1 /*
2 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classLoader.hpp"
29 #include "classfile/javaClasses.hpp"
30 #include "classfile/moduleEntry.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "code/codeCache.hpp"
34 #include "code/scopeDesc.hpp"
35 #include "compiler/compileBroker.hpp"
36 #include "compiler/compileTask.hpp"
37 #include "gc/shared/barrierSet.hpp"
38 #include "gc/shared/gcId.hpp"
39 #include "gc/shared/gcLocker.inline.hpp"
40 #include "gc/shared/workgroup.hpp"
41 #include "interpreter/interpreter.hpp"
42 #include "interpreter/linkResolver.hpp"
43 #include "interpreter/oopMapCache.hpp"
44 #include "jfr/jfrEvents.hpp"
45 #include "jvmtifiles/jvmtiEnv.hpp"
46 #include "logging/log.hpp"
47 #include "logging/logConfiguration.hpp"
48 #include "logging/logStream.hpp"
49 #include "memory/allocation.inline.hpp"
50 #include "memory/metaspaceShared.hpp"
51 #include "memory/oopFactory.hpp"
52 #include "memory/resourceArea.hpp"
53 #include "memory/universe.hpp"
54 #include "oops/access.inline.hpp"
55 #include "oops/instanceKlass.hpp"
56 #include "oops/objArrayOop.hpp"
57 #include "oops/oop.inline.hpp"
58 #include "oops/symbol.hpp"
59 #include "oops/typeArrayOop.inline.hpp"
60 #include "oops/verifyOopClosure.hpp"
61 #include "prims/jvm_misc.hpp"
62 #include "prims/jvmtiExport.hpp"
63 #include "prims/jvmtiThreadState.hpp"
64 #include "runtime/arguments.hpp"
65 #include "runtime/atomic.hpp"
66 #include "runtime/biasedLocking.hpp"
67 #include "runtime/fieldDescriptor.inline.hpp"
68 #include "runtime/flags/jvmFlagConstraintList.hpp"
69 #include "runtime/flags/jvmFlagRangeList.hpp"
70 #include "runtime/flags/jvmFlagWriteableList.hpp"
71 #include "runtime/deoptimization.hpp"
72 #include "runtime/frame.inline.hpp"
73 #include "runtime/handles.inline.hpp"
74 #include "runtime/handshake.hpp"
75 #include "runtime/init.hpp"
76 #include "runtime/interfaceSupport.inline.hpp"
77 #include "runtime/java.hpp"
78 #include "runtime/javaCalls.hpp"
79 #include "runtime/jniHandles.inline.hpp"
80 #include "runtime/jniPeriodicChecker.hpp"
81 #include "runtime/memprofiler.hpp"
82 #include "runtime/mutexLocker.hpp"
83 #include "runtime/objectMonitor.hpp"
84 #include "runtime/orderAccess.hpp"
85 #include "runtime/osThread.hpp"
86 #include "runtime/prefetch.inline.hpp"
87 #include "runtime/safepoint.hpp"
88 #include "runtime/safepointMechanism.inline.hpp"
89 #include "runtime/safepointVerifiers.hpp"
90 #include "runtime/sharedRuntime.hpp"
91 #include "runtime/statSampler.hpp"
92 #include "runtime/stubRoutines.hpp"
93 #include "runtime/sweeper.hpp"
94 #include "runtime/task.hpp"
95 #include "runtime/thread.inline.hpp"
96 #include "runtime/threadCritical.hpp"
97 #include "runtime/threadSMR.inline.hpp"
98 #include "runtime/threadStatisticalInfo.hpp"
99 #include "runtime/timer.hpp"
100 #include "runtime/timerTrace.hpp"
101 #include "runtime/vframe.inline.hpp"
102 #include "runtime/vframeArray.hpp"
103 #include "runtime/vframe_hp.hpp"
104 #include "runtime/vmThread.hpp"
105 #include "runtime/vmOperations.hpp"
106 #include "runtime/vm_version.hpp"
107 #include "services/attachListener.hpp"
108 #include "services/management.hpp"
109 #include "services/memTracker.hpp"
110 #include "services/threadService.hpp"
111 #include "utilities/align.hpp"
112 #include "utilities/copy.hpp"
113 #include "utilities/defaultStream.hpp"
114 #include "utilities/dtrace.hpp"
115 #include "utilities/events.hpp"
116 #include "utilities/macros.hpp"
117 #include "utilities/preserveException.hpp"
118 #include "utilities/singleWriterSynchronizer.hpp"
119 #include "utilities/vmError.hpp"
120 #if INCLUDE_JVMCI
121 #include "jvmci/jvmci.hpp"
122 #include "jvmci/jvmciEnv.hpp"
123 #endif
124 #ifdef COMPILER1
125 #include "c1/c1_Compiler.hpp"
126 #endif
127 #ifdef COMPILER2
128 #include "opto/c2compiler.hpp"
129 #include "opto/idealGraphPrinter.hpp"
130 #endif
131 #if INCLUDE_RTM_OPT
132 #include "runtime/rtmLocking.hpp"
133 #endif
134 #if INCLUDE_JFR
135 #include "jfr/jfr.hpp"
136 #endif
137
138 // Initialization after module runtime initialization
139 void universe_post_module_init(); // must happen after call_initPhase2
140
141 #ifdef DTRACE_ENABLED
142
143 // Only bother with this argument setup if dtrace is available
144
145 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
146 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
147
148 #define DTRACE_THREAD_PROBE(probe, javathread) \
149 { \
150 ResourceMark rm(this); \
151 int len = 0; \
152 const char* name = (javathread)->get_thread_name(); \
153 len = strlen(name); \
154 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
155 (char *) name, len, \
156 java_lang_Thread::thread_id((javathread)->threadObj()), \
157 (uintptr_t) (javathread)->osthread()->thread_id(), \
158 java_lang_Thread::is_daemon((javathread)->threadObj())); \
159 }
160
161 #else // ndef DTRACE_ENABLED
162
163 #define DTRACE_THREAD_PROBE(probe, javathread)
164
165 #endif // ndef DTRACE_ENABLED
166
167 #ifndef USE_LIBRARY_BASED_TLS_ONLY
168 // Current thread is maintained as a thread-local variable
169 THREAD_LOCAL Thread* Thread::_thr_current = NULL;
170 #endif
171
172 // ======= Thread ========
173 // Support for forcing alignment of thread objects for biased locking
174 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
175 if (UseBiasedLocking) {
176 const size_t alignment = markWord::biased_lock_alignment;
177 size_t aligned_size = size + (alignment - sizeof(intptr_t));
178 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
179 : AllocateHeap(aligned_size, flags, CURRENT_PC,
180 AllocFailStrategy::RETURN_NULL);
181 void* aligned_addr = align_up(real_malloc_addr, alignment);
182 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
183 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
184 "JavaThread alignment code overflowed allocated storage");
185 if (aligned_addr != real_malloc_addr) {
186 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
187 p2i(real_malloc_addr),
188 p2i(aligned_addr));
189 }
190 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
191 return aligned_addr;
192 } else {
193 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
194 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
195 }
196 }
197
198 void Thread::operator delete(void* p) {
199 if (UseBiasedLocking) {
200 FreeHeap(((Thread*) p)->_real_malloc_address);
201 } else {
202 FreeHeap(p);
203 }
204 }
205
206 void JavaThread::smr_delete() {
207 if (_on_thread_list) {
208 ThreadsSMRSupport::smr_delete(this);
209 } else {
210 delete this;
211 }
212 }
213
214 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
215 // JavaThread
216
217 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
218
219 Thread::Thread() {
220
221 DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
222
223 // stack and get_thread
224 set_stack_base(NULL);
225 set_stack_size(0);
226 set_lgrp_id(-1);
227 DEBUG_ONLY(clear_suspendible_thread();)
228
229 // allocated data structures
230 set_osthread(NULL);
231 set_resource_area(new (mtThread)ResourceArea());
232 DEBUG_ONLY(_current_resource_mark = NULL;)
233 set_handle_area(new (mtThread) HandleArea(NULL));
234 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
235 set_active_handles(NULL);
236 set_free_handle_block(NULL);
237 set_last_handle_mark(NULL);
238 DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
239
240 // Initial value of zero ==> never claimed.
241 _threads_do_token = 0;
242 _threads_hazard_ptr = NULL;
243 _threads_list_ptr = NULL;
244 _nested_threads_hazard_ptr_cnt = 0;
245 _rcu_counter = 0;
246
247 // the handle mark links itself to last_handle_mark
248 new HandleMark(this);
249
250 // plain initialization
251 debug_only(_owned_locks = NULL;)
252 NOT_PRODUCT(_no_safepoint_count = 0;)
253 NOT_PRODUCT(_skip_gcalot = false;)
254 _jvmti_env_iteration_count = 0;
255 set_allocated_bytes(0);
256 _vm_operation_started_count = 0;
257 _vm_operation_completed_count = 0;
258 _current_pending_monitor = NULL;
259 _current_pending_monitor_is_from_java = true;
260 _current_waiting_monitor = NULL;
261 _current_pending_raw_monitor = NULL;
262 _num_nested_signal = 0;
263 om_free_list = NULL;
264 om_free_count = 0;
265 om_free_provision = 32;
266 om_in_use_list = NULL;
267 om_in_use_count = 0;
268
269 #ifdef ASSERT
270 _visited_for_critical_count = false;
271 #endif
272
273 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
274 Monitor::_safepoint_check_sometimes);
275 _suspend_flags = 0;
276
277 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
278 _hashStateX = os::random();
279 _hashStateY = 842502087;
280 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
281 _hashStateW = 273326509;
282
283 _OnTrap = 0;
284 _Stalled = 0;
285 _TypeTag = 0x2BAD;
286
287 // Many of the following fields are effectively final - immutable
288 // Note that nascent threads can't use the Native Monitor-Mutex
289 // construct until the _MutexEvent is initialized ...
290 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
291 // we might instead use a stack of ParkEvents that we could provision on-demand.
292 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
293 // and ::Release()
294 _ParkEvent = ParkEvent::Allocate(this);
295 _MuxEvent = ParkEvent::Allocate(this);
296
297 #ifdef CHECK_UNHANDLED_OOPS
298 if (CheckUnhandledOops) {
299 _unhandled_oops = new UnhandledOops(this);
300 }
301 #endif // CHECK_UNHANDLED_OOPS
302 #ifdef ASSERT
303 if (UseBiasedLocking) {
304 assert(is_aligned(this, markWord::biased_lock_alignment), "forced alignment of thread object failed");
305 assert(this == _real_malloc_address ||
306 this == align_up(_real_malloc_address, markWord::biased_lock_alignment),
307 "bug in forced alignment of thread objects");
308 }
309 #endif // ASSERT
310
311 // Notify the barrier set that a thread is being created. The initial
312 // thread is created before the barrier set is available. The call to
313 // BarrierSet::on_thread_create() for this thread is therefore deferred
314 // to BarrierSet::set_barrier_set().
315 BarrierSet* const barrier_set = BarrierSet::barrier_set();
316 if (barrier_set != NULL) {
317 barrier_set->on_thread_create(this);
318 } else {
319 // Only the main thread should be created before the barrier set
320 // and that happens just before Thread::current is set. No other thread
321 // can attach as the VM is not created yet, so they can't execute this code.
322 // If the main thread creates other threads before the barrier set that is an error.
323 assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
324 }
325 }
326
327 void Thread::initialize_thread_current() {
328 #ifndef USE_LIBRARY_BASED_TLS_ONLY
329 assert(_thr_current == NULL, "Thread::current already initialized");
330 _thr_current = this;
331 #endif
332 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
333 ThreadLocalStorage::set_thread(this);
334 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
335 }
336
337 void Thread::clear_thread_current() {
338 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
339 #ifndef USE_LIBRARY_BASED_TLS_ONLY
340 _thr_current = NULL;
341 #endif
342 ThreadLocalStorage::set_thread(NULL);
343 }
344
345 void Thread::record_stack_base_and_size() {
346 // Note: at this point, Thread object is not yet initialized. Do not rely on
347 // any members being initialized. Do not rely on Thread::current() being set.
348 // If possible, refrain from doing anything which may crash or assert since
349 // quite probably those crash dumps will be useless.
350 set_stack_base(os::current_stack_base());
351 set_stack_size(os::current_stack_size());
352
353 #ifdef SOLARIS
354 if (os::is_primordial_thread()) {
355 os::Solaris::correct_stack_boundaries_for_primordial_thread(this);
356 }
357 #endif
358
359 // Set stack limits after thread is initialized.
360 if (is_Java_thread()) {
361 ((JavaThread*) this)->set_stack_overflow_limit();
362 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
363 }
364 }
365
366 #if INCLUDE_NMT
367 void Thread::register_thread_stack_with_NMT() {
368 MemTracker::record_thread_stack(stack_end(), stack_size());
369 }
370 #endif // INCLUDE_NMT
371
372 void Thread::call_run() {
373 DEBUG_ONLY(_run_state = CALL_RUN;)
374
375 // At this point, Thread object should be fully initialized and
376 // Thread::current() should be set.
377
378 assert(Thread::current_or_null() != NULL, "current thread is unset");
379 assert(Thread::current_or_null() == this, "current thread is wrong");
380
381 // Perform common initialization actions
382
383 register_thread_stack_with_NMT();
384
385 JFR_ONLY(Jfr::on_thread_start(this);)
386
387 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
388 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
389 os::current_thread_id(), p2i(stack_base() - stack_size()),
390 p2i(stack_base()), stack_size()/1024);
391
392 // Perform <ChildClass> initialization actions
393 DEBUG_ONLY(_run_state = PRE_RUN;)
394 this->pre_run();
395
396 // Invoke <ChildClass>::run()
397 DEBUG_ONLY(_run_state = RUN;)
398 this->run();
399 // Returned from <ChildClass>::run(). Thread finished.
400
401 // Perform common tear-down actions
402
403 assert(Thread::current_or_null() != NULL, "current thread is unset");
404 assert(Thread::current_or_null() == this, "current thread is wrong");
405
406 // Perform <ChildClass> tear-down actions
407 DEBUG_ONLY(_run_state = POST_RUN;)
408 this->post_run();
409
410 // Note: at this point the thread object may already have deleted itself,
411 // so from here on do not dereference *this*. Not all thread types currently
412 // delete themselves when they terminate. But no thread should ever be deleted
413 // asynchronously with respect to its termination - that is what _run_state can
414 // be used to check.
415
416 assert(Thread::current_or_null() == NULL, "current thread still present");
417 }
418
419 Thread::~Thread() {
420
421 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
422 // get started due to errors etc. Any active thread should at least reach post_run
423 // before it is deleted (usually in post_run()).
424 assert(_run_state == PRE_CALL_RUN ||
425 _run_state == POST_RUN, "Active Thread deleted before post_run(): "
426 "_run_state=%d", (int)_run_state);
427
428 // Notify the barrier set that a thread is being destroyed. Note that a barrier
429 // set might not be available if we encountered errors during bootstrapping.
430 BarrierSet* const barrier_set = BarrierSet::barrier_set();
431 if (barrier_set != NULL) {
432 barrier_set->on_thread_destroy(this);
433 }
434
435 // stack_base can be NULL if the thread is never started or exited before
436 // record_stack_base_and_size called. Although, we would like to ensure
437 // that all started threads do call record_stack_base_and_size(), there is
438 // not proper way to enforce that.
439 #if INCLUDE_NMT
440 if (_stack_base != NULL) {
441 MemTracker::release_thread_stack(stack_end(), stack_size());
442 #ifdef ASSERT
443 set_stack_base(NULL);
444 #endif
445 }
446 #endif // INCLUDE_NMT
447
448 // deallocate data structures
449 delete resource_area();
450 // since the handle marks are using the handle area, we have to deallocated the root
451 // handle mark before deallocating the thread's handle area,
452 assert(last_handle_mark() != NULL, "check we have an element");
453 delete last_handle_mark();
454 assert(last_handle_mark() == NULL, "check we have reached the end");
455
456 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
457 // We NULL out the fields for good hygiene.
458 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
459 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
460
461 delete handle_area();
462 delete metadata_handles();
463
464 // SR_handler uses this as a termination indicator -
465 // needs to happen before os::free_thread()
466 delete _SR_lock;
467 _SR_lock = NULL;
468
469 // osthread() can be NULL, if creation of thread failed.
470 if (osthread() != NULL) os::free_thread(osthread());
471
472 // Clear Thread::current if thread is deleting itself and it has not
473 // already been done. This must be done before the memory is deallocated.
474 // Needed to ensure JNI correctly detects non-attached threads.
475 if (this == Thread::current_or_null()) {
476 Thread::clear_thread_current();
477 }
478
479 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
480 }
481
482 #ifdef ASSERT
483 // A JavaThread is considered "dangling" if it is not the current
484 // thread, has been added the Threads list, the system is not at a
485 // safepoint and the Thread is not "protected".
486 //
487 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
488 assert(!thread->is_Java_thread() || Thread::current() == thread ||
489 !((JavaThread *) thread)->on_thread_list() ||
490 SafepointSynchronize::is_at_safepoint() ||
491 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
492 "possibility of dangling Thread pointer");
493 }
494 #endif
495
496 ThreadPriority Thread::get_priority(const Thread* const thread) {
497 ThreadPriority priority;
498 // Can return an error!
499 (void)os::get_priority(thread, priority);
500 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
501 return priority;
502 }
503
504 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
505 debug_only(check_for_dangling_thread_pointer(thread);)
506 // Can return an error!
507 (void)os::set_priority(thread, priority);
508 }
509
510
511 void Thread::start(Thread* thread) {
512 // Start is different from resume in that its safety is guaranteed by context or
513 // being called from a Java method synchronized on the Thread object.
514 if (!DisableStartThread) {
515 if (thread->is_Java_thread()) {
516 // Initialize the thread state to RUNNABLE before starting this thread.
517 // Can not set it after the thread started because we do not know the
518 // exact thread state at that time. It could be in MONITOR_WAIT or
519 // in SLEEPING or some other state.
520 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
521 java_lang_Thread::RUNNABLE);
522 }
523 os::start_thread(thread);
524 }
525 }
526
527 // Enqueue a VM_Operation to do the job for us - sometime later
528 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
529 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
530 VMThread::execute(vm_stop);
531 }
532
533
534 // Check if an external suspend request has completed (or has been
535 // cancelled). Returns true if the thread is externally suspended and
536 // false otherwise.
537 //
538 // The bits parameter returns information about the code path through
539 // the routine. Useful for debugging:
540 //
541 // set in is_ext_suspend_completed():
542 // 0x00000001 - routine was entered
543 // 0x00000010 - routine return false at end
544 // 0x00000100 - thread exited (return false)
545 // 0x00000200 - suspend request cancelled (return false)
546 // 0x00000400 - thread suspended (return true)
547 // 0x00001000 - thread is in a suspend equivalent state (return true)
548 // 0x00002000 - thread is native and walkable (return true)
549 // 0x00004000 - thread is native_trans and walkable (needed retry)
550 //
551 // set in wait_for_ext_suspend_completion():
552 // 0x00010000 - routine was entered
553 // 0x00020000 - suspend request cancelled before loop (return false)
554 // 0x00040000 - thread suspended before loop (return true)
555 // 0x00080000 - suspend request cancelled in loop (return false)
556 // 0x00100000 - thread suspended in loop (return true)
557 // 0x00200000 - suspend not completed during retry loop (return false)
558
559 // Helper class for tracing suspend wait debug bits.
560 //
561 // 0x00000100 indicates that the target thread exited before it could
562 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
563 // 0x00080000 each indicate a cancelled suspend request so they don't
564 // count as wait failures either.
565 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
566
567 class TraceSuspendDebugBits : public StackObj {
568 private:
569 JavaThread * jt;
570 bool is_wait;
571 bool called_by_wait; // meaningful when !is_wait
572 uint32_t * bits;
573
574 public:
575 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
576 uint32_t *_bits) {
577 jt = _jt;
578 is_wait = _is_wait;
579 called_by_wait = _called_by_wait;
580 bits = _bits;
581 }
582
583 ~TraceSuspendDebugBits() {
584 if (!is_wait) {
585 #if 1
586 // By default, don't trace bits for is_ext_suspend_completed() calls.
587 // That trace is very chatty.
588 return;
589 #else
590 if (!called_by_wait) {
591 // If tracing for is_ext_suspend_completed() is enabled, then only
592 // trace calls to it from wait_for_ext_suspend_completion()
593 return;
594 }
595 #endif
596 }
597
598 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
599 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
600 MutexLocker ml(Threads_lock); // needed for get_thread_name()
601 ResourceMark rm;
602
603 tty->print_cr(
604 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
605 jt->get_thread_name(), *bits);
606
607 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
608 }
609 }
610 }
611 };
612 #undef DEBUG_FALSE_BITS
613
614
615 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
616 uint32_t *bits) {
617 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
618
619 bool did_trans_retry = false; // only do thread_in_native_trans retry once
620 bool do_trans_retry; // flag to force the retry
621
622 *bits |= 0x00000001;
623
624 do {
625 do_trans_retry = false;
626
627 if (is_exiting()) {
628 // Thread is in the process of exiting. This is always checked
629 // first to reduce the risk of dereferencing a freed JavaThread.
630 *bits |= 0x00000100;
631 return false;
632 }
633
634 if (!is_external_suspend()) {
635 // Suspend request is cancelled. This is always checked before
636 // is_ext_suspended() to reduce the risk of a rogue resume
637 // confusing the thread that made the suspend request.
638 *bits |= 0x00000200;
639 return false;
640 }
641
642 if (is_ext_suspended()) {
643 // thread is suspended
644 *bits |= 0x00000400;
645 return true;
646 }
647
648 // Now that we no longer do hard suspends of threads running
649 // native code, the target thread can be changing thread state
650 // while we are in this routine:
651 //
652 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
653 //
654 // We save a copy of the thread state as observed at this moment
655 // and make our decision about suspend completeness based on the
656 // copy. This closes the race where the thread state is seen as
657 // _thread_in_native_trans in the if-thread_blocked check, but is
658 // seen as _thread_blocked in if-thread_in_native_trans check.
659 JavaThreadState save_state = thread_state();
660
661 if (save_state == _thread_blocked && is_suspend_equivalent()) {
662 // If the thread's state is _thread_blocked and this blocking
663 // condition is known to be equivalent to a suspend, then we can
664 // consider the thread to be externally suspended. This means that
665 // the code that sets _thread_blocked has been modified to do
666 // self-suspension if the blocking condition releases. We also
667 // used to check for CONDVAR_WAIT here, but that is now covered by
668 // the _thread_blocked with self-suspension check.
669 //
670 // Return true since we wouldn't be here unless there was still an
671 // external suspend request.
672 *bits |= 0x00001000;
673 return true;
674 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
675 // Threads running native code will self-suspend on native==>VM/Java
676 // transitions. If its stack is walkable (should always be the case
677 // unless this function is called before the actual java_suspend()
678 // call), then the wait is done.
679 *bits |= 0x00002000;
680 return true;
681 } else if (!called_by_wait && !did_trans_retry &&
682 save_state == _thread_in_native_trans &&
683 frame_anchor()->walkable()) {
684 // The thread is transitioning from thread_in_native to another
685 // thread state. check_safepoint_and_suspend_for_native_trans()
686 // will force the thread to self-suspend. If it hasn't gotten
687 // there yet we may have caught the thread in-between the native
688 // code check above and the self-suspend. Lucky us. If we were
689 // called by wait_for_ext_suspend_completion(), then it
690 // will be doing the retries so we don't have to.
691 //
692 // Since we use the saved thread state in the if-statement above,
693 // there is a chance that the thread has already transitioned to
694 // _thread_blocked by the time we get here. In that case, we will
695 // make a single unnecessary pass through the logic below. This
696 // doesn't hurt anything since we still do the trans retry.
697
698 *bits |= 0x00004000;
699
700 // Once the thread leaves thread_in_native_trans for another
701 // thread state, we break out of this retry loop. We shouldn't
702 // need this flag to prevent us from getting back here, but
703 // sometimes paranoia is good.
704 did_trans_retry = true;
705
706 // We wait for the thread to transition to a more usable state.
707 for (int i = 1; i <= SuspendRetryCount; i++) {
708 // We used to do an "os::yield_all(i)" call here with the intention
709 // that yielding would increase on each retry. However, the parameter
710 // is ignored on Linux which means the yield didn't scale up. Waiting
711 // on the SR_lock below provides a much more predictable scale up for
712 // the delay. It also provides a simple/direct point to check for any
713 // safepoint requests from the VMThread
714
715 // temporarily drops SR_lock while doing wait with safepoint check
716 // (if we're a JavaThread - the WatcherThread can also call this)
717 // and increase delay with each retry
718 if (Thread::current()->is_Java_thread()) {
719 SR_lock()->wait(i * delay);
720 } else {
721 SR_lock()->wait_without_safepoint_check(i * delay);
722 }
723
724 // check the actual thread state instead of what we saved above
725 if (thread_state() != _thread_in_native_trans) {
726 // the thread has transitioned to another thread state so
727 // try all the checks (except this one) one more time.
728 do_trans_retry = true;
729 break;
730 }
731 } // end retry loop
732
733
734 }
735 } while (do_trans_retry);
736
737 *bits |= 0x00000010;
738 return false;
739 }
740
741 // Wait for an external suspend request to complete (or be cancelled).
742 // Returns true if the thread is externally suspended and false otherwise.
743 //
744 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
745 uint32_t *bits) {
746 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
747 false /* !called_by_wait */, bits);
748
749 // local flag copies to minimize SR_lock hold time
750 bool is_suspended;
751 bool pending;
752 uint32_t reset_bits;
753
754 // set a marker so is_ext_suspend_completed() knows we are the caller
755 *bits |= 0x00010000;
756
757 // We use reset_bits to reinitialize the bits value at the top of
758 // each retry loop. This allows the caller to make use of any
759 // unused bits for their own marking purposes.
760 reset_bits = *bits;
761
762 {
763 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
764 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
765 delay, bits);
766 pending = is_external_suspend();
767 }
768 // must release SR_lock to allow suspension to complete
769
770 if (!pending) {
771 // A cancelled suspend request is the only false return from
772 // is_ext_suspend_completed() that keeps us from entering the
773 // retry loop.
774 *bits |= 0x00020000;
775 return false;
776 }
777
778 if (is_suspended) {
779 *bits |= 0x00040000;
780 return true;
781 }
782
783 for (int i = 1; i <= retries; i++) {
784 *bits = reset_bits; // reinit to only track last retry
785
786 // We used to do an "os::yield_all(i)" call here with the intention
787 // that yielding would increase on each retry. However, the parameter
788 // is ignored on Linux which means the yield didn't scale up. Waiting
789 // on the SR_lock below provides a much more predictable scale up for
790 // the delay. It also provides a simple/direct point to check for any
791 // safepoint requests from the VMThread
792
793 {
794 Thread* t = Thread::current();
795 MonitorLocker ml(SR_lock(),
796 t->is_Java_thread() ? Mutex::_safepoint_check_flag : Mutex::_no_safepoint_check_flag);
797 // wait with safepoint check (if we're a JavaThread - the WatcherThread
798 // can also call this) and increase delay with each retry
799 ml.wait(i * delay);
800
801 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
802 delay, bits);
803
804 // It is possible for the external suspend request to be cancelled
805 // (by a resume) before the actual suspend operation is completed.
806 // Refresh our local copy to see if we still need to wait.
807 pending = is_external_suspend();
808 }
809
810 if (!pending) {
811 // A cancelled suspend request is the only false return from
812 // is_ext_suspend_completed() that keeps us from staying in the
813 // retry loop.
814 *bits |= 0x00080000;
815 return false;
816 }
817
818 if (is_suspended) {
819 *bits |= 0x00100000;
820 return true;
821 }
822 } // end retry loop
823
824 // thread did not suspend after all our retries
825 *bits |= 0x00200000;
826 return false;
827 }
828
829 // Called from API entry points which perform stack walking. If the
830 // associated JavaThread is the current thread, then wait_for_suspend
831 // is not used. Otherwise, it determines if we should wait for the
832 // "other" thread to complete external suspension. (NOTE: in future
833 // releases the suspension mechanism should be reimplemented so this
834 // is not necessary.)
835 //
836 bool
837 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
838 if (this != JavaThread::current()) {
839 // "other" threads require special handling.
840 if (wait_for_suspend) {
841 // We are allowed to wait for the external suspend to complete
842 // so give the other thread a chance to get suspended.
843 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
844 SuspendRetryDelay, bits)) {
845 // Didn't make it so let the caller know.
846 return false;
847 }
848 }
849 // We aren't allowed to wait for the external suspend to complete
850 // so if the other thread isn't externally suspended we need to
851 // let the caller know.
852 else if (!is_ext_suspend_completed_with_lock(bits)) {
853 return false;
854 }
855 }
856
857 return true;
858 }
859
860 // GC Support
861 bool Thread::claim_par_threads_do(uintx claim_token) {
862 uintx token = _threads_do_token;
863 if (token != claim_token) {
864 uintx res = Atomic::cmpxchg(claim_token, &_threads_do_token, token);
865 if (res == token) {
866 return true;
867 }
868 guarantee(res == claim_token, "invariant");
869 }
870 return false;
871 }
872
873 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
874 active_handles()->oops_do(f);
875 // Do oop for ThreadShadow
876 f->do_oop((oop*)&_pending_exception);
877 handle_area()->oops_do(f);
878
879 // We scan thread local monitor lists here, and the remaining global
880 // monitors in ObjectSynchronizer::oops_do().
881 ObjectSynchronizer::thread_local_used_oops_do(this, f);
882 }
883
884 void Thread::metadata_handles_do(void f(Metadata*)) {
885 // Only walk the Handles in Thread.
886 if (metadata_handles() != NULL) {
887 for (int i = 0; i< metadata_handles()->length(); i++) {
888 f(metadata_handles()->at(i));
889 }
890 }
891 }
892
893 void Thread::print_on(outputStream* st, bool print_extended_info) const {
894 // get_priority assumes osthread initialized
895 if (osthread() != NULL) {
896 int os_prio;
897 if (os::get_native_priority(this, &os_prio) == OS_OK) {
898 st->print("os_prio=%d ", os_prio);
899 }
900
901 st->print("cpu=%.2fms ",
902 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
903 );
904 st->print("elapsed=%.2fs ",
905 _statistical_info.getElapsedTime() / 1000.0
906 );
907 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
908 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
909 st->print("allocated=" SIZE_FORMAT "%s ",
910 byte_size_in_proper_unit(allocated_bytes),
911 proper_unit_for_byte_size(allocated_bytes)
912 );
913 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
914 }
915
916 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
917 osthread()->print_on(st);
918 }
919 ThreadsSMRSupport::print_info_on(this, st);
920 st->print(" ");
921 debug_only(if (WizardMode) print_owned_locks_on(st);)
922 }
923
924 void Thread::print() const { print_on(tty); }
925
926 // Thread::print_on_error() is called by fatal error handler. Don't use
927 // any lock or allocate memory.
928 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
929 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
930
931 if (is_VM_thread()) { st->print("VMThread"); }
932 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
933 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
934 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
935 else { st->print("Thread"); }
936
937 if (is_Named_thread()) {
938 st->print(" \"%s\"", name());
939 }
940
941 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
942 p2i(stack_end()), p2i(stack_base()));
943
944 if (osthread()) {
945 st->print(" [id=%d]", osthread()->thread_id());
946 }
947
948 ThreadsSMRSupport::print_info_on(this, st);
949 }
950
951 void Thread::print_value_on(outputStream* st) const {
952 if (is_Named_thread()) {
953 st->print(" \"%s\" ", name());
954 }
955 st->print(INTPTR_FORMAT, p2i(this)); // print address
956 }
957
958 #ifdef ASSERT
959 void Thread::print_owned_locks_on(outputStream* st) const {
960 Mutex* cur = _owned_locks;
961 if (cur == NULL) {
962 st->print(" (no locks) ");
963 } else {
964 st->print_cr(" Locks owned:");
965 while (cur) {
966 cur->print_on(st);
967 cur = cur->next();
968 }
969 }
970 }
971
972 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
973 void Thread::check_possible_safepoint() {
974 if (!is_Java_thread()) return;
975
976 if (_no_safepoint_count > 0) {
977 print_owned_locks();
978 fatal("Possible safepoint reached by thread that does not allow it");
979 }
980 #ifdef CHECK_UNHANDLED_OOPS
981 // Clear unhandled oops in JavaThreads so we get a crash right away.
982 clear_unhandled_oops();
983 #endif // CHECK_UNHANDLED_OOPS
984 }
985
986 void Thread::check_for_valid_safepoint_state() {
987 if (!is_Java_thread()) return;
988
989 // Check NoSafepointVerifier, which is implied by locks taken that can be
990 // shared with the VM thread. This makes sure that no locks with allow_vm_block
991 // are held.
992 check_possible_safepoint();
993
994 if (((JavaThread*)this)->thread_state() != _thread_in_vm) {
995 fatal("LEAF method calling lock?");
996 }
997
998 if (GCALotAtAllSafepoints) {
999 // We could enter a safepoint here and thus have a gc
1000 InterfaceSupport::check_gc_alot();
1001 }
1002 }
1003 #endif // ASSERT
1004
1005 bool Thread::is_in_stack(address adr) const {
1006 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1007 address end = os::current_stack_pointer();
1008 // Allow non Java threads to call this without stack_base
1009 if (_stack_base == NULL) return true;
1010 if (stack_base() > adr && adr >= end) return true;
1011
1012 return false;
1013 }
1014
1015 bool Thread::is_in_usable_stack(address adr) const {
1016 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1017 size_t usable_stack_size = _stack_size - stack_guard_size;
1018
1019 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1020 }
1021
1022
1023 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1024 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1025 // used for compilation in the future. If that change is made, the need for these methods
1026 // should be revisited, and they should be removed if possible.
1027
1028 bool Thread::is_lock_owned(address adr) const {
1029 return on_local_stack(adr);
1030 }
1031
1032 bool Thread::set_as_starting_thread() {
1033 assert(_starting_thread == NULL, "already initialized: "
1034 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
1035 // NOTE: this must be called inside the main thread.
1036 DEBUG_ONLY(_starting_thread = this;)
1037 return os::create_main_thread((JavaThread*)this);
1038 }
1039
1040 static void initialize_class(Symbol* class_name, TRAPS) {
1041 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1042 InstanceKlass::cast(klass)->initialize(CHECK);
1043 }
1044
1045
1046 // Creates the initial ThreadGroup
1047 static Handle create_initial_thread_group(TRAPS) {
1048 Handle system_instance = JavaCalls::construct_new_instance(
1049 SystemDictionary::ThreadGroup_klass(),
1050 vmSymbols::void_method_signature(),
1051 CHECK_NH);
1052 Universe::set_system_thread_group(system_instance());
1053
1054 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1055 Handle main_instance = JavaCalls::construct_new_instance(
1056 SystemDictionary::ThreadGroup_klass(),
1057 vmSymbols::threadgroup_string_void_signature(),
1058 system_instance,
1059 string,
1060 CHECK_NH);
1061 return main_instance;
1062 }
1063
1064 // Creates the initial Thread
1065 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1066 TRAPS) {
1067 InstanceKlass* ik = SystemDictionary::Thread_klass();
1068 assert(ik->is_initialized(), "must be");
1069 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1070
1071 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1072 // constructor calls Thread.current(), which must be set here for the
1073 // initial thread.
1074 java_lang_Thread::set_thread(thread_oop(), thread);
1075 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1076 thread->set_threadObj(thread_oop());
1077
1078 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1079
1080 JavaValue result(T_VOID);
1081 JavaCalls::call_special(&result, thread_oop,
1082 ik,
1083 vmSymbols::object_initializer_name(),
1084 vmSymbols::threadgroup_string_void_signature(),
1085 thread_group,
1086 string,
1087 CHECK_NULL);
1088 return thread_oop();
1089 }
1090
1091 char java_runtime_name[128] = "";
1092 char java_runtime_version[128] = "";
1093 char java_runtime_vendor_version[128] = "";
1094 char java_runtime_vendor_vm_bug_url[128] = "";
1095
1096 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1097 static const char* get_java_runtime_name(TRAPS) {
1098 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1099 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1100 fieldDescriptor fd;
1101 bool found = k != NULL &&
1102 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1103 vmSymbols::string_signature(), &fd);
1104 if (found) {
1105 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1106 if (name_oop == NULL) {
1107 return NULL;
1108 }
1109 const char* name = java_lang_String::as_utf8_string(name_oop,
1110 java_runtime_name,
1111 sizeof(java_runtime_name));
1112 return name;
1113 } else {
1114 return NULL;
1115 }
1116 }
1117
1118 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1119 static const char* get_java_runtime_version(TRAPS) {
1120 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1121 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1122 fieldDescriptor fd;
1123 bool found = k != NULL &&
1124 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1125 vmSymbols::string_signature(), &fd);
1126 if (found) {
1127 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1128 if (name_oop == NULL) {
1129 return NULL;
1130 }
1131 const char* name = java_lang_String::as_utf8_string(name_oop,
1132 java_runtime_version,
1133 sizeof(java_runtime_version));
1134 return name;
1135 } else {
1136 return NULL;
1137 }
1138 }
1139
1140 // extract the JRE vendor version from java.lang.VersionProps.VENDOR_VERSION
1141 static const char* get_java_runtime_vendor_version(TRAPS) {
1142 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1143 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1144 fieldDescriptor fd;
1145 bool found = k != NULL &&
1146 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_vendor_version_name(),
1147 vmSymbols::string_signature(), &fd);
1148 if (found) {
1149 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1150 if (name_oop == NULL) {
1151 return NULL;
1152 }
1153 const char* name = java_lang_String::as_utf8_string(name_oop,
1154 java_runtime_vendor_version,
1155 sizeof(java_runtime_vendor_version));
1156 return name;
1157 } else {
1158 return NULL;
1159 }
1160 }
1161
1162 // extract the JRE vendor VM bug URL from java.lang.VersionProps.VENDOR_URL_VM_BUG
1163 static const char* get_java_runtime_vendor_vm_bug_url(TRAPS) {
1164 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1165 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1166 fieldDescriptor fd;
1167 bool found = k != NULL &&
1168 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_vendor_vm_bug_url_name(),
1169 vmSymbols::string_signature(), &fd);
1170 if (found) {
1171 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1172 if (name_oop == NULL) {
1173 return NULL;
1174 }
1175 const char* name = java_lang_String::as_utf8_string(name_oop,
1176 java_runtime_vendor_vm_bug_url,
1177 sizeof(java_runtime_vendor_vm_bug_url));
1178 return name;
1179 } else {
1180 return NULL;
1181 }
1182 }
1183
1184 // General purpose hook into Java code, run once when the VM is initialized.
1185 // The Java library method itself may be changed independently from the VM.
1186 static void call_postVMInitHook(TRAPS) {
1187 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1188 if (klass != NULL) {
1189 JavaValue result(T_VOID);
1190 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1191 vmSymbols::void_method_signature(),
1192 CHECK);
1193 }
1194 }
1195
1196 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1197 bool daemon, TRAPS) {
1198 assert(thread_group.not_null(), "thread group should be specified");
1199 assert(threadObj() == NULL, "should only create Java thread object once");
1200
1201 InstanceKlass* ik = SystemDictionary::Thread_klass();
1202 assert(ik->is_initialized(), "must be");
1203 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1204
1205 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1206 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1207 // constructor calls Thread.current(), which must be set here.
1208 java_lang_Thread::set_thread(thread_oop(), this);
1209 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1210 set_threadObj(thread_oop());
1211
1212 JavaValue result(T_VOID);
1213 if (thread_name != NULL) {
1214 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1215 // Thread gets assigned specified name and null target
1216 JavaCalls::call_special(&result,
1217 thread_oop,
1218 ik,
1219 vmSymbols::object_initializer_name(),
1220 vmSymbols::threadgroup_string_void_signature(),
1221 thread_group,
1222 name,
1223 THREAD);
1224 } else {
1225 // Thread gets assigned name "Thread-nnn" and null target
1226 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1227 JavaCalls::call_special(&result,
1228 thread_oop,
1229 ik,
1230 vmSymbols::object_initializer_name(),
1231 vmSymbols::threadgroup_runnable_void_signature(),
1232 thread_group,
1233 Handle(),
1234 THREAD);
1235 }
1236
1237
1238 if (daemon) {
1239 java_lang_Thread::set_daemon(thread_oop());
1240 }
1241
1242 if (HAS_PENDING_EXCEPTION) {
1243 return;
1244 }
1245
1246 Klass* group = SystemDictionary::ThreadGroup_klass();
1247 Handle threadObj(THREAD, this->threadObj());
1248
1249 JavaCalls::call_special(&result,
1250 thread_group,
1251 group,
1252 vmSymbols::add_method_name(),
1253 vmSymbols::thread_void_signature(),
1254 threadObj, // Arg 1
1255 THREAD);
1256 }
1257
1258 // List of all NonJavaThreads and safe iteration over that list.
1259
1260 class NonJavaThread::List {
1261 public:
1262 NonJavaThread* volatile _head;
1263 SingleWriterSynchronizer _protect;
1264
1265 List() : _head(NULL), _protect() {}
1266 };
1267
1268 NonJavaThread::List NonJavaThread::_the_list;
1269
1270 NonJavaThread::Iterator::Iterator() :
1271 _protect_enter(_the_list._protect.enter()),
1272 _current(OrderAccess::load_acquire(&_the_list._head))
1273 {}
1274
1275 NonJavaThread::Iterator::~Iterator() {
1276 _the_list._protect.exit(_protect_enter);
1277 }
1278
1279 void NonJavaThread::Iterator::step() {
1280 assert(!end(), "precondition");
1281 _current = OrderAccess::load_acquire(&_current->_next);
1282 }
1283
1284 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) {
1285 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!");
1286 }
1287
1288 NonJavaThread::~NonJavaThread() { }
1289
1290 void NonJavaThread::add_to_the_list() {
1291 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1292 // Initialize BarrierSet-related data before adding to list.
1293 BarrierSet::barrier_set()->on_thread_attach(this);
1294 OrderAccess::release_store(&_next, _the_list._head);
1295 OrderAccess::release_store(&_the_list._head, this);
1296 }
1297
1298 void NonJavaThread::remove_from_the_list() {
1299 {
1300 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1301 // Cleanup BarrierSet-related data before removing from list.
1302 BarrierSet::barrier_set()->on_thread_detach(this);
1303 NonJavaThread* volatile* p = &_the_list._head;
1304 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) {
1305 if (t == this) {
1306 *p = _next;
1307 break;
1308 }
1309 }
1310 }
1311 // Wait for any in-progress iterators. Concurrent synchronize is not
1312 // allowed, so do it while holding a dedicated lock. Outside and distinct
1313 // from NJTList_lock in case an iteration attempts to lock it.
1314 MutexLocker ml(NonJavaThreadsListSync_lock, Mutex::_no_safepoint_check_flag);
1315 _the_list._protect.synchronize();
1316 _next = NULL; // Safe to drop the link now.
1317 }
1318
1319 void NonJavaThread::pre_run() {
1320 add_to_the_list();
1321
1322 // This is slightly odd in that NamedThread is a subclass, but
1323 // in fact name() is defined in Thread
1324 assert(this->name() != NULL, "thread name was not set before it was started");
1325 this->set_native_thread_name(this->name());
1326 }
1327
1328 void NonJavaThread::post_run() {
1329 JFR_ONLY(Jfr::on_thread_exit(this);)
1330 remove_from_the_list();
1331 // Ensure thread-local-storage is cleared before termination.
1332 Thread::clear_thread_current();
1333 }
1334
1335 // NamedThread -- non-JavaThread subclasses with multiple
1336 // uniquely named instances should derive from this.
1337 NamedThread::NamedThread() :
1338 NonJavaThread(),
1339 _name(NULL),
1340 _processed_thread(NULL),
1341 _gc_id(GCId::undefined())
1342 {}
1343
1344 NamedThread::~NamedThread() {
1345 FREE_C_HEAP_ARRAY(char, _name);
1346 }
1347
1348 void NamedThread::set_name(const char* format, ...) {
1349 guarantee(_name == NULL, "Only get to set name once.");
1350 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1351 va_list ap;
1352 va_start(ap, format);
1353 jio_vsnprintf(_name, max_name_len, format, ap);
1354 va_end(ap);
1355 }
1356
1357 void NamedThread::print_on(outputStream* st) const {
1358 st->print("\"%s\" ", name());
1359 Thread::print_on(st);
1360 st->cr();
1361 }
1362
1363
1364 // ======= WatcherThread ========
1365
1366 // The watcher thread exists to simulate timer interrupts. It should
1367 // be replaced by an abstraction over whatever native support for
1368 // timer interrupts exists on the platform.
1369
1370 WatcherThread* WatcherThread::_watcher_thread = NULL;
1371 bool WatcherThread::_startable = false;
1372 volatile bool WatcherThread::_should_terminate = false;
1373
1374 WatcherThread::WatcherThread() : NonJavaThread() {
1375 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1376 if (os::create_thread(this, os::watcher_thread)) {
1377 _watcher_thread = this;
1378
1379 // Set the watcher thread to the highest OS priority which should not be
1380 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1381 // is created. The only normal thread using this priority is the reference
1382 // handler thread, which runs for very short intervals only.
1383 // If the VMThread's priority is not lower than the WatcherThread profiling
1384 // will be inaccurate.
1385 os::set_priority(this, MaxPriority);
1386 if (!DisableStartThread) {
1387 os::start_thread(this);
1388 }
1389 }
1390 }
1391
1392 int WatcherThread::sleep() const {
1393 // The WatcherThread does not participate in the safepoint protocol
1394 // for the PeriodicTask_lock because it is not a JavaThread.
1395 MonitorLocker ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1396
1397 if (_should_terminate) {
1398 // check for termination before we do any housekeeping or wait
1399 return 0; // we did not sleep.
1400 }
1401
1402 // remaining will be zero if there are no tasks,
1403 // causing the WatcherThread to sleep until a task is
1404 // enrolled
1405 int remaining = PeriodicTask::time_to_wait();
1406 int time_slept = 0;
1407
1408 // we expect this to timeout - we only ever get unparked when
1409 // we should terminate or when a new task has been enrolled
1410 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1411
1412 jlong time_before_loop = os::javaTimeNanos();
1413
1414 while (true) {
1415 bool timedout = ml.wait(remaining);
1416 jlong now = os::javaTimeNanos();
1417
1418 if (remaining == 0) {
1419 // if we didn't have any tasks we could have waited for a long time
1420 // consider the time_slept zero and reset time_before_loop
1421 time_slept = 0;
1422 time_before_loop = now;
1423 } else {
1424 // need to recalculate since we might have new tasks in _tasks
1425 time_slept = (int) ((now - time_before_loop) / 1000000);
1426 }
1427
1428 // Change to task list or spurious wakeup of some kind
1429 if (timedout || _should_terminate) {
1430 break;
1431 }
1432
1433 remaining = PeriodicTask::time_to_wait();
1434 if (remaining == 0) {
1435 // Last task was just disenrolled so loop around and wait until
1436 // another task gets enrolled
1437 continue;
1438 }
1439
1440 remaining -= time_slept;
1441 if (remaining <= 0) {
1442 break;
1443 }
1444 }
1445
1446 return time_slept;
1447 }
1448
1449 void WatcherThread::run() {
1450 assert(this == watcher_thread(), "just checking");
1451
1452 this->set_active_handles(JNIHandleBlock::allocate_block());
1453 while (true) {
1454 assert(watcher_thread() == Thread::current(), "thread consistency check");
1455 assert(watcher_thread() == this, "thread consistency check");
1456
1457 // Calculate how long it'll be until the next PeriodicTask work
1458 // should be done, and sleep that amount of time.
1459 int time_waited = sleep();
1460
1461 if (VMError::is_error_reported()) {
1462 // A fatal error has happened, the error handler(VMError::report_and_die)
1463 // should abort JVM after creating an error log file. However in some
1464 // rare cases, the error handler itself might deadlock. Here periodically
1465 // check for error reporting timeouts, and if it happens, just proceed to
1466 // abort the VM.
1467
1468 // This code is in WatcherThread because WatcherThread wakes up
1469 // periodically so the fatal error handler doesn't need to do anything;
1470 // also because the WatcherThread is less likely to crash than other
1471 // threads.
1472
1473 for (;;) {
1474 // Note: we use naked sleep in this loop because we want to avoid using
1475 // any kind of VM infrastructure which may be broken at this point.
1476 if (VMError::check_timeout()) {
1477 // We hit error reporting timeout. Error reporting was interrupted and
1478 // will be wrapping things up now (closing files etc). Give it some more
1479 // time, then quit the VM.
1480 os::naked_short_sleep(200);
1481 // Print a message to stderr.
1482 fdStream err(defaultStream::output_fd());
1483 err.print_raw_cr("# [ timer expired, abort... ]");
1484 // skip atexit/vm_exit/vm_abort hooks
1485 os::die();
1486 }
1487
1488 // Wait a second, then recheck for timeout.
1489 os::naked_short_sleep(999);
1490 }
1491 }
1492
1493 if (_should_terminate) {
1494 // check for termination before posting the next tick
1495 break;
1496 }
1497
1498 PeriodicTask::real_time_tick(time_waited);
1499 }
1500
1501 // Signal that it is terminated
1502 {
1503 MutexLocker mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1504 _watcher_thread = NULL;
1505 Terminator_lock->notify_all();
1506 }
1507 }
1508
1509 void WatcherThread::start() {
1510 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1511
1512 if (watcher_thread() == NULL && _startable) {
1513 _should_terminate = false;
1514 // Create the single instance of WatcherThread
1515 new WatcherThread();
1516 }
1517 }
1518
1519 void WatcherThread::make_startable() {
1520 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1521 _startable = true;
1522 }
1523
1524 void WatcherThread::stop() {
1525 {
1526 // Follow normal safepoint aware lock enter protocol since the
1527 // WatcherThread is stopped by another JavaThread.
1528 MutexLocker ml(PeriodicTask_lock);
1529 _should_terminate = true;
1530
1531 WatcherThread* watcher = watcher_thread();
1532 if (watcher != NULL) {
1533 // unpark the WatcherThread so it can see that it should terminate
1534 watcher->unpark();
1535 }
1536 }
1537
1538 MonitorLocker mu(Terminator_lock);
1539
1540 while (watcher_thread() != NULL) {
1541 // This wait should make safepoint checks, wait without a timeout,
1542 // and wait as a suspend-equivalent condition.
1543 mu.wait(0, Mutex::_as_suspend_equivalent_flag);
1544 }
1545 }
1546
1547 void WatcherThread::unpark() {
1548 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1549 PeriodicTask_lock->notify();
1550 }
1551
1552 void WatcherThread::print_on(outputStream* st) const {
1553 st->print("\"%s\" ", name());
1554 Thread::print_on(st);
1555 st->cr();
1556 }
1557
1558 // ======= JavaThread ========
1559
1560 #if INCLUDE_JVMCI
1561
1562 jlong* JavaThread::_jvmci_old_thread_counters;
1563
1564 bool jvmci_counters_include(JavaThread* thread) {
1565 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1566 }
1567
1568 void JavaThread::collect_counters(jlong* array, int length) {
1569 assert(length == JVMCICounterSize, "wrong value");
1570 for (int i = 0; i < length; i++) {
1571 array[i] = _jvmci_old_thread_counters[i];
1572 }
1573 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
1574 if (jvmci_counters_include(tp)) {
1575 for (int i = 0; i < length; i++) {
1576 array[i] += tp->_jvmci_counters[i];
1577 }
1578 }
1579 }
1580 }
1581
1582 // Attempt to enlarge the array for per thread counters.
1583 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
1584 jlong* new_counters = NEW_C_HEAP_ARRAY(jlong, new_size, mtJVMCI);
1585 if (old_counters == NULL) {
1586 old_counters = new_counters;
1587 memset(old_counters, 0, sizeof(jlong) * new_size);
1588 } else {
1589 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
1590 new_counters[i] = old_counters[i];
1591 }
1592 if (new_size > current_size) {
1593 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
1594 }
1595 FREE_C_HEAP_ARRAY(jlong, old_counters);
1596 }
1597 return new_counters;
1598 }
1599
1600 // Attempt to enlarge the array for per thread counters.
1601 void JavaThread::resize_counters(int current_size, int new_size) {
1602 _jvmci_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
1603 }
1604
1605 class VM_JVMCIResizeCounters : public VM_Operation {
1606 private:
1607 int _new_size;
1608
1609 public:
1610 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size) { }
1611 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
1612 bool allow_nested_vm_operations() const { return true; }
1613 void doit() {
1614 // Resize the old thread counters array
1615 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
1616 JavaThread::_jvmci_old_thread_counters = new_counters;
1617
1618 // Now resize each threads array
1619 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
1620 tp->resize_counters(JVMCICounterSize, _new_size);
1621 }
1622 JVMCICounterSize = _new_size;
1623 }
1624 };
1625
1626 void JavaThread::resize_all_jvmci_counters(int new_size) {
1627 VM_JVMCIResizeCounters op(new_size);
1628 VMThread::execute(&op);
1629 }
1630
1631 #endif // INCLUDE_JVMCI
1632
1633 // A JavaThread is a normal Java thread
1634
1635 void JavaThread::initialize() {
1636 // Initialize fields
1637
1638 set_saved_exception_pc(NULL);
1639 set_threadObj(NULL);
1640 _anchor.clear();
1641 set_entry_point(NULL);
1642 set_jni_functions(jni_functions());
1643 set_callee_target(NULL);
1644 set_vm_result(NULL);
1645 set_vm_result_2(NULL);
1646 set_vframe_array_head(NULL);
1647 set_vframe_array_last(NULL);
1648 set_deferred_locals(NULL);
1649 set_deopt_mark(NULL);
1650 set_deopt_compiled_method(NULL);
1651 set_monitor_chunks(NULL);
1652 _on_thread_list = false;
1653 _thread_state = _thread_new;
1654 _terminated = _not_terminated;
1655 _array_for_gc = NULL;
1656 _suspend_equivalent = false;
1657 _in_deopt_handler = 0;
1658 _doing_unsafe_access = false;
1659 _stack_guard_state = stack_guard_unused;
1660 #if INCLUDE_JVMCI
1661 _pending_monitorenter = false;
1662 _pending_deoptimization = -1;
1663 _pending_failed_speculation = 0;
1664 _pending_transfer_to_interpreter = false;
1665 _in_retryable_allocation = false;
1666 _jvmci._alternate_call_target = NULL;
1667 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1668 _jvmci_counters = NULL;
1669 if (JVMCICounterSize > 0) {
1670 resize_counters(0, (int) JVMCICounterSize);
1671 }
1672 #endif // INCLUDE_JVMCI
1673 _reserved_stack_activation = NULL; // stack base not known yet
1674 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1675 _exception_pc = 0;
1676 _exception_handler_pc = 0;
1677 _is_method_handle_return = 0;
1678 _jvmti_thread_state= NULL;
1679 _should_post_on_exceptions_flag = JNI_FALSE;
1680 _interp_only_mode = 0;
1681 _special_runtime_exit_condition = _no_async_condition;
1682 _pending_async_exception = NULL;
1683 _thread_stat = NULL;
1684 _thread_stat = new ThreadStatistics();
1685 _jni_active_critical = 0;
1686 _pending_jni_exception_check_fn = NULL;
1687 _do_not_unlock_if_synchronized = false;
1688 _cached_monitor_info = NULL;
1689 _parker = Parker::Allocate(this);
1690 _SleepEvent = ParkEvent::Allocate(this);
1691 // Setup safepoint state info for this thread
1692 ThreadSafepointState::create(this);
1693
1694 debug_only(_java_call_counter = 0);
1695
1696 // JVMTI PopFrame support
1697 _popframe_condition = popframe_inactive;
1698 _popframe_preserved_args = NULL;
1699 _popframe_preserved_args_size = 0;
1700 _frames_to_pop_failed_realloc = 0;
1701
1702 if (SafepointMechanism::uses_thread_local_poll()) {
1703 SafepointMechanism::initialize_header(this);
1704 }
1705
1706 _class_to_be_initialized = NULL;
1707
1708 pd_initialize();
1709 }
1710
1711 JavaThread::JavaThread(bool is_attaching_via_jni) :
1712 Thread() {
1713 initialize();
1714 if (is_attaching_via_jni) {
1715 _jni_attach_state = _attaching_via_jni;
1716 } else {
1717 _jni_attach_state = _not_attaching_via_jni;
1718 }
1719 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1720 }
1721
1722
1723 // interrupt support
1724
1725 void JavaThread::interrupt() {
1726 debug_only(check_for_dangling_thread_pointer(this);)
1727
1728 // For Windows _interrupt_event
1729 osthread()->set_interrupted(true);
1730
1731 // For Thread.sleep
1732 _SleepEvent->unpark();
1733
1734 // For JSR166 LockSupport.park
1735 parker()->unpark();
1736
1737 // For ObjectMonitor and JvmtiRawMonitor
1738 _ParkEvent->unpark();
1739 }
1740
1741
1742 bool JavaThread::is_interrupted(bool clear_interrupted) {
1743 debug_only(check_for_dangling_thread_pointer(this);)
1744
1745 if (threadObj() == NULL) {
1746 // If there is no j.l.Thread then it is impossible to have
1747 // been interrupted. We can find NULL during VM initialization
1748 // or when a JNI thread is still in the process of attaching.
1749 // In such cases this must be the current thread.
1750 assert(this == Thread::current(), "invariant");
1751 return false;
1752 }
1753
1754 bool interrupted = java_lang_Thread::interrupted(threadObj());
1755
1756 // NOTE that since there is no "lock" around the interrupt and
1757 // is_interrupted operations, there is the possibility that the
1758 // interrupted flag will be "false" but that the
1759 // low-level events will be in the signaled state. This is
1760 // intentional. The effect of this is that Object.wait() and
1761 // LockSupport.park() will appear to have a spurious wakeup, which
1762 // is allowed and not harmful, and the possibility is so rare that
1763 // it is not worth the added complexity to add yet another lock.
1764 // For the sleep event an explicit reset is performed on entry
1765 // to JavaThread::sleep, so there is no early return. It has also been
1766 // recommended not to put the interrupted flag into the "event"
1767 // structure because it hides the issue.
1768 // Also, because there is no lock, we must only clear the interrupt
1769 // state if we are going to report that we were interrupted; otherwise
1770 // an interrupt that happens just after we read the field would be lost.
1771 if (interrupted && clear_interrupted) {
1772 assert(this == Thread::current(), "only the current thread can clear");
1773 java_lang_Thread::set_interrupted(threadObj(), false);
1774 osthread()->set_interrupted(false);
1775 }
1776
1777 return interrupted;
1778 }
1779
1780 bool JavaThread::reguard_stack(address cur_sp) {
1781 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1782 && _stack_guard_state != stack_guard_reserved_disabled) {
1783 return true; // Stack already guarded or guard pages not needed.
1784 }
1785
1786 if (register_stack_overflow()) {
1787 // For those architectures which have separate register and
1788 // memory stacks, we must check the register stack to see if
1789 // it has overflowed.
1790 return false;
1791 }
1792
1793 // Java code never executes within the yellow zone: the latter is only
1794 // there to provoke an exception during stack banging. If java code
1795 // is executing there, either StackShadowPages should be larger, or
1796 // some exception code in c1, c2 or the interpreter isn't unwinding
1797 // when it should.
1798 guarantee(cur_sp > stack_reserved_zone_base(),
1799 "not enough space to reguard - increase StackShadowPages");
1800 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1801 enable_stack_yellow_reserved_zone();
1802 if (reserved_stack_activation() != stack_base()) {
1803 set_reserved_stack_activation(stack_base());
1804 }
1805 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1806 set_reserved_stack_activation(stack_base());
1807 enable_stack_reserved_zone();
1808 }
1809 return true;
1810 }
1811
1812 bool JavaThread::reguard_stack(void) {
1813 return reguard_stack(os::current_stack_pointer());
1814 }
1815
1816
1817 void JavaThread::block_if_vm_exited() {
1818 if (_terminated == _vm_exited) {
1819 // _vm_exited is set at safepoint, and Threads_lock is never released
1820 // we will block here forever.
1821 // Here we can be doing a jump from a safe state to an unsafe state without
1822 // proper transition, but it happens after the final safepoint has begun.
1823 set_thread_state(_thread_in_vm);
1824 Threads_lock->lock();
1825 ShouldNotReachHere();
1826 }
1827 }
1828
1829
1830 // Remove this ifdef when C1 is ported to the compiler interface.
1831 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1832 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1833
1834 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1835 Thread() {
1836 initialize();
1837 _jni_attach_state = _not_attaching_via_jni;
1838 set_entry_point(entry_point);
1839 // Create the native thread itself.
1840 // %note runtime_23
1841 os::ThreadType thr_type = os::java_thread;
1842 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1843 os::java_thread;
1844 os::create_thread(this, thr_type, stack_sz);
1845 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1846 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1847 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1848 // the exception consists of creating the exception object & initializing it, initialization
1849 // will leave the VM via a JavaCall and then all locks must be unlocked).
1850 //
1851 // The thread is still suspended when we reach here. Thread must be explicit started
1852 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1853 // by calling Threads:add. The reason why this is not done here, is because the thread
1854 // object must be fully initialized (take a look at JVM_Start)
1855 }
1856
1857 JavaThread::~JavaThread() {
1858
1859 // JSR166 -- return the parker to the free list
1860 Parker::Release(_parker);
1861 _parker = NULL;
1862
1863 // Return the sleep event to the free list
1864 ParkEvent::Release(_SleepEvent);
1865 _SleepEvent = NULL;
1866
1867 // Free any remaining previous UnrollBlock
1868 vframeArray* old_array = vframe_array_last();
1869
1870 if (old_array != NULL) {
1871 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1872 old_array->set_unroll_block(NULL);
1873 delete old_info;
1874 delete old_array;
1875 }
1876
1877 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1878 if (deferred != NULL) {
1879 // This can only happen if thread is destroyed before deoptimization occurs.
1880 assert(deferred->length() != 0, "empty array!");
1881 do {
1882 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1883 deferred->remove_at(0);
1884 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1885 delete dlv;
1886 } while (deferred->length() != 0);
1887 delete deferred;
1888 }
1889
1890 // All Java related clean up happens in exit
1891 ThreadSafepointState::destroy(this);
1892 if (_thread_stat != NULL) delete _thread_stat;
1893
1894 #if INCLUDE_JVMCI
1895 if (JVMCICounterSize > 0) {
1896 if (jvmci_counters_include(this)) {
1897 for (int i = 0; i < JVMCICounterSize; i++) {
1898 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1899 }
1900 }
1901 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1902 }
1903 #endif // INCLUDE_JVMCI
1904 }
1905
1906
1907 // First JavaThread specific code executed by a new Java thread.
1908 void JavaThread::pre_run() {
1909 // empty - see comments in run()
1910 }
1911
1912 // The main routine called by a new Java thread. This isn't overridden
1913 // by subclasses, instead different subclasses define a different "entry_point"
1914 // which defines the actual logic for that kind of thread.
1915 void JavaThread::run() {
1916 // initialize thread-local alloc buffer related fields
1917 this->initialize_tlab();
1918
1919 // Used to test validity of stack trace backs.
1920 // This can't be moved into pre_run() else we invalidate
1921 // the requirement that thread_main_inner is lower on
1922 // the stack. Consequently all the initialization logic
1923 // stays here in run() rather than pre_run().
1924 this->record_base_of_stack_pointer();
1925
1926 this->create_stack_guard_pages();
1927
1928 this->cache_global_variables();
1929
1930 // Thread is now sufficiently initialized to be handled by the safepoint code as being
1931 // in the VM. Change thread state from _thread_new to _thread_in_vm
1932 ThreadStateTransition::transition(this, _thread_new, _thread_in_vm);
1933 // Before a thread is on the threads list it is always safe, so after leaving the
1934 // _thread_new we should emit a instruction barrier. The distance to modified code
1935 // from here is probably far enough, but this is consistent and safe.
1936 OrderAccess::cross_modify_fence();
1937
1938 assert(JavaThread::current() == this, "sanity check");
1939 assert(!Thread::current()->owns_locks(), "sanity check");
1940
1941 DTRACE_THREAD_PROBE(start, this);
1942
1943 // This operation might block. We call that after all safepoint checks for a new thread has
1944 // been completed.
1945 this->set_active_handles(JNIHandleBlock::allocate_block());
1946
1947 if (JvmtiExport::should_post_thread_life()) {
1948 JvmtiExport::post_thread_start(this);
1949
1950 }
1951
1952 // We call another function to do the rest so we are sure that the stack addresses used
1953 // from there will be lower than the stack base just computed.
1954 thread_main_inner();
1955 }
1956
1957 void JavaThread::thread_main_inner() {
1958 assert(JavaThread::current() == this, "sanity check");
1959 assert(this->threadObj() != NULL, "just checking");
1960
1961 // Execute thread entry point unless this thread has a pending exception
1962 // or has been stopped before starting.
1963 // Note: Due to JVM_StopThread we can have pending exceptions already!
1964 if (!this->has_pending_exception() &&
1965 !java_lang_Thread::is_stillborn(this->threadObj())) {
1966 {
1967 ResourceMark rm(this);
1968 this->set_native_thread_name(this->get_thread_name());
1969 }
1970 HandleMark hm(this);
1971 this->entry_point()(this, this);
1972 }
1973
1974 DTRACE_THREAD_PROBE(stop, this);
1975
1976 // Cleanup is handled in post_run()
1977 }
1978
1979 // Shared teardown for all JavaThreads
1980 void JavaThread::post_run() {
1981 this->exit(false);
1982 // Defer deletion to here to ensure 'this' is still referenceable in call_run
1983 // for any shared tear-down.
1984 this->smr_delete();
1985 }
1986
1987 static void ensure_join(JavaThread* thread) {
1988 // We do not need to grab the Threads_lock, since we are operating on ourself.
1989 Handle threadObj(thread, thread->threadObj());
1990 assert(threadObj.not_null(), "java thread object must exist");
1991 ObjectLocker lock(threadObj, thread);
1992 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1993 thread->clear_pending_exception();
1994 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1995 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1996 // Clear the native thread instance - this makes isAlive return false and allows the join()
1997 // to complete once we've done the notify_all below
1998 java_lang_Thread::set_thread(threadObj(), NULL);
1999 lock.notify_all(thread);
2000 // Ignore pending exception (ThreadDeath), since we are exiting anyway
2001 thread->clear_pending_exception();
2002 }
2003
2004 static bool is_daemon(oop threadObj) {
2005 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
2006 }
2007
2008 // For any new cleanup additions, please check to see if they need to be applied to
2009 // cleanup_failed_attach_current_thread as well.
2010 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
2011 assert(this == JavaThread::current(), "thread consistency check");
2012
2013 elapsedTimer _timer_exit_phase1;
2014 elapsedTimer _timer_exit_phase2;
2015 elapsedTimer _timer_exit_phase3;
2016 elapsedTimer _timer_exit_phase4;
2017
2018 if (log_is_enabled(Debug, os, thread, timer)) {
2019 _timer_exit_phase1.start();
2020 }
2021
2022 HandleMark hm(this);
2023 Handle uncaught_exception(this, this->pending_exception());
2024 this->clear_pending_exception();
2025 Handle threadObj(this, this->threadObj());
2026 assert(threadObj.not_null(), "Java thread object should be created");
2027
2028 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
2029 {
2030 EXCEPTION_MARK;
2031
2032 CLEAR_PENDING_EXCEPTION;
2033 }
2034 if (!destroy_vm) {
2035 if (uncaught_exception.not_null()) {
2036 EXCEPTION_MARK;
2037 // Call method Thread.dispatchUncaughtException().
2038 Klass* thread_klass = SystemDictionary::Thread_klass();
2039 JavaValue result(T_VOID);
2040 JavaCalls::call_virtual(&result,
2041 threadObj, thread_klass,
2042 vmSymbols::dispatchUncaughtException_name(),
2043 vmSymbols::throwable_void_signature(),
2044 uncaught_exception,
2045 THREAD);
2046 if (HAS_PENDING_EXCEPTION) {
2047 ResourceMark rm(this);
2048 jio_fprintf(defaultStream::error_stream(),
2049 "\nException: %s thrown from the UncaughtExceptionHandler"
2050 " in thread \"%s\"\n",
2051 pending_exception()->klass()->external_name(),
2052 get_thread_name());
2053 CLEAR_PENDING_EXCEPTION;
2054 }
2055 }
2056 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
2057
2058 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
2059 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
2060 // is deprecated anyhow.
2061 if (!is_Compiler_thread()) {
2062 int count = 3;
2063 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
2064 EXCEPTION_MARK;
2065 JavaValue result(T_VOID);
2066 Klass* thread_klass = SystemDictionary::Thread_klass();
2067 JavaCalls::call_virtual(&result,
2068 threadObj, thread_klass,
2069 vmSymbols::exit_method_name(),
2070 vmSymbols::void_method_signature(),
2071 THREAD);
2072 CLEAR_PENDING_EXCEPTION;
2073 }
2074 }
2075 // notify JVMTI
2076 if (JvmtiExport::should_post_thread_life()) {
2077 JvmtiExport::post_thread_end(this);
2078 }
2079
2080 // We have notified the agents that we are exiting, before we go on,
2081 // we must check for a pending external suspend request and honor it
2082 // in order to not surprise the thread that made the suspend request.
2083 while (true) {
2084 {
2085 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2086 if (!is_external_suspend()) {
2087 set_terminated(_thread_exiting);
2088 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
2089 break;
2090 }
2091 // Implied else:
2092 // Things get a little tricky here. We have a pending external
2093 // suspend request, but we are holding the SR_lock so we
2094 // can't just self-suspend. So we temporarily drop the lock
2095 // and then self-suspend.
2096 }
2097
2098 ThreadBlockInVM tbivm(this);
2099 java_suspend_self();
2100
2101 // We're done with this suspend request, but we have to loop around
2102 // and check again. Eventually we will get SR_lock without a pending
2103 // external suspend request and will be able to mark ourselves as
2104 // exiting.
2105 }
2106 // no more external suspends are allowed at this point
2107 } else {
2108 assert(!is_terminated() && !is_exiting(), "must not be exiting");
2109 // before_exit() has already posted JVMTI THREAD_END events
2110 }
2111
2112 if (log_is_enabled(Debug, os, thread, timer)) {
2113 _timer_exit_phase1.stop();
2114 _timer_exit_phase2.start();
2115 }
2116
2117 // Capture daemon status before the thread is marked as terminated.
2118 bool daemon = is_daemon(threadObj());
2119
2120 // Notify waiters on thread object. This has to be done after exit() is called
2121 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
2122 // group should have the destroyed bit set before waiters are notified).
2123 ensure_join(this);
2124 assert(!this->has_pending_exception(), "ensure_join should have cleared");
2125
2126 if (log_is_enabled(Debug, os, thread, timer)) {
2127 _timer_exit_phase2.stop();
2128 _timer_exit_phase3.start();
2129 }
2130 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
2131 // held by this thread must be released. The spec does not distinguish
2132 // between JNI-acquired and regular Java monitors. We can only see
2133 // regular Java monitors here if monitor enter-exit matching is broken.
2134 //
2135 // ensure_join() ignores IllegalThreadStateExceptions, and so does
2136 // ObjectSynchronizer::release_monitors_owned_by_thread().
2137 if (exit_type == jni_detach) {
2138 // Sanity check even though JNI DetachCurrentThread() would have
2139 // returned JNI_ERR if there was a Java frame. JavaThread exit
2140 // should be done executing Java code by the time we get here.
2141 assert(!this->has_last_Java_frame(),
2142 "should not have a Java frame when detaching or exiting");
2143 ObjectSynchronizer::release_monitors_owned_by_thread(this);
2144 assert(!this->has_pending_exception(), "release_monitors should have cleared");
2145 }
2146
2147 // These things needs to be done while we are still a Java Thread. Make sure that thread
2148 // is in a consistent state, in case GC happens
2149 JFR_ONLY(Jfr::on_thread_exit(this);)
2150
2151 if (active_handles() != NULL) {
2152 JNIHandleBlock* block = active_handles();
2153 set_active_handles(NULL);
2154 JNIHandleBlock::release_block(block);
2155 }
2156
2157 if (free_handle_block() != NULL) {
2158 JNIHandleBlock* block = free_handle_block();
2159 set_free_handle_block(NULL);
2160 JNIHandleBlock::release_block(block);
2161 }
2162
2163 // These have to be removed while this is still a valid thread.
2164 remove_stack_guard_pages();
2165
2166 if (UseTLAB) {
2167 tlab().retire();
2168 }
2169
2170 if (JvmtiEnv::environments_might_exist()) {
2171 JvmtiExport::cleanup_thread(this);
2172 }
2173
2174 // We must flush any deferred card marks and other various GC barrier
2175 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2176 // before removing a thread from the list of active threads.
2177 BarrierSet::barrier_set()->on_thread_detach(this);
2178
2179 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2180 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2181 os::current_thread_id());
2182
2183 if (log_is_enabled(Debug, os, thread, timer)) {
2184 _timer_exit_phase3.stop();
2185 _timer_exit_phase4.start();
2186 }
2187 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2188 Threads::remove(this, daemon);
2189
2190 if (log_is_enabled(Debug, os, thread, timer)) {
2191 _timer_exit_phase4.stop();
2192 ResourceMark rm(this);
2193 log_debug(os, thread, timer)("name='%s'"
2194 ", exit-phase1=" JLONG_FORMAT
2195 ", exit-phase2=" JLONG_FORMAT
2196 ", exit-phase3=" JLONG_FORMAT
2197 ", exit-phase4=" JLONG_FORMAT,
2198 get_thread_name(),
2199 _timer_exit_phase1.milliseconds(),
2200 _timer_exit_phase2.milliseconds(),
2201 _timer_exit_phase3.milliseconds(),
2202 _timer_exit_phase4.milliseconds());
2203 }
2204 }
2205
2206 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
2207 if (active_handles() != NULL) {
2208 JNIHandleBlock* block = active_handles();
2209 set_active_handles(NULL);
2210 JNIHandleBlock::release_block(block);
2211 }
2212
2213 if (free_handle_block() != NULL) {
2214 JNIHandleBlock* block = free_handle_block();
2215 set_free_handle_block(NULL);
2216 JNIHandleBlock::release_block(block);
2217 }
2218
2219 // These have to be removed while this is still a valid thread.
2220 remove_stack_guard_pages();
2221
2222 if (UseTLAB) {
2223 tlab().retire();
2224 }
2225
2226 BarrierSet::barrier_set()->on_thread_detach(this);
2227
2228 Threads::remove(this, is_daemon);
2229 this->smr_delete();
2230 }
2231
2232 JavaThread* JavaThread::active() {
2233 Thread* thread = Thread::current();
2234 if (thread->is_Java_thread()) {
2235 return (JavaThread*) thread;
2236 } else {
2237 assert(thread->is_VM_thread(), "this must be a vm thread");
2238 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2239 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2240 assert(ret->is_Java_thread(), "must be a Java thread");
2241 return ret;
2242 }
2243 }
2244
2245 bool JavaThread::is_lock_owned(address adr) const {
2246 if (Thread::is_lock_owned(adr)) return true;
2247
2248 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2249 if (chunk->contains(adr)) return true;
2250 }
2251
2252 return false;
2253 }
2254
2255
2256 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2257 chunk->set_next(monitor_chunks());
2258 set_monitor_chunks(chunk);
2259 }
2260
2261 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2262 guarantee(monitor_chunks() != NULL, "must be non empty");
2263 if (monitor_chunks() == chunk) {
2264 set_monitor_chunks(chunk->next());
2265 } else {
2266 MonitorChunk* prev = monitor_chunks();
2267 while (prev->next() != chunk) prev = prev->next();
2268 prev->set_next(chunk->next());
2269 }
2270 }
2271
2272 // JVM support.
2273
2274 // Note: this function shouldn't block if it's called in
2275 // _thread_in_native_trans state (such as from
2276 // check_special_condition_for_native_trans()).
2277 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2278
2279 if (has_last_Java_frame() && has_async_condition()) {
2280 // If we are at a polling page safepoint (not a poll return)
2281 // then we must defer async exception because live registers
2282 // will be clobbered by the exception path. Poll return is
2283 // ok because the call we a returning from already collides
2284 // with exception handling registers and so there is no issue.
2285 // (The exception handling path kills call result registers but
2286 // this is ok since the exception kills the result anyway).
2287
2288 if (is_at_poll_safepoint()) {
2289 // if the code we are returning to has deoptimized we must defer
2290 // the exception otherwise live registers get clobbered on the
2291 // exception path before deoptimization is able to retrieve them.
2292 //
2293 RegisterMap map(this, false);
2294 frame caller_fr = last_frame().sender(&map);
2295 assert(caller_fr.is_compiled_frame(), "what?");
2296 if (caller_fr.is_deoptimized_frame()) {
2297 log_info(exceptions)("deferred async exception at compiled safepoint");
2298 return;
2299 }
2300 }
2301 }
2302
2303 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2304 if (condition == _no_async_condition) {
2305 // Conditions have changed since has_special_runtime_exit_condition()
2306 // was called:
2307 // - if we were here only because of an external suspend request,
2308 // then that was taken care of above (or cancelled) so we are done
2309 // - if we were here because of another async request, then it has
2310 // been cleared between the has_special_runtime_exit_condition()
2311 // and now so again we are done
2312 return;
2313 }
2314
2315 // Check for pending async. exception
2316 if (_pending_async_exception != NULL) {
2317 // Only overwrite an already pending exception, if it is not a threadDeath.
2318 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2319
2320 // We cannot call Exceptions::_throw(...) here because we cannot block
2321 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2322
2323 LogTarget(Info, exceptions) lt;
2324 if (lt.is_enabled()) {
2325 ResourceMark rm;
2326 LogStream ls(lt);
2327 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2328 if (has_last_Java_frame()) {
2329 frame f = last_frame();
2330 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2331 }
2332 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2333 }
2334 _pending_async_exception = NULL;
2335 clear_has_async_exception();
2336 }
2337 }
2338
2339 if (check_unsafe_error &&
2340 condition == _async_unsafe_access_error && !has_pending_exception()) {
2341 condition = _no_async_condition; // done
2342 switch (thread_state()) {
2343 case _thread_in_vm: {
2344 JavaThread* THREAD = this;
2345 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2346 }
2347 case _thread_in_native: {
2348 ThreadInVMfromNative tiv(this);
2349 JavaThread* THREAD = this;
2350 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2351 }
2352 case _thread_in_Java: {
2353 ThreadInVMfromJava tiv(this);
2354 JavaThread* THREAD = this;
2355 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2356 }
2357 default:
2358 ShouldNotReachHere();
2359 }
2360 }
2361
2362 assert(condition == _no_async_condition || has_pending_exception() ||
2363 (!check_unsafe_error && condition == _async_unsafe_access_error),
2364 "must have handled the async condition, if no exception");
2365 }
2366
2367 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2368
2369 // Check for pending external suspend.
2370 if (is_external_suspend_with_lock()) {
2371 frame_anchor()->make_walkable(this);
2372 java_suspend_self_with_safepoint_check();
2373 }
2374
2375 // We might be here for reasons in addition to the self-suspend request
2376 // so check for other async requests.
2377 if (check_asyncs) {
2378 check_and_handle_async_exceptions();
2379 }
2380
2381 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2382 }
2383
2384 void JavaThread::send_thread_stop(oop java_throwable) {
2385 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2386 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2387 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2388
2389 // Do not throw asynchronous exceptions against the compiler thread
2390 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2391 if (!can_call_java()) return;
2392
2393 {
2394 // Actually throw the Throwable against the target Thread - however
2395 // only if there is no thread death exception installed already.
2396 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2397 // If the topmost frame is a runtime stub, then we are calling into
2398 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2399 // must deoptimize the caller before continuing, as the compiled exception handler table
2400 // may not be valid
2401 if (has_last_Java_frame()) {
2402 frame f = last_frame();
2403 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2404 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2405 RegisterMap reg_map(this, UseBiasedLocking);
2406 frame compiled_frame = f.sender(®_map);
2407 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2408 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2409 }
2410 }
2411 }
2412
2413 // Set async. pending exception in thread.
2414 set_pending_async_exception(java_throwable);
2415
2416 if (log_is_enabled(Info, exceptions)) {
2417 ResourceMark rm;
2418 log_info(exceptions)("Pending Async. exception installed of type: %s",
2419 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2420 }
2421 // for AbortVMOnException flag
2422 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2423 }
2424 }
2425
2426
2427 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
2428 java_lang_Thread::set_interrupted(threadObj(), true);
2429 this->interrupt();
2430 }
2431
2432 // External suspension mechanism.
2433 //
2434 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2435 // to any VM_locks and it is at a transition
2436 // Self-suspension will happen on the transition out of the vm.
2437 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2438 //
2439 // Guarantees on return:
2440 // + Target thread will not execute any new bytecode (that's why we need to
2441 // force a safepoint)
2442 // + Target thread will not enter any new monitors
2443 //
2444 void JavaThread::java_suspend() {
2445 ThreadsListHandle tlh;
2446 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2447 return;
2448 }
2449
2450 { MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2451 if (!is_external_suspend()) {
2452 // a racing resume has cancelled us; bail out now
2453 return;
2454 }
2455
2456 // suspend is done
2457 uint32_t debug_bits = 0;
2458 // Warning: is_ext_suspend_completed() may temporarily drop the
2459 // SR_lock to allow the thread to reach a stable thread state if
2460 // it is currently in a transient thread state.
2461 if (is_ext_suspend_completed(false /* !called_by_wait */,
2462 SuspendRetryDelay, &debug_bits)) {
2463 return;
2464 }
2465 }
2466
2467 if (Thread::current() == this) {
2468 // Safely self-suspend.
2469 // If we don't do this explicitly it will implicitly happen
2470 // before we transition back to Java, and on some other thread-state
2471 // transition paths, but not as we exit a JVM TI SuspendThread call.
2472 // As SuspendThread(current) must not return (until resumed) we must
2473 // self-suspend here.
2474 ThreadBlockInVM tbivm(this);
2475 java_suspend_self();
2476 } else {
2477 VM_ThreadSuspend vm_suspend;
2478 VMThread::execute(&vm_suspend);
2479 }
2480 }
2481
2482 // Part II of external suspension.
2483 // A JavaThread self suspends when it detects a pending external suspend
2484 // request. This is usually on transitions. It is also done in places
2485 // where continuing to the next transition would surprise the caller,
2486 // e.g., monitor entry.
2487 //
2488 // Returns the number of times that the thread self-suspended.
2489 //
2490 // Note: DO NOT call java_suspend_self() when you just want to block current
2491 // thread. java_suspend_self() is the second stage of cooperative
2492 // suspension for external suspend requests and should only be used
2493 // to complete an external suspend request.
2494 //
2495 int JavaThread::java_suspend_self() {
2496 assert(thread_state() == _thread_blocked, "wrong state for java_suspend_self()");
2497 int ret = 0;
2498
2499 // we are in the process of exiting so don't suspend
2500 if (is_exiting()) {
2501 clear_external_suspend();
2502 return ret;
2503 }
2504
2505 assert(_anchor.walkable() ||
2506 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2507 "must have walkable stack");
2508
2509 MonitorLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2510
2511 assert(!this->is_ext_suspended(),
2512 "a thread trying to self-suspend should not already be suspended");
2513
2514 if (this->is_suspend_equivalent()) {
2515 // If we are self-suspending as a result of the lifting of a
2516 // suspend equivalent condition, then the suspend_equivalent
2517 // flag is not cleared until we set the ext_suspended flag so
2518 // that wait_for_ext_suspend_completion() returns consistent
2519 // results.
2520 this->clear_suspend_equivalent();
2521 }
2522
2523 // A racing resume may have cancelled us before we grabbed SR_lock
2524 // above. Or another external suspend request could be waiting for us
2525 // by the time we return from SR_lock()->wait(). The thread
2526 // that requested the suspension may already be trying to walk our
2527 // stack and if we return now, we can change the stack out from under
2528 // it. This would be a "bad thing (TM)" and cause the stack walker
2529 // to crash. We stay self-suspended until there are no more pending
2530 // external suspend requests.
2531 while (is_external_suspend()) {
2532 ret++;
2533 this->set_ext_suspended();
2534
2535 // _ext_suspended flag is cleared by java_resume()
2536 while (is_ext_suspended()) {
2537 ml.wait();
2538 }
2539 }
2540 return ret;
2541 }
2542
2543 // Helper routine to set up the correct thread state before calling java_suspend_self.
2544 // This is called when regular thread-state transition helpers can't be used because
2545 // we can be in various states, in particular _thread_in_native_trans.
2546 // Because this thread is external suspended the safepoint code will count it as at
2547 // a safepoint, regardless of what its actual current thread-state is. But
2548 // is_ext_suspend_completed() may be waiting to see a thread transition from
2549 // _thread_in_native_trans to _thread_blocked. So we set the thread state directly
2550 // to _thread_blocked. The problem with setting thread state directly is that a
2551 // safepoint could happen just after java_suspend_self() returns after being resumed,
2552 // and the VM thread will see the _thread_blocked state. So we must check for a safepoint
2553 // after restoring the state to make sure we won't leave while a safepoint is in progress.
2554 // However, not all initial-states are allowed when performing a safepoint check, as we
2555 // should never be blocking at a safepoint whilst in those states. Of these 'bad' states
2556 // only _thread_in_native is possible when executing this code (based on our two callers).
2557 // A thread that is _thread_in_native is already safepoint-safe and so it doesn't matter
2558 // whether the VMThread sees the _thread_blocked state, or the _thread_in_native state,
2559 // and so we don't need the explicit safepoint check.
2560
2561 void JavaThread::java_suspend_self_with_safepoint_check() {
2562 assert(this == Thread::current(), "invariant");
2563 JavaThreadState state = thread_state();
2564 set_thread_state(_thread_blocked);
2565 java_suspend_self();
2566 set_thread_state_fence(state);
2567 // Since we are not using a regular thread-state transition helper here,
2568 // we must manually emit the instruction barrier after leaving a safe state.
2569 OrderAccess::cross_modify_fence();
2570 if (state != _thread_in_native) {
2571 SafepointMechanism::block_if_requested(this);
2572 }
2573 }
2574
2575 #ifdef ASSERT
2576 // Verify the JavaThread has not yet been published in the Threads::list, and
2577 // hence doesn't need protection from concurrent access at this stage.
2578 void JavaThread::verify_not_published() {
2579 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2580 // since an unpublished JavaThread doesn't participate in the
2581 // Thread-SMR protocol for keeping a ThreadsList alive.
2582 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2583 }
2584 #endif
2585
2586 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2587 // progress or when _suspend_flags is non-zero.
2588 // Current thread needs to self-suspend if there is a suspend request and/or
2589 // block if a safepoint is in progress.
2590 // Async exception ISN'T checked.
2591 // Note only the ThreadInVMfromNative transition can call this function
2592 // directly and when thread state is _thread_in_native_trans
2593 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2594 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2595
2596 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2597
2598 if (thread->is_external_suspend()) {
2599 thread->java_suspend_self_with_safepoint_check();
2600 } else {
2601 SafepointMechanism::block_if_requested(thread);
2602 }
2603
2604 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2605 }
2606
2607 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2608 // progress or when _suspend_flags is non-zero.
2609 // Current thread needs to self-suspend if there is a suspend request and/or
2610 // block if a safepoint is in progress.
2611 // Also check for pending async exception (not including unsafe access error).
2612 // Note only the native==>VM/Java barriers can call this function and when
2613 // thread state is _thread_in_native_trans.
2614 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2615 check_safepoint_and_suspend_for_native_trans(thread);
2616
2617 if (thread->has_async_exception()) {
2618 // We are in _thread_in_native_trans state, don't handle unsafe
2619 // access error since that may block.
2620 thread->check_and_handle_async_exceptions(false);
2621 }
2622 }
2623
2624 // This is a variant of the normal
2625 // check_special_condition_for_native_trans with slightly different
2626 // semantics for use by critical native wrappers. It does all the
2627 // normal checks but also performs the transition back into
2628 // thread_in_Java state. This is required so that critical natives
2629 // can potentially block and perform a GC if they are the last thread
2630 // exiting the GCLocker.
2631 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2632 check_special_condition_for_native_trans(thread);
2633
2634 // Finish the transition
2635 thread->set_thread_state(_thread_in_Java);
2636
2637 if (thread->do_critical_native_unlock()) {
2638 ThreadInVMfromJavaNoAsyncException tiv(thread);
2639 GCLocker::unlock_critical(thread);
2640 thread->clear_critical_native_unlock();
2641 }
2642 }
2643
2644 // We need to guarantee the Threads_lock here, since resumes are not
2645 // allowed during safepoint synchronization
2646 // Can only resume from an external suspension
2647 void JavaThread::java_resume() {
2648 assert_locked_or_safepoint(Threads_lock);
2649
2650 // Sanity check: thread is gone, has started exiting or the thread
2651 // was not externally suspended.
2652 ThreadsListHandle tlh;
2653 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2654 return;
2655 }
2656
2657 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2658
2659 clear_external_suspend();
2660
2661 if (is_ext_suspended()) {
2662 clear_ext_suspended();
2663 SR_lock()->notify_all();
2664 }
2665 }
2666
2667 size_t JavaThread::_stack_red_zone_size = 0;
2668 size_t JavaThread::_stack_yellow_zone_size = 0;
2669 size_t JavaThread::_stack_reserved_zone_size = 0;
2670 size_t JavaThread::_stack_shadow_zone_size = 0;
2671
2672 void JavaThread::create_stack_guard_pages() {
2673 if (!os::uses_stack_guard_pages() ||
2674 _stack_guard_state != stack_guard_unused ||
2675 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2676 log_info(os, thread)("Stack guard page creation for thread "
2677 UINTX_FORMAT " disabled", os::current_thread_id());
2678 return;
2679 }
2680 address low_addr = stack_end();
2681 size_t len = stack_guard_zone_size();
2682
2683 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2684 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2685
2686 int must_commit = os::must_commit_stack_guard_pages();
2687 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2688
2689 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2690 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2691 return;
2692 }
2693
2694 if (os::guard_memory((char *) low_addr, len)) {
2695 _stack_guard_state = stack_guard_enabled;
2696 } else {
2697 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2698 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2699 if (os::uncommit_memory((char *) low_addr, len)) {
2700 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2701 }
2702 return;
2703 }
2704
2705 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2706 PTR_FORMAT "-" PTR_FORMAT ".",
2707 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2708 }
2709
2710 void JavaThread::remove_stack_guard_pages() {
2711 assert(Thread::current() == this, "from different thread");
2712 if (_stack_guard_state == stack_guard_unused) return;
2713 address low_addr = stack_end();
2714 size_t len = stack_guard_zone_size();
2715
2716 if (os::must_commit_stack_guard_pages()) {
2717 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2718 _stack_guard_state = stack_guard_unused;
2719 } else {
2720 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2721 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2722 return;
2723 }
2724 } else {
2725 if (_stack_guard_state == stack_guard_unused) return;
2726 if (os::unguard_memory((char *) low_addr, len)) {
2727 _stack_guard_state = stack_guard_unused;
2728 } else {
2729 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2730 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2731 return;
2732 }
2733 }
2734
2735 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2736 PTR_FORMAT "-" PTR_FORMAT ".",
2737 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2738 }
2739
2740 void JavaThread::enable_stack_reserved_zone() {
2741 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state");
2742
2743 // The base notation is from the stack's point of view, growing downward.
2744 // We need to adjust it to work correctly with guard_memory()
2745 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2746
2747 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2748 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2749
2750 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2751 _stack_guard_state = stack_guard_enabled;
2752 } else {
2753 warning("Attempt to guard stack reserved zone failed.");
2754 }
2755 enable_register_stack_guard();
2756 }
2757
2758 void JavaThread::disable_stack_reserved_zone() {
2759 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state");
2760
2761 // Simply return if called for a thread that does not use guard pages.
2762 if (_stack_guard_state != stack_guard_enabled) return;
2763
2764 // The base notation is from the stack's point of view, growing downward.
2765 // We need to adjust it to work correctly with guard_memory()
2766 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2767
2768 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2769 _stack_guard_state = stack_guard_reserved_disabled;
2770 } else {
2771 warning("Attempt to unguard stack reserved zone failed.");
2772 }
2773 disable_register_stack_guard();
2774 }
2775
2776 void JavaThread::enable_stack_yellow_reserved_zone() {
2777 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2778 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
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 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2785 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2786
2787 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2788 _stack_guard_state = stack_guard_enabled;
2789 } else {
2790 warning("Attempt to guard stack yellow zone failed.");
2791 }
2792 enable_register_stack_guard();
2793 }
2794
2795 void JavaThread::disable_stack_yellow_reserved_zone() {
2796 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2797 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2798
2799 // Simply return if called for a thread that does not use guard pages.
2800 if (_stack_guard_state == stack_guard_unused) return;
2801
2802 // The base notation is from the stacks point of view, growing downward.
2803 // We need to adjust it to work correctly with guard_memory()
2804 address base = stack_red_zone_base();
2805
2806 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2807 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2808 } else {
2809 warning("Attempt to unguard stack yellow zone failed.");
2810 }
2811 disable_register_stack_guard();
2812 }
2813
2814 void JavaThread::enable_stack_red_zone() {
2815 // The base notation is from the stacks point of view, growing downward.
2816 // We need to adjust it to work correctly with guard_memory()
2817 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2818 address base = stack_red_zone_base() - stack_red_zone_size();
2819
2820 guarantee(base < stack_base(), "Error calculating stack red zone");
2821 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2822
2823 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2824 warning("Attempt to guard stack red zone failed.");
2825 }
2826 }
2827
2828 void JavaThread::disable_stack_red_zone() {
2829 // The base notation is from the stacks point of view, growing downward.
2830 // We need to adjust it to work correctly with guard_memory()
2831 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2832 address base = stack_red_zone_base() - stack_red_zone_size();
2833 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2834 warning("Attempt to unguard stack red zone failed.");
2835 }
2836 }
2837
2838 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2839 // ignore is there is no stack
2840 if (!has_last_Java_frame()) return;
2841 // traverse the stack frames. Starts from top frame.
2842 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2843 frame* fr = fst.current();
2844 f(fr, fst.register_map());
2845 }
2846 }
2847
2848
2849 #ifndef PRODUCT
2850 // Deoptimization
2851 // Function for testing deoptimization
2852 void JavaThread::deoptimize() {
2853 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2854 StackFrameStream fst(this, UseBiasedLocking);
2855 bool deopt = false; // Dump stack only if a deopt actually happens.
2856 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2857 // Iterate over all frames in the thread and deoptimize
2858 for (; !fst.is_done(); fst.next()) {
2859 if (fst.current()->can_be_deoptimized()) {
2860
2861 if (only_at) {
2862 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2863 // consists of comma or carriage return separated numbers so
2864 // search for the current bci in that string.
2865 address pc = fst.current()->pc();
2866 nmethod* nm = (nmethod*) fst.current()->cb();
2867 ScopeDesc* sd = nm->scope_desc_at(pc);
2868 char buffer[8];
2869 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2870 size_t len = strlen(buffer);
2871 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2872 while (found != NULL) {
2873 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2874 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2875 // Check that the bci found is bracketed by terminators.
2876 break;
2877 }
2878 found = strstr(found + 1, buffer);
2879 }
2880 if (!found) {
2881 continue;
2882 }
2883 }
2884
2885 if (DebugDeoptimization && !deopt) {
2886 deopt = true; // One-time only print before deopt
2887 tty->print_cr("[BEFORE Deoptimization]");
2888 trace_frames();
2889 trace_stack();
2890 }
2891 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2892 }
2893 }
2894
2895 if (DebugDeoptimization && deopt) {
2896 tty->print_cr("[AFTER Deoptimization]");
2897 trace_frames();
2898 }
2899 }
2900
2901
2902 // Make zombies
2903 void JavaThread::make_zombies() {
2904 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2905 if (fst.current()->can_be_deoptimized()) {
2906 // it is a Java nmethod
2907 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2908 nm->make_not_entrant();
2909 }
2910 }
2911 }
2912 #endif // PRODUCT
2913
2914
2915 void JavaThread::deoptimize_marked_methods() {
2916 if (!has_last_Java_frame()) return;
2917 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2918 StackFrameStream fst(this, UseBiasedLocking);
2919 for (; !fst.is_done(); fst.next()) {
2920 if (fst.current()->should_be_deoptimized()) {
2921 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2922 }
2923 }
2924 }
2925
2926 // If the caller is a NamedThread, then remember, in the current scope,
2927 // the given JavaThread in its _processed_thread field.
2928 class RememberProcessedThread: public StackObj {
2929 NamedThread* _cur_thr;
2930 public:
2931 RememberProcessedThread(JavaThread* jthr) {
2932 Thread* thread = Thread::current();
2933 if (thread->is_Named_thread()) {
2934 _cur_thr = (NamedThread *)thread;
2935 _cur_thr->set_processed_thread(jthr);
2936 } else {
2937 _cur_thr = NULL;
2938 }
2939 }
2940
2941 ~RememberProcessedThread() {
2942 if (_cur_thr) {
2943 _cur_thr->set_processed_thread(NULL);
2944 }
2945 }
2946 };
2947
2948 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2949 // Verify that the deferred card marks have been flushed.
2950 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2951
2952 // Traverse the GCHandles
2953 Thread::oops_do(f, cf);
2954
2955 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2956 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2957
2958 if (has_last_Java_frame()) {
2959 // Record JavaThread to GC thread
2960 RememberProcessedThread rpt(this);
2961
2962 // traverse the registered growable array
2963 if (_array_for_gc != NULL) {
2964 for (int index = 0; index < _array_for_gc->length(); index++) {
2965 f->do_oop(_array_for_gc->adr_at(index));
2966 }
2967 }
2968
2969 // Traverse the monitor chunks
2970 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2971 chunk->oops_do(f);
2972 }
2973
2974 // Traverse the execution stack
2975 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2976 fst.current()->oops_do(f, cf, fst.register_map());
2977 }
2978 }
2979
2980 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2981 // If we have deferred set_locals there might be oops waiting to be
2982 // written
2983 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2984 if (list != NULL) {
2985 for (int i = 0; i < list->length(); i++) {
2986 list->at(i)->oops_do(f);
2987 }
2988 }
2989
2990 // Traverse instance variables at the end since the GC may be moving things
2991 // around using this function
2992 f->do_oop((oop*) &_threadObj);
2993 f->do_oop((oop*) &_vm_result);
2994 f->do_oop((oop*) &_exception_oop);
2995 f->do_oop((oop*) &_pending_async_exception);
2996
2997 if (jvmti_thread_state() != NULL) {
2998 jvmti_thread_state()->oops_do(f);
2999 }
3000 }
3001
3002 #ifdef ASSERT
3003 void JavaThread::verify_states_for_handshake() {
3004 // This checks that the thread has a correct frame state during a handshake.
3005 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
3006 (has_last_Java_frame() && java_call_counter() > 0),
3007 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
3008 has_last_Java_frame(), java_call_counter());
3009 }
3010 #endif
3011
3012 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
3013 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
3014 (has_last_Java_frame() && java_call_counter() > 0),
3015 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
3016 has_last_Java_frame(), java_call_counter());
3017
3018 if (has_last_Java_frame()) {
3019 // Traverse the execution stack
3020 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3021 fst.current()->nmethods_do(cf);
3022 }
3023 }
3024 }
3025
3026 void JavaThread::metadata_do(MetadataClosure* f) {
3027 if (has_last_Java_frame()) {
3028 // Traverse the execution stack to call f() on the methods in the stack
3029 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3030 fst.current()->metadata_do(f);
3031 }
3032 } else if (is_Compiler_thread()) {
3033 // need to walk ciMetadata in current compile tasks to keep alive.
3034 CompilerThread* ct = (CompilerThread*)this;
3035 if (ct->env() != NULL) {
3036 ct->env()->metadata_do(f);
3037 }
3038 CompileTask* task = ct->task();
3039 if (task != NULL) {
3040 task->metadata_do(f);
3041 }
3042 }
3043 }
3044
3045 // Printing
3046 const char* _get_thread_state_name(JavaThreadState _thread_state) {
3047 switch (_thread_state) {
3048 case _thread_uninitialized: return "_thread_uninitialized";
3049 case _thread_new: return "_thread_new";
3050 case _thread_new_trans: return "_thread_new_trans";
3051 case _thread_in_native: return "_thread_in_native";
3052 case _thread_in_native_trans: return "_thread_in_native_trans";
3053 case _thread_in_vm: return "_thread_in_vm";
3054 case _thread_in_vm_trans: return "_thread_in_vm_trans";
3055 case _thread_in_Java: return "_thread_in_Java";
3056 case _thread_in_Java_trans: return "_thread_in_Java_trans";
3057 case _thread_blocked: return "_thread_blocked";
3058 case _thread_blocked_trans: return "_thread_blocked_trans";
3059 default: return "unknown thread state";
3060 }
3061 }
3062
3063 #ifndef PRODUCT
3064 void JavaThread::print_thread_state_on(outputStream *st) const {
3065 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
3066 };
3067 #endif // PRODUCT
3068
3069 // Called by Threads::print() for VM_PrintThreads operation
3070 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
3071 st->print_raw("\"");
3072 st->print_raw(get_thread_name());
3073 st->print_raw("\" ");
3074 oop thread_oop = threadObj();
3075 if (thread_oop != NULL) {
3076 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
3077 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
3078 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
3079 }
3080 Thread::print_on(st, print_extended_info);
3081 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
3082 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
3083 if (thread_oop != NULL) {
3084 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3085 }
3086 #ifndef PRODUCT
3087 _safepoint_state->print_on(st);
3088 #endif // PRODUCT
3089 if (is_Compiler_thread()) {
3090 CompileTask *task = ((CompilerThread*)this)->task();
3091 if (task != NULL) {
3092 st->print(" Compiling: ");
3093 task->print(st, NULL, true, false);
3094 } else {
3095 st->print(" No compile task");
3096 }
3097 st->cr();
3098 }
3099 }
3100
3101 void JavaThread::print() const { print_on(tty); }
3102
3103 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3104 st->print("%s", get_thread_name_string(buf, buflen));
3105 }
3106
3107 // Called by fatal error handler. The difference between this and
3108 // JavaThread::print() is that we can't grab lock or allocate memory.
3109 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3110 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3111 oop thread_obj = threadObj();
3112 if (thread_obj != NULL) {
3113 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3114 }
3115 st->print(" [");
3116 st->print("%s", _get_thread_state_name(_thread_state));
3117 if (osthread()) {
3118 st->print(", id=%d", osthread()->thread_id());
3119 }
3120 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3121 p2i(stack_end()), p2i(stack_base()));
3122 st->print("]");
3123
3124 ThreadsSMRSupport::print_info_on(this, st);
3125 return;
3126 }
3127
3128 // Verification
3129
3130 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3131
3132 void JavaThread::verify() {
3133 // Verify oops in the thread.
3134 oops_do(&VerifyOopClosure::verify_oop, NULL);
3135
3136 // Verify the stack frames.
3137 frames_do(frame_verify);
3138 }
3139
3140 // CR 6300358 (sub-CR 2137150)
3141 // Most callers of this method assume that it can't return NULL but a
3142 // thread may not have a name whilst it is in the process of attaching to
3143 // the VM - see CR 6412693, and there are places where a JavaThread can be
3144 // seen prior to having it's threadObj set (eg JNI attaching threads and
3145 // if vm exit occurs during initialization). These cases can all be accounted
3146 // for such that this method never returns NULL.
3147 const char* JavaThread::get_thread_name() const {
3148 #ifdef ASSERT
3149 // early safepoints can hit while current thread does not yet have TLS
3150 if (!SafepointSynchronize::is_at_safepoint()) {
3151 Thread *cur = Thread::current();
3152 if (!(cur->is_Java_thread() && cur == this)) {
3153 // Current JavaThreads are allowed to get their own name without
3154 // the Threads_lock.
3155 assert_locked_or_safepoint(Threads_lock);
3156 }
3157 }
3158 #endif // ASSERT
3159 return get_thread_name_string();
3160 }
3161
3162 // Returns a non-NULL representation of this thread's name, or a suitable
3163 // descriptive string if there is no set name
3164 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3165 const char* name_str;
3166 oop thread_obj = threadObj();
3167 if (thread_obj != NULL) {
3168 oop name = java_lang_Thread::name(thread_obj);
3169 if (name != NULL) {
3170 if (buf == NULL) {
3171 name_str = java_lang_String::as_utf8_string(name);
3172 } else {
3173 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3174 }
3175 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3176 name_str = "<no-name - thread is attaching>";
3177 } else {
3178 name_str = Thread::name();
3179 }
3180 } else {
3181 name_str = Thread::name();
3182 }
3183 assert(name_str != NULL, "unexpected NULL thread name");
3184 return name_str;
3185 }
3186
3187 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3188
3189 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3190 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
3191 // Link Java Thread object <-> C++ Thread
3192
3193 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3194 // and put it into a new Handle. The Handle "thread_oop" can then
3195 // be used to pass the C++ thread object to other methods.
3196
3197 // Set the Java level thread object (jthread) field of the
3198 // new thread (a JavaThread *) to C++ thread object using the
3199 // "thread_oop" handle.
3200
3201 // Set the thread field (a JavaThread *) of the
3202 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3203
3204 Handle thread_oop(Thread::current(),
3205 JNIHandles::resolve_non_null(jni_thread));
3206 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3207 "must be initialized");
3208 set_threadObj(thread_oop());
3209 java_lang_Thread::set_thread(thread_oop(), this);
3210
3211 if (prio == NoPriority) {
3212 prio = java_lang_Thread::priority(thread_oop());
3213 assert(prio != NoPriority, "A valid priority should be present");
3214 }
3215
3216 // Push the Java priority down to the native thread; needs Threads_lock
3217 Thread::set_priority(this, prio);
3218
3219 // Add the new thread to the Threads list and set it in motion.
3220 // We must have threads lock in order to call Threads::add.
3221 // It is crucial that we do not block before the thread is
3222 // added to the Threads list for if a GC happens, then the java_thread oop
3223 // will not be visited by GC.
3224 Threads::add(this);
3225 }
3226
3227 oop JavaThread::current_park_blocker() {
3228 // Support for JSR-166 locks
3229 oop thread_oop = threadObj();
3230 if (thread_oop != NULL) {
3231 return java_lang_Thread::park_blocker(thread_oop);
3232 }
3233 return NULL;
3234 }
3235
3236
3237 void JavaThread::print_stack_on(outputStream* st) {
3238 if (!has_last_Java_frame()) return;
3239 ResourceMark rm;
3240 HandleMark hm;
3241
3242 RegisterMap reg_map(this);
3243 vframe* start_vf = last_java_vframe(®_map);
3244 int count = 0;
3245 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3246 if (f->is_java_frame()) {
3247 javaVFrame* jvf = javaVFrame::cast(f);
3248 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3249
3250 // Print out lock information
3251 if (JavaMonitorsInStackTrace) {
3252 jvf->print_lock_info_on(st, count);
3253 }
3254 } else {
3255 // Ignore non-Java frames
3256 }
3257
3258 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3259 count++;
3260 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3261 }
3262 }
3263
3264
3265 // JVMTI PopFrame support
3266 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3267 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3268 if (in_bytes(size_in_bytes) != 0) {
3269 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3270 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3271 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3272 }
3273 }
3274
3275 void* JavaThread::popframe_preserved_args() {
3276 return _popframe_preserved_args;
3277 }
3278
3279 ByteSize JavaThread::popframe_preserved_args_size() {
3280 return in_ByteSize(_popframe_preserved_args_size);
3281 }
3282
3283 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3284 int sz = in_bytes(popframe_preserved_args_size());
3285 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3286 return in_WordSize(sz / wordSize);
3287 }
3288
3289 void JavaThread::popframe_free_preserved_args() {
3290 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3291 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
3292 _popframe_preserved_args = NULL;
3293 _popframe_preserved_args_size = 0;
3294 }
3295
3296 #ifndef PRODUCT
3297
3298 void JavaThread::trace_frames() {
3299 tty->print_cr("[Describe stack]");
3300 int frame_no = 1;
3301 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3302 tty->print(" %d. ", frame_no++);
3303 fst.current()->print_value_on(tty, this);
3304 tty->cr();
3305 }
3306 }
3307
3308 class PrintAndVerifyOopClosure: public OopClosure {
3309 protected:
3310 template <class T> inline void do_oop_work(T* p) {
3311 oop obj = RawAccess<>::oop_load(p);
3312 if (obj == NULL) return;
3313 tty->print(INTPTR_FORMAT ": ", p2i(p));
3314 if (oopDesc::is_oop_or_null(obj)) {
3315 if (obj->is_objArray()) {
3316 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3317 } else {
3318 obj->print();
3319 }
3320 } else {
3321 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3322 }
3323 tty->cr();
3324 }
3325 public:
3326 virtual void do_oop(oop* p) { do_oop_work(p); }
3327 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3328 };
3329
3330 #ifdef ASSERT
3331 // Print or validate the layout of stack frames
3332 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3333 ResourceMark rm;
3334 PRESERVE_EXCEPTION_MARK;
3335 FrameValues values;
3336 int frame_no = 0;
3337 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3338 fst.current()->describe(values, ++frame_no);
3339 if (depth == frame_no) break;
3340 }
3341 if (validate_only) {
3342 values.validate();
3343 } else {
3344 tty->print_cr("[Describe stack layout]");
3345 values.print(this);
3346 }
3347 }
3348 #endif
3349
3350 void JavaThread::trace_stack_from(vframe* start_vf) {
3351 ResourceMark rm;
3352 int vframe_no = 1;
3353 for (vframe* f = start_vf; f; f = f->sender()) {
3354 if (f->is_java_frame()) {
3355 javaVFrame::cast(f)->print_activation(vframe_no++);
3356 } else {
3357 f->print();
3358 }
3359 if (vframe_no > StackPrintLimit) {
3360 tty->print_cr("...<more frames>...");
3361 return;
3362 }
3363 }
3364 }
3365
3366
3367 void JavaThread::trace_stack() {
3368 if (!has_last_Java_frame()) return;
3369 ResourceMark rm;
3370 HandleMark hm;
3371 RegisterMap reg_map(this);
3372 trace_stack_from(last_java_vframe(®_map));
3373 }
3374
3375
3376 #endif // PRODUCT
3377
3378
3379 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3380 assert(reg_map != NULL, "a map must be given");
3381 frame f = last_frame();
3382 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3383 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3384 }
3385 return NULL;
3386 }
3387
3388
3389 Klass* JavaThread::security_get_caller_class(int depth) {
3390 vframeStream vfst(this);
3391 vfst.security_get_caller_frame(depth);
3392 if (!vfst.at_end()) {
3393 return vfst.method()->method_holder();
3394 }
3395 return NULL;
3396 }
3397
3398 // java.lang.Thread.sleep support
3399 // Returns true if sleep time elapsed as expected, and false
3400 // if the thread was interrupted.
3401 bool JavaThread::sleep(jlong millis) {
3402 assert(this == Thread::current(), "thread consistency check");
3403
3404 ParkEvent * const slp = this->_SleepEvent;
3405 // Because there can be races with thread interruption sending an unpark()
3406 // to the event, we explicitly reset it here to avoid an immediate return.
3407 // The actual interrupt state will be checked before we park().
3408 slp->reset();
3409 // Thread interruption establishes a happens-before ordering in the
3410 // Java Memory Model, so we need to ensure we synchronize with the
3411 // interrupt state.
3412 OrderAccess::fence();
3413
3414 jlong prevtime = os::javaTimeNanos();
3415
3416 for (;;) {
3417 // interruption has precedence over timing out
3418 if (this->is_interrupted(true)) {
3419 return false;
3420 }
3421
3422 if (millis <= 0) {
3423 return true;
3424 }
3425
3426 {
3427 ThreadBlockInVM tbivm(this);
3428 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
3429
3430 this->set_suspend_equivalent();
3431 // cleared by handle_special_suspend_equivalent_condition() or
3432 // java_suspend_self() via check_and_wait_while_suspended()
3433
3434 slp->park(millis);
3435
3436 // were we externally suspended while we were waiting?
3437 this->check_and_wait_while_suspended();
3438 }
3439
3440 // Update elapsed time tracking
3441 jlong newtime = os::javaTimeNanos();
3442 if (newtime - prevtime < 0) {
3443 // time moving backwards, should only happen if no monotonic clock
3444 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3445 assert(!os::supports_monotonic_clock(),
3446 "unexpected time moving backwards detected in JavaThread::sleep()");
3447 } else {
3448 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3449 }
3450 prevtime = newtime;
3451 }
3452 }
3453
3454 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3455 assert(thread->is_Compiler_thread(), "must be compiler thread");
3456 CompileBroker::compiler_thread_loop();
3457 }
3458
3459 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3460 NMethodSweeper::sweeper_loop();
3461 }
3462
3463 // Create a CompilerThread
3464 CompilerThread::CompilerThread(CompileQueue* queue,
3465 CompilerCounters* counters)
3466 : JavaThread(&compiler_thread_entry) {
3467 _env = NULL;
3468 _log = NULL;
3469 _task = NULL;
3470 _queue = queue;
3471 _counters = counters;
3472 _buffer_blob = NULL;
3473 _compiler = NULL;
3474
3475 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3476 resource_area()->bias_to(mtCompiler);
3477
3478 #ifndef PRODUCT
3479 _ideal_graph_printer = NULL;
3480 #endif
3481 }
3482
3483 CompilerThread::~CompilerThread() {
3484 // Delete objects which were allocated on heap.
3485 delete _counters;
3486 }
3487
3488 bool CompilerThread::can_call_java() const {
3489 return _compiler != NULL && _compiler->is_jvmci();
3490 }
3491
3492 // Create sweeper thread
3493 CodeCacheSweeperThread::CodeCacheSweeperThread()
3494 : JavaThread(&sweeper_thread_entry) {
3495 _scanned_compiled_method = NULL;
3496 }
3497
3498 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3499 JavaThread::oops_do(f, cf);
3500 if (_scanned_compiled_method != NULL && cf != NULL) {
3501 // Safepoints can occur when the sweeper is scanning an nmethod so
3502 // process it here to make sure it isn't unloaded in the middle of
3503 // a scan.
3504 cf->do_code_blob(_scanned_compiled_method);
3505 }
3506 }
3507
3508 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3509 JavaThread::nmethods_do(cf);
3510 if (_scanned_compiled_method != NULL && cf != NULL) {
3511 // Safepoints can occur when the sweeper is scanning an nmethod so
3512 // process it here to make sure it isn't unloaded in the middle of
3513 // a scan.
3514 cf->do_code_blob(_scanned_compiled_method);
3515 }
3516 }
3517
3518
3519 // ======= Threads ========
3520
3521 // The Threads class links together all active threads, and provides
3522 // operations over all threads. It is protected by the Threads_lock,
3523 // which is also used in other global contexts like safepointing.
3524 // ThreadsListHandles are used to safely perform operations on one
3525 // or more threads without the risk of the thread exiting during the
3526 // operation.
3527 //
3528 // Note: The Threads_lock is currently more widely used than we
3529 // would like. We are actively migrating Threads_lock uses to other
3530 // mechanisms in order to reduce Threads_lock contention.
3531
3532 int Threads::_number_of_threads = 0;
3533 int Threads::_number_of_non_daemon_threads = 0;
3534 int Threads::_return_code = 0;
3535 uintx Threads::_thread_claim_token = 1; // Never zero.
3536 size_t JavaThread::_stack_size_at_create = 0;
3537
3538 #ifdef ASSERT
3539 bool Threads::_vm_complete = false;
3540 #endif
3541
3542 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3543 Prefetch::read((void*)addr, prefetch_interval);
3544 return *addr;
3545 }
3546
3547 // Possibly the ugliest for loop the world has seen. C++ does not allow
3548 // multiple types in the declaration section of the for loop. In this case
3549 // we are only dealing with pointers and hence can cast them. It looks ugly
3550 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3551 #define DO_JAVA_THREADS(LIST, X) \
3552 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3553 *MACRO_list = (JavaThread*)(LIST), \
3554 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3555 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3556 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3557 MACRO_current_p != MACRO_end; \
3558 MACRO_current_p++, \
3559 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3560
3561 // All JavaThreads
3562 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3563
3564 // All NonJavaThreads (i.e., every non-JavaThread in the system).
3565 void Threads::non_java_threads_do(ThreadClosure* tc) {
3566 NoSafepointVerifier nsv;
3567 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
3568 tc->do_thread(njti.current());
3569 }
3570 }
3571
3572 // All JavaThreads
3573 void Threads::java_threads_do(ThreadClosure* tc) {
3574 assert_locked_or_safepoint(Threads_lock);
3575 // ALL_JAVA_THREADS iterates through all JavaThreads.
3576 ALL_JAVA_THREADS(p) {
3577 tc->do_thread(p);
3578 }
3579 }
3580
3581 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3582 assert_locked_or_safepoint(Threads_lock);
3583 java_threads_do(tc);
3584 tc->do_thread(VMThread::vm_thread());
3585 }
3586
3587 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3588 void Threads::threads_do(ThreadClosure* tc) {
3589 assert_locked_or_safepoint(Threads_lock);
3590 java_threads_do(tc);
3591 non_java_threads_do(tc);
3592 }
3593
3594 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3595 uintx claim_token = Threads::thread_claim_token();
3596 ALL_JAVA_THREADS(p) {
3597 if (p->claim_threads_do(is_par, claim_token)) {
3598 tc->do_thread(p);
3599 }
3600 }
3601 VMThread* vmt = VMThread::vm_thread();
3602 if (vmt->claim_threads_do(is_par, claim_token)) {
3603 tc->do_thread(vmt);
3604 }
3605 }
3606
3607 // The system initialization in the library has three phases.
3608 //
3609 // Phase 1: java.lang.System class initialization
3610 // java.lang.System is a primordial class loaded and initialized
3611 // by the VM early during startup. java.lang.System.<clinit>
3612 // only does registerNatives and keeps the rest of the class
3613 // initialization work later until thread initialization completes.
3614 //
3615 // System.initPhase1 initializes the system properties, the static
3616 // fields in, out, and err. Set up java signal handlers, OS-specific
3617 // system settings, and thread group of the main thread.
3618 static void call_initPhase1(TRAPS) {
3619 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3620 JavaValue result(T_VOID);
3621 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3622 vmSymbols::void_method_signature(), CHECK);
3623 }
3624
3625 // Phase 2. Module system initialization
3626 // This will initialize the module system. Only java.base classes
3627 // can be loaded until phase 2 completes.
3628 //
3629 // Call System.initPhase2 after the compiler initialization and jsr292
3630 // classes get initialized because module initialization runs a lot of java
3631 // code, that for performance reasons, should be compiled. Also, this will
3632 // enable the startup code to use lambda and other language features in this
3633 // phase and onward.
3634 //
3635 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3636 static void call_initPhase2(TRAPS) {
3637 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3638
3639 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3640
3641 JavaValue result(T_INT);
3642 JavaCallArguments args;
3643 args.push_int(DisplayVMOutputToStderr);
3644 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3645 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3646 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3647 if (result.get_jint() != JNI_OK) {
3648 vm_exit_during_initialization(); // no message or exception
3649 }
3650
3651 universe_post_module_init();
3652 }
3653
3654 // Phase 3. final setup - set security manager, system class loader and TCCL
3655 //
3656 // This will instantiate and set the security manager, set the system class
3657 // loader as well as the thread context class loader. The security manager
3658 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3659 // other modules or the application's classpath.
3660 static void call_initPhase3(TRAPS) {
3661 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3662 JavaValue result(T_VOID);
3663 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3664 vmSymbols::void_method_signature(), CHECK);
3665 }
3666
3667 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3668 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3669
3670 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3671 create_vm_init_libraries();
3672 }
3673
3674 initialize_class(vmSymbols::java_lang_String(), CHECK);
3675
3676 // Inject CompactStrings value after the static initializers for String ran.
3677 java_lang_String::set_compact_strings(CompactStrings);
3678
3679 // Initialize java_lang.System (needed before creating the thread)
3680 initialize_class(vmSymbols::java_lang_System(), CHECK);
3681 // The VM creates & returns objects of this class. Make sure it's initialized.
3682 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3683 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3684 Handle thread_group = create_initial_thread_group(CHECK);
3685 Universe::set_main_thread_group(thread_group());
3686 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3687 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3688 main_thread->set_threadObj(thread_object);
3689
3690 // Set thread status to running since main thread has
3691 // been started and running.
3692 java_lang_Thread::set_thread_status(thread_object,
3693 java_lang_Thread::RUNNABLE);
3694
3695 // The VM creates objects of this class.
3696 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3697
3698 #ifdef ASSERT
3699 InstanceKlass *k = SystemDictionary::UnsafeConstants_klass();
3700 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
3701 #endif
3702
3703 // initialize the hardware-specific constants needed by Unsafe
3704 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
3705 jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
3706
3707 // The VM preresolves methods to these classes. Make sure that they get initialized
3708 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3709 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3710
3711 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3712 call_initPhase1(CHECK);
3713
3714 // get the Java runtime name, version, and vendor info after java.lang.System is initialized
3715 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3716 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3717 JDK_Version::set_runtime_vendor_version(get_java_runtime_vendor_version(THREAD));
3718 JDK_Version::set_runtime_vendor_vm_bug_url(get_java_runtime_vendor_vm_bug_url(THREAD));
3719
3720 // an instance of OutOfMemory exception has been allocated earlier
3721 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3722 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3723 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3724 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3725 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3726 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3727 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3728 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3729
3730 // Eager box cache initialization only if AOT is on and any library is loaded.
3731 AOTLoader::initialize_box_caches(CHECK);
3732 }
3733
3734 void Threads::initialize_jsr292_core_classes(TRAPS) {
3735 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3736
3737 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3738 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3739 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3740 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3741 }
3742
3743 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3744 extern void JDK_Version_init();
3745
3746 // Preinitialize version info.
3747 VM_Version::early_initialize();
3748
3749 // Check version
3750 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3751
3752 // Initialize library-based TLS
3753 ThreadLocalStorage::init();
3754
3755 // Initialize the output stream module
3756 ostream_init();
3757
3758 // Process java launcher properties.
3759 Arguments::process_sun_java_launcher_properties(args);
3760
3761 // Initialize the os module
3762 os::init();
3763
3764 // Record VM creation timing statistics
3765 TraceVmCreationTime create_vm_timer;
3766 create_vm_timer.start();
3767
3768 // Initialize system properties.
3769 Arguments::init_system_properties();
3770
3771 // So that JDK version can be used as a discriminator when parsing arguments
3772 JDK_Version_init();
3773
3774 // Update/Initialize System properties after JDK version number is known
3775 Arguments::init_version_specific_system_properties();
3776
3777 // Make sure to initialize log configuration *before* parsing arguments
3778 LogConfiguration::initialize(create_vm_timer.begin_time());
3779
3780 // Parse arguments
3781 // Note: this internally calls os::init_container_support()
3782 jint parse_result = Arguments::parse(args);
3783 if (parse_result != JNI_OK) return parse_result;
3784
3785 os::init_before_ergo();
3786
3787 jint ergo_result = Arguments::apply_ergo();
3788 if (ergo_result != JNI_OK) return ergo_result;
3789
3790 // Final check of all ranges after ergonomics which may change values.
3791 if (!JVMFlagRangeList::check_ranges()) {
3792 return JNI_EINVAL;
3793 }
3794
3795 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3796 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo);
3797 if (!constraint_result) {
3798 return JNI_EINVAL;
3799 }
3800
3801 JVMFlagWriteableList::mark_startup();
3802
3803 if (PauseAtStartup) {
3804 os::pause();
3805 }
3806
3807 HOTSPOT_VM_INIT_BEGIN();
3808
3809 // Timing (must come after argument parsing)
3810 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3811
3812 // Initialize the os module after parsing the args
3813 jint os_init_2_result = os::init_2();
3814 if (os_init_2_result != JNI_OK) return os_init_2_result;
3815
3816 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3817 // Initialize assert poison page mechanism.
3818 if (ShowRegistersOnAssert) {
3819 initialize_assert_poison();
3820 }
3821 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3822
3823 SafepointMechanism::initialize();
3824
3825 jint adjust_after_os_result = Arguments::adjust_after_os();
3826 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3827
3828 // Initialize output stream logging
3829 ostream_init_log();
3830
3831 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3832 // Must be before create_vm_init_agents()
3833 if (Arguments::init_libraries_at_startup()) {
3834 convert_vm_init_libraries_to_agents();
3835 }
3836
3837 // Launch -agentlib/-agentpath and converted -Xrun agents
3838 if (Arguments::init_agents_at_startup()) {
3839 create_vm_init_agents();
3840 }
3841
3842 // Initialize Threads state
3843 _number_of_threads = 0;
3844 _number_of_non_daemon_threads = 0;
3845
3846 // Initialize global data structures and create system classes in heap
3847 vm_init_globals();
3848
3849 #if INCLUDE_JVMCI
3850 if (JVMCICounterSize > 0) {
3851 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
3852 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3853 } else {
3854 JavaThread::_jvmci_old_thread_counters = NULL;
3855 }
3856 #endif // INCLUDE_JVMCI
3857
3858 // Attach the main thread to this os thread
3859 JavaThread* main_thread = new JavaThread();
3860 main_thread->set_thread_state(_thread_in_vm);
3861 main_thread->initialize_thread_current();
3862 // must do this before set_active_handles
3863 main_thread->record_stack_base_and_size();
3864 main_thread->register_thread_stack_with_NMT();
3865 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3866
3867 if (!main_thread->set_as_starting_thread()) {
3868 vm_shutdown_during_initialization(
3869 "Failed necessary internal allocation. Out of swap space");
3870 main_thread->smr_delete();
3871 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3872 return JNI_ENOMEM;
3873 }
3874
3875 // Enable guard page *after* os::create_main_thread(), otherwise it would
3876 // crash Linux VM, see notes in os_linux.cpp.
3877 main_thread->create_stack_guard_pages();
3878
3879 // Initialize Java-Level synchronization subsystem
3880 ObjectMonitor::Initialize();
3881
3882 // Initialize global modules
3883 jint status = init_globals();
3884 if (status != JNI_OK) {
3885 main_thread->smr_delete();
3886 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3887 return status;
3888 }
3889
3890 JFR_ONLY(Jfr::on_vm_init();)
3891
3892 // Should be done after the heap is fully created
3893 main_thread->cache_global_variables();
3894
3895 HandleMark hm;
3896
3897 { MutexLocker mu(Threads_lock);
3898 Threads::add(main_thread);
3899 }
3900
3901 // Any JVMTI raw monitors entered in onload will transition into
3902 // real raw monitor. VM is setup enough here for raw monitor enter.
3903 JvmtiExport::transition_pending_onload_raw_monitors();
3904
3905 // Create the VMThread
3906 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3907
3908 VMThread::create();
3909 Thread* vmthread = VMThread::vm_thread();
3910
3911 if (!os::create_thread(vmthread, os::vm_thread)) {
3912 vm_exit_during_initialization("Cannot create VM thread. "
3913 "Out of system resources.");
3914 }
3915
3916 // Wait for the VM thread to become ready, and VMThread::run to initialize
3917 // Monitors can have spurious returns, must always check another state flag
3918 {
3919 MonitorLocker ml(Notify_lock);
3920 os::start_thread(vmthread);
3921 while (vmthread->active_handles() == NULL) {
3922 ml.wait();
3923 }
3924 }
3925 }
3926
3927 assert(Universe::is_fully_initialized(), "not initialized");
3928 if (VerifyDuringStartup) {
3929 // Make sure we're starting with a clean slate.
3930 VM_Verify verify_op;
3931 VMThread::execute(&verify_op);
3932 }
3933
3934 // We need this to update the java.vm.info property in case any flags used
3935 // to initially define it have been changed. This is needed for both CDS and
3936 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info
3937 // is initially computed. See Abstract_VM_Version::vm_info_string().
3938 // This update must happen before we initialize the java classes, but
3939 // after any initialization logic that might modify the flags.
3940 Arguments::update_vm_info_property(VM_Version::vm_info_string());
3941
3942 Thread* THREAD = Thread::current();
3943
3944 // Always call even when there are not JVMTI environments yet, since environments
3945 // may be attached late and JVMTI must track phases of VM execution
3946 JvmtiExport::enter_early_start_phase();
3947
3948 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3949 JvmtiExport::post_early_vm_start();
3950
3951 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3952
3953 quicken_jni_functions();
3954
3955 // No more stub generation allowed after that point.
3956 StubCodeDesc::freeze();
3957
3958 // Set flag that basic initialization has completed. Used by exceptions and various
3959 // debug stuff, that does not work until all basic classes have been initialized.
3960 set_init_completed();
3961
3962 LogConfiguration::post_initialize();
3963 Metaspace::post_initialize();
3964
3965 HOTSPOT_VM_INIT_END();
3966
3967 // record VM initialization completion time
3968 #if INCLUDE_MANAGEMENT
3969 Management::record_vm_init_completed();
3970 #endif // INCLUDE_MANAGEMENT
3971
3972 // Signal Dispatcher needs to be started before VMInit event is posted
3973 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3974
3975 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3976 if (!DisableAttachMechanism) {
3977 AttachListener::vm_start();
3978 if (StartAttachListener || AttachListener::init_at_startup()) {
3979 AttachListener::init();
3980 }
3981 }
3982
3983 // Launch -Xrun agents
3984 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3985 // back-end can launch with -Xdebug -Xrunjdwp.
3986 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3987 create_vm_init_libraries();
3988 }
3989
3990 if (CleanChunkPoolAsync) {
3991 Chunk::start_chunk_pool_cleaner_task();
3992 }
3993
3994
3995 // initialize compiler(s)
3996 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3997 #if INCLUDE_JVMCI
3998 bool force_JVMCI_intialization = false;
3999 if (EnableJVMCI) {
4000 // Initialize JVMCI eagerly when it is explicitly requested.
4001 // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
4002 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
4003
4004 if (!force_JVMCI_intialization) {
4005 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
4006 // compilations via JVMCI will not actually block until JVMCI is initialized.
4007 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
4008 }
4009 }
4010 #endif
4011 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
4012 // Postpone completion of compiler initialization to after JVMCI
4013 // is initialized to avoid timeouts of blocking compilations.
4014 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
4015 CompileBroker::compilation_init_phase2();
4016 }
4017 #endif
4018
4019 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
4020 // It is done after compilers are initialized, because otherwise compilations of
4021 // signature polymorphic MH intrinsics can be missed
4022 // (see SystemDictionary::find_method_handle_intrinsic).
4023 initialize_jsr292_core_classes(CHECK_JNI_ERR);
4024
4025 // This will initialize the module system. Only java.base classes can be
4026 // loaded until phase 2 completes
4027 call_initPhase2(CHECK_JNI_ERR);
4028
4029 // Always call even when there are not JVMTI environments yet, since environments
4030 // may be attached late and JVMTI must track phases of VM execution
4031 JvmtiExport::enter_start_phase();
4032
4033 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
4034 JvmtiExport::post_vm_start();
4035
4036 // Final system initialization including security manager and system class loader
4037 call_initPhase3(CHECK_JNI_ERR);
4038
4039 // cache the system and platform class loaders
4040 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
4041
4042 #if INCLUDE_CDS
4043 // capture the module path info from the ModuleEntryTable
4044 ClassLoader::initialize_module_path(THREAD);
4045 #endif
4046
4047 #if INCLUDE_JVMCI
4048 if (force_JVMCI_intialization) {
4049 JVMCI::initialize_compiler(CHECK_JNI_ERR);
4050 CompileBroker::compilation_init_phase2();
4051 }
4052 #endif
4053
4054 // Always call even when there are not JVMTI environments yet, since environments
4055 // may be attached late and JVMTI must track phases of VM execution
4056 JvmtiExport::enter_live_phase();
4057
4058 // Make perfmemory accessible
4059 PerfMemory::set_accessible(true);
4060
4061 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
4062 JvmtiExport::post_vm_initialized();
4063
4064 JFR_ONLY(Jfr::on_vm_start();)
4065
4066 #if INCLUDE_MANAGEMENT
4067 Management::initialize(THREAD);
4068
4069 if (HAS_PENDING_EXCEPTION) {
4070 // management agent fails to start possibly due to
4071 // configuration problem and is responsible for printing
4072 // stack trace if appropriate. Simply exit VM.
4073 vm_exit(1);
4074 }
4075 #endif // INCLUDE_MANAGEMENT
4076
4077 if (MemProfiling) MemProfiler::engage();
4078 StatSampler::engage();
4079 if (CheckJNICalls) JniPeriodicChecker::engage();
4080
4081 BiasedLocking::init();
4082
4083 #if INCLUDE_RTM_OPT
4084 RTMLockingCounters::init();
4085 #endif
4086
4087 call_postVMInitHook(THREAD);
4088 // The Java side of PostVMInitHook.run must deal with all
4089 // exceptions and provide means of diagnosis.
4090 if (HAS_PENDING_EXCEPTION) {
4091 CLEAR_PENDING_EXCEPTION;
4092 }
4093
4094 {
4095 MutexLocker ml(PeriodicTask_lock);
4096 // Make sure the WatcherThread can be started by WatcherThread::start()
4097 // or by dynamic enrollment.
4098 WatcherThread::make_startable();
4099 // Start up the WatcherThread if there are any periodic tasks
4100 // NOTE: All PeriodicTasks should be registered by now. If they
4101 // aren't, late joiners might appear to start slowly (we might
4102 // take a while to process their first tick).
4103 if (PeriodicTask::num_tasks() > 0) {
4104 WatcherThread::start();
4105 }
4106 }
4107
4108 create_vm_timer.end();
4109 #ifdef ASSERT
4110 _vm_complete = true;
4111 #endif
4112
4113 if (DumpSharedSpaces) {
4114 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
4115 ShouldNotReachHere();
4116 }
4117
4118 return JNI_OK;
4119 }
4120
4121 // type for the Agent_OnLoad and JVM_OnLoad entry points
4122 extern "C" {
4123 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
4124 }
4125 // Find a command line agent library and return its entry point for
4126 // -agentlib: -agentpath: -Xrun
4127 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
4128 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
4129 const char *on_load_symbols[],
4130 size_t num_symbol_entries) {
4131 OnLoadEntry_t on_load_entry = NULL;
4132 void *library = NULL;
4133
4134 if (!agent->valid()) {
4135 char buffer[JVM_MAXPATHLEN];
4136 char ebuf[1024] = "";
4137 const char *name = agent->name();
4138 const char *msg = "Could not find agent library ";
4139
4140 // First check to see if agent is statically linked into executable
4141 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
4142 library = agent->os_lib();
4143 } else if (agent->is_absolute_path()) {
4144 library = os::dll_load(name, ebuf, sizeof ebuf);
4145 if (library == NULL) {
4146 const char *sub_msg = " in absolute path, with error: ";
4147 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4148 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4149 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4150 // If we can't find the agent, exit.
4151 vm_exit_during_initialization(buf, NULL);
4152 FREE_C_HEAP_ARRAY(char, buf);
4153 }
4154 } else {
4155 // Try to load the agent from the standard dll directory
4156 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4157 name)) {
4158 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4159 }
4160 if (library == NULL) { // Try the library path directory.
4161 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4162 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4163 }
4164 if (library == NULL) {
4165 const char *sub_msg = " on the library path, with error: ";
4166 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4167
4168 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4169 strlen(ebuf) + strlen(sub_msg2) + 1;
4170 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4171 if (!agent->is_instrument_lib()) {
4172 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4173 } else {
4174 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4175 }
4176 // If we can't find the agent, exit.
4177 vm_exit_during_initialization(buf, NULL);
4178 FREE_C_HEAP_ARRAY(char, buf);
4179 }
4180 }
4181 }
4182 agent->set_os_lib(library);
4183 agent->set_valid();
4184 }
4185
4186 // Find the OnLoad function.
4187 on_load_entry =
4188 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4189 false,
4190 on_load_symbols,
4191 num_symbol_entries));
4192 return on_load_entry;
4193 }
4194
4195 // Find the JVM_OnLoad entry point
4196 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4197 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4198 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4199 }
4200
4201 // Find the Agent_OnLoad entry point
4202 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4203 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4204 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4205 }
4206
4207 // For backwards compatibility with -Xrun
4208 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4209 // treated like -agentpath:
4210 // Must be called before agent libraries are created
4211 void Threads::convert_vm_init_libraries_to_agents() {
4212 AgentLibrary* agent;
4213 AgentLibrary* next;
4214
4215 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4216 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4217 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4218
4219 // If there is an JVM_OnLoad function it will get called later,
4220 // otherwise see if there is an Agent_OnLoad
4221 if (on_load_entry == NULL) {
4222 on_load_entry = lookup_agent_on_load(agent);
4223 if (on_load_entry != NULL) {
4224 // switch it to the agent list -- so that Agent_OnLoad will be called,
4225 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4226 Arguments::convert_library_to_agent(agent);
4227 } else {
4228 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4229 }
4230 }
4231 }
4232 }
4233
4234 // Create agents for -agentlib: -agentpath: and converted -Xrun
4235 // Invokes Agent_OnLoad
4236 // Called very early -- before JavaThreads exist
4237 void Threads::create_vm_init_agents() {
4238 extern struct JavaVM_ main_vm;
4239 AgentLibrary* agent;
4240
4241 JvmtiExport::enter_onload_phase();
4242
4243 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4244 // CDS dumping does not support native JVMTI agent.
4245 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
4246 if (Arguments::is_dumping_archive()) {
4247 if(!agent->is_instrument_lib()) {
4248 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
4249 } else if (!AllowArchivingWithJavaAgent) {
4250 vm_exit_during_cds_dumping(
4251 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
4252 }
4253 }
4254
4255 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4256
4257 if (on_load_entry != NULL) {
4258 // Invoke the Agent_OnLoad function
4259 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4260 if (err != JNI_OK) {
4261 vm_exit_during_initialization("agent library failed to init", agent->name());
4262 }
4263 } else {
4264 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4265 }
4266 }
4267
4268 JvmtiExport::enter_primordial_phase();
4269 }
4270
4271 extern "C" {
4272 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4273 }
4274
4275 void Threads::shutdown_vm_agents() {
4276 // Send any Agent_OnUnload notifications
4277 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4278 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4279 extern struct JavaVM_ main_vm;
4280 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4281
4282 // Find the Agent_OnUnload function.
4283 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4284 os::find_agent_function(agent,
4285 false,
4286 on_unload_symbols,
4287 num_symbol_entries));
4288
4289 // Invoke the Agent_OnUnload function
4290 if (unload_entry != NULL) {
4291 JavaThread* thread = JavaThread::current();
4292 ThreadToNativeFromVM ttn(thread);
4293 HandleMark hm(thread);
4294 (*unload_entry)(&main_vm);
4295 }
4296 }
4297 }
4298
4299 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4300 // Invokes JVM_OnLoad
4301 void Threads::create_vm_init_libraries() {
4302 extern struct JavaVM_ main_vm;
4303 AgentLibrary* agent;
4304
4305 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4306 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4307
4308 if (on_load_entry != NULL) {
4309 // Invoke the JVM_OnLoad function
4310 JavaThread* thread = JavaThread::current();
4311 ThreadToNativeFromVM ttn(thread);
4312 HandleMark hm(thread);
4313 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4314 if (err != JNI_OK) {
4315 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4316 }
4317 } else {
4318 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4319 }
4320 }
4321 }
4322
4323
4324 // Last thread running calls java.lang.Shutdown.shutdown()
4325 void JavaThread::invoke_shutdown_hooks() {
4326 HandleMark hm(this);
4327
4328 // We could get here with a pending exception, if so clear it now.
4329 if (this->has_pending_exception()) {
4330 this->clear_pending_exception();
4331 }
4332
4333 EXCEPTION_MARK;
4334 Klass* shutdown_klass =
4335 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4336 THREAD);
4337 if (shutdown_klass != NULL) {
4338 // SystemDictionary::resolve_or_null will return null if there was
4339 // an exception. If we cannot load the Shutdown class, just don't
4340 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4341 // won't be run. Note that if a shutdown hook was registered,
4342 // the Shutdown class would have already been loaded
4343 // (Runtime.addShutdownHook will load it).
4344 JavaValue result(T_VOID);
4345 JavaCalls::call_static(&result,
4346 shutdown_klass,
4347 vmSymbols::shutdown_name(),
4348 vmSymbols::void_method_signature(),
4349 THREAD);
4350 }
4351 CLEAR_PENDING_EXCEPTION;
4352 }
4353
4354 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4355 // the program falls off the end of main(). Another VM exit path is through
4356 // vm_exit() when the program calls System.exit() to return a value or when
4357 // there is a serious error in VM. The two shutdown paths are not exactly
4358 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4359 // and VM_Exit op at VM level.
4360 //
4361 // Shutdown sequence:
4362 // + Shutdown native memory tracking if it is on
4363 // + Wait until we are the last non-daemon thread to execute
4364 // <-- every thing is still working at this moment -->
4365 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4366 // shutdown hooks
4367 // + Call before_exit(), prepare for VM exit
4368 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4369 // currently the only user of this mechanism is File.deleteOnExit())
4370 // > stop StatSampler, watcher thread,
4371 // post thread end and vm death events to JVMTI,
4372 // stop signal thread
4373 // + Call JavaThread::exit(), it will:
4374 // > release JNI handle blocks, remove stack guard pages
4375 // > remove this thread from Threads list
4376 // <-- no more Java code from this thread after this point -->
4377 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4378 // the compiler threads at safepoint
4379 // <-- do not use anything that could get blocked by Safepoint -->
4380 // + Disable tracing at JNI/JVM barriers
4381 // + Set _vm_exited flag for threads that are still running native code
4382 // + Call exit_globals()
4383 // > deletes tty
4384 // > deletes PerfMemory resources
4385 // + Delete this thread
4386 // + Return to caller
4387
4388 bool Threads::destroy_vm() {
4389 JavaThread* thread = JavaThread::current();
4390
4391 #ifdef ASSERT
4392 _vm_complete = false;
4393 #endif
4394 // Wait until we are the last non-daemon thread to execute
4395 { MonitorLocker nu(Threads_lock);
4396 while (Threads::number_of_non_daemon_threads() > 1)
4397 // This wait should make safepoint checks, wait without a timeout,
4398 // and wait as a suspend-equivalent condition.
4399 nu.wait(0, Mutex::_as_suspend_equivalent_flag);
4400 }
4401
4402 EventShutdown e;
4403 if (e.should_commit()) {
4404 e.set_reason("No remaining non-daemon Java threads");
4405 e.commit();
4406 }
4407
4408 // Hang forever on exit if we are reporting an error.
4409 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4410 os::infinite_sleep();
4411 }
4412 os::wait_for_keypress_at_exit();
4413
4414 // run Java level shutdown hooks
4415 thread->invoke_shutdown_hooks();
4416
4417 before_exit(thread);
4418
4419 thread->exit(true);
4420
4421 // Stop VM thread.
4422 {
4423 // 4945125 The vm thread comes to a safepoint during exit.
4424 // GC vm_operations can get caught at the safepoint, and the
4425 // heap is unparseable if they are caught. Grab the Heap_lock
4426 // to prevent this. The GC vm_operations will not be able to
4427 // queue until after the vm thread is dead. After this point,
4428 // we'll never emerge out of the safepoint before the VM exits.
4429
4430 MutexLocker ml(Heap_lock, Mutex::_no_safepoint_check_flag);
4431
4432 VMThread::wait_for_vm_thread_exit();
4433 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4434 VMThread::destroy();
4435 }
4436
4437 // Now, all Java threads are gone except daemon threads. Daemon threads
4438 // running Java code or in VM are stopped by the Safepoint. However,
4439 // daemon threads executing native code are still running. But they
4440 // will be stopped at native=>Java/VM barriers. Note that we can't
4441 // simply kill or suspend them, as it is inherently deadlock-prone.
4442
4443 VM_Exit::set_vm_exited();
4444
4445 // Clean up ideal graph printers after the VMThread has started
4446 // the final safepoint which will block all the Compiler threads.
4447 // Note that this Thread has already logically exited so the
4448 // clean_up() function's use of a JavaThreadIteratorWithHandle
4449 // would be a problem except set_vm_exited() has remembered the
4450 // shutdown thread which is granted a policy exception.
4451 #if defined(COMPILER2) && !defined(PRODUCT)
4452 IdealGraphPrinter::clean_up();
4453 #endif
4454
4455 notify_vm_shutdown();
4456
4457 // exit_globals() will delete tty
4458 exit_globals();
4459
4460 // We are after VM_Exit::set_vm_exited() so we can't call
4461 // thread->smr_delete() or we will block on the Threads_lock.
4462 // Deleting the shutdown thread here is safe because another
4463 // JavaThread cannot have an active ThreadsListHandle for
4464 // this JavaThread.
4465 delete thread;
4466
4467 #if INCLUDE_JVMCI
4468 if (JVMCICounterSize > 0) {
4469 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4470 }
4471 #endif
4472
4473 LogConfiguration::finalize();
4474
4475 return true;
4476 }
4477
4478
4479 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4480 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4481 return is_supported_jni_version(version);
4482 }
4483
4484
4485 jboolean Threads::is_supported_jni_version(jint version) {
4486 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4487 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4488 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4489 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4490 if (version == JNI_VERSION_9) return JNI_TRUE;
4491 if (version == JNI_VERSION_10) return JNI_TRUE;
4492 return JNI_FALSE;
4493 }
4494
4495
4496 void Threads::add(JavaThread* p, bool force_daemon) {
4497 // The threads lock must be owned at this point
4498 assert(Threads_lock->owned_by_self(), "must have threads lock");
4499
4500 BarrierSet::barrier_set()->on_thread_attach(p);
4501
4502 // Once a JavaThread is added to the Threads list, smr_delete() has
4503 // to be used to delete it. Otherwise we can just delete it directly.
4504 p->set_on_thread_list();
4505
4506 _number_of_threads++;
4507 oop threadObj = p->threadObj();
4508 bool daemon = true;
4509 // Bootstrapping problem: threadObj can be null for initial
4510 // JavaThread (or for threads attached via JNI)
4511 if ((!force_daemon) && !is_daemon((threadObj))) {
4512 _number_of_non_daemon_threads++;
4513 daemon = false;
4514 }
4515
4516 ThreadService::add_thread(p, daemon);
4517
4518 // Maintain fast thread list
4519 ThreadsSMRSupport::add_thread(p);
4520
4521 // Possible GC point.
4522 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4523 }
4524
4525 void Threads::remove(JavaThread* p, bool is_daemon) {
4526
4527 // Reclaim the ObjectMonitors from the om_in_use_list and om_free_list of the moribund thread.
4528 ObjectSynchronizer::om_flush(p);
4529
4530 // Extra scope needed for Thread_lock, so we can check
4531 // that we do not remove thread without safepoint code notice
4532 { MonitorLocker ml(Threads_lock);
4533
4534 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4535
4536 // Maintain fast thread list
4537 ThreadsSMRSupport::remove_thread(p);
4538
4539 _number_of_threads--;
4540 if (!is_daemon) {
4541 _number_of_non_daemon_threads--;
4542
4543 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4544 // on destroy_vm will wake up.
4545 if (number_of_non_daemon_threads() == 1) {
4546 ml.notify_all();
4547 }
4548 }
4549 ThreadService::remove_thread(p, is_daemon);
4550
4551 // Make sure that safepoint code disregard this thread. This is needed since
4552 // the thread might mess around with locks after this point. This can cause it
4553 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4554 // of this thread since it is removed from the queue.
4555 p->set_terminated_value();
4556 } // unlock Threads_lock
4557
4558 // Since Events::log uses a lock, we grab it outside the Threads_lock
4559 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4560 }
4561
4562 // Operations on the Threads list for GC. These are not explicitly locked,
4563 // but the garbage collector must provide a safe context for them to run.
4564 // In particular, these things should never be called when the Threads_lock
4565 // is held by some other thread. (Note: the Safepoint abstraction also
4566 // uses the Threads_lock to guarantee this property. It also makes sure that
4567 // all threads gets blocked when exiting or starting).
4568
4569 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4570 ALL_JAVA_THREADS(p) {
4571 p->oops_do(f, cf);
4572 }
4573 VMThread::vm_thread()->oops_do(f, cf);
4574 }
4575
4576 void Threads::change_thread_claim_token() {
4577 if (++_thread_claim_token == 0) {
4578 // On overflow of the token counter, there is a risk of future
4579 // collisions between a new global token value and a stale token
4580 // for a thread, because not all iterations visit all threads.
4581 // (Though it's pretty much a theoretical concern for non-trivial
4582 // token counter sizes.) To deal with the possibility, reset all
4583 // the thread tokens to zero on global token overflow.
4584 struct ResetClaims : public ThreadClosure {
4585 virtual void do_thread(Thread* t) {
4586 t->claim_threads_do(false, 0);
4587 }
4588 } reset_claims;
4589 Threads::threads_do(&reset_claims);
4590 // On overflow, update the global token to non-zero, to
4591 // avoid the special "never claimed" initial thread value.
4592 _thread_claim_token = 1;
4593 }
4594 }
4595
4596 #ifdef ASSERT
4597 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
4598 const uintx token = t->threads_do_token();
4599 assert(token == expected,
4600 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
4601 UINTX_FORMAT, kind, p2i(t), token, expected);
4602 }
4603
4604 void Threads::assert_all_threads_claimed() {
4605 ALL_JAVA_THREADS(p) {
4606 assert_thread_claimed("Thread", p, _thread_claim_token);
4607 }
4608 assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token);
4609 }
4610 #endif // ASSERT
4611
4612 class ParallelOopsDoThreadClosure : public ThreadClosure {
4613 private:
4614 OopClosure* _f;
4615 CodeBlobClosure* _cf;
4616 public:
4617 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4618 void do_thread(Thread* t) {
4619 t->oops_do(_f, _cf);
4620 }
4621 };
4622
4623 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4624 ParallelOopsDoThreadClosure tc(f, cf);
4625 possibly_parallel_threads_do(is_par, &tc);
4626 }
4627
4628 void Threads::nmethods_do(CodeBlobClosure* cf) {
4629 ALL_JAVA_THREADS(p) {
4630 // This is used by the code cache sweeper to mark nmethods that are active
4631 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4632 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4633 if(!p->is_Code_cache_sweeper_thread()) {
4634 p->nmethods_do(cf);
4635 }
4636 }
4637 }
4638
4639 void Threads::metadata_do(MetadataClosure* f) {
4640 ALL_JAVA_THREADS(p) {
4641 p->metadata_do(f);
4642 }
4643 }
4644
4645 class ThreadHandlesClosure : public ThreadClosure {
4646 void (*_f)(Metadata*);
4647 public:
4648 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4649 virtual void do_thread(Thread* thread) {
4650 thread->metadata_handles_do(_f);
4651 }
4652 };
4653
4654 void Threads::metadata_handles_do(void f(Metadata*)) {
4655 // Only walk the Handles in Thread.
4656 ThreadHandlesClosure handles_closure(f);
4657 threads_do(&handles_closure);
4658 }
4659
4660 // Get count Java threads that are waiting to enter the specified monitor.
4661 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4662 int count,
4663 address monitor) {
4664 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4665
4666 int i = 0;
4667 DO_JAVA_THREADS(t_list, p) {
4668 if (!p->can_call_java()) continue;
4669
4670 address pending = (address)p->current_pending_monitor();
4671 if (pending == monitor) { // found a match
4672 if (i < count) result->append(p); // save the first count matches
4673 i++;
4674 }
4675 }
4676
4677 return result;
4678 }
4679
4680
4681 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4682 address owner) {
4683 // NULL owner means not locked so we can skip the search
4684 if (owner == NULL) return NULL;
4685
4686 DO_JAVA_THREADS(t_list, p) {
4687 // first, see if owner is the address of a Java thread
4688 if (owner == (address)p) return p;
4689 }
4690
4691 // Cannot assert on lack of success here since this function may be
4692 // used by code that is trying to report useful problem information
4693 // like deadlock detection.
4694 if (UseHeavyMonitors) return NULL;
4695
4696 // If we didn't find a matching Java thread and we didn't force use of
4697 // heavyweight monitors, then the owner is the stack address of the
4698 // Lock Word in the owning Java thread's stack.
4699 //
4700 JavaThread* the_owner = NULL;
4701 DO_JAVA_THREADS(t_list, q) {
4702 if (q->is_lock_owned(owner)) {
4703 the_owner = q;
4704 break;
4705 }
4706 }
4707
4708 // cannot assert on lack of success here; see above comment
4709 return the_owner;
4710 }
4711
4712 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4713 void Threads::print_on(outputStream* st, bool print_stacks,
4714 bool internal_format, bool print_concurrent_locks,
4715 bool print_extended_info) {
4716 char buf[32];
4717 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4718
4719 st->print_cr("Full thread dump %s (%s %s):",
4720 VM_Version::vm_name(),
4721 VM_Version::vm_release(),
4722 VM_Version::vm_info_string());
4723 st->cr();
4724
4725 #if INCLUDE_SERVICES
4726 // Dump concurrent locks
4727 ConcurrentLocksDump concurrent_locks;
4728 if (print_concurrent_locks) {
4729 concurrent_locks.dump_at_safepoint();
4730 }
4731 #endif // INCLUDE_SERVICES
4732
4733 ThreadsSMRSupport::print_info_on(st);
4734 st->cr();
4735
4736 ALL_JAVA_THREADS(p) {
4737 ResourceMark rm;
4738 p->print_on(st, print_extended_info);
4739 if (print_stacks) {
4740 if (internal_format) {
4741 p->trace_stack();
4742 } else {
4743 p->print_stack_on(st);
4744 }
4745 }
4746 st->cr();
4747 #if INCLUDE_SERVICES
4748 if (print_concurrent_locks) {
4749 concurrent_locks.print_locks_on(p, st);
4750 }
4751 #endif // INCLUDE_SERVICES
4752 }
4753
4754 VMThread::vm_thread()->print_on(st);
4755 st->cr();
4756 Universe::heap()->print_gc_threads_on(st);
4757 WatcherThread* wt = WatcherThread::watcher_thread();
4758 if (wt != NULL) {
4759 wt->print_on(st);
4760 st->cr();
4761 }
4762
4763 st->flush();
4764 }
4765
4766 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4767 int buflen, bool* found_current) {
4768 if (this_thread != NULL) {
4769 bool is_current = (current == this_thread);
4770 *found_current = *found_current || is_current;
4771 st->print("%s", is_current ? "=>" : " ");
4772
4773 st->print(PTR_FORMAT, p2i(this_thread));
4774 st->print(" ");
4775 this_thread->print_on_error(st, buf, buflen);
4776 st->cr();
4777 }
4778 }
4779
4780 class PrintOnErrorClosure : public ThreadClosure {
4781 outputStream* _st;
4782 Thread* _current;
4783 char* _buf;
4784 int _buflen;
4785 bool* _found_current;
4786 public:
4787 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4788 int buflen, bool* found_current) :
4789 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4790
4791 virtual void do_thread(Thread* thread) {
4792 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4793 }
4794 };
4795
4796 // Threads::print_on_error() is called by fatal error handler. It's possible
4797 // that VM is not at safepoint and/or current thread is inside signal handler.
4798 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4799 // memory (even in resource area), it might deadlock the error handler.
4800 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4801 int buflen) {
4802 ThreadsSMRSupport::print_info_on(st);
4803 st->cr();
4804
4805 bool found_current = false;
4806 st->print_cr("Java Threads: ( => current thread )");
4807 ALL_JAVA_THREADS(thread) {
4808 print_on_error(thread, st, current, buf, buflen, &found_current);
4809 }
4810 st->cr();
4811
4812 st->print_cr("Other Threads:");
4813 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4814 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4815
4816 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4817 Universe::heap()->gc_threads_do(&print_closure);
4818
4819 if (!found_current) {
4820 st->cr();
4821 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4822 current->print_on_error(st, buf, buflen);
4823 st->cr();
4824 }
4825 st->cr();
4826
4827 st->print_cr("Threads with active compile tasks:");
4828 print_threads_compiling(st, buf, buflen);
4829 }
4830
4831 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
4832 ALL_JAVA_THREADS(thread) {
4833 if (thread->is_Compiler_thread()) {
4834 CompilerThread* ct = (CompilerThread*) thread;
4835
4836 // Keep task in local variable for NULL check.
4837 // ct->_task might be set to NULL by concurring compiler thread
4838 // because it completed the compilation. The task is never freed,
4839 // though, just returned to a free list.
4840 CompileTask* task = ct->task();
4841 if (task != NULL) {
4842 thread->print_name_on_error(st, buf, buflen);
4843 st->print(" ");
4844 task->print(st, NULL, short_form, true);
4845 }
4846 }
4847 }
4848 }
4849
4850
4851 // Internal SpinLock and Mutex
4852 // Based on ParkEvent
4853
4854 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4855 //
4856 // We employ SpinLocks _only for low-contention, fixed-length
4857 // short-duration critical sections where we're concerned
4858 // about native mutex_t or HotSpot Mutex:: latency.
4859 // The mux construct provides a spin-then-block mutual exclusion
4860 // mechanism.
4861 //
4862 // Testing has shown that contention on the ListLock guarding gFreeList
4863 // is common. If we implement ListLock as a simple SpinLock it's common
4864 // for the JVM to devolve to yielding with little progress. This is true
4865 // despite the fact that the critical sections protected by ListLock are
4866 // extremely short.
4867 //
4868 // TODO-FIXME: ListLock should be of type SpinLock.
4869 // We should make this a 1st-class type, integrated into the lock
4870 // hierarchy as leaf-locks. Critically, the SpinLock structure
4871 // should have sufficient padding to avoid false-sharing and excessive
4872 // cache-coherency traffic.
4873
4874
4875 typedef volatile int SpinLockT;
4876
4877 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4878 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4879 return; // normal fast-path return
4880 }
4881
4882 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4883 int ctr = 0;
4884 int Yields = 0;
4885 for (;;) {
4886 while (*adr != 0) {
4887 ++ctr;
4888 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4889 if (Yields > 5) {
4890 os::naked_short_sleep(1);
4891 } else {
4892 os::naked_yield();
4893 ++Yields;
4894 }
4895 } else {
4896 SpinPause();
4897 }
4898 }
4899 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4900 }
4901 }
4902
4903 void Thread::SpinRelease(volatile int * adr) {
4904 assert(*adr != 0, "invariant");
4905 OrderAccess::fence(); // guarantee at least release consistency.
4906 // Roach-motel semantics.
4907 // It's safe if subsequent LDs and STs float "up" into the critical section,
4908 // but prior LDs and STs within the critical section can't be allowed
4909 // to reorder or float past the ST that releases the lock.
4910 // Loads and stores in the critical section - which appear in program
4911 // order before the store that releases the lock - must also appear
4912 // before the store that releases the lock in memory visibility order.
4913 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4914 // the ST of 0 into the lock-word which releases the lock, so fence
4915 // more than covers this on all platforms.
4916 *adr = 0;
4917 }
4918
4919 // muxAcquire and muxRelease:
4920 //
4921 // * muxAcquire and muxRelease support a single-word lock-word construct.
4922 // The LSB of the word is set IFF the lock is held.
4923 // The remainder of the word points to the head of a singly-linked list
4924 // of threads blocked on the lock.
4925 //
4926 // * The current implementation of muxAcquire-muxRelease uses its own
4927 // dedicated Thread._MuxEvent instance. If we're interested in
4928 // minimizing the peak number of extant ParkEvent instances then
4929 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4930 // as certain invariants were satisfied. Specifically, care would need
4931 // to be taken with regards to consuming unpark() "permits".
4932 // A safe rule of thumb is that a thread would never call muxAcquire()
4933 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4934 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4935 // consume an unpark() permit intended for monitorenter, for instance.
4936 // One way around this would be to widen the restricted-range semaphore
4937 // implemented in park(). Another alternative would be to provide
4938 // multiple instances of the PlatformEvent() for each thread. One
4939 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4940 //
4941 // * Usage:
4942 // -- Only as leaf locks
4943 // -- for short-term locking only as muxAcquire does not perform
4944 // thread state transitions.
4945 //
4946 // Alternatives:
4947 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4948 // but with parking or spin-then-park instead of pure spinning.
4949 // * Use Taura-Oyama-Yonenzawa locks.
4950 // * It's possible to construct a 1-0 lock if we encode the lockword as
4951 // (List,LockByte). Acquire will CAS the full lockword while Release
4952 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4953 // acquiring threads use timers (ParkTimed) to detect and recover from
4954 // the stranding window. Thread/Node structures must be aligned on 256-byte
4955 // boundaries by using placement-new.
4956 // * Augment MCS with advisory back-link fields maintained with CAS().
4957 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4958 // The validity of the backlinks must be ratified before we trust the value.
4959 // If the backlinks are invalid the exiting thread must back-track through the
4960 // the forward links, which are always trustworthy.
4961 // * Add a successor indication. The LockWord is currently encoded as
4962 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4963 // to provide the usual futile-wakeup optimization.
4964 // See RTStt for details.
4965 //
4966
4967
4968 const intptr_t LOCKBIT = 1;
4969
4970 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4971 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4972 if (w == 0) return;
4973 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4974 return;
4975 }
4976
4977 ParkEvent * const Self = Thread::current()->_MuxEvent;
4978 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4979 for (;;) {
4980 int its = (os::is_MP() ? 100 : 0) + 1;
4981
4982 // Optional spin phase: spin-then-park strategy
4983 while (--its >= 0) {
4984 w = *Lock;
4985 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4986 return;
4987 }
4988 }
4989
4990 Self->reset();
4991 Self->OnList = intptr_t(Lock);
4992 // The following fence() isn't _strictly necessary as the subsequent
4993 // CAS() both serializes execution and ratifies the fetched *Lock value.
4994 OrderAccess::fence();
4995 for (;;) {
4996 w = *Lock;
4997 if ((w & LOCKBIT) == 0) {
4998 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4999 Self->OnList = 0; // hygiene - allows stronger asserts
5000 return;
5001 }
5002 continue; // Interference -- *Lock changed -- Just retry
5003 }
5004 assert(w & LOCKBIT, "invariant");
5005 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
5006 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
5007 }
5008
5009 while (Self->OnList != 0) {
5010 Self->park();
5011 }
5012 }
5013 }
5014
5015 // Release() must extract a successor from the list and then wake that thread.
5016 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
5017 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
5018 // Release() would :
5019 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
5020 // (B) Extract a successor from the private list "in-hand"
5021 // (C) attempt to CAS() the residual back into *Lock over null.
5022 // If there were any newly arrived threads and the CAS() would fail.
5023 // In that case Release() would detach the RATs, re-merge the list in-hand
5024 // with the RATs and repeat as needed. Alternately, Release() might
5025 // detach and extract a successor, but then pass the residual list to the wakee.
5026 // The wakee would be responsible for reattaching and remerging before it
5027 // competed for the lock.
5028 //
5029 // Both "pop" and DMR are immune from ABA corruption -- there can be
5030 // multiple concurrent pushers, but only one popper or detacher.
5031 // This implementation pops from the head of the list. This is unfair,
5032 // but tends to provide excellent throughput as hot threads remain hot.
5033 // (We wake recently run threads first).
5034 //
5035 // All paths through muxRelease() will execute a CAS.
5036 // Release consistency -- We depend on the CAS in muxRelease() to provide full
5037 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
5038 // executed within the critical section are complete and globally visible before the
5039 // store (CAS) to the lock-word that releases the lock becomes globally visible.
5040 void Thread::muxRelease(volatile intptr_t * Lock) {
5041 for (;;) {
5042 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
5043 assert(w & LOCKBIT, "invariant");
5044 if (w == LOCKBIT) return;
5045 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
5046 assert(List != NULL, "invariant");
5047 assert(List->OnList == intptr_t(Lock), "invariant");
5048 ParkEvent * const nxt = List->ListNext;
5049 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5050
5051 // The following CAS() releases the lock and pops the head element.
5052 // The CAS() also ratifies the previously fetched lock-word value.
5053 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
5054 continue;
5055 }
5056 List->OnList = 0;
5057 OrderAccess::fence();
5058 List->unpark();
5059 return;
5060 }
5061 }
5062
5063
5064 void Threads::verify() {
5065 ALL_JAVA_THREADS(p) {
5066 p->verify();
5067 }
5068 VMThread* thread = VMThread::vm_thread();
5069 if (thread != NULL) thread->verify();
5070 }
--- EOF ---