1 /*
2 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "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/handles.inline.hpp"
73 #include "runtime/handshake.hpp"
74 #include "runtime/init.hpp"
75 #include "runtime/interfaceSupport.inline.hpp"
76 #include "runtime/java.hpp"
77 #include "runtime/javaCalls.hpp"
78 #include "runtime/jniHandles.inline.hpp"
79 #include "runtime/jniPeriodicChecker.hpp"
80 #include "runtime/memprofiler.hpp"
81 #include "runtime/mutexLocker.hpp"
82 #include "runtime/objectMonitor.hpp"
83 #include "runtime/orderAccess.hpp"
84 #include "runtime/osThread.hpp"
85 #include "runtime/prefetch.inline.hpp"
86 #include "runtime/safepoint.hpp"
87 #include "runtime/safepointMechanism.inline.hpp"
88 #include "runtime/safepointVerifiers.hpp"
89 #include "runtime/sharedRuntime.hpp"
90 #include "runtime/statSampler.hpp"
91 #include "runtime/stubRoutines.hpp"
92 #include "runtime/sweeper.hpp"
93 #include "runtime/task.hpp"
94 #include "runtime/thread.inline.hpp"
95 #include "runtime/threadCritical.hpp"
96 #include "runtime/threadSMR.inline.hpp"
97 #include "runtime/threadStatisticalInfo.hpp"
98 #include "runtime/timer.hpp"
99 #include "runtime/timerTrace.hpp"
100 #include "runtime/vframe.inline.hpp"
101 #include "runtime/vframeArray.hpp"
102 #include "runtime/vframe_hp.hpp"
103 #include "runtime/vmThread.hpp"
104 #include "runtime/vmOperations.hpp"
105 #include "runtime/vm_version.hpp"
106 #include "services/attachListener.hpp"
107 #include "services/management.hpp"
108 #include "services/memTracker.hpp"
109 #include "services/threadService.hpp"
110 #include "utilities/align.hpp"
111 #include "utilities/copy.hpp"
112 #include "utilities/defaultStream.hpp"
113 #include "utilities/dtrace.hpp"
114 #include "utilities/events.hpp"
115 #include "utilities/macros.hpp"
116 #include "utilities/preserveException.hpp"
117 #include "utilities/singleWriterSynchronizer.hpp"
118 #include "utilities/vmError.hpp"
119 #if INCLUDE_JVMCI
120 #include "jvmci/jvmciCompiler.hpp"
121 #include "jvmci/jvmciRuntime.hpp"
122 #include "logging/logHandle.hpp"
123 #endif
124 #ifdef COMPILER1
125 #include "c1/c1_Compiler.hpp"
126 #endif
127 #ifdef COMPILER2
128 #include "opto/c2compiler.hpp"
129 #include "opto/idealGraphPrinter.hpp"
130 #endif
131 #if INCLUDE_RTM_OPT
132 #include "runtime/rtmLocking.hpp"
133 #endif
134 #if INCLUDE_JFR
135 #include "jfr/jfr.hpp"
136 #endif
137
138 // Initialization after module runtime initialization
139 void universe_post_module_init(); // must happen after call_initPhase2
140
141 #ifdef DTRACE_ENABLED
142
143 // Only bother with this argument setup if dtrace is available
144
145 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
146 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
147
148 #define DTRACE_THREAD_PROBE(probe, javathread) \
149 { \
150 ResourceMark rm(this); \
151 int len = 0; \
152 const char* name = (javathread)->get_thread_name(); \
153 len = strlen(name); \
154 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
155 (char *) name, len, \
156 java_lang_Thread::thread_id((javathread)->threadObj()), \
157 (uintptr_t) (javathread)->osthread()->thread_id(), \
158 java_lang_Thread::is_daemon((javathread)->threadObj())); \
159 }
160
161 #else // ndef DTRACE_ENABLED
162
163 #define DTRACE_THREAD_PROBE(probe, javathread)
164
165 #endif // ndef DTRACE_ENABLED
166
167 #ifndef USE_LIBRARY_BASED_TLS_ONLY
168 // Current thread is maintained as a thread-local variable
169 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
170 #endif
171
172 // ======= Thread ========
173 // Support for forcing alignment of thread objects for biased locking
174 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
175 if (UseBiasedLocking) {
176 const int alignment = markOopDesc::biased_lock_alignment;
177 size_t aligned_size = size + (alignment - sizeof(intptr_t));
178 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
179 : AllocateHeap(aligned_size, flags, CURRENT_PC,
180 AllocFailStrategy::RETURN_NULL);
181 void* aligned_addr = align_up(real_malloc_addr, alignment);
182 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
183 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
184 "JavaThread alignment code overflowed allocated storage");
185 if (aligned_addr != real_malloc_addr) {
186 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
187 p2i(real_malloc_addr),
188 p2i(aligned_addr));
189 }
190 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
191 return aligned_addr;
192 } else {
193 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
194 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
195 }
196 }
197
198 void Thread::operator delete(void* p) {
199 if (UseBiasedLocking) {
200 FreeHeap(((Thread*) p)->_real_malloc_address);
201 } else {
202 FreeHeap(p);
203 }
204 }
205
206 void JavaThread::smr_delete() {
207 if (_on_thread_list) {
208 ThreadsSMRSupport::smr_delete(this);
209 } else {
210 delete this;
211 }
212 }
213
214 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
215 // JavaThread
216
217 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
218
219 Thread::Thread() {
220
221 DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
222
223 // stack and get_thread
224 set_stack_base(NULL);
225 set_stack_size(0);
226 set_self_raw_id(0);
227 set_lgrp_id(-1);
228 DEBUG_ONLY(clear_suspendible_thread();)
229
230 // allocated data structures
231 set_osthread(NULL);
232 set_resource_area(new (mtThread)ResourceArea());
233 DEBUG_ONLY(_current_resource_mark = NULL;)
234 set_handle_area(new (mtThread) HandleArea(NULL));
235 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
236 set_active_handles(NULL);
237 set_free_handle_block(NULL);
238 set_last_handle_mark(NULL);
239 DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
240
241 // This initial value ==> never claimed.
242 _oops_do_parity = 0;
243 _threads_hazard_ptr = NULL;
244 _threads_list_ptr = NULL;
245 _nested_threads_hazard_ptr_cnt = 0;
246 _rcu_counter = 0;
247
248 // the handle mark links itself to last_handle_mark
249 new HandleMark(this);
250
251 // plain initialization
252 debug_only(_owned_locks = NULL;)
253 debug_only(_allow_allocation_count = 0;)
254 NOT_PRODUCT(_allow_safepoint_count = 0;)
255 NOT_PRODUCT(_skip_gcalot = false;)
256 _jvmti_env_iteration_count = 0;
257 set_allocated_bytes(0);
258 _vm_operation_started_count = 0;
259 _vm_operation_completed_count = 0;
260 _current_pending_monitor = NULL;
261 _current_pending_monitor_is_from_java = true;
262 _current_waiting_monitor = NULL;
263 _num_nested_signal = 0;
264 omFreeList = NULL;
265 omFreeCount = 0;
266 omFreeProvision = 32;
267 omInUseList = NULL;
268 omInUseCount = 0;
269
270 #ifdef ASSERT
271 _visited_for_critical_count = false;
272 #endif
273
274 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
275 Monitor::_safepoint_check_sometimes);
276 _suspend_flags = 0;
277
278 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
279 _hashStateX = os::random();
280 _hashStateY = 842502087;
281 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
282 _hashStateW = 273326509;
283
284 _OnTrap = 0;
285 _Stalled = 0;
286 _TypeTag = 0x2BAD;
287
288 // Many of the following fields are effectively final - immutable
289 // Note that nascent threads can't use the Native Monitor-Mutex
290 // construct until the _MutexEvent is initialized ...
291 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
292 // we might instead use a stack of ParkEvents that we could provision on-demand.
293 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
294 // and ::Release()
295 _ParkEvent = ParkEvent::Allocate(this);
296 _SleepEvent = 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(_MuxEvent); _MuxEvent = NULL;
463
464 delete handle_area();
465 delete metadata_handles();
466
467 // SR_handler uses this as a termination indicator -
468 // needs to happen before os::free_thread()
469 delete _SR_lock;
470 _SR_lock = NULL;
471
472 // osthread() can be NULL, if creation of thread failed.
473 if (osthread() != NULL) os::free_thread(osthread());
474
475 // Clear Thread::current if thread is deleting itself and it has not
476 // already been done. This must be done before the memory is deallocated.
477 // Needed to ensure JNI correctly detects non-attached threads.
478 if (this == Thread::current_or_null()) {
479 Thread::clear_thread_current();
480 }
481
482 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
483 }
484
485 #ifdef ASSERT
486 // A JavaThread is considered "dangling" if it is not the current
487 // thread, has been added the Threads list, the system is not at a
488 // safepoint and the Thread is not "protected".
489 //
490 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
491 assert(!thread->is_Java_thread() || Thread::current() == thread ||
492 !((JavaThread *) thread)->on_thread_list() ||
493 SafepointSynchronize::is_at_safepoint() ||
494 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
495 "possibility of dangling Thread pointer");
496 }
497 #endif
498
499 ThreadPriority Thread::get_priority(const Thread* const thread) {
500 ThreadPriority priority;
501 // Can return an error!
502 (void)os::get_priority(thread, priority);
503 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
504 return priority;
505 }
506
507 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
508 debug_only(check_for_dangling_thread_pointer(thread);)
509 // Can return an error!
510 (void)os::set_priority(thread, priority);
511 }
512
513
514 void Thread::start(Thread* thread) {
515 // Start is different from resume in that its safety is guaranteed by context or
516 // being called from a Java method synchronized on the Thread object.
517 if (!DisableStartThread) {
518 if (thread->is_Java_thread()) {
519 // Initialize the thread state to RUNNABLE before starting this thread.
520 // Can not set it after the thread started because we do not know the
521 // exact thread state at that time. It could be in MONITOR_WAIT or
522 // in SLEEPING or some other state.
523 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
524 java_lang_Thread::RUNNABLE);
525 }
526 os::start_thread(thread);
527 }
528 }
529
530 // Enqueue a VM_Operation to do the job for us - sometime later
531 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
532 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
533 VMThread::execute(vm_stop);
534 }
535
536
537 // Check if an external suspend request has completed (or has been
538 // cancelled). Returns true if the thread is externally suspended and
539 // false otherwise.
540 //
541 // The bits parameter returns information about the code path through
542 // the routine. Useful for debugging:
543 //
544 // set in is_ext_suspend_completed():
545 // 0x00000001 - routine was entered
546 // 0x00000010 - routine return false at end
547 // 0x00000100 - thread exited (return false)
548 // 0x00000200 - suspend request cancelled (return false)
549 // 0x00000400 - thread suspended (return true)
550 // 0x00001000 - thread is in a suspend equivalent state (return true)
551 // 0x00002000 - thread is native and walkable (return true)
552 // 0x00004000 - thread is native_trans and walkable (needed retry)
553 //
554 // set in wait_for_ext_suspend_completion():
555 // 0x00010000 - routine was entered
556 // 0x00020000 - suspend request cancelled before loop (return false)
557 // 0x00040000 - thread suspended before loop (return true)
558 // 0x00080000 - suspend request cancelled in loop (return false)
559 // 0x00100000 - thread suspended in loop (return true)
560 // 0x00200000 - suspend not completed during retry loop (return false)
561
562 // Helper class for tracing suspend wait debug bits.
563 //
564 // 0x00000100 indicates that the target thread exited before it could
565 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
566 // 0x00080000 each indicate a cancelled suspend request so they don't
567 // count as wait failures either.
568 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
569
570 class TraceSuspendDebugBits : public StackObj {
571 private:
572 JavaThread * jt;
573 bool is_wait;
574 bool called_by_wait; // meaningful when !is_wait
575 uint32_t * bits;
576
577 public:
578 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
579 uint32_t *_bits) {
580 jt = _jt;
581 is_wait = _is_wait;
582 called_by_wait = _called_by_wait;
583 bits = _bits;
584 }
585
586 ~TraceSuspendDebugBits() {
587 if (!is_wait) {
588 #if 1
589 // By default, don't trace bits for is_ext_suspend_completed() calls.
590 // That trace is very chatty.
591 return;
592 #else
593 if (!called_by_wait) {
594 // If tracing for is_ext_suspend_completed() is enabled, then only
595 // trace calls to it from wait_for_ext_suspend_completion()
596 return;
597 }
598 #endif
599 }
600
601 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
602 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
603 MutexLocker ml(Threads_lock); // needed for get_thread_name()
604 ResourceMark rm;
605
606 tty->print_cr(
607 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
608 jt->get_thread_name(), *bits);
609
610 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
611 }
612 }
613 }
614 };
615 #undef DEBUG_FALSE_BITS
616
617
618 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
619 uint32_t *bits) {
620 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
621
622 bool did_trans_retry = false; // only do thread_in_native_trans retry once
623 bool do_trans_retry; // flag to force the retry
624
625 *bits |= 0x00000001;
626
627 do {
628 do_trans_retry = false;
629
630 if (is_exiting()) {
631 // Thread is in the process of exiting. This is always checked
632 // first to reduce the risk of dereferencing a freed JavaThread.
633 *bits |= 0x00000100;
634 return false;
635 }
636
637 if (!is_external_suspend()) {
638 // Suspend request is cancelled. This is always checked before
639 // is_ext_suspended() to reduce the risk of a rogue resume
640 // confusing the thread that made the suspend request.
641 *bits |= 0x00000200;
642 return false;
643 }
644
645 if (is_ext_suspended()) {
646 // thread is suspended
647 *bits |= 0x00000400;
648 return true;
649 }
650
651 // Now that we no longer do hard suspends of threads running
652 // native code, the target thread can be changing thread state
653 // while we are in this routine:
654 //
655 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
656 //
657 // We save a copy of the thread state as observed at this moment
658 // and make our decision about suspend completeness based on the
659 // copy. This closes the race where the thread state is seen as
660 // _thread_in_native_trans in the if-thread_blocked check, but is
661 // seen as _thread_blocked in if-thread_in_native_trans check.
662 JavaThreadState save_state = thread_state();
663
664 if (save_state == _thread_blocked && is_suspend_equivalent()) {
665 // If the thread's state is _thread_blocked and this blocking
666 // condition is known to be equivalent to a suspend, then we can
667 // consider the thread to be externally suspended. This means that
668 // the code that sets _thread_blocked has been modified to do
669 // self-suspension if the blocking condition releases. We also
670 // used to check for CONDVAR_WAIT here, but that is now covered by
671 // the _thread_blocked with self-suspension check.
672 //
673 // Return true since we wouldn't be here unless there was still an
674 // external suspend request.
675 *bits |= 0x00001000;
676 return true;
677 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
678 // Threads running native code will self-suspend on native==>VM/Java
679 // transitions. If its stack is walkable (should always be the case
680 // unless this function is called before the actual java_suspend()
681 // call), then the wait is done.
682 *bits |= 0x00002000;
683 return true;
684 } else if (!called_by_wait && !did_trans_retry &&
685 save_state == _thread_in_native_trans &&
686 frame_anchor()->walkable()) {
687 // The thread is transitioning from thread_in_native to another
688 // thread state. check_safepoint_and_suspend_for_native_trans()
689 // will force the thread to self-suspend. If it hasn't gotten
690 // there yet we may have caught the thread in-between the native
691 // code check above and the self-suspend. Lucky us. If we were
692 // called by wait_for_ext_suspend_completion(), then it
693 // will be doing the retries so we don't have to.
694 //
695 // Since we use the saved thread state in the if-statement above,
696 // there is a chance that the thread has already transitioned to
697 // _thread_blocked by the time we get here. In that case, we will
698 // make a single unnecessary pass through the logic below. This
699 // doesn't hurt anything since we still do the trans retry.
700
701 *bits |= 0x00004000;
702
703 // Once the thread leaves thread_in_native_trans for another
704 // thread state, we break out of this retry loop. We shouldn't
705 // need this flag to prevent us from getting back here, but
706 // sometimes paranoia is good.
707 did_trans_retry = true;
708
709 // We wait for the thread to transition to a more usable state.
710 for (int i = 1; i <= SuspendRetryCount; i++) {
711 // We used to do an "os::yield_all(i)" call here with the intention
712 // that yielding would increase on each retry. However, the parameter
713 // is ignored on Linux which means the yield didn't scale up. Waiting
714 // on the SR_lock below provides a much more predictable scale up for
715 // the delay. It also provides a simple/direct point to check for any
716 // safepoint requests from the VMThread
717
718 // temporarily drops SR_lock while doing wait with safepoint check
719 // (if we're a JavaThread - the WatcherThread can also call this)
720 // and increase delay with each retry
721 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
722
723 // check the actual thread state instead of what we saved above
724 if (thread_state() != _thread_in_native_trans) {
725 // the thread has transitioned to another thread state so
726 // try all the checks (except this one) one more time.
727 do_trans_retry = true;
728 break;
729 }
730 } // end retry loop
731
732
733 }
734 } while (do_trans_retry);
735
736 *bits |= 0x00000010;
737 return false;
738 }
739
740 // Wait for an external suspend request to complete (or be cancelled).
741 // Returns true if the thread is externally suspended and false otherwise.
742 //
743 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
744 uint32_t *bits) {
745 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
746 false /* !called_by_wait */, bits);
747
748 // local flag copies to minimize SR_lock hold time
749 bool is_suspended;
750 bool pending;
751 uint32_t reset_bits;
752
753 // set a marker so is_ext_suspend_completed() knows we are the caller
754 *bits |= 0x00010000;
755
756 // We use reset_bits to reinitialize the bits value at the top of
757 // each retry loop. This allows the caller to make use of any
758 // unused bits for their own marking purposes.
759 reset_bits = *bits;
760
761 {
762 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
763 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
764 delay, bits);
765 pending = is_external_suspend();
766 }
767 // must release SR_lock to allow suspension to complete
768
769 if (!pending) {
770 // A cancelled suspend request is the only false return from
771 // is_ext_suspend_completed() that keeps us from entering the
772 // retry loop.
773 *bits |= 0x00020000;
774 return false;
775 }
776
777 if (is_suspended) {
778 *bits |= 0x00040000;
779 return true;
780 }
781
782 for (int i = 1; i <= retries; i++) {
783 *bits = reset_bits; // reinit to only track last retry
784
785 // We used to do an "os::yield_all(i)" call here with the intention
786 // that yielding would increase on each retry. However, the parameter
787 // is ignored on Linux which means the yield didn't scale up. Waiting
788 // on the SR_lock below provides a much more predictable scale up for
789 // the delay. It also provides a simple/direct point to check for any
790 // safepoint requests from the VMThread
791
792 {
793 MutexLocker ml(SR_lock());
794 // wait with safepoint check (if we're a JavaThread - the WatcherThread
795 // can also call this) and increase delay with each retry
796 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
797
798 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
799 delay, bits);
800
801 // It is possible for the external suspend request to be cancelled
802 // (by a resume) before the actual suspend operation is completed.
803 // Refresh our local copy to see if we still need to wait.
804 pending = is_external_suspend();
805 }
806
807 if (!pending) {
808 // A cancelled suspend request is the only false return from
809 // is_ext_suspend_completed() that keeps us from staying in the
810 // retry loop.
811 *bits |= 0x00080000;
812 return false;
813 }
814
815 if (is_suspended) {
816 *bits |= 0x00100000;
817 return true;
818 }
819 } // end retry loop
820
821 // thread did not suspend after all our retries
822 *bits |= 0x00200000;
823 return false;
824 }
825
826 // Called from API entry points which perform stack walking. If the
827 // associated JavaThread is the current thread, then wait_for_suspend
828 // is not used. Otherwise, it determines if we should wait for the
829 // "other" thread to complete external suspension. (NOTE: in future
830 // releases the suspension mechanism should be reimplemented so this
831 // is not necessary.)
832 //
833 bool
834 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
835 if (this != JavaThread::current()) {
836 // "other" threads require special handling.
837 if (wait_for_suspend) {
838 // We are allowed to wait for the external suspend to complete
839 // so give the other thread a chance to get suspended.
840 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
841 SuspendRetryDelay, bits)) {
842 // Didn't make it so let the caller know.
843 return false;
844 }
845 }
846 // We aren't allowed to wait for the external suspend to complete
847 // so if the other thread isn't externally suspended we need to
848 // let the caller know.
849 else if (!is_ext_suspend_completed_with_lock(bits)) {
850 return false;
851 }
852 }
853
854 return true;
855 }
856
857 #ifndef PRODUCT
858 void JavaThread::record_jump(address target, address instr, const char* file,
859 int line) {
860
861 // This should not need to be atomic as the only way for simultaneous
862 // updates is via interrupts. Even then this should be rare or non-existent
863 // and we don't care that much anyway.
864
865 int index = _jmp_ring_index;
866 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
867 _jmp_ring[index]._target = (intptr_t) target;
868 _jmp_ring[index]._instruction = (intptr_t) instr;
869 _jmp_ring[index]._file = file;
870 _jmp_ring[index]._line = line;
871 }
872 #endif // PRODUCT
873
874 void Thread::interrupt(Thread* thread) {
875 debug_only(check_for_dangling_thread_pointer(thread);)
876 os::interrupt(thread);
877 }
878
879 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
880 debug_only(check_for_dangling_thread_pointer(thread);)
881 // Note: If clear_interrupted==false, this simply fetches and
882 // returns the value of the field osthread()->interrupted().
883 return os::is_interrupted(thread, clear_interrupted);
884 }
885
886
887 // GC Support
888 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
889 int thread_parity = _oops_do_parity;
890 if (thread_parity != strong_roots_parity) {
891 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
892 if (res == thread_parity) {
893 return true;
894 } else {
895 guarantee(res == strong_roots_parity, "Or else what?");
896 return false;
897 }
898 }
899 return false;
900 }
901
902 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
903 active_handles()->oops_do(f);
904 // Do oop for ThreadShadow
905 f->do_oop((oop*)&_pending_exception);
906 handle_area()->oops_do(f);
907
908 // We scan thread local monitor lists here, and the remaining global
909 // monitors in ObjectSynchronizer::oops_do().
910 ObjectSynchronizer::thread_local_used_oops_do(this, f);
911 }
912
913 void Thread::metadata_handles_do(void f(Metadata*)) {
914 // Only walk the Handles in Thread.
915 if (metadata_handles() != NULL) {
916 for (int i = 0; i< metadata_handles()->length(); i++) {
917 f(metadata_handles()->at(i));
918 }
919 }
920 }
921
922 void Thread::print_on(outputStream* st, bool print_extended_info) const {
923 // get_priority assumes osthread initialized
924 if (osthread() != NULL) {
925 int os_prio;
926 if (os::get_native_priority(this, &os_prio) == OS_OK) {
927 st->print("os_prio=%d ", os_prio);
928 }
929
930 st->print("cpu=%.2fms ",
931 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
932 );
933 st->print("elapsed=%.2fs ",
934 _statistical_info.getElapsedTime() / 1000.0
935 );
936 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
937 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
938 st->print("allocated=" SIZE_FORMAT "%s ",
939 byte_size_in_proper_unit(allocated_bytes),
940 proper_unit_for_byte_size(allocated_bytes)
941 );
942 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
943 }
944
945 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
946 osthread()->print_on(st);
947 }
948 ThreadsSMRSupport::print_info_on(this, st);
949 st->print(" ");
950 debug_only(if (WizardMode) print_owned_locks_on(st);)
951 }
952
953 // Thread::print_on_error() is called by fatal error handler. Don't use
954 // any lock or allocate memory.
955 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
956 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
957
958 if (is_VM_thread()) { st->print("VMThread"); }
959 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
960 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
961 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
962 else { st->print("Thread"); }
963
964 if (is_Named_thread()) {
965 st->print(" \"%s\"", name());
966 }
967
968 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
969 p2i(stack_end()), p2i(stack_base()));
970
971 if (osthread()) {
972 st->print(" [id=%d]", osthread()->thread_id());
973 }
974
975 ThreadsSMRSupport::print_info_on(this, st);
976 }
977
978 void Thread::print_value_on(outputStream* st) const {
979 if (is_Named_thread()) {
980 st->print(" \"%s\" ", name());
981 }
982 st->print(INTPTR_FORMAT, p2i(this)); // print address
983 }
984
985 #ifdef ASSERT
986 void Thread::print_owned_locks_on(outputStream* st) const {
987 Monitor *cur = _owned_locks;
988 if (cur == NULL) {
989 st->print(" (no locks) ");
990 } else {
991 st->print_cr(" Locks owned:");
992 while (cur) {
993 cur->print_on(st);
994 cur = cur->next();
995 }
996 }
997 }
998
999 static int ref_use_count = 0;
1000
1001 bool Thread::owns_locks_but_compiled_lock() const {
1002 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1003 if (cur != Compile_lock) return true;
1004 }
1005 return false;
1006 }
1007
1008
1009 #endif
1010
1011 #ifndef PRODUCT
1012
1013 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
1014 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
1015 // no locks which allow_vm_block's are held
1016 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
1017 // Check if current thread is allowed to block at a safepoint
1018 if (!(_allow_safepoint_count == 0)) {
1019 fatal("Possible safepoint reached by thread that does not allow it");
1020 }
1021 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
1022 fatal("LEAF method calling lock?");
1023 }
1024
1025 #ifdef ASSERT
1026 if (potential_vm_operation && is_Java_thread()
1027 && !Universe::is_bootstrapping()) {
1028 // Make sure we do not hold any locks that the VM thread also uses.
1029 // This could potentially lead to deadlocks
1030 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1031 // Threads_lock is special, since the safepoint synchronization will not start before this is
1032 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
1033 // since it is used to transfer control between JavaThreads and the VMThread
1034 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
1035 if ((cur->allow_vm_block() &&
1036 cur != Threads_lock &&
1037 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
1038 cur != VMOperationRequest_lock &&
1039 cur != VMOperationQueue_lock) ||
1040 cur->rank() == Mutex::special) {
1041 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
1042 }
1043 }
1044 }
1045
1046 if (GCALotAtAllSafepoints) {
1047 // We could enter a safepoint here and thus have a gc
1048 InterfaceSupport::check_gc_alot();
1049 }
1050 #endif
1051 }
1052 #endif
1053
1054 bool Thread::is_in_stack(address adr) const {
1055 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1056 address end = os::current_stack_pointer();
1057 // Allow non Java threads to call this without stack_base
1058 if (_stack_base == NULL) return true;
1059 if (stack_base() >= adr && adr >= end) return true;
1060
1061 return false;
1062 }
1063
1064 bool Thread::is_in_usable_stack(address adr) const {
1065 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1066 size_t usable_stack_size = _stack_size - stack_guard_size;
1067
1068 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1069 }
1070
1071
1072 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1073 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1074 // used for compilation in the future. If that change is made, the need for these methods
1075 // should be revisited, and they should be removed if possible.
1076
1077 bool Thread::is_lock_owned(address adr) const {
1078 return on_local_stack(adr);
1079 }
1080
1081 bool Thread::set_as_starting_thread() {
1082 assert(_starting_thread == NULL, "already initialized: "
1083 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
1084 // NOTE: this must be called inside the main thread.
1085 DEBUG_ONLY(_starting_thread = this;)
1086 return os::create_main_thread((JavaThread*)this);
1087 }
1088
1089 static void initialize_class(Symbol* class_name, TRAPS) {
1090 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1091 InstanceKlass::cast(klass)->initialize(CHECK);
1092 }
1093
1094
1095 // Creates the initial ThreadGroup
1096 static Handle create_initial_thread_group(TRAPS) {
1097 Handle system_instance = JavaCalls::construct_new_instance(
1098 SystemDictionary::ThreadGroup_klass(),
1099 vmSymbols::void_method_signature(),
1100 CHECK_NH);
1101 Universe::set_system_thread_group(system_instance());
1102
1103 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1104 Handle main_instance = JavaCalls::construct_new_instance(
1105 SystemDictionary::ThreadGroup_klass(),
1106 vmSymbols::threadgroup_string_void_signature(),
1107 system_instance,
1108 string,
1109 CHECK_NH);
1110 return main_instance;
1111 }
1112
1113 // Creates the initial Thread
1114 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1115 TRAPS) {
1116 InstanceKlass* ik = SystemDictionary::Thread_klass();
1117 assert(ik->is_initialized(), "must be");
1118 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1119
1120 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1121 // constructor calls Thread.current(), which must be set here for the
1122 // initial thread.
1123 java_lang_Thread::set_thread(thread_oop(), thread);
1124 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1125 thread->set_threadObj(thread_oop());
1126
1127 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1128
1129 JavaValue result(T_VOID);
1130 JavaCalls::call_special(&result, thread_oop,
1131 ik,
1132 vmSymbols::object_initializer_name(),
1133 vmSymbols::threadgroup_string_void_signature(),
1134 thread_group,
1135 string,
1136 CHECK_NULL);
1137 return thread_oop();
1138 }
1139
1140 char java_runtime_name[128] = "";
1141 char java_runtime_version[128] = "";
1142
1143 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1144 static const char* get_java_runtime_name(TRAPS) {
1145 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1146 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1147 fieldDescriptor fd;
1148 bool found = k != NULL &&
1149 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1150 vmSymbols::string_signature(), &fd);
1151 if (found) {
1152 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1153 if (name_oop == NULL) {
1154 return NULL;
1155 }
1156 const char* name = java_lang_String::as_utf8_string(name_oop,
1157 java_runtime_name,
1158 sizeof(java_runtime_name));
1159 return name;
1160 } else {
1161 return NULL;
1162 }
1163 }
1164
1165 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1166 static const char* get_java_runtime_version(TRAPS) {
1167 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1168 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1169 fieldDescriptor fd;
1170 bool found = k != NULL &&
1171 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1172 vmSymbols::string_signature(), &fd);
1173 if (found) {
1174 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1175 if (name_oop == NULL) {
1176 return NULL;
1177 }
1178 const char* name = java_lang_String::as_utf8_string(name_oop,
1179 java_runtime_version,
1180 sizeof(java_runtime_version));
1181 return name;
1182 } else {
1183 return NULL;
1184 }
1185 }
1186
1187 // General purpose hook into Java code, run once when the VM is initialized.
1188 // The Java library method itself may be changed independently from the VM.
1189 static void call_postVMInitHook(TRAPS) {
1190 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1191 if (klass != NULL) {
1192 JavaValue result(T_VOID);
1193 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1194 vmSymbols::void_method_signature(),
1195 CHECK);
1196 }
1197 }
1198
1199 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1200 bool daemon, TRAPS) {
1201 assert(thread_group.not_null(), "thread group should be specified");
1202 assert(threadObj() == NULL, "should only create Java thread object once");
1203
1204 InstanceKlass* ik = SystemDictionary::Thread_klass();
1205 assert(ik->is_initialized(), "must be");
1206 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1207
1208 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1209 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1210 // constructor calls Thread.current(), which must be set here.
1211 java_lang_Thread::set_thread(thread_oop(), this);
1212 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1213 set_threadObj(thread_oop());
1214
1215 JavaValue result(T_VOID);
1216 if (thread_name != NULL) {
1217 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1218 // Thread gets assigned specified name and null target
1219 JavaCalls::call_special(&result,
1220 thread_oop,
1221 ik,
1222 vmSymbols::object_initializer_name(),
1223 vmSymbols::threadgroup_string_void_signature(),
1224 thread_group,
1225 name,
1226 THREAD);
1227 } else {
1228 // Thread gets assigned name "Thread-nnn" and null target
1229 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1230 JavaCalls::call_special(&result,
1231 thread_oop,
1232 ik,
1233 vmSymbols::object_initializer_name(),
1234 vmSymbols::threadgroup_runnable_void_signature(),
1235 thread_group,
1236 Handle(),
1237 THREAD);
1238 }
1239
1240
1241 if (daemon) {
1242 java_lang_Thread::set_daemon(thread_oop());
1243 }
1244
1245 if (HAS_PENDING_EXCEPTION) {
1246 return;
1247 }
1248
1249 Klass* group = SystemDictionary::ThreadGroup_klass();
1250 Handle threadObj(THREAD, this->threadObj());
1251
1252 JavaCalls::call_special(&result,
1253 thread_group,
1254 group,
1255 vmSymbols::add_method_name(),
1256 vmSymbols::thread_void_signature(),
1257 threadObj, // Arg 1
1258 THREAD);
1259 }
1260
1261 // List of all NonJavaThreads and safe iteration over that list.
1262
1263 class NonJavaThread::List {
1264 public:
1265 NonJavaThread* volatile _head;
1266 SingleWriterSynchronizer _protect;
1267
1268 List() : _head(NULL), _protect() {}
1269 };
1270
1271 NonJavaThread::List NonJavaThread::_the_list;
1272
1273 NonJavaThread::Iterator::Iterator() :
1274 _protect_enter(_the_list._protect.enter()),
1275 _current(OrderAccess::load_acquire(&_the_list._head))
1276 {}
1277
1278 NonJavaThread::Iterator::~Iterator() {
1279 _the_list._protect.exit(_protect_enter);
1280 }
1281
1282 void NonJavaThread::Iterator::step() {
1283 assert(!end(), "precondition");
1284 _current = OrderAccess::load_acquire(&_current->_next);
1285 }
1286
1287 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) {
1288 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!");
1289 }
1290
1291 NonJavaThread::~NonJavaThread() { }
1292
1293 void NonJavaThread::add_to_the_list() {
1294 MutexLockerEx lock(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1295 _next = _the_list._head;
1296 OrderAccess::release_store(&_the_list._head, this);
1297 }
1298
1299 void NonJavaThread::remove_from_the_list() {
1300 MutexLockerEx lock(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1301 NonJavaThread* volatile* p = &_the_list._head;
1302 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) {
1303 if (t == this) {
1304 *p = this->_next;
1305 // Wait for any in-progress iterators. Concurrent synchronize is
1306 // not allowed, so do it while holding the list lock.
1307 _the_list._protect.synchronize();
1308 break;
1309 }
1310 }
1311 }
1312
1313 void NonJavaThread::pre_run() {
1314 assert(BarrierSet::barrier_set() != NULL, "invariant");
1315 add_to_the_list();
1316
1317 // This is slightly odd in that NamedThread is a subclass, but
1318 // in fact name() is defined in Thread
1319 assert(this->name() != NULL, "thread name was not set before it was started");
1320 this->set_native_thread_name(this->name());
1321 }
1322
1323 void NonJavaThread::post_run() {
1324 JFR_ONLY(Jfr::on_thread_exit(this);)
1325 remove_from_the_list();
1326 // Ensure thread-local-storage is cleared before termination.
1327 Thread::clear_thread_current();
1328 }
1329
1330 // NamedThread -- non-JavaThread subclasses with multiple
1331 // uniquely named instances should derive from this.
1332 NamedThread::NamedThread() :
1333 NonJavaThread(),
1334 _name(NULL),
1335 _processed_thread(NULL),
1336 _gc_id(GCId::undefined())
1337 {}
1338
1339 NamedThread::~NamedThread() {
1340 if (_name != NULL) {
1341 FREE_C_HEAP_ARRAY(char, _name);
1342 _name = NULL;
1343 }
1344 }
1345
1346 void NamedThread::set_name(const char* format, ...) {
1347 guarantee(_name == NULL, "Only get to set name once.");
1348 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1349 guarantee(_name != NULL, "alloc failure");
1350 va_list ap;
1351 va_start(ap, format);
1352 jio_vsnprintf(_name, max_name_len, format, ap);
1353 va_end(ap);
1354 }
1355
1356 void NamedThread::print_on(outputStream* st) const {
1357 st->print("\"%s\" ", name());
1358 Thread::print_on(st);
1359 st->cr();
1360 }
1361
1362
1363 // ======= WatcherThread ========
1364
1365 // The watcher thread exists to simulate timer interrupts. It should
1366 // be replaced by an abstraction over whatever native support for
1367 // timer interrupts exists on the platform.
1368
1369 WatcherThread* WatcherThread::_watcher_thread = NULL;
1370 bool WatcherThread::_startable = false;
1371 volatile bool WatcherThread::_should_terminate = false;
1372
1373 WatcherThread::WatcherThread() : NonJavaThread() {
1374 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1375 if (os::create_thread(this, os::watcher_thread)) {
1376 _watcher_thread = this;
1377
1378 // Set the watcher thread to the highest OS priority which should not be
1379 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1380 // is created. The only normal thread using this priority is the reference
1381 // handler thread, which runs for very short intervals only.
1382 // If the VMThread's priority is not lower than the WatcherThread profiling
1383 // will be inaccurate.
1384 os::set_priority(this, MaxPriority);
1385 if (!DisableStartThread) {
1386 os::start_thread(this);
1387 }
1388 }
1389 }
1390
1391 int WatcherThread::sleep() const {
1392 // The WatcherThread does not participate in the safepoint protocol
1393 // for the PeriodicTask_lock because it is not a JavaThread.
1394 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1395
1396 if (_should_terminate) {
1397 // check for termination before we do any housekeeping or wait
1398 return 0; // we did not sleep.
1399 }
1400
1401 // remaining will be zero if there are no tasks,
1402 // causing the WatcherThread to sleep until a task is
1403 // enrolled
1404 int remaining = PeriodicTask::time_to_wait();
1405 int time_slept = 0;
1406
1407 // we expect this to timeout - we only ever get unparked when
1408 // we should terminate or when a new task has been enrolled
1409 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1410
1411 jlong time_before_loop = os::javaTimeNanos();
1412
1413 while (true) {
1414 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1415 remaining);
1416 jlong now = os::javaTimeNanos();
1417
1418 if (remaining == 0) {
1419 // if we didn't have any tasks we could have waited for a long time
1420 // consider the time_slept zero and reset time_before_loop
1421 time_slept = 0;
1422 time_before_loop = now;
1423 } else {
1424 // need to recalculate since we might have new tasks in _tasks
1425 time_slept = (int) ((now - time_before_loop) / 1000000);
1426 }
1427
1428 // Change to task list or spurious wakeup of some kind
1429 if (timedout || _should_terminate) {
1430 break;
1431 }
1432
1433 remaining = PeriodicTask::time_to_wait();
1434 if (remaining == 0) {
1435 // Last task was just disenrolled so loop around and wait until
1436 // another task gets enrolled
1437 continue;
1438 }
1439
1440 remaining -= time_slept;
1441 if (remaining <= 0) {
1442 break;
1443 }
1444 }
1445
1446 return time_slept;
1447 }
1448
1449 void WatcherThread::run() {
1450 assert(this == watcher_thread(), "just checking");
1451
1452 this->set_active_handles(JNIHandleBlock::allocate_block());
1453 while (true) {
1454 assert(watcher_thread() == Thread::current(), "thread consistency check");
1455 assert(watcher_thread() == this, "thread consistency check");
1456
1457 // Calculate how long it'll be until the next PeriodicTask work
1458 // should be done, and sleep that amount of time.
1459 int time_waited = sleep();
1460
1461 if (VMError::is_error_reported()) {
1462 // A fatal error has happened, the error handler(VMError::report_and_die)
1463 // should abort JVM after creating an error log file. However in some
1464 // rare cases, the error handler itself might deadlock. Here periodically
1465 // check for error reporting timeouts, and if it happens, just proceed to
1466 // abort the VM.
1467
1468 // This code is in WatcherThread because WatcherThread wakes up
1469 // periodically so the fatal error handler doesn't need to do anything;
1470 // also because the WatcherThread is less likely to crash than other
1471 // threads.
1472
1473 for (;;) {
1474 // Note: we use naked sleep in this loop because we want to avoid using
1475 // any kind of VM infrastructure which may be broken at this point.
1476 if (VMError::check_timeout()) {
1477 // We hit error reporting timeout. Error reporting was interrupted and
1478 // will be wrapping things up now (closing files etc). Give it some more
1479 // time, then quit the VM.
1480 os::naked_short_sleep(200);
1481 // Print a message to stderr.
1482 fdStream err(defaultStream::output_fd());
1483 err.print_raw_cr("# [ timer expired, abort... ]");
1484 // skip atexit/vm_exit/vm_abort hooks
1485 os::die();
1486 }
1487
1488 // Wait a second, then recheck for timeout.
1489 os::naked_short_sleep(999);
1490 }
1491 }
1492
1493 if (_should_terminate) {
1494 // check for termination before posting the next tick
1495 break;
1496 }
1497
1498 PeriodicTask::real_time_tick(time_waited);
1499 }
1500
1501 // Signal that it is terminated
1502 {
1503 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1504 _watcher_thread = NULL;
1505 Terminator_lock->notify();
1506 }
1507 }
1508
1509 void WatcherThread::start() {
1510 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1511
1512 if (watcher_thread() == NULL && _startable) {
1513 _should_terminate = false;
1514 // Create the single instance of WatcherThread
1515 new WatcherThread();
1516 }
1517 }
1518
1519 void WatcherThread::make_startable() {
1520 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1521 _startable = true;
1522 }
1523
1524 void WatcherThread::stop() {
1525 {
1526 // Follow normal safepoint aware lock enter protocol since the
1527 // WatcherThread is stopped by another JavaThread.
1528 MutexLocker ml(PeriodicTask_lock);
1529 _should_terminate = true;
1530
1531 WatcherThread* watcher = watcher_thread();
1532 if (watcher != NULL) {
1533 // unpark the WatcherThread so it can see that it should terminate
1534 watcher->unpark();
1535 }
1536 }
1537
1538 MutexLocker mu(Terminator_lock);
1539
1540 while (watcher_thread() != NULL) {
1541 // This wait should make safepoint checks, wait without a timeout,
1542 // and wait as a suspend-equivalent condition.
1543 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1544 Mutex::_as_suspend_equivalent_flag);
1545 }
1546 }
1547
1548 void WatcherThread::unpark() {
1549 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1550 PeriodicTask_lock->notify();
1551 }
1552
1553 void WatcherThread::print_on(outputStream* st) const {
1554 st->print("\"%s\" ", name());
1555 Thread::print_on(st);
1556 st->cr();
1557 }
1558
1559 // ======= JavaThread ========
1560
1561 #if INCLUDE_JVMCI
1562
1563 jlong* JavaThread::_jvmci_old_thread_counters;
1564
1565 bool jvmci_counters_include(JavaThread* thread) {
1566 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1567 }
1568
1569 void JavaThread::collect_counters(typeArrayOop array) {
1570 if (JVMCICounterSize > 0) {
1571 JavaThreadIteratorWithHandle jtiwh;
1572 for (int i = 0; i < array->length(); i++) {
1573 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1574 }
1575 for (; JavaThread *tp = jtiwh.next(); ) {
1576 if (jvmci_counters_include(tp)) {
1577 for (int i = 0; i < array->length(); i++) {
1578 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1579 }
1580 }
1581 }
1582 }
1583 }
1584
1585 #endif // INCLUDE_JVMCI
1586
1587 // A JavaThread is a normal Java thread
1588
1589 void JavaThread::initialize() {
1590 // Initialize fields
1591
1592 set_saved_exception_pc(NULL);
1593 set_threadObj(NULL);
1594 _anchor.clear();
1595 set_entry_point(NULL);
1596 set_jni_functions(jni_functions());
1597 set_callee_target(NULL);
1598 set_vm_result(NULL);
1599 set_vm_result_2(NULL);
1600 set_vframe_array_head(NULL);
1601 set_vframe_array_last(NULL);
1602 set_deferred_locals(NULL);
1603 set_deopt_mark(NULL);
1604 set_deopt_compiled_method(NULL);
1605 clear_must_deopt_id();
1606 set_monitor_chunks(NULL);
1607 set_next(NULL);
1608 _on_thread_list = false;
1609 set_thread_state(_thread_new);
1610 _terminated = _not_terminated;
1611 _array_for_gc = NULL;
1612 _suspend_equivalent = false;
1613 _in_deopt_handler = 0;
1614 _doing_unsafe_access = false;
1615 _stack_guard_state = stack_guard_unused;
1616 #if INCLUDE_JVMCI
1617 _pending_monitorenter = false;
1618 _pending_deoptimization = -1;
1619 _pending_failed_speculation = 0;
1620 _pending_transfer_to_interpreter = false;
1621 _adjusting_comp_level = false;
1622 _in_retryable_allocation = false;
1623 _jvmci._alternate_call_target = NULL;
1624 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1625 if (JVMCICounterSize > 0) {
1626 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1627 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1628 } else {
1629 _jvmci_counters = NULL;
1630 }
1631 #endif // INCLUDE_JVMCI
1632 _reserved_stack_activation = NULL; // stack base not known yet
1633 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1634 _exception_pc = 0;
1635 _exception_handler_pc = 0;
1636 _is_method_handle_return = 0;
1637 _jvmti_thread_state= NULL;
1638 _should_post_on_exceptions_flag = JNI_FALSE;
1639 _interp_only_mode = 0;
1640 _special_runtime_exit_condition = _no_async_condition;
1641 _pending_async_exception = NULL;
1642 _thread_stat = NULL;
1643 _thread_stat = new ThreadStatistics();
1644 _blocked_on_compilation = false;
1645 _jni_active_critical = 0;
1646 _pending_jni_exception_check_fn = NULL;
1647 _do_not_unlock_if_synchronized = false;
1648 _cached_monitor_info = NULL;
1649 _parker = Parker::Allocate(this);
1650
1651 #ifndef PRODUCT
1652 _jmp_ring_index = 0;
1653 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1654 record_jump(NULL, NULL, NULL, 0);
1655 }
1656 #endif // PRODUCT
1657
1658 // Setup safepoint state info for this thread
1659 ThreadSafepointState::create(this);
1660
1661 debug_only(_java_call_counter = 0);
1662
1663 // JVMTI PopFrame support
1664 _popframe_condition = popframe_inactive;
1665 _popframe_preserved_args = NULL;
1666 _popframe_preserved_args_size = 0;
1667 _frames_to_pop_failed_realloc = 0;
1668
1669 if (SafepointMechanism::uses_thread_local_poll()) {
1670 SafepointMechanism::initialize_header(this);
1671 }
1672
1673 _class_to_be_initialized = NULL;
1674
1675 pd_initialize();
1676 }
1677
1678 JavaThread::JavaThread(bool is_attaching_via_jni) :
1679 Thread() {
1680 initialize();
1681 if (is_attaching_via_jni) {
1682 _jni_attach_state = _attaching_via_jni;
1683 } else {
1684 _jni_attach_state = _not_attaching_via_jni;
1685 }
1686 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1687 }
1688
1689 bool JavaThread::reguard_stack(address cur_sp) {
1690 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1691 && _stack_guard_state != stack_guard_reserved_disabled) {
1692 return true; // Stack already guarded or guard pages not needed.
1693 }
1694
1695 if (register_stack_overflow()) {
1696 // For those architectures which have separate register and
1697 // memory stacks, we must check the register stack to see if
1698 // it has overflowed.
1699 return false;
1700 }
1701
1702 // Java code never executes within the yellow zone: the latter is only
1703 // there to provoke an exception during stack banging. If java code
1704 // is executing there, either StackShadowPages should be larger, or
1705 // some exception code in c1, c2 or the interpreter isn't unwinding
1706 // when it should.
1707 guarantee(cur_sp > stack_reserved_zone_base(),
1708 "not enough space to reguard - increase StackShadowPages");
1709 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1710 enable_stack_yellow_reserved_zone();
1711 if (reserved_stack_activation() != stack_base()) {
1712 set_reserved_stack_activation(stack_base());
1713 }
1714 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1715 set_reserved_stack_activation(stack_base());
1716 enable_stack_reserved_zone();
1717 }
1718 return true;
1719 }
1720
1721 bool JavaThread::reguard_stack(void) {
1722 return reguard_stack(os::current_stack_pointer());
1723 }
1724
1725
1726 void JavaThread::block_if_vm_exited() {
1727 if (_terminated == _vm_exited) {
1728 // _vm_exited is set at safepoint, and Threads_lock is never released
1729 // we will block here forever
1730 Threads_lock->lock_without_safepoint_check();
1731 ShouldNotReachHere();
1732 }
1733 }
1734
1735
1736 // Remove this ifdef when C1 is ported to the compiler interface.
1737 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1738 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1739
1740 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1741 Thread() {
1742 initialize();
1743 _jni_attach_state = _not_attaching_via_jni;
1744 set_entry_point(entry_point);
1745 // Create the native thread itself.
1746 // %note runtime_23
1747 os::ThreadType thr_type = os::java_thread;
1748 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1749 os::java_thread;
1750 os::create_thread(this, thr_type, stack_sz);
1751 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1752 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1753 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1754 // the exception consists of creating the exception object & initializing it, initialization
1755 // will leave the VM via a JavaCall and then all locks must be unlocked).
1756 //
1757 // The thread is still suspended when we reach here. Thread must be explicit started
1758 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1759 // by calling Threads:add. The reason why this is not done here, is because the thread
1760 // object must be fully initialized (take a look at JVM_Start)
1761 }
1762
1763 JavaThread::~JavaThread() {
1764
1765 // JSR166 -- return the parker to the free list
1766 Parker::Release(_parker);
1767 _parker = NULL;
1768
1769 // Free any remaining previous UnrollBlock
1770 vframeArray* old_array = vframe_array_last();
1771
1772 if (old_array != NULL) {
1773 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1774 old_array->set_unroll_block(NULL);
1775 delete old_info;
1776 delete old_array;
1777 }
1778
1779 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1780 if (deferred != NULL) {
1781 // This can only happen if thread is destroyed before deoptimization occurs.
1782 assert(deferred->length() != 0, "empty array!");
1783 do {
1784 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1785 deferred->remove_at(0);
1786 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1787 delete dlv;
1788 } while (deferred->length() != 0);
1789 delete deferred;
1790 }
1791
1792 // All Java related clean up happens in exit
1793 ThreadSafepointState::destroy(this);
1794 if (_thread_stat != NULL) delete _thread_stat;
1795
1796 #if INCLUDE_JVMCI
1797 if (JVMCICounterSize > 0) {
1798 if (jvmci_counters_include(this)) {
1799 for (int i = 0; i < JVMCICounterSize; i++) {
1800 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1801 }
1802 }
1803 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1804 }
1805 #endif // INCLUDE_JVMCI
1806 }
1807
1808
1809 // First JavaThread specific code executed by a new Java thread.
1810 void JavaThread::pre_run() {
1811 // empty - see comments in run()
1812 }
1813
1814 // The main routine called by a new Java thread. This isn't overridden
1815 // by subclasses, instead different subclasses define a different "entry_point"
1816 // which defines the actual logic for that kind of thread.
1817 void JavaThread::run() {
1818 // initialize thread-local alloc buffer related fields
1819 this->initialize_tlab();
1820
1821 // Used to test validity of stack trace backs.
1822 // This can't be moved into pre_run() else we invalidate
1823 // the requirement that thread_main_inner is lower on
1824 // the stack. Consequently all the initialization logic
1825 // stays here in run() rather than pre_run().
1826 this->record_base_of_stack_pointer();
1827
1828 this->create_stack_guard_pages();
1829
1830 this->cache_global_variables();
1831
1832 // Thread is now sufficiently initialized to be handled by the safepoint code as being
1833 // in the VM. Change thread state from _thread_new to _thread_in_vm
1834 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1835
1836 assert(JavaThread::current() == this, "sanity check");
1837 assert(!Thread::current()->owns_locks(), "sanity check");
1838
1839 DTRACE_THREAD_PROBE(start, this);
1840
1841 // This operation might block. We call that after all safepoint checks for a new thread has
1842 // been completed.
1843 this->set_active_handles(JNIHandleBlock::allocate_block());
1844
1845 if (JvmtiExport::should_post_thread_life()) {
1846 JvmtiExport::post_thread_start(this);
1847
1848 }
1849
1850 // We call another function to do the rest so we are sure that the stack addresses used
1851 // from there will be lower than the stack base just computed.
1852 thread_main_inner();
1853 }
1854
1855 void JavaThread::thread_main_inner() {
1856 assert(JavaThread::current() == this, "sanity check");
1857 assert(this->threadObj() != NULL, "just checking");
1858
1859 // Execute thread entry point unless this thread has a pending exception
1860 // or has been stopped before starting.
1861 // Note: Due to JVM_StopThread we can have pending exceptions already!
1862 if (!this->has_pending_exception() &&
1863 !java_lang_Thread::is_stillborn(this->threadObj())) {
1864 {
1865 ResourceMark rm(this);
1866 this->set_native_thread_name(this->get_thread_name());
1867 }
1868 HandleMark hm(this);
1869 this->entry_point()(this, this);
1870 }
1871
1872 DTRACE_THREAD_PROBE(stop, this);
1873
1874 // Cleanup is handled in post_run()
1875 }
1876
1877 // Shared teardown for all JavaThreads
1878 void JavaThread::post_run() {
1879 this->exit(false);
1880 // Defer deletion to here to ensure 'this' is still referenceable in call_run
1881 // for any shared tear-down.
1882 this->smr_delete();
1883 }
1884
1885 static void ensure_join(JavaThread* thread) {
1886 // We do not need to grab the Threads_lock, since we are operating on ourself.
1887 Handle threadObj(thread, thread->threadObj());
1888 assert(threadObj.not_null(), "java thread object must exist");
1889 ObjectLocker lock(threadObj, thread);
1890 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1891 thread->clear_pending_exception();
1892 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1893 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1894 // Clear the native thread instance - this makes isAlive return false and allows the join()
1895 // to complete once we've done the notify_all below
1896 java_lang_Thread::set_thread(threadObj(), NULL);
1897 lock.notify_all(thread);
1898 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1899 thread->clear_pending_exception();
1900 }
1901
1902 static bool is_daemon(oop threadObj) {
1903 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
1904 }
1905
1906 // For any new cleanup additions, please check to see if they need to be applied to
1907 // cleanup_failed_attach_current_thread as well.
1908 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1909 assert(this == JavaThread::current(), "thread consistency check");
1910
1911 elapsedTimer _timer_exit_phase1;
1912 elapsedTimer _timer_exit_phase2;
1913 elapsedTimer _timer_exit_phase3;
1914 elapsedTimer _timer_exit_phase4;
1915
1916 if (log_is_enabled(Debug, os, thread, timer)) {
1917 _timer_exit_phase1.start();
1918 }
1919
1920 HandleMark hm(this);
1921 Handle uncaught_exception(this, this->pending_exception());
1922 this->clear_pending_exception();
1923 Handle threadObj(this, this->threadObj());
1924 assert(threadObj.not_null(), "Java thread object should be created");
1925
1926 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1927 {
1928 EXCEPTION_MARK;
1929
1930 CLEAR_PENDING_EXCEPTION;
1931 }
1932 if (!destroy_vm) {
1933 if (uncaught_exception.not_null()) {
1934 EXCEPTION_MARK;
1935 // Call method Thread.dispatchUncaughtException().
1936 Klass* thread_klass = SystemDictionary::Thread_klass();
1937 JavaValue result(T_VOID);
1938 JavaCalls::call_virtual(&result,
1939 threadObj, thread_klass,
1940 vmSymbols::dispatchUncaughtException_name(),
1941 vmSymbols::throwable_void_signature(),
1942 uncaught_exception,
1943 THREAD);
1944 if (HAS_PENDING_EXCEPTION) {
1945 ResourceMark rm(this);
1946 jio_fprintf(defaultStream::error_stream(),
1947 "\nException: %s thrown from the UncaughtExceptionHandler"
1948 " in thread \"%s\"\n",
1949 pending_exception()->klass()->external_name(),
1950 get_thread_name());
1951 CLEAR_PENDING_EXCEPTION;
1952 }
1953 }
1954 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
1955
1956 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1957 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1958 // is deprecated anyhow.
1959 if (!is_Compiler_thread()) {
1960 int count = 3;
1961 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1962 EXCEPTION_MARK;
1963 JavaValue result(T_VOID);
1964 Klass* thread_klass = SystemDictionary::Thread_klass();
1965 JavaCalls::call_virtual(&result,
1966 threadObj, thread_klass,
1967 vmSymbols::exit_method_name(),
1968 vmSymbols::void_method_signature(),
1969 THREAD);
1970 CLEAR_PENDING_EXCEPTION;
1971 }
1972 }
1973 // notify JVMTI
1974 if (JvmtiExport::should_post_thread_life()) {
1975 JvmtiExport::post_thread_end(this);
1976 }
1977
1978 // We have notified the agents that we are exiting, before we go on,
1979 // we must check for a pending external suspend request and honor it
1980 // in order to not surprise the thread that made the suspend request.
1981 while (true) {
1982 {
1983 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1984 if (!is_external_suspend()) {
1985 set_terminated(_thread_exiting);
1986 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
1987 break;
1988 }
1989 // Implied else:
1990 // Things get a little tricky here. We have a pending external
1991 // suspend request, but we are holding the SR_lock so we
1992 // can't just self-suspend. So we temporarily drop the lock
1993 // and then self-suspend.
1994 }
1995
1996 ThreadBlockInVM tbivm(this);
1997 java_suspend_self();
1998
1999 // We're done with this suspend request, but we have to loop around
2000 // and check again. Eventually we will get SR_lock without a pending
2001 // external suspend request and will be able to mark ourselves as
2002 // exiting.
2003 }
2004 // no more external suspends are allowed at this point
2005 } else {
2006 assert(!is_terminated() && !is_exiting(), "must not be exiting");
2007 // before_exit() has already posted JVMTI THREAD_END events
2008 }
2009
2010 if (log_is_enabled(Debug, os, thread, timer)) {
2011 _timer_exit_phase1.stop();
2012 _timer_exit_phase2.start();
2013 }
2014 // Notify waiters on thread object. This has to be done after exit() is called
2015 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
2016 // group should have the destroyed bit set before waiters are notified).
2017 ensure_join(this);
2018 assert(!this->has_pending_exception(), "ensure_join should have cleared");
2019
2020 if (log_is_enabled(Debug, os, thread, timer)) {
2021 _timer_exit_phase2.stop();
2022 _timer_exit_phase3.start();
2023 }
2024 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
2025 // held by this thread must be released. The spec does not distinguish
2026 // between JNI-acquired and regular Java monitors. We can only see
2027 // regular Java monitors here if monitor enter-exit matching is broken.
2028 //
2029 // ensure_join() ignores IllegalThreadStateExceptions, and so does
2030 // ObjectSynchronizer::release_monitors_owned_by_thread().
2031 if (exit_type == jni_detach) {
2032 // Sanity check even though JNI DetachCurrentThread() would have
2033 // returned JNI_ERR if there was a Java frame. JavaThread exit
2034 // should be done executing Java code by the time we get here.
2035 assert(!this->has_last_Java_frame(),
2036 "should not have a Java frame when detaching or exiting");
2037 ObjectSynchronizer::release_monitors_owned_by_thread(this);
2038 assert(!this->has_pending_exception(), "release_monitors should have cleared");
2039 }
2040
2041 // These things needs to be done while we are still a Java Thread. Make sure that thread
2042 // is in a consistent state, in case GC happens
2043 JFR_ONLY(Jfr::on_thread_exit(this);)
2044
2045 if (active_handles() != NULL) {
2046 JNIHandleBlock* block = active_handles();
2047 set_active_handles(NULL);
2048 JNIHandleBlock::release_block(block);
2049 }
2050
2051 if (free_handle_block() != NULL) {
2052 JNIHandleBlock* block = free_handle_block();
2053 set_free_handle_block(NULL);
2054 JNIHandleBlock::release_block(block);
2055 }
2056
2057 // These have to be removed while this is still a valid thread.
2058 remove_stack_guard_pages();
2059
2060 if (UseTLAB) {
2061 tlab().retire();
2062 }
2063
2064 if (JvmtiEnv::environments_might_exist()) {
2065 JvmtiExport::cleanup_thread(this);
2066 }
2067
2068 // We must flush any deferred card marks and other various GC barrier
2069 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2070 // before removing a thread from the list of active threads.
2071 BarrierSet::barrier_set()->on_thread_detach(this);
2072
2073 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2074 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2075 os::current_thread_id());
2076
2077 if (log_is_enabled(Debug, os, thread, timer)) {
2078 _timer_exit_phase3.stop();
2079 _timer_exit_phase4.start();
2080 }
2081 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2082 Threads::remove(this);
2083
2084 if (log_is_enabled(Debug, os, thread, timer)) {
2085 _timer_exit_phase4.stop();
2086 ResourceMark rm(this);
2087 log_debug(os, thread, timer)("name='%s'"
2088 ", exit-phase1=" JLONG_FORMAT
2089 ", exit-phase2=" JLONG_FORMAT
2090 ", exit-phase3=" JLONG_FORMAT
2091 ", exit-phase4=" JLONG_FORMAT,
2092 get_thread_name(),
2093 _timer_exit_phase1.milliseconds(),
2094 _timer_exit_phase2.milliseconds(),
2095 _timer_exit_phase3.milliseconds(),
2096 _timer_exit_phase4.milliseconds());
2097 }
2098 }
2099
2100 void JavaThread::cleanup_failed_attach_current_thread() {
2101 if (active_handles() != NULL) {
2102 JNIHandleBlock* block = active_handles();
2103 set_active_handles(NULL);
2104 JNIHandleBlock::release_block(block);
2105 }
2106
2107 if (free_handle_block() != NULL) {
2108 JNIHandleBlock* block = free_handle_block();
2109 set_free_handle_block(NULL);
2110 JNIHandleBlock::release_block(block);
2111 }
2112
2113 // These have to be removed while this is still a valid thread.
2114 remove_stack_guard_pages();
2115
2116 if (UseTLAB) {
2117 tlab().retire();
2118 }
2119
2120 BarrierSet::barrier_set()->on_thread_detach(this);
2121
2122 Threads::remove(this);
2123 this->smr_delete();
2124 }
2125
2126 JavaThread* JavaThread::active() {
2127 Thread* thread = Thread::current();
2128 if (thread->is_Java_thread()) {
2129 return (JavaThread*) thread;
2130 } else {
2131 assert(thread->is_VM_thread(), "this must be a vm thread");
2132 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2133 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2134 assert(ret->is_Java_thread(), "must be a Java thread");
2135 return ret;
2136 }
2137 }
2138
2139 bool JavaThread::is_lock_owned(address adr) const {
2140 if (Thread::is_lock_owned(adr)) return true;
2141
2142 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2143 if (chunk->contains(adr)) return true;
2144 }
2145
2146 return false;
2147 }
2148
2149
2150 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2151 chunk->set_next(monitor_chunks());
2152 set_monitor_chunks(chunk);
2153 }
2154
2155 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2156 guarantee(monitor_chunks() != NULL, "must be non empty");
2157 if (monitor_chunks() == chunk) {
2158 set_monitor_chunks(chunk->next());
2159 } else {
2160 MonitorChunk* prev = monitor_chunks();
2161 while (prev->next() != chunk) prev = prev->next();
2162 prev->set_next(chunk->next());
2163 }
2164 }
2165
2166 // JVM support.
2167
2168 // Note: this function shouldn't block if it's called in
2169 // _thread_in_native_trans state (such as from
2170 // check_special_condition_for_native_trans()).
2171 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2172
2173 if (has_last_Java_frame() && has_async_condition()) {
2174 // If we are at a polling page safepoint (not a poll return)
2175 // then we must defer async exception because live registers
2176 // will be clobbered by the exception path. Poll return is
2177 // ok because the call we a returning from already collides
2178 // with exception handling registers and so there is no issue.
2179 // (The exception handling path kills call result registers but
2180 // this is ok since the exception kills the result anyway).
2181
2182 if (is_at_poll_safepoint()) {
2183 // if the code we are returning to has deoptimized we must defer
2184 // the exception otherwise live registers get clobbered on the
2185 // exception path before deoptimization is able to retrieve them.
2186 //
2187 RegisterMap map(this, false);
2188 frame caller_fr = last_frame().sender(&map);
2189 assert(caller_fr.is_compiled_frame(), "what?");
2190 if (caller_fr.is_deoptimized_frame()) {
2191 log_info(exceptions)("deferred async exception at compiled safepoint");
2192 return;
2193 }
2194 }
2195 }
2196
2197 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2198 if (condition == _no_async_condition) {
2199 // Conditions have changed since has_special_runtime_exit_condition()
2200 // was called:
2201 // - if we were here only because of an external suspend request,
2202 // then that was taken care of above (or cancelled) so we are done
2203 // - if we were here because of another async request, then it has
2204 // been cleared between the has_special_runtime_exit_condition()
2205 // and now so again we are done
2206 return;
2207 }
2208
2209 // Check for pending async. exception
2210 if (_pending_async_exception != NULL) {
2211 // Only overwrite an already pending exception, if it is not a threadDeath.
2212 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2213
2214 // We cannot call Exceptions::_throw(...) here because we cannot block
2215 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2216
2217 LogTarget(Info, exceptions) lt;
2218 if (lt.is_enabled()) {
2219 ResourceMark rm;
2220 LogStream ls(lt);
2221 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2222 if (has_last_Java_frame()) {
2223 frame f = last_frame();
2224 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2225 }
2226 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2227 }
2228 _pending_async_exception = NULL;
2229 clear_has_async_exception();
2230 }
2231 }
2232
2233 if (check_unsafe_error &&
2234 condition == _async_unsafe_access_error && !has_pending_exception()) {
2235 condition = _no_async_condition; // done
2236 switch (thread_state()) {
2237 case _thread_in_vm: {
2238 JavaThread* THREAD = this;
2239 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2240 }
2241 case _thread_in_native: {
2242 ThreadInVMfromNative tiv(this);
2243 JavaThread* THREAD = this;
2244 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2245 }
2246 case _thread_in_Java: {
2247 ThreadInVMfromJava tiv(this);
2248 JavaThread* THREAD = this;
2249 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2250 }
2251 default:
2252 ShouldNotReachHere();
2253 }
2254 }
2255
2256 assert(condition == _no_async_condition || has_pending_exception() ||
2257 (!check_unsafe_error && condition == _async_unsafe_access_error),
2258 "must have handled the async condition, if no exception");
2259 }
2260
2261 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2262 //
2263 // Check for pending external suspend. Internal suspend requests do
2264 // not use handle_special_runtime_exit_condition().
2265 // If JNIEnv proxies are allowed, don't self-suspend if the target
2266 // thread is not the current thread. In older versions of jdbx, jdbx
2267 // threads could call into the VM with another thread's JNIEnv so we
2268 // can be here operating on behalf of a suspended thread (4432884).
2269 bool do_self_suspend = is_external_suspend_with_lock();
2270 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2271 //
2272 // Because thread is external suspended the safepoint code will count
2273 // thread as at a safepoint. This can be odd because we can be here
2274 // as _thread_in_Java which would normally transition to _thread_blocked
2275 // at a safepoint. We would like to mark the thread as _thread_blocked
2276 // before calling java_suspend_self like all other callers of it but
2277 // we must then observe proper safepoint protocol. (We can't leave
2278 // _thread_blocked with a safepoint in progress). However we can be
2279 // here as _thread_in_native_trans so we can't use a normal transition
2280 // constructor/destructor pair because they assert on that type of
2281 // transition. We could do something like:
2282 //
2283 // JavaThreadState state = thread_state();
2284 // set_thread_state(_thread_in_vm);
2285 // {
2286 // ThreadBlockInVM tbivm(this);
2287 // java_suspend_self()
2288 // }
2289 // set_thread_state(_thread_in_vm_trans);
2290 // if (safepoint) block;
2291 // set_thread_state(state);
2292 //
2293 // but that is pretty messy. Instead we just go with the way the
2294 // code has worked before and note that this is the only path to
2295 // java_suspend_self that doesn't put the thread in _thread_blocked
2296 // mode.
2297
2298 frame_anchor()->make_walkable(this);
2299 java_suspend_self();
2300
2301 // We might be here for reasons in addition to the self-suspend request
2302 // so check for other async requests.
2303 }
2304
2305 if (check_asyncs) {
2306 check_and_handle_async_exceptions();
2307 }
2308
2309 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2310 }
2311
2312 void JavaThread::send_thread_stop(oop java_throwable) {
2313 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2314 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2315 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2316
2317 // Do not throw asynchronous exceptions against the compiler thread
2318 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2319 if (!can_call_java()) return;
2320
2321 {
2322 // Actually throw the Throwable against the target Thread - however
2323 // only if there is no thread death exception installed already.
2324 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2325 // If the topmost frame is a runtime stub, then we are calling into
2326 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2327 // must deoptimize the caller before continuing, as the compiled exception handler table
2328 // may not be valid
2329 if (has_last_Java_frame()) {
2330 frame f = last_frame();
2331 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2332 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2333 RegisterMap reg_map(this, UseBiasedLocking);
2334 frame compiled_frame = f.sender(®_map);
2335 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2336 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2337 }
2338 }
2339 }
2340
2341 // Set async. pending exception in thread.
2342 set_pending_async_exception(java_throwable);
2343
2344 if (log_is_enabled(Info, exceptions)) {
2345 ResourceMark rm;
2346 log_info(exceptions)("Pending Async. exception installed of type: %s",
2347 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2348 }
2349 // for AbortVMOnException flag
2350 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2351 }
2352 }
2353
2354
2355 // Interrupt thread so it will wake up from a potential wait()
2356 Thread::interrupt(this);
2357 }
2358
2359 // External suspension mechanism.
2360 //
2361 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2362 // to any VM_locks and it is at a transition
2363 // Self-suspension will happen on the transition out of the vm.
2364 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2365 //
2366 // Guarantees on return:
2367 // + Target thread will not execute any new bytecode (that's why we need to
2368 // force a safepoint)
2369 // + Target thread will not enter any new monitors
2370 //
2371 void JavaThread::java_suspend() {
2372 ThreadsListHandle tlh;
2373 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2374 return;
2375 }
2376
2377 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2378 if (!is_external_suspend()) {
2379 // a racing resume has cancelled us; bail out now
2380 return;
2381 }
2382
2383 // suspend is done
2384 uint32_t debug_bits = 0;
2385 // Warning: is_ext_suspend_completed() may temporarily drop the
2386 // SR_lock to allow the thread to reach a stable thread state if
2387 // it is currently in a transient thread state.
2388 if (is_ext_suspend_completed(false /* !called_by_wait */,
2389 SuspendRetryDelay, &debug_bits)) {
2390 return;
2391 }
2392 }
2393
2394 if (Thread::current() == this) {
2395 // Safely self-suspend.
2396 // If we don't do this explicitly it will implicitly happen
2397 // before we transition back to Java, and on some other thread-state
2398 // transition paths, but not as we exit a JVM TI SuspendThread call.
2399 // As SuspendThread(current) must not return (until resumed) we must
2400 // self-suspend here.
2401 ThreadBlockInVM tbivm(this);
2402 java_suspend_self();
2403 } else {
2404 VM_ThreadSuspend vm_suspend;
2405 VMThread::execute(&vm_suspend);
2406 }
2407 }
2408
2409 // Part II of external suspension.
2410 // A JavaThread self suspends when it detects a pending external suspend
2411 // request. This is usually on transitions. It is also done in places
2412 // where continuing to the next transition would surprise the caller,
2413 // e.g., monitor entry.
2414 //
2415 // Returns the number of times that the thread self-suspended.
2416 //
2417 // Note: DO NOT call java_suspend_self() when you just want to block current
2418 // thread. java_suspend_self() is the second stage of cooperative
2419 // suspension for external suspend requests and should only be used
2420 // to complete an external suspend request.
2421 //
2422 int JavaThread::java_suspend_self() {
2423 int ret = 0;
2424
2425 // we are in the process of exiting so don't suspend
2426 if (is_exiting()) {
2427 clear_external_suspend();
2428 return ret;
2429 }
2430
2431 assert(_anchor.walkable() ||
2432 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2433 "must have walkable stack");
2434
2435 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2436
2437 assert(!this->is_ext_suspended(),
2438 "a thread trying to self-suspend should not already be suspended");
2439
2440 if (this->is_suspend_equivalent()) {
2441 // If we are self-suspending as a result of the lifting of a
2442 // suspend equivalent condition, then the suspend_equivalent
2443 // flag is not cleared until we set the ext_suspended flag so
2444 // that wait_for_ext_suspend_completion() returns consistent
2445 // results.
2446 this->clear_suspend_equivalent();
2447 }
2448
2449 // A racing resume may have cancelled us before we grabbed SR_lock
2450 // above. Or another external suspend request could be waiting for us
2451 // by the time we return from SR_lock()->wait(). The thread
2452 // that requested the suspension may already be trying to walk our
2453 // stack and if we return now, we can change the stack out from under
2454 // it. This would be a "bad thing (TM)" and cause the stack walker
2455 // to crash. We stay self-suspended until there are no more pending
2456 // external suspend requests.
2457 while (is_external_suspend()) {
2458 ret++;
2459 this->set_ext_suspended();
2460
2461 // _ext_suspended flag is cleared by java_resume()
2462 while (is_ext_suspended()) {
2463 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2464 }
2465 }
2466
2467 return ret;
2468 }
2469
2470 #ifdef ASSERT
2471 // Verify the JavaThread has not yet been published in the Threads::list, and
2472 // hence doesn't need protection from concurrent access at this stage.
2473 void JavaThread::verify_not_published() {
2474 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2475 // since an unpublished JavaThread doesn't participate in the
2476 // Thread-SMR protocol for keeping a ThreadsList alive.
2477 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2478 }
2479 #endif
2480
2481 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2482 // progress or when _suspend_flags is non-zero.
2483 // Current thread needs to self-suspend if there is a suspend request and/or
2484 // block if a safepoint is in progress.
2485 // Async exception ISN'T checked.
2486 // Note only the ThreadInVMfromNative transition can call this function
2487 // directly and when thread state is _thread_in_native_trans
2488 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2489 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2490
2491 JavaThread *curJT = JavaThread::current();
2492 bool do_self_suspend = thread->is_external_suspend();
2493
2494 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2495
2496 // If JNIEnv proxies are allowed, don't self-suspend if the target
2497 // thread is not the current thread. In older versions of jdbx, jdbx
2498 // threads could call into the VM with another thread's JNIEnv so we
2499 // can be here operating on behalf of a suspended thread (4432884).
2500 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2501 JavaThreadState state = thread->thread_state();
2502
2503 // We mark this thread_blocked state as a suspend-equivalent so
2504 // that a caller to is_ext_suspend_completed() won't be confused.
2505 // The suspend-equivalent state is cleared by java_suspend_self().
2506 thread->set_suspend_equivalent();
2507
2508 // If the safepoint code sees the _thread_in_native_trans state, it will
2509 // wait until the thread changes to other thread state. There is no
2510 // guarantee on how soon we can obtain the SR_lock and complete the
2511 // self-suspend request. It would be a bad idea to let safepoint wait for
2512 // too long. Temporarily change the state to _thread_blocked to
2513 // let the VM thread know that this thread is ready for GC. The problem
2514 // of changing thread state is that safepoint could happen just after
2515 // java_suspend_self() returns after being resumed, and VM thread will
2516 // see the _thread_blocked state. We must check for safepoint
2517 // after restoring the state and make sure we won't leave while a safepoint
2518 // is in progress.
2519 thread->set_thread_state(_thread_blocked);
2520 thread->java_suspend_self();
2521 thread->set_thread_state(state);
2522
2523 InterfaceSupport::serialize_thread_state_with_handler(thread);
2524 }
2525
2526 SafepointMechanism::block_if_requested(curJT);
2527
2528 if (thread->is_deopt_suspend()) {
2529 thread->clear_deopt_suspend();
2530 RegisterMap map(thread, false);
2531 frame f = thread->last_frame();
2532 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2533 f = f.sender(&map);
2534 }
2535 if (f.id() == thread->must_deopt_id()) {
2536 thread->clear_must_deopt_id();
2537 f.deoptimize(thread);
2538 } else {
2539 fatal("missed deoptimization!");
2540 }
2541 }
2542
2543 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2544 }
2545
2546 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2547 // progress or when _suspend_flags is non-zero.
2548 // Current thread needs to self-suspend if there is a suspend request and/or
2549 // block if a safepoint is in progress.
2550 // Also check for pending async exception (not including unsafe access error).
2551 // Note only the native==>VM/Java barriers can call this function and when
2552 // thread state is _thread_in_native_trans.
2553 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2554 check_safepoint_and_suspend_for_native_trans(thread);
2555
2556 if (thread->has_async_exception()) {
2557 // We are in _thread_in_native_trans state, don't handle unsafe
2558 // access error since that may block.
2559 thread->check_and_handle_async_exceptions(false);
2560 }
2561 }
2562
2563 // This is a variant of the normal
2564 // check_special_condition_for_native_trans with slightly different
2565 // semantics for use by critical native wrappers. It does all the
2566 // normal checks but also performs the transition back into
2567 // thread_in_Java state. This is required so that critical natives
2568 // can potentially block and perform a GC if they are the last thread
2569 // exiting the GCLocker.
2570 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2571 check_special_condition_for_native_trans(thread);
2572
2573 // Finish the transition
2574 thread->set_thread_state(_thread_in_Java);
2575
2576 if (thread->do_critical_native_unlock()) {
2577 ThreadInVMfromJavaNoAsyncException tiv(thread);
2578 GCLocker::unlock_critical(thread);
2579 thread->clear_critical_native_unlock();
2580 }
2581 }
2582
2583 // We need to guarantee the Threads_lock here, since resumes are not
2584 // allowed during safepoint synchronization
2585 // Can only resume from an external suspension
2586 void JavaThread::java_resume() {
2587 assert_locked_or_safepoint(Threads_lock);
2588
2589 // Sanity check: thread is gone, has started exiting or the thread
2590 // was not externally suspended.
2591 ThreadsListHandle tlh;
2592 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2593 return;
2594 }
2595
2596 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2597
2598 clear_external_suspend();
2599
2600 if (is_ext_suspended()) {
2601 clear_ext_suspended();
2602 SR_lock()->notify_all();
2603 }
2604 }
2605
2606 size_t JavaThread::_stack_red_zone_size = 0;
2607 size_t JavaThread::_stack_yellow_zone_size = 0;
2608 size_t JavaThread::_stack_reserved_zone_size = 0;
2609 size_t JavaThread::_stack_shadow_zone_size = 0;
2610
2611 void JavaThread::create_stack_guard_pages() {
2612 if (!os::uses_stack_guard_pages() ||
2613 _stack_guard_state != stack_guard_unused ||
2614 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2615 log_info(os, thread)("Stack guard page creation for thread "
2616 UINTX_FORMAT " disabled", os::current_thread_id());
2617 return;
2618 }
2619 address low_addr = stack_end();
2620 size_t len = stack_guard_zone_size();
2621
2622 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2623 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2624
2625 int must_commit = os::must_commit_stack_guard_pages();
2626 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2627
2628 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2629 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2630 return;
2631 }
2632
2633 if (os::guard_memory((char *) low_addr, len)) {
2634 _stack_guard_state = stack_guard_enabled;
2635 } else {
2636 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2637 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2638 if (os::uncommit_memory((char *) low_addr, len)) {
2639 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2640 }
2641 return;
2642 }
2643
2644 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2645 PTR_FORMAT "-" PTR_FORMAT ".",
2646 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2647 }
2648
2649 void JavaThread::remove_stack_guard_pages() {
2650 assert(Thread::current() == this, "from different thread");
2651 if (_stack_guard_state == stack_guard_unused) return;
2652 address low_addr = stack_end();
2653 size_t len = stack_guard_zone_size();
2654
2655 if (os::must_commit_stack_guard_pages()) {
2656 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2657 _stack_guard_state = stack_guard_unused;
2658 } else {
2659 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2660 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2661 return;
2662 }
2663 } else {
2664 if (_stack_guard_state == stack_guard_unused) return;
2665 if (os::unguard_memory((char *) low_addr, len)) {
2666 _stack_guard_state = stack_guard_unused;
2667 } else {
2668 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2669 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2670 return;
2671 }
2672 }
2673
2674 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2675 PTR_FORMAT "-" PTR_FORMAT ".",
2676 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2677 }
2678
2679 void JavaThread::enable_stack_reserved_zone() {
2680 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state");
2681
2682 // The base notation is from the stack's point of view, growing downward.
2683 // We need to adjust it to work correctly with guard_memory()
2684 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2685
2686 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2687 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2688
2689 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2690 _stack_guard_state = stack_guard_enabled;
2691 } else {
2692 warning("Attempt to guard stack reserved zone failed.");
2693 }
2694 enable_register_stack_guard();
2695 }
2696
2697 void JavaThread::disable_stack_reserved_zone() {
2698 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state");
2699
2700 // Simply return if called for a thread that does not use guard pages.
2701 if (_stack_guard_state != stack_guard_enabled) return;
2702
2703 // The base notation is from the stack's point of view, growing downward.
2704 // We need to adjust it to work correctly with guard_memory()
2705 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2706
2707 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2708 _stack_guard_state = stack_guard_reserved_disabled;
2709 } else {
2710 warning("Attempt to unguard stack reserved zone failed.");
2711 }
2712 disable_register_stack_guard();
2713 }
2714
2715 void JavaThread::enable_stack_yellow_reserved_zone() {
2716 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2717 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2718
2719 // The base notation is from the stacks point of view, growing downward.
2720 // We need to adjust it to work correctly with guard_memory()
2721 address base = stack_red_zone_base();
2722
2723 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2724 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2725
2726 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2727 _stack_guard_state = stack_guard_enabled;
2728 } else {
2729 warning("Attempt to guard stack yellow zone failed.");
2730 }
2731 enable_register_stack_guard();
2732 }
2733
2734 void JavaThread::disable_stack_yellow_reserved_zone() {
2735 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2736 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2737
2738 // Simply return if called for a thread that does not use guard pages.
2739 if (_stack_guard_state == stack_guard_unused) return;
2740
2741 // The base notation is from the stacks point of view, growing downward.
2742 // We need to adjust it to work correctly with guard_memory()
2743 address base = stack_red_zone_base();
2744
2745 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2746 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2747 } else {
2748 warning("Attempt to unguard stack yellow zone failed.");
2749 }
2750 disable_register_stack_guard();
2751 }
2752
2753 void JavaThread::enable_stack_red_zone() {
2754 // The base notation is from the stacks point of view, growing downward.
2755 // We need to adjust it to work correctly with guard_memory()
2756 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2757 address base = stack_red_zone_base() - stack_red_zone_size();
2758
2759 guarantee(base < stack_base(), "Error calculating stack red zone");
2760 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2761
2762 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2763 warning("Attempt to guard stack red zone failed.");
2764 }
2765 }
2766
2767 void JavaThread::disable_stack_red_zone() {
2768 // The base notation is from the stacks point of view, growing downward.
2769 // We need to adjust it to work correctly with guard_memory()
2770 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2771 address base = stack_red_zone_base() - stack_red_zone_size();
2772 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2773 warning("Attempt to unguard stack red zone failed.");
2774 }
2775 }
2776
2777 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2778 // ignore is there is no stack
2779 if (!has_last_Java_frame()) return;
2780 // traverse the stack frames. Starts from top frame.
2781 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2782 frame* fr = fst.current();
2783 f(fr, fst.register_map());
2784 }
2785 }
2786
2787
2788 #ifndef PRODUCT
2789 // Deoptimization
2790 // Function for testing deoptimization
2791 void JavaThread::deoptimize() {
2792 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2793 StackFrameStream fst(this, UseBiasedLocking);
2794 bool deopt = false; // Dump stack only if a deopt actually happens.
2795 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2796 // Iterate over all frames in the thread and deoptimize
2797 for (; !fst.is_done(); fst.next()) {
2798 if (fst.current()->can_be_deoptimized()) {
2799
2800 if (only_at) {
2801 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2802 // consists of comma or carriage return separated numbers so
2803 // search for the current bci in that string.
2804 address pc = fst.current()->pc();
2805 nmethod* nm = (nmethod*) fst.current()->cb();
2806 ScopeDesc* sd = nm->scope_desc_at(pc);
2807 char buffer[8];
2808 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2809 size_t len = strlen(buffer);
2810 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2811 while (found != NULL) {
2812 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2813 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2814 // Check that the bci found is bracketed by terminators.
2815 break;
2816 }
2817 found = strstr(found + 1, buffer);
2818 }
2819 if (!found) {
2820 continue;
2821 }
2822 }
2823
2824 if (DebugDeoptimization && !deopt) {
2825 deopt = true; // One-time only print before deopt
2826 tty->print_cr("[BEFORE Deoptimization]");
2827 trace_frames();
2828 trace_stack();
2829 }
2830 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2831 }
2832 }
2833
2834 if (DebugDeoptimization && deopt) {
2835 tty->print_cr("[AFTER Deoptimization]");
2836 trace_frames();
2837 }
2838 }
2839
2840
2841 // Make zombies
2842 void JavaThread::make_zombies() {
2843 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2844 if (fst.current()->can_be_deoptimized()) {
2845 // it is a Java nmethod
2846 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2847 nm->make_not_entrant();
2848 }
2849 }
2850 }
2851 #endif // PRODUCT
2852
2853
2854 void JavaThread::deoptimized_wrt_marked_nmethods() {
2855 if (!has_last_Java_frame()) return;
2856 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2857 StackFrameStream fst(this, UseBiasedLocking);
2858 for (; !fst.is_done(); fst.next()) {
2859 if (fst.current()->should_be_deoptimized()) {
2860 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2861 }
2862 }
2863 }
2864
2865
2866 // If the caller is a NamedThread, then remember, in the current scope,
2867 // the given JavaThread in its _processed_thread field.
2868 class RememberProcessedThread: public StackObj {
2869 NamedThread* _cur_thr;
2870 public:
2871 RememberProcessedThread(JavaThread* jthr) {
2872 Thread* thread = Thread::current();
2873 if (thread->is_Named_thread()) {
2874 _cur_thr = (NamedThread *)thread;
2875 _cur_thr->set_processed_thread(jthr);
2876 } else {
2877 _cur_thr = NULL;
2878 }
2879 }
2880
2881 ~RememberProcessedThread() {
2882 if (_cur_thr) {
2883 _cur_thr->set_processed_thread(NULL);
2884 }
2885 }
2886 };
2887
2888 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2889 // Verify that the deferred card marks have been flushed.
2890 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2891
2892 // Traverse the GCHandles
2893 Thread::oops_do(f, cf);
2894
2895 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2896 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2897
2898 if (has_last_Java_frame()) {
2899 // Record JavaThread to GC thread
2900 RememberProcessedThread rpt(this);
2901
2902 // traverse the registered growable array
2903 if (_array_for_gc != NULL) {
2904 for (int index = 0; index < _array_for_gc->length(); index++) {
2905 f->do_oop(_array_for_gc->adr_at(index));
2906 }
2907 }
2908
2909 // Traverse the monitor chunks
2910 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2911 chunk->oops_do(f);
2912 }
2913
2914 // Traverse the execution stack
2915 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2916 fst.current()->oops_do(f, cf, fst.register_map());
2917 }
2918 }
2919
2920 // callee_target is never live across a gc point so NULL it here should
2921 // it still contain a methdOop.
2922
2923 set_callee_target(NULL);
2924
2925 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2926 // If we have deferred set_locals there might be oops waiting to be
2927 // written
2928 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2929 if (list != NULL) {
2930 for (int i = 0; i < list->length(); i++) {
2931 list->at(i)->oops_do(f);
2932 }
2933 }
2934
2935 // Traverse instance variables at the end since the GC may be moving things
2936 // around using this function
2937 f->do_oop((oop*) &_threadObj);
2938 f->do_oop((oop*) &_vm_result);
2939 f->do_oop((oop*) &_exception_oop);
2940 f->do_oop((oop*) &_pending_async_exception);
2941
2942 if (jvmti_thread_state() != NULL) {
2943 jvmti_thread_state()->oops_do(f);
2944 }
2945 }
2946
2947 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2948 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2949 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2950
2951 if (has_last_Java_frame()) {
2952 // Traverse the execution stack
2953 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2954 fst.current()->nmethods_do(cf);
2955 }
2956 }
2957 }
2958
2959 void JavaThread::metadata_do(void f(Metadata*)) {
2960 if (has_last_Java_frame()) {
2961 // Traverse the execution stack to call f() on the methods in the stack
2962 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2963 fst.current()->metadata_do(f);
2964 }
2965 } else if (is_Compiler_thread()) {
2966 // need to walk ciMetadata in current compile tasks to keep alive.
2967 CompilerThread* ct = (CompilerThread*)this;
2968 if (ct->env() != NULL) {
2969 ct->env()->metadata_do(f);
2970 }
2971 CompileTask* task = ct->task();
2972 if (task != NULL) {
2973 task->metadata_do(f);
2974 }
2975 }
2976 }
2977
2978 // Printing
2979 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2980 switch (_thread_state) {
2981 case _thread_uninitialized: return "_thread_uninitialized";
2982 case _thread_new: return "_thread_new";
2983 case _thread_new_trans: return "_thread_new_trans";
2984 case _thread_in_native: return "_thread_in_native";
2985 case _thread_in_native_trans: return "_thread_in_native_trans";
2986 case _thread_in_vm: return "_thread_in_vm";
2987 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2988 case _thread_in_Java: return "_thread_in_Java";
2989 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2990 case _thread_blocked: return "_thread_blocked";
2991 case _thread_blocked_trans: return "_thread_blocked_trans";
2992 default: return "unknown thread state";
2993 }
2994 }
2995
2996 #ifndef PRODUCT
2997 void JavaThread::print_thread_state_on(outputStream *st) const {
2998 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2999 };
3000 void JavaThread::print_thread_state() const {
3001 print_thread_state_on(tty);
3002 }
3003 #endif // PRODUCT
3004
3005 // Called by Threads::print() for VM_PrintThreads operation
3006 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
3007 st->print_raw("\"");
3008 st->print_raw(get_thread_name());
3009 st->print_raw("\" ");
3010 oop thread_oop = threadObj();
3011 if (thread_oop != NULL) {
3012 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
3013 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
3014 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
3015 }
3016 Thread::print_on(st, print_extended_info);
3017 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
3018 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
3019 if (thread_oop != NULL) {
3020 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3021 }
3022 #ifndef PRODUCT
3023 _safepoint_state->print_on(st);
3024 #endif // PRODUCT
3025 if (is_Compiler_thread()) {
3026 CompileTask *task = ((CompilerThread*)this)->task();
3027 if (task != NULL) {
3028 st->print(" Compiling: ");
3029 task->print(st, NULL, true, false);
3030 } else {
3031 st->print(" No compile task");
3032 }
3033 st->cr();
3034 }
3035 }
3036
3037 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3038 st->print("%s", get_thread_name_string(buf, buflen));
3039 }
3040
3041 // Called by fatal error handler. The difference between this and
3042 // JavaThread::print() is that we can't grab lock or allocate memory.
3043 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3044 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3045 oop thread_obj = threadObj();
3046 if (thread_obj != NULL) {
3047 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3048 }
3049 st->print(" [");
3050 st->print("%s", _get_thread_state_name(_thread_state));
3051 if (osthread()) {
3052 st->print(", id=%d", osthread()->thread_id());
3053 }
3054 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3055 p2i(stack_end()), p2i(stack_base()));
3056 st->print("]");
3057
3058 ThreadsSMRSupport::print_info_on(this, st);
3059 return;
3060 }
3061
3062 // Verification
3063
3064 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3065
3066 void JavaThread::verify() {
3067 // Verify oops in the thread.
3068 oops_do(&VerifyOopClosure::verify_oop, NULL);
3069
3070 // Verify the stack frames.
3071 frames_do(frame_verify);
3072 }
3073
3074 // CR 6300358 (sub-CR 2137150)
3075 // Most callers of this method assume that it can't return NULL but a
3076 // thread may not have a name whilst it is in the process of attaching to
3077 // the VM - see CR 6412693, and there are places where a JavaThread can be
3078 // seen prior to having it's threadObj set (eg JNI attaching threads and
3079 // if vm exit occurs during initialization). These cases can all be accounted
3080 // for such that this method never returns NULL.
3081 const char* JavaThread::get_thread_name() const {
3082 #ifdef ASSERT
3083 // early safepoints can hit while current thread does not yet have TLS
3084 if (!SafepointSynchronize::is_at_safepoint()) {
3085 Thread *cur = Thread::current();
3086 if (!(cur->is_Java_thread() && cur == this)) {
3087 // Current JavaThreads are allowed to get their own name without
3088 // the Threads_lock.
3089 assert_locked_or_safepoint(Threads_lock);
3090 }
3091 }
3092 #endif // ASSERT
3093 return get_thread_name_string();
3094 }
3095
3096 // Returns a non-NULL representation of this thread's name, or a suitable
3097 // descriptive string if there is no set name
3098 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3099 const char* name_str;
3100 oop thread_obj = threadObj();
3101 if (thread_obj != NULL) {
3102 oop name = java_lang_Thread::name(thread_obj);
3103 if (name != NULL) {
3104 if (buf == NULL) {
3105 name_str = java_lang_String::as_utf8_string(name);
3106 } else {
3107 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3108 }
3109 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3110 name_str = "<no-name - thread is attaching>";
3111 } else {
3112 name_str = Thread::name();
3113 }
3114 } else {
3115 name_str = Thread::name();
3116 }
3117 assert(name_str != NULL, "unexpected NULL thread name");
3118 return name_str;
3119 }
3120
3121
3122 const char* JavaThread::get_threadgroup_name() const {
3123 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3124 oop thread_obj = threadObj();
3125 if (thread_obj != NULL) {
3126 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3127 if (thread_group != NULL) {
3128 // ThreadGroup.name can be null
3129 return java_lang_ThreadGroup::name(thread_group);
3130 }
3131 }
3132 return NULL;
3133 }
3134
3135 const char* JavaThread::get_parent_name() const {
3136 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3137 oop thread_obj = threadObj();
3138 if (thread_obj != NULL) {
3139 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3140 if (thread_group != NULL) {
3141 oop parent = java_lang_ThreadGroup::parent(thread_group);
3142 if (parent != NULL) {
3143 // ThreadGroup.name can be null
3144 return java_lang_ThreadGroup::name(parent);
3145 }
3146 }
3147 }
3148 return NULL;
3149 }
3150
3151 ThreadPriority JavaThread::java_priority() const {
3152 oop thr_oop = threadObj();
3153 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3154 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3155 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3156 return priority;
3157 }
3158
3159 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3160
3161 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3162 // Link Java Thread object <-> C++ Thread
3163
3164 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3165 // and put it into a new Handle. The Handle "thread_oop" can then
3166 // be used to pass the C++ thread object to other methods.
3167
3168 // Set the Java level thread object (jthread) field of the
3169 // new thread (a JavaThread *) to C++ thread object using the
3170 // "thread_oop" handle.
3171
3172 // Set the thread field (a JavaThread *) of the
3173 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3174
3175 Handle thread_oop(Thread::current(),
3176 JNIHandles::resolve_non_null(jni_thread));
3177 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3178 "must be initialized");
3179 set_threadObj(thread_oop());
3180 java_lang_Thread::set_thread(thread_oop(), this);
3181
3182 if (prio == NoPriority) {
3183 prio = java_lang_Thread::priority(thread_oop());
3184 assert(prio != NoPriority, "A valid priority should be present");
3185 }
3186
3187 // Push the Java priority down to the native thread; needs Threads_lock
3188 Thread::set_priority(this, prio);
3189
3190 // Add the new thread to the Threads list and set it in motion.
3191 // We must have threads lock in order to call Threads::add.
3192 // It is crucial that we do not block before the thread is
3193 // added to the Threads list for if a GC happens, then the java_thread oop
3194 // will not be visited by GC.
3195 Threads::add(this);
3196 }
3197
3198 oop JavaThread::current_park_blocker() {
3199 // Support for JSR-166 locks
3200 oop thread_oop = threadObj();
3201 if (thread_oop != NULL &&
3202 JDK_Version::current().supports_thread_park_blocker()) {
3203 return java_lang_Thread::park_blocker(thread_oop);
3204 }
3205 return NULL;
3206 }
3207
3208
3209 void JavaThread::print_stack_on(outputStream* st) {
3210 if (!has_last_Java_frame()) return;
3211 ResourceMark rm;
3212 HandleMark hm;
3213
3214 RegisterMap reg_map(this);
3215 vframe* start_vf = last_java_vframe(®_map);
3216 int count = 0;
3217 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3218 if (f->is_java_frame()) {
3219 javaVFrame* jvf = javaVFrame::cast(f);
3220 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3221
3222 // Print out lock information
3223 if (JavaMonitorsInStackTrace) {
3224 jvf->print_lock_info_on(st, count);
3225 }
3226 } else {
3227 // Ignore non-Java frames
3228 }
3229
3230 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3231 count++;
3232 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3233 }
3234 }
3235
3236
3237 // JVMTI PopFrame support
3238 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3239 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3240 if (in_bytes(size_in_bytes) != 0) {
3241 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3242 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3243 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3244 }
3245 }
3246
3247 void* JavaThread::popframe_preserved_args() {
3248 return _popframe_preserved_args;
3249 }
3250
3251 ByteSize JavaThread::popframe_preserved_args_size() {
3252 return in_ByteSize(_popframe_preserved_args_size);
3253 }
3254
3255 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3256 int sz = in_bytes(popframe_preserved_args_size());
3257 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3258 return in_WordSize(sz / wordSize);
3259 }
3260
3261 void JavaThread::popframe_free_preserved_args() {
3262 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3263 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3264 _popframe_preserved_args = NULL;
3265 _popframe_preserved_args_size = 0;
3266 }
3267
3268 #ifndef PRODUCT
3269
3270 void JavaThread::trace_frames() {
3271 tty->print_cr("[Describe stack]");
3272 int frame_no = 1;
3273 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3274 tty->print(" %d. ", frame_no++);
3275 fst.current()->print_value_on(tty, this);
3276 tty->cr();
3277 }
3278 }
3279
3280 class PrintAndVerifyOopClosure: public OopClosure {
3281 protected:
3282 template <class T> inline void do_oop_work(T* p) {
3283 oop obj = RawAccess<>::oop_load(p);
3284 if (obj == NULL) return;
3285 tty->print(INTPTR_FORMAT ": ", p2i(p));
3286 if (oopDesc::is_oop_or_null(obj)) {
3287 if (obj->is_objArray()) {
3288 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3289 } else {
3290 obj->print();
3291 }
3292 } else {
3293 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3294 }
3295 tty->cr();
3296 }
3297 public:
3298 virtual void do_oop(oop* p) { do_oop_work(p); }
3299 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3300 };
3301
3302
3303 static void oops_print(frame* f, const RegisterMap *map) {
3304 PrintAndVerifyOopClosure print;
3305 f->print_value();
3306 f->oops_do(&print, NULL, (RegisterMap*)map);
3307 }
3308
3309 // Print our all the locations that contain oops and whether they are
3310 // valid or not. This useful when trying to find the oldest frame
3311 // where an oop has gone bad since the frame walk is from youngest to
3312 // oldest.
3313 void JavaThread::trace_oops() {
3314 tty->print_cr("[Trace oops]");
3315 frames_do(oops_print);
3316 }
3317
3318
3319 #ifdef ASSERT
3320 // Print or validate the layout of stack frames
3321 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3322 ResourceMark rm;
3323 PRESERVE_EXCEPTION_MARK;
3324 FrameValues values;
3325 int frame_no = 0;
3326 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3327 fst.current()->describe(values, ++frame_no);
3328 if (depth == frame_no) break;
3329 }
3330 if (validate_only) {
3331 values.validate();
3332 } else {
3333 tty->print_cr("[Describe stack layout]");
3334 values.print(this);
3335 }
3336 }
3337 #endif
3338
3339 void JavaThread::trace_stack_from(vframe* start_vf) {
3340 ResourceMark rm;
3341 int vframe_no = 1;
3342 for (vframe* f = start_vf; f; f = f->sender()) {
3343 if (f->is_java_frame()) {
3344 javaVFrame::cast(f)->print_activation(vframe_no++);
3345 } else {
3346 f->print();
3347 }
3348 if (vframe_no > StackPrintLimit) {
3349 tty->print_cr("...<more frames>...");
3350 return;
3351 }
3352 }
3353 }
3354
3355
3356 void JavaThread::trace_stack() {
3357 if (!has_last_Java_frame()) return;
3358 ResourceMark rm;
3359 HandleMark hm;
3360 RegisterMap reg_map(this);
3361 trace_stack_from(last_java_vframe(®_map));
3362 }
3363
3364
3365 #endif // PRODUCT
3366
3367
3368 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3369 assert(reg_map != NULL, "a map must be given");
3370 frame f = last_frame();
3371 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3372 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3373 }
3374 return NULL;
3375 }
3376
3377
3378 Klass* JavaThread::security_get_caller_class(int depth) {
3379 vframeStream vfst(this);
3380 vfst.security_get_caller_frame(depth);
3381 if (!vfst.at_end()) {
3382 return vfst.method()->method_holder();
3383 }
3384 return NULL;
3385 }
3386
3387 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3388 assert(thread->is_Compiler_thread(), "must be compiler thread");
3389 CompileBroker::compiler_thread_loop();
3390 }
3391
3392 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3393 NMethodSweeper::sweeper_loop();
3394 }
3395
3396 // Create a CompilerThread
3397 CompilerThread::CompilerThread(CompileQueue* queue,
3398 CompilerCounters* counters)
3399 : JavaThread(&compiler_thread_entry) {
3400 _env = NULL;
3401 _log = NULL;
3402 _task = NULL;
3403 _queue = queue;
3404 _counters = counters;
3405 _buffer_blob = NULL;
3406 _compiler = NULL;
3407
3408 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3409 resource_area()->bias_to(mtCompiler);
3410
3411 #ifndef PRODUCT
3412 _ideal_graph_printer = NULL;
3413 #endif
3414 }
3415
3416 CompilerThread::~CompilerThread() {
3417 // Delete objects which were allocated on heap.
3418 delete _counters;
3419 }
3420
3421 bool CompilerThread::can_call_java() const {
3422 return _compiler != NULL && _compiler->is_jvmci();
3423 }
3424
3425 // Create sweeper thread
3426 CodeCacheSweeperThread::CodeCacheSweeperThread()
3427 : JavaThread(&sweeper_thread_entry) {
3428 _scanned_compiled_method = NULL;
3429 }
3430
3431 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3432 JavaThread::oops_do(f, cf);
3433 if (_scanned_compiled_method != NULL && cf != NULL) {
3434 // Safepoints can occur when the sweeper is scanning an nmethod so
3435 // process it here to make sure it isn't unloaded in the middle of
3436 // a scan.
3437 cf->do_code_blob(_scanned_compiled_method);
3438 }
3439 }
3440
3441 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3442 JavaThread::nmethods_do(cf);
3443 if (_scanned_compiled_method != NULL && cf != NULL) {
3444 // Safepoints can occur when the sweeper is scanning an nmethod so
3445 // process it here to make sure it isn't unloaded in the middle of
3446 // a scan.
3447 cf->do_code_blob(_scanned_compiled_method);
3448 }
3449 }
3450
3451
3452 // ======= Threads ========
3453
3454 // The Threads class links together all active threads, and provides
3455 // operations over all threads. It is protected by the Threads_lock,
3456 // which is also used in other global contexts like safepointing.
3457 // ThreadsListHandles are used to safely perform operations on one
3458 // or more threads without the risk of the thread exiting during the
3459 // operation.
3460 //
3461 // Note: The Threads_lock is currently more widely used than we
3462 // would like. We are actively migrating Threads_lock uses to other
3463 // mechanisms in order to reduce Threads_lock contention.
3464
3465 JavaThread* Threads::_thread_list = NULL;
3466 int Threads::_number_of_threads = 0;
3467 int Threads::_number_of_non_daemon_threads = 0;
3468 int Threads::_return_code = 0;
3469 int Threads::_thread_claim_parity = 0;
3470 size_t JavaThread::_stack_size_at_create = 0;
3471
3472 #ifdef ASSERT
3473 bool Threads::_vm_complete = false;
3474 #endif
3475
3476 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3477 Prefetch::read((void*)addr, prefetch_interval);
3478 return *addr;
3479 }
3480
3481 // Possibly the ugliest for loop the world has seen. C++ does not allow
3482 // multiple types in the declaration section of the for loop. In this case
3483 // we are only dealing with pointers and hence can cast them. It looks ugly
3484 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3485 #define DO_JAVA_THREADS(LIST, X) \
3486 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3487 *MACRO_list = (JavaThread*)(LIST), \
3488 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3489 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3490 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3491 MACRO_current_p != MACRO_end; \
3492 MACRO_current_p++, \
3493 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3494
3495 // All JavaThreads
3496 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3497
3498 // All NonJavaThreads (i.e., every non-JavaThread in the system).
3499 void Threads::non_java_threads_do(ThreadClosure* tc) {
3500 NoSafepointVerifier nsv(!SafepointSynchronize::is_at_safepoint(), false);
3501 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
3502 tc->do_thread(njti.current());
3503 }
3504 }
3505
3506 // All JavaThreads
3507 void Threads::java_threads_do(ThreadClosure* tc) {
3508 assert_locked_or_safepoint(Threads_lock);
3509 // ALL_JAVA_THREADS iterates through all JavaThreads.
3510 ALL_JAVA_THREADS(p) {
3511 tc->do_thread(p);
3512 }
3513 }
3514
3515 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3516 assert_locked_or_safepoint(Threads_lock);
3517 java_threads_do(tc);
3518 tc->do_thread(VMThread::vm_thread());
3519 }
3520
3521 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3522 void Threads::threads_do(ThreadClosure* tc) {
3523 assert_locked_or_safepoint(Threads_lock);
3524 java_threads_do(tc);
3525 non_java_threads_do(tc);
3526 }
3527
3528 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3529 int cp = Threads::thread_claim_parity();
3530 ALL_JAVA_THREADS(p) {
3531 if (p->claim_oops_do(is_par, cp)) {
3532 tc->do_thread(p);
3533 }
3534 }
3535 VMThread* vmt = VMThread::vm_thread();
3536 if (vmt->claim_oops_do(is_par, cp)) {
3537 tc->do_thread(vmt);
3538 }
3539 }
3540
3541 // The system initialization in the library has three phases.
3542 //
3543 // Phase 1: java.lang.System class initialization
3544 // java.lang.System is a primordial class loaded and initialized
3545 // by the VM early during startup. java.lang.System.<clinit>
3546 // only does registerNatives and keeps the rest of the class
3547 // initialization work later until thread initialization completes.
3548 //
3549 // System.initPhase1 initializes the system properties, the static
3550 // fields in, out, and err. Set up java signal handlers, OS-specific
3551 // system settings, and thread group of the main thread.
3552 static void call_initPhase1(TRAPS) {
3553 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3554 JavaValue result(T_VOID);
3555 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3556 vmSymbols::void_method_signature(), CHECK);
3557 }
3558
3559 // Phase 2. Module system initialization
3560 // This will initialize the module system. Only java.base classes
3561 // can be loaded until phase 2 completes.
3562 //
3563 // Call System.initPhase2 after the compiler initialization and jsr292
3564 // classes get initialized because module initialization runs a lot of java
3565 // code, that for performance reasons, should be compiled. Also, this will
3566 // enable the startup code to use lambda and other language features in this
3567 // phase and onward.
3568 //
3569 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3570 static void call_initPhase2(TRAPS) {
3571 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3572
3573 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3574
3575 JavaValue result(T_INT);
3576 JavaCallArguments args;
3577 args.push_int(DisplayVMOutputToStderr);
3578 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3579 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3580 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3581 if (result.get_jint() != JNI_OK) {
3582 vm_exit_during_initialization(); // no message or exception
3583 }
3584
3585 universe_post_module_init();
3586 }
3587
3588 // Phase 3. final setup - set security manager, system class loader and TCCL
3589 //
3590 // This will instantiate and set the security manager, set the system class
3591 // loader as well as the thread context class loader. The security manager
3592 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3593 // other modules or the application's classpath.
3594 static void call_initPhase3(TRAPS) {
3595 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3596 JavaValue result(T_VOID);
3597 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3598 vmSymbols::void_method_signature(), CHECK);
3599 }
3600
3601 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3602 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3603
3604 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3605 create_vm_init_libraries();
3606 }
3607
3608 initialize_class(vmSymbols::java_lang_String(), CHECK);
3609
3610 // Inject CompactStrings value after the static initializers for String ran.
3611 java_lang_String::set_compact_strings(CompactStrings);
3612
3613 // Initialize java_lang.System (needed before creating the thread)
3614 initialize_class(vmSymbols::java_lang_System(), CHECK);
3615 // The VM creates & returns objects of this class. Make sure it's initialized.
3616 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3617 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3618 Handle thread_group = create_initial_thread_group(CHECK);
3619 Universe::set_main_thread_group(thread_group());
3620 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3621 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3622 main_thread->set_threadObj(thread_object);
3623 // Set thread status to running since main thread has
3624 // been started and running.
3625 java_lang_Thread::set_thread_status(thread_object,
3626 java_lang_Thread::RUNNABLE);
3627
3628 // The VM creates objects of this class.
3629 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3630
3631 // The VM preresolves methods to these classes. Make sure that they get initialized
3632 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3633 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3634
3635 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3636 call_initPhase1(CHECK);
3637
3638 // get the Java runtime name after java.lang.System is initialized
3639 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3640 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3641
3642 // an instance of OutOfMemory exception has been allocated earlier
3643 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3644 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3645 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3646 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3647 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3648 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3649 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3650 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3651 }
3652
3653 void Threads::initialize_jsr292_core_classes(TRAPS) {
3654 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3655
3656 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3657 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3658 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3659 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3660 }
3661
3662 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3663 extern void JDK_Version_init();
3664
3665 // Preinitialize version info.
3666 VM_Version::early_initialize();
3667
3668 // Check version
3669 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3670
3671 // Initialize library-based TLS
3672 ThreadLocalStorage::init();
3673
3674 // Initialize the output stream module
3675 ostream_init();
3676
3677 // Process java launcher properties.
3678 Arguments::process_sun_java_launcher_properties(args);
3679
3680 // Initialize the os module
3681 os::init();
3682
3683 // Record VM creation timing statistics
3684 TraceVmCreationTime create_vm_timer;
3685 create_vm_timer.start();
3686
3687 // Initialize system properties.
3688 Arguments::init_system_properties();
3689
3690 // So that JDK version can be used as a discriminator when parsing arguments
3691 JDK_Version_init();
3692
3693 // Update/Initialize System properties after JDK version number is known
3694 Arguments::init_version_specific_system_properties();
3695
3696 // Make sure to initialize log configuration *before* parsing arguments
3697 LogConfiguration::initialize(create_vm_timer.begin_time());
3698
3699 // Parse arguments
3700 // Note: this internally calls os::init_container_support()
3701 jint parse_result = Arguments::parse(args);
3702 if (parse_result != JNI_OK) return parse_result;
3703
3704 os::init_before_ergo();
3705
3706 jint ergo_result = Arguments::apply_ergo();
3707 if (ergo_result != JNI_OK) return ergo_result;
3708
3709 // Final check of all ranges after ergonomics which may change values.
3710 if (!JVMFlagRangeList::check_ranges()) {
3711 return JNI_EINVAL;
3712 }
3713
3714 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3715 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo);
3716 if (!constraint_result) {
3717 return JNI_EINVAL;
3718 }
3719
3720 JVMFlagWriteableList::mark_startup();
3721
3722 if (PauseAtStartup) {
3723 os::pause();
3724 }
3725
3726 HOTSPOT_VM_INIT_BEGIN();
3727
3728 // Timing (must come after argument parsing)
3729 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3730
3731 // Initialize the os module after parsing the args
3732 jint os_init_2_result = os::init_2();
3733 if (os_init_2_result != JNI_OK) return os_init_2_result;
3734
3735 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3736 // Initialize assert poison page mechanism.
3737 if (ShowRegistersOnAssert) {
3738 initialize_assert_poison();
3739 }
3740 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3741
3742 SafepointMechanism::initialize();
3743
3744 jint adjust_after_os_result = Arguments::adjust_after_os();
3745 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3746
3747 // Initialize output stream logging
3748 ostream_init_log();
3749
3750 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3751 // Must be before create_vm_init_agents()
3752 if (Arguments::init_libraries_at_startup()) {
3753 convert_vm_init_libraries_to_agents();
3754 }
3755
3756 // Launch -agentlib/-agentpath and converted -Xrun agents
3757 if (Arguments::init_agents_at_startup()) {
3758 create_vm_init_agents();
3759 }
3760
3761 // Initialize Threads state
3762 _thread_list = NULL;
3763 _number_of_threads = 0;
3764 _number_of_non_daemon_threads = 0;
3765
3766 // Initialize global data structures and create system classes in heap
3767 vm_init_globals();
3768
3769 #if INCLUDE_JVMCI
3770 if (JVMCICounterSize > 0) {
3771 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3772 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3773 } else {
3774 JavaThread::_jvmci_old_thread_counters = NULL;
3775 }
3776 #endif // INCLUDE_JVMCI
3777
3778 // Attach the main thread to this os thread
3779 JavaThread* main_thread = new JavaThread();
3780 main_thread->set_thread_state(_thread_in_vm);
3781 main_thread->initialize_thread_current();
3782 // must do this before set_active_handles
3783 main_thread->record_stack_base_and_size();
3784 main_thread->register_thread_stack_with_NMT();
3785 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3786
3787 if (!main_thread->set_as_starting_thread()) {
3788 vm_shutdown_during_initialization(
3789 "Failed necessary internal allocation. Out of swap space");
3790 main_thread->smr_delete();
3791 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3792 return JNI_ENOMEM;
3793 }
3794
3795 // Enable guard page *after* os::create_main_thread(), otherwise it would
3796 // crash Linux VM, see notes in os_linux.cpp.
3797 main_thread->create_stack_guard_pages();
3798
3799 // Initialize Java-Level synchronization subsystem
3800 ObjectMonitor::Initialize();
3801
3802 // Initialize global modules
3803 jint status = init_globals();
3804 if (status != JNI_OK) {
3805 main_thread->smr_delete();
3806 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3807 return status;
3808 }
3809
3810 JFR_ONLY(Jfr::on_vm_init();)
3811
3812 // Should be done after the heap is fully created
3813 main_thread->cache_global_variables();
3814
3815 HandleMark hm;
3816
3817 { MutexLocker mu(Threads_lock);
3818 Threads::add(main_thread);
3819 }
3820
3821 // Any JVMTI raw monitors entered in onload will transition into
3822 // real raw monitor. VM is setup enough here for raw monitor enter.
3823 JvmtiExport::transition_pending_onload_raw_monitors();
3824
3825 // Create the VMThread
3826 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3827
3828 VMThread::create();
3829 Thread* vmthread = VMThread::vm_thread();
3830
3831 if (!os::create_thread(vmthread, os::vm_thread)) {
3832 vm_exit_during_initialization("Cannot create VM thread. "
3833 "Out of system resources.");
3834 }
3835
3836 // Wait for the VM thread to become ready, and VMThread::run to initialize
3837 // Monitors can have spurious returns, must always check another state flag
3838 {
3839 MutexLocker ml(Notify_lock);
3840 os::start_thread(vmthread);
3841 while (vmthread->active_handles() == NULL) {
3842 Notify_lock->wait();
3843 }
3844 }
3845 }
3846
3847 assert(Universe::is_fully_initialized(), "not initialized");
3848 if (VerifyDuringStartup) {
3849 // Make sure we're starting with a clean slate.
3850 VM_Verify verify_op;
3851 VMThread::execute(&verify_op);
3852 }
3853
3854 // We need this to update the java.vm.info property in case any flags used
3855 // to initially define it have been changed. This is needed for both CDS and
3856 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info
3857 // is initially computed. See Abstract_VM_Version::vm_info_string().
3858 // This update must happen before we initialize the java classes, but
3859 // after any initialization logic that might modify the flags.
3860 Arguments::update_vm_info_property(VM_Version::vm_info_string());
3861
3862 Thread* THREAD = Thread::current();
3863
3864 // Always call even when there are not JVMTI environments yet, since environments
3865 // may be attached late and JVMTI must track phases of VM execution
3866 JvmtiExport::enter_early_start_phase();
3867
3868 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3869 JvmtiExport::post_early_vm_start();
3870
3871 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3872
3873 quicken_jni_functions();
3874
3875 // No more stub generation allowed after that point.
3876 StubCodeDesc::freeze();
3877
3878 // Set flag that basic initialization has completed. Used by exceptions and various
3879 // debug stuff, that does not work until all basic classes have been initialized.
3880 set_init_completed();
3881
3882 LogConfiguration::post_initialize();
3883 Metaspace::post_initialize();
3884
3885 HOTSPOT_VM_INIT_END();
3886
3887 // record VM initialization completion time
3888 #if INCLUDE_MANAGEMENT
3889 Management::record_vm_init_completed();
3890 #endif // INCLUDE_MANAGEMENT
3891
3892 // Signal Dispatcher needs to be started before VMInit event is posted
3893 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3894
3895 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3896 if (!DisableAttachMechanism) {
3897 AttachListener::vm_start();
3898 if (StartAttachListener || AttachListener::init_at_startup()) {
3899 AttachListener::init();
3900 }
3901 }
3902
3903 // Launch -Xrun agents
3904 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3905 // back-end can launch with -Xdebug -Xrunjdwp.
3906 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3907 create_vm_init_libraries();
3908 }
3909
3910 if (CleanChunkPoolAsync) {
3911 Chunk::start_chunk_pool_cleaner_task();
3912 }
3913
3914 // initialize compiler(s)
3915 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3916 #if INCLUDE_JVMCI
3917 bool force_JVMCI_intialization = false;
3918 if (EnableJVMCI) {
3919 // Initialize JVMCI eagerly when it is explicitly requested.
3920 // Or when JVMCIPrintProperties is enabled.
3921 // The JVMCI Java initialization code will read this flag and
3922 // do the printing if it's set.
3923 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties;
3924
3925 if (!force_JVMCI_intialization) {
3926 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3927 // compilations via JVMCI will not actually block until JVMCI is initialized.
3928 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3929 }
3930 }
3931 #endif
3932 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
3933 // Postpone completion of compiler initialization to after JVMCI
3934 // is initialized to avoid timeouts of blocking compilations.
3935 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
3936 CompileBroker::compilation_init_phase2();
3937 }
3938 #endif
3939
3940 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3941 // It is done after compilers are initialized, because otherwise compilations of
3942 // signature polymorphic MH intrinsics can be missed
3943 // (see SystemDictionary::find_method_handle_intrinsic).
3944 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3945
3946 // This will initialize the module system. Only java.base classes can be
3947 // loaded until phase 2 completes
3948 call_initPhase2(CHECK_JNI_ERR);
3949
3950 // Always call even when there are not JVMTI environments yet, since environments
3951 // may be attached late and JVMTI must track phases of VM execution
3952 JvmtiExport::enter_start_phase();
3953
3954 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3955 JvmtiExport::post_vm_start();
3956
3957 // Final system initialization including security manager and system class loader
3958 call_initPhase3(CHECK_JNI_ERR);
3959
3960 // cache the system and platform class loaders
3961 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
3962
3963 #if INCLUDE_CDS
3964 if (DumpSharedSpaces) {
3965 // capture the module path info from the ModuleEntryTable
3966 ClassLoader::initialize_module_path(THREAD);
3967 }
3968 #endif
3969
3970 #if INCLUDE_JVMCI
3971 if (force_JVMCI_intialization) {
3972 JVMCIRuntime::force_initialization(CHECK_JNI_ERR);
3973 CompileBroker::compilation_init_phase2();
3974 }
3975 #endif
3976
3977 // Always call even when there are not JVMTI environments yet, since environments
3978 // may be attached late and JVMTI must track phases of VM execution
3979 JvmtiExport::enter_live_phase();
3980
3981 // Make perfmemory accessible
3982 PerfMemory::set_accessible(true);
3983
3984 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3985 JvmtiExport::post_vm_initialized();
3986
3987 JFR_ONLY(Jfr::on_vm_start();)
3988
3989 #if INCLUDE_MANAGEMENT
3990 Management::initialize(THREAD);
3991
3992 if (HAS_PENDING_EXCEPTION) {
3993 // management agent fails to start possibly due to
3994 // configuration problem and is responsible for printing
3995 // stack trace if appropriate. Simply exit VM.
3996 vm_exit(1);
3997 }
3998 #endif // INCLUDE_MANAGEMENT
3999
4000 if (MemProfiling) MemProfiler::engage();
4001 StatSampler::engage();
4002 if (CheckJNICalls) JniPeriodicChecker::engage();
4003
4004 BiasedLocking::init();
4005
4006 #if INCLUDE_RTM_OPT
4007 RTMLockingCounters::init();
4008 #endif
4009
4010 if (JDK_Version::current().post_vm_init_hook_enabled()) {
4011 call_postVMInitHook(THREAD);
4012 // The Java side of PostVMInitHook.run must deal with all
4013 // exceptions and provide means of diagnosis.
4014 if (HAS_PENDING_EXCEPTION) {
4015 CLEAR_PENDING_EXCEPTION;
4016 }
4017 }
4018
4019 {
4020 MutexLocker ml(PeriodicTask_lock);
4021 // Make sure the WatcherThread can be started by WatcherThread::start()
4022 // or by dynamic enrollment.
4023 WatcherThread::make_startable();
4024 // Start up the WatcherThread if there are any periodic tasks
4025 // NOTE: All PeriodicTasks should be registered by now. If they
4026 // aren't, late joiners might appear to start slowly (we might
4027 // take a while to process their first tick).
4028 if (PeriodicTask::num_tasks() > 0) {
4029 WatcherThread::start();
4030 }
4031 }
4032
4033 create_vm_timer.end();
4034 #ifdef ASSERT
4035 _vm_complete = true;
4036 #endif
4037
4038 if (DumpSharedSpaces) {
4039 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
4040 ShouldNotReachHere();
4041 }
4042
4043 return JNI_OK;
4044 }
4045
4046 // type for the Agent_OnLoad and JVM_OnLoad entry points
4047 extern "C" {
4048 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
4049 }
4050 // Find a command line agent library and return its entry point for
4051 // -agentlib: -agentpath: -Xrun
4052 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
4053 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
4054 const char *on_load_symbols[],
4055 size_t num_symbol_entries) {
4056 OnLoadEntry_t on_load_entry = NULL;
4057 void *library = NULL;
4058
4059 if (!agent->valid()) {
4060 char buffer[JVM_MAXPATHLEN];
4061 char ebuf[1024] = "";
4062 const char *name = agent->name();
4063 const char *msg = "Could not find agent library ";
4064
4065 // First check to see if agent is statically linked into executable
4066 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
4067 library = agent->os_lib();
4068 } else if (agent->is_absolute_path()) {
4069 library = os::dll_load(name, ebuf, sizeof ebuf);
4070 if (library == NULL) {
4071 const char *sub_msg = " in absolute path, with error: ";
4072 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4073 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4074 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4075 // If we can't find the agent, exit.
4076 vm_exit_during_initialization(buf, NULL);
4077 FREE_C_HEAP_ARRAY(char, buf);
4078 }
4079 } else {
4080 // Try to load the agent from the standard dll directory
4081 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4082 name)) {
4083 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4084 }
4085 if (library == NULL) { // Try the library path directory.
4086 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4087 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4088 }
4089 if (library == NULL) {
4090 const char *sub_msg = " on the library path, with error: ";
4091 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4092
4093 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4094 strlen(ebuf) + strlen(sub_msg2) + 1;
4095 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4096 if (!agent->is_instrument_lib()) {
4097 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4098 } else {
4099 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4100 }
4101 // If we can't find the agent, exit.
4102 vm_exit_during_initialization(buf, NULL);
4103 FREE_C_HEAP_ARRAY(char, buf);
4104 }
4105 }
4106 }
4107 agent->set_os_lib(library);
4108 agent->set_valid();
4109 }
4110
4111 // Find the OnLoad function.
4112 on_load_entry =
4113 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4114 false,
4115 on_load_symbols,
4116 num_symbol_entries));
4117 return on_load_entry;
4118 }
4119
4120 // Find the JVM_OnLoad entry point
4121 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4122 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4123 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4124 }
4125
4126 // Find the Agent_OnLoad entry point
4127 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4128 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4129 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4130 }
4131
4132 // For backwards compatibility with -Xrun
4133 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4134 // treated like -agentpath:
4135 // Must be called before agent libraries are created
4136 void Threads::convert_vm_init_libraries_to_agents() {
4137 AgentLibrary* agent;
4138 AgentLibrary* next;
4139
4140 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4141 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4142 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4143
4144 // If there is an JVM_OnLoad function it will get called later,
4145 // otherwise see if there is an Agent_OnLoad
4146 if (on_load_entry == NULL) {
4147 on_load_entry = lookup_agent_on_load(agent);
4148 if (on_load_entry != NULL) {
4149 // switch it to the agent list -- so that Agent_OnLoad will be called,
4150 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4151 Arguments::convert_library_to_agent(agent);
4152 } else {
4153 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4154 }
4155 }
4156 }
4157 }
4158
4159 // Create agents for -agentlib: -agentpath: and converted -Xrun
4160 // Invokes Agent_OnLoad
4161 // Called very early -- before JavaThreads exist
4162 void Threads::create_vm_init_agents() {
4163 extern struct JavaVM_ main_vm;
4164 AgentLibrary* agent;
4165
4166 JvmtiExport::enter_onload_phase();
4167
4168 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4169 // CDS dumping does not support native JVMTI agent.
4170 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
4171 if (DumpSharedSpaces) {
4172 if(!agent->is_instrument_lib()) {
4173 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
4174 } else if (!AllowArchivingWithJavaAgent) {
4175 vm_exit_during_cds_dumping(
4176 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
4177 }
4178 }
4179
4180 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4181
4182 if (on_load_entry != NULL) {
4183 // Invoke the Agent_OnLoad function
4184 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4185 if (err != JNI_OK) {
4186 vm_exit_during_initialization("agent library failed to init", agent->name());
4187 }
4188 } else {
4189 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4190 }
4191 }
4192
4193 JvmtiExport::enter_primordial_phase();
4194 }
4195
4196 extern "C" {
4197 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4198 }
4199
4200 void Threads::shutdown_vm_agents() {
4201 // Send any Agent_OnUnload notifications
4202 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4203 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4204 extern struct JavaVM_ main_vm;
4205 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4206
4207 // Find the Agent_OnUnload function.
4208 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4209 os::find_agent_function(agent,
4210 false,
4211 on_unload_symbols,
4212 num_symbol_entries));
4213
4214 // Invoke the Agent_OnUnload function
4215 if (unload_entry != NULL) {
4216 JavaThread* thread = JavaThread::current();
4217 ThreadToNativeFromVM ttn(thread);
4218 HandleMark hm(thread);
4219 (*unload_entry)(&main_vm);
4220 }
4221 }
4222 }
4223
4224 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4225 // Invokes JVM_OnLoad
4226 void Threads::create_vm_init_libraries() {
4227 extern struct JavaVM_ main_vm;
4228 AgentLibrary* agent;
4229
4230 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4231 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4232
4233 if (on_load_entry != NULL) {
4234 // Invoke the JVM_OnLoad function
4235 JavaThread* thread = JavaThread::current();
4236 ThreadToNativeFromVM ttn(thread);
4237 HandleMark hm(thread);
4238 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4239 if (err != JNI_OK) {
4240 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4241 }
4242 } else {
4243 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4244 }
4245 }
4246 }
4247
4248
4249 // Last thread running calls java.lang.Shutdown.shutdown()
4250 void JavaThread::invoke_shutdown_hooks() {
4251 HandleMark hm(this);
4252
4253 // We could get here with a pending exception, if so clear it now.
4254 if (this->has_pending_exception()) {
4255 this->clear_pending_exception();
4256 }
4257
4258 EXCEPTION_MARK;
4259 Klass* shutdown_klass =
4260 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4261 THREAD);
4262 if (shutdown_klass != NULL) {
4263 // SystemDictionary::resolve_or_null will return null if there was
4264 // an exception. If we cannot load the Shutdown class, just don't
4265 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4266 // won't be run. Note that if a shutdown hook was registered,
4267 // the Shutdown class would have already been loaded
4268 // (Runtime.addShutdownHook will load it).
4269 JavaValue result(T_VOID);
4270 JavaCalls::call_static(&result,
4271 shutdown_klass,
4272 vmSymbols::shutdown_method_name(),
4273 vmSymbols::void_method_signature(),
4274 THREAD);
4275 }
4276 CLEAR_PENDING_EXCEPTION;
4277 }
4278
4279 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4280 // the program falls off the end of main(). Another VM exit path is through
4281 // vm_exit() when the program calls System.exit() to return a value or when
4282 // there is a serious error in VM. The two shutdown paths are not exactly
4283 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4284 // and VM_Exit op at VM level.
4285 //
4286 // Shutdown sequence:
4287 // + Shutdown native memory tracking if it is on
4288 // + Wait until we are the last non-daemon thread to execute
4289 // <-- every thing is still working at this moment -->
4290 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4291 // shutdown hooks
4292 // + Call before_exit(), prepare for VM exit
4293 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4294 // currently the only user of this mechanism is File.deleteOnExit())
4295 // > stop StatSampler, watcher thread, CMS threads,
4296 // post thread end and vm death events to JVMTI,
4297 // stop signal thread
4298 // + Call JavaThread::exit(), it will:
4299 // > release JNI handle blocks, remove stack guard pages
4300 // > remove this thread from Threads list
4301 // <-- no more Java code from this thread after this point -->
4302 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4303 // the compiler threads at safepoint
4304 // <-- do not use anything that could get blocked by Safepoint -->
4305 // + Disable tracing at JNI/JVM barriers
4306 // + Set _vm_exited flag for threads that are still running native code
4307 // + Call exit_globals()
4308 // > deletes tty
4309 // > deletes PerfMemory resources
4310 // + Delete this thread
4311 // + Return to caller
4312
4313 bool Threads::destroy_vm() {
4314 JavaThread* thread = JavaThread::current();
4315
4316 #ifdef ASSERT
4317 _vm_complete = false;
4318 #endif
4319 // Wait until we are the last non-daemon thread to execute
4320 { MutexLocker nu(Threads_lock);
4321 while (Threads::number_of_non_daemon_threads() > 1)
4322 // This wait should make safepoint checks, wait without a timeout,
4323 // and wait as a suspend-equivalent condition.
4324 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4325 Mutex::_as_suspend_equivalent_flag);
4326 }
4327
4328 EventShutdown e;
4329 if (e.should_commit()) {
4330 e.set_reason("No remaining non-daemon Java threads");
4331 e.commit();
4332 }
4333
4334 // Hang forever on exit if we are reporting an error.
4335 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4336 os::infinite_sleep();
4337 }
4338 os::wait_for_keypress_at_exit();
4339
4340 // run Java level shutdown hooks
4341 thread->invoke_shutdown_hooks();
4342
4343 before_exit(thread);
4344
4345 thread->exit(true);
4346
4347 // Stop VM thread.
4348 {
4349 // 4945125 The vm thread comes to a safepoint during exit.
4350 // GC vm_operations can get caught at the safepoint, and the
4351 // heap is unparseable if they are caught. Grab the Heap_lock
4352 // to prevent this. The GC vm_operations will not be able to
4353 // queue until after the vm thread is dead. After this point,
4354 // we'll never emerge out of the safepoint before the VM exits.
4355
4356 MutexLockerEx ml(Heap_lock, Mutex::_no_safepoint_check_flag);
4357
4358 VMThread::wait_for_vm_thread_exit();
4359 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4360 VMThread::destroy();
4361 }
4362
4363 // Now, all Java threads are gone except daemon threads. Daemon threads
4364 // running Java code or in VM are stopped by the Safepoint. However,
4365 // daemon threads executing native code are still running. But they
4366 // will be stopped at native=>Java/VM barriers. Note that we can't
4367 // simply kill or suspend them, as it is inherently deadlock-prone.
4368
4369 VM_Exit::set_vm_exited();
4370
4371 // Clean up ideal graph printers after the VMThread has started
4372 // the final safepoint which will block all the Compiler threads.
4373 // Note that this Thread has already logically exited so the
4374 // clean_up() function's use of a JavaThreadIteratorWithHandle
4375 // would be a problem except set_vm_exited() has remembered the
4376 // shutdown thread which is granted a policy exception.
4377 #if defined(COMPILER2) && !defined(PRODUCT)
4378 IdealGraphPrinter::clean_up();
4379 #endif
4380
4381 notify_vm_shutdown();
4382
4383 // exit_globals() will delete tty
4384 exit_globals();
4385
4386 // We are after VM_Exit::set_vm_exited() so we can't call
4387 // thread->smr_delete() or we will block on the Threads_lock.
4388 // Deleting the shutdown thread here is safe because another
4389 // JavaThread cannot have an active ThreadsListHandle for
4390 // this JavaThread.
4391 delete thread;
4392
4393 #if INCLUDE_JVMCI
4394 if (JVMCICounterSize > 0) {
4395 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4396 }
4397 #endif
4398
4399 LogConfiguration::finalize();
4400
4401 return true;
4402 }
4403
4404
4405 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4406 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4407 return is_supported_jni_version(version);
4408 }
4409
4410
4411 jboolean Threads::is_supported_jni_version(jint version) {
4412 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4413 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4414 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4415 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4416 if (version == JNI_VERSION_9) return JNI_TRUE;
4417 if (version == JNI_VERSION_10) return JNI_TRUE;
4418 return JNI_FALSE;
4419 }
4420
4421
4422 void Threads::add(JavaThread* p, bool force_daemon) {
4423 // The threads lock must be owned at this point
4424 assert(Threads_lock->owned_by_self(), "must have threads lock");
4425
4426 BarrierSet::barrier_set()->on_thread_attach(p);
4427
4428 p->set_next(_thread_list);
4429 _thread_list = p;
4430
4431 // Once a JavaThread is added to the Threads list, smr_delete() has
4432 // to be used to delete it. Otherwise we can just delete it directly.
4433 p->set_on_thread_list();
4434
4435 _number_of_threads++;
4436 oop threadObj = p->threadObj();
4437 bool daemon = true;
4438 // Bootstrapping problem: threadObj can be null for initial
4439 // JavaThread (or for threads attached via JNI)
4440 if ((!force_daemon) && !is_daemon((threadObj))) {
4441 _number_of_non_daemon_threads++;
4442 daemon = false;
4443 }
4444
4445 ThreadService::add_thread(p, daemon);
4446
4447 // Maintain fast thread list
4448 ThreadsSMRSupport::add_thread(p);
4449
4450 // Possible GC point.
4451 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4452 }
4453
4454 void Threads::remove(JavaThread* p) {
4455
4456 // Reclaim the objectmonitors from the omInUseList and omFreeList of the moribund thread.
4457 ObjectSynchronizer::omFlush(p);
4458
4459 // Extra scope needed for Thread_lock, so we can check
4460 // that we do not remove thread without safepoint code notice
4461 { MutexLocker ml(Threads_lock);
4462
4463 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4464
4465 // Maintain fast thread list
4466 ThreadsSMRSupport::remove_thread(p);
4467
4468 JavaThread* current = _thread_list;
4469 JavaThread* prev = NULL;
4470
4471 while (current != p) {
4472 prev = current;
4473 current = current->next();
4474 }
4475
4476 if (prev) {
4477 prev->set_next(current->next());
4478 } else {
4479 _thread_list = p->next();
4480 }
4481
4482 _number_of_threads--;
4483 oop threadObj = p->threadObj();
4484 bool daemon = true;
4485 if (!is_daemon(threadObj)) {
4486 _number_of_non_daemon_threads--;
4487 daemon = false;
4488
4489 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4490 // on destroy_vm will wake up.
4491 if (number_of_non_daemon_threads() == 1) {
4492 Threads_lock->notify_all();
4493 }
4494 }
4495 ThreadService::remove_thread(p, daemon);
4496
4497 // Make sure that safepoint code disregard this thread. This is needed since
4498 // the thread might mess around with locks after this point. This can cause it
4499 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4500 // of this thread since it is removed from the queue.
4501 p->set_terminated_value();
4502 } // unlock Threads_lock
4503
4504 // Since Events::log uses a lock, we grab it outside the Threads_lock
4505 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4506 }
4507
4508 // Operations on the Threads list for GC. These are not explicitly locked,
4509 // but the garbage collector must provide a safe context for them to run.
4510 // In particular, these things should never be called when the Threads_lock
4511 // is held by some other thread. (Note: the Safepoint abstraction also
4512 // uses the Threads_lock to guarantee this property. It also makes sure that
4513 // all threads gets blocked when exiting or starting).
4514
4515 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4516 ALL_JAVA_THREADS(p) {
4517 p->oops_do(f, cf);
4518 }
4519 VMThread::vm_thread()->oops_do(f, cf);
4520 }
4521
4522 void Threads::change_thread_claim_parity() {
4523 // Set the new claim parity.
4524 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4525 "Not in range.");
4526 _thread_claim_parity++;
4527 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4528 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4529 "Not in range.");
4530 }
4531
4532 #ifdef ASSERT
4533 void Threads::assert_all_threads_claimed() {
4534 ALL_JAVA_THREADS(p) {
4535 const int thread_parity = p->oops_do_parity();
4536 assert((thread_parity == _thread_claim_parity),
4537 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4538 }
4539 VMThread* vmt = VMThread::vm_thread();
4540 const int thread_parity = vmt->oops_do_parity();
4541 assert((thread_parity == _thread_claim_parity),
4542 "VMThread " PTR_FORMAT " has incorrect parity %d != %d", p2i(vmt), thread_parity, _thread_claim_parity);
4543 }
4544 #endif // ASSERT
4545
4546 class ParallelOopsDoThreadClosure : public ThreadClosure {
4547 private:
4548 OopClosure* _f;
4549 CodeBlobClosure* _cf;
4550 public:
4551 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4552 void do_thread(Thread* t) {
4553 t->oops_do(_f, _cf);
4554 }
4555 };
4556
4557 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4558 ParallelOopsDoThreadClosure tc(f, cf);
4559 possibly_parallel_threads_do(is_par, &tc);
4560 }
4561
4562 void Threads::nmethods_do(CodeBlobClosure* cf) {
4563 ALL_JAVA_THREADS(p) {
4564 // This is used by the code cache sweeper to mark nmethods that are active
4565 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4566 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4567 if(!p->is_Code_cache_sweeper_thread()) {
4568 p->nmethods_do(cf);
4569 }
4570 }
4571 }
4572
4573 void Threads::metadata_do(void f(Metadata*)) {
4574 ALL_JAVA_THREADS(p) {
4575 p->metadata_do(f);
4576 }
4577 }
4578
4579 class ThreadHandlesClosure : public ThreadClosure {
4580 void (*_f)(Metadata*);
4581 public:
4582 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4583 virtual void do_thread(Thread* thread) {
4584 thread->metadata_handles_do(_f);
4585 }
4586 };
4587
4588 void Threads::metadata_handles_do(void f(Metadata*)) {
4589 // Only walk the Handles in Thread.
4590 ThreadHandlesClosure handles_closure(f);
4591 threads_do(&handles_closure);
4592 }
4593
4594 void Threads::deoptimized_wrt_marked_nmethods() {
4595 ALL_JAVA_THREADS(p) {
4596 p->deoptimized_wrt_marked_nmethods();
4597 }
4598 }
4599
4600
4601 // Get count Java threads that are waiting to enter the specified monitor.
4602 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4603 int count,
4604 address monitor) {
4605 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4606
4607 int i = 0;
4608 DO_JAVA_THREADS(t_list, p) {
4609 if (!p->can_call_java()) continue;
4610
4611 address pending = (address)p->current_pending_monitor();
4612 if (pending == monitor) { // found a match
4613 if (i < count) result->append(p); // save the first count matches
4614 i++;
4615 }
4616 }
4617
4618 return result;
4619 }
4620
4621
4622 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4623 address owner) {
4624 // NULL owner means not locked so we can skip the search
4625 if (owner == NULL) return NULL;
4626
4627 DO_JAVA_THREADS(t_list, p) {
4628 // first, see if owner is the address of a Java thread
4629 if (owner == (address)p) return p;
4630 }
4631
4632 // Cannot assert on lack of success here since this function may be
4633 // used by code that is trying to report useful problem information
4634 // like deadlock detection.
4635 if (UseHeavyMonitors) return NULL;
4636
4637 // If we didn't find a matching Java thread and we didn't force use of
4638 // heavyweight monitors, then the owner is the stack address of the
4639 // Lock Word in the owning Java thread's stack.
4640 //
4641 JavaThread* the_owner = NULL;
4642 DO_JAVA_THREADS(t_list, q) {
4643 if (q->is_lock_owned(owner)) {
4644 the_owner = q;
4645 break;
4646 }
4647 }
4648
4649 // cannot assert on lack of success here; see above comment
4650 return the_owner;
4651 }
4652
4653 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4654 void Threads::print_on(outputStream* st, bool print_stacks,
4655 bool internal_format, bool print_concurrent_locks,
4656 bool print_extended_info) {
4657 char buf[32];
4658 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4659
4660 st->print_cr("Full thread dump %s (%s %s):",
4661 VM_Version::vm_name(),
4662 VM_Version::vm_release(),
4663 VM_Version::vm_info_string());
4664 st->cr();
4665
4666 #if INCLUDE_SERVICES
4667 // Dump concurrent locks
4668 ConcurrentLocksDump concurrent_locks;
4669 if (print_concurrent_locks) {
4670 concurrent_locks.dump_at_safepoint();
4671 }
4672 #endif // INCLUDE_SERVICES
4673
4674 ThreadsSMRSupport::print_info_on(st);
4675 st->cr();
4676
4677 ALL_JAVA_THREADS(p) {
4678 ResourceMark rm;
4679 p->print_on(st, print_extended_info);
4680 if (print_stacks) {
4681 if (internal_format) {
4682 p->trace_stack();
4683 } else {
4684 p->print_stack_on(st);
4685 }
4686 }
4687 st->cr();
4688 #if INCLUDE_SERVICES
4689 if (print_concurrent_locks) {
4690 concurrent_locks.print_locks_on(p, st);
4691 }
4692 #endif // INCLUDE_SERVICES
4693 }
4694
4695 VMThread::vm_thread()->print_on(st);
4696 st->cr();
4697 Universe::heap()->print_gc_threads_on(st);
4698 WatcherThread* wt = WatcherThread::watcher_thread();
4699 if (wt != NULL) {
4700 wt->print_on(st);
4701 st->cr();
4702 }
4703
4704 st->flush();
4705 }
4706
4707 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4708 int buflen, bool* found_current) {
4709 if (this_thread != NULL) {
4710 bool is_current = (current == this_thread);
4711 *found_current = *found_current || is_current;
4712 st->print("%s", is_current ? "=>" : " ");
4713
4714 st->print(PTR_FORMAT, p2i(this_thread));
4715 st->print(" ");
4716 this_thread->print_on_error(st, buf, buflen);
4717 st->cr();
4718 }
4719 }
4720
4721 class PrintOnErrorClosure : public ThreadClosure {
4722 outputStream* _st;
4723 Thread* _current;
4724 char* _buf;
4725 int _buflen;
4726 bool* _found_current;
4727 public:
4728 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4729 int buflen, bool* found_current) :
4730 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4731
4732 virtual void do_thread(Thread* thread) {
4733 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4734 }
4735 };
4736
4737 // Threads::print_on_error() is called by fatal error handler. It's possible
4738 // that VM is not at safepoint and/or current thread is inside signal handler.
4739 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4740 // memory (even in resource area), it might deadlock the error handler.
4741 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4742 int buflen) {
4743 ThreadsSMRSupport::print_info_on(st);
4744 st->cr();
4745
4746 bool found_current = false;
4747 st->print_cr("Java Threads: ( => current thread )");
4748 ALL_JAVA_THREADS(thread) {
4749 print_on_error(thread, st, current, buf, buflen, &found_current);
4750 }
4751 st->cr();
4752
4753 st->print_cr("Other Threads:");
4754 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4755 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4756
4757 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4758 Universe::heap()->gc_threads_do(&print_closure);
4759
4760 if (!found_current) {
4761 st->cr();
4762 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4763 current->print_on_error(st, buf, buflen);
4764 st->cr();
4765 }
4766 st->cr();
4767
4768 st->print_cr("Threads with active compile tasks:");
4769 print_threads_compiling(st, buf, buflen);
4770 }
4771
4772 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) {
4773 ALL_JAVA_THREADS(thread) {
4774 if (thread->is_Compiler_thread()) {
4775 CompilerThread* ct = (CompilerThread*) thread;
4776
4777 // Keep task in local variable for NULL check.
4778 // ct->_task might be set to NULL by concurring compiler thread
4779 // because it completed the compilation. The task is never freed,
4780 // though, just returned to a free list.
4781 CompileTask* task = ct->task();
4782 if (task != NULL) {
4783 thread->print_name_on_error(st, buf, buflen);
4784 st->print(" ");
4785 task->print(st, NULL, true, true);
4786 }
4787 }
4788 }
4789 }
4790
4791
4792 // Internal SpinLock and Mutex
4793 // Based on ParkEvent
4794
4795 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4796 //
4797 // We employ SpinLocks _only for low-contention, fixed-length
4798 // short-duration critical sections where we're concerned
4799 // about native mutex_t or HotSpot Mutex:: latency.
4800 // The mux construct provides a spin-then-block mutual exclusion
4801 // mechanism.
4802 //
4803 // Testing has shown that contention on the ListLock guarding gFreeList
4804 // is common. If we implement ListLock as a simple SpinLock it's common
4805 // for the JVM to devolve to yielding with little progress. This is true
4806 // despite the fact that the critical sections protected by ListLock are
4807 // extremely short.
4808 //
4809 // TODO-FIXME: ListLock should be of type SpinLock.
4810 // We should make this a 1st-class type, integrated into the lock
4811 // hierarchy as leaf-locks. Critically, the SpinLock structure
4812 // should have sufficient padding to avoid false-sharing and excessive
4813 // cache-coherency traffic.
4814
4815
4816 typedef volatile int SpinLockT;
4817
4818 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4819 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4820 return; // normal fast-path return
4821 }
4822
4823 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4824 int ctr = 0;
4825 int Yields = 0;
4826 for (;;) {
4827 while (*adr != 0) {
4828 ++ctr;
4829 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4830 if (Yields > 5) {
4831 os::naked_short_sleep(1);
4832 } else {
4833 os::naked_yield();
4834 ++Yields;
4835 }
4836 } else {
4837 SpinPause();
4838 }
4839 }
4840 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4841 }
4842 }
4843
4844 void Thread::SpinRelease(volatile int * adr) {
4845 assert(*adr != 0, "invariant");
4846 OrderAccess::fence(); // guarantee at least release consistency.
4847 // Roach-motel semantics.
4848 // It's safe if subsequent LDs and STs float "up" into the critical section,
4849 // but prior LDs and STs within the critical section can't be allowed
4850 // to reorder or float past the ST that releases the lock.
4851 // Loads and stores in the critical section - which appear in program
4852 // order before the store that releases the lock - must also appear
4853 // before the store that releases the lock in memory visibility order.
4854 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4855 // the ST of 0 into the lock-word which releases the lock, so fence
4856 // more than covers this on all platforms.
4857 *adr = 0;
4858 }
4859
4860 // muxAcquire and muxRelease:
4861 //
4862 // * muxAcquire and muxRelease support a single-word lock-word construct.
4863 // The LSB of the word is set IFF the lock is held.
4864 // The remainder of the word points to the head of a singly-linked list
4865 // of threads blocked on the lock.
4866 //
4867 // * The current implementation of muxAcquire-muxRelease uses its own
4868 // dedicated Thread._MuxEvent instance. If we're interested in
4869 // minimizing the peak number of extant ParkEvent instances then
4870 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4871 // as certain invariants were satisfied. Specifically, care would need
4872 // to be taken with regards to consuming unpark() "permits".
4873 // A safe rule of thumb is that a thread would never call muxAcquire()
4874 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4875 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4876 // consume an unpark() permit intended for monitorenter, for instance.
4877 // One way around this would be to widen the restricted-range semaphore
4878 // implemented in park(). Another alternative would be to provide
4879 // multiple instances of the PlatformEvent() for each thread. One
4880 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4881 //
4882 // * Usage:
4883 // -- Only as leaf locks
4884 // -- for short-term locking only as muxAcquire does not perform
4885 // thread state transitions.
4886 //
4887 // Alternatives:
4888 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4889 // but with parking or spin-then-park instead of pure spinning.
4890 // * Use Taura-Oyama-Yonenzawa locks.
4891 // * It's possible to construct a 1-0 lock if we encode the lockword as
4892 // (List,LockByte). Acquire will CAS the full lockword while Release
4893 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4894 // acquiring threads use timers (ParkTimed) to detect and recover from
4895 // the stranding window. Thread/Node structures must be aligned on 256-byte
4896 // boundaries by using placement-new.
4897 // * Augment MCS with advisory back-link fields maintained with CAS().
4898 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4899 // The validity of the backlinks must be ratified before we trust the value.
4900 // If the backlinks are invalid the exiting thread must back-track through the
4901 // the forward links, which are always trustworthy.
4902 // * Add a successor indication. The LockWord is currently encoded as
4903 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4904 // to provide the usual futile-wakeup optimization.
4905 // See RTStt for details.
4906 //
4907
4908
4909 const intptr_t LOCKBIT = 1;
4910
4911 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4912 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4913 if (w == 0) return;
4914 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4915 return;
4916 }
4917
4918 ParkEvent * const Self = Thread::current()->_MuxEvent;
4919 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4920 for (;;) {
4921 int its = (os::is_MP() ? 100 : 0) + 1;
4922
4923 // Optional spin phase: spin-then-park strategy
4924 while (--its >= 0) {
4925 w = *Lock;
4926 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4927 return;
4928 }
4929 }
4930
4931 Self->reset();
4932 Self->OnList = intptr_t(Lock);
4933 // The following fence() isn't _strictly necessary as the subsequent
4934 // CAS() both serializes execution and ratifies the fetched *Lock value.
4935 OrderAccess::fence();
4936 for (;;) {
4937 w = *Lock;
4938 if ((w & LOCKBIT) == 0) {
4939 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4940 Self->OnList = 0; // hygiene - allows stronger asserts
4941 return;
4942 }
4943 continue; // Interference -- *Lock changed -- Just retry
4944 }
4945 assert(w & LOCKBIT, "invariant");
4946 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4947 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4948 }
4949
4950 while (Self->OnList != 0) {
4951 Self->park();
4952 }
4953 }
4954 }
4955
4956 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4957 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4958 if (w == 0) return;
4959 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4960 return;
4961 }
4962
4963 ParkEvent * ReleaseAfter = NULL;
4964 if (ev == NULL) {
4965 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4966 }
4967 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4968 for (;;) {
4969 guarantee(ev->OnList == 0, "invariant");
4970 int its = (os::is_MP() ? 100 : 0) + 1;
4971
4972 // Optional spin phase: spin-then-park strategy
4973 while (--its >= 0) {
4974 w = *Lock;
4975 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4976 if (ReleaseAfter != NULL) {
4977 ParkEvent::Release(ReleaseAfter);
4978 }
4979 return;
4980 }
4981 }
4982
4983 ev->reset();
4984 ev->OnList = intptr_t(Lock);
4985 // The following fence() isn't _strictly necessary as the subsequent
4986 // CAS() both serializes execution and ratifies the fetched *Lock value.
4987 OrderAccess::fence();
4988 for (;;) {
4989 w = *Lock;
4990 if ((w & LOCKBIT) == 0) {
4991 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4992 ev->OnList = 0;
4993 // We call ::Release while holding the outer lock, thus
4994 // artificially lengthening the critical section.
4995 // Consider deferring the ::Release() until the subsequent unlock(),
4996 // after we've dropped the outer lock.
4997 if (ReleaseAfter != NULL) {
4998 ParkEvent::Release(ReleaseAfter);
4999 }
5000 return;
5001 }
5002 continue; // Interference -- *Lock changed -- Just retry
5003 }
5004 assert(w & LOCKBIT, "invariant");
5005 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
5006 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
5007 }
5008
5009 while (ev->OnList != 0) {
5010 ev->park();
5011 }
5012 }
5013 }
5014
5015 // Release() must extract a successor from the list and then wake that thread.
5016 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
5017 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
5018 // Release() would :
5019 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
5020 // (B) Extract a successor from the private list "in-hand"
5021 // (C) attempt to CAS() the residual back into *Lock over null.
5022 // If there were any newly arrived threads and the CAS() would fail.
5023 // In that case Release() would detach the RATs, re-merge the list in-hand
5024 // with the RATs and repeat as needed. Alternately, Release() might
5025 // detach and extract a successor, but then pass the residual list to the wakee.
5026 // The wakee would be responsible for reattaching and remerging before it
5027 // competed for the lock.
5028 //
5029 // Both "pop" and DMR are immune from ABA corruption -- there can be
5030 // multiple concurrent pushers, but only one popper or detacher.
5031 // This implementation pops from the head of the list. This is unfair,
5032 // but tends to provide excellent throughput as hot threads remain hot.
5033 // (We wake recently run threads first).
5034 //
5035 // All paths through muxRelease() will execute a CAS.
5036 // Release consistency -- We depend on the CAS in muxRelease() to provide full
5037 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
5038 // executed within the critical section are complete and globally visible before the
5039 // store (CAS) to the lock-word that releases the lock becomes globally visible.
5040 void Thread::muxRelease(volatile intptr_t * Lock) {
5041 for (;;) {
5042 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
5043 assert(w & LOCKBIT, "invariant");
5044 if (w == LOCKBIT) return;
5045 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
5046 assert(List != NULL, "invariant");
5047 assert(List->OnList == intptr_t(Lock), "invariant");
5048 ParkEvent * const nxt = List->ListNext;
5049 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5050
5051 // The following CAS() releases the lock and pops the head element.
5052 // The CAS() also ratifies the previously fetched lock-word value.
5053 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
5054 continue;
5055 }
5056 List->OnList = 0;
5057 OrderAccess::fence();
5058 List->unpark();
5059 return;
5060 }
5061 }
5062
5063
5064 void Threads::verify() {
5065 ALL_JAVA_THREADS(p) {
5066 p->verify();
5067 }
5068 VMThread* thread = VMThread::vm_thread();
5069 if (thread != NULL) thread->verify();
5070 }