavaThread::popframe_free_preserved_args() {
3250 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3251 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3252 _popframe_preserved_args = NULL;
3253 _popframe_preserved_args_size = 0;
3254 }
3255
3256 #ifndef PRODUCT
3257
3258 void JavaThread::trace_frames() {
3259 tty->print_cr("[Describe stack]");
3260 int frame_no = 1;
3261 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3262 tty->print(" %d. ", frame_no++);
3263 fst.current()->print_value_on(tty, this);
3264 tty->cr();
3265 }
3266 }
3267
3268 class PrintAndVerifyOopClosure: public OopClosure {
3269 protected:
3270 template <class T> inline void do_oop_work(T* p) {
3271 oop obj = RawAccess<>::oop_load(p);
3272 if (obj == NULL) return;
3273 tty->print(INTPTR_FORMAT ": ", p2i(p));
3274 if (oopDesc::is_oop_or_null(obj)) {
3275 if (obj->is_objArray()) {
3276 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3277 } else {
3278 obj->print();
3279 }
3280 } else {
3281 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3282 }
3283 tty->cr();
3284 }
3285 public:
3286 virtual void do_oop(oop* p) { do_oop_work(p); }
3287 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3288 };
3289
3290
3291 static void oops_print(frame* f, const RegisterMap *map) {
3292 PrintAndVerifyOopClosure print;
3293 f->print_value();
3294 f->oops_do(&print, NULL, (RegisterMap*)map);
3295 }
3296
3297 // Print our all the locations that contain oops and whether they are
3298 // valid or not. This useful when trying to find the oldest frame
3299 // where an oop has gone bad since the frame walk is from youngest to
3300 // oldest.
3301 void JavaThread::trace_oops() {
3302 tty->print_cr("[Trace oops]");
3303 frames_do(oops_print);
3304 }
3305
3306
3307 #ifdef ASSERT
3308 // Print or validate the layout of stack frames
3309 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3310 ResourceMark rm;
3311 PRESERVE_EXCEPTION_MARK;
3312 FrameValues values;
3313 int frame_no = 0;
3314 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3315 fst.current()->describe(values, ++frame_no);
3316 if (depth == frame_no) break;
3317 }
3318 if (validate_only) {
3319 values.validate();
3320 } else {
3321 tty->print_cr("[Describe stack layout]");
3322 values.print(this);
3323 }
3324 }
3325 #endif
3326
3327 void JavaThread::trace_stack_from(vframe* start_vf) {
3328 ResourceMark rm;
3329 int vframe_no = 1;
3330 for (vframe* f = start_vf; f; f = f->sender()) {
3331 if (f->is_java_frame()) {
3332 javaVFrame::cast(f)->print_activation(vframe_no++);
3333 } else {
3334 f->print();
3335 }
3336 if (vframe_no > StackPrintLimit) {
3337 tty->print_cr("...<more frames>...");
3338 return;
3339 }
3340 }
3341 }
3342
3343
3344 void JavaThread::trace_stack() {
3345 if (!has_last_Java_frame()) return;
3346 ResourceMark rm;
3347 HandleMark hm;
3348 RegisterMap reg_map(this);
3349 trace_stack_from(last_java_vframe(®_map));
3350 }
3351
3352
3353 #endif // PRODUCT
3354
3355
3356 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3357 assert(reg_map != NULL, "a map must be given");
3358 frame f = last_frame();
3359 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3360 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3361 }
3362 return NULL;
3363 }
3364
3365
3366 Klass* JavaThread::security_get_caller_class(int depth) {
3367 vframeStream vfst(this);
3368 vfst.security_get_caller_frame(depth);
3369 if (!vfst.at_end()) {
3370 return vfst.method()->method_holder();
3371 }
3372 return NULL;
3373 }
3374
3375 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3376 assert(thread->is_Compiler_thread(), "must be compiler thread");
3377 CompileBroker::compiler_thread_loop();
3378 }
3379
3380 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3381 NMethodSweeper::sweeper_loop();
3382 }
3383
3384 // Create a CompilerThread
3385 CompilerThread::CompilerThread(CompileQueue* queue,
3386 CompilerCounters* counters)
3387 : JavaThread(&compiler_thread_entry) {
3388 _env = NULL;
3389 _log = NULL;
3390 _task = NULL;
3391 _queue = queue;
3392 _counters = counters;
3393 _buffer_blob = NULL;
3394 _compiler = NULL;
3395
3396 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3397 resource_area()->bias_to(mtCompiler);
3398
3399 #ifndef PRODUCT
3400 _ideal_graph_printer = NULL;
3401 #endif
3402 }
3403
3404 CompilerThread::~CompilerThread() {
3405 // Delete objects which were allocated on heap.
3406 delete _counters;
3407 }
3408
3409 bool CompilerThread::can_call_java() const {
3410 return _compiler != NULL && _compiler->is_jvmci();
3411 }
3412
3413 // Create sweeper thread
3414 CodeCacheSweeperThread::CodeCacheSweeperThread()
3415 : JavaThread(&sweeper_thread_entry) {
3416 _scanned_compiled_method = NULL;
3417 }
3418
3419 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3420 JavaThread::oops_do(f, cf);
3421 if (_scanned_compiled_method != NULL && cf != NULL) {
3422 // Safepoints can occur when the sweeper is scanning an nmethod so
3423 // process it here to make sure it isn't unloaded in the middle of
3424 // a scan.
3425 cf->do_code_blob(_scanned_compiled_method);
3426 }
3427 }
3428
3429 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3430 JavaThread::nmethods_do(cf);
3431 if (_scanned_compiled_method != NULL && cf != NULL) {
3432 // Safepoints can occur when the sweeper is scanning an nmethod so
3433 // process it here to make sure it isn't unloaded in the middle of
3434 // a scan.
3435 cf->do_code_blob(_scanned_compiled_method);
3436 }
3437 }
3438
3439
3440 // ======= Threads ========
3441
3442 // The Threads class links together all active threads, and provides
3443 // operations over all threads. It is protected by the Threads_lock,
3444 // which is also used in other global contexts like safepointing.
3445 // ThreadsListHandles are used to safely perform operations on one
3446 // or more threads without the risk of the thread exiting during the
3447 // operation.
3448 //
3449 // Note: The Threads_lock is currently more widely used than we
3450 // would like. We are actively migrating Threads_lock uses to other
3451 // mechanisms in order to reduce Threads_lock contention.
3452
3453 JavaThread* Threads::_thread_list = NULL;
3454 int Threads::_number_of_threads = 0;
3455 int Threads::_number_of_non_daemon_threads = 0;
3456 int Threads::_return_code = 0;
3457 int Threads::_thread_claim_parity = 0;
3458 size_t JavaThread::_stack_size_at_create = 0;
3459
3460 #ifdef ASSERT
3461 bool Threads::_vm_complete = false;
3462 #endif
3463
3464 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3465 Prefetch::read((void*)addr, prefetch_interval);
3466 return *addr;
3467 }
3468
3469 // Possibly the ugliest for loop the world has seen. C++ does not allow
3470 // multiple types in the declaration section of the for loop. In this case
3471 // we are only dealing with pointers and hence can cast them. It looks ugly
3472 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3473 #define DO_JAVA_THREADS(LIST, X) \
3474 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3475 *MACRO_list = (JavaThread*)(LIST), \
3476 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3477 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3478 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3479 MACRO_current_p != MACRO_end; \
3480 MACRO_current_p++, \
3481 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3482
3483 // All JavaThreads
3484 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3485
3486 // All NonJavaThreads (i.e., every non-JavaThread in the system).
3487 void Threads::non_java_threads_do(ThreadClosure* tc) {
3488 NoSafepointVerifier nsv(!SafepointSynchronize::is_at_safepoint(), false);
3489 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
3490 tc->do_thread(njti.current());
3491 }
3492 }
3493
3494 // All JavaThreads
3495 void Threads::java_threads_do(ThreadClosure* tc) {
3496 assert_locked_or_safepoint(Threads_lock);
3497 // ALL_JAVA_THREADS iterates through all JavaThreads.
3498 ALL_JAVA_THREADS(p) {
3499 tc->do_thread(p);
3500 }
3501 }
3502
3503 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3504 assert_locked_or_safepoint(Threads_lock);
3505 java_threads_do(tc);
3506 tc->do_thread(VMThread::vm_thread());
3507 }
3508
3509 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3510 void Threads::threads_do(ThreadClosure* tc) {
3511 assert_locked_or_safepoint(Threads_lock);
3512 java_threads_do(tc);
3513 non_java_threads_do(tc);
3514 }
3515
3516 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3517 int cp = Threads::thread_claim_parity();
3518 ALL_JAVA_THREADS(p) {
3519 if (p->claim_oops_do(is_par, cp)) {
3520 tc->do_thread(p);
3521 }
3522 }
3523 VMThread* vmt = VMThread::vm_thread();
3524 if (vmt->claim_oops_do(is_par, cp)) {
3525 tc->do_thread(vmt);
3526 }
3527 }
3528
3529 // The system initialization in the library has three phases.
3530 //
3531 // Phase 1: java.lang.System class initialization
3532 // java.lang.System is a primordial class loaded and initialized
3533 // by the VM early during startup. java.lang.System.<clinit>
3534 // only does registerNatives and keeps the rest of the class
3535 // initialization work later until thread initialization completes.
3536 //
3537 // System.initPhase1 initializes the system properties, the static
3538 // fields in, out, and err. Set up java signal handlers, OS-specific
3539 // system settings, and thread group of the main thread.
3540 static void call_initPhase1(TRAPS) {
3541 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3542 JavaValue result(T_VOID);
3543 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3544 vmSymbols::void_method_signature(), CHECK);
3545 }
3546
3547 // Phase 2. Module system initialization
3548 // This will initialize the module system. Only java.base classes
3549 // can be loaded until phase 2 completes.
3550 //
3551 // Call System.initPhase2 after the compiler initialization and jsr292
3552 // classes get initialized because module initialization runs a lot of java
3553 // code, that for performance reasons, should be compiled. Also, this will
3554 // enable the startup code to use lambda and other language features in this
3555 // phase and onward.
3556 //
3557 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3558 static void call_initPhase2(TRAPS) {
3559 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3560
3561 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3562
3563 JavaValue result(T_INT);
3564 JavaCallArguments args;
3565 args.push_int(DisplayVMOutputToStderr);
3566 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3567 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3568 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3569 if (result.get_jint() != JNI_OK) {
3570 vm_exit_during_initialization(); // no message or exception
3571 }
3572
3573 universe_post_module_init();
3574 }
3575
3576 // Phase 3. final setup - set security manager, system class loader and TCCL
3577 //
3578 // This will instantiate and set the security manager, set the system class
3579 // loader as well as the thread context class loader. The security manager
3580 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3581 // other modules or the application's classpath.
3582 static void call_initPhase3(TRAPS) {
3583 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3584 JavaValue result(T_VOID);
3585 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3586 vmSymbols::void_method_signature(), CHECK);
3587 }
3588
3589 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3590 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3591
3592 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3593 create_vm_init_libraries();
3594 }
3595
3596 initialize_class(vmSymbols::java_lang_String(), CHECK);
3597
3598 // Inject CompactStrings value after the static initializers for String ran.
3599 java_lang_String::set_compact_strings(CompactStrings);
3600
3601 // Initialize java_lang.System (needed before creating the thread)
3602 initialize_class(vmSymbols::java_lang_System(), CHECK);
3603 // The VM creates & returns objects of this class. Make sure it's initialized.
3604 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3605 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3606 Handle thread_group = create_initial_thread_group(CHECK);
3607 Universe::set_main_thread_group(thread_group());
3608 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3609 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3610 main_thread->set_threadObj(thread_object);
3611 // Set thread status to running since main thread has
3612 // been started and running.
3613 java_lang_Thread::set_thread_status(thread_object,
3614 java_lang_Thread::RUNNABLE);
3615
3616 // The VM creates objects of this class.
3617 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3618
3619 // The VM preresolves methods to these classes. Make sure that they get initialized
3620 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3621 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3622
3623 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3624 call_initPhase1(CHECK);
3625
3626 // get the Java runtime name after java.lang.System is initialized
3627 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3628 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3629
3630 // an instance of OutOfMemory exception has been allocated earlier
3631 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3632 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3633 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3634 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3635 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3636 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3637 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3638 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3639 }
3640
3641 void Threads::initialize_jsr292_core_classes(TRAPS) {
3642 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3643
3644 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3645 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3646 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3647 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3648 }
3649
3650 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3651 extern void JDK_Version_init();
3652
3653 // Preinitialize version info.
3654 VM_Version::early_initialize();
3655
3656 // Check version
3657 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3658
3659 // Initialize library-based TLS
3660 ThreadLocalStorage::init();
3661
3662 // Initialize the output stream module
3663 ostream_init();
3664
3665 // Process java launcher properties.
3666 Arguments::process_sun_java_launcher_properties(args);
3667
3668 // Initialize the os module
3669 os::init();
3670
3671 // Record VM creation timing statistics
3672 TraceVmCreationTime create_vm_timer;
3673 create_vm_timer.start();
3674
3675 // Initialize system properties.
3676 Arguments::init_system_properties();
3677
3678 // So that JDK version can be used as a discriminator when parsing arguments
3679 JDK_Version_init();
3680
3681 // Update/Initialize System properties after JDK version number is known
3682 Arguments::init_version_specific_system_properties();
3683
3684 // Make sure to initialize log configuration *before* parsing arguments
3685 LogConfiguration::initialize(create_vm_timer.begin_time());
3686
3687 // Parse arguments
3688 // Note: this internally calls os::init_container_support()
3689 jint parse_result = Arguments::parse(args);
3690 if (parse_result != JNI_OK) return parse_result;
3691
3692 os::init_before_ergo();
3693
3694 jint ergo_result = Arguments::apply_ergo();
3695 if (ergo_result != JNI_OK) return ergo_result;
3696
3697 // Final check of all ranges after ergonomics which may change values.
3698 if (!JVMFlagRangeList::check_ranges()) {
3699 return JNI_EINVAL;
3700 }
3701
3702 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3703 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo);
3704 if (!constraint_result) {
3705 return JNI_EINVAL;
3706 }
3707
3708 JVMFlagWriteableList::mark_startup();
3709
3710 if (PauseAtStartup) {
3711 os::pause();
3712 }
3713
3714 HOTSPOT_VM_INIT_BEGIN();
3715
3716 // Timing (must come after argument parsing)
3717 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3718
3719 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3720 // Initialize assert poison page mechanism.
3721 if (ShowRegistersOnAssert) {
3722 initialize_assert_poison();
3723 }
3724 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3725
3726 // Initialize the os module after parsing the args
3727 jint os_init_2_result = os::init_2();
3728 if (os_init_2_result != JNI_OK) return os_init_2_result;
3729
3730 SafepointMechanism::initialize();
3731
3732 jint adjust_after_os_result = Arguments::adjust_after_os();
3733 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3734
3735 // Initialize output stream logging
3736 ostream_init_log();
3737
3738 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3739 // Must be before create_vm_init_agents()
3740 if (Arguments::init_libraries_at_startup()) {
3741 convert_vm_init_libraries_to_agents();
3742 }
3743
3744 // Launch -agentlib/-agentpath and converted -Xrun agents
3745 if (Arguments::init_agents_at_startup()) {
3746 create_vm_init_agents();
3747 }
3748
3749 // Initialize Threads state
3750 _thread_list = NULL;
3751 _number_of_threads = 0;
3752 _number_of_non_daemon_threads = 0;
3753
3754 // Initialize global data structures and create system classes in heap
3755 vm_init_globals();
3756
3757 #if INCLUDE_JVMCI
3758 if (JVMCICounterSize > 0) {
3759 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3760 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3761 } else {
3762 JavaThread::_jvmci_old_thread_counters = NULL;
3763 }
3764 #endif // INCLUDE_JVMCI
3765
3766 // Attach the main thread to this os thread
3767 JavaThread* main_thread = new JavaThread();
3768 main_thread->set_thread_state(_thread_in_vm);
3769 main_thread->initialize_thread_current();
3770 // must do this before set_active_handles
3771 main_thread->record_stack_base_and_size();
3772 main_thread->register_thread_stack_with_NMT();
3773 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3774
3775 if (!main_thread->set_as_starting_thread()) {
3776 vm_shutdown_during_initialization(
3777 "Failed necessary internal allocation. Out of swap space");
3778 main_thread->smr_delete();
3779 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3780 return JNI_ENOMEM;
3781 }
3782
3783 // Enable guard page *after* os::create_main_thread(), otherwise it would
3784 // crash Linux VM, see notes in os_linux.cpp.
3785 main_thread->create_stack_guard_pages();
3786
3787 // Initialize Java-Level synchronization subsystem
3788 ObjectMonitor::Initialize();
3789
3790 // Initialize global modules
3791 jint status = init_globals();
3792 if (status != JNI_OK) {
3793 main_thread->smr_delete();
3794 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3795 return status;
3796 }
3797
3798 JFR_ONLY(Jfr::on_vm_init();)
3799
3800 // Should be done after the heap is fully created
3801 main_thread->cache_global_variables();
3802
3803 HandleMark hm;
3804
3805 { MutexLocker mu(Threads_lock);
3806 Threads::add(main_thread);
3807 }
3808
3809 // Any JVMTI raw monitors entered in onload will transition into
3810 // real raw monitor. VM is setup enough here for raw monitor enter.
3811 JvmtiExport::transition_pending_onload_raw_monitors();
3812
3813 // Create the VMThread
3814 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3815
3816 VMThread::create();
3817 Thread* vmthread = VMThread::vm_thread();
3818
3819 if (!os::create_thread(vmthread, os::vm_thread)) {
3820 vm_exit_during_initialization("Cannot create VM thread. "
3821 "Out of system resources.");
3822 }
3823
3824 // Wait for the VM thread to become ready, and VMThread::run to initialize
3825 // Monitors can have spurious returns, must always check another state flag
3826 {
3827 MutexLocker ml(Notify_lock);
3828 os::start_thread(vmthread);
3829 while (vmthread->active_handles() == NULL) {
3830 Notify_lock->wait();
3831 }
3832 }
3833 }
3834
3835 assert(Universe::is_fully_initialized(), "not initialized");
3836 if (VerifyDuringStartup) {
3837 // Make sure we're starting with a clean slate.
3838 VM_Verify verify_op;
3839 VMThread::execute(&verify_op);
3840 }
3841
3842 // We need this to update the java.vm.info property in case any flags used
3843 // to initially define it have been changed. This is needed for both CDS and
3844 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info
3845 // is initially computed. See Abstract_VM_Version::vm_info_string().
3846 // This update must happen before we initialize the java classes, but
3847 // after any initialization logic that might modify the flags.
3848 Arguments::update_vm_info_property(VM_Version::vm_info_string());
3849
3850 Thread* THREAD = Thread::current();
3851
3852 // Always call even when there are not JVMTI environments yet, since environments
3853 // may be attached late and JVMTI must track phases of VM execution
3854 JvmtiExport::enter_early_start_phase();
3855
3856 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3857 JvmtiExport::post_early_vm_start();
3858
3859 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3860
3861 quicken_jni_functions();
3862
3863 // No more stub generation allowed after that point.
3864 StubCodeDesc::freeze();
3865
3866 // Set flag that basic initialization has completed. Used by exceptions and various
3867 // debug stuff, that does not work until all basic classes have been initialized.
3868 set_init_completed();
3869
3870 LogConfiguration::post_initialize();
3871 Metaspace::post_initialize();
3872
3873 HOTSPOT_VM_INIT_END();
3874
3875 // record VM initialization completion time
3876 #if INCLUDE_MANAGEMENT
3877 Management::record_vm_init_completed();
3878 #endif // INCLUDE_MANAGEMENT
3879
3880 // Signal Dispatcher needs to be started before VMInit event is posted
3881 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3882
3883 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3884 if (!DisableAttachMechanism) {
3885 AttachListener::vm_start();
3886 if (StartAttachListener || AttachListener::init_at_startup()) {
3887 AttachListener::init();
3888 }
3889 }
3890
3891 // Launch -Xrun agents
3892 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3893 // back-end can launch with -Xdebug -Xrunjdwp.
3894 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3895 create_vm_init_libraries();
3896 }
3897
3898 if (CleanChunkPoolAsync) {
3899 Chunk::start_chunk_pool_cleaner_task();
3900 }
3901
3902 // initialize compiler(s)
3903 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3904 #if INCLUDE_JVMCI
3905 bool force_JVMCI_intialization = false;
3906 if (EnableJVMCI) {
3907 // Initialize JVMCI eagerly when it is explicitly requested.
3908 // Or when JVMCIPrintProperties is enabled.
3909 // The JVMCI Java initialization code will read this flag and
3910 // do the printing if it's set.
3911 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties;
3912
3913 if (!force_JVMCI_intialization) {
3914 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3915 // compilations via JVMCI will not actually block until JVMCI is initialized.
3916 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3917 }
3918 }
3919 #endif
3920 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
3921 // Postpone completion of compiler initialization to after JVMCI
3922 // is initialized to avoid timeouts of blocking compilations.
3923 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
3924 CompileBroker::compilation_init_phase2();
3925 }
3926 #endif
3927
3928 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3929 // It is done after compilers are initialized, because otherwise compilations of
3930 // signature polymorphic MH intrinsics can be missed
3931 // (see SystemDictionary::find_method_handle_intrinsic).
3932 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3933
3934 // This will initialize the module system. Only java.base classes can be
3935 // loaded until phase 2 completes
3936 call_initPhase2(CHECK_JNI_ERR);
3937
3938 // Always call even when there are not JVMTI environments yet, since environments
3939 // may be attached late and JVMTI must track phases of VM execution
3940 JvmtiExport::enter_start_phase();
3941
3942 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3943 JvmtiExport::post_vm_start();
3944
3945 // Final system initialization including security manager and system class loader
3946 call_initPhase3(CHECK_JNI_ERR);
3947
3948 // cache the system and platform class loaders
3949 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
3950
3951 #if INCLUDE_CDS
3952 if (DumpSharedSpaces) {
3953 // capture the module path info from the ModuleEntryTable
3954 ClassLoader::initialize_module_path(THREAD);
3955 }
3956 #endif
3957
3958 #if INCLUDE_JVMCI
3959 if (force_JVMCI_intialization) {
3960 JVMCIRuntime::force_initialization(CHECK_JNI_ERR);
3961 CompileBroker::compilation_init_phase2();
3962 }
3963 #endif
3964
3965 // Always call even when there are not JVMTI environments yet, since environments
3966 // may be attached late and JVMTI must track phases of VM execution
3967 JvmtiExport::enter_live_phase();
3968
3969 // Make perfmemory accessible
3970 PerfMemory::set_accessible(true);
3971
3972 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3973 JvmtiExport::post_vm_initialized();
3974
3975 JFR_ONLY(Jfr::on_vm_start();)
3976
3977 #if INCLUDE_MANAGEMENT
3978 Management::initialize(THREAD);
3979
3980 if (HAS_PENDING_EXCEPTION) {
3981 // management agent fails to start possibly due to
3982 // configuration problem and is responsible for printing
3983 // stack trace if appropriate. Simply exit VM.
3984 vm_exit(1);
3985 }
3986 #endif // INCLUDE_MANAGEMENT
3987
3988 if (MemProfiling) MemProfiler::engage();
3989 StatSampler::engage();
3990 if (CheckJNICalls) JniPeriodicChecker::engage();
3991
3992 BiasedLocking::init();
3993
3994 #if INCLUDE_RTM_OPT
3995 RTMLockingCounters::init();
3996 #endif
3997
3998 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3999 call_postVMInitHook(THREAD);
4000 // The Java side of PostVMInitHook.run must deal with all
4001 // exceptions and provide means of diagnosis.
4002 if (HAS_PENDING_EXCEPTION) {
4003 CLEAR_PENDING_EXCEPTION;
4004 }
4005 }
4006
4007 {
4008 MutexLocker ml(PeriodicTask_lock);
4009 // Make sure the WatcherThread can be started by WatcherThread::start()
4010 // or by dynamic enrollment.
4011 WatcherThread::make_startable();
4012 // Start up the WatcherThread if there are any periodic tasks
4013 // NOTE: All PeriodicTasks should be registered by now. If they
4014 // aren't, late joiners might appear to start slowly (we might
4015 // take a while to process their first tick).
4016 if (PeriodicTask::num_tasks() > 0) {
4017 WatcherThread::start();
4018 }
4019 }
4020
4021 create_vm_timer.end();
4022 #ifdef ASSERT
4023 _vm_complete = true;
4024 #endif
4025
4026 if (DumpSharedSpaces) {
4027 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
4028 ShouldNotReachHere();
4029 }
4030
4031 return JNI_OK;
4032 }
4033
4034 // type for the Agent_OnLoad and JVM_OnLoad entry points
4035 extern "C" {
4036 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
4037 }
4038 // Find a command line agent library and return its entry point for
4039 // -agentlib: -agentpath: -Xrun
4040 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
4041 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
4042 const char *on_load_symbols[],
4043 size_t num_symbol_entries) {
4044 OnLoadEntry_t on_load_entry = NULL;
4045 void *library = NULL;
4046
4047 if (!agent->valid()) {
4048 char buffer[JVM_MAXPATHLEN];
4049 char ebuf[1024] = "";
4050 const char *name = agent->name();
4051 const char *msg = "Could not find agent library ";
4052
4053 // First check to see if agent is statically linked into executable
4054 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
4055 library = agent->os_lib();
4056 } else if (agent->is_absolute_path()) {
4057 library = os::dll_load(name, ebuf, sizeof ebuf);
4058 if (library == NULL) {
4059 const char *sub_msg = " in absolute path, with error: ";
4060 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4061 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4062 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4063 // If we can't find the agent, exit.
4064 vm_exit_during_initialization(buf, NULL);
4065 FREE_C_HEAP_ARRAY(char, buf);
4066 }
4067 } else {
4068 // Try to load the agent from the standard dll directory
4069 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4070 name)) {
4071 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4072 }
4073 if (library == NULL) { // Try the library path directory.
4074 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4075 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4076 }
4077 if (library == NULL) {
4078 const char *sub_msg = " on the library path, with error: ";
4079 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4080
4081 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4082 strlen(ebuf) + strlen(sub_msg2) + 1;
4083 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4084 if (!agent->is_instrument_lib()) {
4085 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4086 } else {
4087 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4088 }
4089 // If we can't find the agent, exit.
4090 vm_exit_during_initialization(buf, NULL);
4091 FREE_C_HEAP_ARRAY(char, buf);
4092 }
4093 }
4094 }
4095 agent->set_os_lib(library);
4096 agent->set_valid();
4097 }
4098
4099 // Find the OnLoad function.
4100 on_load_entry =
4101 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4102 false,
4103 on_load_symbols,
4104 num_symbol_entries));
4105 return on_load_entry;
4106 }
4107
4108 // Find the JVM_OnLoad entry point
4109 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4110 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4111 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4112 }
4113
4114 // Find the Agent_OnLoad entry point
4115 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4116 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4117 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4118 }
4119
4120 // For backwards compatibility with -Xrun
4121 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4122 // treated like -agentpath:
4123 // Must be called before agent libraries are created
4124 void Threads::convert_vm_init_libraries_to_agents() {
4125 AgentLibrary* agent;
4126 AgentLibrary* next;
4127
4128 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4129 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4130 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4131
4132 // If there is an JVM_OnLoad function it will get called later,
4133 // otherwise see if there is an Agent_OnLoad
4134 if (on_load_entry == NULL) {
4135 on_load_entry = lookup_agent_on_load(agent);
4136 if (on_load_entry != NULL) {
4137 // switch it to the agent list -- so that Agent_OnLoad will be called,
4138 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4139 Arguments::convert_library_to_agent(agent);
4140 } else {
4141 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4142 }
4143 }
4144 }
4145 }
4146
4147 // Create agents for -agentlib: -agentpath: and converted -Xrun
4148 // Invokes Agent_OnLoad
4149 // Called very early -- before JavaThreads exist
4150 void Threads::create_vm_init_agents() {
4151 extern struct JavaVM_ main_vm;
4152 AgentLibrary* agent;
4153
4154 JvmtiExport::enter_onload_phase();
4155
4156 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4157 // CDS dumping does not support native JVMTI agent.
4158 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
4159 if (DumpSharedSpaces) {
4160 if(!agent->is_instrument_lib()) {
4161 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
4162 } else if (!AllowArchivingWithJavaAgent) {
4163 vm_exit_during_cds_dumping(
4164 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
4165 }
4166 }
4167
4168 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4169
4170 if (on_load_entry != NULL) {
4171 // Invoke the Agent_OnLoad function
4172 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4173 if (err != JNI_OK) {
4174 vm_exit_during_initialization("agent library failed to init", agent->name());
4175 }
4176 } else {
4177 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4178 }
4179 }
4180
4181 JvmtiExport::enter_primordial_phase();
4182 }
4183
4184 extern "C" {
4185 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4186 }
4187
4188 void Threads::shutdown_vm_agents() {
4189 // Send any Agent_OnUnload notifications
4190 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4191 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4192 extern struct JavaVM_ main_vm;
4193 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4194
4195 // Find the Agent_OnUnload function.
4196 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4197 os::find_agent_function(agent,
4198 false,
4199 on_unload_symbols,
4200 num_symbol_entries));
4201
4202 // Invoke the Agent_OnUnload function
4203 if (unload_entry != NULL) {
4204 JavaThread* thread = JavaThread::current();
4205 ThreadToNativeFromVM ttn(thread);
4206 HandleMark hm(thread);
4207 (*unload_entry)(&main_vm);
4208 }
4209 }
4210 }
4211
4212 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4213 // Invokes JVM_OnLoad
4214 void Threads::create_vm_init_libraries() {
4215 extern struct JavaVM_ main_vm;
4216 AgentLibrary* agent;
4217
4218 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4219 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4220
4221 if (on_load_entry != NULL) {
4222 // Invoke the JVM_OnLoad function
4223 JavaThread* thread = JavaThread::current();
4224 ThreadToNativeFromVM ttn(thread);
4225 HandleMark hm(thread);
4226 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4227 if (err != JNI_OK) {
4228 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4229 }
4230 } else {
4231 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4232 }
4233 }
4234 }
4235
4236
4237 // Last thread running calls java.lang.Shutdown.shutdown()
4238 void JavaThread::invoke_shutdown_hooks() {
4239 HandleMark hm(this);
4240
4241 // We could get here with a pending exception, if so clear it now.
4242 if (this->has_pending_exception()) {
4243 this->clear_pending_exception();
4244 }
4245
4246 EXCEPTION_MARK;
4247 Klass* shutdown_klass =
4248 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4249 THREAD);
4250 if (shutdown_klass != NULL) {
4251 // SystemDictionary::resolve_or_null will return null if there was
4252 // an exception. If we cannot load the Shutdown class, just don't
4253 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4254 // won't be run. Note that if a shutdown hook was registered,
4255 // the Shutdown class would have already been loaded
4256 // (Runtime.addShutdownHook will load it).
4257 JavaValue result(T_VOID);
4258 JavaCalls::call_static(&result,
4259 shutdown_klass,
4260 vmSymbols::shutdown_method_name(),
4261 vmSymbols::void_method_signature(),
4262 THREAD);
4263 }
4264 CLEAR_PENDING_EXCEPTION;
4265 }
4266
4267 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4268 // the program falls off the end of main(). Another VM exit path is through
4269 // vm_exit() when the program calls System.exit() to return a value or when
4270 // there is a serious error in VM. The two shutdown paths are not exactly
4271 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4272 // and VM_Exit op at VM level.
4273 //
4274 // Shutdown sequence:
4275 // + Shutdown native memory tracking if it is on
4276 // + Wait until we are the last non-daemon thread to execute
4277 // <-- every thing is still working at this moment -->
4278 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4279 // shutdown hooks
4280 // + Call before_exit(), prepare for VM exit
4281 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4282 // currently the only user of this mechanism is File.deleteOnExit())
4283 // > stop StatSampler, watcher thread, CMS threads,
4284 // post thread end and vm death events to JVMTI,
4285 // stop signal thread
4286 // + Call JavaThread::exit(), it will:
4287 // > release JNI handle blocks, remove stack guard pages
4288 // > remove this thread from Threads list
4289 // <-- no more Java code from this thread after this point -->
4290 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4291 // the compiler threads at safepoint
4292 // <-- do not use anything that could get blocked by Safepoint -->
4293 // + Disable tracing at JNI/JVM barriers
4294 // + Set _vm_exited flag for threads that are still running native code
4295 // + Call exit_globals()
4296 // > deletes tty
4297 // > deletes PerfMemory resources
4298 // + Delete this thread
4299 // + Return to caller
4300
4301 bool Threads::destroy_vm() {
4302 JavaThread* thread = JavaThread::current();
4303
4304 #ifdef ASSERT
4305 _vm_complete = false;
4306 #endif
4307 // Wait until we are the last non-daemon thread to execute
4308 { MutexLocker nu(Threads_lock);
4309 while (Threads::number_of_non_daemon_threads() > 1)
4310 // This wait should make safepoint checks, wait without a timeout,
4311 // and wait as a suspend-equivalent condition.
4312 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4313 Mutex::_as_suspend_equivalent_flag);
4314 }
4315
4316 EventShutdown e;
4317 if (e.should_commit()) {
4318 e.set_reason("No remaining non-daemon Java threads");
4319 e.commit();
4320 }
4321
4322 // Hang forever on exit if we are reporting an error.
4323 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4324 os::infinite_sleep();
4325 }
4326 os::wait_for_keypress_at_exit();
4327
4328 // run Java level shutdown hooks
4329 thread->invoke_shutdown_hooks();
4330
4331 before_exit(thread);
4332
4333 thread->exit(true);
4334
4335 // Stop VM thread.
4336 {
4337 // 4945125 The vm thread comes to a safepoint during exit.
4338 // GC vm_operations can get caught at the safepoint, and the
4339 // heap is unparseable if they are caught. Grab the Heap_lock
4340 // to prevent this. The GC vm_operations will not be able to
4341 // queue until after the vm thread is dead. After this point,
4342 // we'll never emerge out of the safepoint before the VM exits.
4343
4344 MutexLockerEx ml(Heap_lock, Mutex::_no_safepoint_check_flag);
4345
4346 VMThread::wait_for_vm_thread_exit();
4347 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4348 VMThread::destroy();
4349 }
4350
4351 // Now, all Java threads are gone except daemon threads. Daemon threads
4352 // running Java code or in VM are stopped by the Safepoint. However,
4353 // daemon threads executing native code are still running. But they
4354 // will be stopped at native=>Java/VM barriers. Note that we can't
4355 // simply kill or suspend them, as it is inherently deadlock-prone.
4356
4357 VM_Exit::set_vm_exited();
4358
4359 // Clean up ideal graph printers after the VMThread has started
4360 // the final safepoint which will block all the Compiler threads.
4361 // Note that this Thread has already logically exited so the
4362 // clean_up() function's use of a JavaThreadIteratorWithHandle
4363 // would be a problem except set_vm_exited() has remembered the
4364 // shutdown thread which is granted a policy exception.
4365 #if defined(COMPILER2) && !defined(PRODUCT)
4366 IdealGraphPrinter::clean_up();
4367 #endif
4368
4369 notify_vm_shutdown();
4370
4371 // exit_globals() will delete tty
4372 exit_globals();
4373
4374 // We are after VM_Exit::set_vm_exited() so we can't call
4375 // thread->smr_delete() or we will block on the Threads_lock.
4376 // Deleting the shutdown thread here is safe because another
4377 // JavaThread cannot have an active ThreadsListHandle for
4378 // this JavaThread.
4379 delete thread;
4380
4381 #if INCLUDE_JVMCI
4382 if (JVMCICounterSize > 0) {
4383 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4384 }
4385 #endif
4386
4387 LogConfiguration::finalize();
4388
4389 return true;
4390 }
4391
4392
4393 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4394 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4395 return is_supported_jni_version(version);
4396 }
4397
4398
4399 jboolean Threads::is_supported_jni_version(jint version) {
4400 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4401 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4402 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4403 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4404 if (version == JNI_VERSION_9) return JNI_TRUE;
4405 if (version == JNI_VERSION_10) return JNI_TRUE;
4406 return JNI_FALSE;
4407 }
4408
4409
4410 void Threads::add(JavaThread* p, bool force_daemon) {
4411 // The threads lock must be owned at this point
4412 assert(Threads_lock->owned_by_self(), "must have threads lock");
4413
4414 BarrierSet::barrier_set()->on_thread_attach(p);
4415
4416 p->set_next(_thread_list);
4417 _thread_list = p;
4418
4419 // Once a JavaThread is added to the Threads list, smr_delete() has
4420 // to be used to delete it. Otherwise we can just delete it directly.
4421 p->set_on_thread_list();
4422
4423 _number_of_threads++;
4424 oop threadObj = p->threadObj();
4425 bool daemon = true;
4426 // Bootstrapping problem: threadObj can be null for initial
4427 // JavaThread (or for threads attached via JNI)
4428 if ((!force_daemon) && !is_daemon((threadObj))) {
4429 _number_of_non_daemon_threads++;
4430 daemon = false;
4431 }
4432
4433 ThreadService::add_thread(p, daemon);
4434
4435 // Maintain fast thread list
4436 ThreadsSMRSupport::add_thread(p);
4437
4438 // Possible GC point.
4439 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4440 }
4441
4442 void Threads::remove(JavaThread* p) {
4443
4444 // Reclaim the objectmonitors from the omInUseList and omFreeList of the moribund thread.
4445 ObjectSynchronizer::omFlush(p);
4446
4447 // Extra scope needed for Thread_lock, so we can check
4448 // that we do not remove thread without safepoint code notice
4449 { MutexLocker ml(Threads_lock);
4450
4451 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4452
4453 // Maintain fast thread list
4454 ThreadsSMRSupport::remove_thread(p);
4455
4456 JavaThread* current = _thread_list;
4457 JavaThread* prev = NULL;
4458
4459 while (current != p) {
4460 prev = current;
4461 current = current->next();
4462 }
4463
4464 if (prev) {
4465 prev->set_next(current->next());
4466 } else {
4467 _thread_list = p->next();
4468 }
4469
4470 _number_of_threads--;
4471 oop threadObj = p->threadObj();
4472 bool daemon = true;
4473 if (!is_daemon(threadObj)) {
4474 _number_of_non_daemon_threads--;
4475 daemon = false;
4476
4477 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4478 // on destroy_vm will wake up.
4479 if (number_of_non_daemon_threads() == 1) {
4480 Threads_lock->notify_all();
4481 }
4482 }
4483 ThreadService::remove_thread(p, daemon);
4484
4485 // Make sure that safepoint code disregard this thread. This is needed since
4486 // the thread might mess around with locks after this point. This can cause it
4487 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4488 // of this thread since it is removed from the queue.
4489 p->set_terminated_value();
4490 } // unlock Threads_lock
4491
4492 // Since Events::log uses a lock, we grab it outside the Threads_lock
4493 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4494 }
4495
4496 // Operations on the Threads list for GC. These are not explicitly locked,
4497 // but the garbage collector must provide a safe context for them to run.
4498 // In particular, these things should never be called when the Threads_lock
4499 // is held by some other thread. (Note: the Safepoint abstraction also
4500 // uses the Threads_lock to guarantee this property. It also makes sure that
4501 // all threads gets blocked when exiting or starting).
4502
4503 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4504 ALL_JAVA_THREADS(p) {
4505 p->oops_do(f, cf);
4506 }
4507 VMThread::vm_thread()->oops_do(f, cf);
4508 }
4509
4510 void Threads::change_thread_claim_parity() {
4511 // Set the new claim parity.
4512 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4513 "Not in range.");
4514 _thread_claim_parity++;
4515 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4516 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4517 "Not in range.");
4518 }
4519
4520 #ifdef ASSERT
4521 void Threads::assert_all_threads_claimed() {
4522 ALL_JAVA_THREADS(p) {
4523 const int thread_parity = p->oops_do_parity();
4524 assert((thread_parity == _thread_claim_parity),
4525 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4526 }
4527 VMThread* vmt = VMThread::vm_thread();
4528 const int thread_parity = vmt->oops_do_parity();
4529 assert((thread_parity == _thread_claim_parity),
4530 "VMThread " PTR_FORMAT " has incorrect parity %d != %d", p2i(vmt), thread_parity, _thread_claim_parity);
4531 }
4532 #endif // ASSERT
4533
4534 class ParallelOopsDoThreadClosure : public ThreadClosure {
4535 private:
4536 OopClosure* _f;
4537 CodeBlobClosure* _cf;
4538 public:
4539 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4540 void do_thread(Thread* t) {
4541 t->oops_do(_f, _cf);
4542 }
4543 };
4544
4545 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4546 ParallelOopsDoThreadClosure tc(f, cf);
4547 possibly_parallel_threads_do(is_par, &tc);
4548 }
4549
4550 void Threads::nmethods_do(CodeBlobClosure* cf) {
4551 ALL_JAVA_THREADS(p) {
4552 // This is used by the code cache sweeper to mark nmethods that are active
4553 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4554 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4555 if(!p->is_Code_cache_sweeper_thread()) {
4556 p->nmethods_do(cf);
4557 }
4558 }
4559 }
4560
4561 void Threads::metadata_do(void f(Metadata*)) {
4562 ALL_JAVA_THREADS(p) {
4563 p->metadata_do(f);
4564 }
4565 }
4566
4567 class ThreadHandlesClosure : public ThreadClosure {
4568 void (*_f)(Metadata*);
4569 public:
4570 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4571 virtual void do_thread(Thread* thread) {
4572 thread->metadata_handles_do(_f);
4573 }
4574 };
4575
4576 void Threads::metadata_handles_do(void f(Metadata*)) {
4577 // Only walk the Handles in Thread.
4578 ThreadHandlesClosure handles_closure(f);
4579 threads_do(&handles_closure);
4580 }
4581
4582 void Threads::deoptimized_wrt_marked_nmethods() {
4583 ALL_JAVA_THREADS(p) {
4584 p->deoptimized_wrt_marked_nmethods();
4585 }
4586 }
4587
4588
4589 // Get count Java threads that are waiting to enter the specified monitor.
4590 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4591 int count,
4592 address monitor) {
4593 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4594
4595 int i = 0;
4596 DO_JAVA_THREADS(t_list, p) {
4597 if (!p->can_call_java()) continue;
4598
4599 address pending = (address)p->current_pending_monitor();
4600 if (pending == monitor) { // found a match
4601 if (i < count) result->append(p); // save the first count matches
4602 i++;
4603 }
4604 }
4605
4606 return result;
4607 }
4608
4609
4610 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4611 address owner) {
4612 // NULL owner means not locked so we can skip the search
4613 if (owner == NULL) return NULL;
4614
4615 DO_JAVA_THREADS(t_list, p) {
4616 // first, see if owner is the address of a Java thread
4617 if (owner == (address)p) return p;
4618 }
4619
4620 // Cannot assert on lack of success here since this function may be
4621 // used by code that is trying to report useful problem information
4622 // like deadlock detection.
4623 if (UseHeavyMonitors) return NULL;
4624
4625 // If we didn't find a matching Java thread and we didn't force use of
4626 // heavyweight monitors, then the owner is the stack address of the
4627 // Lock Word in the owning Java thread's stack.
4628 //
4629 JavaThread* the_owner = NULL;
4630 DO_JAVA_THREADS(t_list, q) {
4631 if (q->is_lock_owned(owner)) {
4632 the_owner = q;
4633 break;
4634 }
4635 }
4636
4637 // cannot assert on lack of success here; see above comment
4638 return the_owner;
4639 }
4640
4641 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4642 void Threads::print_on(outputStream* st, bool print_stacks,
4643 bool internal_format, bool print_concurrent_locks,
4644 bool print_extended_info) {
4645 char buf[32];
4646 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4647
4648 st->print_cr("Full thread dump %s (%s %s):",
4649 VM_Version::vm_name(),
4650 VM_Version::vm_release(),
4651 VM_Version::vm_info_string());
4652 st->cr();
4653
4654 #if INCLUDE_SERVICES
4655 // Dump concurrent locks
4656 ConcurrentLocksDump concurrent_locks;
4657 if (print_concurrent_locks) {
4658 concurrent_locks.dump_at_safepoint();
4659 }
4660 #endif // INCLUDE_SERVICES
4661
4662 ThreadsSMRSupport::print_info_on(st);
4663 st->cr();
4664
4665 ALL_JAVA_THREADS(p) {
4666 ResourceMark rm;
4667 p->print_on(st, print_extended_info);
4668 if (print_stacks) {
4669 if (internal_format) {
4670 p->trace_stack();
4671 } else {
4672 p->print_stack_on(st);
4673 }
4674 }
4675 st->cr();
4676 #if INCLUDE_SERVICES
4677 if (print_concurrent_locks) {
4678 concurrent_locks.print_locks_on(p, st);
4679 }
4680 #endif // INCLUDE_SERVICES
4681 }
4682
4683 VMThread::vm_thread()->print_on(st);
4684 st->cr();
4685 Universe::heap()->print_gc_threads_on(st);
4686 WatcherThread* wt = WatcherThread::watcher_thread();
4687 if (wt != NULL) {
4688 wt->print_on(st);
4689 st->cr();
4690 }
4691
4692 st->flush();
4693 }
4694
4695 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4696 int buflen, bool* found_current) {
4697 if (this_thread != NULL) {
4698 bool is_current = (current == this_thread);
4699 *found_current = *found_current || is_current;
4700 st->print("%s", is_current ? "=>" : " ");
4701
4702 st->print(PTR_FORMAT, p2i(this_thread));
4703 st->print(" ");
4704 this_thread->print_on_error(st, buf, buflen);
4705 st->cr();
4706 }
4707 }
4708
4709 class PrintOnErrorClosure : public ThreadClosure {
4710 outputStream* _st;
4711 Thread* _current;
4712 char* _buf;
4713 int _buflen;
4714 bool* _found_current;
4715 public:
4716 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4717 int buflen, bool* found_current) :
4718 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4719
4720 virtual void do_thread(Thread* thread) {
4721 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4722 }
4723 };
4724
4725 // Threads::print_on_error() is called by fatal error handler. It's possible
4726 // that VM is not at safepoint and/or current thread is inside signal handler.
4727 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4728 // memory (even in resource area), it might deadlock the error handler.
4729 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4730 int buflen) {
4731 ThreadsSMRSupport::print_info_on(st);
4732 st->cr();
4733
4734 bool found_current = false;
4735 st->print_cr("Java Threads: ( => current thread )");
4736 ALL_JAVA_THREADS(thread) {
4737 print_on_error(thread, st, current, buf, buflen, &found_current);
4738 }
4739 st->cr();
4740
4741 st->print_cr("Other Threads:");
4742 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4743 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4744
4745 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4746 Universe::heap()->gc_threads_do(&print_closure);
4747
4748 if (!found_current) {
4749 st->cr();
4750 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4751 current->print_on_error(st, buf, buflen);
4752 st->cr();
4753 }
4754 st->cr();
4755
4756 st->print_cr("Threads with active compile tasks:");
4757 print_threads_compiling(st, buf, buflen);
4758 }
4759
4760 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) {
4761 ALL_JAVA_THREADS(thread) {
4762 if (thread->is_Compiler_thread()) {
4763 CompilerThread* ct = (CompilerThread*) thread;
4764
4765 // Keep task in local variable for NULL check.
4766 // ct->_task might be set to NULL by concurring compiler thread
4767 // because it completed the compilation. The task is never freed,
4768 // though, just returned to a free list.
4769 CompileTask* task = ct->task();
4770 if (task != NULL) {
4771 thread->print_name_on_error(st, buf, buflen);
4772 st->print(" ");
4773 task->print(st, NULL, true, true);
4774 }
4775 }
4776 }
4777 }
4778
4779
4780 // Internal SpinLock and Mutex
4781 // Based on ParkEvent
4782
4783 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4784 //
4785 // We employ SpinLocks _only for low-contention, fixed-length
4786 // short-duration critical sections where we're concerned
4787 // about native mutex_t or HotSpot Mutex:: latency.
4788 // The mux construct provides a spin-then-block mutual exclusion
4789 // mechanism.
4790 //
4791 // Testing has shown that contention on the ListLock guarding gFreeList
4792 // is common. If we implement ListLock as a simple SpinLock it's common
4793 // for the JVM to devolve to yielding with little progress. This is true
4794 // despite the fact that the critical sections protected by ListLock are
4795 // extremely short.
4796 //
4797 // TODO-FIXME: ListLock should be of type SpinLock.
4798 // We should make this a 1st-class type, integrated into the lock
4799 // hierarchy as leaf-locks. Critically, the SpinLock structure
4800 // should have sufficient padding to avoid false-sharing and excessive
4801 // cache-coherency traffic.
4802
4803
4804 typedef volatile int SpinLockT;
4805
4806 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4807 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4808 return; // normal fast-path return
4809 }
4810
4811 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4812 int ctr = 0;
4813 int Yields = 0;
4814 for (;;) {
4815 while (*adr != 0) {
4816 ++ctr;
4817 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4818 if (Yields > 5) {
4819 os::naked_short_sleep(1);
4820 } else {
4821 os::naked_yield();
4822 ++Yields;
4823 }
4824 } else {
4825 SpinPause();
4826 }
4827 }
4828 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4829 }
4830 }
4831
4832 void Thread::SpinRelease(volatile int * adr) {
4833 assert(*adr != 0, "invariant");
4834 OrderAccess::fence(); // guarantee at least release consistency.
4835 // Roach-motel semantics.
4836 // It's safe if subsequent LDs and STs float "up" into the critical section,
4837 // but prior LDs and STs within the critical section can't be allowed
4838 // to reorder or float past the ST that releases the lock.
4839 // Loads and stores in the critical section - which appear in program
4840 // order before the store that releases the lock - must also appear
4841 // before the store that releases the lock in memory visibility order.
4842 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4843 // the ST of 0 into the lock-word which releases the lock, so fence
4844 // more than covers this on all platforms.
4845 *adr = 0;
4846 }
4847
4848 // muxAcquire and muxRelease:
4849 //
4850 // * muxAcquire and muxRelease support a single-word lock-word construct.
4851 // The LSB of the word is set IFF the lock is held.
4852 // The remainder of the word points to the head of a singly-linked list
4853 // of threads blocked on the lock.
4854 //
4855 // * The current implementation of muxAcquire-muxRelease uses its own
4856 // dedicated Thread._MuxEvent instance. If we're interested in
4857 // minimizing the peak number of extant ParkEvent instances then
4858 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4859 // as certain invariants were satisfied. Specifically, care would need
4860 // to be taken with regards to consuming unpark() "permits".
4861 // A safe rule of thumb is that a thread would never call muxAcquire()
4862 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4863 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4864 // consume an unpark() permit intended for monitorenter, for instance.
4865 // One way around this would be to widen the restricted-range semaphore
4866 // implemented in park(). Another alternative would be to provide
4867 // multiple instances of the PlatformEvent() for each thread. One
4868 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4869 //
4870 // * Usage:
4871 // -- Only as leaf locks
4872 // -- for short-term locking only as muxAcquire does not perform
4873 // thread state transitions.
4874 //
4875 // Alternatives:
4876 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4877 // but with parking or spin-then-park instead of pure spinning.
4878 // * Use Taura-Oyama-Yonenzawa locks.
4879 // * It's possible to construct a 1-0 lock if we encode the lockword as
4880 // (List,LockByte). Acquire will CAS the full lockword while Release
4881 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4882 // acquiring threads use timers (ParkTimed) to detect and recover from
4883 // the stranding window. Thread/Node structures must be aligned on 256-byte
4884 // boundaries by using placement-new.
4885 // * Augment MCS with advisory back-link fields maintained with CAS().
4886 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4887 // The validity of the backlinks must be ratified before we trust the value.
4888 // If the backlinks are invalid the exiting thread must back-track through the
4889 // the forward links, which are always trustworthy.
4890 // * Add a successor indication. The LockWord is currently encoded as
4891 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4892 // to provide the usual futile-wakeup optimization.
4893 // See RTStt for details.
4894 //
4895
4896
4897 const intptr_t LOCKBIT = 1;
4898
4899 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4900 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4901 if (w == 0) return;
4902 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4903 return;
4904 }
4905
4906 ParkEvent * const Self = Thread::current()->_MuxEvent;
4907 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4908 for (;;) {
4909 int its = (os::is_MP() ? 100 : 0) + 1;
4910
4911 // Optional spin phase: spin-then-park strategy
4912 while (--its >= 0) {
4913 w = *Lock;
4914 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4915 return;
4916 }
4917 }
4918
4919 Self->reset();
4920 Self->OnList = intptr_t(Lock);
4921 // The following fence() isn't _strictly necessary as the subsequent
4922 // CAS() both serializes execution and ratifies the fetched *Lock value.
4923 OrderAccess::fence();
4924 for (;;) {
4925 w = *Lock;
4926 if ((w & LOCKBIT) == 0) {
4927 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4928 Self->OnList = 0; // hygiene - allows stronger asserts
4929 return;
4930 }
4931 continue; // Interference -- *Lock changed -- Just retry
4932 }
4933 assert(w & LOCKBIT, "invariant");
4934 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4935 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4936 }
4937
4938 while (Self->OnList != 0) {
4939 Self->park();
4940 }
4941 }
4942 }
4943
4944 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4945 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4946 if (w == 0) return;
4947 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4948 return;
4949 }
4950
4951 ParkEvent * ReleaseAfter = NULL;
4952 if (ev == NULL) {
4953 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4954 }
4955 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4956 for (;;) {
4957 guarantee(ev->OnList == 0, "invariant");
4958 int its = (os::is_MP() ? 100 : 0) + 1;
4959
4960 // Optional spin phase: spin-then-park strategy
4961 while (--its >= 0) {
4962 w = *Lock;
4963 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4964 if (ReleaseAfter != NULL) {
4965 ParkEvent::Release(ReleaseAfter);
4966 }
4967 return;
4968 }
4969 }
4970
4971 ev->reset();
4972 ev->OnList = intptr_t(Lock);
4973 // The following fence() isn't _strictly necessary as the subsequent
4974 // CAS() both serializes execution and ratifies the fetched *Lock value.
4975 OrderAccess::fence();
4976 for (;;) {
4977 w = *Lock;
4978 if ((w & LOCKBIT) == 0) {
4979 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4980 ev->OnList = 0;
4981 // We call ::Release while holding the outer lock, thus
4982 // artificially lengthening the critical section.
4983 // Consider deferring the ::Release() until the subsequent unlock(),
4984 // after we've dropped the outer lock.
4985 if (ReleaseAfter != NULL) {
4986 ParkEvent::Release(ReleaseAfter);
4987 }
4988 return;
4989 }
4990 continue; // Interference -- *Lock changed -- Just retry
4991 }
4992 assert(w & LOCKBIT, "invariant");
4993 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4994 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4995 }
4996
4997 while (ev->OnList != 0) {
4998 ev->park();
4999 }
5000 }
5001 }
5002
5003 // Release() must extract a successor from the list and then wake that thread.
5004 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
5005 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
5006 // Release() would :
5007 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
5008 // (B) Extract a successor from the private list "in-hand"
5009 // (C) attempt to CAS() the residual back into *Lock over null.
5010 // If there were any newly arrived threads and the CAS() would fail.
5011 // In that case Release() would detach the RATs, re-merge the list in-hand
5012 // with the RATs and repeat as needed. Alternately, Release() might
5013 // detach and extract a successor, but then pass the residual list to the wakee.
5014 // The wakee would be responsible for reattaching and remerging before it
5015 // competed for the lock.
5016 //
5017 // Both "pop" and DMR are immune from ABA corruption -- there can be
5018 // multiple concurrent pushers, but only one popper or detacher.
5019 // This implementation pops from the head of the list. This is unfair,
5020 // but tends to provide excellent throughput as hot threads remain hot.
5021 // (We wake recently run threads first).
5022 //
5023 // All paths through muxRelease() will execute a CAS.
5024 // Release consistency -- We depend on the CAS in muxRelease() to provide full
5025 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
5026 // executed within the critical section are complete and globally visible before the
5027 // store (CAS) to the lock-word that releases the lock becomes globally visible.
5028 void Thread::muxRelease(volatile intptr_t * Lock) {
5029 for (;;) {
5030 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
5031 assert(w & LOCKBIT, "invariant");
5032 if (w == LOCKBIT) return;
5033 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
5034 assert(List != NULL, "invariant");
5035 assert(List->OnList == intptr_t(Lock), "invariant");
5036 ParkEvent * const nxt = List->ListNext;
5037 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5038
5039 // The following CAS() releases the lock and pops the head element.
5040 // The CAS() also ratifies the previously fetched lock-word value.
5041 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
5042 continue;
5043 }
5044 List->OnList = 0;
5045 OrderAccess::fence();
5046 List->unpark();
5047 return;
5048 }
5049 }
5050
5051
5052 void Threads::verify() {
5053 ALL_JAVA_THREADS(p) {
5054 p->verify();
5055 }
5056 VMThread* thread = VMThread::vm_thread();
5057 if (thread != NULL) thread->verify();
5058 }