1 /*
2 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/moduleEntry.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "classfile/vmSymbols.hpp"
32 #include "code/codeCache.hpp"
33 #include "code/scopeDesc.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "compiler/compileTask.hpp"
36 #include "gc/shared/barrierSet.hpp"
37 #include "gc/shared/gcId.hpp"
38 #include "gc/shared/gcLocker.inline.hpp"
39 #include "gc/shared/workgroup.hpp"
40 #include "interpreter/interpreter.hpp"
41 #include "interpreter/linkResolver.hpp"
42 #include "interpreter/oopMapCache.hpp"
43 #include "jfr/jfrEvents.hpp"
44 #include "jvmtifiles/jvmtiEnv.hpp"
45 #include "logging/log.hpp"
46 #include "logging/logConfiguration.hpp"
47 #include "logging/logStream.hpp"
48 #include "memory/allocation.inline.hpp"
49 #include "memory/metaspaceShared.hpp"
50 #include "memory/oopFactory.hpp"
51 #include "memory/resourceArea.hpp"
52 #include "memory/universe.hpp"
53 #include "oops/access.inline.hpp"
54 #include "oops/instanceKlass.hpp"
55 #include "oops/objArrayOop.hpp"
56 #include "oops/oop.inline.hpp"
57 #include "oops/symbol.hpp"
58 #include "oops/typeArrayOop.inline.hpp"
59 #include "oops/verifyOopClosure.hpp"
60 #include "prims/jvm_misc.hpp"
61 #include "prims/jvmtiExport.hpp"
62 #include "prims/jvmtiThreadState.hpp"
63 #include "runtime/arguments.hpp"
64 #include "runtime/atomic.hpp"
65 #include "runtime/biasedLocking.hpp"
66 #include "runtime/fieldDescriptor.inline.hpp"
67 #include "runtime/flags/jvmFlagConstraintList.hpp"
68 #include "runtime/flags/jvmFlagRangeList.hpp"
69 #include "runtime/flags/jvmFlagWriteableList.hpp"
70 #include "runtime/deoptimization.hpp"
71 #include "runtime/frame.inline.hpp"
72 #include "runtime/handles.inline.hpp"
73 #include "runtime/handshake.hpp"
74 #include "runtime/init.hpp"
75 #include "runtime/interfaceSupport.inline.hpp"
76 #include "runtime/java.hpp"
77 #include "runtime/javaCalls.hpp"
78 #include "runtime/jniHandles.inline.hpp"
79 #include "runtime/jniPeriodicChecker.hpp"
80 #include "runtime/memprofiler.hpp"
81 #include "runtime/mutexLocker.hpp"
82 #include "runtime/objectMonitor.hpp"
83 #include "runtime/orderAccess.hpp"
84 #include "runtime/osThread.hpp"
85 #include "runtime/prefetch.inline.hpp"
86 #include "runtime/safepoint.hpp"
87 #include "runtime/safepointMechanism.inline.hpp"
88 #include "runtime/safepointVerifiers.hpp"
89 #include "runtime/sharedRuntime.hpp"
90 #include "runtime/statSampler.hpp"
91 #include "runtime/stubRoutines.hpp"
92 #include "runtime/sweeper.hpp"
93 #include "runtime/task.hpp"
94 #include "runtime/thread.inline.hpp"
95 #include "runtime/threadCritical.hpp"
96 #include "runtime/threadSMR.inline.hpp"
97 #include "runtime/threadStatisticalInfo.hpp"
98 #include "runtime/timer.hpp"
99 #include "runtime/timerTrace.hpp"
100 #include "runtime/vframe.inline.hpp"
101 #include "runtime/vframeArray.hpp"
102 #include "runtime/vframe_hp.hpp"
103 #include "runtime/vmThread.hpp"
104 #include "runtime/vmOperations.hpp"
105 #include "runtime/vm_version.hpp"
106 #include "services/attachListener.hpp"
107 #include "services/management.hpp"
108 #include "services/memTracker.hpp"
109 #include "services/threadService.hpp"
110 #include "utilities/align.hpp"
111 #include "utilities/copy.hpp"
112 #include "utilities/defaultStream.hpp"
113 #include "utilities/dtrace.hpp"
114 #include "utilities/events.hpp"
115 #include "utilities/macros.hpp"
116 #include "utilities/preserveException.hpp"
117 #include "utilities/singleWriterSynchronizer.hpp"
118 #include "utilities/vmError.hpp"
119 #if INCLUDE_JVMCI
120 #include "jvmci/jvmci.hpp"
121 #include "jvmci/jvmciEnv.hpp"
122 #endif
123 #ifdef COMPILER1
124 #include "c1/c1_Compiler.hpp"
125 #endif
126 #ifdef COMPILER2
127 #include "opto/c2compiler.hpp"
128 #include "opto/idealGraphPrinter.hpp"
129 #endif
130 #if INCLUDE_RTM_OPT
131 #include "runtime/rtmLocking.hpp"
132 #endif
133 #if INCLUDE_JFR
134 #include "jfr/jfr.hpp"
135 #endif
136
137 // Initialization after module runtime initialization
138 void universe_post_module_init(); // must happen after call_initPhase2
139
140 #ifdef DTRACE_ENABLED
141
142 // Only bother with this argument setup if dtrace is available
143
144 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
145 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
146
147 #define DTRACE_THREAD_PROBE(probe, javathread) \
148 { \
149 ResourceMark rm(this); \
150 int len = 0; \
151 const char* name = (javathread)->get_thread_name(); \
152 len = strlen(name); \
153 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
154 (char *) name, len, \
155 java_lang_Thread::thread_id((javathread)->threadObj()), \
156 (uintptr_t) (javathread)->osthread()->thread_id(), \
157 java_lang_Thread::is_daemon((javathread)->threadObj())); \
158 }
159
160 #else // ndef DTRACE_ENABLED
161
162 #define DTRACE_THREAD_PROBE(probe, javathread)
163
164 #endif // ndef DTRACE_ENABLED
165
166 #ifndef USE_LIBRARY_BASED_TLS_ONLY
167 // Current thread is maintained as a thread-local variable
168 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
169 #endif
170
171 // ======= Thread ========
172 // Support for forcing alignment of thread objects for biased locking
173 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
174 if (UseBiasedLocking) {
175 const int alignment = markOopDesc::biased_lock_alignment;
176 size_t aligned_size = size + (alignment - sizeof(intptr_t));
177 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
178 : AllocateHeap(aligned_size, flags, CURRENT_PC,
179 AllocFailStrategy::RETURN_NULL);
180 void* aligned_addr = align_up(real_malloc_addr, alignment);
181 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
182 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
183 "JavaThread alignment code overflowed allocated storage");
184 if (aligned_addr != real_malloc_addr) {
185 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
186 p2i(real_malloc_addr),
187 p2i(aligned_addr));
188 }
189 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
190 return aligned_addr;
191 } else {
192 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
193 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
194 }
195 }
196
197 void Thread::operator delete(void* p) {
198 if (UseBiasedLocking) {
199 FreeHeap(((Thread*) p)->_real_malloc_address);
200 } else {
201 FreeHeap(p);
202 }
203 }
204
205 void JavaThread::smr_delete() {
206 if (_on_thread_list) {
207 ThreadsSMRSupport::smr_delete(this);
208 } else {
209 delete this;
210 }
211 }
212
213 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
214 // JavaThread
215
216 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
217
218 Thread::Thread() {
219
220 DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
221
222 // stack and get_thread
223 set_stack_base(NULL);
224 set_stack_size(0);
225 set_self_raw_id(0);
226 set_lgrp_id(-1);
227 DEBUG_ONLY(clear_suspendible_thread();)
228
229 // allocated data structures
230 set_osthread(NULL);
231 set_resource_area(new (mtThread)ResourceArea());
232 DEBUG_ONLY(_current_resource_mark = NULL;)
233 set_handle_area(new (mtThread) HandleArea(NULL));
234 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
235 set_active_handles(NULL);
236 set_free_handle_block(NULL);
237 set_last_handle_mark(NULL);
238 DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
239
240 // 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 debug_only(_allow_allocation_count = 0;)
253 NOT_PRODUCT(_allow_safepoint_count = 0;)
254 NOT_PRODUCT(_skip_gcalot = false;)
255 _jvmti_env_iteration_count = 0;
256 set_allocated_bytes(0);
257 _vm_operation_started_count = 0;
258 _vm_operation_completed_count = 0;
259 _current_pending_monitor = NULL;
260 _current_pending_monitor_is_from_java = true;
261 _current_waiting_monitor = NULL;
262 _num_nested_signal = 0;
263 omFreeList = NULL;
264 omFreeCount = 0;
265 omFreeProvision = 32;
266 omInUseList = NULL;
267 omInUseCount = 0;
268
269 #ifdef ASSERT
270 _visited_for_critical_count = false;
271 #endif
272
273 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
274 Monitor::_safepoint_check_sometimes);
275 _suspend_flags = 0;
276
277 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
278 _hashStateX = os::random();
279 _hashStateY = 842502087;
280 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
281 _hashStateW = 273326509;
282
283 _OnTrap = 0;
284 _Stalled = 0;
285 _TypeTag = 0x2BAD;
286
287 // Many of the following fields are effectively final - immutable
288 // Note that nascent threads can't use the Native Monitor-Mutex
289 // construct until the _MutexEvent is initialized ...
290 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
291 // we might instead use a stack of ParkEvents that we could provision on-demand.
292 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
293 // and ::Release()
294 _ParkEvent = ParkEvent::Allocate(this);
295 _SleepEvent = ParkEvent::Allocate(this);
296 _MuxEvent = ParkEvent::Allocate(this);
297
298 #ifdef CHECK_UNHANDLED_OOPS
299 if (CheckUnhandledOops) {
300 _unhandled_oops = new UnhandledOops(this);
301 }
302 #endif // CHECK_UNHANDLED_OOPS
303 #ifdef ASSERT
304 if (UseBiasedLocking) {
305 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
306 assert(this == _real_malloc_address ||
307 this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
308 "bug in forced alignment of thread objects");
309 }
310 #endif // ASSERT
311
312 // Notify the barrier set that a thread is being created. The initial
313 // thread is created before the barrier set is available. The call to
314 // BarrierSet::on_thread_create() for this thread is therefore deferred
315 // to BarrierSet::set_barrier_set().
316 BarrierSet* const barrier_set = BarrierSet::barrier_set();
317 if (barrier_set != NULL) {
318 barrier_set->on_thread_create(this);
319 } else {
320 // Only the main thread should be created before the barrier set
321 // and that happens just before Thread::current is set. No other thread
322 // can attach as the VM is not created yet, so they can't execute this code.
323 // If the main thread creates other threads before the barrier set that is an error.
324 assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
325 }
326 }
327
328 void Thread::initialize_thread_current() {
329 #ifndef USE_LIBRARY_BASED_TLS_ONLY
330 assert(_thr_current == NULL, "Thread::current already initialized");
331 _thr_current = this;
332 #endif
333 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
334 ThreadLocalStorage::set_thread(this);
335 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
336 }
337
338 void Thread::clear_thread_current() {
339 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
340 #ifndef USE_LIBRARY_BASED_TLS_ONLY
341 _thr_current = NULL;
342 #endif
343 ThreadLocalStorage::set_thread(NULL);
344 }
345
346 void Thread::record_stack_base_and_size() {
347 // Note: at this point, Thread object is not yet initialized. Do not rely on
348 // any members being initialized. Do not rely on Thread::current() being set.
349 // If possible, refrain from doing anything which may crash or assert since
350 // quite probably those crash dumps will be useless.
351 set_stack_base(os::current_stack_base());
352 set_stack_size(os::current_stack_size());
353
354 #ifdef SOLARIS
355 if (os::is_primordial_thread()) {
356 os::Solaris::correct_stack_boundaries_for_primordial_thread(this);
357 }
358 #endif
359
360 // Set stack limits after thread is initialized.
361 if (is_Java_thread()) {
362 ((JavaThread*) this)->set_stack_overflow_limit();
363 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
364 }
365 }
366
367 #if INCLUDE_NMT
368 void Thread::register_thread_stack_with_NMT() {
369 MemTracker::record_thread_stack(stack_end(), stack_size());
370 }
371 #endif // INCLUDE_NMT
372
373 void Thread::call_run() {
374 DEBUG_ONLY(_run_state = CALL_RUN;)
375
376 // At this point, Thread object should be fully initialized and
377 // Thread::current() should be set.
378
379 assert(Thread::current_or_null() != NULL, "current thread is unset");
380 assert(Thread::current_or_null() == this, "current thread is wrong");
381
382 // Perform common initialization actions
383
384 register_thread_stack_with_NMT();
385
386 JFR_ONLY(Jfr::on_thread_start(this);)
387
388 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
389 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
390 os::current_thread_id(), p2i(stack_base() - stack_size()),
391 p2i(stack_base()), stack_size()/1024);
392
393 // Perform <ChildClass> initialization actions
394 DEBUG_ONLY(_run_state = PRE_RUN;)
395 this->pre_run();
396
397 // Invoke <ChildClass>::run()
398 DEBUG_ONLY(_run_state = RUN;)
399 this->run();
400 // Returned from <ChildClass>::run(). Thread finished.
401
402 // Perform common tear-down actions
403
404 assert(Thread::current_or_null() != NULL, "current thread is unset");
405 assert(Thread::current_or_null() == this, "current thread is wrong");
406
407 // Perform <ChildClass> tear-down actions
408 DEBUG_ONLY(_run_state = POST_RUN;)
409 this->post_run();
410
411 // Note: at this point the thread object may already have deleted itself,
412 // so from here on do not dereference *this*. Not all thread types currently
413 // delete themselves when they terminate. But no thread should ever be deleted
414 // asynchronously with respect to its termination - that is what _run_state can
415 // be used to check.
416
417 assert(Thread::current_or_null() == NULL, "current thread still present");
418 }
419
420 Thread::~Thread() {
421
422 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
423 // get started due to errors etc. Any active thread should at least reach post_run
424 // before it is deleted (usually in post_run()).
425 assert(_run_state == PRE_CALL_RUN ||
426 _run_state == POST_RUN, "Active Thread deleted before post_run(): "
427 "_run_state=%d", (int)_run_state);
428
429 // Notify the barrier set that a thread is being destroyed. Note that a barrier
430 // set might not be available if we encountered errors during bootstrapping.
431 BarrierSet* const barrier_set = BarrierSet::barrier_set();
432 if (barrier_set != NULL) {
433 barrier_set->on_thread_destroy(this);
434 }
435
436 // stack_base can be NULL if the thread is never started or exited before
437 // record_stack_base_and_size called. Although, we would like to ensure
438 // that all started threads do call record_stack_base_and_size(), there is
439 // not proper way to enforce that.
440 #if INCLUDE_NMT
441 if (_stack_base != NULL) {
442 MemTracker::release_thread_stack(stack_end(), stack_size());
443 #ifdef ASSERT
444 set_stack_base(NULL);
445 #endif
446 }
447 #endif // INCLUDE_NMT
448
449 // deallocate data structures
450 delete resource_area();
451 // since the handle marks are using the handle area, we have to deallocated the root
452 // handle mark before deallocating the thread's handle area,
453 assert(last_handle_mark() != NULL, "check we have an element");
454 delete last_handle_mark();
455 assert(last_handle_mark() == NULL, "check we have reached the end");
456
457 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
458 // We NULL out the fields for good hygiene.
459 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
460 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
461 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
462
463 delete handle_area();
464 delete metadata_handles();
465
466 // SR_handler uses this as a termination indicator -
467 // needs to happen before os::free_thread()
468 delete _SR_lock;
469 _SR_lock = NULL;
470
471 // osthread() can be NULL, if creation of thread failed.
472 if (osthread() != NULL) os::free_thread(osthread());
473
474 // Clear Thread::current if thread is deleting itself and it has not
475 // already been done. This must be done before the memory is deallocated.
476 // Needed to ensure JNI correctly detects non-attached threads.
477 if (this == Thread::current_or_null()) {
478 Thread::clear_thread_current();
479 }
480
481 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
482 }
483
484 #ifdef ASSERT
485 // A JavaThread is considered "dangling" if it is not the current
486 // thread, has been added the Threads list, the system is not at a
487 // safepoint and the Thread is not "protected".
488 //
489 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
490 assert(!thread->is_Java_thread() || Thread::current() == thread ||
491 !((JavaThread *) thread)->on_thread_list() ||
492 SafepointSynchronize::is_at_safepoint() ||
493 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
494 "possibility of dangling Thread pointer");
495 }
496 #endif
497
498 ThreadPriority Thread::get_priority(const Thread* const thread) {
499 ThreadPriority priority;
500 // Can return an error!
501 (void)os::get_priority(thread, priority);
502 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
503 return priority;
504 }
505
506 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
507 debug_only(check_for_dangling_thread_pointer(thread);)
508 // Can return an error!
509 (void)os::set_priority(thread, priority);
510 }
511
512
513 void Thread::start(Thread* thread) {
514 // Start is different from resume in that its safety is guaranteed by context or
515 // being called from a Java method synchronized on the Thread object.
516 if (!DisableStartThread) {
517 if (thread->is_Java_thread()) {
518 // Initialize the thread state to RUNNABLE before starting this thread.
519 // Can not set it after the thread started because we do not know the
520 // exact thread state at that time. It could be in MONITOR_WAIT or
521 // in SLEEPING or some other state.
522 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
523 java_lang_Thread::RUNNABLE);
524 }
525 os::start_thread(thread);
526 }
527 }
528
529 // Enqueue a VM_Operation to do the job for us - sometime later
530 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
531 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
532 VMThread::execute(vm_stop);
533 }
534
535
536 // Check if an external suspend request has completed (or has been
537 // cancelled). Returns true if the thread is externally suspended and
538 // false otherwise.
539 //
540 // The bits parameter returns information about the code path through
541 // the routine. Useful for debugging:
542 //
543 // set in is_ext_suspend_completed():
544 // 0x00000001 - routine was entered
545 // 0x00000010 - routine return false at end
546 // 0x00000100 - thread exited (return false)
547 // 0x00000200 - suspend request cancelled (return false)
548 // 0x00000400 - thread suspended (return true)
549 // 0x00001000 - thread is in a suspend equivalent state (return true)
550 // 0x00002000 - thread is native and walkable (return true)
551 // 0x00004000 - thread is native_trans and walkable (needed retry)
552 //
553 // set in wait_for_ext_suspend_completion():
554 // 0x00010000 - routine was entered
555 // 0x00020000 - suspend request cancelled before loop (return false)
556 // 0x00040000 - thread suspended before loop (return true)
557 // 0x00080000 - suspend request cancelled in loop (return false)
558 // 0x00100000 - thread suspended in loop (return true)
559 // 0x00200000 - suspend not completed during retry loop (return false)
560
561 // Helper class for tracing suspend wait debug bits.
562 //
563 // 0x00000100 indicates that the target thread exited before it could
564 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
565 // 0x00080000 each indicate a cancelled suspend request so they don't
566 // count as wait failures either.
567 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
568
569 class TraceSuspendDebugBits : public StackObj {
570 private:
571 JavaThread * jt;
572 bool is_wait;
573 bool called_by_wait; // meaningful when !is_wait
574 uint32_t * bits;
575
576 public:
577 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
578 uint32_t *_bits) {
579 jt = _jt;
580 is_wait = _is_wait;
581 called_by_wait = _called_by_wait;
582 bits = _bits;
583 }
584
585 ~TraceSuspendDebugBits() {
586 if (!is_wait) {
587 #if 1
588 // By default, don't trace bits for is_ext_suspend_completed() calls.
589 // That trace is very chatty.
590 return;
591 #else
592 if (!called_by_wait) {
593 // If tracing for is_ext_suspend_completed() is enabled, then only
594 // trace calls to it from wait_for_ext_suspend_completion()
595 return;
596 }
597 #endif
598 }
599
600 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
601 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
602 MutexLocker ml(Threads_lock); // needed for get_thread_name()
603 ResourceMark rm;
604
605 tty->print_cr(
606 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
607 jt->get_thread_name(), *bits);
608
609 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
610 }
611 }
612 }
613 };
614 #undef DEBUG_FALSE_BITS
615
616
617 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
618 uint32_t *bits) {
619 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
620
621 bool did_trans_retry = false; // only do thread_in_native_trans retry once
622 bool do_trans_retry; // flag to force the retry
623
624 *bits |= 0x00000001;
625
626 do {
627 do_trans_retry = false;
628
629 if (is_exiting()) {
630 // Thread is in the process of exiting. This is always checked
631 // first to reduce the risk of dereferencing a freed JavaThread.
632 *bits |= 0x00000100;
633 return false;
634 }
635
636 if (!is_external_suspend()) {
637 // Suspend request is cancelled. This is always checked before
638 // is_ext_suspended() to reduce the risk of a rogue resume
639 // confusing the thread that made the suspend request.
640 *bits |= 0x00000200;
641 return false;
642 }
643
644 if (is_ext_suspended()) {
645 // thread is suspended
646 *bits |= 0x00000400;
647 return true;
648 }
649
650 // Now that we no longer do hard suspends of threads running
651 // native code, the target thread can be changing thread state
652 // while we are in this routine:
653 //
654 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
655 //
656 // We save a copy of the thread state as observed at this moment
657 // and make our decision about suspend completeness based on the
658 // copy. This closes the race where the thread state is seen as
659 // _thread_in_native_trans in the if-thread_blocked check, but is
660 // seen as _thread_blocked in if-thread_in_native_trans check.
661 JavaThreadState save_state = thread_state();
662
663 if (save_state == _thread_blocked && is_suspend_equivalent()) {
664 // If the thread's state is _thread_blocked and this blocking
665 // condition is known to be equivalent to a suspend, then we can
666 // consider the thread to be externally suspended. This means that
667 // the code that sets _thread_blocked has been modified to do
668 // self-suspension if the blocking condition releases. We also
669 // used to check for CONDVAR_WAIT here, but that is now covered by
670 // the _thread_blocked with self-suspension check.
671 //
672 // Return true since we wouldn't be here unless there was still an
673 // external suspend request.
674 *bits |= 0x00001000;
675 return true;
676 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
677 // Threads running native code will self-suspend on native==>VM/Java
678 // transitions. If its stack is walkable (should always be the case
679 // unless this function is called before the actual java_suspend()
680 // call), then the wait is done.
681 *bits |= 0x00002000;
682 return true;
683 } else if (!called_by_wait && !did_trans_retry &&
684 save_state == _thread_in_native_trans &&
685 frame_anchor()->walkable()) {
686 // The thread is transitioning from thread_in_native to another
687 // thread state. check_safepoint_and_suspend_for_native_trans()
688 // will force the thread to self-suspend. If it hasn't gotten
689 // there yet we may have caught the thread in-between the native
690 // code check above and the self-suspend. Lucky us. If we were
691 // called by wait_for_ext_suspend_completion(), then it
692 // will be doing the retries so we don't have to.
693 //
694 // Since we use the saved thread state in the if-statement above,
695 // there is a chance that the thread has already transitioned to
696 // _thread_blocked by the time we get here. In that case, we will
697 // make a single unnecessary pass through the logic below. This
698 // doesn't hurt anything since we still do the trans retry.
699
700 *bits |= 0x00004000;
701
702 // Once the thread leaves thread_in_native_trans for another
703 // thread state, we break out of this retry loop. We shouldn't
704 // need this flag to prevent us from getting back here, but
705 // sometimes paranoia is good.
706 did_trans_retry = true;
707
708 // We wait for the thread to transition to a more usable state.
709 for (int i = 1; i <= SuspendRetryCount; i++) {
710 // We used to do an "os::yield_all(i)" call here with the intention
711 // that yielding would increase on each retry. However, the parameter
712 // is ignored on Linux which means the yield didn't scale up. Waiting
713 // on the SR_lock below provides a much more predictable scale up for
714 // the delay. It also provides a simple/direct point to check for any
715 // safepoint requests from the VMThread
716
717 // temporarily drops SR_lock while doing wait with safepoint check
718 // (if we're a JavaThread - the WatcherThread can also call this)
719 // and increase delay with each retry
720 if (Thread::current()->is_Java_thread()) {
721 SR_lock()->wait(i * delay);
722 } else {
723 SR_lock()->wait_without_safepoint_check(i * delay);
724 }
725
726 // check the actual thread state instead of what we saved above
727 if (thread_state() != _thread_in_native_trans) {
728 // the thread has transitioned to another thread state so
729 // try all the checks (except this one) one more time.
730 do_trans_retry = true;
731 break;
732 }
733 } // end retry loop
734
735
736 }
737 } while (do_trans_retry);
738
739 *bits |= 0x00000010;
740 return false;
741 }
742
743 // Wait for an external suspend request to complete (or be cancelled).
744 // Returns true if the thread is externally suspended and false otherwise.
745 //
746 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
747 uint32_t *bits) {
748 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
749 false /* !called_by_wait */, bits);
750
751 // local flag copies to minimize SR_lock hold time
752 bool is_suspended;
753 bool pending;
754 uint32_t reset_bits;
755
756 // set a marker so is_ext_suspend_completed() knows we are the caller
757 *bits |= 0x00010000;
758
759 // We use reset_bits to reinitialize the bits value at the top of
760 // each retry loop. This allows the caller to make use of any
761 // unused bits for their own marking purposes.
762 reset_bits = *bits;
763
764 {
765 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
766 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
767 delay, bits);
768 pending = is_external_suspend();
769 }
770 // must release SR_lock to allow suspension to complete
771
772 if (!pending) {
773 // A cancelled suspend request is the only false return from
774 // is_ext_suspend_completed() that keeps us from entering the
775 // retry loop.
776 *bits |= 0x00020000;
777 return false;
778 }
779
780 if (is_suspended) {
781 *bits |= 0x00040000;
782 return true;
783 }
784
785 for (int i = 1; i <= retries; i++) {
786 *bits = reset_bits; // reinit to only track last retry
787
788 // We used to do an "os::yield_all(i)" call here with the intention
789 // that yielding would increase on each retry. However, the parameter
790 // is ignored on Linux which means the yield didn't scale up. Waiting
791 // on the SR_lock below provides a much more predictable scale up for
792 // the delay. It also provides a simple/direct point to check for any
793 // safepoint requests from the VMThread
794
795 {
796 Thread* t = Thread::current();
797 MonitorLocker ml(SR_lock(),
798 t->is_Java_thread() ? Mutex::_safepoint_check_flag : Mutex::_no_safepoint_check_flag);
799 // wait with safepoint check (if we're a JavaThread - the WatcherThread
800 // can also call this) and increase delay with each retry
801 ml.wait(i * delay);
802
803 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
804 delay, bits);
805
806 // It is possible for the external suspend request to be cancelled
807 // (by a resume) before the actual suspend operation is completed.
808 // Refresh our local copy to see if we still need to wait.
809 pending = is_external_suspend();
810 }
811
812 if (!pending) {
813 // A cancelled suspend request is the only false return from
814 // is_ext_suspend_completed() that keeps us from staying in the
815 // retry loop.
816 *bits |= 0x00080000;
817 return false;
818 }
819
820 if (is_suspended) {
821 *bits |= 0x00100000;
822 return true;
823 }
824 } // end retry loop
825
826 // thread did not suspend after all our retries
827 *bits |= 0x00200000;
828 return false;
829 }
830
831 // Called from API entry points which perform stack walking. If the
832 // associated JavaThread is the current thread, then wait_for_suspend
833 // is not used. Otherwise, it determines if we should wait for the
834 // "other" thread to complete external suspension. (NOTE: in future
835 // releases the suspension mechanism should be reimplemented so this
836 // is not necessary.)
837 //
838 bool
839 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
840 if (this != JavaThread::current()) {
841 // "other" threads require special handling.
842 if (wait_for_suspend) {
843 // We are allowed to wait for the external suspend to complete
844 // so give the other thread a chance to get suspended.
845 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
846 SuspendRetryDelay, bits)) {
847 // Didn't make it so let the caller know.
848 return false;
849 }
850 }
851 // We aren't allowed to wait for the external suspend to complete
852 // so if the other thread isn't externally suspended we need to
853 // let the caller know.
854 else if (!is_ext_suspend_completed_with_lock(bits)) {
855 return false;
856 }
857 }
858
859 return true;
860 }
861
862 #ifndef PRODUCT
863 void JavaThread::record_jump(address target, address instr, const char* file,
864 int line) {
865
866 // This should not need to be atomic as the only way for simultaneous
867 // updates is via interrupts. Even then this should be rare or non-existent
868 // and we don't care that much anyway.
869
870 int index = _jmp_ring_index;
871 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
872 _jmp_ring[index]._target = (intptr_t) target;
873 _jmp_ring[index]._instruction = (intptr_t) instr;
874 _jmp_ring[index]._file = file;
875 _jmp_ring[index]._line = line;
876 }
877 #endif // PRODUCT
878
879 void Thread::interrupt(Thread* thread) {
880 debug_only(check_for_dangling_thread_pointer(thread);)
881 os::interrupt(thread);
882 }
883
884 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
885 debug_only(check_for_dangling_thread_pointer(thread);)
886 // Note: If clear_interrupted==false, this simply fetches and
887 // returns the value of the field osthread()->interrupted().
888 return os::is_interrupted(thread, clear_interrupted);
889 }
890
891
892 // GC Support
893 bool Thread::claim_par_threads_do(uintx claim_token) {
894 uintx token = _threads_do_token;
895 if (token != claim_token) {
896 uintx res = Atomic::cmpxchg(claim_token, &_threads_do_token, token);
897 if (res == token) {
898 return true;
899 }
900 guarantee(res == claim_token, "invariant");
901 }
902 return false;
903 }
904
905 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
906 active_handles()->oops_do(f);
907 // Do oop for ThreadShadow
908 f->do_oop((oop*)&_pending_exception);
909 handle_area()->oops_do(f);
910
911 // We scan thread local monitor lists here, and the remaining global
912 // monitors in ObjectSynchronizer::oops_do().
913 ObjectSynchronizer::thread_local_used_oops_do(this, f);
914 }
915
916 void Thread::metadata_handles_do(void f(Metadata*)) {
917 // Only walk the Handles in Thread.
918 if (metadata_handles() != NULL) {
919 for (int i = 0; i< metadata_handles()->length(); i++) {
920 f(metadata_handles()->at(i));
921 }
922 }
923 }
924
925 void Thread::print_on(outputStream* st, bool print_extended_info) const {
926 // get_priority assumes osthread initialized
927 if (osthread() != NULL) {
928 int os_prio;
929 if (os::get_native_priority(this, &os_prio) == OS_OK) {
930 st->print("os_prio=%d ", os_prio);
931 }
932
933 st->print("cpu=%.2fms ",
934 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
935 );
936 st->print("elapsed=%.2fs ",
937 _statistical_info.getElapsedTime() / 1000.0
938 );
939 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
940 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
941 st->print("allocated=" SIZE_FORMAT "%s ",
942 byte_size_in_proper_unit(allocated_bytes),
943 proper_unit_for_byte_size(allocated_bytes)
944 );
945 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
946 }
947
948 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
949 osthread()->print_on(st);
950 }
951 ThreadsSMRSupport::print_info_on(this, st);
952 st->print(" ");
953 debug_only(if (WizardMode) print_owned_locks_on(st);)
954 }
955
956 void Thread::print() const { print_on(tty); }
957
958 // Thread::print_on_error() is called by fatal error handler. Don't use
959 // any lock or allocate memory.
960 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
961 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
962
963 if (is_VM_thread()) { st->print("VMThread"); }
964 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
965 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
966 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
967 else { st->print("Thread"); }
968
969 if (is_Named_thread()) {
970 st->print(" \"%s\"", name());
971 }
972
973 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
974 p2i(stack_end()), p2i(stack_base()));
975
976 if (osthread()) {
977 st->print(" [id=%d]", osthread()->thread_id());
978 }
979
980 ThreadsSMRSupport::print_info_on(this, st);
981 }
982
983 void Thread::print_value_on(outputStream* st) const {
984 if (is_Named_thread()) {
985 st->print(" \"%s\" ", name());
986 }
987 st->print(INTPTR_FORMAT, p2i(this)); // print address
988 }
989
990 #ifdef ASSERT
991 void Thread::print_owned_locks_on(outputStream* st) const {
992 Monitor *cur = _owned_locks;
993 if (cur == NULL) {
994 st->print(" (no locks) ");
995 } else {
996 st->print_cr(" Locks owned:");
997 while (cur) {
998 cur->print_on(st);
999 cur = cur->next();
1000 }
1001 }
1002 }
1003
1004 static int ref_use_count = 0;
1005
1006 bool Thread::owns_locks_but_compiled_lock() const {
1007 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1008 if (cur != Compile_lock) return true;
1009 }
1010 return false;
1011 }
1012
1013
1014 #endif
1015
1016 #ifndef PRODUCT
1017
1018 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
1019 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
1020 // no locks which allow_vm_block's are held
1021 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
1022 // Check if current thread is allowed to block at a safepoint
1023 if (!(_allow_safepoint_count == 0)) {
1024 fatal("Possible safepoint reached by thread that does not allow it");
1025 }
1026 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
1027 fatal("LEAF method calling lock?");
1028 }
1029
1030 #ifdef ASSERT
1031 if (potential_vm_operation && is_Java_thread()
1032 && !Universe::is_bootstrapping()) {
1033 // Make sure we do not hold any locks that the VM thread also uses.
1034 // This could potentially lead to deadlocks
1035 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1036 // Threads_lock is special, since the safepoint synchronization will not start before this is
1037 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
1038 // since it is used to transfer control between JavaThreads and the VMThread
1039 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
1040 if ((cur->allow_vm_block() &&
1041 cur != Threads_lock &&
1042 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
1043 cur != VMOperationRequest_lock &&
1044 cur != VMOperationQueue_lock) ||
1045 cur->rank() == Mutex::special) {
1046 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
1047 }
1048 }
1049 }
1050
1051 if (GCALotAtAllSafepoints) {
1052 // We could enter a safepoint here and thus have a gc
1053 InterfaceSupport::check_gc_alot();
1054 }
1055 #endif
1056 }
1057 #endif
1058
1059 bool Thread::is_in_stack(address adr) const {
1060 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1061 address end = os::current_stack_pointer();
1062 // Allow non Java threads to call this without stack_base
1063 if (_stack_base == NULL) return true;
1064 if (stack_base() >= adr && adr >= end) return true;
1065
1066 return false;
1067 }
1068
1069 bool Thread::is_in_usable_stack(address adr) const {
1070 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1071 size_t usable_stack_size = _stack_size - stack_guard_size;
1072
1073 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1074 }
1075
1076
1077 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1078 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1079 // used for compilation in the future. If that change is made, the need for these methods
1080 // should be revisited, and they should be removed if possible.
1081
1082 bool Thread::is_lock_owned(address adr) const {
1083 return on_local_stack(adr);
1084 }
1085
1086 bool Thread::set_as_starting_thread() {
1087 assert(_starting_thread == NULL, "already initialized: "
1088 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
1089 // NOTE: this must be called inside the main thread.
1090 DEBUG_ONLY(_starting_thread = this;)
1091 return os::create_main_thread((JavaThread*)this);
1092 }
1093
1094 static void initialize_class(Symbol* class_name, TRAPS) {
1095 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1096 InstanceKlass::cast(klass)->initialize(CHECK);
1097 }
1098
1099
1100 // Creates the initial ThreadGroup
1101 static Handle create_initial_thread_group(TRAPS) {
1102 Handle system_instance = JavaCalls::construct_new_instance(
1103 SystemDictionary::ThreadGroup_klass(),
1104 vmSymbols::void_method_signature(),
1105 CHECK_NH);
1106 Universe::set_system_thread_group(system_instance());
1107
1108 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1109 Handle main_instance = JavaCalls::construct_new_instance(
1110 SystemDictionary::ThreadGroup_klass(),
1111 vmSymbols::threadgroup_string_void_signature(),
1112 system_instance,
1113 string,
1114 CHECK_NH);
1115 return main_instance;
1116 }
1117
1118 // Creates the initial Thread
1119 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1120 TRAPS) {
1121 InstanceKlass* ik = SystemDictionary::Thread_klass();
1122 assert(ik->is_initialized(), "must be");
1123 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1124
1125 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1126 // constructor calls Thread.current(), which must be set here for the
1127 // initial thread.
1128 java_lang_Thread::set_thread(thread_oop(), thread);
1129 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1130 thread->set_threadObj(thread_oop());
1131
1132 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1133
1134 JavaValue result(T_VOID);
1135 JavaCalls::call_special(&result, thread_oop,
1136 ik,
1137 vmSymbols::object_initializer_name(),
1138 vmSymbols::threadgroup_string_void_signature(),
1139 thread_group,
1140 string,
1141 CHECK_NULL);
1142 return thread_oop();
1143 }
1144
1145 char java_runtime_name[128] = "";
1146 char java_runtime_version[128] = "";
1147
1148 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1149 static const char* get_java_runtime_name(TRAPS) {
1150 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1151 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1152 fieldDescriptor fd;
1153 bool found = k != NULL &&
1154 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1155 vmSymbols::string_signature(), &fd);
1156 if (found) {
1157 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1158 if (name_oop == NULL) {
1159 return NULL;
1160 }
1161 const char* name = java_lang_String::as_utf8_string(name_oop,
1162 java_runtime_name,
1163 sizeof(java_runtime_name));
1164 return name;
1165 } else {
1166 return NULL;
1167 }
1168 }
1169
1170 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1171 static const char* get_java_runtime_version(TRAPS) {
1172 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1173 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1174 fieldDescriptor fd;
1175 bool found = k != NULL &&
1176 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1177 vmSymbols::string_signature(), &fd);
1178 if (found) {
1179 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1180 if (name_oop == NULL) {
1181 return NULL;
1182 }
1183 const char* name = java_lang_String::as_utf8_string(name_oop,
1184 java_runtime_version,
1185 sizeof(java_runtime_version));
1186 return name;
1187 } else {
1188 return NULL;
1189 }
1190 }
1191
1192 // General purpose hook into Java code, run once when the VM is initialized.
1193 // The Java library method itself may be changed independently from the VM.
1194 static void call_postVMInitHook(TRAPS) {
1195 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1196 if (klass != NULL) {
1197 JavaValue result(T_VOID);
1198 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1199 vmSymbols::void_method_signature(),
1200 CHECK);
1201 }
1202 }
1203
1204 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1205 bool daemon, TRAPS) {
1206 assert(thread_group.not_null(), "thread group should be specified");
1207 assert(threadObj() == NULL, "should only create Java thread object once");
1208
1209 InstanceKlass* ik = SystemDictionary::Thread_klass();
1210 assert(ik->is_initialized(), "must be");
1211 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1212
1213 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1214 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1215 // constructor calls Thread.current(), which must be set here.
1216 java_lang_Thread::set_thread(thread_oop(), this);
1217 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1218 set_threadObj(thread_oop());
1219
1220 JavaValue result(T_VOID);
1221 if (thread_name != NULL) {
1222 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1223 // Thread gets assigned specified name and null target
1224 JavaCalls::call_special(&result,
1225 thread_oop,
1226 ik,
1227 vmSymbols::object_initializer_name(),
1228 vmSymbols::threadgroup_string_void_signature(),
1229 thread_group,
1230 name,
1231 THREAD);
1232 } else {
1233 // Thread gets assigned name "Thread-nnn" and null target
1234 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1235 JavaCalls::call_special(&result,
1236 thread_oop,
1237 ik,
1238 vmSymbols::object_initializer_name(),
1239 vmSymbols::threadgroup_runnable_void_signature(),
1240 thread_group,
1241 Handle(),
1242 THREAD);
1243 }
1244
1245
1246 if (daemon) {
1247 java_lang_Thread::set_daemon(thread_oop());
1248 }
1249
1250 if (HAS_PENDING_EXCEPTION) {
1251 return;
1252 }
1253
1254 Klass* group = SystemDictionary::ThreadGroup_klass();
1255 Handle threadObj(THREAD, this->threadObj());
1256
1257 JavaCalls::call_special(&result,
1258 thread_group,
1259 group,
1260 vmSymbols::add_method_name(),
1261 vmSymbols::thread_void_signature(),
1262 threadObj, // Arg 1
1263 THREAD);
1264 }
1265
1266 // List of all NonJavaThreads and safe iteration over that list.
1267
1268 class NonJavaThread::List {
1269 public:
1270 NonJavaThread* volatile _head;
1271 SingleWriterSynchronizer _protect;
1272
1273 List() : _head(NULL), _protect() {}
1274 };
1275
1276 NonJavaThread::List NonJavaThread::_the_list;
1277
1278 NonJavaThread::Iterator::Iterator() :
1279 _protect_enter(_the_list._protect.enter()),
1280 _current(OrderAccess::load_acquire(&_the_list._head))
1281 {}
1282
1283 NonJavaThread::Iterator::~Iterator() {
1284 _the_list._protect.exit(_protect_enter);
1285 }
1286
1287 void NonJavaThread::Iterator::step() {
1288 assert(!end(), "precondition");
1289 _current = OrderAccess::load_acquire(&_current->_next);
1290 }
1291
1292 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) {
1293 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!");
1294 }
1295
1296 NonJavaThread::~NonJavaThread() { }
1297
1298 void NonJavaThread::add_to_the_list() {
1299 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1300 // Initialize BarrierSet-related data before adding to list.
1301 BarrierSet::barrier_set()->on_thread_attach(this);
1302 OrderAccess::release_store(&_next, _the_list._head);
1303 OrderAccess::release_store(&_the_list._head, this);
1304 }
1305
1306 void NonJavaThread::remove_from_the_list() {
1307 {
1308 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1309 // Cleanup BarrierSet-related data before removing from list.
1310 BarrierSet::barrier_set()->on_thread_detach(this);
1311 NonJavaThread* volatile* p = &_the_list._head;
1312 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) {
1313 if (t == this) {
1314 *p = _next;
1315 break;
1316 }
1317 }
1318 }
1319 // Wait for any in-progress iterators. Concurrent synchronize is not
1320 // allowed, so do it while holding a dedicated lock. Outside and distinct
1321 // from NJTList_lock in case an iteration attempts to lock it.
1322 MutexLocker ml(NonJavaThreadsListSync_lock, Mutex::_no_safepoint_check_flag);
1323 _the_list._protect.synchronize();
1324 _next = NULL; // Safe to drop the link now.
1325 }
1326
1327 void NonJavaThread::pre_run() {
1328 add_to_the_list();
1329
1330 // This is slightly odd in that NamedThread is a subclass, but
1331 // in fact name() is defined in Thread
1332 assert(this->name() != NULL, "thread name was not set before it was started");
1333 this->set_native_thread_name(this->name());
1334 }
1335
1336 void NonJavaThread::post_run() {
1337 JFR_ONLY(Jfr::on_thread_exit(this);)
1338 remove_from_the_list();
1339 // Ensure thread-local-storage is cleared before termination.
1340 Thread::clear_thread_current();
1341 }
1342
1343 // NamedThread -- non-JavaThread subclasses with multiple
1344 // uniquely named instances should derive from this.
1345 NamedThread::NamedThread() :
1346 NonJavaThread(),
1347 _name(NULL),
1348 _processed_thread(NULL),
1349 _gc_id(GCId::undefined())
1350 {}
1351
1352 NamedThread::~NamedThread() {
1353 if (_name != NULL) {
1354 FREE_C_HEAP_ARRAY(char, _name);
1355 _name = NULL;
1356 }
1357 }
1358
1359 void NamedThread::set_name(const char* format, ...) {
1360 guarantee(_name == NULL, "Only get to set name once.");
1361 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1362 guarantee(_name != NULL, "alloc failure");
1363 va_list ap;
1364 va_start(ap, format);
1365 jio_vsnprintf(_name, max_name_len, format, ap);
1366 va_end(ap);
1367 }
1368
1369 void NamedThread::print_on(outputStream* st) const {
1370 st->print("\"%s\" ", name());
1371 Thread::print_on(st);
1372 st->cr();
1373 }
1374
1375
1376 // ======= WatcherThread ========
1377
1378 // The watcher thread exists to simulate timer interrupts. It should
1379 // be replaced by an abstraction over whatever native support for
1380 // timer interrupts exists on the platform.
1381
1382 WatcherThread* WatcherThread::_watcher_thread = NULL;
1383 bool WatcherThread::_startable = false;
1384 volatile bool WatcherThread::_should_terminate = false;
1385
1386 WatcherThread::WatcherThread() : NonJavaThread() {
1387 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1388 if (os::create_thread(this, os::watcher_thread)) {
1389 _watcher_thread = this;
1390
1391 // Set the watcher thread to the highest OS priority which should not be
1392 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1393 // is created. The only normal thread using this priority is the reference
1394 // handler thread, which runs for very short intervals only.
1395 // If the VMThread's priority is not lower than the WatcherThread profiling
1396 // will be inaccurate.
1397 os::set_priority(this, MaxPriority);
1398 if (!DisableStartThread) {
1399 os::start_thread(this);
1400 }
1401 }
1402 }
1403
1404 int WatcherThread::sleep() const {
1405 // The WatcherThread does not participate in the safepoint protocol
1406 // for the PeriodicTask_lock because it is not a JavaThread.
1407 MonitorLocker ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1408
1409 if (_should_terminate) {
1410 // check for termination before we do any housekeeping or wait
1411 return 0; // we did not sleep.
1412 }
1413
1414 // remaining will be zero if there are no tasks,
1415 // causing the WatcherThread to sleep until a task is
1416 // enrolled
1417 int remaining = PeriodicTask::time_to_wait();
1418 int time_slept = 0;
1419
1420 // we expect this to timeout - we only ever get unparked when
1421 // we should terminate or when a new task has been enrolled
1422 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1423
1424 jlong time_before_loop = os::javaTimeNanos();
1425
1426 while (true) {
1427 bool timedout = ml.wait(remaining);
1428 jlong now = os::javaTimeNanos();
1429
1430 if (remaining == 0) {
1431 // if we didn't have any tasks we could have waited for a long time
1432 // consider the time_slept zero and reset time_before_loop
1433 time_slept = 0;
1434 time_before_loop = now;
1435 } else {
1436 // need to recalculate since we might have new tasks in _tasks
1437 time_slept = (int) ((now - time_before_loop) / 1000000);
1438 }
1439
1440 // Change to task list or spurious wakeup of some kind
1441 if (timedout || _should_terminate) {
1442 break;
1443 }
1444
1445 remaining = PeriodicTask::time_to_wait();
1446 if (remaining == 0) {
1447 // Last task was just disenrolled so loop around and wait until
1448 // another task gets enrolled
1449 continue;
1450 }
1451
1452 remaining -= time_slept;
1453 if (remaining <= 0) {
1454 break;
1455 }
1456 }
1457
1458 return time_slept;
1459 }
1460
1461 void WatcherThread::run() {
1462 assert(this == watcher_thread(), "just checking");
1463
1464 this->set_active_handles(JNIHandleBlock::allocate_block());
1465 while (true) {
1466 assert(watcher_thread() == Thread::current(), "thread consistency check");
1467 assert(watcher_thread() == this, "thread consistency check");
1468
1469 // Calculate how long it'll be until the next PeriodicTask work
1470 // should be done, and sleep that amount of time.
1471 int time_waited = sleep();
1472
1473 if (VMError::is_error_reported()) {
1474 // A fatal error has happened, the error handler(VMError::report_and_die)
1475 // should abort JVM after creating an error log file. However in some
1476 // rare cases, the error handler itself might deadlock. Here periodically
1477 // check for error reporting timeouts, and if it happens, just proceed to
1478 // abort the VM.
1479
1480 // This code is in WatcherThread because WatcherThread wakes up
1481 // periodically so the fatal error handler doesn't need to do anything;
1482 // also because the WatcherThread is less likely to crash than other
1483 // threads.
1484
1485 for (;;) {
1486 // Note: we use naked sleep in this loop because we want to avoid using
1487 // any kind of VM infrastructure which may be broken at this point.
1488 if (VMError::check_timeout()) {
1489 // We hit error reporting timeout. Error reporting was interrupted and
1490 // will be wrapping things up now (closing files etc). Give it some more
1491 // time, then quit the VM.
1492 os::naked_short_sleep(200);
1493 // Print a message to stderr.
1494 fdStream err(defaultStream::output_fd());
1495 err.print_raw_cr("# [ timer expired, abort... ]");
1496 // skip atexit/vm_exit/vm_abort hooks
1497 os::die();
1498 }
1499
1500 // Wait a second, then recheck for timeout.
1501 os::naked_short_sleep(999);
1502 }
1503 }
1504
1505 if (_should_terminate) {
1506 // check for termination before posting the next tick
1507 break;
1508 }
1509
1510 PeriodicTask::real_time_tick(time_waited);
1511 }
1512
1513 // Signal that it is terminated
1514 {
1515 MutexLocker mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1516 _watcher_thread = NULL;
1517 Terminator_lock->notify_all();
1518 }
1519 }
1520
1521 void WatcherThread::start() {
1522 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1523
1524 if (watcher_thread() == NULL && _startable) {
1525 _should_terminate = false;
1526 // Create the single instance of WatcherThread
1527 new WatcherThread();
1528 }
1529 }
1530
1531 void WatcherThread::make_startable() {
1532 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1533 _startable = true;
1534 }
1535
1536 void WatcherThread::stop() {
1537 {
1538 // Follow normal safepoint aware lock enter protocol since the
1539 // WatcherThread is stopped by another JavaThread.
1540 MutexLocker ml(PeriodicTask_lock);
1541 _should_terminate = true;
1542
1543 WatcherThread* watcher = watcher_thread();
1544 if (watcher != NULL) {
1545 // unpark the WatcherThread so it can see that it should terminate
1546 watcher->unpark();
1547 }
1548 }
1549
1550 MonitorLocker mu(Terminator_lock);
1551
1552 while (watcher_thread() != NULL) {
1553 // This wait should make safepoint checks, wait without a timeout,
1554 // and wait as a suspend-equivalent condition.
1555 mu.wait(0, Mutex::_as_suspend_equivalent_flag);
1556 }
1557 }
1558
1559 void WatcherThread::unpark() {
1560 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1561 PeriodicTask_lock->notify();
1562 }
1563
1564 void WatcherThread::print_on(outputStream* st) const {
1565 st->print("\"%s\" ", name());
1566 Thread::print_on(st);
1567 st->cr();
1568 }
1569
1570 // ======= JavaThread ========
1571
1572 #if INCLUDE_JVMCI
1573
1574 jlong* JavaThread::_jvmci_old_thread_counters;
1575
1576 bool jvmci_counters_include(JavaThread* thread) {
1577 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1578 }
1579
1580 void JavaThread::collect_counters(jlong* array, int length) {
1581 assert(length == JVMCICounterSize, "wrong value");
1582 for (int i = 0; i < length; i++) {
1583 array[i] = _jvmci_old_thread_counters[i];
1584 }
1585 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
1586 if (jvmci_counters_include(tp)) {
1587 for (int i = 0; i < length; i++) {
1588 array[i] += tp->_jvmci_counters[i];
1589 }
1590 }
1591 }
1592 }
1593
1594 // Attempt to enlarge the array for per thread counters.
1595 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
1596 jlong* new_counters = NEW_C_HEAP_ARRAY(jlong, new_size, mtJVMCI);
1597 if (new_counters == NULL) {
1598 return NULL;
1599 }
1600 if (old_counters == NULL) {
1601 old_counters = new_counters;
1602 memset(old_counters, 0, sizeof(jlong) * new_size);
1603 } else {
1604 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
1605 new_counters[i] = old_counters[i];
1606 }
1607 if (new_size > current_size) {
1608 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
1609 }
1610 FREE_C_HEAP_ARRAY(jlong, old_counters);
1611 }
1612 return new_counters;
1613 }
1614
1615 // Attempt to enlarge the array for per thread counters.
1616 bool JavaThread::resize_counters(int current_size, int new_size) {
1617 jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
1618 if (new_counters == NULL) {
1619 return false;
1620 } else {
1621 _jvmci_counters = new_counters;
1622 return true;
1623 }
1624 }
1625
1626 class VM_JVMCIResizeCounters : public VM_Operation {
1627 private:
1628 int _new_size;
1629 bool _failed;
1630
1631 public:
1632 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
1633 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
1634 bool allow_nested_vm_operations() const { return true; }
1635 void doit() {
1636 // Resize the old thread counters array
1637 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
1638 if (new_counters == NULL) {
1639 _failed = true;
1640 return;
1641 } else {
1642 JavaThread::_jvmci_old_thread_counters = new_counters;
1643 }
1644
1645 // Now resize each threads array
1646 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
1647 if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
1648 _failed = true;
1649 break;
1650 }
1651 }
1652 if (!_failed) {
1653 JVMCICounterSize = _new_size;
1654 }
1655 }
1656
1657 bool failed() { return _failed; }
1658 };
1659
1660 bool JavaThread::resize_all_jvmci_counters(int new_size) {
1661 VM_JVMCIResizeCounters op(new_size);
1662 VMThread::execute(&op);
1663 return !op.failed();
1664 }
1665
1666 #endif // INCLUDE_JVMCI
1667
1668 // A JavaThread is a normal Java thread
1669
1670 void JavaThread::initialize() {
1671 // Initialize fields
1672
1673 set_saved_exception_pc(NULL);
1674 set_threadObj(NULL);
1675 _anchor.clear();
1676 set_entry_point(NULL);
1677 set_jni_functions(jni_functions());
1678 set_callee_target(NULL);
1679 set_vm_result(NULL);
1680 set_vm_result_2(NULL);
1681 set_vframe_array_head(NULL);
1682 set_vframe_array_last(NULL);
1683 set_deferred_locals(NULL);
1684 set_deopt_mark(NULL);
1685 set_deopt_compiled_method(NULL);
1686 clear_must_deopt_id();
1687 set_monitor_chunks(NULL);
1688 _on_thread_list = false;
1689 set_thread_state(_thread_new);
1690 _terminated = _not_terminated;
1691 _array_for_gc = NULL;
1692 _suspend_equivalent = false;
1693 _in_deopt_handler = 0;
1694 _doing_unsafe_access = false;
1695 _stack_guard_state = stack_guard_unused;
1696 #if INCLUDE_JVMCI
1697 _pending_monitorenter = false;
1698 _pending_deoptimization = -1;
1699 _pending_failed_speculation = 0;
1700 _pending_transfer_to_interpreter = false;
1701 _in_retryable_allocation = false;
1702 _jvmci._alternate_call_target = NULL;
1703 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1704 _jvmci_counters = NULL;
1705 if (JVMCICounterSize > 0) {
1706 resize_counters(0, (int) JVMCICounterSize);
1707 }
1708 #endif // INCLUDE_JVMCI
1709 _reserved_stack_activation = NULL; // stack base not known yet
1710 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1711 _exception_pc = 0;
1712 _exception_handler_pc = 0;
1713 _is_method_handle_return = 0;
1714 _jvmti_thread_state= NULL;
1715 _should_post_on_exceptions_flag = JNI_FALSE;
1716 _interp_only_mode = 0;
1717 _special_runtime_exit_condition = _no_async_condition;
1718 _pending_async_exception = NULL;
1719 _thread_stat = NULL;
1720 _thread_stat = new ThreadStatistics();
1721 _blocked_on_compilation = false;
1722 _jni_active_critical = 0;
1723 _pending_jni_exception_check_fn = NULL;
1724 _do_not_unlock_if_synchronized = false;
1725 _cached_monitor_info = NULL;
1726 _parker = Parker::Allocate(this);
1727
1728 #ifndef PRODUCT
1729 _jmp_ring_index = 0;
1730 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1731 record_jump(NULL, NULL, NULL, 0);
1732 }
1733 #endif // PRODUCT
1734
1735 // Setup safepoint state info for this thread
1736 ThreadSafepointState::create(this);
1737
1738 debug_only(_java_call_counter = 0);
1739
1740 // JVMTI PopFrame support
1741 _popframe_condition = popframe_inactive;
1742 _popframe_preserved_args = NULL;
1743 _popframe_preserved_args_size = 0;
1744 _frames_to_pop_failed_realloc = 0;
1745
1746 if (SafepointMechanism::uses_thread_local_poll()) {
1747 SafepointMechanism::initialize_header(this);
1748 }
1749
1750 _class_to_be_initialized = NULL;
1751
1752 pd_initialize();
1753 }
1754
1755 JavaThread::JavaThread(bool is_attaching_via_jni) :
1756 Thread() {
1757 initialize();
1758 if (is_attaching_via_jni) {
1759 _jni_attach_state = _attaching_via_jni;
1760 } else {
1761 _jni_attach_state = _not_attaching_via_jni;
1762 }
1763 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1764 }
1765
1766 bool JavaThread::reguard_stack(address cur_sp) {
1767 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1768 && _stack_guard_state != stack_guard_reserved_disabled) {
1769 return true; // Stack already guarded or guard pages not needed.
1770 }
1771
1772 if (register_stack_overflow()) {
1773 // For those architectures which have separate register and
1774 // memory stacks, we must check the register stack to see if
1775 // it has overflowed.
1776 return false;
1777 }
1778
1779 // Java code never executes within the yellow zone: the latter is only
1780 // there to provoke an exception during stack banging. If java code
1781 // is executing there, either StackShadowPages should be larger, or
1782 // some exception code in c1, c2 or the interpreter isn't unwinding
1783 // when it should.
1784 guarantee(cur_sp > stack_reserved_zone_base(),
1785 "not enough space to reguard - increase StackShadowPages");
1786 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1787 enable_stack_yellow_reserved_zone();
1788 if (reserved_stack_activation() != stack_base()) {
1789 set_reserved_stack_activation(stack_base());
1790 }
1791 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1792 set_reserved_stack_activation(stack_base());
1793 enable_stack_reserved_zone();
1794 }
1795 return true;
1796 }
1797
1798 bool JavaThread::reguard_stack(void) {
1799 return reguard_stack(os::current_stack_pointer());
1800 }
1801
1802
1803 void JavaThread::block_if_vm_exited() {
1804 if (_terminated == _vm_exited) {
1805 // _vm_exited is set at safepoint, and Threads_lock is never released
1806 // we will block here forever
1807 Threads_lock->lock_without_safepoint_check();
1808 ShouldNotReachHere();
1809 }
1810 }
1811
1812
1813 // Remove this ifdef when C1 is ported to the compiler interface.
1814 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1815 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1816
1817 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1818 Thread() {
1819 initialize();
1820 _jni_attach_state = _not_attaching_via_jni;
1821 set_entry_point(entry_point);
1822 // Create the native thread itself.
1823 // %note runtime_23
1824 os::ThreadType thr_type = os::java_thread;
1825 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1826 os::java_thread;
1827 os::create_thread(this, thr_type, stack_sz);
1828 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1829 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1830 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1831 // the exception consists of creating the exception object & initializing it, initialization
1832 // will leave the VM via a JavaCall and then all locks must be unlocked).
1833 //
1834 // The thread is still suspended when we reach here. Thread must be explicit started
1835 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1836 // by calling Threads:add. The reason why this is not done here, is because the thread
1837 // object must be fully initialized (take a look at JVM_Start)
1838 }
1839
1840 JavaThread::~JavaThread() {
1841
1842 // JSR166 -- return the parker to the free list
1843 Parker::Release(_parker);
1844 _parker = NULL;
1845
1846 // Free any remaining previous UnrollBlock
1847 vframeArray* old_array = vframe_array_last();
1848
1849 if (old_array != NULL) {
1850 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1851 old_array->set_unroll_block(NULL);
1852 delete old_info;
1853 delete old_array;
1854 }
1855
1856 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1857 if (deferred != NULL) {
1858 // This can only happen if thread is destroyed before deoptimization occurs.
1859 assert(deferred->length() != 0, "empty array!");
1860 do {
1861 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1862 deferred->remove_at(0);
1863 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1864 delete dlv;
1865 } while (deferred->length() != 0);
1866 delete deferred;
1867 }
1868
1869 // All Java related clean up happens in exit
1870 ThreadSafepointState::destroy(this);
1871 if (_thread_stat != NULL) delete _thread_stat;
1872
1873 #if INCLUDE_JVMCI
1874 if (JVMCICounterSize > 0) {
1875 if (jvmci_counters_include(this)) {
1876 for (int i = 0; i < JVMCICounterSize; i++) {
1877 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1878 }
1879 }
1880 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1881 }
1882 #endif // INCLUDE_JVMCI
1883 }
1884
1885
1886 // First JavaThread specific code executed by a new Java thread.
1887 void JavaThread::pre_run() {
1888 // empty - see comments in run()
1889 }
1890
1891 // The main routine called by a new Java thread. This isn't overridden
1892 // by subclasses, instead different subclasses define a different "entry_point"
1893 // which defines the actual logic for that kind of thread.
1894 void JavaThread::run() {
1895 // initialize thread-local alloc buffer related fields
1896 this->initialize_tlab();
1897
1898 // Used to test validity of stack trace backs.
1899 // This can't be moved into pre_run() else we invalidate
1900 // the requirement that thread_main_inner is lower on
1901 // the stack. Consequently all the initialization logic
1902 // stays here in run() rather than pre_run().
1903 this->record_base_of_stack_pointer();
1904
1905 this->create_stack_guard_pages();
1906
1907 this->cache_global_variables();
1908
1909 // Thread is now sufficiently initialized to be handled by the safepoint code as being
1910 // in the VM. Change thread state from _thread_new to _thread_in_vm
1911 ThreadStateTransition::transition(this, _thread_new, _thread_in_vm);
1912 // Before a thread is on the threads list it is always safe, so after leaving the
1913 // _thread_new we should emit a instruction barrier. The distance to modified code
1914 // from here is probably far enough, but this is consistent and safe.
1915 OrderAccess::cross_modify_fence();
1916
1917 assert(JavaThread::current() == this, "sanity check");
1918 assert(!Thread::current()->owns_locks(), "sanity check");
1919
1920 DTRACE_THREAD_PROBE(start, this);
1921
1922 // This operation might block. We call that after all safepoint checks for a new thread has
1923 // been completed.
1924 this->set_active_handles(JNIHandleBlock::allocate_block());
1925
1926 if (JvmtiExport::should_post_thread_life()) {
1927 JvmtiExport::post_thread_start(this);
1928
1929 }
1930
1931 // We call another function to do the rest so we are sure that the stack addresses used
1932 // from there will be lower than the stack base just computed.
1933 thread_main_inner();
1934 }
1935
1936 void JavaThread::thread_main_inner() {
1937 assert(JavaThread::current() == this, "sanity check");
1938 assert(this->threadObj() != NULL, "just checking");
1939
1940 // Execute thread entry point unless this thread has a pending exception
1941 // or has been stopped before starting.
1942 // Note: Due to JVM_StopThread we can have pending exceptions already!
1943 if (!this->has_pending_exception() &&
1944 !java_lang_Thread::is_stillborn(this->threadObj())) {
1945 {
1946 ResourceMark rm(this);
1947 this->set_native_thread_name(this->get_thread_name());
1948 }
1949 HandleMark hm(this);
1950 this->entry_point()(this, this);
1951 }
1952
1953 DTRACE_THREAD_PROBE(stop, this);
1954
1955 // Cleanup is handled in post_run()
1956 }
1957
1958 // Shared teardown for all JavaThreads
1959 void JavaThread::post_run() {
1960 this->exit(false);
1961 // Defer deletion to here to ensure 'this' is still referenceable in call_run
1962 // for any shared tear-down.
1963 this->smr_delete();
1964 }
1965
1966 static void ensure_join(JavaThread* thread) {
1967 // We do not need to grab the Threads_lock, since we are operating on ourself.
1968 Handle threadObj(thread, thread->threadObj());
1969 assert(threadObj.not_null(), "java thread object must exist");
1970 ObjectLocker lock(threadObj, thread);
1971 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1972 thread->clear_pending_exception();
1973 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1974 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1975 // Clear the native thread instance - this makes isAlive return false and allows the join()
1976 // to complete once we've done the notify_all below
1977 java_lang_Thread::set_thread(threadObj(), NULL);
1978 lock.notify_all(thread);
1979 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1980 thread->clear_pending_exception();
1981 }
1982
1983 static bool is_daemon(oop threadObj) {
1984 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
1985 }
1986
1987 // For any new cleanup additions, please check to see if they need to be applied to
1988 // cleanup_failed_attach_current_thread as well.
1989 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1990 assert(this == JavaThread::current(), "thread consistency check");
1991
1992 elapsedTimer _timer_exit_phase1;
1993 elapsedTimer _timer_exit_phase2;
1994 elapsedTimer _timer_exit_phase3;
1995 elapsedTimer _timer_exit_phase4;
1996
1997 if (log_is_enabled(Debug, os, thread, timer)) {
1998 _timer_exit_phase1.start();
1999 }
2000
2001 HandleMark hm(this);
2002 Handle uncaught_exception(this, this->pending_exception());
2003 this->clear_pending_exception();
2004 Handle threadObj(this, this->threadObj());
2005 assert(threadObj.not_null(), "Java thread object should be created");
2006
2007 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
2008 {
2009 EXCEPTION_MARK;
2010
2011 CLEAR_PENDING_EXCEPTION;
2012 }
2013 if (!destroy_vm) {
2014 if (uncaught_exception.not_null()) {
2015 EXCEPTION_MARK;
2016 // Call method Thread.dispatchUncaughtException().
2017 Klass* thread_klass = SystemDictionary::Thread_klass();
2018 JavaValue result(T_VOID);
2019 JavaCalls::call_virtual(&result,
2020 threadObj, thread_klass,
2021 vmSymbols::dispatchUncaughtException_name(),
2022 vmSymbols::throwable_void_signature(),
2023 uncaught_exception,
2024 THREAD);
2025 if (HAS_PENDING_EXCEPTION) {
2026 ResourceMark rm(this);
2027 jio_fprintf(defaultStream::error_stream(),
2028 "\nException: %s thrown from the UncaughtExceptionHandler"
2029 " in thread \"%s\"\n",
2030 pending_exception()->klass()->external_name(),
2031 get_thread_name());
2032 CLEAR_PENDING_EXCEPTION;
2033 }
2034 }
2035 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
2036
2037 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
2038 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
2039 // is deprecated anyhow.
2040 if (!is_Compiler_thread()) {
2041 int count = 3;
2042 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
2043 EXCEPTION_MARK;
2044 JavaValue result(T_VOID);
2045 Klass* thread_klass = SystemDictionary::Thread_klass();
2046 JavaCalls::call_virtual(&result,
2047 threadObj, thread_klass,
2048 vmSymbols::exit_method_name(),
2049 vmSymbols::void_method_signature(),
2050 THREAD);
2051 CLEAR_PENDING_EXCEPTION;
2052 }
2053 }
2054 // notify JVMTI
2055 if (JvmtiExport::should_post_thread_life()) {
2056 JvmtiExport::post_thread_end(this);
2057 }
2058
2059 // We have notified the agents that we are exiting, before we go on,
2060 // we must check for a pending external suspend request and honor it
2061 // in order to not surprise the thread that made the suspend request.
2062 while (true) {
2063 {
2064 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2065 if (!is_external_suspend()) {
2066 set_terminated(_thread_exiting);
2067 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
2068 break;
2069 }
2070 // Implied else:
2071 // Things get a little tricky here. We have a pending external
2072 // suspend request, but we are holding the SR_lock so we
2073 // can't just self-suspend. So we temporarily drop the lock
2074 // and then self-suspend.
2075 }
2076
2077 ThreadBlockInVM tbivm(this);
2078 java_suspend_self();
2079
2080 // We're done with this suspend request, but we have to loop around
2081 // and check again. Eventually we will get SR_lock without a pending
2082 // external suspend request and will be able to mark ourselves as
2083 // exiting.
2084 }
2085 // no more external suspends are allowed at this point
2086 } else {
2087 assert(!is_terminated() && !is_exiting(), "must not be exiting");
2088 // before_exit() has already posted JVMTI THREAD_END events
2089 }
2090
2091 if (log_is_enabled(Debug, os, thread, timer)) {
2092 _timer_exit_phase1.stop();
2093 _timer_exit_phase2.start();
2094 }
2095
2096 // Capture daemon status before the thread is marked as terminated.
2097 bool daemon = is_daemon(threadObj());
2098
2099 // Notify waiters on thread object. This has to be done after exit() is called
2100 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
2101 // group should have the destroyed bit set before waiters are notified).
2102 ensure_join(this);
2103 assert(!this->has_pending_exception(), "ensure_join should have cleared");
2104
2105 if (log_is_enabled(Debug, os, thread, timer)) {
2106 _timer_exit_phase2.stop();
2107 _timer_exit_phase3.start();
2108 }
2109 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
2110 // held by this thread must be released. The spec does not distinguish
2111 // between JNI-acquired and regular Java monitors. We can only see
2112 // regular Java monitors here if monitor enter-exit matching is broken.
2113 //
2114 // ensure_join() ignores IllegalThreadStateExceptions, and so does
2115 // ObjectSynchronizer::release_monitors_owned_by_thread().
2116 if (exit_type == jni_detach) {
2117 // Sanity check even though JNI DetachCurrentThread() would have
2118 // returned JNI_ERR if there was a Java frame. JavaThread exit
2119 // should be done executing Java code by the time we get here.
2120 assert(!this->has_last_Java_frame(),
2121 "should not have a Java frame when detaching or exiting");
2122 ObjectSynchronizer::release_monitors_owned_by_thread(this);
2123 assert(!this->has_pending_exception(), "release_monitors should have cleared");
2124 }
2125
2126 // These things needs to be done while we are still a Java Thread. Make sure that thread
2127 // is in a consistent state, in case GC happens
2128 JFR_ONLY(Jfr::on_thread_exit(this);)
2129
2130 if (active_handles() != NULL) {
2131 JNIHandleBlock* block = active_handles();
2132 set_active_handles(NULL);
2133 JNIHandleBlock::release_block(block);
2134 }
2135
2136 if (free_handle_block() != NULL) {
2137 JNIHandleBlock* block = free_handle_block();
2138 set_free_handle_block(NULL);
2139 JNIHandleBlock::release_block(block);
2140 }
2141
2142 // These have to be removed while this is still a valid thread.
2143 remove_stack_guard_pages();
2144
2145 if (UseTLAB) {
2146 tlab().retire();
2147 }
2148
2149 if (JvmtiEnv::environments_might_exist()) {
2150 JvmtiExport::cleanup_thread(this);
2151 }
2152
2153 // We must flush any deferred card marks and other various GC barrier
2154 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2155 // before removing a thread from the list of active threads.
2156 BarrierSet::barrier_set()->on_thread_detach(this);
2157
2158 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2159 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2160 os::current_thread_id());
2161
2162 if (log_is_enabled(Debug, os, thread, timer)) {
2163 _timer_exit_phase3.stop();
2164 _timer_exit_phase4.start();
2165 }
2166 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2167 Threads::remove(this, daemon);
2168
2169 if (log_is_enabled(Debug, os, thread, timer)) {
2170 _timer_exit_phase4.stop();
2171 ResourceMark rm(this);
2172 log_debug(os, thread, timer)("name='%s'"
2173 ", exit-phase1=" JLONG_FORMAT
2174 ", exit-phase2=" JLONG_FORMAT
2175 ", exit-phase3=" JLONG_FORMAT
2176 ", exit-phase4=" JLONG_FORMAT,
2177 get_thread_name(),
2178 _timer_exit_phase1.milliseconds(),
2179 _timer_exit_phase2.milliseconds(),
2180 _timer_exit_phase3.milliseconds(),
2181 _timer_exit_phase4.milliseconds());
2182 }
2183 }
2184
2185 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
2186 if (active_handles() != NULL) {
2187 JNIHandleBlock* block = active_handles();
2188 set_active_handles(NULL);
2189 JNIHandleBlock::release_block(block);
2190 }
2191
2192 if (free_handle_block() != NULL) {
2193 JNIHandleBlock* block = free_handle_block();
2194 set_free_handle_block(NULL);
2195 JNIHandleBlock::release_block(block);
2196 }
2197
2198 // These have to be removed while this is still a valid thread.
2199 remove_stack_guard_pages();
2200
2201 if (UseTLAB) {
2202 tlab().retire();
2203 }
2204
2205 BarrierSet::barrier_set()->on_thread_detach(this);
2206
2207 Threads::remove(this, is_daemon);
2208 this->smr_delete();
2209 }
2210
2211 JavaThread* JavaThread::active() {
2212 Thread* thread = Thread::current();
2213 if (thread->is_Java_thread()) {
2214 return (JavaThread*) thread;
2215 } else {
2216 assert(thread->is_VM_thread(), "this must be a vm thread");
2217 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2218 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2219 assert(ret->is_Java_thread(), "must be a Java thread");
2220 return ret;
2221 }
2222 }
2223
2224 bool JavaThread::is_lock_owned(address adr) const {
2225 if (Thread::is_lock_owned(adr)) return true;
2226
2227 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2228 if (chunk->contains(adr)) return true;
2229 }
2230
2231 return false;
2232 }
2233
2234
2235 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2236 chunk->set_next(monitor_chunks());
2237 set_monitor_chunks(chunk);
2238 }
2239
2240 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2241 guarantee(monitor_chunks() != NULL, "must be non empty");
2242 if (monitor_chunks() == chunk) {
2243 set_monitor_chunks(chunk->next());
2244 } else {
2245 MonitorChunk* prev = monitor_chunks();
2246 while (prev->next() != chunk) prev = prev->next();
2247 prev->set_next(chunk->next());
2248 }
2249 }
2250
2251 // JVM support.
2252
2253 // Note: this function shouldn't block if it's called in
2254 // _thread_in_native_trans state (such as from
2255 // check_special_condition_for_native_trans()).
2256 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2257
2258 if (has_last_Java_frame() && has_async_condition()) {
2259 // If we are at a polling page safepoint (not a poll return)
2260 // then we must defer async exception because live registers
2261 // will be clobbered by the exception path. Poll return is
2262 // ok because the call we a returning from already collides
2263 // with exception handling registers and so there is no issue.
2264 // (The exception handling path kills call result registers but
2265 // this is ok since the exception kills the result anyway).
2266
2267 if (is_at_poll_safepoint()) {
2268 // if the code we are returning to has deoptimized we must defer
2269 // the exception otherwise live registers get clobbered on the
2270 // exception path before deoptimization is able to retrieve them.
2271 //
2272 RegisterMap map(this, false);
2273 frame caller_fr = last_frame().sender(&map);
2274 assert(caller_fr.is_compiled_frame(), "what?");
2275 if (caller_fr.is_deoptimized_frame()) {
2276 log_info(exceptions)("deferred async exception at compiled safepoint");
2277 return;
2278 }
2279 }
2280 }
2281
2282 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2283 if (condition == _no_async_condition) {
2284 // Conditions have changed since has_special_runtime_exit_condition()
2285 // was called:
2286 // - if we were here only because of an external suspend request,
2287 // then that was taken care of above (or cancelled) so we are done
2288 // - if we were here because of another async request, then it has
2289 // been cleared between the has_special_runtime_exit_condition()
2290 // and now so again we are done
2291 return;
2292 }
2293
2294 // Check for pending async. exception
2295 if (_pending_async_exception != NULL) {
2296 // Only overwrite an already pending exception, if it is not a threadDeath.
2297 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2298
2299 // We cannot call Exceptions::_throw(...) here because we cannot block
2300 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2301
2302 LogTarget(Info, exceptions) lt;
2303 if (lt.is_enabled()) {
2304 ResourceMark rm;
2305 LogStream ls(lt);
2306 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2307 if (has_last_Java_frame()) {
2308 frame f = last_frame();
2309 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2310 }
2311 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2312 }
2313 _pending_async_exception = NULL;
2314 clear_has_async_exception();
2315 }
2316 }
2317
2318 if (check_unsafe_error &&
2319 condition == _async_unsafe_access_error && !has_pending_exception()) {
2320 condition = _no_async_condition; // done
2321 switch (thread_state()) {
2322 case _thread_in_vm: {
2323 JavaThread* THREAD = this;
2324 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2325 }
2326 case _thread_in_native: {
2327 ThreadInVMfromNative tiv(this);
2328 JavaThread* THREAD = this;
2329 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2330 }
2331 case _thread_in_Java: {
2332 ThreadInVMfromJava tiv(this);
2333 JavaThread* THREAD = this;
2334 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2335 }
2336 default:
2337 ShouldNotReachHere();
2338 }
2339 }
2340
2341 assert(condition == _no_async_condition || has_pending_exception() ||
2342 (!check_unsafe_error && condition == _async_unsafe_access_error),
2343 "must have handled the async condition, if no exception");
2344 }
2345
2346 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2347 //
2348 // Check for pending external suspend.
2349 // If JNIEnv proxies are allowed, don't self-suspend if the target
2350 // thread is not the current thread. In older versions of jdbx, jdbx
2351 // threads could call into the VM with another thread's JNIEnv so we
2352 // can be here operating on behalf of a suspended thread (4432884).
2353 bool do_self_suspend = is_external_suspend_with_lock();
2354 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2355 frame_anchor()->make_walkable(this);
2356 java_suspend_self_with_safepoint_check();
2357 }
2358
2359 // We might be here for reasons in addition to the self-suspend request
2360 // so check for other async requests.
2361 if (check_asyncs) {
2362 check_and_handle_async_exceptions();
2363 }
2364
2365 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2366 }
2367
2368 void JavaThread::send_thread_stop(oop java_throwable) {
2369 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2370 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2371 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2372
2373 // Do not throw asynchronous exceptions against the compiler thread
2374 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2375 if (!can_call_java()) return;
2376
2377 {
2378 // Actually throw the Throwable against the target Thread - however
2379 // only if there is no thread death exception installed already.
2380 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2381 // If the topmost frame is a runtime stub, then we are calling into
2382 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2383 // must deoptimize the caller before continuing, as the compiled exception handler table
2384 // may not be valid
2385 if (has_last_Java_frame()) {
2386 frame f = last_frame();
2387 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2388 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2389 RegisterMap reg_map(this, UseBiasedLocking);
2390 frame compiled_frame = f.sender(®_map);
2391 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2392 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2393 }
2394 }
2395 }
2396
2397 // Set async. pending exception in thread.
2398 set_pending_async_exception(java_throwable);
2399
2400 if (log_is_enabled(Info, exceptions)) {
2401 ResourceMark rm;
2402 log_info(exceptions)("Pending Async. exception installed of type: %s",
2403 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2404 }
2405 // for AbortVMOnException flag
2406 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2407 }
2408 }
2409
2410
2411 // Interrupt thread so it will wake up from a potential wait()
2412 Thread::interrupt(this);
2413 }
2414
2415 // External suspension mechanism.
2416 //
2417 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2418 // to any VM_locks and it is at a transition
2419 // Self-suspension will happen on the transition out of the vm.
2420 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2421 //
2422 // Guarantees on return:
2423 // + Target thread will not execute any new bytecode (that's why we need to
2424 // force a safepoint)
2425 // + Target thread will not enter any new monitors
2426 //
2427 void JavaThread::java_suspend() {
2428 ThreadsListHandle tlh;
2429 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2430 return;
2431 }
2432
2433 { MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2434 if (!is_external_suspend()) {
2435 // a racing resume has cancelled us; bail out now
2436 return;
2437 }
2438
2439 // suspend is done
2440 uint32_t debug_bits = 0;
2441 // Warning: is_ext_suspend_completed() may temporarily drop the
2442 // SR_lock to allow the thread to reach a stable thread state if
2443 // it is currently in a transient thread state.
2444 if (is_ext_suspend_completed(false /* !called_by_wait */,
2445 SuspendRetryDelay, &debug_bits)) {
2446 return;
2447 }
2448 }
2449
2450 if (Thread::current() == this) {
2451 // Safely self-suspend.
2452 // If we don't do this explicitly it will implicitly happen
2453 // before we transition back to Java, and on some other thread-state
2454 // transition paths, but not as we exit a JVM TI SuspendThread call.
2455 // As SuspendThread(current) must not return (until resumed) we must
2456 // self-suspend here.
2457 ThreadBlockInVM tbivm(this);
2458 java_suspend_self();
2459 } else {
2460 VM_ThreadSuspend vm_suspend;
2461 VMThread::execute(&vm_suspend);
2462 }
2463 }
2464
2465 // Part II of external suspension.
2466 // A JavaThread self suspends when it detects a pending external suspend
2467 // request. This is usually on transitions. It is also done in places
2468 // where continuing to the next transition would surprise the caller,
2469 // e.g., monitor entry.
2470 //
2471 // Returns the number of times that the thread self-suspended.
2472 //
2473 // Note: DO NOT call java_suspend_self() when you just want to block current
2474 // thread. java_suspend_self() is the second stage of cooperative
2475 // suspension for external suspend requests and should only be used
2476 // to complete an external suspend request.
2477 //
2478 int JavaThread::java_suspend_self() {
2479 assert(thread_state() == _thread_blocked, "wrong state for java_suspend_self()");
2480 int ret = 0;
2481
2482 // we are in the process of exiting so don't suspend
2483 if (is_exiting()) {
2484 clear_external_suspend();
2485 return ret;
2486 }
2487
2488 assert(_anchor.walkable() ||
2489 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2490 "must have walkable stack");
2491
2492 MonitorLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2493
2494 assert(!this->is_ext_suspended(),
2495 "a thread trying to self-suspend should not already be suspended");
2496
2497 if (this->is_suspend_equivalent()) {
2498 // If we are self-suspending as a result of the lifting of a
2499 // suspend equivalent condition, then the suspend_equivalent
2500 // flag is not cleared until we set the ext_suspended flag so
2501 // that wait_for_ext_suspend_completion() returns consistent
2502 // results.
2503 this->clear_suspend_equivalent();
2504 }
2505
2506 // A racing resume may have cancelled us before we grabbed SR_lock
2507 // above. Or another external suspend request could be waiting for us
2508 // by the time we return from SR_lock()->wait(). The thread
2509 // that requested the suspension may already be trying to walk our
2510 // stack and if we return now, we can change the stack out from under
2511 // it. This would be a "bad thing (TM)" and cause the stack walker
2512 // to crash. We stay self-suspended until there are no more pending
2513 // external suspend requests.
2514 while (is_external_suspend()) {
2515 ret++;
2516 this->set_ext_suspended();
2517
2518 // _ext_suspended flag is cleared by java_resume()
2519 while (is_ext_suspended()) {
2520 ml.wait();
2521 }
2522 }
2523 return ret;
2524 }
2525
2526 // Helper routine to set up the correct thread state before calling java_suspend_self.
2527 // This is called when regular thread-state transition helpers can't be used because
2528 // we can be in various states, in particular _thread_in_native_trans.
2529 // Because this thread is external suspended the safepoint code will count it as at
2530 // a safepoint, regardless of what its actual current thread-state is. But
2531 // is_ext_suspend_completed() may be waiting to see a thread transition from
2532 // _thread_in_native_trans to _thread_blocked. So we set the thread state directly
2533 // to _thread_blocked. The problem with setting thread state directly is that a
2534 // safepoint could happen just after java_suspend_self() returns after being resumed,
2535 // and the VM thread will see the _thread_blocked state. So we must check for a safepoint
2536 // after restoring the state to make sure we won't leave while a safepoint is in progress.
2537 // However, not all initial-states are allowed when performing a safepoint check, as we
2538 // should never be blocking at a safepoint whilst in those states. Of these 'bad' states
2539 // only _thread_in_native is possible when executing this code (based on our two callers).
2540 // A thread that is _thread_in_native is already safepoint-safe and so it doesn't matter
2541 // whether the VMThread sees the _thread_blocked state, or the _thread_in_native state,
2542 // and so we don't need the explicit safepoint check.
2543
2544 void JavaThread::java_suspend_self_with_safepoint_check() {
2545 assert(this == Thread::current(), "invariant");
2546 JavaThreadState state = thread_state();
2547 set_thread_state(_thread_blocked);
2548 java_suspend_self();
2549 set_thread_state_fence(state);
2550 // Since we are not using a regular thread-state transition helper here,
2551 // we must manually emit the instruction barrier after leaving a safe state.
2552 OrderAccess::cross_modify_fence();
2553 if (state != _thread_in_native) {
2554 SafepointMechanism::block_if_requested(this);
2555 }
2556 }
2557
2558 #ifdef ASSERT
2559 // Verify the JavaThread has not yet been published in the Threads::list, and
2560 // hence doesn't need protection from concurrent access at this stage.
2561 void JavaThread::verify_not_published() {
2562 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2563 // since an unpublished JavaThread doesn't participate in the
2564 // Thread-SMR protocol for keeping a ThreadsList alive.
2565 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2566 }
2567 #endif
2568
2569 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2570 // progress or when _suspend_flags is non-zero.
2571 // Current thread needs to self-suspend if there is a suspend request and/or
2572 // block if a safepoint is in progress.
2573 // Async exception ISN'T checked.
2574 // Note only the ThreadInVMfromNative transition can call this function
2575 // directly and when thread state is _thread_in_native_trans
2576 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2577 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2578
2579 JavaThread *curJT = JavaThread::current();
2580 bool do_self_suspend = thread->is_external_suspend();
2581
2582 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2583
2584 // If JNIEnv proxies are allowed, don't self-suspend if the target
2585 // thread is not the current thread. In older versions of jdbx, jdbx
2586 // threads could call into the VM with another thread's JNIEnv so we
2587 // can be here operating on behalf of a suspended thread (4432884).
2588 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2589 thread->java_suspend_self_with_safepoint_check();
2590 } else {
2591 SafepointMechanism::block_if_requested(curJT);
2592 }
2593
2594 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2595 }
2596
2597 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2598 // progress or when _suspend_flags is non-zero.
2599 // Current thread needs to self-suspend if there is a suspend request and/or
2600 // block if a safepoint is in progress.
2601 // Also check for pending async exception (not including unsafe access error).
2602 // Note only the native==>VM/Java barriers can call this function and when
2603 // thread state is _thread_in_native_trans.
2604 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2605 check_safepoint_and_suspend_for_native_trans(thread);
2606
2607 if (thread->has_async_exception()) {
2608 // We are in _thread_in_native_trans state, don't handle unsafe
2609 // access error since that may block.
2610 thread->check_and_handle_async_exceptions(false);
2611 }
2612 }
2613
2614 // This is a variant of the normal
2615 // check_special_condition_for_native_trans with slightly different
2616 // semantics for use by critical native wrappers. It does all the
2617 // normal checks but also performs the transition back into
2618 // thread_in_Java state. This is required so that critical natives
2619 // can potentially block and perform a GC if they are the last thread
2620 // exiting the GCLocker.
2621 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2622 check_special_condition_for_native_trans(thread);
2623
2624 // Finish the transition
2625 thread->set_thread_state(_thread_in_Java);
2626
2627 if (thread->do_critical_native_unlock()) {
2628 ThreadInVMfromJavaNoAsyncException tiv(thread);
2629 GCLocker::unlock_critical(thread);
2630 thread->clear_critical_native_unlock();
2631 }
2632 }
2633
2634 // We need to guarantee the Threads_lock here, since resumes are not
2635 // allowed during safepoint synchronization
2636 // Can only resume from an external suspension
2637 void JavaThread::java_resume() {
2638 assert_locked_or_safepoint(Threads_lock);
2639
2640 // Sanity check: thread is gone, has started exiting or the thread
2641 // was not externally suspended.
2642 ThreadsListHandle tlh;
2643 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2644 return;
2645 }
2646
2647 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2648
2649 clear_external_suspend();
2650
2651 if (is_ext_suspended()) {
2652 clear_ext_suspended();
2653 SR_lock()->notify_all();
2654 }
2655 }
2656
2657 size_t JavaThread::_stack_red_zone_size = 0;
2658 size_t JavaThread::_stack_yellow_zone_size = 0;
2659 size_t JavaThread::_stack_reserved_zone_size = 0;
2660 size_t JavaThread::_stack_shadow_zone_size = 0;
2661
2662 void JavaThread::create_stack_guard_pages() {
2663 if (!os::uses_stack_guard_pages() ||
2664 _stack_guard_state != stack_guard_unused ||
2665 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2666 log_info(os, thread)("Stack guard page creation for thread "
2667 UINTX_FORMAT " disabled", os::current_thread_id());
2668 return;
2669 }
2670 address low_addr = stack_end();
2671 size_t len = stack_guard_zone_size();
2672
2673 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2674 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2675
2676 int must_commit = os::must_commit_stack_guard_pages();
2677 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2678
2679 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2680 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2681 return;
2682 }
2683
2684 if (os::guard_memory((char *) low_addr, len)) {
2685 _stack_guard_state = stack_guard_enabled;
2686 } else {
2687 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2688 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2689 if (os::uncommit_memory((char *) low_addr, len)) {
2690 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2691 }
2692 return;
2693 }
2694
2695 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2696 PTR_FORMAT "-" PTR_FORMAT ".",
2697 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2698 }
2699
2700 void JavaThread::remove_stack_guard_pages() {
2701 assert(Thread::current() == this, "from different thread");
2702 if (_stack_guard_state == stack_guard_unused) return;
2703 address low_addr = stack_end();
2704 size_t len = stack_guard_zone_size();
2705
2706 if (os::must_commit_stack_guard_pages()) {
2707 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2708 _stack_guard_state = stack_guard_unused;
2709 } else {
2710 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2711 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2712 return;
2713 }
2714 } else {
2715 if (_stack_guard_state == stack_guard_unused) return;
2716 if (os::unguard_memory((char *) low_addr, len)) {
2717 _stack_guard_state = stack_guard_unused;
2718 } else {
2719 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2720 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2721 return;
2722 }
2723 }
2724
2725 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2726 PTR_FORMAT "-" PTR_FORMAT ".",
2727 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2728 }
2729
2730 void JavaThread::enable_stack_reserved_zone() {
2731 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state");
2732
2733 // The base notation is from the stack's point of view, growing downward.
2734 // We need to adjust it to work correctly with guard_memory()
2735 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2736
2737 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2738 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2739
2740 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2741 _stack_guard_state = stack_guard_enabled;
2742 } else {
2743 warning("Attempt to guard stack reserved zone failed.");
2744 }
2745 enable_register_stack_guard();
2746 }
2747
2748 void JavaThread::disable_stack_reserved_zone() {
2749 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state");
2750
2751 // Simply return if called for a thread that does not use guard pages.
2752 if (_stack_guard_state != stack_guard_enabled) return;
2753
2754 // The base notation is from the stack's point of view, growing downward.
2755 // We need to adjust it to work correctly with guard_memory()
2756 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2757
2758 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2759 _stack_guard_state = stack_guard_reserved_disabled;
2760 } else {
2761 warning("Attempt to unguard stack reserved zone failed.");
2762 }
2763 disable_register_stack_guard();
2764 }
2765
2766 void JavaThread::enable_stack_yellow_reserved_zone() {
2767 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2768 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2769
2770 // The base notation is from the stacks point of view, growing downward.
2771 // We need to adjust it to work correctly with guard_memory()
2772 address base = stack_red_zone_base();
2773
2774 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2775 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2776
2777 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2778 _stack_guard_state = stack_guard_enabled;
2779 } else {
2780 warning("Attempt to guard stack yellow zone failed.");
2781 }
2782 enable_register_stack_guard();
2783 }
2784
2785 void JavaThread::disable_stack_yellow_reserved_zone() {
2786 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2787 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2788
2789 // Simply return if called for a thread that does not use guard pages.
2790 if (_stack_guard_state == stack_guard_unused) return;
2791
2792 // The base notation is from the stacks point of view, growing downward.
2793 // We need to adjust it to work correctly with guard_memory()
2794 address base = stack_red_zone_base();
2795
2796 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2797 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2798 } else {
2799 warning("Attempt to unguard stack yellow zone failed.");
2800 }
2801 disable_register_stack_guard();
2802 }
2803
2804 void JavaThread::enable_stack_red_zone() {
2805 // The base notation is from the stacks point of view, growing downward.
2806 // We need to adjust it to work correctly with guard_memory()
2807 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2808 address base = stack_red_zone_base() - stack_red_zone_size();
2809
2810 guarantee(base < stack_base(), "Error calculating stack red zone");
2811 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2812
2813 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2814 warning("Attempt to guard stack red zone failed.");
2815 }
2816 }
2817
2818 void JavaThread::disable_stack_red_zone() {
2819 // The base notation is from the stacks point of view, growing downward.
2820 // We need to adjust it to work correctly with guard_memory()
2821 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2822 address base = stack_red_zone_base() - stack_red_zone_size();
2823 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2824 warning("Attempt to unguard stack red zone failed.");
2825 }
2826 }
2827
2828 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2829 // ignore is there is no stack
2830 if (!has_last_Java_frame()) return;
2831 // traverse the stack frames. Starts from top frame.
2832 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2833 frame* fr = fst.current();
2834 f(fr, fst.register_map());
2835 }
2836 }
2837
2838
2839 #ifndef PRODUCT
2840 // Deoptimization
2841 // Function for testing deoptimization
2842 void JavaThread::deoptimize() {
2843 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2844 StackFrameStream fst(this, UseBiasedLocking);
2845 bool deopt = false; // Dump stack only if a deopt actually happens.
2846 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2847 // Iterate over all frames in the thread and deoptimize
2848 for (; !fst.is_done(); fst.next()) {
2849 if (fst.current()->can_be_deoptimized()) {
2850
2851 if (only_at) {
2852 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2853 // consists of comma or carriage return separated numbers so
2854 // search for the current bci in that string.
2855 address pc = fst.current()->pc();
2856 nmethod* nm = (nmethod*) fst.current()->cb();
2857 ScopeDesc* sd = nm->scope_desc_at(pc);
2858 char buffer[8];
2859 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2860 size_t len = strlen(buffer);
2861 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2862 while (found != NULL) {
2863 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2864 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2865 // Check that the bci found is bracketed by terminators.
2866 break;
2867 }
2868 found = strstr(found + 1, buffer);
2869 }
2870 if (!found) {
2871 continue;
2872 }
2873 }
2874
2875 if (DebugDeoptimization && !deopt) {
2876 deopt = true; // One-time only print before deopt
2877 tty->print_cr("[BEFORE Deoptimization]");
2878 trace_frames();
2879 trace_stack();
2880 }
2881 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2882 }
2883 }
2884
2885 if (DebugDeoptimization && deopt) {
2886 tty->print_cr("[AFTER Deoptimization]");
2887 trace_frames();
2888 }
2889 }
2890
2891
2892 // Make zombies
2893 void JavaThread::make_zombies() {
2894 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2895 if (fst.current()->can_be_deoptimized()) {
2896 // it is a Java nmethod
2897 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2898 nm->make_not_entrant();
2899 }
2900 }
2901 }
2902 #endif // PRODUCT
2903
2904
2905 void JavaThread::deoptimize_marked_methods(bool in_handshake) {
2906 if (!has_last_Java_frame()) return;
2907 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2908 StackFrameStream fst(this, UseBiasedLocking);
2909 for (; !fst.is_done(); fst.next()) {
2910 if (fst.current()->should_be_deoptimized()) {
2911 Deoptimization::deoptimize(this, *fst.current(), fst.register_map(), in_handshake);
2912 }
2913 }
2914 }
2915
2916 // If the caller is a NamedThread, then remember, in the current scope,
2917 // the given JavaThread in its _processed_thread field.
2918 class RememberProcessedThread: public StackObj {
2919 NamedThread* _cur_thr;
2920 public:
2921 RememberProcessedThread(JavaThread* jthr) {
2922 Thread* thread = Thread::current();
2923 if (thread->is_Named_thread()) {
2924 _cur_thr = (NamedThread *)thread;
2925 _cur_thr->set_processed_thread(jthr);
2926 } else {
2927 _cur_thr = NULL;
2928 }
2929 }
2930
2931 ~RememberProcessedThread() {
2932 if (_cur_thr) {
2933 _cur_thr->set_processed_thread(NULL);
2934 }
2935 }
2936 };
2937
2938 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2939 // Verify that the deferred card marks have been flushed.
2940 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2941
2942 // Traverse the GCHandles
2943 Thread::oops_do(f, cf);
2944
2945 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2946 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2947
2948 if (has_last_Java_frame()) {
2949 // Record JavaThread to GC thread
2950 RememberProcessedThread rpt(this);
2951
2952 // traverse the registered growable array
2953 if (_array_for_gc != NULL) {
2954 for (int index = 0; index < _array_for_gc->length(); index++) {
2955 f->do_oop(_array_for_gc->adr_at(index));
2956 }
2957 }
2958
2959 // Traverse the monitor chunks
2960 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2961 chunk->oops_do(f);
2962 }
2963
2964 // Traverse the execution stack
2965 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2966 fst.current()->oops_do(f, cf, fst.register_map());
2967 }
2968 }
2969
2970 // callee_target is never live across a gc point so NULL it here should
2971 // it still contain a methdOop.
2972
2973 set_callee_target(NULL);
2974
2975 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2976 // If we have deferred set_locals there might be oops waiting to be
2977 // written
2978 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2979 if (list != NULL) {
2980 for (int i = 0; i < list->length(); i++) {
2981 list->at(i)->oops_do(f);
2982 }
2983 }
2984
2985 // Traverse instance variables at the end since the GC may be moving things
2986 // around using this function
2987 f->do_oop((oop*) &_threadObj);
2988 f->do_oop((oop*) &_vm_result);
2989 f->do_oop((oop*) &_exception_oop);
2990 f->do_oop((oop*) &_pending_async_exception);
2991
2992 if (jvmti_thread_state() != NULL) {
2993 jvmti_thread_state()->oops_do(f);
2994 }
2995 }
2996
2997 #ifdef ASSERT
2998 void JavaThread::verify_states_for_handshake() {
2999 // This checks that the thread has a correct frame state during a handshake.
3000 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
3001 (has_last_Java_frame() && java_call_counter() > 0),
3002 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
3003 has_last_Java_frame(), java_call_counter());
3004 }
3005 #endif
3006
3007 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
3008 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
3009 (has_last_Java_frame() && java_call_counter() > 0),
3010 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
3011 has_last_Java_frame(), java_call_counter());
3012
3013 if (has_last_Java_frame()) {
3014 // Traverse the execution stack
3015 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3016 fst.current()->nmethods_do(cf);
3017 }
3018 }
3019 }
3020
3021 void JavaThread::metadata_do(MetadataClosure* f) {
3022 if (has_last_Java_frame()) {
3023 // Traverse the execution stack to call f() on the methods in the stack
3024 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3025 fst.current()->metadata_do(f);
3026 }
3027 } else if (is_Compiler_thread()) {
3028 // need to walk ciMetadata in current compile tasks to keep alive.
3029 CompilerThread* ct = (CompilerThread*)this;
3030 if (ct->env() != NULL) {
3031 ct->env()->metadata_do(f);
3032 }
3033 CompileTask* task = ct->task();
3034 if (task != NULL) {
3035 task->metadata_do(f);
3036 }
3037 }
3038 }
3039
3040 // Printing
3041 const char* _get_thread_state_name(JavaThreadState _thread_state) {
3042 switch (_thread_state) {
3043 case _thread_uninitialized: return "_thread_uninitialized";
3044 case _thread_new: return "_thread_new";
3045 case _thread_new_trans: return "_thread_new_trans";
3046 case _thread_in_native: return "_thread_in_native";
3047 case _thread_in_native_trans: return "_thread_in_native_trans";
3048 case _thread_in_vm: return "_thread_in_vm";
3049 case _thread_in_vm_trans: return "_thread_in_vm_trans";
3050 case _thread_in_Java: return "_thread_in_Java";
3051 case _thread_in_Java_trans: return "_thread_in_Java_trans";
3052 case _thread_blocked: return "_thread_blocked";
3053 case _thread_blocked_trans: return "_thread_blocked_trans";
3054 default: return "unknown thread state";
3055 }
3056 }
3057
3058 #ifndef PRODUCT
3059 void JavaThread::print_thread_state_on(outputStream *st) const {
3060 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
3061 };
3062 void JavaThread::print_thread_state() const {
3063 print_thread_state_on(tty);
3064 }
3065 #endif // PRODUCT
3066
3067 // Called by Threads::print() for VM_PrintThreads operation
3068 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
3069 st->print_raw("\"");
3070 st->print_raw(get_thread_name());
3071 st->print_raw("\" ");
3072 oop thread_oop = threadObj();
3073 if (thread_oop != NULL) {
3074 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
3075 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
3076 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
3077 }
3078 Thread::print_on(st, print_extended_info);
3079 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
3080 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
3081 if (thread_oop != NULL) {
3082 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3083 }
3084 #ifndef PRODUCT
3085 _safepoint_state->print_on(st);
3086 #endif // PRODUCT
3087 if (is_Compiler_thread()) {
3088 CompileTask *task = ((CompilerThread*)this)->task();
3089 if (task != NULL) {
3090 st->print(" Compiling: ");
3091 task->print(st, NULL, true, false);
3092 } else {
3093 st->print(" No compile task");
3094 }
3095 st->cr();
3096 }
3097 }
3098
3099 void JavaThread::print() const { print_on(tty); }
3100
3101 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3102 st->print("%s", get_thread_name_string(buf, buflen));
3103 }
3104
3105 // Called by fatal error handler. The difference between this and
3106 // JavaThread::print() is that we can't grab lock or allocate memory.
3107 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3108 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3109 oop thread_obj = threadObj();
3110 if (thread_obj != NULL) {
3111 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3112 }
3113 st->print(" [");
3114 st->print("%s", _get_thread_state_name(_thread_state));
3115 if (osthread()) {
3116 st->print(", id=%d", osthread()->thread_id());
3117 }
3118 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3119 p2i(stack_end()), p2i(stack_base()));
3120 st->print("]");
3121
3122 ThreadsSMRSupport::print_info_on(this, st);
3123 return;
3124 }
3125
3126 // Verification
3127
3128 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3129
3130 void JavaThread::verify() {
3131 // Verify oops in the thread.
3132 oops_do(&VerifyOopClosure::verify_oop, NULL);
3133
3134 // Verify the stack frames.
3135 frames_do(frame_verify);
3136 }
3137
3138 // CR 6300358 (sub-CR 2137150)
3139 // Most callers of this method assume that it can't return NULL but a
3140 // thread may not have a name whilst it is in the process of attaching to
3141 // the VM - see CR 6412693, and there are places where a JavaThread can be
3142 // seen prior to having it's threadObj set (eg JNI attaching threads and
3143 // if vm exit occurs during initialization). These cases can all be accounted
3144 // for such that this method never returns NULL.
3145 const char* JavaThread::get_thread_name() const {
3146 #ifdef ASSERT
3147 // early safepoints can hit while current thread does not yet have TLS
3148 if (!SafepointSynchronize::is_at_safepoint()) {
3149 Thread *cur = Thread::current();
3150 if (!(cur->is_Java_thread() && cur == this)) {
3151 // Current JavaThreads are allowed to get their own name without
3152 // the Threads_lock.
3153 assert_locked_or_safepoint(Threads_lock);
3154 }
3155 }
3156 #endif // ASSERT
3157 return get_thread_name_string();
3158 }
3159
3160 // Returns a non-NULL representation of this thread's name, or a suitable
3161 // descriptive string if there is no set name
3162 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3163 const char* name_str;
3164 oop thread_obj = threadObj();
3165 if (thread_obj != NULL) {
3166 oop name = java_lang_Thread::name(thread_obj);
3167 if (name != NULL) {
3168 if (buf == NULL) {
3169 name_str = java_lang_String::as_utf8_string(name);
3170 } else {
3171 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3172 }
3173 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3174 name_str = "<no-name - thread is attaching>";
3175 } else {
3176 name_str = Thread::name();
3177 }
3178 } else {
3179 name_str = Thread::name();
3180 }
3181 assert(name_str != NULL, "unexpected NULL thread name");
3182 return name_str;
3183 }
3184
3185
3186 const char* JavaThread::get_threadgroup_name() const {
3187 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3188 oop thread_obj = threadObj();
3189 if (thread_obj != NULL) {
3190 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3191 if (thread_group != NULL) {
3192 // ThreadGroup.name can be null
3193 return java_lang_ThreadGroup::name(thread_group);
3194 }
3195 }
3196 return NULL;
3197 }
3198
3199 const char* JavaThread::get_parent_name() const {
3200 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3201 oop thread_obj = threadObj();
3202 if (thread_obj != NULL) {
3203 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3204 if (thread_group != NULL) {
3205 oop parent = java_lang_ThreadGroup::parent(thread_group);
3206 if (parent != NULL) {
3207 // ThreadGroup.name can be null
3208 return java_lang_ThreadGroup::name(parent);
3209 }
3210 }
3211 }
3212 return NULL;
3213 }
3214
3215 ThreadPriority JavaThread::java_priority() const {
3216 oop thr_oop = threadObj();
3217 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3218 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3219 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3220 return priority;
3221 }
3222
3223 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3224
3225 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3226 // Link Java Thread object <-> C++ Thread
3227
3228 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3229 // and put it into a new Handle. The Handle "thread_oop" can then
3230 // be used to pass the C++ thread object to other methods.
3231
3232 // Set the Java level thread object (jthread) field of the
3233 // new thread (a JavaThread *) to C++ thread object using the
3234 // "thread_oop" handle.
3235
3236 // Set the thread field (a JavaThread *) of the
3237 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3238
3239 Handle thread_oop(Thread::current(),
3240 JNIHandles::resolve_non_null(jni_thread));
3241 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3242 "must be initialized");
3243 set_threadObj(thread_oop());
3244 java_lang_Thread::set_thread(thread_oop(), this);
3245
3246 if (prio == NoPriority) {
3247 prio = java_lang_Thread::priority(thread_oop());
3248 assert(prio != NoPriority, "A valid priority should be present");
3249 }
3250
3251 // Push the Java priority down to the native thread; needs Threads_lock
3252 Thread::set_priority(this, prio);
3253
3254 // Add the new thread to the Threads list and set it in motion.
3255 // We must have threads lock in order to call Threads::add.
3256 // It is crucial that we do not block before the thread is
3257 // added to the Threads list for if a GC happens, then the java_thread oop
3258 // will not be visited by GC.
3259 Threads::add(this);
3260 }
3261
3262 oop JavaThread::current_park_blocker() {
3263 // Support for JSR-166 locks
3264 oop thread_oop = threadObj();
3265 if (thread_oop != NULL) {
3266 return java_lang_Thread::park_blocker(thread_oop);
3267 }
3268 return NULL;
3269 }
3270
3271
3272 void JavaThread::print_stack_on(outputStream* st) {
3273 if (!has_last_Java_frame()) return;
3274 ResourceMark rm;
3275 HandleMark hm;
3276
3277 RegisterMap reg_map(this);
3278 vframe* start_vf = last_java_vframe(®_map);
3279 int count = 0;
3280 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3281 if (f->is_java_frame()) {
3282 javaVFrame* jvf = javaVFrame::cast(f);
3283 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3284
3285 // Print out lock information
3286 if (JavaMonitorsInStackTrace) {
3287 jvf->print_lock_info_on(st, count);
3288 }
3289 } else {
3290 // Ignore non-Java frames
3291 }
3292
3293 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3294 count++;
3295 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3296 }
3297 }
3298
3299
3300 // JVMTI PopFrame support
3301 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3302 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3303 if (in_bytes(size_in_bytes) != 0) {
3304 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3305 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3306 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3307 }
3308 }
3309
3310 void* JavaThread::popframe_preserved_args() {
3311 return _popframe_preserved_args;
3312 }
3313
3314 ByteSize JavaThread::popframe_preserved_args_size() {
3315 return in_ByteSize(_popframe_preserved_args_size);
3316 }
3317
3318 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3319 int sz = in_bytes(popframe_preserved_args_size());
3320 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3321 return in_WordSize(sz / wordSize);
3322 }
3323
3324 void JavaThread::popframe_free_preserved_args() {
3325 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3326 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3327 _popframe_preserved_args = NULL;
3328 _popframe_preserved_args_size = 0;
3329 }
3330
3331 #ifndef PRODUCT
3332
3333 void JavaThread::trace_frames() {
3334 tty->print_cr("[Describe stack]");
3335 int frame_no = 1;
3336 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3337 tty->print(" %d. ", frame_no++);
3338 fst.current()->print_value_on(tty, this);
3339 tty->cr();
3340 }
3341 }
3342
3343 class PrintAndVerifyOopClosure: public OopClosure {
3344 protected:
3345 template <class T> inline void do_oop_work(T* p) {
3346 oop obj = RawAccess<>::oop_load(p);
3347 if (obj == NULL) return;
3348 tty->print(INTPTR_FORMAT ": ", p2i(p));
3349 if (oopDesc::is_oop_or_null(obj)) {
3350 if (obj->is_objArray()) {
3351 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3352 } else {
3353 obj->print();
3354 }
3355 } else {
3356 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3357 }
3358 tty->cr();
3359 }
3360 public:
3361 virtual void do_oop(oop* p) { do_oop_work(p); }
3362 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3363 };
3364
3365
3366 static void oops_print(frame* f, const RegisterMap *map) {
3367 PrintAndVerifyOopClosure print;
3368 f->print_value();
3369 f->oops_do(&print, NULL, (RegisterMap*)map);
3370 }
3371
3372 // Print our all the locations that contain oops and whether they are
3373 // valid or not. This useful when trying to find the oldest frame
3374 // where an oop has gone bad since the frame walk is from youngest to
3375 // oldest.
3376 void JavaThread::trace_oops() {
3377 tty->print_cr("[Trace oops]");
3378 frames_do(oops_print);
3379 }
3380
3381
3382 #ifdef ASSERT
3383 // Print or validate the layout of stack frames
3384 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3385 ResourceMark rm;
3386 PRESERVE_EXCEPTION_MARK;
3387 FrameValues values;
3388 int frame_no = 0;
3389 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3390 fst.current()->describe(values, ++frame_no);
3391 if (depth == frame_no) break;
3392 }
3393 if (validate_only) {
3394 values.validate();
3395 } else {
3396 tty->print_cr("[Describe stack layout]");
3397 values.print(this);
3398 }
3399 }
3400 #endif
3401
3402 void JavaThread::trace_stack_from(vframe* start_vf) {
3403 ResourceMark rm;
3404 int vframe_no = 1;
3405 for (vframe* f = start_vf; f; f = f->sender()) {
3406 if (f->is_java_frame()) {
3407 javaVFrame::cast(f)->print_activation(vframe_no++);
3408 } else {
3409 f->print();
3410 }
3411 if (vframe_no > StackPrintLimit) {
3412 tty->print_cr("...<more frames>...");
3413 return;
3414 }
3415 }
3416 }
3417
3418
3419 void JavaThread::trace_stack() {
3420 if (!has_last_Java_frame()) return;
3421 ResourceMark rm;
3422 HandleMark hm;
3423 RegisterMap reg_map(this);
3424 trace_stack_from(last_java_vframe(®_map));
3425 }
3426
3427
3428 #endif // PRODUCT
3429
3430
3431 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3432 assert(reg_map != NULL, "a map must be given");
3433 frame f = last_frame();
3434 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3435 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3436 }
3437 return NULL;
3438 }
3439
3440
3441 Klass* JavaThread::security_get_caller_class(int depth) {
3442 vframeStream vfst(this);
3443 vfst.security_get_caller_frame(depth);
3444 if (!vfst.at_end()) {
3445 return vfst.method()->method_holder();
3446 }
3447 return NULL;
3448 }
3449
3450 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3451 assert(thread->is_Compiler_thread(), "must be compiler thread");
3452 CompileBroker::compiler_thread_loop();
3453 }
3454
3455 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3456 NMethodSweeper::sweeper_loop();
3457 }
3458
3459 // Create a CompilerThread
3460 CompilerThread::CompilerThread(CompileQueue* queue,
3461 CompilerCounters* counters)
3462 : JavaThread(&compiler_thread_entry) {
3463 _env = NULL;
3464 _log = NULL;
3465 _task = NULL;
3466 _queue = queue;
3467 _counters = counters;
3468 _buffer_blob = NULL;
3469 _compiler = NULL;
3470
3471 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3472 resource_area()->bias_to(mtCompiler);
3473
3474 #ifndef PRODUCT
3475 _ideal_graph_printer = NULL;
3476 #endif
3477 }
3478
3479 CompilerThread::~CompilerThread() {
3480 // Delete objects which were allocated on heap.
3481 delete _counters;
3482 }
3483
3484 bool CompilerThread::can_call_java() const {
3485 return _compiler != NULL && _compiler->is_jvmci();
3486 }
3487
3488 // Create sweeper thread
3489 CodeCacheSweeperThread::CodeCacheSweeperThread()
3490 : JavaThread(&sweeper_thread_entry) {
3491 _scanned_compiled_method = NULL;
3492 }
3493
3494 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3495 JavaThread::oops_do(f, cf);
3496 if (_scanned_compiled_method != NULL && cf != NULL) {
3497 // Safepoints can occur when the sweeper is scanning an nmethod so
3498 // process it here to make sure it isn't unloaded in the middle of
3499 // a scan.
3500 cf->do_code_blob(_scanned_compiled_method);
3501 }
3502 }
3503
3504 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3505 JavaThread::nmethods_do(cf);
3506 if (_scanned_compiled_method != NULL && cf != NULL) {
3507 // Safepoints can occur when the sweeper is scanning an nmethod so
3508 // process it here to make sure it isn't unloaded in the middle of
3509 // a scan.
3510 cf->do_code_blob(_scanned_compiled_method);
3511 }
3512 }
3513
3514
3515 // ======= Threads ========
3516
3517 // The Threads class links together all active threads, and provides
3518 // operations over all threads. It is protected by the Threads_lock,
3519 // which is also used in other global contexts like safepointing.
3520 // ThreadsListHandles are used to safely perform operations on one
3521 // or more threads without the risk of the thread exiting during the
3522 // operation.
3523 //
3524 // Note: The Threads_lock is currently more widely used than we
3525 // would like. We are actively migrating Threads_lock uses to other
3526 // mechanisms in order to reduce Threads_lock contention.
3527
3528 int Threads::_number_of_threads = 0;
3529 int Threads::_number_of_non_daemon_threads = 0;
3530 int Threads::_return_code = 0;
3531 uintx Threads::_thread_claim_token = 1; // Never zero.
3532 size_t JavaThread::_stack_size_at_create = 0;
3533
3534 #ifdef ASSERT
3535 bool Threads::_vm_complete = false;
3536 #endif
3537
3538 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3539 Prefetch::read((void*)addr, prefetch_interval);
3540 return *addr;
3541 }
3542
3543 // Possibly the ugliest for loop the world has seen. C++ does not allow
3544 // multiple types in the declaration section of the for loop. In this case
3545 // we are only dealing with pointers and hence can cast them. It looks ugly
3546 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3547 #define DO_JAVA_THREADS(LIST, X) \
3548 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3549 *MACRO_list = (JavaThread*)(LIST), \
3550 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3551 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3552 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3553 MACRO_current_p != MACRO_end; \
3554 MACRO_current_p++, \
3555 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3556
3557 // All JavaThreads
3558 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3559
3560 // All NonJavaThreads (i.e., every non-JavaThread in the system).
3561 void Threads::non_java_threads_do(ThreadClosure* tc) {
3562 NoSafepointVerifier nsv(!SafepointSynchronize::is_at_safepoint(), false);
3563 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
3564 tc->do_thread(njti.current());
3565 }
3566 }
3567
3568 // All JavaThreads
3569 void Threads::java_threads_do(ThreadClosure* tc) {
3570 assert_locked_or_safepoint(Threads_lock);
3571 // ALL_JAVA_THREADS iterates through all JavaThreads.
3572 ALL_JAVA_THREADS(p) {
3573 tc->do_thread(p);
3574 }
3575 }
3576
3577 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3578 assert_locked_or_safepoint(Threads_lock);
3579 java_threads_do(tc);
3580 tc->do_thread(VMThread::vm_thread());
3581 }
3582
3583 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3584 void Threads::threads_do(ThreadClosure* tc) {
3585 assert_locked_or_safepoint(Threads_lock);
3586 java_threads_do(tc);
3587 non_java_threads_do(tc);
3588 }
3589
3590 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3591 uintx claim_token = Threads::thread_claim_token();
3592 ALL_JAVA_THREADS(p) {
3593 if (p->claim_threads_do(is_par, claim_token)) {
3594 tc->do_thread(p);
3595 }
3596 }
3597 VMThread* vmt = VMThread::vm_thread();
3598 if (vmt->claim_threads_do(is_par, claim_token)) {
3599 tc->do_thread(vmt);
3600 }
3601 }
3602
3603 // The system initialization in the library has three phases.
3604 //
3605 // Phase 1: java.lang.System class initialization
3606 // java.lang.System is a primordial class loaded and initialized
3607 // by the VM early during startup. java.lang.System.<clinit>
3608 // only does registerNatives and keeps the rest of the class
3609 // initialization work later until thread initialization completes.
3610 //
3611 // System.initPhase1 initializes the system properties, the static
3612 // fields in, out, and err. Set up java signal handlers, OS-specific
3613 // system settings, and thread group of the main thread.
3614 static void call_initPhase1(TRAPS) {
3615 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3616 JavaValue result(T_VOID);
3617 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3618 vmSymbols::void_method_signature(), CHECK);
3619 }
3620
3621 // Phase 2. Module system initialization
3622 // This will initialize the module system. Only java.base classes
3623 // can be loaded until phase 2 completes.
3624 //
3625 // Call System.initPhase2 after the compiler initialization and jsr292
3626 // classes get initialized because module initialization runs a lot of java
3627 // code, that for performance reasons, should be compiled. Also, this will
3628 // enable the startup code to use lambda and other language features in this
3629 // phase and onward.
3630 //
3631 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3632 static void call_initPhase2(TRAPS) {
3633 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3634
3635 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3636
3637 JavaValue result(T_INT);
3638 JavaCallArguments args;
3639 args.push_int(DisplayVMOutputToStderr);
3640 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3641 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3642 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3643 if (result.get_jint() != JNI_OK) {
3644 vm_exit_during_initialization(); // no message or exception
3645 }
3646
3647 universe_post_module_init();
3648 }
3649
3650 // Phase 3. final setup - set security manager, system class loader and TCCL
3651 //
3652 // This will instantiate and set the security manager, set the system class
3653 // loader as well as the thread context class loader. The security manager
3654 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3655 // other modules or the application's classpath.
3656 static void call_initPhase3(TRAPS) {
3657 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3658 JavaValue result(T_VOID);
3659 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3660 vmSymbols::void_method_signature(), CHECK);
3661 }
3662
3663 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3664 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3665
3666 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3667 create_vm_init_libraries();
3668 }
3669
3670 initialize_class(vmSymbols::java_lang_String(), CHECK);
3671
3672 // Inject CompactStrings value after the static initializers for String ran.
3673 java_lang_String::set_compact_strings(CompactStrings);
3674
3675 // Initialize java_lang.System (needed before creating the thread)
3676 initialize_class(vmSymbols::java_lang_System(), CHECK);
3677 // The VM creates & returns objects of this class. Make sure it's initialized.
3678 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3679 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3680 Handle thread_group = create_initial_thread_group(CHECK);
3681 Universe::set_main_thread_group(thread_group());
3682 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3683 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3684 main_thread->set_threadObj(thread_object);
3685
3686 // Set thread status to running since main thread has
3687 // been started and running.
3688 java_lang_Thread::set_thread_status(thread_object,
3689 java_lang_Thread::RUNNABLE);
3690
3691 // The VM creates objects of this class.
3692 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3693
3694 #ifdef ASSERT
3695 InstanceKlass *k = SystemDictionary::UnsafeConstants_klass();
3696 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
3697 #endif
3698
3699 // initialize the hardware-specific constants needed by Unsafe
3700 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
3701 jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
3702
3703 // The VM preresolves methods to these classes. Make sure that they get initialized
3704 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3705 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3706
3707 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3708 call_initPhase1(CHECK);
3709
3710 // get the Java runtime name after java.lang.System is initialized
3711 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3712 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3713
3714 // an instance of OutOfMemory exception has been allocated earlier
3715 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3716 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3717 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3718 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3719 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3720 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3721 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3722 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3723 }
3724
3725 void Threads::initialize_jsr292_core_classes(TRAPS) {
3726 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3727
3728 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3729 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3730 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3731 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3732 }
3733
3734 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3735 extern void JDK_Version_init();
3736
3737 // Preinitialize version info.
3738 VM_Version::early_initialize();
3739
3740 // Check version
3741 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3742
3743 // Initialize library-based TLS
3744 ThreadLocalStorage::init();
3745
3746 // Initialize the output stream module
3747 ostream_init();
3748
3749 // Process java launcher properties.
3750 Arguments::process_sun_java_launcher_properties(args);
3751
3752 // Initialize the os module
3753 os::init();
3754
3755 // Record VM creation timing statistics
3756 TraceVmCreationTime create_vm_timer;
3757 create_vm_timer.start();
3758
3759 // Initialize system properties.
3760 Arguments::init_system_properties();
3761
3762 // So that JDK version can be used as a discriminator when parsing arguments
3763 JDK_Version_init();
3764
3765 // Update/Initialize System properties after JDK version number is known
3766 Arguments::init_version_specific_system_properties();
3767
3768 // Make sure to initialize log configuration *before* parsing arguments
3769 LogConfiguration::initialize(create_vm_timer.begin_time());
3770
3771 // Parse arguments
3772 // Note: this internally calls os::init_container_support()
3773 jint parse_result = Arguments::parse(args);
3774 if (parse_result != JNI_OK) return parse_result;
3775
3776 os::init_before_ergo();
3777
3778 jint ergo_result = Arguments::apply_ergo();
3779 if (ergo_result != JNI_OK) return ergo_result;
3780
3781 // Final check of all ranges after ergonomics which may change values.
3782 if (!JVMFlagRangeList::check_ranges()) {
3783 return JNI_EINVAL;
3784 }
3785
3786 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3787 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo);
3788 if (!constraint_result) {
3789 return JNI_EINVAL;
3790 }
3791
3792 JVMFlagWriteableList::mark_startup();
3793
3794 if (PauseAtStartup) {
3795 os::pause();
3796 }
3797
3798 HOTSPOT_VM_INIT_BEGIN();
3799
3800 // Timing (must come after argument parsing)
3801 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3802
3803 // Initialize the os module after parsing the args
3804 jint os_init_2_result = os::init_2();
3805 if (os_init_2_result != JNI_OK) return os_init_2_result;
3806
3807 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3808 // Initialize assert poison page mechanism.
3809 if (ShowRegistersOnAssert) {
3810 initialize_assert_poison();
3811 }
3812 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3813
3814 SafepointMechanism::initialize();
3815
3816 jint adjust_after_os_result = Arguments::adjust_after_os();
3817 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3818
3819 // Initialize output stream logging
3820 ostream_init_log();
3821
3822 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3823 // Must be before create_vm_init_agents()
3824 if (Arguments::init_libraries_at_startup()) {
3825 convert_vm_init_libraries_to_agents();
3826 }
3827
3828 // Launch -agentlib/-agentpath and converted -Xrun agents
3829 if (Arguments::init_agents_at_startup()) {
3830 create_vm_init_agents();
3831 }
3832
3833 // Initialize Threads state
3834 _number_of_threads = 0;
3835 _number_of_non_daemon_threads = 0;
3836
3837 // Initialize global data structures and create system classes in heap
3838 vm_init_globals();
3839
3840 #if INCLUDE_JVMCI
3841 if (JVMCICounterSize > 0) {
3842 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
3843 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3844 } else {
3845 JavaThread::_jvmci_old_thread_counters = NULL;
3846 }
3847 #endif // INCLUDE_JVMCI
3848
3849 // Attach the main thread to this os thread
3850 JavaThread* main_thread = new JavaThread();
3851 main_thread->set_thread_state(_thread_in_vm);
3852 main_thread->initialize_thread_current();
3853 // must do this before set_active_handles
3854 main_thread->record_stack_base_and_size();
3855 main_thread->register_thread_stack_with_NMT();
3856 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3857
3858 if (!main_thread->set_as_starting_thread()) {
3859 vm_shutdown_during_initialization(
3860 "Failed necessary internal allocation. Out of swap space");
3861 main_thread->smr_delete();
3862 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3863 return JNI_ENOMEM;
3864 }
3865
3866 // Enable guard page *after* os::create_main_thread(), otherwise it would
3867 // crash Linux VM, see notes in os_linux.cpp.
3868 main_thread->create_stack_guard_pages();
3869
3870 // Initialize Java-Level synchronization subsystem
3871 ObjectMonitor::Initialize();
3872
3873 // Initialize global modules
3874 jint status = init_globals();
3875 if (status != JNI_OK) {
3876 main_thread->smr_delete();
3877 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3878 return status;
3879 }
3880
3881 JFR_ONLY(Jfr::on_vm_init();)
3882
3883 // Should be done after the heap is fully created
3884 main_thread->cache_global_variables();
3885
3886 HandleMark hm;
3887
3888 { MutexLocker mu(Threads_lock);
3889 Threads::add(main_thread);
3890 }
3891
3892 // Any JVMTI raw monitors entered in onload will transition into
3893 // real raw monitor. VM is setup enough here for raw monitor enter.
3894 JvmtiExport::transition_pending_onload_raw_monitors();
3895
3896 // Create the VMThread
3897 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3898
3899 VMThread::create();
3900 Thread* vmthread = VMThread::vm_thread();
3901
3902 if (!os::create_thread(vmthread, os::vm_thread)) {
3903 vm_exit_during_initialization("Cannot create VM thread. "
3904 "Out of system resources.");
3905 }
3906
3907 // Wait for the VM thread to become ready, and VMThread::run to initialize
3908 // Monitors can have spurious returns, must always check another state flag
3909 {
3910 MonitorLocker ml(Notify_lock);
3911 os::start_thread(vmthread);
3912 while (vmthread->active_handles() == NULL) {
3913 ml.wait();
3914 }
3915 }
3916 }
3917
3918 assert(Universe::is_fully_initialized(), "not initialized");
3919 if (VerifyDuringStartup) {
3920 // Make sure we're starting with a clean slate.
3921 VM_Verify verify_op;
3922 VMThread::execute(&verify_op);
3923 }
3924
3925 // We need this to update the java.vm.info property in case any flags used
3926 // to initially define it have been changed. This is needed for both CDS and
3927 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info
3928 // is initially computed. See Abstract_VM_Version::vm_info_string().
3929 // This update must happen before we initialize the java classes, but
3930 // after any initialization logic that might modify the flags.
3931 Arguments::update_vm_info_property(VM_Version::vm_info_string());
3932
3933 Thread* THREAD = Thread::current();
3934
3935 // Always call even when there are not JVMTI environments yet, since environments
3936 // may be attached late and JVMTI must track phases of VM execution
3937 JvmtiExport::enter_early_start_phase();
3938
3939 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3940 JvmtiExport::post_early_vm_start();
3941
3942 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3943
3944 quicken_jni_functions();
3945
3946 // No more stub generation allowed after that point.
3947 StubCodeDesc::freeze();
3948
3949 // Set flag that basic initialization has completed. Used by exceptions and various
3950 // debug stuff, that does not work until all basic classes have been initialized.
3951 set_init_completed();
3952
3953 LogConfiguration::post_initialize();
3954 Metaspace::post_initialize();
3955
3956 HOTSPOT_VM_INIT_END();
3957
3958 // record VM initialization completion time
3959 #if INCLUDE_MANAGEMENT
3960 Management::record_vm_init_completed();
3961 #endif // INCLUDE_MANAGEMENT
3962
3963 // Signal Dispatcher needs to be started before VMInit event is posted
3964 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3965
3966 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3967 if (!DisableAttachMechanism) {
3968 AttachListener::vm_start();
3969 if (StartAttachListener || AttachListener::init_at_startup()) {
3970 AttachListener::init();
3971 }
3972 }
3973
3974 // Launch -Xrun agents
3975 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3976 // back-end can launch with -Xdebug -Xrunjdwp.
3977 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3978 create_vm_init_libraries();
3979 }
3980
3981 if (CleanChunkPoolAsync) {
3982 Chunk::start_chunk_pool_cleaner_task();
3983 }
3984
3985 // initialize compiler(s)
3986 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3987 #if INCLUDE_JVMCI
3988 bool force_JVMCI_intialization = false;
3989 if (EnableJVMCI) {
3990 // Initialize JVMCI eagerly when it is explicitly requested.
3991 // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
3992 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
3993
3994 if (!force_JVMCI_intialization) {
3995 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3996 // compilations via JVMCI will not actually block until JVMCI is initialized.
3997 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3998 }
3999 }
4000 #endif
4001 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
4002 // Postpone completion of compiler initialization to after JVMCI
4003 // is initialized to avoid timeouts of blocking compilations.
4004 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
4005 CompileBroker::compilation_init_phase2();
4006 }
4007 #endif
4008
4009 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
4010 // It is done after compilers are initialized, because otherwise compilations of
4011 // signature polymorphic MH intrinsics can be missed
4012 // (see SystemDictionary::find_method_handle_intrinsic).
4013 initialize_jsr292_core_classes(CHECK_JNI_ERR);
4014
4015 // This will initialize the module system. Only java.base classes can be
4016 // loaded until phase 2 completes
4017 call_initPhase2(CHECK_JNI_ERR);
4018
4019 // Always call even when there are not JVMTI environments yet, since environments
4020 // may be attached late and JVMTI must track phases of VM execution
4021 JvmtiExport::enter_start_phase();
4022
4023 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
4024 JvmtiExport::post_vm_start();
4025
4026 // Final system initialization including security manager and system class loader
4027 call_initPhase3(CHECK_JNI_ERR);
4028
4029 // cache the system and platform class loaders
4030 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
4031
4032 #if INCLUDE_CDS
4033 // capture the module path info from the ModuleEntryTable
4034 ClassLoader::initialize_module_path(THREAD);
4035 #endif
4036
4037 #if INCLUDE_JVMCI
4038 if (force_JVMCI_intialization) {
4039 JVMCI::initialize_compiler(CHECK_JNI_ERR);
4040 CompileBroker::compilation_init_phase2();
4041 }
4042 #endif
4043
4044 // Always call even when there are not JVMTI environments yet, since environments
4045 // may be attached late and JVMTI must track phases of VM execution
4046 JvmtiExport::enter_live_phase();
4047
4048 // Make perfmemory accessible
4049 PerfMemory::set_accessible(true);
4050
4051 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
4052 JvmtiExport::post_vm_initialized();
4053
4054 JFR_ONLY(Jfr::on_vm_start();)
4055
4056 #if INCLUDE_MANAGEMENT
4057 Management::initialize(THREAD);
4058
4059 if (HAS_PENDING_EXCEPTION) {
4060 // management agent fails to start possibly due to
4061 // configuration problem and is responsible for printing
4062 // stack trace if appropriate. Simply exit VM.
4063 vm_exit(1);
4064 }
4065 #endif // INCLUDE_MANAGEMENT
4066
4067 if (MemProfiling) MemProfiler::engage();
4068 StatSampler::engage();
4069 if (CheckJNICalls) JniPeriodicChecker::engage();
4070
4071 BiasedLocking::init();
4072
4073 #if INCLUDE_RTM_OPT
4074 RTMLockingCounters::init();
4075 #endif
4076
4077 call_postVMInitHook(THREAD);
4078 // The Java side of PostVMInitHook.run must deal with all
4079 // exceptions and provide means of diagnosis.
4080 if (HAS_PENDING_EXCEPTION) {
4081 CLEAR_PENDING_EXCEPTION;
4082 }
4083
4084 {
4085 MutexLocker ml(PeriodicTask_lock);
4086 // Make sure the WatcherThread can be started by WatcherThread::start()
4087 // or by dynamic enrollment.
4088 WatcherThread::make_startable();
4089 // Start up the WatcherThread if there are any periodic tasks
4090 // NOTE: All PeriodicTasks should be registered by now. If they
4091 // aren't, late joiners might appear to start slowly (we might
4092 // take a while to process their first tick).
4093 if (PeriodicTask::num_tasks() > 0) {
4094 WatcherThread::start();
4095 }
4096 }
4097
4098 create_vm_timer.end();
4099 #ifdef ASSERT
4100 _vm_complete = true;
4101 #endif
4102
4103 if (DumpSharedSpaces) {
4104 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
4105 ShouldNotReachHere();
4106 }
4107
4108 return JNI_OK;
4109 }
4110
4111 // type for the Agent_OnLoad and JVM_OnLoad entry points
4112 extern "C" {
4113 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
4114 }
4115 // Find a command line agent library and return its entry point for
4116 // -agentlib: -agentpath: -Xrun
4117 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
4118 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
4119 const char *on_load_symbols[],
4120 size_t num_symbol_entries) {
4121 OnLoadEntry_t on_load_entry = NULL;
4122 void *library = NULL;
4123
4124 if (!agent->valid()) {
4125 char buffer[JVM_MAXPATHLEN];
4126 char ebuf[1024] = "";
4127 const char *name = agent->name();
4128 const char *msg = "Could not find agent library ";
4129
4130 // First check to see if agent is statically linked into executable
4131 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
4132 library = agent->os_lib();
4133 } else if (agent->is_absolute_path()) {
4134 library = os::dll_load(name, ebuf, sizeof ebuf);
4135 if (library == NULL) {
4136 const char *sub_msg = " in absolute path, with error: ";
4137 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4138 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4139 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4140 // If we can't find the agent, exit.
4141 vm_exit_during_initialization(buf, NULL);
4142 FREE_C_HEAP_ARRAY(char, buf);
4143 }
4144 } else {
4145 // Try to load the agent from the standard dll directory
4146 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4147 name)) {
4148 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4149 }
4150 if (library == NULL) { // Try the library path directory.
4151 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4152 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4153 }
4154 if (library == NULL) {
4155 const char *sub_msg = " on the library path, with error: ";
4156 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4157
4158 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4159 strlen(ebuf) + strlen(sub_msg2) + 1;
4160 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4161 if (!agent->is_instrument_lib()) {
4162 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4163 } else {
4164 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4165 }
4166 // If we can't find the agent, exit.
4167 vm_exit_during_initialization(buf, NULL);
4168 FREE_C_HEAP_ARRAY(char, buf);
4169 }
4170 }
4171 }
4172 agent->set_os_lib(library);
4173 agent->set_valid();
4174 }
4175
4176 // Find the OnLoad function.
4177 on_load_entry =
4178 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4179 false,
4180 on_load_symbols,
4181 num_symbol_entries));
4182 return on_load_entry;
4183 }
4184
4185 // Find the JVM_OnLoad entry point
4186 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4187 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4188 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4189 }
4190
4191 // Find the Agent_OnLoad entry point
4192 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4193 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4194 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4195 }
4196
4197 // For backwards compatibility with -Xrun
4198 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4199 // treated like -agentpath:
4200 // Must be called before agent libraries are created
4201 void Threads::convert_vm_init_libraries_to_agents() {
4202 AgentLibrary* agent;
4203 AgentLibrary* next;
4204
4205 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4206 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4207 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4208
4209 // If there is an JVM_OnLoad function it will get called later,
4210 // otherwise see if there is an Agent_OnLoad
4211 if (on_load_entry == NULL) {
4212 on_load_entry = lookup_agent_on_load(agent);
4213 if (on_load_entry != NULL) {
4214 // switch it to the agent list -- so that Agent_OnLoad will be called,
4215 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4216 Arguments::convert_library_to_agent(agent);
4217 } else {
4218 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4219 }
4220 }
4221 }
4222 }
4223
4224 // Create agents for -agentlib: -agentpath: and converted -Xrun
4225 // Invokes Agent_OnLoad
4226 // Called very early -- before JavaThreads exist
4227 void Threads::create_vm_init_agents() {
4228 extern struct JavaVM_ main_vm;
4229 AgentLibrary* agent;
4230
4231 JvmtiExport::enter_onload_phase();
4232
4233 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4234 // CDS dumping does not support native JVMTI agent.
4235 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
4236 if (DumpSharedSpaces || DynamicDumpSharedSpaces) {
4237 if(!agent->is_instrument_lib()) {
4238 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
4239 } else if (!AllowArchivingWithJavaAgent) {
4240 vm_exit_during_cds_dumping(
4241 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
4242 }
4243 }
4244
4245 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4246
4247 if (on_load_entry != NULL) {
4248 // Invoke the Agent_OnLoad function
4249 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4250 if (err != JNI_OK) {
4251 vm_exit_during_initialization("agent library failed to init", agent->name());
4252 }
4253 } else {
4254 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4255 }
4256 }
4257
4258 JvmtiExport::enter_primordial_phase();
4259 }
4260
4261 extern "C" {
4262 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4263 }
4264
4265 void Threads::shutdown_vm_agents() {
4266 // Send any Agent_OnUnload notifications
4267 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4268 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4269 extern struct JavaVM_ main_vm;
4270 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4271
4272 // Find the Agent_OnUnload function.
4273 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4274 os::find_agent_function(agent,
4275 false,
4276 on_unload_symbols,
4277 num_symbol_entries));
4278
4279 // Invoke the Agent_OnUnload function
4280 if (unload_entry != NULL) {
4281 JavaThread* thread = JavaThread::current();
4282 ThreadToNativeFromVM ttn(thread);
4283 HandleMark hm(thread);
4284 (*unload_entry)(&main_vm);
4285 }
4286 }
4287 }
4288
4289 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4290 // Invokes JVM_OnLoad
4291 void Threads::create_vm_init_libraries() {
4292 extern struct JavaVM_ main_vm;
4293 AgentLibrary* agent;
4294
4295 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4296 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4297
4298 if (on_load_entry != NULL) {
4299 // Invoke the JVM_OnLoad function
4300 JavaThread* thread = JavaThread::current();
4301 ThreadToNativeFromVM ttn(thread);
4302 HandleMark hm(thread);
4303 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4304 if (err != JNI_OK) {
4305 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4306 }
4307 } else {
4308 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4309 }
4310 }
4311 }
4312
4313
4314 // Last thread running calls java.lang.Shutdown.shutdown()
4315 void JavaThread::invoke_shutdown_hooks() {
4316 HandleMark hm(this);
4317
4318 // We could get here with a pending exception, if so clear it now.
4319 if (this->has_pending_exception()) {
4320 this->clear_pending_exception();
4321 }
4322
4323 EXCEPTION_MARK;
4324 Klass* shutdown_klass =
4325 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4326 THREAD);
4327 if (shutdown_klass != NULL) {
4328 // SystemDictionary::resolve_or_null will return null if there was
4329 // an exception. If we cannot load the Shutdown class, just don't
4330 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4331 // won't be run. Note that if a shutdown hook was registered,
4332 // the Shutdown class would have already been loaded
4333 // (Runtime.addShutdownHook will load it).
4334 JavaValue result(T_VOID);
4335 JavaCalls::call_static(&result,
4336 shutdown_klass,
4337 vmSymbols::shutdown_name(),
4338 vmSymbols::void_method_signature(),
4339 THREAD);
4340 }
4341 CLEAR_PENDING_EXCEPTION;
4342 }
4343
4344 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4345 // the program falls off the end of main(). Another VM exit path is through
4346 // vm_exit() when the program calls System.exit() to return a value or when
4347 // there is a serious error in VM. The two shutdown paths are not exactly
4348 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4349 // and VM_Exit op at VM level.
4350 //
4351 // Shutdown sequence:
4352 // + Shutdown native memory tracking if it is on
4353 // + Wait until we are the last non-daemon thread to execute
4354 // <-- every thing is still working at this moment -->
4355 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4356 // shutdown hooks
4357 // + Call before_exit(), prepare for VM exit
4358 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4359 // currently the only user of this mechanism is File.deleteOnExit())
4360 // > stop StatSampler, watcher thread, CMS threads,
4361 // post thread end and vm death events to JVMTI,
4362 // stop signal thread
4363 // + Call JavaThread::exit(), it will:
4364 // > release JNI handle blocks, remove stack guard pages
4365 // > remove this thread from Threads list
4366 // <-- no more Java code from this thread after this point -->
4367 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4368 // the compiler threads at safepoint
4369 // <-- do not use anything that could get blocked by Safepoint -->
4370 // + Disable tracing at JNI/JVM barriers
4371 // + Set _vm_exited flag for threads that are still running native code
4372 // + Call exit_globals()
4373 // > deletes tty
4374 // > deletes PerfMemory resources
4375 // + Delete this thread
4376 // + Return to caller
4377
4378 bool Threads::destroy_vm() {
4379 JavaThread* thread = JavaThread::current();
4380
4381 #ifdef ASSERT
4382 _vm_complete = false;
4383 #endif
4384 // Wait until we are the last non-daemon thread to execute
4385 { MonitorLocker nu(Threads_lock);
4386 while (Threads::number_of_non_daemon_threads() > 1)
4387 // This wait should make safepoint checks, wait without a timeout,
4388 // and wait as a suspend-equivalent condition.
4389 nu.wait(0, Mutex::_as_suspend_equivalent_flag);
4390 }
4391
4392 EventShutdown e;
4393 if (e.should_commit()) {
4394 e.set_reason("No remaining non-daemon Java threads");
4395 e.commit();
4396 }
4397
4398 // Hang forever on exit if we are reporting an error.
4399 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4400 os::infinite_sleep();
4401 }
4402 os::wait_for_keypress_at_exit();
4403
4404 // run Java level shutdown hooks
4405 thread->invoke_shutdown_hooks();
4406
4407 before_exit(thread);
4408
4409 thread->exit(true);
4410
4411 // Stop VM thread.
4412 {
4413 // 4945125 The vm thread comes to a safepoint during exit.
4414 // GC vm_operations can get caught at the safepoint, and the
4415 // heap is unparseable if they are caught. Grab the Heap_lock
4416 // to prevent this. The GC vm_operations will not be able to
4417 // queue until after the vm thread is dead. After this point,
4418 // we'll never emerge out of the safepoint before the VM exits.
4419
4420 MutexLocker ml(Heap_lock, Mutex::_no_safepoint_check_flag);
4421
4422 VMThread::wait_for_vm_thread_exit();
4423 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4424 VMThread::destroy();
4425 }
4426
4427 // Now, all Java threads are gone except daemon threads. Daemon threads
4428 // running Java code or in VM are stopped by the Safepoint. However,
4429 // daemon threads executing native code are still running. But they
4430 // will be stopped at native=>Java/VM barriers. Note that we can't
4431 // simply kill or suspend them, as it is inherently deadlock-prone.
4432
4433 VM_Exit::set_vm_exited();
4434
4435 // Clean up ideal graph printers after the VMThread has started
4436 // the final safepoint which will block all the Compiler threads.
4437 // Note that this Thread has already logically exited so the
4438 // clean_up() function's use of a JavaThreadIteratorWithHandle
4439 // would be a problem except set_vm_exited() has remembered the
4440 // shutdown thread which is granted a policy exception.
4441 #if defined(COMPILER2) && !defined(PRODUCT)
4442 IdealGraphPrinter::clean_up();
4443 #endif
4444
4445 notify_vm_shutdown();
4446
4447 // exit_globals() will delete tty
4448 exit_globals();
4449
4450 // We are after VM_Exit::set_vm_exited() so we can't call
4451 // thread->smr_delete() or we will block on the Threads_lock.
4452 // Deleting the shutdown thread here is safe because another
4453 // JavaThread cannot have an active ThreadsListHandle for
4454 // this JavaThread.
4455 delete thread;
4456
4457 #if INCLUDE_JVMCI
4458 if (JVMCICounterSize > 0) {
4459 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4460 }
4461 #endif
4462
4463 LogConfiguration::finalize();
4464
4465 return true;
4466 }
4467
4468
4469 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4470 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4471 return is_supported_jni_version(version);
4472 }
4473
4474
4475 jboolean Threads::is_supported_jni_version(jint version) {
4476 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4477 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4478 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4479 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4480 if (version == JNI_VERSION_9) return JNI_TRUE;
4481 if (version == JNI_VERSION_10) return JNI_TRUE;
4482 return JNI_FALSE;
4483 }
4484
4485
4486 void Threads::add(JavaThread* p, bool force_daemon) {
4487 // The threads lock must be owned at this point
4488 assert(Threads_lock->owned_by_self(), "must have threads lock");
4489
4490 BarrierSet::barrier_set()->on_thread_attach(p);
4491
4492 // Once a JavaThread is added to the Threads list, smr_delete() has
4493 // to be used to delete it. Otherwise we can just delete it directly.
4494 p->set_on_thread_list();
4495
4496 _number_of_threads++;
4497 oop threadObj = p->threadObj();
4498 bool daemon = true;
4499 // Bootstrapping problem: threadObj can be null for initial
4500 // JavaThread (or for threads attached via JNI)
4501 if ((!force_daemon) && !is_daemon((threadObj))) {
4502 _number_of_non_daemon_threads++;
4503 daemon = false;
4504 }
4505
4506 ThreadService::add_thread(p, daemon);
4507
4508 // Maintain fast thread list
4509 ThreadsSMRSupport::add_thread(p);
4510
4511 // Possible GC point.
4512 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4513 }
4514
4515 void Threads::remove(JavaThread* p, bool is_daemon) {
4516
4517 // Reclaim the ObjectMonitors from the omInUseList and omFreeList of the moribund thread.
4518 ObjectSynchronizer::omFlush(p);
4519
4520 // Extra scope needed for Thread_lock, so we can check
4521 // that we do not remove thread without safepoint code notice
4522 { MonitorLocker ml(Threads_lock);
4523
4524 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4525
4526 // Maintain fast thread list
4527 ThreadsSMRSupport::remove_thread(p);
4528
4529 _number_of_threads--;
4530 if (!is_daemon) {
4531 _number_of_non_daemon_threads--;
4532
4533 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4534 // on destroy_vm will wake up.
4535 if (number_of_non_daemon_threads() == 1) {
4536 ml.notify_all();
4537 }
4538 }
4539 ThreadService::remove_thread(p, is_daemon);
4540
4541 // Make sure that safepoint code disregard this thread. This is needed since
4542 // the thread might mess around with locks after this point. This can cause it
4543 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4544 // of this thread since it is removed from the queue.
4545 p->set_terminated_value();
4546 } // unlock Threads_lock
4547
4548 // Since Events::log uses a lock, we grab it outside the Threads_lock
4549 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4550 }
4551
4552 // Operations on the Threads list for GC. These are not explicitly locked,
4553 // but the garbage collector must provide a safe context for them to run.
4554 // In particular, these things should never be called when the Threads_lock
4555 // is held by some other thread. (Note: the Safepoint abstraction also
4556 // uses the Threads_lock to guarantee this property. It also makes sure that
4557 // all threads gets blocked when exiting or starting).
4558
4559 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4560 ALL_JAVA_THREADS(p) {
4561 p->oops_do(f, cf);
4562 }
4563 VMThread::vm_thread()->oops_do(f, cf);
4564 }
4565
4566 void Threads::change_thread_claim_token() {
4567 if (++_thread_claim_token == 0) {
4568 // On overflow of the token counter, there is a risk of future
4569 // collisions between a new global token value and a stale token
4570 // for a thread, because not all iterations visit all threads.
4571 // (Though it's pretty much a theoretical concern for non-trivial
4572 // token counter sizes.) To deal with the possibility, reset all
4573 // the thread tokens to zero on global token overflow.
4574 struct ResetClaims : public ThreadClosure {
4575 virtual void do_thread(Thread* t) {
4576 t->claim_threads_do(false, 0);
4577 }
4578 } reset_claims;
4579 Threads::threads_do(&reset_claims);
4580 // On overflow, update the global token to non-zero, to
4581 // avoid the special "never claimed" initial thread value.
4582 _thread_claim_token = 1;
4583 }
4584 }
4585
4586 #ifdef ASSERT
4587 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
4588 const uintx token = t->threads_do_token();
4589 assert(token == expected,
4590 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
4591 UINTX_FORMAT, kind, p2i(t), token, expected);
4592 }
4593
4594 void Threads::assert_all_threads_claimed() {
4595 ALL_JAVA_THREADS(p) {
4596 assert_thread_claimed("Thread", p, _thread_claim_token);
4597 }
4598 assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token);
4599 }
4600 #endif // ASSERT
4601
4602 class ParallelOopsDoThreadClosure : public ThreadClosure {
4603 private:
4604 OopClosure* _f;
4605 CodeBlobClosure* _cf;
4606 public:
4607 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4608 void do_thread(Thread* t) {
4609 t->oops_do(_f, _cf);
4610 }
4611 };
4612
4613 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4614 ParallelOopsDoThreadClosure tc(f, cf);
4615 possibly_parallel_threads_do(is_par, &tc);
4616 }
4617
4618 void Threads::nmethods_do(CodeBlobClosure* cf) {
4619 ALL_JAVA_THREADS(p) {
4620 // This is used by the code cache sweeper to mark nmethods that are active
4621 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4622 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4623 if(!p->is_Code_cache_sweeper_thread()) {
4624 p->nmethods_do(cf);
4625 }
4626 }
4627 }
4628
4629 void Threads::metadata_do(MetadataClosure* f) {
4630 ALL_JAVA_THREADS(p) {
4631 p->metadata_do(f);
4632 }
4633 }
4634
4635 class ThreadHandlesClosure : public ThreadClosure {
4636 void (*_f)(Metadata*);
4637 public:
4638 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4639 virtual void do_thread(Thread* thread) {
4640 thread->metadata_handles_do(_f);
4641 }
4642 };
4643
4644 void Threads::metadata_handles_do(void f(Metadata*)) {
4645 // Only walk the Handles in Thread.
4646 ThreadHandlesClosure handles_closure(f);
4647 threads_do(&handles_closure);
4648 }
4649
4650 // Get count Java threads that are waiting to enter the specified monitor.
4651 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4652 int count,
4653 address monitor) {
4654 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4655
4656 int i = 0;
4657 DO_JAVA_THREADS(t_list, p) {
4658 if (!p->can_call_java()) continue;
4659
4660 address pending = (address)p->current_pending_monitor();
4661 if (pending == monitor) { // found a match
4662 if (i < count) result->append(p); // save the first count matches
4663 i++;
4664 }
4665 }
4666
4667 return result;
4668 }
4669
4670
4671 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4672 address owner) {
4673 // NULL owner means not locked so we can skip the search
4674 if (owner == NULL) return NULL;
4675
4676 DO_JAVA_THREADS(t_list, p) {
4677 // first, see if owner is the address of a Java thread
4678 if (owner == (address)p) return p;
4679 }
4680
4681 // Cannot assert on lack of success here since this function may be
4682 // used by code that is trying to report useful problem information
4683 // like deadlock detection.
4684 if (UseHeavyMonitors) return NULL;
4685
4686 // If we didn't find a matching Java thread and we didn't force use of
4687 // heavyweight monitors, then the owner is the stack address of the
4688 // Lock Word in the owning Java thread's stack.
4689 //
4690 JavaThread* the_owner = NULL;
4691 DO_JAVA_THREADS(t_list, q) {
4692 if (q->is_lock_owned(owner)) {
4693 the_owner = q;
4694 break;
4695 }
4696 }
4697
4698 // cannot assert on lack of success here; see above comment
4699 return the_owner;
4700 }
4701
4702 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4703 void Threads::print_on(outputStream* st, bool print_stacks,
4704 bool internal_format, bool print_concurrent_locks,
4705 bool print_extended_info) {
4706 char buf[32];
4707 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4708
4709 st->print_cr("Full thread dump %s (%s %s):",
4710 VM_Version::vm_name(),
4711 VM_Version::vm_release(),
4712 VM_Version::vm_info_string());
4713 st->cr();
4714
4715 #if INCLUDE_SERVICES
4716 // Dump concurrent locks
4717 ConcurrentLocksDump concurrent_locks;
4718 if (print_concurrent_locks) {
4719 concurrent_locks.dump_at_safepoint();
4720 }
4721 #endif // INCLUDE_SERVICES
4722
4723 ThreadsSMRSupport::print_info_on(st);
4724 st->cr();
4725
4726 ALL_JAVA_THREADS(p) {
4727 ResourceMark rm;
4728 p->print_on(st, print_extended_info);
4729 if (print_stacks) {
4730 if (internal_format) {
4731 p->trace_stack();
4732 } else {
4733 p->print_stack_on(st);
4734 }
4735 }
4736 st->cr();
4737 #if INCLUDE_SERVICES
4738 if (print_concurrent_locks) {
4739 concurrent_locks.print_locks_on(p, st);
4740 }
4741 #endif // INCLUDE_SERVICES
4742 }
4743
4744 VMThread::vm_thread()->print_on(st);
4745 st->cr();
4746 Universe::heap()->print_gc_threads_on(st);
4747 WatcherThread* wt = WatcherThread::watcher_thread();
4748 if (wt != NULL) {
4749 wt->print_on(st);
4750 st->cr();
4751 }
4752
4753 st->flush();
4754 }
4755
4756 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4757 int buflen, bool* found_current) {
4758 if (this_thread != NULL) {
4759 bool is_current = (current == this_thread);
4760 *found_current = *found_current || is_current;
4761 st->print("%s", is_current ? "=>" : " ");
4762
4763 st->print(PTR_FORMAT, p2i(this_thread));
4764 st->print(" ");
4765 this_thread->print_on_error(st, buf, buflen);
4766 st->cr();
4767 }
4768 }
4769
4770 class PrintOnErrorClosure : public ThreadClosure {
4771 outputStream* _st;
4772 Thread* _current;
4773 char* _buf;
4774 int _buflen;
4775 bool* _found_current;
4776 public:
4777 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4778 int buflen, bool* found_current) :
4779 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4780
4781 virtual void do_thread(Thread* thread) {
4782 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4783 }
4784 };
4785
4786 // Threads::print_on_error() is called by fatal error handler. It's possible
4787 // that VM is not at safepoint and/or current thread is inside signal handler.
4788 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4789 // memory (even in resource area), it might deadlock the error handler.
4790 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4791 int buflen) {
4792 ThreadsSMRSupport::print_info_on(st);
4793 st->cr();
4794
4795 bool found_current = false;
4796 st->print_cr("Java Threads: ( => current thread )");
4797 ALL_JAVA_THREADS(thread) {
4798 print_on_error(thread, st, current, buf, buflen, &found_current);
4799 }
4800 st->cr();
4801
4802 st->print_cr("Other Threads:");
4803 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4804 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4805
4806 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4807 Universe::heap()->gc_threads_do(&print_closure);
4808
4809 if (!found_current) {
4810 st->cr();
4811 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4812 current->print_on_error(st, buf, buflen);
4813 st->cr();
4814 }
4815 st->cr();
4816
4817 st->print_cr("Threads with active compile tasks:");
4818 print_threads_compiling(st, buf, buflen);
4819 }
4820
4821 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
4822 ALL_JAVA_THREADS(thread) {
4823 if (thread->is_Compiler_thread()) {
4824 CompilerThread* ct = (CompilerThread*) thread;
4825
4826 // Keep task in local variable for NULL check.
4827 // ct->_task might be set to NULL by concurring compiler thread
4828 // because it completed the compilation. The task is never freed,
4829 // though, just returned to a free list.
4830 CompileTask* task = ct->task();
4831 if (task != NULL) {
4832 thread->print_name_on_error(st, buf, buflen);
4833 st->print(" ");
4834 task->print(st, NULL, short_form, true);
4835 }
4836 }
4837 }
4838 }
4839
4840
4841 // Internal SpinLock and Mutex
4842 // Based on ParkEvent
4843
4844 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4845 //
4846 // We employ SpinLocks _only for low-contention, fixed-length
4847 // short-duration critical sections where we're concerned
4848 // about native mutex_t or HotSpot Mutex:: latency.
4849 // The mux construct provides a spin-then-block mutual exclusion
4850 // mechanism.
4851 //
4852 // Testing has shown that contention on the ListLock guarding gFreeList
4853 // is common. If we implement ListLock as a simple SpinLock it's common
4854 // for the JVM to devolve to yielding with little progress. This is true
4855 // despite the fact that the critical sections protected by ListLock are
4856 // extremely short.
4857 //
4858 // TODO-FIXME: ListLock should be of type SpinLock.
4859 // We should make this a 1st-class type, integrated into the lock
4860 // hierarchy as leaf-locks. Critically, the SpinLock structure
4861 // should have sufficient padding to avoid false-sharing and excessive
4862 // cache-coherency traffic.
4863
4864
4865 typedef volatile int SpinLockT;
4866
4867 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4868 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4869 return; // normal fast-path return
4870 }
4871
4872 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4873 int ctr = 0;
4874 int Yields = 0;
4875 for (;;) {
4876 while (*adr != 0) {
4877 ++ctr;
4878 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4879 if (Yields > 5) {
4880 os::naked_short_sleep(1);
4881 } else {
4882 os::naked_yield();
4883 ++Yields;
4884 }
4885 } else {
4886 SpinPause();
4887 }
4888 }
4889 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4890 }
4891 }
4892
4893 void Thread::SpinRelease(volatile int * adr) {
4894 assert(*adr != 0, "invariant");
4895 OrderAccess::fence(); // guarantee at least release consistency.
4896 // Roach-motel semantics.
4897 // It's safe if subsequent LDs and STs float "up" into the critical section,
4898 // but prior LDs and STs within the critical section can't be allowed
4899 // to reorder or float past the ST that releases the lock.
4900 // Loads and stores in the critical section - which appear in program
4901 // order before the store that releases the lock - must also appear
4902 // before the store that releases the lock in memory visibility order.
4903 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4904 // the ST of 0 into the lock-word which releases the lock, so fence
4905 // more than covers this on all platforms.
4906 *adr = 0;
4907 }
4908
4909 // muxAcquire and muxRelease:
4910 //
4911 // * muxAcquire and muxRelease support a single-word lock-word construct.
4912 // The LSB of the word is set IFF the lock is held.
4913 // The remainder of the word points to the head of a singly-linked list
4914 // of threads blocked on the lock.
4915 //
4916 // * The current implementation of muxAcquire-muxRelease uses its own
4917 // dedicated Thread._MuxEvent instance. If we're interested in
4918 // minimizing the peak number of extant ParkEvent instances then
4919 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4920 // as certain invariants were satisfied. Specifically, care would need
4921 // to be taken with regards to consuming unpark() "permits".
4922 // A safe rule of thumb is that a thread would never call muxAcquire()
4923 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4924 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4925 // consume an unpark() permit intended for monitorenter, for instance.
4926 // One way around this would be to widen the restricted-range semaphore
4927 // implemented in park(). Another alternative would be to provide
4928 // multiple instances of the PlatformEvent() for each thread. One
4929 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4930 //
4931 // * Usage:
4932 // -- Only as leaf locks
4933 // -- for short-term locking only as muxAcquire does not perform
4934 // thread state transitions.
4935 //
4936 // Alternatives:
4937 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4938 // but with parking or spin-then-park instead of pure spinning.
4939 // * Use Taura-Oyama-Yonenzawa locks.
4940 // * It's possible to construct a 1-0 lock if we encode the lockword as
4941 // (List,LockByte). Acquire will CAS the full lockword while Release
4942 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4943 // acquiring threads use timers (ParkTimed) to detect and recover from
4944 // the stranding window. Thread/Node structures must be aligned on 256-byte
4945 // boundaries by using placement-new.
4946 // * Augment MCS with advisory back-link fields maintained with CAS().
4947 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4948 // The validity of the backlinks must be ratified before we trust the value.
4949 // If the backlinks are invalid the exiting thread must back-track through the
4950 // the forward links, which are always trustworthy.
4951 // * Add a successor indication. The LockWord is currently encoded as
4952 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4953 // to provide the usual futile-wakeup optimization.
4954 // See RTStt for details.
4955 //
4956
4957
4958 const intptr_t LOCKBIT = 1;
4959
4960 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4961 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4962 if (w == 0) return;
4963 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4964 return;
4965 }
4966
4967 ParkEvent * const Self = Thread::current()->_MuxEvent;
4968 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4969 for (;;) {
4970 int its = (os::is_MP() ? 100 : 0) + 1;
4971
4972 // Optional spin phase: spin-then-park strategy
4973 while (--its >= 0) {
4974 w = *Lock;
4975 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4976 return;
4977 }
4978 }
4979
4980 Self->reset();
4981 Self->OnList = intptr_t(Lock);
4982 // The following fence() isn't _strictly necessary as the subsequent
4983 // CAS() both serializes execution and ratifies the fetched *Lock value.
4984 OrderAccess::fence();
4985 for (;;) {
4986 w = *Lock;
4987 if ((w & LOCKBIT) == 0) {
4988 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4989 Self->OnList = 0; // hygiene - allows stronger asserts
4990 return;
4991 }
4992 continue; // Interference -- *Lock changed -- Just retry
4993 }
4994 assert(w & LOCKBIT, "invariant");
4995 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4996 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4997 }
4998
4999 while (Self->OnList != 0) {
5000 Self->park();
5001 }
5002 }
5003 }
5004
5005 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
5006 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
5007 if (w == 0) return;
5008 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
5009 return;
5010 }
5011
5012 ParkEvent * ReleaseAfter = NULL;
5013 if (ev == NULL) {
5014 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
5015 }
5016 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
5017 for (;;) {
5018 guarantee(ev->OnList == 0, "invariant");
5019 int its = (os::is_MP() ? 100 : 0) + 1;
5020
5021 // Optional spin phase: spin-then-park strategy
5022 while (--its >= 0) {
5023 w = *Lock;
5024 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
5025 if (ReleaseAfter != NULL) {
5026 ParkEvent::Release(ReleaseAfter);
5027 }
5028 return;
5029 }
5030 }
5031
5032 ev->reset();
5033 ev->OnList = intptr_t(Lock);
5034 // The following fence() isn't _strictly necessary as the subsequent
5035 // CAS() both serializes execution and ratifies the fetched *Lock value.
5036 OrderAccess::fence();
5037 for (;;) {
5038 w = *Lock;
5039 if ((w & LOCKBIT) == 0) {
5040 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
5041 ev->OnList = 0;
5042 // We call ::Release while holding the outer lock, thus
5043 // artificially lengthening the critical section.
5044 // Consider deferring the ::Release() until the subsequent unlock(),
5045 // after we've dropped the outer lock.
5046 if (ReleaseAfter != NULL) {
5047 ParkEvent::Release(ReleaseAfter);
5048 }
5049 return;
5050 }
5051 continue; // Interference -- *Lock changed -- Just retry
5052 }
5053 assert(w & LOCKBIT, "invariant");
5054 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
5055 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
5056 }
5057
5058 while (ev->OnList != 0) {
5059 ev->park();
5060 }
5061 }
5062 }
5063
5064 // Release() must extract a successor from the list and then wake that thread.
5065 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
5066 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
5067 // Release() would :
5068 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
5069 // (B) Extract a successor from the private list "in-hand"
5070 // (C) attempt to CAS() the residual back into *Lock over null.
5071 // If there were any newly arrived threads and the CAS() would fail.
5072 // In that case Release() would detach the RATs, re-merge the list in-hand
5073 // with the RATs and repeat as needed. Alternately, Release() might
5074 // detach and extract a successor, but then pass the residual list to the wakee.
5075 // The wakee would be responsible for reattaching and remerging before it
5076 // competed for the lock.
5077 //
5078 // Both "pop" and DMR are immune from ABA corruption -- there can be
5079 // multiple concurrent pushers, but only one popper or detacher.
5080 // This implementation pops from the head of the list. This is unfair,
5081 // but tends to provide excellent throughput as hot threads remain hot.
5082 // (We wake recently run threads first).
5083 //
5084 // All paths through muxRelease() will execute a CAS.
5085 // Release consistency -- We depend on the CAS in muxRelease() to provide full
5086 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
5087 // executed within the critical section are complete and globally visible before the
5088 // store (CAS) to the lock-word that releases the lock becomes globally visible.
5089 void Thread::muxRelease(volatile intptr_t * Lock) {
5090 for (;;) {
5091 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
5092 assert(w & LOCKBIT, "invariant");
5093 if (w == LOCKBIT) return;
5094 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
5095 assert(List != NULL, "invariant");
5096 assert(List->OnList == intptr_t(Lock), "invariant");
5097 ParkEvent * const nxt = List->ListNext;
5098 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5099
5100 // The following CAS() releases the lock and pops the head element.
5101 // The CAS() also ratifies the previously fetched lock-word value.
5102 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
5103 continue;
5104 }
5105 List->OnList = 0;
5106 OrderAccess::fence();
5107 List->unpark();
5108 return;
5109 }
5110 }
5111
5112
5113 void Threads::verify() {
5114 ALL_JAVA_THREADS(p) {
5115 p->verify();
5116 }
5117 VMThread* thread = VMThread::vm_thread();
5118 if (thread != NULL) thread->verify();
5119 }