1 /*
2 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classLoader.hpp"
29 #include "classfile/javaClasses.hpp"
30 #include "classfile/moduleEntry.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "code/codeCache.hpp"
34 #include "code/scopeDesc.hpp"
35 #include "compiler/compileBroker.hpp"
36 #include "compiler/compileTask.hpp"
37 #include "gc/shared/barrierSet.hpp"
38 #include "gc/shared/gcId.hpp"
39 #include "gc/shared/gcLocker.inline.hpp"
40 #include "gc/shared/workgroup.hpp"
41 #include "interpreter/interpreter.hpp"
42 #include "interpreter/linkResolver.hpp"
43 #include "interpreter/oopMapCache.hpp"
44 #include "jfr/jfrEvents.hpp"
45 #include "jvmtifiles/jvmtiEnv.hpp"
46 #include "logging/log.hpp"
47 #include "logging/logConfiguration.hpp"
48 #include "logging/logStream.hpp"
49 #include "memory/allocation.inline.hpp"
50 #include "memory/metaspaceShared.hpp"
51 #include "memory/oopFactory.hpp"
52 #include "memory/resourceArea.hpp"
53 #include "memory/universe.hpp"
54 #include "oops/access.inline.hpp"
55 #include "oops/instanceKlass.hpp"
56 #include "oops/objArrayOop.hpp"
57 #include "oops/oop.inline.hpp"
58 #include "oops/symbol.hpp"
59 #include "oops/typeArrayOop.inline.hpp"
60 #include "oops/verifyOopClosure.hpp"
61 #include "prims/jvm_misc.hpp"
62 #include "prims/jvmtiExport.hpp"
63 #include "prims/jvmtiThreadState.hpp"
64 #include "runtime/arguments.hpp"
65 #include "runtime/atomic.hpp"
66 #include "runtime/biasedLocking.hpp"
67 #include "runtime/fieldDescriptor.inline.hpp"
68 #include "runtime/flags/jvmFlagConstraintList.hpp"
69 #include "runtime/flags/jvmFlagRangeList.hpp"
70 #include "runtime/flags/jvmFlagWriteableList.hpp"
71 #include "runtime/deoptimization.hpp"
72 #include "runtime/frame.inline.hpp"
73 #include "runtime/handles.inline.hpp"
74 #include "runtime/handshake.hpp"
75 #include "runtime/init.hpp"
76 #include "runtime/interfaceSupport.inline.hpp"
77 #include "runtime/java.hpp"
78 #include "runtime/javaCalls.hpp"
79 #include "runtime/jniHandles.inline.hpp"
80 #include "runtime/jniPeriodicChecker.hpp"
81 #include "runtime/memprofiler.hpp"
82 #include "runtime/mutexLocker.hpp"
83 #include "runtime/objectMonitor.hpp"
84 #include "runtime/orderAccess.hpp"
85 #include "runtime/osThread.hpp"
86 #include "runtime/prefetch.inline.hpp"
87 #include "runtime/safepoint.hpp"
88 #include "runtime/safepointMechanism.inline.hpp"
89 #include "runtime/safepointVerifiers.hpp"
90 #include "runtime/sharedRuntime.hpp"
91 #include "runtime/statSampler.hpp"
92 #include "runtime/stubRoutines.hpp"
93 #include "runtime/sweeper.hpp"
94 #include "runtime/task.hpp"
95 #include "runtime/thread.inline.hpp"
96 #include "runtime/threadCritical.hpp"
97 #include "runtime/threadSMR.inline.hpp"
98 #include "runtime/threadStatisticalInfo.hpp"
99 #include "runtime/timer.hpp"
100 #include "runtime/timerTrace.hpp"
101 #include "runtime/vframe.inline.hpp"
102 #include "runtime/vframeArray.hpp"
103 #include "runtime/vframe_hp.hpp"
104 #include "runtime/vmThread.hpp"
105 #include "runtime/vmOperations.hpp"
106 #include "runtime/vm_version.hpp"
107 #include "services/attachListener.hpp"
108 #include "services/management.hpp"
109 #include "services/memTracker.hpp"
110 #include "services/threadService.hpp"
111 #include "utilities/align.hpp"
112 #include "utilities/copy.hpp"
113 #include "utilities/defaultStream.hpp"
114 #include "utilities/dtrace.hpp"
115 #include "utilities/events.hpp"
116 #include "utilities/macros.hpp"
117 #include "utilities/preserveException.hpp"
118 #include "utilities/singleWriterSynchronizer.hpp"
119 #include "utilities/vmError.hpp"
120 #if INCLUDE_JVMCI
121 #include "jvmci/jvmci.hpp"
122 #include "jvmci/jvmciEnv.hpp"
123 #endif
124 #ifdef COMPILER1
125 #include "c1/c1_Compiler.hpp"
126 #endif
127 #ifdef COMPILER2
128 #include "opto/c2compiler.hpp"
129 #include "opto/idealGraphPrinter.hpp"
130 #endif
131 #if INCLUDE_RTM_OPT
132 #include "runtime/rtmLocking.hpp"
133 #endif
134 #if INCLUDE_JFR
135 #include "jfr/jfr.hpp"
136 #endif
137
138 // Initialization after module runtime initialization
139 void universe_post_module_init(); // must happen after call_initPhase2
140
141 #ifdef DTRACE_ENABLED
142
143 // Only bother with this argument setup if dtrace is available
144
145 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
146 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
147
148 #define DTRACE_THREAD_PROBE(probe, javathread) \
149 { \
150 ResourceMark rm(this); \
151 int len = 0; \
152 const char* name = (javathread)->get_thread_name(); \
153 len = strlen(name); \
154 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
155 (char *) name, len, \
156 java_lang_Thread::thread_id((javathread)->threadObj()), \
157 (uintptr_t) (javathread)->osthread()->thread_id(), \
158 java_lang_Thread::is_daemon((javathread)->threadObj())); \
159 }
160
161 #else // ndef DTRACE_ENABLED
162
163 #define DTRACE_THREAD_PROBE(probe, javathread)
164
165 #endif // ndef DTRACE_ENABLED
166
167 #ifndef USE_LIBRARY_BASED_TLS_ONLY
168 // Current thread is maintained as a thread-local variable
169 THREAD_LOCAL_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 // Initial value of zero ==> never claimed.
242 _threads_do_token = 0;
243 _threads_hazard_ptr = NULL;
244 _threads_list_ptr = NULL;
245 _nested_threads_hazard_ptr_cnt = 0;
246 _rcu_counter = 0;
247
248 // the handle mark links itself to last_handle_mark
249 new HandleMark(this);
250
251 // plain initialization
252 debug_only(_owned_locks = NULL;)
253 NOT_PRODUCT(_allow_safepoint_count = 0;)
254 NOT_PRODUCT(_skip_gcalot = false;)
255 _jvmti_env_iteration_count = 0;
256 set_allocated_bytes(0);
257 _vm_operation_started_count = 0;
258 _vm_operation_completed_count = 0;
259 _current_pending_monitor = NULL;
260 _current_pending_monitor_is_from_java = true;
261 _current_waiting_monitor = NULL;
262 _num_nested_signal = 0;
263 omFreeList = NULL;
264 omFreeCount = 0;
265 omFreeProvision = 32;
266 omInUseList = NULL;
267 omInUseCount = 0;
268
269 #ifdef ASSERT
270 _visited_for_critical_count = false;
271 #endif
272
273 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
274 Monitor::_safepoint_check_sometimes);
275 _suspend_flags = 0;
276
277 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
278 _hashStateX = os::random();
279 _hashStateY = 842502087;
280 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
281 _hashStateW = 273326509;
282
283 _OnTrap = 0;
284 _Stalled = 0;
285 _TypeTag = 0x2BAD;
286
287 // Many of the following fields are effectively final - immutable
288 // Note that nascent threads can't use the Native Monitor-Mutex
289 // construct until the _MutexEvent is initialized ...
290 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
291 // we might instead use a stack of ParkEvents that we could provision on-demand.
292 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
293 // and ::Release()
294 _ParkEvent = ParkEvent::Allocate(this);
295 _SleepEvent = ParkEvent::Allocate(this);
296 _MuxEvent = ParkEvent::Allocate(this);
297
298 #ifdef CHECK_UNHANDLED_OOPS
299 if (CheckUnhandledOops) {
300 _unhandled_oops = new UnhandledOops(this);
301 }
302 #endif // CHECK_UNHANDLED_OOPS
303 #ifdef ASSERT
304 if (UseBiasedLocking) {
305 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
306 assert(this == _real_malloc_address ||
307 this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
308 "bug in forced alignment of thread objects");
309 }
310 #endif // ASSERT
311
312 // Notify the barrier set that a thread is being created. The initial
313 // thread is created before the barrier set is available. The call to
314 // BarrierSet::on_thread_create() for this thread is therefore deferred
315 // to BarrierSet::set_barrier_set().
316 BarrierSet* const barrier_set = BarrierSet::barrier_set();
317 if (barrier_set != NULL) {
318 barrier_set->on_thread_create(this);
319 } else {
320 // Only the main thread should be created before the barrier set
321 // and that happens just before Thread::current is set. No other thread
322 // can attach as the VM is not created yet, so they can't execute this code.
323 // If the main thread creates other threads before the barrier set that is an error.
324 assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
325 }
326 }
327
328 void Thread::initialize_thread_current() {
329 #ifndef USE_LIBRARY_BASED_TLS_ONLY
330 assert(_thr_current == NULL, "Thread::current already initialized");
331 _thr_current = this;
332 #endif
333 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
334 ThreadLocalStorage::set_thread(this);
335 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
336 }
337
338 void Thread::clear_thread_current() {
339 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
340 #ifndef USE_LIBRARY_BASED_TLS_ONLY
341 _thr_current = NULL;
342 #endif
343 ThreadLocalStorage::set_thread(NULL);
344 }
345
346 void Thread::record_stack_base_and_size() {
347 // Note: at this point, Thread object is not yet initialized. Do not rely on
348 // any members being initialized. Do not rely on Thread::current() being set.
349 // If possible, refrain from doing anything which may crash or assert since
350 // quite probably those crash dumps will be useless.
351 set_stack_base(os::current_stack_base());
352 set_stack_size(os::current_stack_size());
353
354 #ifdef SOLARIS
355 if (os::is_primordial_thread()) {
356 os::Solaris::correct_stack_boundaries_for_primordial_thread(this);
357 }
358 #endif
359
360 // Set stack limits after thread is initialized.
361 if (is_Java_thread()) {
362 ((JavaThread*) this)->set_stack_overflow_limit();
363 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
364 }
365 }
366
367 #if INCLUDE_NMT
368 void Thread::register_thread_stack_with_NMT() {
369 MemTracker::record_thread_stack(stack_end(), stack_size());
370 }
371 #endif // INCLUDE_NMT
372
373 void Thread::call_run() {
374 DEBUG_ONLY(_run_state = CALL_RUN;)
375
376 // At this point, Thread object should be fully initialized and
377 // Thread::current() should be set.
378
379 assert(Thread::current_or_null() != NULL, "current thread is unset");
380 assert(Thread::current_or_null() == this, "current thread is wrong");
381
382 // Perform common initialization actions
383
384 register_thread_stack_with_NMT();
385
386 JFR_ONLY(Jfr::on_thread_start(this);)
387
388 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
389 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
390 os::current_thread_id(), p2i(stack_base() - stack_size()),
391 p2i(stack_base()), stack_size()/1024);
392
393 // Perform <ChildClass> initialization actions
394 DEBUG_ONLY(_run_state = PRE_RUN;)
395 this->pre_run();
396
397 // Invoke <ChildClass>::run()
398 DEBUG_ONLY(_run_state = RUN;)
399 this->run();
400 // Returned from <ChildClass>::run(). Thread finished.
401
402 // Perform common tear-down actions
403
404 assert(Thread::current_or_null() != NULL, "current thread is unset");
405 assert(Thread::current_or_null() == this, "current thread is wrong");
406
407 // Perform <ChildClass> tear-down actions
408 DEBUG_ONLY(_run_state = POST_RUN;)
409 this->post_run();
410
411 // Note: at this point the thread object may already have deleted itself,
412 // so from here on do not dereference *this*. Not all thread types currently
413 // delete themselves when they terminate. But no thread should ever be deleted
414 // asynchronously with respect to its termination - that is what _run_state can
415 // be used to check.
416
417 assert(Thread::current_or_null() == NULL, "current thread still present");
418 }
419
420 Thread::~Thread() {
421
422 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
423 // get started due to errors etc. Any active thread should at least reach post_run
424 // before it is deleted (usually in post_run()).
425 assert(_run_state == PRE_CALL_RUN ||
426 _run_state == POST_RUN, "Active Thread deleted before post_run(): "
427 "_run_state=%d", (int)_run_state);
428
429 // Notify the barrier set that a thread is being destroyed. Note that a barrier
430 // set might not be available if we encountered errors during bootstrapping.
431 BarrierSet* const barrier_set = BarrierSet::barrier_set();
432 if (barrier_set != NULL) {
433 barrier_set->on_thread_destroy(this);
434 }
435
436 // stack_base can be NULL if the thread is never started or exited before
437 // record_stack_base_and_size called. Although, we would like to ensure
438 // that all started threads do call record_stack_base_and_size(), there is
439 // not proper way to enforce that.
440 #if INCLUDE_NMT
441 if (_stack_base != NULL) {
442 MemTracker::release_thread_stack(stack_end(), stack_size());
443 #ifdef ASSERT
444 set_stack_base(NULL);
445 #endif
446 }
447 #endif // INCLUDE_NMT
448
449 // deallocate data structures
450 delete resource_area();
451 // since the handle marks are using the handle area, we have to deallocated the root
452 // handle mark before deallocating the thread's handle area,
453 assert(last_handle_mark() != NULL, "check we have an element");
454 delete last_handle_mark();
455 assert(last_handle_mark() == NULL, "check we have reached the end");
456
457 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
458 // We NULL out the fields for good hygiene.
459 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
460 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
461 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
462
463 delete handle_area();
464 delete metadata_handles();
465
466 // SR_handler uses this as a termination indicator -
467 // needs to happen before os::free_thread()
468 delete _SR_lock;
469 _SR_lock = NULL;
470
471 // osthread() can be NULL, if creation of thread failed.
472 if (osthread() != NULL) os::free_thread(osthread());
473
474 // Clear Thread::current if thread is deleting itself and it has not
475 // already been done. This must be done before the memory is deallocated.
476 // Needed to ensure JNI correctly detects non-attached threads.
477 if (this == Thread::current_or_null()) {
478 Thread::clear_thread_current();
479 }
480
481 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
482 }
483
484 #ifdef ASSERT
485 // A JavaThread is considered "dangling" if it is not the current
486 // thread, has been added the Threads list, the system is not at a
487 // safepoint and the Thread is not "protected".
488 //
489 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
490 assert(!thread->is_Java_thread() || Thread::current() == thread ||
491 !((JavaThread *) thread)->on_thread_list() ||
492 SafepointSynchronize::is_at_safepoint() ||
493 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
494 "possibility of dangling Thread pointer");
495 }
496 #endif
497
498 ThreadPriority Thread::get_priority(const Thread* const thread) {
499 ThreadPriority priority;
500 // Can return an error!
501 (void)os::get_priority(thread, priority);
502 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
503 return priority;
504 }
505
506 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
507 debug_only(check_for_dangling_thread_pointer(thread);)
508 // Can return an error!
509 (void)os::set_priority(thread, priority);
510 }
511
512
513 void Thread::start(Thread* thread) {
514 // Start is different from resume in that its safety is guaranteed by context or
515 // being called from a Java method synchronized on the Thread object.
516 if (!DisableStartThread) {
517 if (thread->is_Java_thread()) {
518 // Initialize the thread state to RUNNABLE before starting this thread.
519 // Can not set it after the thread started because we do not know the
520 // exact thread state at that time. It could be in MONITOR_WAIT or
521 // in SLEEPING or some other state.
522 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
523 java_lang_Thread::RUNNABLE);
524 }
525 os::start_thread(thread);
526 }
527 }
528
529 // Enqueue a VM_Operation to do the job for us - sometime later
530 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
531 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
532 VMThread::execute(vm_stop);
533 }
534
535
536 // Check if an external suspend request has completed (or has been
537 // cancelled). Returns true if the thread is externally suspended and
538 // false otherwise.
539 //
540 // The bits parameter returns information about the code path through
541 // the routine. Useful for debugging:
542 //
543 // set in is_ext_suspend_completed():
544 // 0x00000001 - routine was entered
545 // 0x00000010 - routine return false at end
546 // 0x00000100 - thread exited (return false)
547 // 0x00000200 - suspend request cancelled (return false)
548 // 0x00000400 - thread suspended (return true)
549 // 0x00001000 - thread is in a suspend equivalent state (return true)
550 // 0x00002000 - thread is native and walkable (return true)
551 // 0x00004000 - thread is native_trans and walkable (needed retry)
552 //
553 // set in wait_for_ext_suspend_completion():
554 // 0x00010000 - routine was entered
555 // 0x00020000 - suspend request cancelled before loop (return false)
556 // 0x00040000 - thread suspended before loop (return true)
557 // 0x00080000 - suspend request cancelled in loop (return false)
558 // 0x00100000 - thread suspended in loop (return true)
559 // 0x00200000 - suspend not completed during retry loop (return false)
560
561 // Helper class for tracing suspend wait debug bits.
562 //
563 // 0x00000100 indicates that the target thread exited before it could
564 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
565 // 0x00080000 each indicate a cancelled suspend request so they don't
566 // count as wait failures either.
567 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
568
569 class TraceSuspendDebugBits : public StackObj {
570 private:
571 JavaThread * jt;
572 bool is_wait;
573 bool called_by_wait; // meaningful when !is_wait
574 uint32_t * bits;
575
576 public:
577 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
578 uint32_t *_bits) {
579 jt = _jt;
580 is_wait = _is_wait;
581 called_by_wait = _called_by_wait;
582 bits = _bits;
583 }
584
585 ~TraceSuspendDebugBits() {
586 if (!is_wait) {
587 #if 1
588 // By default, don't trace bits for is_ext_suspend_completed() calls.
589 // That trace is very chatty.
590 return;
591 #else
592 if (!called_by_wait) {
593 // If tracing for is_ext_suspend_completed() is enabled, then only
594 // trace calls to it from wait_for_ext_suspend_completion()
595 return;
596 }
597 #endif
598 }
599
600 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
601 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
602 MutexLocker ml(Threads_lock); // needed for get_thread_name()
603 ResourceMark rm;
604
605 tty->print_cr(
606 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
607 jt->get_thread_name(), *bits);
608
609 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
610 }
611 }
612 }
613 };
614 #undef DEBUG_FALSE_BITS
615
616
617 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
618 uint32_t *bits) {
619 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
620
621 bool did_trans_retry = false; // only do thread_in_native_trans retry once
622 bool do_trans_retry; // flag to force the retry
623
624 *bits |= 0x00000001;
625
626 do {
627 do_trans_retry = false;
628
629 if (is_exiting()) {
630 // Thread is in the process of exiting. This is always checked
631 // first to reduce the risk of dereferencing a freed JavaThread.
632 *bits |= 0x00000100;
633 return false;
634 }
635
636 if (!is_external_suspend()) {
637 // Suspend request is cancelled. This is always checked before
638 // is_ext_suspended() to reduce the risk of a rogue resume
639 // confusing the thread that made the suspend request.
640 *bits |= 0x00000200;
641 return false;
642 }
643
644 if (is_ext_suspended()) {
645 // thread is suspended
646 *bits |= 0x00000400;
647 return true;
648 }
649
650 // Now that we no longer do hard suspends of threads running
651 // native code, the target thread can be changing thread state
652 // while we are in this routine:
653 //
654 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
655 //
656 // We save a copy of the thread state as observed at this moment
657 // and make our decision about suspend completeness based on the
658 // copy. This closes the race where the thread state is seen as
659 // _thread_in_native_trans in the if-thread_blocked check, but is
660 // seen as _thread_blocked in if-thread_in_native_trans check.
661 JavaThreadState save_state = thread_state();
662
663 if (save_state == _thread_blocked && is_suspend_equivalent()) {
664 // If the thread's state is _thread_blocked and this blocking
665 // condition is known to be equivalent to a suspend, then we can
666 // consider the thread to be externally suspended. This means that
667 // the code that sets _thread_blocked has been modified to do
668 // self-suspension if the blocking condition releases. We also
669 // used to check for CONDVAR_WAIT here, but that is now covered by
670 // the _thread_blocked with self-suspension check.
671 //
672 // Return true since we wouldn't be here unless there was still an
673 // external suspend request.
674 *bits |= 0x00001000;
675 return true;
676 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
677 // Threads running native code will self-suspend on native==>VM/Java
678 // transitions. If its stack is walkable (should always be the case
679 // unless this function is called before the actual java_suspend()
680 // call), then the wait is done.
681 *bits |= 0x00002000;
682 return true;
683 } else if (!called_by_wait && !did_trans_retry &&
684 save_state == _thread_in_native_trans &&
685 frame_anchor()->walkable()) {
686 // The thread is transitioning from thread_in_native to another
687 // thread state. check_safepoint_and_suspend_for_native_trans()
688 // will force the thread to self-suspend. If it hasn't gotten
689 // there yet we may have caught the thread in-between the native
690 // code check above and the self-suspend. Lucky us. If we were
691 // called by wait_for_ext_suspend_completion(), then it
692 // will be doing the retries so we don't have to.
693 //
694 // Since we use the saved thread state in the if-statement above,
695 // there is a chance that the thread has already transitioned to
696 // _thread_blocked by the time we get here. In that case, we will
697 // make a single unnecessary pass through the logic below. This
698 // doesn't hurt anything since we still do the trans retry.
699
700 *bits |= 0x00004000;
701
702 // Once the thread leaves thread_in_native_trans for another
703 // thread state, we break out of this retry loop. We shouldn't
704 // need this flag to prevent us from getting back here, but
705 // sometimes paranoia is good.
706 did_trans_retry = true;
707
708 // We wait for the thread to transition to a more usable state.
709 for (int i = 1; i <= SuspendRetryCount; i++) {
710 // We used to do an "os::yield_all(i)" call here with the intention
711 // that yielding would increase on each retry. However, the parameter
712 // is ignored on Linux which means the yield didn't scale up. Waiting
713 // on the SR_lock below provides a much more predictable scale up for
714 // the delay. It also provides a simple/direct point to check for any
715 // safepoint requests from the VMThread
716
717 // temporarily drops SR_lock while doing wait with safepoint check
718 // (if we're a JavaThread - the WatcherThread can also call this)
719 // and increase delay with each retry
720 if (Thread::current()->is_Java_thread()) {
721 SR_lock()->wait(i * delay);
722 } else {
723 SR_lock()->wait_without_safepoint_check(i * delay);
724 }
725
726 // check the actual thread state instead of what we saved above
727 if (thread_state() != _thread_in_native_trans) {
728 // the thread has transitioned to another thread state so
729 // try all the checks (except this one) one more time.
730 do_trans_retry = true;
731 break;
732 }
733 } // end retry loop
734
735
736 }
737 } while (do_trans_retry);
738
739 *bits |= 0x00000010;
740 return false;
741 }
742
743 // Wait for an external suspend request to complete (or be cancelled).
744 // Returns true if the thread is externally suspended and false otherwise.
745 //
746 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
747 uint32_t *bits) {
748 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
749 false /* !called_by_wait */, bits);
750
751 // local flag copies to minimize SR_lock hold time
752 bool is_suspended;
753 bool pending;
754 uint32_t reset_bits;
755
756 // set a marker so is_ext_suspend_completed() knows we are the caller
757 *bits |= 0x00010000;
758
759 // We use reset_bits to reinitialize the bits value at the top of
760 // each retry loop. This allows the caller to make use of any
761 // unused bits for their own marking purposes.
762 reset_bits = *bits;
763
764 {
765 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
766 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
767 delay, bits);
768 pending = is_external_suspend();
769 }
770 // must release SR_lock to allow suspension to complete
771
772 if (!pending) {
773 // A cancelled suspend request is the only false return from
774 // is_ext_suspend_completed() that keeps us from entering the
775 // retry loop.
776 *bits |= 0x00020000;
777 return false;
778 }
779
780 if (is_suspended) {
781 *bits |= 0x00040000;
782 return true;
783 }
784
785 for (int i = 1; i <= retries; i++) {
786 *bits = reset_bits; // reinit to only track last retry
787
788 // We used to do an "os::yield_all(i)" call here with the intention
789 // that yielding would increase on each retry. However, the parameter
790 // is ignored on Linux which means the yield didn't scale up. Waiting
791 // on the SR_lock below provides a much more predictable scale up for
792 // the delay. It also provides a simple/direct point to check for any
793 // safepoint requests from the VMThread
794
795 {
796 Thread* t = Thread::current();
797 MonitorLocker ml(SR_lock(),
798 t->is_Java_thread() ? Mutex::_safepoint_check_flag : Mutex::_no_safepoint_check_flag);
799 // wait with safepoint check (if we're a JavaThread - the WatcherThread
800 // can also call this) and increase delay with each retry
801 ml.wait(i * delay);
802
803 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
804 delay, bits);
805
806 // It is possible for the external suspend request to be cancelled
807 // (by a resume) before the actual suspend operation is completed.
808 // Refresh our local copy to see if we still need to wait.
809 pending = is_external_suspend();
810 }
811
812 if (!pending) {
813 // A cancelled suspend request is the only false return from
814 // is_ext_suspend_completed() that keeps us from staying in the
815 // retry loop.
816 *bits |= 0x00080000;
817 return false;
818 }
819
820 if (is_suspended) {
821 *bits |= 0x00100000;
822 return true;
823 }
824 } // end retry loop
825
826 // thread did not suspend after all our retries
827 *bits |= 0x00200000;
828 return false;
829 }
830
831 // Called from API entry points which perform stack walking. If the
832 // associated JavaThread is the current thread, then wait_for_suspend
833 // is not used. Otherwise, it determines if we should wait for the
834 // "other" thread to complete external suspension. (NOTE: in future
835 // releases the suspension mechanism should be reimplemented so this
836 // is not necessary.)
837 //
838 bool
839 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
840 if (this != JavaThread::current()) {
841 // "other" threads require special handling.
842 if (wait_for_suspend) {
843 // We are allowed to wait for the external suspend to complete
844 // so give the other thread a chance to get suspended.
845 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
846 SuspendRetryDelay, bits)) {
847 // Didn't make it so let the caller know.
848 return false;
849 }
850 }
851 // We aren't allowed to wait for the external suspend to complete
852 // so if the other thread isn't externally suspended we need to
853 // let the caller know.
854 else if (!is_ext_suspend_completed_with_lock(bits)) {
855 return false;
856 }
857 }
858
859 return true;
860 }
861
862 #ifndef PRODUCT
863 void JavaThread::record_jump(address target, address instr, const char* file,
864 int line) {
865
866 // This should not need to be atomic as the only way for simultaneous
867 // updates is via interrupts. Even then this should be rare or non-existent
868 // and we don't care that much anyway.
869
870 int index = _jmp_ring_index;
871 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
872 _jmp_ring[index]._target = (intptr_t) target;
873 _jmp_ring[index]._instruction = (intptr_t) instr;
874 _jmp_ring[index]._file = file;
875 _jmp_ring[index]._line = line;
876 }
877 #endif // PRODUCT
878
879 void Thread::interrupt(Thread* thread) {
880 debug_only(check_for_dangling_thread_pointer(thread);)
881 os::interrupt(thread);
882 }
883
884 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
885 debug_only(check_for_dangling_thread_pointer(thread);)
886 // Note: If clear_interrupted==false, this simply fetches and
887 // returns the value of the field osthread()->interrupted().
888 return os::is_interrupted(thread, clear_interrupted);
889 }
890
891
892 // GC Support
893 bool Thread::claim_par_threads_do(uintx claim_token) {
894 uintx token = _threads_do_token;
895 if (token != claim_token) {
896 uintx res = Atomic::cmpxchg(claim_token, &_threads_do_token, token);
897 if (res == token) {
898 return true;
899 }
900 guarantee(res == claim_token, "invariant");
901 }
902 return false;
903 }
904
905 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
906 active_handles()->oops_do(f);
907 // Do oop for ThreadShadow
908 f->do_oop((oop*)&_pending_exception);
909 handle_area()->oops_do(f);
910
911 // We scan thread local monitor lists here, and the remaining global
912 // monitors in ObjectSynchronizer::oops_do().
913 ObjectSynchronizer::thread_local_used_oops_do(this, f);
914 }
915
916 void Thread::metadata_handles_do(void f(Metadata*)) {
917 // Only walk the Handles in Thread.
918 if (metadata_handles() != NULL) {
919 for (int i = 0; i< metadata_handles()->length(); i++) {
920 f(metadata_handles()->at(i));
921 }
922 }
923 }
924
925 void Thread::print_on(outputStream* st, bool print_extended_info) const {
926 // get_priority assumes osthread initialized
927 if (osthread() != NULL) {
928 int os_prio;
929 if (os::get_native_priority(this, &os_prio) == OS_OK) {
930 st->print("os_prio=%d ", os_prio);
931 }
932
933 st->print("cpu=%.2fms ",
934 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
935 );
936 st->print("elapsed=%.2fs ",
937 _statistical_info.getElapsedTime() / 1000.0
938 );
939 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
940 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
941 st->print("allocated=" SIZE_FORMAT "%s ",
942 byte_size_in_proper_unit(allocated_bytes),
943 proper_unit_for_byte_size(allocated_bytes)
944 );
945 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
946 }
947
948 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
949 osthread()->print_on(st);
950 }
951 ThreadsSMRSupport::print_info_on(this, st);
952 st->print(" ");
953 debug_only(if (WizardMode) print_owned_locks_on(st);)
954 }
955
956 void Thread::print() const { print_on(tty); }
957
958 // Thread::print_on_error() is called by fatal error handler. Don't use
959 // any lock or allocate memory.
960 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
961 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
962
963 if (is_VM_thread()) { st->print("VMThread"); }
964 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
965 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
966 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
967 else { st->print("Thread"); }
968
969 if (is_Named_thread()) {
970 st->print(" \"%s\"", name());
971 }
972
973 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
974 p2i(stack_end()), p2i(stack_base()));
975
976 if (osthread()) {
977 st->print(" [id=%d]", osthread()->thread_id());
978 }
979
980 ThreadsSMRSupport::print_info_on(this, st);
981 }
982
983 void Thread::print_value_on(outputStream* st) const {
984 if (is_Named_thread()) {
985 st->print(" \"%s\" ", name());
986 }
987 st->print(INTPTR_FORMAT, p2i(this)); // print address
988 }
989
990 #ifdef ASSERT
991 void Thread::print_owned_locks_on(outputStream* st) const {
992 Monitor *cur = _owned_locks;
993 if (cur == NULL) {
994 st->print(" (no locks) ");
995 } else {
996 st->print_cr(" Locks owned:");
997 while (cur) {
998 cur->print_on(st);
999 cur = cur->next();
1000 }
1001 }
1002 }
1003
1004 static int ref_use_count = 0;
1005
1006 bool Thread::owns_locks_but_compiled_lock() const {
1007 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1008 if (cur != Compile_lock) return true;
1009 }
1010 return false;
1011 }
1012
1013
1014 #endif
1015
1016 #ifndef PRODUCT
1017
1018 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
1019 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
1020 // no locks which allow_vm_block's are held
1021 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
1022 // Check if current thread is allowed to block at a safepoint
1023 if (!(_allow_safepoint_count == 0)) {
1024 fatal("Possible safepoint reached by thread that does not allow it");
1025 }
1026 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
1027 fatal("LEAF method calling lock?");
1028 }
1029
1030 #ifdef ASSERT
1031 if (potential_vm_operation && is_Java_thread()
1032 && !Universe::is_bootstrapping()) {
1033 // Make sure we do not hold any locks that the VM thread also uses.
1034 // This could potentially lead to deadlocks
1035 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1036 // Threads_lock is special, since the safepoint synchronization will not start before this is
1037 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
1038 // since it is used to transfer control between JavaThreads and the VMThread
1039 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
1040 if ((cur->allow_vm_block() &&
1041 cur != Threads_lock &&
1042 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
1043 cur != VMOperationRequest_lock &&
1044 cur != VMOperationQueue_lock) ||
1045 cur->rank() == Mutex::special) {
1046 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
1047 }
1048 }
1049 }
1050
1051 if (GCALotAtAllSafepoints) {
1052 // We could enter a safepoint here and thus have a gc
1053 InterfaceSupport::check_gc_alot();
1054 }
1055 #endif
1056 }
1057 #endif
1058
1059 bool Thread::is_in_stack(address adr) const {
1060 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1061 address end = os::current_stack_pointer();
1062 // Allow non Java threads to call this without stack_base
1063 if (_stack_base == NULL) return true;
1064 if (stack_base() >= adr && adr >= end) return true;
1065
1066 return false;
1067 }
1068
1069 bool Thread::is_in_usable_stack(address adr) const {
1070 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1071 size_t usable_stack_size = _stack_size - stack_guard_size;
1072
1073 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1074 }
1075
1076
1077 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1078 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1079 // used for compilation in the future. If that change is made, the need for these methods
1080 // should be revisited, and they should be removed if possible.
1081
1082 bool Thread::is_lock_owned(address adr) const {
1083 return on_local_stack(adr);
1084 }
1085
1086 bool Thread::set_as_starting_thread() {
1087 assert(_starting_thread == NULL, "already initialized: "
1088 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
1089 // NOTE: this must be called inside the main thread.
1090 DEBUG_ONLY(_starting_thread = this;)
1091 return os::create_main_thread((JavaThread*)this);
1092 }
1093
1094 static void initialize_class(Symbol* class_name, TRAPS) {
1095 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1096 InstanceKlass::cast(klass)->initialize(CHECK);
1097 }
1098
1099
1100 // Creates the initial ThreadGroup
1101 static Handle create_initial_thread_group(TRAPS) {
1102 Handle system_instance = JavaCalls::construct_new_instance(
1103 SystemDictionary::ThreadGroup_klass(),
1104 vmSymbols::void_method_signature(),
1105 CHECK_NH);
1106 Universe::set_system_thread_group(system_instance());
1107
1108 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1109 Handle main_instance = JavaCalls::construct_new_instance(
1110 SystemDictionary::ThreadGroup_klass(),
1111 vmSymbols::threadgroup_string_void_signature(),
1112 system_instance,
1113 string,
1114 CHECK_NH);
1115 return main_instance;
1116 }
1117
1118 // Creates the initial Thread
1119 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1120 TRAPS) {
1121 InstanceKlass* ik = SystemDictionary::Thread_klass();
1122 assert(ik->is_initialized(), "must be");
1123 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1124
1125 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1126 // constructor calls Thread.current(), which must be set here for the
1127 // initial thread.
1128 java_lang_Thread::set_thread(thread_oop(), thread);
1129 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1130 thread->set_threadObj(thread_oop());
1131
1132 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1133
1134 JavaValue result(T_VOID);
1135 JavaCalls::call_special(&result, thread_oop,
1136 ik,
1137 vmSymbols::object_initializer_name(),
1138 vmSymbols::threadgroup_string_void_signature(),
1139 thread_group,
1140 string,
1141 CHECK_NULL);
1142 return thread_oop();
1143 }
1144
1145 char java_runtime_name[128] = "";
1146 char java_runtime_version[128] = "";
1147
1148 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1149 static const char* get_java_runtime_name(TRAPS) {
1150 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1151 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1152 fieldDescriptor fd;
1153 bool found = k != NULL &&
1154 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1155 vmSymbols::string_signature(), &fd);
1156 if (found) {
1157 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1158 if (name_oop == NULL) {
1159 return NULL;
1160 }
1161 const char* name = java_lang_String::as_utf8_string(name_oop,
1162 java_runtime_name,
1163 sizeof(java_runtime_name));
1164 return name;
1165 } else {
1166 return NULL;
1167 }
1168 }
1169
1170 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1171 static const char* get_java_runtime_version(TRAPS) {
1172 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1173 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1174 fieldDescriptor fd;
1175 bool found = k != NULL &&
1176 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1177 vmSymbols::string_signature(), &fd);
1178 if (found) {
1179 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1180 if (name_oop == NULL) {
1181 return NULL;
1182 }
1183 const char* name = java_lang_String::as_utf8_string(name_oop,
1184 java_runtime_version,
1185 sizeof(java_runtime_version));
1186 return name;
1187 } else {
1188 return NULL;
1189 }
1190 }
1191
1192 // General purpose hook into Java code, run once when the VM is initialized.
1193 // The Java library method itself may be changed independently from the VM.
1194 static void call_postVMInitHook(TRAPS) {
1195 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1196 if (klass != NULL) {
1197 JavaValue result(T_VOID);
1198 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1199 vmSymbols::void_method_signature(),
1200 CHECK);
1201 }
1202 }
1203
1204 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1205 bool daemon, TRAPS) {
1206 assert(thread_group.not_null(), "thread group should be specified");
1207 assert(threadObj() == NULL, "should only create Java thread object once");
1208
1209 InstanceKlass* ik = SystemDictionary::Thread_klass();
1210 assert(ik->is_initialized(), "must be");
1211 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1212
1213 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1214 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1215 // constructor calls Thread.current(), which must be set here.
1216 java_lang_Thread::set_thread(thread_oop(), this);
1217 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1218 set_threadObj(thread_oop());
1219
1220 JavaValue result(T_VOID);
1221 if (thread_name != NULL) {
1222 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1223 // Thread gets assigned specified name and null target
1224 JavaCalls::call_special(&result,
1225 thread_oop,
1226 ik,
1227 vmSymbols::object_initializer_name(),
1228 vmSymbols::threadgroup_string_void_signature(),
1229 thread_group,
1230 name,
1231 THREAD);
1232 } else {
1233 // Thread gets assigned name "Thread-nnn" and null target
1234 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1235 JavaCalls::call_special(&result,
1236 thread_oop,
1237 ik,
1238 vmSymbols::object_initializer_name(),
1239 vmSymbols::threadgroup_runnable_void_signature(),
1240 thread_group,
1241 Handle(),
1242 THREAD);
1243 }
1244
1245
1246 if (daemon) {
1247 java_lang_Thread::set_daemon(thread_oop());
1248 }
1249
1250 if (HAS_PENDING_EXCEPTION) {
1251 return;
1252 }
1253
1254 Klass* group = SystemDictionary::ThreadGroup_klass();
1255 Handle threadObj(THREAD, this->threadObj());
1256
1257 JavaCalls::call_special(&result,
1258 thread_group,
1259 group,
1260 vmSymbols::add_method_name(),
1261 vmSymbols::thread_void_signature(),
1262 threadObj, // Arg 1
1263 THREAD);
1264 }
1265
1266 // List of all NonJavaThreads and safe iteration over that list.
1267
1268 class NonJavaThread::List {
1269 public:
1270 NonJavaThread* volatile _head;
1271 SingleWriterSynchronizer _protect;
1272
1273 List() : _head(NULL), _protect() {}
1274 };
1275
1276 NonJavaThread::List NonJavaThread::_the_list;
1277
1278 NonJavaThread::Iterator::Iterator() :
1279 _protect_enter(_the_list._protect.enter()),
1280 _current(OrderAccess::load_acquire(&_the_list._head))
1281 {}
1282
1283 NonJavaThread::Iterator::~Iterator() {
1284 _the_list._protect.exit(_protect_enter);
1285 }
1286
1287 void NonJavaThread::Iterator::step() {
1288 assert(!end(), "precondition");
1289 _current = OrderAccess::load_acquire(&_current->_next);
1290 }
1291
1292 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) {
1293 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!");
1294 }
1295
1296 NonJavaThread::~NonJavaThread() { }
1297
1298 void NonJavaThread::add_to_the_list() {
1299 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1300 // Initialize BarrierSet-related data before adding to list.
1301 BarrierSet::barrier_set()->on_thread_attach(this);
1302 OrderAccess::release_store(&_next, _the_list._head);
1303 OrderAccess::release_store(&_the_list._head, this);
1304 }
1305
1306 void NonJavaThread::remove_from_the_list() {
1307 {
1308 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1309 // Cleanup BarrierSet-related data before removing from list.
1310 BarrierSet::barrier_set()->on_thread_detach(this);
1311 NonJavaThread* volatile* p = &_the_list._head;
1312 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) {
1313 if (t == this) {
1314 *p = _next;
1315 break;
1316 }
1317 }
1318 }
1319 // Wait for any in-progress iterators. Concurrent synchronize is not
1320 // allowed, so do it while holding a dedicated lock. Outside and distinct
1321 // from NJTList_lock in case an iteration attempts to lock it.
1322 MutexLocker ml(NonJavaThreadsListSync_lock, Mutex::_no_safepoint_check_flag);
1323 _the_list._protect.synchronize();
1324 _next = NULL; // Safe to drop the link now.
1325 }
1326
1327 void NonJavaThread::pre_run() {
1328 add_to_the_list();
1329
1330 // This is slightly odd in that NamedThread is a subclass, but
1331 // in fact name() is defined in Thread
1332 assert(this->name() != NULL, "thread name was not set before it was started");
1333 this->set_native_thread_name(this->name());
1334 }
1335
1336 void NonJavaThread::post_run() {
1337 JFR_ONLY(Jfr::on_thread_exit(this);)
1338 remove_from_the_list();
1339 // Ensure thread-local-storage is cleared before termination.
1340 Thread::clear_thread_current();
1341 }
1342
1343 // NamedThread -- non-JavaThread subclasses with multiple
1344 // uniquely named instances should derive from this.
1345 NamedThread::NamedThread() :
1346 NonJavaThread(),
1347 _name(NULL),
1348 _processed_thread(NULL),
1349 _gc_id(GCId::undefined())
1350 {}
1351
1352 NamedThread::~NamedThread() {
1353 if (_name != NULL) {
1354 FREE_C_HEAP_ARRAY(char, _name);
1355 _name = NULL;
1356 }
1357 }
1358
1359 void NamedThread::set_name(const char* format, ...) {
1360 guarantee(_name == NULL, "Only get to set name once.");
1361 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1362 guarantee(_name != NULL, "alloc failure");
1363 va_list ap;
1364 va_start(ap, format);
1365 jio_vsnprintf(_name, max_name_len, format, ap);
1366 va_end(ap);
1367 }
1368
1369 void NamedThread::print_on(outputStream* st) const {
1370 st->print("\"%s\" ", name());
1371 Thread::print_on(st);
1372 st->cr();
1373 }
1374
1375
1376 // ======= WatcherThread ========
1377
1378 // The watcher thread exists to simulate timer interrupts. It should
1379 // be replaced by an abstraction over whatever native support for
1380 // timer interrupts exists on the platform.
1381
1382 WatcherThread* WatcherThread::_watcher_thread = NULL;
1383 bool WatcherThread::_startable = false;
1384 volatile bool WatcherThread::_should_terminate = false;
1385
1386 WatcherThread::WatcherThread() : NonJavaThread() {
1387 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1388 if (os::create_thread(this, os::watcher_thread)) {
1389 _watcher_thread = this;
1390
1391 // Set the watcher thread to the highest OS priority which should not be
1392 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1393 // is created. The only normal thread using this priority is the reference
1394 // handler thread, which runs for very short intervals only.
1395 // If the VMThread's priority is not lower than the WatcherThread profiling
1396 // will be inaccurate.
1397 os::set_priority(this, MaxPriority);
1398 if (!DisableStartThread) {
1399 os::start_thread(this);
1400 }
1401 }
1402 }
1403
1404 int WatcherThread::sleep() const {
1405 // The WatcherThread does not participate in the safepoint protocol
1406 // for the PeriodicTask_lock because it is not a JavaThread.
1407 MonitorLocker ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1408
1409 if (_should_terminate) {
1410 // check for termination before we do any housekeeping or wait
1411 return 0; // we did not sleep.
1412 }
1413
1414 // remaining will be zero if there are no tasks,
1415 // causing the WatcherThread to sleep until a task is
1416 // enrolled
1417 int remaining = PeriodicTask::time_to_wait();
1418 int time_slept = 0;
1419
1420 // we expect this to timeout - we only ever get unparked when
1421 // we should terminate or when a new task has been enrolled
1422 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1423
1424 jlong time_before_loop = os::javaTimeNanos();
1425
1426 while (true) {
1427 bool timedout = ml.wait(remaining);
1428 jlong now = os::javaTimeNanos();
1429
1430 if (remaining == 0) {
1431 // if we didn't have any tasks we could have waited for a long time
1432 // consider the time_slept zero and reset time_before_loop
1433 time_slept = 0;
1434 time_before_loop = now;
1435 } else {
1436 // need to recalculate since we might have new tasks in _tasks
1437 time_slept = (int) ((now - time_before_loop) / 1000000);
1438 }
1439
1440 // Change to task list or spurious wakeup of some kind
1441 if (timedout || _should_terminate) {
1442 break;
1443 }
1444
1445 remaining = PeriodicTask::time_to_wait();
1446 if (remaining == 0) {
1447 // Last task was just disenrolled so loop around and wait until
1448 // another task gets enrolled
1449 continue;
1450 }
1451
1452 remaining -= time_slept;
1453 if (remaining <= 0) {
1454 break;
1455 }
1456 }
1457
1458 return time_slept;
1459 }
1460
1461 void WatcherThread::run() {
1462 assert(this == watcher_thread(), "just checking");
1463
1464 this->set_active_handles(JNIHandleBlock::allocate_block());
1465 while (true) {
1466 assert(watcher_thread() == Thread::current(), "thread consistency check");
1467 assert(watcher_thread() == this, "thread consistency check");
1468
1469 // Calculate how long it'll be until the next PeriodicTask work
1470 // should be done, and sleep that amount of time.
1471 int time_waited = sleep();
1472
1473 if (VMError::is_error_reported()) {
1474 // A fatal error has happened, the error handler(VMError::report_and_die)
1475 // should abort JVM after creating an error log file. However in some
1476 // rare cases, the error handler itself might deadlock. Here periodically
1477 // check for error reporting timeouts, and if it happens, just proceed to
1478 // abort the VM.
1479
1480 // This code is in WatcherThread because WatcherThread wakes up
1481 // periodically so the fatal error handler doesn't need to do anything;
1482 // also because the WatcherThread is less likely to crash than other
1483 // threads.
1484
1485 for (;;) {
1486 // Note: we use naked sleep in this loop because we want to avoid using
1487 // any kind of VM infrastructure which may be broken at this point.
1488 if (VMError::check_timeout()) {
1489 // We hit error reporting timeout. Error reporting was interrupted and
1490 // will be wrapping things up now (closing files etc). Give it some more
1491 // time, then quit the VM.
1492 os::naked_short_sleep(200);
1493 // Print a message to stderr.
1494 fdStream err(defaultStream::output_fd());
1495 err.print_raw_cr("# [ timer expired, abort... ]");
1496 // skip atexit/vm_exit/vm_abort hooks
1497 os::die();
1498 }
1499
1500 // Wait a second, then recheck for timeout.
1501 os::naked_short_sleep(999);
1502 }
1503 }
1504
1505 if (_should_terminate) {
1506 // check for termination before posting the next tick
1507 break;
1508 }
1509
1510 PeriodicTask::real_time_tick(time_waited);
1511 }
1512
1513 // Signal that it is terminated
1514 {
1515 MutexLocker mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1516 _watcher_thread = NULL;
1517 Terminator_lock->notify_all();
1518 }
1519 }
1520
1521 void WatcherThread::start() {
1522 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1523
1524 if (watcher_thread() == NULL && _startable) {
1525 _should_terminate = false;
1526 // Create the single instance of WatcherThread
1527 new WatcherThread();
1528 }
1529 }
1530
1531 void WatcherThread::make_startable() {
1532 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1533 _startable = true;
1534 }
1535
1536 void WatcherThread::stop() {
1537 {
1538 // Follow normal safepoint aware lock enter protocol since the
1539 // WatcherThread is stopped by another JavaThread.
1540 MutexLocker ml(PeriodicTask_lock);
1541 _should_terminate = true;
1542
1543 WatcherThread* watcher = watcher_thread();
1544 if (watcher != NULL) {
1545 // unpark the WatcherThread so it can see that it should terminate
1546 watcher->unpark();
1547 }
1548 }
1549
1550 MonitorLocker mu(Terminator_lock);
1551
1552 while (watcher_thread() != NULL) {
1553 // This wait should make safepoint checks, wait without a timeout,
1554 // and wait as a suspend-equivalent condition.
1555 mu.wait(0, Mutex::_as_suspend_equivalent_flag);
1556 }
1557 }
1558
1559 void WatcherThread::unpark() {
1560 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1561 PeriodicTask_lock->notify();
1562 }
1563
1564 void WatcherThread::print_on(outputStream* st) const {
1565 st->print("\"%s\" ", name());
1566 Thread::print_on(st);
1567 st->cr();
1568 }
1569
1570 // ======= JavaThread ========
1571
1572 #if INCLUDE_JVMCI
1573
1574 jlong* JavaThread::_jvmci_old_thread_counters;
1575
1576 bool jvmci_counters_include(JavaThread* thread) {
1577 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1578 }
1579
1580 void JavaThread::collect_counters(jlong* array, int length) {
1581 assert(length == JVMCICounterSize, "wrong value");
1582 for (int i = 0; i < length; i++) {
1583 array[i] = _jvmci_old_thread_counters[i];
1584 }
1585 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
1586 if (jvmci_counters_include(tp)) {
1587 for (int i = 0; i < length; i++) {
1588 array[i] += tp->_jvmci_counters[i];
1589 }
1590 }
1591 }
1592 }
1593
1594 // Attempt to enlarge the array for per thread counters.
1595 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
1596 jlong* new_counters = NEW_C_HEAP_ARRAY(jlong, new_size, mtJVMCI);
1597 if (new_counters == NULL) {
1598 return NULL;
1599 }
1600 if (old_counters == NULL) {
1601 old_counters = new_counters;
1602 memset(old_counters, 0, sizeof(jlong) * new_size);
1603 } else {
1604 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
1605 new_counters[i] = old_counters[i];
1606 }
1607 if (new_size > current_size) {
1608 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
1609 }
1610 FREE_C_HEAP_ARRAY(jlong, old_counters);
1611 }
1612 return new_counters;
1613 }
1614
1615 // Attempt to enlarge the array for per thread counters.
1616 bool JavaThread::resize_counters(int current_size, int new_size) {
1617 jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
1618 if (new_counters == NULL) {
1619 return false;
1620 } else {
1621 _jvmci_counters = new_counters;
1622 return true;
1623 }
1624 }
1625
1626 class VM_JVMCIResizeCounters : public VM_Operation {
1627 private:
1628 int _new_size;
1629 bool _failed;
1630
1631 public:
1632 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
1633 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
1634 bool allow_nested_vm_operations() const { return true; }
1635 void doit() {
1636 // Resize the old thread counters array
1637 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
1638 if (new_counters == NULL) {
1639 _failed = true;
1640 return;
1641 } else {
1642 JavaThread::_jvmci_old_thread_counters = new_counters;
1643 }
1644
1645 // Now resize each threads array
1646 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
1647 if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
1648 _failed = true;
1649 break;
1650 }
1651 }
1652 if (!_failed) {
1653 JVMCICounterSize = _new_size;
1654 }
1655 }
1656
1657 bool failed() { return _failed; }
1658 };
1659
1660 bool JavaThread::resize_all_jvmci_counters(int new_size) {
1661 VM_JVMCIResizeCounters op(new_size);
1662 VMThread::execute(&op);
1663 return !op.failed();
1664 }
1665
1666 #endif // INCLUDE_JVMCI
1667
1668 // A JavaThread is a normal Java thread
1669
1670 void JavaThread::initialize() {
1671 // Initialize fields
1672
1673 set_saved_exception_pc(NULL);
1674 set_threadObj(NULL);
1675 _anchor.clear();
1676 set_entry_point(NULL);
1677 set_jni_functions(jni_functions());
1678 set_callee_target(NULL);
1679 set_vm_result(NULL);
1680 set_vm_result_2(NULL);
1681 set_vframe_array_head(NULL);
1682 set_vframe_array_last(NULL);
1683 set_deferred_locals(NULL);
1684 set_deopt_mark(NULL);
1685 set_deopt_compiled_method(NULL);
1686 clear_must_deopt_id();
1687 set_monitor_chunks(NULL);
1688 _on_thread_list = false;
1689 set_thread_state(_thread_new);
1690 _terminated = _not_terminated;
1691 _array_for_gc = NULL;
1692 _suspend_equivalent = false;
1693 _in_deopt_handler = 0;
1694 _doing_unsafe_access = false;
1695 _stack_guard_state = stack_guard_unused;
1696 #if INCLUDE_JVMCI
1697 _pending_monitorenter = false;
1698 _pending_deoptimization = -1;
1699 _pending_failed_speculation = 0;
1700 _pending_transfer_to_interpreter = false;
1701 _in_retryable_allocation = false;
1702 _jvmci._alternate_call_target = NULL;
1703 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1704 _jvmci_counters = NULL;
1705 if (JVMCICounterSize > 0) {
1706 resize_counters(0, (int) JVMCICounterSize);
1707 }
1708 #endif // INCLUDE_JVMCI
1709 _reserved_stack_activation = NULL; // stack base not known yet
1710 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1711 _exception_pc = 0;
1712 _exception_handler_pc = 0;
1713 _is_method_handle_return = 0;
1714 _jvmti_thread_state= NULL;
1715 _should_post_on_exceptions_flag = JNI_FALSE;
1716 _interp_only_mode = 0;
1717 _special_runtime_exit_condition = _no_async_condition;
1718 _pending_async_exception = NULL;
1719 _thread_stat = NULL;
1720 _thread_stat = new ThreadStatistics();
1721 _blocked_on_compilation = false;
1722 _jni_active_critical = 0;
1723 _pending_jni_exception_check_fn = NULL;
1724 _do_not_unlock_if_synchronized = false;
1725 _cached_monitor_info = NULL;
1726 _parker = Parker::Allocate(this);
1727
1728 #ifndef PRODUCT
1729 _jmp_ring_index = 0;
1730 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1731 record_jump(NULL, NULL, NULL, 0);
1732 }
1733 #endif // PRODUCT
1734
1735 // Setup safepoint state info for this thread
1736 ThreadSafepointState::create(this);
1737
1738 debug_only(_java_call_counter = 0);
1739
1740 // JVMTI PopFrame support
1741 _popframe_condition = popframe_inactive;
1742 _popframe_preserved_args = NULL;
1743 _popframe_preserved_args_size = 0;
1744 _frames_to_pop_failed_realloc = 0;
1745
1746 if (SafepointMechanism::uses_thread_local_poll()) {
1747 SafepointMechanism::initialize_header(this);
1748 }
1749
1750 _class_to_be_initialized = NULL;
1751
1752 pd_initialize();
1753 }
1754
1755 JavaThread::JavaThread(bool is_attaching_via_jni) :
1756 Thread() {
1757 initialize();
1758 if (is_attaching_via_jni) {
1759 _jni_attach_state = _attaching_via_jni;
1760 } else {
1761 _jni_attach_state = _not_attaching_via_jni;
1762 }
1763 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1764 }
1765
1766 bool JavaThread::reguard_stack(address cur_sp) {
1767 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1768 && _stack_guard_state != stack_guard_reserved_disabled) {
1769 return true; // Stack already guarded or guard pages not needed.
1770 }
1771
1772 if (register_stack_overflow()) {
1773 // For those architectures which have separate register and
1774 // memory stacks, we must check the register stack to see if
1775 // it has overflowed.
1776 return false;
1777 }
1778
1779 // Java code never executes within the yellow zone: the latter is only
1780 // there to provoke an exception during stack banging. If java code
1781 // is executing there, either StackShadowPages should be larger, or
1782 // some exception code in c1, c2 or the interpreter isn't unwinding
1783 // when it should.
1784 guarantee(cur_sp > stack_reserved_zone_base(),
1785 "not enough space to reguard - increase StackShadowPages");
1786 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1787 enable_stack_yellow_reserved_zone();
1788 if (reserved_stack_activation() != stack_base()) {
1789 set_reserved_stack_activation(stack_base());
1790 }
1791 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1792 set_reserved_stack_activation(stack_base());
1793 enable_stack_reserved_zone();
1794 }
1795 return true;
1796 }
1797
1798 bool JavaThread::reguard_stack(void) {
1799 return reguard_stack(os::current_stack_pointer());
1800 }
1801
1802
1803 void JavaThread::block_if_vm_exited() {
1804 if (_terminated == _vm_exited) {
1805 // _vm_exited is set at safepoint, and Threads_lock is never released
1806 // we will block here forever
1807 Threads_lock->lock_without_safepoint_check();
1808 ShouldNotReachHere();
1809 }
1810 }
1811
1812
1813 // Remove this ifdef when C1 is ported to the compiler interface.
1814 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1815 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1816
1817 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1818 Thread() {
1819 initialize();
1820 _jni_attach_state = _not_attaching_via_jni;
1821 set_entry_point(entry_point);
1822 // Create the native thread itself.
1823 // %note runtime_23
1824 os::ThreadType thr_type = os::java_thread;
1825 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1826 os::java_thread;
1827 os::create_thread(this, thr_type, stack_sz);
1828 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1829 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1830 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1831 // the exception consists of creating the exception object & initializing it, initialization
1832 // will leave the VM via a JavaCall and then all locks must be unlocked).
1833 //
1834 // The thread is still suspended when we reach here. Thread must be explicit started
1835 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1836 // by calling Threads:add. The reason why this is not done here, is because the thread
1837 // object must be fully initialized (take a look at JVM_Start)
1838 }
1839
1840 JavaThread::~JavaThread() {
1841
1842 // JSR166 -- return the parker to the free list
1843 Parker::Release(_parker);
1844 _parker = NULL;
1845
1846 // Free any remaining previous UnrollBlock
1847 vframeArray* old_array = vframe_array_last();
1848
1849 if (old_array != NULL) {
1850 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1851 old_array->set_unroll_block(NULL);
1852 delete old_info;
1853 delete old_array;
1854 }
1855
1856 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1857 if (deferred != NULL) {
1858 // This can only happen if thread is destroyed before deoptimization occurs.
1859 assert(deferred->length() != 0, "empty array!");
1860 do {
1861 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1862 deferred->remove_at(0);
1863 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1864 delete dlv;
1865 } while (deferred->length() != 0);
1866 delete deferred;
1867 }
1868
1869 // All Java related clean up happens in exit
1870 ThreadSafepointState::destroy(this);
1871 if (_thread_stat != NULL) delete _thread_stat;
1872
1873 #if INCLUDE_JVMCI
1874 if (JVMCICounterSize > 0) {
1875 if (jvmci_counters_include(this)) {
1876 for (int i = 0; i < JVMCICounterSize; i++) {
1877 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1878 }
1879 }
1880 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1881 }
1882 #endif // INCLUDE_JVMCI
1883 }
1884
1885
1886 // First JavaThread specific code executed by a new Java thread.
1887 void JavaThread::pre_run() {
1888 // empty - see comments in run()
1889 }
1890
1891 // The main routine called by a new Java thread. This isn't overridden
1892 // by subclasses, instead different subclasses define a different "entry_point"
1893 // which defines the actual logic for that kind of thread.
1894 void JavaThread::run() {
1895 // initialize thread-local alloc buffer related fields
1896 this->initialize_tlab();
1897
1898 // Used to test validity of stack trace backs.
1899 // This can't be moved into pre_run() else we invalidate
1900 // the requirement that thread_main_inner is lower on
1901 // the stack. Consequently all the initialization logic
1902 // stays here in run() rather than pre_run().
1903 this->record_base_of_stack_pointer();
1904
1905 this->create_stack_guard_pages();
1906
1907 this->cache_global_variables();
1908
1909 // Thread is now sufficiently initialized to be handled by the safepoint code as being
1910 // in the VM. Change thread state from _thread_new to _thread_in_vm
1911 ThreadStateTransition::transition(this, _thread_new, _thread_in_vm);
1912 // Before a thread is on the threads list it is always safe, so after leaving the
1913 // _thread_new we should emit a instruction barrier. The distance to modified code
1914 // from here is probably far enough, but this is consistent and safe.
1915 OrderAccess::cross_modify_fence();
1916
1917 assert(JavaThread::current() == this, "sanity check");
1918 assert(!Thread::current()->owns_locks(), "sanity check");
1919
1920 DTRACE_THREAD_PROBE(start, this);
1921
1922 // This operation might block. We call that after all safepoint checks for a new thread has
1923 // been completed.
1924 this->set_active_handles(JNIHandleBlock::allocate_block());
1925
1926 if (JvmtiExport::should_post_thread_life()) {
1927 JvmtiExport::post_thread_start(this);
1928
1929 }
1930
1931 // We call another function to do the rest so we are sure that the stack addresses used
1932 // from there will be lower than the stack base just computed.
1933 thread_main_inner();
1934 }
1935
1936 void JavaThread::thread_main_inner() {
1937 assert(JavaThread::current() == this, "sanity check");
1938 assert(this->threadObj() != NULL, "just checking");
1939
1940 // Execute thread entry point unless this thread has a pending exception
1941 // or has been stopped before starting.
1942 // Note: Due to JVM_StopThread we can have pending exceptions already!
1943 if (!this->has_pending_exception() &&
1944 !java_lang_Thread::is_stillborn(this->threadObj())) {
1945 {
1946 ResourceMark rm(this);
1947 this->set_native_thread_name(this->get_thread_name());
1948 }
1949 HandleMark hm(this);
1950 this->entry_point()(this, this);
1951 }
1952
1953 DTRACE_THREAD_PROBE(stop, this);
1954
1955 // Cleanup is handled in post_run()
1956 }
1957
1958 // Shared teardown for all JavaThreads
1959 void JavaThread::post_run() {
1960 this->exit(false);
1961 // Defer deletion to here to ensure 'this' is still referenceable in call_run
1962 // for any shared tear-down.
1963 this->smr_delete();
1964 }
1965
1966 static void ensure_join(JavaThread* thread) {
1967 // We do not need to grab the Threads_lock, since we are operating on ourself.
1968 Handle threadObj(thread, thread->threadObj());
1969 assert(threadObj.not_null(), "java thread object must exist");
1970 ObjectLocker lock(threadObj, thread);
1971 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1972 thread->clear_pending_exception();
1973 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1974 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1975 // Clear the native thread instance - this makes isAlive return false and allows the join()
1976 // to complete once we've done the notify_all below
1977 java_lang_Thread::set_thread(threadObj(), NULL);
1978 lock.notify_all(thread);
1979 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1980 thread->clear_pending_exception();
1981 }
1982
1983 static bool is_daemon(oop threadObj) {
1984 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
1985 }
1986
1987 // For any new cleanup additions, please check to see if they need to be applied to
1988 // cleanup_failed_attach_current_thread as well.
1989 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1990 assert(this == JavaThread::current(), "thread consistency check");
1991
1992 elapsedTimer _timer_exit_phase1;
1993 elapsedTimer _timer_exit_phase2;
1994 elapsedTimer _timer_exit_phase3;
1995 elapsedTimer _timer_exit_phase4;
1996
1997 if (log_is_enabled(Debug, os, thread, timer)) {
1998 _timer_exit_phase1.start();
1999 }
2000
2001 HandleMark hm(this);
2002 Handle uncaught_exception(this, this->pending_exception());
2003 this->clear_pending_exception();
2004 Handle threadObj(this, this->threadObj());
2005 assert(threadObj.not_null(), "Java thread object should be created");
2006
2007 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
2008 {
2009 EXCEPTION_MARK;
2010
2011 CLEAR_PENDING_EXCEPTION;
2012 }
2013 if (!destroy_vm) {
2014 if (uncaught_exception.not_null()) {
2015 EXCEPTION_MARK;
2016 // Call method Thread.dispatchUncaughtException().
2017 Klass* thread_klass = SystemDictionary::Thread_klass();
2018 JavaValue result(T_VOID);
2019 JavaCalls::call_virtual(&result,
2020 threadObj, thread_klass,
2021 vmSymbols::dispatchUncaughtException_name(),
2022 vmSymbols::throwable_void_signature(),
2023 uncaught_exception,
2024 THREAD);
2025 if (HAS_PENDING_EXCEPTION) {
2026 ResourceMark rm(this);
2027 jio_fprintf(defaultStream::error_stream(),
2028 "\nException: %s thrown from the UncaughtExceptionHandler"
2029 " in thread \"%s\"\n",
2030 pending_exception()->klass()->external_name(),
2031 get_thread_name());
2032 CLEAR_PENDING_EXCEPTION;
2033 }
2034 }
2035 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
2036
2037 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
2038 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
2039 // is deprecated anyhow.
2040 if (!is_Compiler_thread()) {
2041 int count = 3;
2042 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
2043 EXCEPTION_MARK;
2044 JavaValue result(T_VOID);
2045 Klass* thread_klass = SystemDictionary::Thread_klass();
2046 JavaCalls::call_virtual(&result,
2047 threadObj, thread_klass,
2048 vmSymbols::exit_method_name(),
2049 vmSymbols::void_method_signature(),
2050 THREAD);
2051 CLEAR_PENDING_EXCEPTION;
2052 }
2053 }
2054 // notify JVMTI
2055 if (JvmtiExport::should_post_thread_life()) {
2056 JvmtiExport::post_thread_end(this);
2057 }
2058
2059 // We have notified the agents that we are exiting, before we go on,
2060 // we must check for a pending external suspend request and honor it
2061 // in order to not surprise the thread that made the suspend request.
2062 while (true) {
2063 {
2064 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2065 if (!is_external_suspend()) {
2066 set_terminated(_thread_exiting);
2067 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
2068 break;
2069 }
2070 // Implied else:
2071 // Things get a little tricky here. We have a pending external
2072 // suspend request, but we are holding the SR_lock so we
2073 // can't just self-suspend. So we temporarily drop the lock
2074 // and then self-suspend.
2075 }
2076
2077 ThreadBlockInVM tbivm(this);
2078 java_suspend_self();
2079
2080 // We're done with this suspend request, but we have to loop around
2081 // and check again. Eventually we will get SR_lock without a pending
2082 // external suspend request and will be able to mark ourselves as
2083 // exiting.
2084 }
2085 // no more external suspends are allowed at this point
2086 } else {
2087 assert(!is_terminated() && !is_exiting(), "must not be exiting");
2088 // before_exit() has already posted JVMTI THREAD_END events
2089 }
2090
2091 if (log_is_enabled(Debug, os, thread, timer)) {
2092 _timer_exit_phase1.stop();
2093 _timer_exit_phase2.start();
2094 }
2095
2096 // Capture daemon status before the thread is marked as terminated.
2097 bool daemon = is_daemon(threadObj());
2098
2099 // Notify waiters on thread object. This has to be done after exit() is called
2100 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
2101 // group should have the destroyed bit set before waiters are notified).
2102 ensure_join(this);
2103 assert(!this->has_pending_exception(), "ensure_join should have cleared");
2104
2105 if (log_is_enabled(Debug, os, thread, timer)) {
2106 _timer_exit_phase2.stop();
2107 _timer_exit_phase3.start();
2108 }
2109 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
2110 // held by this thread must be released. The spec does not distinguish
2111 // between JNI-acquired and regular Java monitors. We can only see
2112 // regular Java monitors here if monitor enter-exit matching is broken.
2113 //
2114 // ensure_join() ignores IllegalThreadStateExceptions, and so does
2115 // ObjectSynchronizer::release_monitors_owned_by_thread().
2116 if (exit_type == jni_detach) {
2117 // Sanity check even though JNI DetachCurrentThread() would have
2118 // returned JNI_ERR if there was a Java frame. JavaThread exit
2119 // should be done executing Java code by the time we get here.
2120 assert(!this->has_last_Java_frame(),
2121 "should not have a Java frame when detaching or exiting");
2122 ObjectSynchronizer::release_monitors_owned_by_thread(this);
2123 assert(!this->has_pending_exception(), "release_monitors should have cleared");
2124 }
2125
2126 // These things needs to be done while we are still a Java Thread. Make sure that thread
2127 // is in a consistent state, in case GC happens
2128 JFR_ONLY(Jfr::on_thread_exit(this);)
2129
2130 if (active_handles() != NULL) {
2131 JNIHandleBlock* block = active_handles();
2132 set_active_handles(NULL);
2133 JNIHandleBlock::release_block(block);
2134 }
2135
2136 if (free_handle_block() != NULL) {
2137 JNIHandleBlock* block = free_handle_block();
2138 set_free_handle_block(NULL);
2139 JNIHandleBlock::release_block(block);
2140 }
2141
2142 // These have to be removed while this is still a valid thread.
2143 remove_stack_guard_pages();
2144
2145 if (UseTLAB) {
2146 tlab().retire();
2147 }
2148
2149 if (JvmtiEnv::environments_might_exist()) {
2150 JvmtiExport::cleanup_thread(this);
2151 }
2152
2153 // We must flush any deferred card marks and other various GC barrier
2154 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2155 // before removing a thread from the list of active threads.
2156 BarrierSet::barrier_set()->on_thread_detach(this);
2157
2158 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2159 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2160 os::current_thread_id());
2161
2162 if (log_is_enabled(Debug, os, thread, timer)) {
2163 _timer_exit_phase3.stop();
2164 _timer_exit_phase4.start();
2165 }
2166 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2167 Threads::remove(this, daemon);
2168
2169 if (log_is_enabled(Debug, os, thread, timer)) {
2170 _timer_exit_phase4.stop();
2171 ResourceMark rm(this);
2172 log_debug(os, thread, timer)("name='%s'"
2173 ", exit-phase1=" JLONG_FORMAT
2174 ", exit-phase2=" JLONG_FORMAT
2175 ", exit-phase3=" JLONG_FORMAT
2176 ", exit-phase4=" JLONG_FORMAT,
2177 get_thread_name(),
2178 _timer_exit_phase1.milliseconds(),
2179 _timer_exit_phase2.milliseconds(),
2180 _timer_exit_phase3.milliseconds(),
2181 _timer_exit_phase4.milliseconds());
2182 }
2183 }
2184
2185 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
2186 if (active_handles() != NULL) {
2187 JNIHandleBlock* block = active_handles();
2188 set_active_handles(NULL);
2189 JNIHandleBlock::release_block(block);
2190 }
2191
2192 if (free_handle_block() != NULL) {
2193 JNIHandleBlock* block = free_handle_block();
2194 set_free_handle_block(NULL);
2195 JNIHandleBlock::release_block(block);
2196 }
2197
2198 // These have to be removed while this is still a valid thread.
2199 remove_stack_guard_pages();
2200
2201 if (UseTLAB) {
2202 tlab().retire();
2203 }
2204
2205 BarrierSet::barrier_set()->on_thread_detach(this);
2206
2207 Threads::remove(this, is_daemon);
2208 this->smr_delete();
2209 }
2210
2211 JavaThread* JavaThread::active() {
2212 Thread* thread = Thread::current();
2213 if (thread->is_Java_thread()) {
2214 return (JavaThread*) thread;
2215 } else {
2216 assert(thread->is_VM_thread(), "this must be a vm thread");
2217 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2218 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2219 assert(ret->is_Java_thread(), "must be a Java thread");
2220 return ret;
2221 }
2222 }
2223
2224 bool JavaThread::is_lock_owned(address adr) const {
2225 if (Thread::is_lock_owned(adr)) return true;
2226
2227 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2228 if (chunk->contains(adr)) return true;
2229 }
2230
2231 return false;
2232 }
2233
2234
2235 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2236 chunk->set_next(monitor_chunks());
2237 set_monitor_chunks(chunk);
2238 }
2239
2240 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2241 guarantee(monitor_chunks() != NULL, "must be non empty");
2242 if (monitor_chunks() == chunk) {
2243 set_monitor_chunks(chunk->next());
2244 } else {
2245 MonitorChunk* prev = monitor_chunks();
2246 while (prev->next() != chunk) prev = prev->next();
2247 prev->set_next(chunk->next());
2248 }
2249 }
2250
2251 // JVM support.
2252
2253 // Note: this function shouldn't block if it's called in
2254 // _thread_in_native_trans state (such as from
2255 // check_special_condition_for_native_trans()).
2256 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2257
2258 if (has_last_Java_frame() && has_async_condition()) {
2259 // If we are at a polling page safepoint (not a poll return)
2260 // then we must defer async exception because live registers
2261 // will be clobbered by the exception path. Poll return is
2262 // ok because the call we a returning from already collides
2263 // with exception handling registers and so there is no issue.
2264 // (The exception handling path kills call result registers but
2265 // this is ok since the exception kills the result anyway).
2266
2267 if (is_at_poll_safepoint()) {
2268 // if the code we are returning to has deoptimized we must defer
2269 // the exception otherwise live registers get clobbered on the
2270 // exception path before deoptimization is able to retrieve them.
2271 //
2272 RegisterMap map(this, false);
2273 frame caller_fr = last_frame().sender(&map);
2274 assert(caller_fr.is_compiled_frame(), "what?");
2275 if (caller_fr.is_deoptimized_frame()) {
2276 log_info(exceptions)("deferred async exception at compiled safepoint");
2277 return;
2278 }
2279 }
2280 }
2281
2282 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2283 if (condition == _no_async_condition) {
2284 // Conditions have changed since has_special_runtime_exit_condition()
2285 // was called:
2286 // - if we were here only because of an external suspend request,
2287 // then that was taken care of above (or cancelled) so we are done
2288 // - if we were here because of another async request, then it has
2289 // been cleared between the has_special_runtime_exit_condition()
2290 // and now so again we are done
2291 return;
2292 }
2293
2294 // Check for pending async. exception
2295 if (_pending_async_exception != NULL) {
2296 // Only overwrite an already pending exception, if it is not a threadDeath.
2297 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2298
2299 // We cannot call Exceptions::_throw(...) here because we cannot block
2300 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2301
2302 LogTarget(Info, exceptions) lt;
2303 if (lt.is_enabled()) {
2304 ResourceMark rm;
2305 LogStream ls(lt);
2306 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2307 if (has_last_Java_frame()) {
2308 frame f = last_frame();
2309 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2310 }
2311 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2312 }
2313 _pending_async_exception = NULL;
2314 clear_has_async_exception();
2315 }
2316 }
2317
2318 if (check_unsafe_error &&
2319 condition == _async_unsafe_access_error && !has_pending_exception()) {
2320 condition = _no_async_condition; // done
2321 switch (thread_state()) {
2322 case _thread_in_vm: {
2323 JavaThread* THREAD = this;
2324 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2325 }
2326 case _thread_in_native: {
2327 ThreadInVMfromNative tiv(this);
2328 JavaThread* THREAD = this;
2329 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2330 }
2331 case _thread_in_Java: {
2332 ThreadInVMfromJava tiv(this);
2333 JavaThread* THREAD = this;
2334 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2335 }
2336 default:
2337 ShouldNotReachHere();
2338 }
2339 }
2340
2341 assert(condition == _no_async_condition || has_pending_exception() ||
2342 (!check_unsafe_error && condition == _async_unsafe_access_error),
2343 "must have handled the async condition, if no exception");
2344 }
2345
2346 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2347
2348 // Check for pending external suspend.
2349 if (is_external_suspend_with_lock()) {
2350 frame_anchor()->make_walkable(this);
2351 java_suspend_self_with_safepoint_check();
2352 }
2353
2354 // We might be here for reasons in addition to the self-suspend request
2355 // so check for other async requests.
2356 if (check_asyncs) {
2357 check_and_handle_async_exceptions();
2358 }
2359
2360 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2361 }
2362
2363 void JavaThread::send_thread_stop(oop java_throwable) {
2364 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2365 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2366 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2367
2368 // Do not throw asynchronous exceptions against the compiler thread
2369 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2370 if (!can_call_java()) return;
2371
2372 {
2373 // Actually throw the Throwable against the target Thread - however
2374 // only if there is no thread death exception installed already.
2375 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2376 // If the topmost frame is a runtime stub, then we are calling into
2377 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2378 // must deoptimize the caller before continuing, as the compiled exception handler table
2379 // may not be valid
2380 if (has_last_Java_frame()) {
2381 frame f = last_frame();
2382 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2383 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2384 RegisterMap reg_map(this, UseBiasedLocking);
2385 frame compiled_frame = f.sender(®_map);
2386 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2387 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2388 }
2389 }
2390 }
2391
2392 // Set async. pending exception in thread.
2393 set_pending_async_exception(java_throwable);
2394
2395 if (log_is_enabled(Info, exceptions)) {
2396 ResourceMark rm;
2397 log_info(exceptions)("Pending Async. exception installed of type: %s",
2398 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2399 }
2400 // for AbortVMOnException flag
2401 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2402 }
2403 }
2404
2405
2406 // Interrupt thread so it will wake up from a potential wait()
2407 Thread::interrupt(this);
2408 }
2409
2410 // External suspension mechanism.
2411 //
2412 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2413 // to any VM_locks and it is at a transition
2414 // Self-suspension will happen on the transition out of the vm.
2415 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2416 //
2417 // Guarantees on return:
2418 // + Target thread will not execute any new bytecode (that's why we need to
2419 // force a safepoint)
2420 // + Target thread will not enter any new monitors
2421 //
2422 void JavaThread::java_suspend() {
2423 ThreadsListHandle tlh;
2424 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2425 return;
2426 }
2427
2428 { MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2429 if (!is_external_suspend()) {
2430 // a racing resume has cancelled us; bail out now
2431 return;
2432 }
2433
2434 // suspend is done
2435 uint32_t debug_bits = 0;
2436 // Warning: is_ext_suspend_completed() may temporarily drop the
2437 // SR_lock to allow the thread to reach a stable thread state if
2438 // it is currently in a transient thread state.
2439 if (is_ext_suspend_completed(false /* !called_by_wait */,
2440 SuspendRetryDelay, &debug_bits)) {
2441 return;
2442 }
2443 }
2444
2445 if (Thread::current() == this) {
2446 // Safely self-suspend.
2447 // If we don't do this explicitly it will implicitly happen
2448 // before we transition back to Java, and on some other thread-state
2449 // transition paths, but not as we exit a JVM TI SuspendThread call.
2450 // As SuspendThread(current) must not return (until resumed) we must
2451 // self-suspend here.
2452 ThreadBlockInVM tbivm(this);
2453 java_suspend_self();
2454 } else {
2455 VM_ThreadSuspend vm_suspend;
2456 VMThread::execute(&vm_suspend);
2457 }
2458 }
2459
2460 // Part II of external suspension.
2461 // A JavaThread self suspends when it detects a pending external suspend
2462 // request. This is usually on transitions. It is also done in places
2463 // where continuing to the next transition would surprise the caller,
2464 // e.g., monitor entry.
2465 //
2466 // Returns the number of times that the thread self-suspended.
2467 //
2468 // Note: DO NOT call java_suspend_self() when you just want to block current
2469 // thread. java_suspend_self() is the second stage of cooperative
2470 // suspension for external suspend requests and should only be used
2471 // to complete an external suspend request.
2472 //
2473 int JavaThread::java_suspend_self() {
2474 assert(thread_state() == _thread_blocked, "wrong state for java_suspend_self()");
2475 int ret = 0;
2476
2477 // we are in the process of exiting so don't suspend
2478 if (is_exiting()) {
2479 clear_external_suspend();
2480 return ret;
2481 }
2482
2483 assert(_anchor.walkable() ||
2484 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2485 "must have walkable stack");
2486
2487 MonitorLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2488
2489 assert(!this->is_ext_suspended(),
2490 "a thread trying to self-suspend should not already be suspended");
2491
2492 if (this->is_suspend_equivalent()) {
2493 // If we are self-suspending as a result of the lifting of a
2494 // suspend equivalent condition, then the suspend_equivalent
2495 // flag is not cleared until we set the ext_suspended flag so
2496 // that wait_for_ext_suspend_completion() returns consistent
2497 // results.
2498 this->clear_suspend_equivalent();
2499 }
2500
2501 // A racing resume may have cancelled us before we grabbed SR_lock
2502 // above. Or another external suspend request could be waiting for us
2503 // by the time we return from SR_lock()->wait(). The thread
2504 // that requested the suspension may already be trying to walk our
2505 // stack and if we return now, we can change the stack out from under
2506 // it. This would be a "bad thing (TM)" and cause the stack walker
2507 // to crash. We stay self-suspended until there are no more pending
2508 // external suspend requests.
2509 while (is_external_suspend()) {
2510 ret++;
2511 this->set_ext_suspended();
2512
2513 // _ext_suspended flag is cleared by java_resume()
2514 while (is_ext_suspended()) {
2515 ml.wait();
2516 }
2517 }
2518 return ret;
2519 }
2520
2521 // Helper routine to set up the correct thread state before calling java_suspend_self.
2522 // This is called when regular thread-state transition helpers can't be used because
2523 // we can be in various states, in particular _thread_in_native_trans.
2524 // Because this thread is external suspended the safepoint code will count it as at
2525 // a safepoint, regardless of what its actual current thread-state is. But
2526 // is_ext_suspend_completed() may be waiting to see a thread transition from
2527 // _thread_in_native_trans to _thread_blocked. So we set the thread state directly
2528 // to _thread_blocked. The problem with setting thread state directly is that a
2529 // safepoint could happen just after java_suspend_self() returns after being resumed,
2530 // and the VM thread will see the _thread_blocked state. So we must check for a safepoint
2531 // after restoring the state to make sure we won't leave while a safepoint is in progress.
2532 // However, not all initial-states are allowed when performing a safepoint check, as we
2533 // should never be blocking at a safepoint whilst in those states. Of these 'bad' states
2534 // only _thread_in_native is possible when executing this code (based on our two callers).
2535 // A thread that is _thread_in_native is already safepoint-safe and so it doesn't matter
2536 // whether the VMThread sees the _thread_blocked state, or the _thread_in_native state,
2537 // and so we don't need the explicit safepoint check.
2538
2539 void JavaThread::java_suspend_self_with_safepoint_check() {
2540 assert(this == Thread::current(), "invariant");
2541 JavaThreadState state = thread_state();
2542 set_thread_state(_thread_blocked);
2543 java_suspend_self();
2544 set_thread_state_fence(state);
2545 // Since we are not using a regular thread-state transition helper here,
2546 // we must manually emit the instruction barrier after leaving a safe state.
2547 OrderAccess::cross_modify_fence();
2548 if (state != _thread_in_native) {
2549 SafepointMechanism::block_if_requested(this);
2550 }
2551 }
2552
2553 #ifdef ASSERT
2554 // Verify the JavaThread has not yet been published in the Threads::list, and
2555 // hence doesn't need protection from concurrent access at this stage.
2556 void JavaThread::verify_not_published() {
2557 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2558 // since an unpublished JavaThread doesn't participate in the
2559 // Thread-SMR protocol for keeping a ThreadsList alive.
2560 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2561 }
2562 #endif
2563
2564 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2565 // progress or when _suspend_flags is non-zero.
2566 // Current thread needs to self-suspend if there is a suspend request and/or
2567 // block if a safepoint is in progress.
2568 // Async exception ISN'T checked.
2569 // Note only the ThreadInVMfromNative transition can call this function
2570 // directly and when thread state is _thread_in_native_trans
2571 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2572 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2573
2574 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2575
2576 if (thread->is_external_suspend()) {
2577 thread->java_suspend_self_with_safepoint_check();
2578 } else {
2579 SafepointMechanism::block_if_requested(thread);
2580 }
2581
2582 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2583 }
2584
2585 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2586 // progress or when _suspend_flags is non-zero.
2587 // Current thread needs to self-suspend if there is a suspend request and/or
2588 // block if a safepoint is in progress.
2589 // Also check for pending async exception (not including unsafe access error).
2590 // Note only the native==>VM/Java barriers can call this function and when
2591 // thread state is _thread_in_native_trans.
2592 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2593 check_safepoint_and_suspend_for_native_trans(thread);
2594
2595 if (thread->has_async_exception()) {
2596 // We are in _thread_in_native_trans state, don't handle unsafe
2597 // access error since that may block.
2598 thread->check_and_handle_async_exceptions(false);
2599 }
2600 }
2601
2602 // This is a variant of the normal
2603 // check_special_condition_for_native_trans with slightly different
2604 // semantics for use by critical native wrappers. It does all the
2605 // normal checks but also performs the transition back into
2606 // thread_in_Java state. This is required so that critical natives
2607 // can potentially block and perform a GC if they are the last thread
2608 // exiting the GCLocker.
2609 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2610 check_special_condition_for_native_trans(thread);
2611
2612 // Finish the transition
2613 thread->set_thread_state(_thread_in_Java);
2614
2615 if (thread->do_critical_native_unlock()) {
2616 ThreadInVMfromJavaNoAsyncException tiv(thread);
2617 GCLocker::unlock_critical(thread);
2618 thread->clear_critical_native_unlock();
2619 }
2620 }
2621
2622 // We need to guarantee the Threads_lock here, since resumes are not
2623 // allowed during safepoint synchronization
2624 // Can only resume from an external suspension
2625 void JavaThread::java_resume() {
2626 assert_locked_or_safepoint(Threads_lock);
2627
2628 // Sanity check: thread is gone, has started exiting or the thread
2629 // was not externally suspended.
2630 ThreadsListHandle tlh;
2631 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2632 return;
2633 }
2634
2635 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2636
2637 clear_external_suspend();
2638
2639 if (is_ext_suspended()) {
2640 clear_ext_suspended();
2641 SR_lock()->notify_all();
2642 }
2643 }
2644
2645 size_t JavaThread::_stack_red_zone_size = 0;
2646 size_t JavaThread::_stack_yellow_zone_size = 0;
2647 size_t JavaThread::_stack_reserved_zone_size = 0;
2648 size_t JavaThread::_stack_shadow_zone_size = 0;
2649
2650 void JavaThread::create_stack_guard_pages() {
2651 if (!os::uses_stack_guard_pages() ||
2652 _stack_guard_state != stack_guard_unused ||
2653 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2654 log_info(os, thread)("Stack guard page creation for thread "
2655 UINTX_FORMAT " disabled", os::current_thread_id());
2656 return;
2657 }
2658 address low_addr = stack_end();
2659 size_t len = stack_guard_zone_size();
2660
2661 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2662 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2663
2664 int must_commit = os::must_commit_stack_guard_pages();
2665 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2666
2667 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2668 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2669 return;
2670 }
2671
2672 if (os::guard_memory((char *) low_addr, len)) {
2673 _stack_guard_state = stack_guard_enabled;
2674 } else {
2675 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2676 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2677 if (os::uncommit_memory((char *) low_addr, len)) {
2678 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2679 }
2680 return;
2681 }
2682
2683 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2684 PTR_FORMAT "-" PTR_FORMAT ".",
2685 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2686 }
2687
2688 void JavaThread::remove_stack_guard_pages() {
2689 assert(Thread::current() == this, "from different thread");
2690 if (_stack_guard_state == stack_guard_unused) return;
2691 address low_addr = stack_end();
2692 size_t len = stack_guard_zone_size();
2693
2694 if (os::must_commit_stack_guard_pages()) {
2695 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2696 _stack_guard_state = stack_guard_unused;
2697 } else {
2698 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2699 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2700 return;
2701 }
2702 } else {
2703 if (_stack_guard_state == stack_guard_unused) return;
2704 if (os::unguard_memory((char *) low_addr, len)) {
2705 _stack_guard_state = stack_guard_unused;
2706 } else {
2707 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2708 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2709 return;
2710 }
2711 }
2712
2713 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2714 PTR_FORMAT "-" PTR_FORMAT ".",
2715 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2716 }
2717
2718 void JavaThread::enable_stack_reserved_zone() {
2719 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state");
2720
2721 // The base notation is from the stack's point of view, growing downward.
2722 // We need to adjust it to work correctly with guard_memory()
2723 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2724
2725 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2726 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2727
2728 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2729 _stack_guard_state = stack_guard_enabled;
2730 } else {
2731 warning("Attempt to guard stack reserved zone failed.");
2732 }
2733 enable_register_stack_guard();
2734 }
2735
2736 void JavaThread::disable_stack_reserved_zone() {
2737 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state");
2738
2739 // Simply return if called for a thread that does not use guard pages.
2740 if (_stack_guard_state != stack_guard_enabled) return;
2741
2742 // The base notation is from the stack's point of view, growing downward.
2743 // We need to adjust it to work correctly with guard_memory()
2744 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2745
2746 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2747 _stack_guard_state = stack_guard_reserved_disabled;
2748 } else {
2749 warning("Attempt to unguard stack reserved zone failed.");
2750 }
2751 disable_register_stack_guard();
2752 }
2753
2754 void JavaThread::enable_stack_yellow_reserved_zone() {
2755 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2756 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2757
2758 // The base notation is from the stacks point of view, growing downward.
2759 // We need to adjust it to work correctly with guard_memory()
2760 address base = stack_red_zone_base();
2761
2762 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2763 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2764
2765 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2766 _stack_guard_state = stack_guard_enabled;
2767 } else {
2768 warning("Attempt to guard stack yellow zone failed.");
2769 }
2770 enable_register_stack_guard();
2771 }
2772
2773 void JavaThread::disable_stack_yellow_reserved_zone() {
2774 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2775 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2776
2777 // Simply return if called for a thread that does not use guard pages.
2778 if (_stack_guard_state == stack_guard_unused) return;
2779
2780 // The base notation is from the stacks point of view, growing downward.
2781 // We need to adjust it to work correctly with guard_memory()
2782 address base = stack_red_zone_base();
2783
2784 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2785 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2786 } else {
2787 warning("Attempt to unguard stack yellow zone failed.");
2788 }
2789 disable_register_stack_guard();
2790 }
2791
2792 void JavaThread::enable_stack_red_zone() {
2793 // The base notation is from the stacks point of view, growing downward.
2794 // We need to adjust it to work correctly with guard_memory()
2795 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2796 address base = stack_red_zone_base() - stack_red_zone_size();
2797
2798 guarantee(base < stack_base(), "Error calculating stack red zone");
2799 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2800
2801 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2802 warning("Attempt to guard stack red zone failed.");
2803 }
2804 }
2805
2806 void JavaThread::disable_stack_red_zone() {
2807 // The base notation is from the stacks point of view, growing downward.
2808 // We need to adjust it to work correctly with guard_memory()
2809 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2810 address base = stack_red_zone_base() - stack_red_zone_size();
2811 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2812 warning("Attempt to unguard stack red zone failed.");
2813 }
2814 }
2815
2816 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2817 // ignore is there is no stack
2818 if (!has_last_Java_frame()) return;
2819 // traverse the stack frames. Starts from top frame.
2820 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2821 frame* fr = fst.current();
2822 f(fr, fst.register_map());
2823 }
2824 }
2825
2826
2827 #ifndef PRODUCT
2828 // Deoptimization
2829 // Function for testing deoptimization
2830 void JavaThread::deoptimize() {
2831 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2832 StackFrameStream fst(this, UseBiasedLocking);
2833 bool deopt = false; // Dump stack only if a deopt actually happens.
2834 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2835 // Iterate over all frames in the thread and deoptimize
2836 for (; !fst.is_done(); fst.next()) {
2837 if (fst.current()->can_be_deoptimized()) {
2838
2839 if (only_at) {
2840 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2841 // consists of comma or carriage return separated numbers so
2842 // search for the current bci in that string.
2843 address pc = fst.current()->pc();
2844 nmethod* nm = (nmethod*) fst.current()->cb();
2845 ScopeDesc* sd = nm->scope_desc_at(pc);
2846 char buffer[8];
2847 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2848 size_t len = strlen(buffer);
2849 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2850 while (found != NULL) {
2851 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2852 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2853 // Check that the bci found is bracketed by terminators.
2854 break;
2855 }
2856 found = strstr(found + 1, buffer);
2857 }
2858 if (!found) {
2859 continue;
2860 }
2861 }
2862
2863 if (DebugDeoptimization && !deopt) {
2864 deopt = true; // One-time only print before deopt
2865 tty->print_cr("[BEFORE Deoptimization]");
2866 trace_frames();
2867 trace_stack();
2868 }
2869 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2870 }
2871 }
2872
2873 if (DebugDeoptimization && deopt) {
2874 tty->print_cr("[AFTER Deoptimization]");
2875 trace_frames();
2876 }
2877 }
2878
2879
2880 // Make zombies
2881 void JavaThread::make_zombies() {
2882 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2883 if (fst.current()->can_be_deoptimized()) {
2884 // it is a Java nmethod
2885 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2886 nm->make_not_entrant();
2887 }
2888 }
2889 }
2890 #endif // PRODUCT
2891
2892
2893 void JavaThread::deoptimized_wrt_marked_nmethods() {
2894 if (!has_last_Java_frame()) return;
2895 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2896 StackFrameStream fst(this, UseBiasedLocking);
2897 for (; !fst.is_done(); fst.next()) {
2898 if (fst.current()->should_be_deoptimized()) {
2899 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2900 }
2901 }
2902 }
2903
2904
2905 // If the caller is a NamedThread, then remember, in the current scope,
2906 // the given JavaThread in its _processed_thread field.
2907 class RememberProcessedThread: public StackObj {
2908 NamedThread* _cur_thr;
2909 public:
2910 RememberProcessedThread(JavaThread* jthr) {
2911 Thread* thread = Thread::current();
2912 if (thread->is_Named_thread()) {
2913 _cur_thr = (NamedThread *)thread;
2914 _cur_thr->set_processed_thread(jthr);
2915 } else {
2916 _cur_thr = NULL;
2917 }
2918 }
2919
2920 ~RememberProcessedThread() {
2921 if (_cur_thr) {
2922 _cur_thr->set_processed_thread(NULL);
2923 }
2924 }
2925 };
2926
2927 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2928 // Verify that the deferred card marks have been flushed.
2929 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2930
2931 // Traverse the GCHandles
2932 Thread::oops_do(f, cf);
2933
2934 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2935 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2936
2937 if (has_last_Java_frame()) {
2938 // Record JavaThread to GC thread
2939 RememberProcessedThread rpt(this);
2940
2941 // traverse the registered growable array
2942 if (_array_for_gc != NULL) {
2943 for (int index = 0; index < _array_for_gc->length(); index++) {
2944 f->do_oop(_array_for_gc->adr_at(index));
2945 }
2946 }
2947
2948 // Traverse the monitor chunks
2949 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2950 chunk->oops_do(f);
2951 }
2952
2953 // Traverse the execution stack
2954 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2955 fst.current()->oops_do(f, cf, fst.register_map());
2956 }
2957 }
2958
2959 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2960 // If we have deferred set_locals there might be oops waiting to be
2961 // written
2962 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2963 if (list != NULL) {
2964 for (int i = 0; i < list->length(); i++) {
2965 list->at(i)->oops_do(f);
2966 }
2967 }
2968
2969 // Traverse instance variables at the end since the GC may be moving things
2970 // around using this function
2971 f->do_oop((oop*) &_threadObj);
2972 f->do_oop((oop*) &_vm_result);
2973 f->do_oop((oop*) &_exception_oop);
2974 f->do_oop((oop*) &_pending_async_exception);
2975
2976 if (jvmti_thread_state() != NULL) {
2977 jvmti_thread_state()->oops_do(f);
2978 }
2979 }
2980
2981 #ifdef ASSERT
2982 void JavaThread::verify_states_for_handshake() {
2983 // This checks that the thread has a correct frame state during a handshake.
2984 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2985 (has_last_Java_frame() && java_call_counter() > 0),
2986 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
2987 has_last_Java_frame(), java_call_counter());
2988 }
2989 #endif
2990
2991 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2992 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2993 (has_last_Java_frame() && java_call_counter() > 0),
2994 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
2995 has_last_Java_frame(), java_call_counter());
2996
2997 if (has_last_Java_frame()) {
2998 // Traverse the execution stack
2999 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3000 fst.current()->nmethods_do(cf);
3001 }
3002 }
3003 }
3004
3005 void JavaThread::metadata_do(MetadataClosure* f) {
3006 if (has_last_Java_frame()) {
3007 // Traverse the execution stack to call f() on the methods in the stack
3008 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3009 fst.current()->metadata_do(f);
3010 }
3011 } else if (is_Compiler_thread()) {
3012 // need to walk ciMetadata in current compile tasks to keep alive.
3013 CompilerThread* ct = (CompilerThread*)this;
3014 if (ct->env() != NULL) {
3015 ct->env()->metadata_do(f);
3016 }
3017 CompileTask* task = ct->task();
3018 if (task != NULL) {
3019 task->metadata_do(f);
3020 }
3021 }
3022 }
3023
3024 // Printing
3025 const char* _get_thread_state_name(JavaThreadState _thread_state) {
3026 switch (_thread_state) {
3027 case _thread_uninitialized: return "_thread_uninitialized";
3028 case _thread_new: return "_thread_new";
3029 case _thread_new_trans: return "_thread_new_trans";
3030 case _thread_in_native: return "_thread_in_native";
3031 case _thread_in_native_trans: return "_thread_in_native_trans";
3032 case _thread_in_vm: return "_thread_in_vm";
3033 case _thread_in_vm_trans: return "_thread_in_vm_trans";
3034 case _thread_in_Java: return "_thread_in_Java";
3035 case _thread_in_Java_trans: return "_thread_in_Java_trans";
3036 case _thread_blocked: return "_thread_blocked";
3037 case _thread_blocked_trans: return "_thread_blocked_trans";
3038 default: return "unknown thread state";
3039 }
3040 }
3041
3042 #ifndef PRODUCT
3043 void JavaThread::print_thread_state_on(outputStream *st) const {
3044 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
3045 };
3046 void JavaThread::print_thread_state() const {
3047 print_thread_state_on(tty);
3048 }
3049 #endif // PRODUCT
3050
3051 // Called by Threads::print() for VM_PrintThreads operation
3052 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
3053 st->print_raw("\"");
3054 st->print_raw(get_thread_name());
3055 st->print_raw("\" ");
3056 oop thread_oop = threadObj();
3057 if (thread_oop != NULL) {
3058 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
3059 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
3060 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
3061 }
3062 Thread::print_on(st, print_extended_info);
3063 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
3064 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
3065 if (thread_oop != NULL) {
3066 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3067 }
3068 #ifndef PRODUCT
3069 _safepoint_state->print_on(st);
3070 #endif // PRODUCT
3071 if (is_Compiler_thread()) {
3072 CompileTask *task = ((CompilerThread*)this)->task();
3073 if (task != NULL) {
3074 st->print(" Compiling: ");
3075 task->print(st, NULL, true, false);
3076 } else {
3077 st->print(" No compile task");
3078 }
3079 st->cr();
3080 }
3081 }
3082
3083 void JavaThread::print() const { print_on(tty); }
3084
3085 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3086 st->print("%s", get_thread_name_string(buf, buflen));
3087 }
3088
3089 // Called by fatal error handler. The difference between this and
3090 // JavaThread::print() is that we can't grab lock or allocate memory.
3091 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3092 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3093 oop thread_obj = threadObj();
3094 if (thread_obj != NULL) {
3095 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3096 }
3097 st->print(" [");
3098 st->print("%s", _get_thread_state_name(_thread_state));
3099 if (osthread()) {
3100 st->print(", id=%d", osthread()->thread_id());
3101 }
3102 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3103 p2i(stack_end()), p2i(stack_base()));
3104 st->print("]");
3105
3106 ThreadsSMRSupport::print_info_on(this, st);
3107 return;
3108 }
3109
3110 // Verification
3111
3112 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3113
3114 void JavaThread::verify() {
3115 // Verify oops in the thread.
3116 oops_do(&VerifyOopClosure::verify_oop, NULL);
3117
3118 // Verify the stack frames.
3119 frames_do(frame_verify);
3120 }
3121
3122 // CR 6300358 (sub-CR 2137150)
3123 // Most callers of this method assume that it can't return NULL but a
3124 // thread may not have a name whilst it is in the process of attaching to
3125 // the VM - see CR 6412693, and there are places where a JavaThread can be
3126 // seen prior to having it's threadObj set (eg JNI attaching threads and
3127 // if vm exit occurs during initialization). These cases can all be accounted
3128 // for such that this method never returns NULL.
3129 const char* JavaThread::get_thread_name() const {
3130 #ifdef ASSERT
3131 // early safepoints can hit while current thread does not yet have TLS
3132 if (!SafepointSynchronize::is_at_safepoint()) {
3133 Thread *cur = Thread::current();
3134 if (!(cur->is_Java_thread() && cur == this)) {
3135 // Current JavaThreads are allowed to get their own name without
3136 // the Threads_lock.
3137 assert_locked_or_safepoint(Threads_lock);
3138 }
3139 }
3140 #endif // ASSERT
3141 return get_thread_name_string();
3142 }
3143
3144 // Returns a non-NULL representation of this thread's name, or a suitable
3145 // descriptive string if there is no set name
3146 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3147 const char* name_str;
3148 oop thread_obj = threadObj();
3149 if (thread_obj != NULL) {
3150 oop name = java_lang_Thread::name(thread_obj);
3151 if (name != NULL) {
3152 if (buf == NULL) {
3153 name_str = java_lang_String::as_utf8_string(name);
3154 } else {
3155 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3156 }
3157 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3158 name_str = "<no-name - thread is attaching>";
3159 } else {
3160 name_str = Thread::name();
3161 }
3162 } else {
3163 name_str = Thread::name();
3164 }
3165 assert(name_str != NULL, "unexpected NULL thread name");
3166 return name_str;
3167 }
3168
3169
3170 const char* JavaThread::get_threadgroup_name() const {
3171 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3172 oop thread_obj = threadObj();
3173 if (thread_obj != NULL) {
3174 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3175 if (thread_group != NULL) {
3176 // ThreadGroup.name can be null
3177 return java_lang_ThreadGroup::name(thread_group);
3178 }
3179 }
3180 return NULL;
3181 }
3182
3183 const char* JavaThread::get_parent_name() const {
3184 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3185 oop thread_obj = threadObj();
3186 if (thread_obj != NULL) {
3187 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3188 if (thread_group != NULL) {
3189 oop parent = java_lang_ThreadGroup::parent(thread_group);
3190 if (parent != NULL) {
3191 // ThreadGroup.name can be null
3192 return java_lang_ThreadGroup::name(parent);
3193 }
3194 }
3195 }
3196 return NULL;
3197 }
3198
3199 ThreadPriority JavaThread::java_priority() const {
3200 oop thr_oop = threadObj();
3201 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3202 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3203 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3204 return priority;
3205 }
3206
3207 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3208
3209 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3210 // Link Java Thread object <-> C++ Thread
3211
3212 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3213 // and put it into a new Handle. The Handle "thread_oop" can then
3214 // be used to pass the C++ thread object to other methods.
3215
3216 // Set the Java level thread object (jthread) field of the
3217 // new thread (a JavaThread *) to C++ thread object using the
3218 // "thread_oop" handle.
3219
3220 // Set the thread field (a JavaThread *) of the
3221 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3222
3223 Handle thread_oop(Thread::current(),
3224 JNIHandles::resolve_non_null(jni_thread));
3225 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3226 "must be initialized");
3227 set_threadObj(thread_oop());
3228 java_lang_Thread::set_thread(thread_oop(), this);
3229
3230 if (prio == NoPriority) {
3231 prio = java_lang_Thread::priority(thread_oop());
3232 assert(prio != NoPriority, "A valid priority should be present");
3233 }
3234
3235 // Push the Java priority down to the native thread; needs Threads_lock
3236 Thread::set_priority(this, prio);
3237
3238 // Add the new thread to the Threads list and set it in motion.
3239 // We must have threads lock in order to call Threads::add.
3240 // It is crucial that we do not block before the thread is
3241 // added to the Threads list for if a GC happens, then the java_thread oop
3242 // will not be visited by GC.
3243 Threads::add(this);
3244 }
3245
3246 oop JavaThread::current_park_blocker() {
3247 // Support for JSR-166 locks
3248 oop thread_oop = threadObj();
3249 if (thread_oop != NULL) {
3250 return java_lang_Thread::park_blocker(thread_oop);
3251 }
3252 return NULL;
3253 }
3254
3255
3256 void JavaThread::print_stack_on(outputStream* st) {
3257 if (!has_last_Java_frame()) return;
3258 ResourceMark rm;
3259 HandleMark hm;
3260
3261 RegisterMap reg_map(this);
3262 vframe* start_vf = last_java_vframe(®_map);
3263 int count = 0;
3264 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3265 if (f->is_java_frame()) {
3266 javaVFrame* jvf = javaVFrame::cast(f);
3267 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3268
3269 // Print out lock information
3270 if (JavaMonitorsInStackTrace) {
3271 jvf->print_lock_info_on(st, count);
3272 }
3273 } else {
3274 // Ignore non-Java frames
3275 }
3276
3277 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3278 count++;
3279 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3280 }
3281 }
3282
3283
3284 // JVMTI PopFrame support
3285 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3286 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3287 if (in_bytes(size_in_bytes) != 0) {
3288 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3289 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3290 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3291 }
3292 }
3293
3294 void* JavaThread::popframe_preserved_args() {
3295 return _popframe_preserved_args;
3296 }
3297
3298 ByteSize JavaThread::popframe_preserved_args_size() {
3299 return in_ByteSize(_popframe_preserved_args_size);
3300 }
3301
3302 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3303 int sz = in_bytes(popframe_preserved_args_size());
3304 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3305 return in_WordSize(sz / wordSize);
3306 }
3307
3308 void JavaThread::popframe_free_preserved_args() {
3309 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3310 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3311 _popframe_preserved_args = NULL;
3312 _popframe_preserved_args_size = 0;
3313 }
3314
3315 #ifndef PRODUCT
3316
3317 void JavaThread::trace_frames() {
3318 tty->print_cr("[Describe stack]");
3319 int frame_no = 1;
3320 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3321 tty->print(" %d. ", frame_no++);
3322 fst.current()->print_value_on(tty, this);
3323 tty->cr();
3324 }
3325 }
3326
3327 class PrintAndVerifyOopClosure: public OopClosure {
3328 protected:
3329 template <class T> inline void do_oop_work(T* p) {
3330 oop obj = RawAccess<>::oop_load(p);
3331 if (obj == NULL) return;
3332 tty->print(INTPTR_FORMAT ": ", p2i(p));
3333 if (oopDesc::is_oop_or_null(obj)) {
3334 if (obj->is_objArray()) {
3335 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3336 } else {
3337 obj->print();
3338 }
3339 } else {
3340 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3341 }
3342 tty->cr();
3343 }
3344 public:
3345 virtual void do_oop(oop* p) { do_oop_work(p); }
3346 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3347 };
3348
3349
3350 static void oops_print(frame* f, const RegisterMap *map) {
3351 PrintAndVerifyOopClosure print;
3352 f->print_value();
3353 f->oops_do(&print, NULL, (RegisterMap*)map);
3354 }
3355
3356 // Print our all the locations that contain oops and whether they are
3357 // valid or not. This useful when trying to find the oldest frame
3358 // where an oop has gone bad since the frame walk is from youngest to
3359 // oldest.
3360 void JavaThread::trace_oops() {
3361 tty->print_cr("[Trace oops]");
3362 frames_do(oops_print);
3363 }
3364
3365
3366 #ifdef ASSERT
3367 // Print or validate the layout of stack frames
3368 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3369 ResourceMark rm;
3370 PRESERVE_EXCEPTION_MARK;
3371 FrameValues values;
3372 int frame_no = 0;
3373 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3374 fst.current()->describe(values, ++frame_no);
3375 if (depth == frame_no) break;
3376 }
3377 if (validate_only) {
3378 values.validate();
3379 } else {
3380 tty->print_cr("[Describe stack layout]");
3381 values.print(this);
3382 }
3383 }
3384 #endif
3385
3386 void JavaThread::trace_stack_from(vframe* start_vf) {
3387 ResourceMark rm;
3388 int vframe_no = 1;
3389 for (vframe* f = start_vf; f; f = f->sender()) {
3390 if (f->is_java_frame()) {
3391 javaVFrame::cast(f)->print_activation(vframe_no++);
3392 } else {
3393 f->print();
3394 }
3395 if (vframe_no > StackPrintLimit) {
3396 tty->print_cr("...<more frames>...");
3397 return;
3398 }
3399 }
3400 }
3401
3402
3403 void JavaThread::trace_stack() {
3404 if (!has_last_Java_frame()) return;
3405 ResourceMark rm;
3406 HandleMark hm;
3407 RegisterMap reg_map(this);
3408 trace_stack_from(last_java_vframe(®_map));
3409 }
3410
3411
3412 #endif // PRODUCT
3413
3414
3415 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3416 assert(reg_map != NULL, "a map must be given");
3417 frame f = last_frame();
3418 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3419 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3420 }
3421 return NULL;
3422 }
3423
3424
3425 Klass* JavaThread::security_get_caller_class(int depth) {
3426 vframeStream vfst(this);
3427 vfst.security_get_caller_frame(depth);
3428 if (!vfst.at_end()) {
3429 return vfst.method()->method_holder();
3430 }
3431 return NULL;
3432 }
3433
3434 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3435 assert(thread->is_Compiler_thread(), "must be compiler thread");
3436 CompileBroker::compiler_thread_loop();
3437 }
3438
3439 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3440 NMethodSweeper::sweeper_loop();
3441 }
3442
3443 // Create a CompilerThread
3444 CompilerThread::CompilerThread(CompileQueue* queue,
3445 CompilerCounters* counters)
3446 : JavaThread(&compiler_thread_entry) {
3447 _env = NULL;
3448 _log = NULL;
3449 _task = NULL;
3450 _queue = queue;
3451 _counters = counters;
3452 _buffer_blob = NULL;
3453 _compiler = NULL;
3454
3455 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3456 resource_area()->bias_to(mtCompiler);
3457
3458 #ifndef PRODUCT
3459 _ideal_graph_printer = NULL;
3460 #endif
3461 }
3462
3463 CompilerThread::~CompilerThread() {
3464 // Delete objects which were allocated on heap.
3465 delete _counters;
3466 }
3467
3468 bool CompilerThread::can_call_java() const {
3469 return _compiler != NULL && _compiler->is_jvmci();
3470 }
3471
3472 // Create sweeper thread
3473 CodeCacheSweeperThread::CodeCacheSweeperThread()
3474 : JavaThread(&sweeper_thread_entry) {
3475 _scanned_compiled_method = NULL;
3476 }
3477
3478 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3479 JavaThread::oops_do(f, cf);
3480 if (_scanned_compiled_method != NULL && cf != NULL) {
3481 // Safepoints can occur when the sweeper is scanning an nmethod so
3482 // process it here to make sure it isn't unloaded in the middle of
3483 // a scan.
3484 cf->do_code_blob(_scanned_compiled_method);
3485 }
3486 }
3487
3488 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3489 JavaThread::nmethods_do(cf);
3490 if (_scanned_compiled_method != NULL && cf != NULL) {
3491 // Safepoints can occur when the sweeper is scanning an nmethod so
3492 // process it here to make sure it isn't unloaded in the middle of
3493 // a scan.
3494 cf->do_code_blob(_scanned_compiled_method);
3495 }
3496 }
3497
3498
3499 // ======= Threads ========
3500
3501 // The Threads class links together all active threads, and provides
3502 // operations over all threads. It is protected by the Threads_lock,
3503 // which is also used in other global contexts like safepointing.
3504 // ThreadsListHandles are used to safely perform operations on one
3505 // or more threads without the risk of the thread exiting during the
3506 // operation.
3507 //
3508 // Note: The Threads_lock is currently more widely used than we
3509 // would like. We are actively migrating Threads_lock uses to other
3510 // mechanisms in order to reduce Threads_lock contention.
3511
3512 int Threads::_number_of_threads = 0;
3513 int Threads::_number_of_non_daemon_threads = 0;
3514 int Threads::_return_code = 0;
3515 uintx Threads::_thread_claim_token = 1; // Never zero.
3516 size_t JavaThread::_stack_size_at_create = 0;
3517
3518 #ifdef ASSERT
3519 bool Threads::_vm_complete = false;
3520 #endif
3521
3522 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3523 Prefetch::read((void*)addr, prefetch_interval);
3524 return *addr;
3525 }
3526
3527 // Possibly the ugliest for loop the world has seen. C++ does not allow
3528 // multiple types in the declaration section of the for loop. In this case
3529 // we are only dealing with pointers and hence can cast them. It looks ugly
3530 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3531 #define DO_JAVA_THREADS(LIST, X) \
3532 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3533 *MACRO_list = (JavaThread*)(LIST), \
3534 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3535 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3536 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3537 MACRO_current_p != MACRO_end; \
3538 MACRO_current_p++, \
3539 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3540
3541 // All JavaThreads
3542 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3543
3544 // All NonJavaThreads (i.e., every non-JavaThread in the system).
3545 void Threads::non_java_threads_do(ThreadClosure* tc) {
3546 NoSafepointVerifier nsv(!SafepointSynchronize::is_at_safepoint(), false);
3547 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
3548 tc->do_thread(njti.current());
3549 }
3550 }
3551
3552 // All JavaThreads
3553 void Threads::java_threads_do(ThreadClosure* tc) {
3554 assert_locked_or_safepoint(Threads_lock);
3555 // ALL_JAVA_THREADS iterates through all JavaThreads.
3556 ALL_JAVA_THREADS(p) {
3557 tc->do_thread(p);
3558 }
3559 }
3560
3561 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3562 assert_locked_or_safepoint(Threads_lock);
3563 java_threads_do(tc);
3564 tc->do_thread(VMThread::vm_thread());
3565 }
3566
3567 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3568 void Threads::threads_do(ThreadClosure* tc) {
3569 assert_locked_or_safepoint(Threads_lock);
3570 java_threads_do(tc);
3571 non_java_threads_do(tc);
3572 }
3573
3574 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3575 uintx claim_token = Threads::thread_claim_token();
3576 ALL_JAVA_THREADS(p) {
3577 if (p->claim_threads_do(is_par, claim_token)) {
3578 tc->do_thread(p);
3579 }
3580 }
3581 VMThread* vmt = VMThread::vm_thread();
3582 if (vmt->claim_threads_do(is_par, claim_token)) {
3583 tc->do_thread(vmt);
3584 }
3585 }
3586
3587 // The system initialization in the library has three phases.
3588 //
3589 // Phase 1: java.lang.System class initialization
3590 // java.lang.System is a primordial class loaded and initialized
3591 // by the VM early during startup. java.lang.System.<clinit>
3592 // only does registerNatives and keeps the rest of the class
3593 // initialization work later until thread initialization completes.
3594 //
3595 // System.initPhase1 initializes the system properties, the static
3596 // fields in, out, and err. Set up java signal handlers, OS-specific
3597 // system settings, and thread group of the main thread.
3598 static void call_initPhase1(TRAPS) {
3599 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3600 JavaValue result(T_VOID);
3601 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3602 vmSymbols::void_method_signature(), CHECK);
3603 }
3604
3605 // Phase 2. Module system initialization
3606 // This will initialize the module system. Only java.base classes
3607 // can be loaded until phase 2 completes.
3608 //
3609 // Call System.initPhase2 after the compiler initialization and jsr292
3610 // classes get initialized because module initialization runs a lot of java
3611 // code, that for performance reasons, should be compiled. Also, this will
3612 // enable the startup code to use lambda and other language features in this
3613 // phase and onward.
3614 //
3615 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3616 static void call_initPhase2(TRAPS) {
3617 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3618
3619 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3620
3621 JavaValue result(T_INT);
3622 JavaCallArguments args;
3623 args.push_int(DisplayVMOutputToStderr);
3624 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3625 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3626 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3627 if (result.get_jint() != JNI_OK) {
3628 vm_exit_during_initialization(); // no message or exception
3629 }
3630
3631 universe_post_module_init();
3632 }
3633
3634 // Phase 3. final setup - set security manager, system class loader and TCCL
3635 //
3636 // This will instantiate and set the security manager, set the system class
3637 // loader as well as the thread context class loader. The security manager
3638 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3639 // other modules or the application's classpath.
3640 static void call_initPhase3(TRAPS) {
3641 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3642 JavaValue result(T_VOID);
3643 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3644 vmSymbols::void_method_signature(), CHECK);
3645 }
3646
3647 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3648 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3649
3650 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3651 create_vm_init_libraries();
3652 }
3653
3654 initialize_class(vmSymbols::java_lang_String(), CHECK);
3655
3656 // Inject CompactStrings value after the static initializers for String ran.
3657 java_lang_String::set_compact_strings(CompactStrings);
3658
3659 // Initialize java_lang.System (needed before creating the thread)
3660 initialize_class(vmSymbols::java_lang_System(), CHECK);
3661 // The VM creates & returns objects of this class. Make sure it's initialized.
3662 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3663 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3664 Handle thread_group = create_initial_thread_group(CHECK);
3665 Universe::set_main_thread_group(thread_group());
3666 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3667 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3668 main_thread->set_threadObj(thread_object);
3669
3670 // Set thread status to running since main thread has
3671 // been started and running.
3672 java_lang_Thread::set_thread_status(thread_object,
3673 java_lang_Thread::RUNNABLE);
3674
3675 // The VM creates objects of this class.
3676 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3677
3678 #ifdef ASSERT
3679 InstanceKlass *k = SystemDictionary::UnsafeConstants_klass();
3680 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
3681 #endif
3682
3683 // initialize the hardware-specific constants needed by Unsafe
3684 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
3685 jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
3686
3687 // The VM preresolves methods to these classes. Make sure that they get initialized
3688 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3689 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3690
3691 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3692 call_initPhase1(CHECK);
3693
3694 // get the Java runtime name after java.lang.System is initialized
3695 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3696 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3697
3698 // an instance of OutOfMemory exception has been allocated earlier
3699 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3700 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3701 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3702 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3703 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3704 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3705 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3706 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3707
3708 // Eager box cache initialization only if AOT is on and any library is loaded.
3709 AOTLoader::initialize_box_caches(CHECK);
3710 }
3711
3712 void Threads::initialize_jsr292_core_classes(TRAPS) {
3713 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3714
3715 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3716 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3717 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3718 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3719 }
3720
3721 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3722 extern void JDK_Version_init();
3723
3724 // Preinitialize version info.
3725 VM_Version::early_initialize();
3726
3727 // Check version
3728 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3729
3730 // Initialize library-based TLS
3731 ThreadLocalStorage::init();
3732
3733 // Initialize the output stream module
3734 ostream_init();
3735
3736 // Process java launcher properties.
3737 Arguments::process_sun_java_launcher_properties(args);
3738
3739 // Initialize the os module
3740 os::init();
3741
3742 // Record VM creation timing statistics
3743 TraceVmCreationTime create_vm_timer;
3744 create_vm_timer.start();
3745
3746 // Initialize system properties.
3747 Arguments::init_system_properties();
3748
3749 // So that JDK version can be used as a discriminator when parsing arguments
3750 JDK_Version_init();
3751
3752 // Update/Initialize System properties after JDK version number is known
3753 Arguments::init_version_specific_system_properties();
3754
3755 // Make sure to initialize log configuration *before* parsing arguments
3756 LogConfiguration::initialize(create_vm_timer.begin_time());
3757
3758 // Parse arguments
3759 // Note: this internally calls os::init_container_support()
3760 jint parse_result = Arguments::parse(args);
3761 if (parse_result != JNI_OK) return parse_result;
3762
3763 os::init_before_ergo();
3764
3765 jint ergo_result = Arguments::apply_ergo();
3766 if (ergo_result != JNI_OK) return ergo_result;
3767
3768 // Final check of all ranges after ergonomics which may change values.
3769 if (!JVMFlagRangeList::check_ranges()) {
3770 return JNI_EINVAL;
3771 }
3772
3773 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3774 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo);
3775 if (!constraint_result) {
3776 return JNI_EINVAL;
3777 }
3778
3779 JVMFlagWriteableList::mark_startup();
3780
3781 if (PauseAtStartup) {
3782 os::pause();
3783 }
3784
3785 HOTSPOT_VM_INIT_BEGIN();
3786
3787 // Timing (must come after argument parsing)
3788 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3789
3790 // Initialize the os module after parsing the args
3791 jint os_init_2_result = os::init_2();
3792 if (os_init_2_result != JNI_OK) return os_init_2_result;
3793
3794 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3795 // Initialize assert poison page mechanism.
3796 if (ShowRegistersOnAssert) {
3797 initialize_assert_poison();
3798 }
3799 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3800
3801 SafepointMechanism::initialize();
3802
3803 jint adjust_after_os_result = Arguments::adjust_after_os();
3804 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3805
3806 // Initialize output stream logging
3807 ostream_init_log();
3808
3809 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3810 // Must be before create_vm_init_agents()
3811 if (Arguments::init_libraries_at_startup()) {
3812 convert_vm_init_libraries_to_agents();
3813 }
3814
3815 // Launch -agentlib/-agentpath and converted -Xrun agents
3816 if (Arguments::init_agents_at_startup()) {
3817 create_vm_init_agents();
3818 }
3819
3820 // Initialize Threads state
3821 _number_of_threads = 0;
3822 _number_of_non_daemon_threads = 0;
3823
3824 // Initialize global data structures and create system classes in heap
3825 vm_init_globals();
3826
3827 #if INCLUDE_JVMCI
3828 if (JVMCICounterSize > 0) {
3829 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
3830 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3831 } else {
3832 JavaThread::_jvmci_old_thread_counters = NULL;
3833 }
3834 #endif // INCLUDE_JVMCI
3835
3836 // Attach the main thread to this os thread
3837 JavaThread* main_thread = new JavaThread();
3838 main_thread->set_thread_state(_thread_in_vm);
3839 main_thread->initialize_thread_current();
3840 // must do this before set_active_handles
3841 main_thread->record_stack_base_and_size();
3842 main_thread->register_thread_stack_with_NMT();
3843 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3844
3845 if (!main_thread->set_as_starting_thread()) {
3846 vm_shutdown_during_initialization(
3847 "Failed necessary internal allocation. Out of swap space");
3848 main_thread->smr_delete();
3849 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3850 return JNI_ENOMEM;
3851 }
3852
3853 // Enable guard page *after* os::create_main_thread(), otherwise it would
3854 // crash Linux VM, see notes in os_linux.cpp.
3855 main_thread->create_stack_guard_pages();
3856
3857 // Initialize Java-Level synchronization subsystem
3858 ObjectMonitor::Initialize();
3859
3860 // Initialize global modules
3861 jint status = init_globals();
3862 if (status != JNI_OK) {
3863 main_thread->smr_delete();
3864 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3865 return status;
3866 }
3867
3868 JFR_ONLY(Jfr::on_vm_init();)
3869
3870 // Should be done after the heap is fully created
3871 main_thread->cache_global_variables();
3872
3873 HandleMark hm;
3874
3875 { MutexLocker mu(Threads_lock);
3876 Threads::add(main_thread);
3877 }
3878
3879 // Any JVMTI raw monitors entered in onload will transition into
3880 // real raw monitor. VM is setup enough here for raw monitor enter.
3881 JvmtiExport::transition_pending_onload_raw_monitors();
3882
3883 // Create the VMThread
3884 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3885
3886 VMThread::create();
3887 Thread* vmthread = VMThread::vm_thread();
3888
3889 if (!os::create_thread(vmthread, os::vm_thread)) {
3890 vm_exit_during_initialization("Cannot create VM thread. "
3891 "Out of system resources.");
3892 }
3893
3894 // Wait for the VM thread to become ready, and VMThread::run to initialize
3895 // Monitors can have spurious returns, must always check another state flag
3896 {
3897 MonitorLocker ml(Notify_lock);
3898 os::start_thread(vmthread);
3899 while (vmthread->active_handles() == NULL) {
3900 ml.wait();
3901 }
3902 }
3903 }
3904
3905 assert(Universe::is_fully_initialized(), "not initialized");
3906 if (VerifyDuringStartup) {
3907 // Make sure we're starting with a clean slate.
3908 VM_Verify verify_op;
3909 VMThread::execute(&verify_op);
3910 }
3911
3912 // We need this to update the java.vm.info property in case any flags used
3913 // to initially define it have been changed. This is needed for both CDS and
3914 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info
3915 // is initially computed. See Abstract_VM_Version::vm_info_string().
3916 // This update must happen before we initialize the java classes, but
3917 // after any initialization logic that might modify the flags.
3918 Arguments::update_vm_info_property(VM_Version::vm_info_string());
3919
3920 Thread* THREAD = Thread::current();
3921
3922 // Always call even when there are not JVMTI environments yet, since environments
3923 // may be attached late and JVMTI must track phases of VM execution
3924 JvmtiExport::enter_early_start_phase();
3925
3926 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3927 JvmtiExport::post_early_vm_start();
3928
3929 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3930
3931 quicken_jni_functions();
3932
3933 // No more stub generation allowed after that point.
3934 StubCodeDesc::freeze();
3935
3936 // Set flag that basic initialization has completed. Used by exceptions and various
3937 // debug stuff, that does not work until all basic classes have been initialized.
3938 set_init_completed();
3939
3940 LogConfiguration::post_initialize();
3941 Metaspace::post_initialize();
3942
3943 HOTSPOT_VM_INIT_END();
3944
3945 // record VM initialization completion time
3946 #if INCLUDE_MANAGEMENT
3947 Management::record_vm_init_completed();
3948 #endif // INCLUDE_MANAGEMENT
3949
3950 // Signal Dispatcher needs to be started before VMInit event is posted
3951 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3952
3953 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3954 if (!DisableAttachMechanism) {
3955 AttachListener::vm_start();
3956 if (StartAttachListener || AttachListener::init_at_startup()) {
3957 AttachListener::init();
3958 }
3959 }
3960
3961 // Launch -Xrun agents
3962 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3963 // back-end can launch with -Xdebug -Xrunjdwp.
3964 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3965 create_vm_init_libraries();
3966 }
3967
3968 if (CleanChunkPoolAsync) {
3969 Chunk::start_chunk_pool_cleaner_task();
3970 }
3971
3972
3973 // initialize compiler(s)
3974 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3975 #if INCLUDE_JVMCI
3976 bool force_JVMCI_intialization = false;
3977 if (EnableJVMCI) {
3978 // Initialize JVMCI eagerly when it is explicitly requested.
3979 // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
3980 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
3981
3982 if (!force_JVMCI_intialization) {
3983 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3984 // compilations via JVMCI will not actually block until JVMCI is initialized.
3985 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3986 }
3987 }
3988 #endif
3989 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
3990 // Postpone completion of compiler initialization to after JVMCI
3991 // is initialized to avoid timeouts of blocking compilations.
3992 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
3993 CompileBroker::compilation_init_phase2();
3994 }
3995 #endif
3996
3997 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3998 // It is done after compilers are initialized, because otherwise compilations of
3999 // signature polymorphic MH intrinsics can be missed
4000 // (see SystemDictionary::find_method_handle_intrinsic).
4001 initialize_jsr292_core_classes(CHECK_JNI_ERR);
4002
4003 // This will initialize the module system. Only java.base classes can be
4004 // loaded until phase 2 completes
4005 call_initPhase2(CHECK_JNI_ERR);
4006
4007 // Always call even when there are not JVMTI environments yet, since environments
4008 // may be attached late and JVMTI must track phases of VM execution
4009 JvmtiExport::enter_start_phase();
4010
4011 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
4012 JvmtiExport::post_vm_start();
4013
4014 // Final system initialization including security manager and system class loader
4015 call_initPhase3(CHECK_JNI_ERR);
4016
4017 // cache the system and platform class loaders
4018 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
4019
4020 #if INCLUDE_CDS
4021 // capture the module path info from the ModuleEntryTable
4022 ClassLoader::initialize_module_path(THREAD);
4023 #endif
4024
4025 #if INCLUDE_JVMCI
4026 if (force_JVMCI_intialization) {
4027 JVMCI::initialize_compiler(CHECK_JNI_ERR);
4028 CompileBroker::compilation_init_phase2();
4029 }
4030 #endif
4031
4032 // Always call even when there are not JVMTI environments yet, since environments
4033 // may be attached late and JVMTI must track phases of VM execution
4034 JvmtiExport::enter_live_phase();
4035
4036 // Make perfmemory accessible
4037 PerfMemory::set_accessible(true);
4038
4039 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
4040 JvmtiExport::post_vm_initialized();
4041
4042 JFR_ONLY(Jfr::on_vm_start();)
4043
4044 #if INCLUDE_MANAGEMENT
4045 Management::initialize(THREAD);
4046
4047 if (HAS_PENDING_EXCEPTION) {
4048 // management agent fails to start possibly due to
4049 // configuration problem and is responsible for printing
4050 // stack trace if appropriate. Simply exit VM.
4051 vm_exit(1);
4052 }
4053 #endif // INCLUDE_MANAGEMENT
4054
4055 if (MemProfiling) MemProfiler::engage();
4056 StatSampler::engage();
4057 if (CheckJNICalls) JniPeriodicChecker::engage();
4058
4059 BiasedLocking::init();
4060
4061 #if INCLUDE_RTM_OPT
4062 RTMLockingCounters::init();
4063 #endif
4064
4065 call_postVMInitHook(THREAD);
4066 // The Java side of PostVMInitHook.run must deal with all
4067 // exceptions and provide means of diagnosis.
4068 if (HAS_PENDING_EXCEPTION) {
4069 CLEAR_PENDING_EXCEPTION;
4070 }
4071
4072 {
4073 MutexLocker ml(PeriodicTask_lock);
4074 // Make sure the WatcherThread can be started by WatcherThread::start()
4075 // or by dynamic enrollment.
4076 WatcherThread::make_startable();
4077 // Start up the WatcherThread if there are any periodic tasks
4078 // NOTE: All PeriodicTasks should be registered by now. If they
4079 // aren't, late joiners might appear to start slowly (we might
4080 // take a while to process their first tick).
4081 if (PeriodicTask::num_tasks() > 0) {
4082 WatcherThread::start();
4083 }
4084 }
4085
4086 create_vm_timer.end();
4087 #ifdef ASSERT
4088 _vm_complete = true;
4089 #endif
4090
4091 if (DumpSharedSpaces) {
4092 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
4093 ShouldNotReachHere();
4094 }
4095
4096 return JNI_OK;
4097 }
4098
4099 // type for the Agent_OnLoad and JVM_OnLoad entry points
4100 extern "C" {
4101 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
4102 }
4103 // Find a command line agent library and return its entry point for
4104 // -agentlib: -agentpath: -Xrun
4105 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
4106 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
4107 const char *on_load_symbols[],
4108 size_t num_symbol_entries) {
4109 OnLoadEntry_t on_load_entry = NULL;
4110 void *library = NULL;
4111
4112 if (!agent->valid()) {
4113 char buffer[JVM_MAXPATHLEN];
4114 char ebuf[1024] = "";
4115 const char *name = agent->name();
4116 const char *msg = "Could not find agent library ";
4117
4118 // First check to see if agent is statically linked into executable
4119 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
4120 library = agent->os_lib();
4121 } else if (agent->is_absolute_path()) {
4122 library = os::dll_load(name, ebuf, sizeof ebuf);
4123 if (library == NULL) {
4124 const char *sub_msg = " in absolute path, with error: ";
4125 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4126 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4127 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4128 // If we can't find the agent, exit.
4129 vm_exit_during_initialization(buf, NULL);
4130 FREE_C_HEAP_ARRAY(char, buf);
4131 }
4132 } else {
4133 // Try to load the agent from the standard dll directory
4134 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4135 name)) {
4136 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4137 }
4138 if (library == NULL) { // Try the library path directory.
4139 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4140 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4141 }
4142 if (library == NULL) {
4143 const char *sub_msg = " on the library path, with error: ";
4144 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4145
4146 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4147 strlen(ebuf) + strlen(sub_msg2) + 1;
4148 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4149 if (!agent->is_instrument_lib()) {
4150 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4151 } else {
4152 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4153 }
4154 // If we can't find the agent, exit.
4155 vm_exit_during_initialization(buf, NULL);
4156 FREE_C_HEAP_ARRAY(char, buf);
4157 }
4158 }
4159 }
4160 agent->set_os_lib(library);
4161 agent->set_valid();
4162 }
4163
4164 // Find the OnLoad function.
4165 on_load_entry =
4166 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4167 false,
4168 on_load_symbols,
4169 num_symbol_entries));
4170 return on_load_entry;
4171 }
4172
4173 // Find the JVM_OnLoad entry point
4174 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4175 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4176 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4177 }
4178
4179 // Find the Agent_OnLoad entry point
4180 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4181 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4182 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4183 }
4184
4185 // For backwards compatibility with -Xrun
4186 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4187 // treated like -agentpath:
4188 // Must be called before agent libraries are created
4189 void Threads::convert_vm_init_libraries_to_agents() {
4190 AgentLibrary* agent;
4191 AgentLibrary* next;
4192
4193 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4194 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4195 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4196
4197 // If there is an JVM_OnLoad function it will get called later,
4198 // otherwise see if there is an Agent_OnLoad
4199 if (on_load_entry == NULL) {
4200 on_load_entry = lookup_agent_on_load(agent);
4201 if (on_load_entry != NULL) {
4202 // switch it to the agent list -- so that Agent_OnLoad will be called,
4203 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4204 Arguments::convert_library_to_agent(agent);
4205 } else {
4206 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4207 }
4208 }
4209 }
4210 }
4211
4212 // Create agents for -agentlib: -agentpath: and converted -Xrun
4213 // Invokes Agent_OnLoad
4214 // Called very early -- before JavaThreads exist
4215 void Threads::create_vm_init_agents() {
4216 extern struct JavaVM_ main_vm;
4217 AgentLibrary* agent;
4218
4219 JvmtiExport::enter_onload_phase();
4220
4221 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4222 // CDS dumping does not support native JVMTI agent.
4223 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
4224 if (DumpSharedSpaces || DynamicDumpSharedSpaces) {
4225 if(!agent->is_instrument_lib()) {
4226 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
4227 } else if (!AllowArchivingWithJavaAgent) {
4228 vm_exit_during_cds_dumping(
4229 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
4230 }
4231 }
4232
4233 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4234
4235 if (on_load_entry != NULL) {
4236 // Invoke the Agent_OnLoad function
4237 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4238 if (err != JNI_OK) {
4239 vm_exit_during_initialization("agent library failed to init", agent->name());
4240 }
4241 } else {
4242 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4243 }
4244 }
4245
4246 JvmtiExport::enter_primordial_phase();
4247 }
4248
4249 extern "C" {
4250 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4251 }
4252
4253 void Threads::shutdown_vm_agents() {
4254 // Send any Agent_OnUnload notifications
4255 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4256 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4257 extern struct JavaVM_ main_vm;
4258 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4259
4260 // Find the Agent_OnUnload function.
4261 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4262 os::find_agent_function(agent,
4263 false,
4264 on_unload_symbols,
4265 num_symbol_entries));
4266
4267 // Invoke the Agent_OnUnload function
4268 if (unload_entry != NULL) {
4269 JavaThread* thread = JavaThread::current();
4270 ThreadToNativeFromVM ttn(thread);
4271 HandleMark hm(thread);
4272 (*unload_entry)(&main_vm);
4273 }
4274 }
4275 }
4276
4277 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4278 // Invokes JVM_OnLoad
4279 void Threads::create_vm_init_libraries() {
4280 extern struct JavaVM_ main_vm;
4281 AgentLibrary* agent;
4282
4283 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4284 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4285
4286 if (on_load_entry != NULL) {
4287 // Invoke the JVM_OnLoad function
4288 JavaThread* thread = JavaThread::current();
4289 ThreadToNativeFromVM ttn(thread);
4290 HandleMark hm(thread);
4291 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4292 if (err != JNI_OK) {
4293 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4294 }
4295 } else {
4296 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4297 }
4298 }
4299 }
4300
4301
4302 // Last thread running calls java.lang.Shutdown.shutdown()
4303 void JavaThread::invoke_shutdown_hooks() {
4304 HandleMark hm(this);
4305
4306 // We could get here with a pending exception, if so clear it now.
4307 if (this->has_pending_exception()) {
4308 this->clear_pending_exception();
4309 }
4310
4311 EXCEPTION_MARK;
4312 Klass* shutdown_klass =
4313 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4314 THREAD);
4315 if (shutdown_klass != NULL) {
4316 // SystemDictionary::resolve_or_null will return null if there was
4317 // an exception. If we cannot load the Shutdown class, just don't
4318 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4319 // won't be run. Note that if a shutdown hook was registered,
4320 // the Shutdown class would have already been loaded
4321 // (Runtime.addShutdownHook will load it).
4322 JavaValue result(T_VOID);
4323 JavaCalls::call_static(&result,
4324 shutdown_klass,
4325 vmSymbols::shutdown_name(),
4326 vmSymbols::void_method_signature(),
4327 THREAD);
4328 }
4329 CLEAR_PENDING_EXCEPTION;
4330 }
4331
4332 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4333 // the program falls off the end of main(). Another VM exit path is through
4334 // vm_exit() when the program calls System.exit() to return a value or when
4335 // there is a serious error in VM. The two shutdown paths are not exactly
4336 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4337 // and VM_Exit op at VM level.
4338 //
4339 // Shutdown sequence:
4340 // + Shutdown native memory tracking if it is on
4341 // + Wait until we are the last non-daemon thread to execute
4342 // <-- every thing is still working at this moment -->
4343 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4344 // shutdown hooks
4345 // + Call before_exit(), prepare for VM exit
4346 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4347 // currently the only user of this mechanism is File.deleteOnExit())
4348 // > stop StatSampler, watcher thread, CMS threads,
4349 // post thread end and vm death events to JVMTI,
4350 // stop signal thread
4351 // + Call JavaThread::exit(), it will:
4352 // > release JNI handle blocks, remove stack guard pages
4353 // > remove this thread from Threads list
4354 // <-- no more Java code from this thread after this point -->
4355 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4356 // the compiler threads at safepoint
4357 // <-- do not use anything that could get blocked by Safepoint -->
4358 // + Disable tracing at JNI/JVM barriers
4359 // + Set _vm_exited flag for threads that are still running native code
4360 // + Call exit_globals()
4361 // > deletes tty
4362 // > deletes PerfMemory resources
4363 // + Delete this thread
4364 // + Return to caller
4365
4366 bool Threads::destroy_vm() {
4367 JavaThread* thread = JavaThread::current();
4368
4369 #ifdef ASSERT
4370 _vm_complete = false;
4371 #endif
4372 // Wait until we are the last non-daemon thread to execute
4373 { MonitorLocker nu(Threads_lock);
4374 while (Threads::number_of_non_daemon_threads() > 1)
4375 // This wait should make safepoint checks, wait without a timeout,
4376 // and wait as a suspend-equivalent condition.
4377 nu.wait(0, Mutex::_as_suspend_equivalent_flag);
4378 }
4379
4380 EventShutdown e;
4381 if (e.should_commit()) {
4382 e.set_reason("No remaining non-daemon Java threads");
4383 e.commit();
4384 }
4385
4386 // Hang forever on exit if we are reporting an error.
4387 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4388 os::infinite_sleep();
4389 }
4390 os::wait_for_keypress_at_exit();
4391
4392 // run Java level shutdown hooks
4393 thread->invoke_shutdown_hooks();
4394
4395 before_exit(thread);
4396
4397 thread->exit(true);
4398
4399 // Stop VM thread.
4400 {
4401 // 4945125 The vm thread comes to a safepoint during exit.
4402 // GC vm_operations can get caught at the safepoint, and the
4403 // heap is unparseable if they are caught. Grab the Heap_lock
4404 // to prevent this. The GC vm_operations will not be able to
4405 // queue until after the vm thread is dead. After this point,
4406 // we'll never emerge out of the safepoint before the VM exits.
4407
4408 MutexLocker ml(Heap_lock, Mutex::_no_safepoint_check_flag);
4409
4410 VMThread::wait_for_vm_thread_exit();
4411 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4412 VMThread::destroy();
4413 }
4414
4415 // Now, all Java threads are gone except daemon threads. Daemon threads
4416 // running Java code or in VM are stopped by the Safepoint. However,
4417 // daemon threads executing native code are still running. But they
4418 // will be stopped at native=>Java/VM barriers. Note that we can't
4419 // simply kill or suspend them, as it is inherently deadlock-prone.
4420
4421 VM_Exit::set_vm_exited();
4422
4423 // Clean up ideal graph printers after the VMThread has started
4424 // the final safepoint which will block all the Compiler threads.
4425 // Note that this Thread has already logically exited so the
4426 // clean_up() function's use of a JavaThreadIteratorWithHandle
4427 // would be a problem except set_vm_exited() has remembered the
4428 // shutdown thread which is granted a policy exception.
4429 #if defined(COMPILER2) && !defined(PRODUCT)
4430 IdealGraphPrinter::clean_up();
4431 #endif
4432
4433 notify_vm_shutdown();
4434
4435 // exit_globals() will delete tty
4436 exit_globals();
4437
4438 // We are after VM_Exit::set_vm_exited() so we can't call
4439 // thread->smr_delete() or we will block on the Threads_lock.
4440 // Deleting the shutdown thread here is safe because another
4441 // JavaThread cannot have an active ThreadsListHandle for
4442 // this JavaThread.
4443 delete thread;
4444
4445 #if INCLUDE_JVMCI
4446 if (JVMCICounterSize > 0) {
4447 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4448 }
4449 #endif
4450
4451 LogConfiguration::finalize();
4452
4453 return true;
4454 }
4455
4456
4457 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4458 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4459 return is_supported_jni_version(version);
4460 }
4461
4462
4463 jboolean Threads::is_supported_jni_version(jint version) {
4464 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4465 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4466 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4467 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4468 if (version == JNI_VERSION_9) return JNI_TRUE;
4469 if (version == JNI_VERSION_10) return JNI_TRUE;
4470 return JNI_FALSE;
4471 }
4472
4473
4474 void Threads::add(JavaThread* p, bool force_daemon) {
4475 // The threads lock must be owned at this point
4476 assert(Threads_lock->owned_by_self(), "must have threads lock");
4477
4478 BarrierSet::barrier_set()->on_thread_attach(p);
4479
4480 // Once a JavaThread is added to the Threads list, smr_delete() has
4481 // to be used to delete it. Otherwise we can just delete it directly.
4482 p->set_on_thread_list();
4483
4484 _number_of_threads++;
4485 oop threadObj = p->threadObj();
4486 bool daemon = true;
4487 // Bootstrapping problem: threadObj can be null for initial
4488 // JavaThread (or for threads attached via JNI)
4489 if ((!force_daemon) && !is_daemon((threadObj))) {
4490 _number_of_non_daemon_threads++;
4491 daemon = false;
4492 }
4493
4494 ThreadService::add_thread(p, daemon);
4495
4496 // Maintain fast thread list
4497 ThreadsSMRSupport::add_thread(p);
4498
4499 // Possible GC point.
4500 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4501 }
4502
4503 void Threads::remove(JavaThread* p, bool is_daemon) {
4504
4505 // Reclaim the ObjectMonitors from the omInUseList and omFreeList of the moribund thread.
4506 ObjectSynchronizer::omFlush(p);
4507
4508 // Extra scope needed for Thread_lock, so we can check
4509 // that we do not remove thread without safepoint code notice
4510 { MonitorLocker ml(Threads_lock);
4511
4512 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4513
4514 // Maintain fast thread list
4515 ThreadsSMRSupport::remove_thread(p);
4516
4517 _number_of_threads--;
4518 if (!is_daemon) {
4519 _number_of_non_daemon_threads--;
4520
4521 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4522 // on destroy_vm will wake up.
4523 if (number_of_non_daemon_threads() == 1) {
4524 ml.notify_all();
4525 }
4526 }
4527 ThreadService::remove_thread(p, is_daemon);
4528
4529 // Make sure that safepoint code disregard this thread. This is needed since
4530 // the thread might mess around with locks after this point. This can cause it
4531 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4532 // of this thread since it is removed from the queue.
4533 p->set_terminated_value();
4534 } // unlock Threads_lock
4535
4536 // Since Events::log uses a lock, we grab it outside the Threads_lock
4537 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4538 }
4539
4540 // Operations on the Threads list for GC. These are not explicitly locked,
4541 // but the garbage collector must provide a safe context for them to run.
4542 // In particular, these things should never be called when the Threads_lock
4543 // is held by some other thread. (Note: the Safepoint abstraction also
4544 // uses the Threads_lock to guarantee this property. It also makes sure that
4545 // all threads gets blocked when exiting or starting).
4546
4547 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4548 ALL_JAVA_THREADS(p) {
4549 p->oops_do(f, cf);
4550 }
4551 VMThread::vm_thread()->oops_do(f, cf);
4552 }
4553
4554 void Threads::change_thread_claim_token() {
4555 if (++_thread_claim_token == 0) {
4556 // On overflow of the token counter, there is a risk of future
4557 // collisions between a new global token value and a stale token
4558 // for a thread, because not all iterations visit all threads.
4559 // (Though it's pretty much a theoretical concern for non-trivial
4560 // token counter sizes.) To deal with the possibility, reset all
4561 // the thread tokens to zero on global token overflow.
4562 struct ResetClaims : public ThreadClosure {
4563 virtual void do_thread(Thread* t) {
4564 t->claim_threads_do(false, 0);
4565 }
4566 } reset_claims;
4567 Threads::threads_do(&reset_claims);
4568 // On overflow, update the global token to non-zero, to
4569 // avoid the special "never claimed" initial thread value.
4570 _thread_claim_token = 1;
4571 }
4572 }
4573
4574 #ifdef ASSERT
4575 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
4576 const uintx token = t->threads_do_token();
4577 assert(token == expected,
4578 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
4579 UINTX_FORMAT, kind, p2i(t), token, expected);
4580 }
4581
4582 void Threads::assert_all_threads_claimed() {
4583 ALL_JAVA_THREADS(p) {
4584 assert_thread_claimed("Thread", p, _thread_claim_token);
4585 }
4586 assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token);
4587 }
4588 #endif // ASSERT
4589
4590 class ParallelOopsDoThreadClosure : public ThreadClosure {
4591 private:
4592 OopClosure* _f;
4593 CodeBlobClosure* _cf;
4594 public:
4595 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4596 void do_thread(Thread* t) {
4597 t->oops_do(_f, _cf);
4598 }
4599 };
4600
4601 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4602 ParallelOopsDoThreadClosure tc(f, cf);
4603 possibly_parallel_threads_do(is_par, &tc);
4604 }
4605
4606 void Threads::nmethods_do(CodeBlobClosure* cf) {
4607 ALL_JAVA_THREADS(p) {
4608 // This is used by the code cache sweeper to mark nmethods that are active
4609 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4610 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4611 if(!p->is_Code_cache_sweeper_thread()) {
4612 p->nmethods_do(cf);
4613 }
4614 }
4615 }
4616
4617 void Threads::metadata_do(MetadataClosure* f) {
4618 ALL_JAVA_THREADS(p) {
4619 p->metadata_do(f);
4620 }
4621 }
4622
4623 class ThreadHandlesClosure : public ThreadClosure {
4624 void (*_f)(Metadata*);
4625 public:
4626 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4627 virtual void do_thread(Thread* thread) {
4628 thread->metadata_handles_do(_f);
4629 }
4630 };
4631
4632 void Threads::metadata_handles_do(void f(Metadata*)) {
4633 // Only walk the Handles in Thread.
4634 ThreadHandlesClosure handles_closure(f);
4635 threads_do(&handles_closure);
4636 }
4637
4638 void Threads::deoptimized_wrt_marked_nmethods() {
4639 ALL_JAVA_THREADS(p) {
4640 p->deoptimized_wrt_marked_nmethods();
4641 }
4642 }
4643
4644
4645 // Get count Java threads that are waiting to enter the specified monitor.
4646 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4647 int count,
4648 address monitor) {
4649 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4650
4651 int i = 0;
4652 DO_JAVA_THREADS(t_list, p) {
4653 if (!p->can_call_java()) continue;
4654
4655 address pending = (address)p->current_pending_monitor();
4656 if (pending == monitor) { // found a match
4657 if (i < count) result->append(p); // save the first count matches
4658 i++;
4659 }
4660 }
4661
4662 return result;
4663 }
4664
4665
4666 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4667 address owner) {
4668 // NULL owner means not locked so we can skip the search
4669 if (owner == NULL) return NULL;
4670
4671 DO_JAVA_THREADS(t_list, p) {
4672 // first, see if owner is the address of a Java thread
4673 if (owner == (address)p) return p;
4674 }
4675
4676 // Cannot assert on lack of success here since this function may be
4677 // used by code that is trying to report useful problem information
4678 // like deadlock detection.
4679 if (UseHeavyMonitors) return NULL;
4680
4681 // If we didn't find a matching Java thread and we didn't force use of
4682 // heavyweight monitors, then the owner is the stack address of the
4683 // Lock Word in the owning Java thread's stack.
4684 //
4685 JavaThread* the_owner = NULL;
4686 DO_JAVA_THREADS(t_list, q) {
4687 if (q->is_lock_owned(owner)) {
4688 the_owner = q;
4689 break;
4690 }
4691 }
4692
4693 // cannot assert on lack of success here; see above comment
4694 return the_owner;
4695 }
4696
4697 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4698 void Threads::print_on(outputStream* st, bool print_stacks,
4699 bool internal_format, bool print_concurrent_locks,
4700 bool print_extended_info) {
4701 char buf[32];
4702 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4703
4704 st->print_cr("Full thread dump %s (%s %s):",
4705 VM_Version::vm_name(),
4706 VM_Version::vm_release(),
4707 VM_Version::vm_info_string());
4708 st->cr();
4709
4710 #if INCLUDE_SERVICES
4711 // Dump concurrent locks
4712 ConcurrentLocksDump concurrent_locks;
4713 if (print_concurrent_locks) {
4714 concurrent_locks.dump_at_safepoint();
4715 }
4716 #endif // INCLUDE_SERVICES
4717
4718 ThreadsSMRSupport::print_info_on(st);
4719 st->cr();
4720
4721 ALL_JAVA_THREADS(p) {
4722 ResourceMark rm;
4723 p->print_on(st, print_extended_info);
4724 if (print_stacks) {
4725 if (internal_format) {
4726 p->trace_stack();
4727 } else {
4728 p->print_stack_on(st);
4729 }
4730 }
4731 st->cr();
4732 #if INCLUDE_SERVICES
4733 if (print_concurrent_locks) {
4734 concurrent_locks.print_locks_on(p, st);
4735 }
4736 #endif // INCLUDE_SERVICES
4737 }
4738
4739 VMThread::vm_thread()->print_on(st);
4740 st->cr();
4741 Universe::heap()->print_gc_threads_on(st);
4742 WatcherThread* wt = WatcherThread::watcher_thread();
4743 if (wt != NULL) {
4744 wt->print_on(st);
4745 st->cr();
4746 }
4747
4748 st->flush();
4749 }
4750
4751 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4752 int buflen, bool* found_current) {
4753 if (this_thread != NULL) {
4754 bool is_current = (current == this_thread);
4755 *found_current = *found_current || is_current;
4756 st->print("%s", is_current ? "=>" : " ");
4757
4758 st->print(PTR_FORMAT, p2i(this_thread));
4759 st->print(" ");
4760 this_thread->print_on_error(st, buf, buflen);
4761 st->cr();
4762 }
4763 }
4764
4765 class PrintOnErrorClosure : public ThreadClosure {
4766 outputStream* _st;
4767 Thread* _current;
4768 char* _buf;
4769 int _buflen;
4770 bool* _found_current;
4771 public:
4772 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4773 int buflen, bool* found_current) :
4774 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4775
4776 virtual void do_thread(Thread* thread) {
4777 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4778 }
4779 };
4780
4781 // Threads::print_on_error() is called by fatal error handler. It's possible
4782 // that VM is not at safepoint and/or current thread is inside signal handler.
4783 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4784 // memory (even in resource area), it might deadlock the error handler.
4785 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4786 int buflen) {
4787 ThreadsSMRSupport::print_info_on(st);
4788 st->cr();
4789
4790 bool found_current = false;
4791 st->print_cr("Java Threads: ( => current thread )");
4792 ALL_JAVA_THREADS(thread) {
4793 print_on_error(thread, st, current, buf, buflen, &found_current);
4794 }
4795 st->cr();
4796
4797 st->print_cr("Other Threads:");
4798 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4799 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4800
4801 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4802 Universe::heap()->gc_threads_do(&print_closure);
4803
4804 if (!found_current) {
4805 st->cr();
4806 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4807 current->print_on_error(st, buf, buflen);
4808 st->cr();
4809 }
4810 st->cr();
4811
4812 st->print_cr("Threads with active compile tasks:");
4813 print_threads_compiling(st, buf, buflen);
4814 }
4815
4816 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
4817 ALL_JAVA_THREADS(thread) {
4818 if (thread->is_Compiler_thread()) {
4819 CompilerThread* ct = (CompilerThread*) thread;
4820
4821 // Keep task in local variable for NULL check.
4822 // ct->_task might be set to NULL by concurring compiler thread
4823 // because it completed the compilation. The task is never freed,
4824 // though, just returned to a free list.
4825 CompileTask* task = ct->task();
4826 if (task != NULL) {
4827 thread->print_name_on_error(st, buf, buflen);
4828 st->print(" ");
4829 task->print(st, NULL, short_form, true);
4830 }
4831 }
4832 }
4833 }
4834
4835
4836 // Internal SpinLock and Mutex
4837 // Based on ParkEvent
4838
4839 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4840 //
4841 // We employ SpinLocks _only for low-contention, fixed-length
4842 // short-duration critical sections where we're concerned
4843 // about native mutex_t or HotSpot Mutex:: latency.
4844 // The mux construct provides a spin-then-block mutual exclusion
4845 // mechanism.
4846 //
4847 // Testing has shown that contention on the ListLock guarding gFreeList
4848 // is common. If we implement ListLock as a simple SpinLock it's common
4849 // for the JVM to devolve to yielding with little progress. This is true
4850 // despite the fact that the critical sections protected by ListLock are
4851 // extremely short.
4852 //
4853 // TODO-FIXME: ListLock should be of type SpinLock.
4854 // We should make this a 1st-class type, integrated into the lock
4855 // hierarchy as leaf-locks. Critically, the SpinLock structure
4856 // should have sufficient padding to avoid false-sharing and excessive
4857 // cache-coherency traffic.
4858
4859
4860 typedef volatile int SpinLockT;
4861
4862 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4863 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4864 return; // normal fast-path return
4865 }
4866
4867 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4868 int ctr = 0;
4869 int Yields = 0;
4870 for (;;) {
4871 while (*adr != 0) {
4872 ++ctr;
4873 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4874 if (Yields > 5) {
4875 os::naked_short_sleep(1);
4876 } else {
4877 os::naked_yield();
4878 ++Yields;
4879 }
4880 } else {
4881 SpinPause();
4882 }
4883 }
4884 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4885 }
4886 }
4887
4888 void Thread::SpinRelease(volatile int * adr) {
4889 assert(*adr != 0, "invariant");
4890 OrderAccess::fence(); // guarantee at least release consistency.
4891 // Roach-motel semantics.
4892 // It's safe if subsequent LDs and STs float "up" into the critical section,
4893 // but prior LDs and STs within the critical section can't be allowed
4894 // to reorder or float past the ST that releases the lock.
4895 // Loads and stores in the critical section - which appear in program
4896 // order before the store that releases the lock - must also appear
4897 // before the store that releases the lock in memory visibility order.
4898 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4899 // the ST of 0 into the lock-word which releases the lock, so fence
4900 // more than covers this on all platforms.
4901 *adr = 0;
4902 }
4903
4904 // muxAcquire and muxRelease:
4905 //
4906 // * muxAcquire and muxRelease support a single-word lock-word construct.
4907 // The LSB of the word is set IFF the lock is held.
4908 // The remainder of the word points to the head of a singly-linked list
4909 // of threads blocked on the lock.
4910 //
4911 // * The current implementation of muxAcquire-muxRelease uses its own
4912 // dedicated Thread._MuxEvent instance. If we're interested in
4913 // minimizing the peak number of extant ParkEvent instances then
4914 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4915 // as certain invariants were satisfied. Specifically, care would need
4916 // to be taken with regards to consuming unpark() "permits".
4917 // A safe rule of thumb is that a thread would never call muxAcquire()
4918 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4919 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4920 // consume an unpark() permit intended for monitorenter, for instance.
4921 // One way around this would be to widen the restricted-range semaphore
4922 // implemented in park(). Another alternative would be to provide
4923 // multiple instances of the PlatformEvent() for each thread. One
4924 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4925 //
4926 // * Usage:
4927 // -- Only as leaf locks
4928 // -- for short-term locking only as muxAcquire does not perform
4929 // thread state transitions.
4930 //
4931 // Alternatives:
4932 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4933 // but with parking or spin-then-park instead of pure spinning.
4934 // * Use Taura-Oyama-Yonenzawa locks.
4935 // * It's possible to construct a 1-0 lock if we encode the lockword as
4936 // (List,LockByte). Acquire will CAS the full lockword while Release
4937 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4938 // acquiring threads use timers (ParkTimed) to detect and recover from
4939 // the stranding window. Thread/Node structures must be aligned on 256-byte
4940 // boundaries by using placement-new.
4941 // * Augment MCS with advisory back-link fields maintained with CAS().
4942 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4943 // The validity of the backlinks must be ratified before we trust the value.
4944 // If the backlinks are invalid the exiting thread must back-track through the
4945 // the forward links, which are always trustworthy.
4946 // * Add a successor indication. The LockWord is currently encoded as
4947 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4948 // to provide the usual futile-wakeup optimization.
4949 // See RTStt for details.
4950 //
4951
4952
4953 const intptr_t LOCKBIT = 1;
4954
4955 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4956 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4957 if (w == 0) return;
4958 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4959 return;
4960 }
4961
4962 ParkEvent * const Self = Thread::current()->_MuxEvent;
4963 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4964 for (;;) {
4965 int its = (os::is_MP() ? 100 : 0) + 1;
4966
4967 // Optional spin phase: spin-then-park strategy
4968 while (--its >= 0) {
4969 w = *Lock;
4970 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4971 return;
4972 }
4973 }
4974
4975 Self->reset();
4976 Self->OnList = intptr_t(Lock);
4977 // The following fence() isn't _strictly necessary as the subsequent
4978 // CAS() both serializes execution and ratifies the fetched *Lock value.
4979 OrderAccess::fence();
4980 for (;;) {
4981 w = *Lock;
4982 if ((w & LOCKBIT) == 0) {
4983 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4984 Self->OnList = 0; // hygiene - allows stronger asserts
4985 return;
4986 }
4987 continue; // Interference -- *Lock changed -- Just retry
4988 }
4989 assert(w & LOCKBIT, "invariant");
4990 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4991 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4992 }
4993
4994 while (Self->OnList != 0) {
4995 Self->park();
4996 }
4997 }
4998 }
4999
5000 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
5001 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
5002 if (w == 0) return;
5003 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
5004 return;
5005 }
5006
5007 ParkEvent * ReleaseAfter = NULL;
5008 if (ev == NULL) {
5009 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
5010 }
5011 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
5012 for (;;) {
5013 guarantee(ev->OnList == 0, "invariant");
5014 int its = (os::is_MP() ? 100 : 0) + 1;
5015
5016 // Optional spin phase: spin-then-park strategy
5017 while (--its >= 0) {
5018 w = *Lock;
5019 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
5020 if (ReleaseAfter != NULL) {
5021 ParkEvent::Release(ReleaseAfter);
5022 }
5023 return;
5024 }
5025 }
5026
5027 ev->reset();
5028 ev->OnList = intptr_t(Lock);
5029 // The following fence() isn't _strictly necessary as the subsequent
5030 // CAS() both serializes execution and ratifies the fetched *Lock value.
5031 OrderAccess::fence();
5032 for (;;) {
5033 w = *Lock;
5034 if ((w & LOCKBIT) == 0) {
5035 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
5036 ev->OnList = 0;
5037 // We call ::Release while holding the outer lock, thus
5038 // artificially lengthening the critical section.
5039 // Consider deferring the ::Release() until the subsequent unlock(),
5040 // after we've dropped the outer lock.
5041 if (ReleaseAfter != NULL) {
5042 ParkEvent::Release(ReleaseAfter);
5043 }
5044 return;
5045 }
5046 continue; // Interference -- *Lock changed -- Just retry
5047 }
5048 assert(w & LOCKBIT, "invariant");
5049 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
5050 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
5051 }
5052
5053 while (ev->OnList != 0) {
5054 ev->park();
5055 }
5056 }
5057 }
5058
5059 // Release() must extract a successor from the list and then wake that thread.
5060 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
5061 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
5062 // Release() would :
5063 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
5064 // (B) Extract a successor from the private list "in-hand"
5065 // (C) attempt to CAS() the residual back into *Lock over null.
5066 // If there were any newly arrived threads and the CAS() would fail.
5067 // In that case Release() would detach the RATs, re-merge the list in-hand
5068 // with the RATs and repeat as needed. Alternately, Release() might
5069 // detach and extract a successor, but then pass the residual list to the wakee.
5070 // The wakee would be responsible for reattaching and remerging before it
5071 // competed for the lock.
5072 //
5073 // Both "pop" and DMR are immune from ABA corruption -- there can be
5074 // multiple concurrent pushers, but only one popper or detacher.
5075 // This implementation pops from the head of the list. This is unfair,
5076 // but tends to provide excellent throughput as hot threads remain hot.
5077 // (We wake recently run threads first).
5078 //
5079 // All paths through muxRelease() will execute a CAS.
5080 // Release consistency -- We depend on the CAS in muxRelease() to provide full
5081 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
5082 // executed within the critical section are complete and globally visible before the
5083 // store (CAS) to the lock-word that releases the lock becomes globally visible.
5084 void Thread::muxRelease(volatile intptr_t * Lock) {
5085 for (;;) {
5086 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
5087 assert(w & LOCKBIT, "invariant");
5088 if (w == LOCKBIT) return;
5089 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
5090 assert(List != NULL, "invariant");
5091 assert(List->OnList == intptr_t(Lock), "invariant");
5092 ParkEvent * const nxt = List->ListNext;
5093 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5094
5095 // The following CAS() releases the lock and pops the head element.
5096 // The CAS() also ratifies the previously fetched lock-word value.
5097 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
5098 continue;
5099 }
5100 List->OnList = 0;
5101 OrderAccess::fence();
5102 List->unpark();
5103 return;
5104 }
5105 }
5106
5107
5108 void Threads::verify() {
5109 ALL_JAVA_THREADS(p) {
5110 p->verify();
5111 }
5112 VMThread* thread = VMThread::vm_thread();
5113 if (thread != NULL) thread->verify();
5114 }