1 /*
2 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/moduleEntry.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "classfile/vmSymbols.hpp"
32 #include "code/codeCache.hpp"
33 #include "code/scopeDesc.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "compiler/compileTask.hpp"
36 #include "gc/shared/barrierSet.hpp"
37 #include "gc/shared/gcId.hpp"
38 #include "gc/shared/gcLocker.inline.hpp"
39 #include "gc/shared/workgroup.hpp"
40 #include "interpreter/interpreter.hpp"
41 #include "interpreter/linkResolver.hpp"
42 #include "interpreter/oopMapCache.hpp"
43 #include "jfr/jfrEvents.hpp"
44 #include "jvmtifiles/jvmtiEnv.hpp"
45 #include "logging/log.hpp"
46 #include "logging/logConfiguration.hpp"
47 #include "logging/logStream.hpp"
48 #include "memory/allocation.inline.hpp"
49 #include "memory/metaspaceShared.hpp"
50 #include "memory/oopFactory.hpp"
51 #include "memory/resourceArea.hpp"
52 #include "memory/universe.hpp"
53 #include "oops/access.inline.hpp"
54 #include "oops/instanceKlass.hpp"
55 #include "oops/objArrayOop.hpp"
56 #include "oops/oop.inline.hpp"
57 #include "oops/symbol.hpp"
58 #include "oops/typeArrayOop.inline.hpp"
59 #include "oops/verifyOopClosure.hpp"
60 #include "prims/jvm_misc.hpp"
61 #include "prims/jvmtiExport.hpp"
62 #include "prims/jvmtiThreadState.hpp"
63 #include "runtime/arguments.hpp"
64 #include "runtime/atomic.hpp"
65 #include "runtime/biasedLocking.hpp"
66 #include "runtime/fieldDescriptor.inline.hpp"
67 #include "runtime/flags/jvmFlagConstraintList.hpp"
68 #include "runtime/flags/jvmFlagRangeList.hpp"
69 #include "runtime/flags/jvmFlagWriteableList.hpp"
70 #include "runtime/deoptimization.hpp"
71 #include "runtime/frame.inline.hpp"
72 #include "runtime/handles.inline.hpp"
73 #include "runtime/handshake.hpp"
74 #include "runtime/init.hpp"
75 #include "runtime/interfaceSupport.inline.hpp"
76 #include "runtime/java.hpp"
77 #include "runtime/javaCalls.hpp"
78 #include "runtime/jniHandles.inline.hpp"
79 #include "runtime/jniPeriodicChecker.hpp"
80 #include "runtime/memprofiler.hpp"
81 #include "runtime/mutexLocker.hpp"
82 #include "runtime/objectMonitor.hpp"
83 #include "runtime/orderAccess.hpp"
84 #include "runtime/osThread.hpp"
85 #include "runtime/prefetch.inline.hpp"
86 #include "runtime/safepoint.hpp"
87 #include "runtime/safepointMechanism.inline.hpp"
88 #include "runtime/safepointVerifiers.hpp"
89 #include "runtime/sharedRuntime.hpp"
90 #include "runtime/statSampler.hpp"
91 #include "runtime/stubRoutines.hpp"
92 #include "runtime/sweeper.hpp"
93 #include "runtime/task.hpp"
94 #include "runtime/thread.inline.hpp"
95 #include "runtime/threadCritical.hpp"
96 #include "runtime/threadSMR.inline.hpp"
97 #include "runtime/threadStatisticalInfo.hpp"
98 #include "runtime/timer.hpp"
99 #include "runtime/timerTrace.hpp"
100 #include "runtime/vframe.inline.hpp"
101 #include "runtime/vframeArray.hpp"
102 #include "runtime/vframe_hp.hpp"
103 #include "runtime/vmThread.hpp"
104 #include "runtime/vmOperations.hpp"
105 #include "runtime/vm_version.hpp"
106 #include "services/attachListener.hpp"
107 #include "services/management.hpp"
108 #include "services/memTracker.hpp"
109 #include "services/threadService.hpp"
110 #include "utilities/align.hpp"
111 #include "utilities/copy.hpp"
112 #include "utilities/defaultStream.hpp"
113 #include "utilities/dtrace.hpp"
114 #include "utilities/events.hpp"
115 #include "utilities/macros.hpp"
116 #include "utilities/preserveException.hpp"
117 #include "utilities/singleWriterSynchronizer.hpp"
118 #include "utilities/vmError.hpp"
119 #if INCLUDE_JVMCI
120 #include "jvmci/jvmciCompiler.hpp"
121 #include "jvmci/jvmciRuntime.hpp"
122 #include "logging/logHandle.hpp"
123 #endif
124 #ifdef COMPILER1
125 #include "c1/c1_Compiler.hpp"
126 #endif
127 #ifdef COMPILER2
128 #include "opto/c2compiler.hpp"
129 #include "opto/idealGraphPrinter.hpp"
130 #endif
131 #if INCLUDE_RTM_OPT
132 #include "runtime/rtmLocking.hpp"
133 #endif
134 #if INCLUDE_JFR
135 #include "jfr/jfr.hpp"
136 #endif
137
138 // Initialization after module runtime initialization
139 void universe_post_module_init(); // must happen after call_initPhase2
140
141 #ifdef DTRACE_ENABLED
142
143 // Only bother with this argument setup if dtrace is available
144
145 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
146 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
147
148 #define DTRACE_THREAD_PROBE(probe, javathread) \
149 { \
150 ResourceMark rm(this); \
151 int len = 0; \
152 const char* name = (javathread)->get_thread_name(); \
153 len = strlen(name); \
154 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
155 (char *) name, len, \
156 java_lang_Thread::thread_id((javathread)->threadObj()), \
157 (uintptr_t) (javathread)->osthread()->thread_id(), \
158 java_lang_Thread::is_daemon((javathread)->threadObj())); \
159 }
160
161 #else // ndef DTRACE_ENABLED
162
163 #define DTRACE_THREAD_PROBE(probe, javathread)
164
165 #endif // ndef DTRACE_ENABLED
166
167 #ifndef USE_LIBRARY_BASED_TLS_ONLY
168 // Current thread is maintained as a thread-local variable
169 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
170 #endif
171
172 // ======= Thread ========
173 // Support for forcing alignment of thread objects for biased locking
174 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
175 if (UseBiasedLocking) {
176 const int alignment = markOopDesc::biased_lock_alignment;
177 size_t aligned_size = size + (alignment - sizeof(intptr_t));
178 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
179 : AllocateHeap(aligned_size, flags, CURRENT_PC,
180 AllocFailStrategy::RETURN_NULL);
181 void* aligned_addr = align_up(real_malloc_addr, alignment);
182 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
183 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
184 "JavaThread alignment code overflowed allocated storage");
185 if (aligned_addr != real_malloc_addr) {
186 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
187 p2i(real_malloc_addr),
188 p2i(aligned_addr));
189 }
190 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
191 return aligned_addr;
192 } else {
193 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
194 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
195 }
196 }
197
198 void Thread::operator delete(void* p) {
199 if (UseBiasedLocking) {
200 FreeHeap(((Thread*) p)->_real_malloc_address);
201 } else {
202 FreeHeap(p);
203 }
204 }
205
206 void JavaThread::smr_delete() {
207 if (_on_thread_list) {
208 ThreadsSMRSupport::smr_delete(this);
209 } else {
210 delete this;
211 }
212 }
213
214 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
215 // JavaThread
216
217 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
218
219 Thread::Thread() {
220
221 DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
222
223 // stack and get_thread
224 set_stack_base(NULL);
225 set_stack_size(0);
226 set_self_raw_id(0);
227 set_lgrp_id(-1);
228 DEBUG_ONLY(clear_suspendible_thread();)
229
230 // allocated data structures
231 set_osthread(NULL);
232 set_resource_area(new (mtThread)ResourceArea());
233 DEBUG_ONLY(_current_resource_mark = NULL;)
234 set_handle_area(new (mtThread) HandleArea(NULL));
235 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
236 set_active_handles(NULL);
237 set_free_handle_block(NULL);
238 set_last_handle_mark(NULL);
239 DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
240
241 // This initial value ==> never claimed.
242 _oops_do_parity = 0;
243 _threads_hazard_ptr = NULL;
244 _threads_list_ptr = NULL;
245 _nested_threads_hazard_ptr_cnt = 0;
246 _rcu_counter = 0;
247
248 // the handle mark links itself to last_handle_mark
249 new HandleMark(this);
250
251 // plain initialization
252 debug_only(_owned_locks = NULL;)
253 debug_only(_allow_allocation_count = 0;)
254 NOT_PRODUCT(_allow_safepoint_count = 0;)
255 NOT_PRODUCT(_skip_gcalot = false;)
256 _jvmti_env_iteration_count = 0;
257 set_allocated_bytes(0);
258 _vm_operation_started_count = 0;
259 _vm_operation_completed_count = 0;
260 _current_pending_monitor = NULL;
261 _current_pending_monitor_is_from_java = true;
262 _current_waiting_monitor = NULL;
263 _num_nested_signal = 0;
264 omFreeList = NULL;
265 omFreeCount = 0;
266 omFreeProvision = 32;
267 omInUseList = NULL;
268 omInUseCount = 0;
269 omShouldDeflateIdleMonitors = false;
270
271 #ifdef ASSERT
272 _visited_for_critical_count = false;
273 #endif
274
275 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
276 Monitor::_safepoint_check_sometimes);
277 _suspend_flags = 0;
278
279 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
280 _hashStateX = os::random();
281 _hashStateY = 842502087;
282 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
283 _hashStateW = 273326509;
284
285 _OnTrap = 0;
286 _Stalled = 0;
287 _TypeTag = 0x2BAD;
288
289 // Many of the following fields are effectively final - immutable
290 // Note that nascent threads can't use the Native Monitor-Mutex
291 // construct until the _MutexEvent is initialized ...
292 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
293 // we might instead use a stack of ParkEvents that we could provision on-demand.
294 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
295 // and ::Release()
296 _ParkEvent = ParkEvent::Allocate(this);
297 _SleepEvent = ParkEvent::Allocate(this);
298 _MuxEvent = ParkEvent::Allocate(this);
299
300 #ifdef CHECK_UNHANDLED_OOPS
301 if (CheckUnhandledOops) {
302 _unhandled_oops = new UnhandledOops(this);
303 }
304 #endif // CHECK_UNHANDLED_OOPS
305 #ifdef ASSERT
306 if (UseBiasedLocking) {
307 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
308 assert(this == _real_malloc_address ||
309 this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
310 "bug in forced alignment of thread objects");
311 }
312 #endif // ASSERT
313
314 // Notify the barrier set that a thread is being created. The initial
315 // thread is created before the barrier set is available. The call to
316 // BarrierSet::on_thread_create() for this thread is therefore deferred
317 // to BarrierSet::set_barrier_set().
318 BarrierSet* const barrier_set = BarrierSet::barrier_set();
319 if (barrier_set != NULL) {
320 barrier_set->on_thread_create(this);
321 } else {
322 // Only the main thread should be created before the barrier set
323 // and that happens just before Thread::current is set. No other thread
324 // can attach as the VM is not created yet, so they can't execute this code.
325 // If the main thread creates other threads before the barrier set that is an error.
326 assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
327 }
328 }
329
330 void Thread::initialize_thread_current() {
331 #ifndef USE_LIBRARY_BASED_TLS_ONLY
332 assert(_thr_current == NULL, "Thread::current already initialized");
333 _thr_current = this;
334 #endif
335 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
336 ThreadLocalStorage::set_thread(this);
337 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
338 }
339
340 void Thread::clear_thread_current() {
341 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
342 #ifndef USE_LIBRARY_BASED_TLS_ONLY
343 _thr_current = NULL;
344 #endif
345 ThreadLocalStorage::set_thread(NULL);
346 }
347
348 void Thread::record_stack_base_and_size() {
349 // Note: at this point, Thread object is not yet initialized. Do not rely on
350 // any members being initialized. Do not rely on Thread::current() being set.
351 // If possible, refrain from doing anything which may crash or assert since
352 // quite probably those crash dumps will be useless.
353 set_stack_base(os::current_stack_base());
354 set_stack_size(os::current_stack_size());
355
356 #ifdef SOLARIS
357 if (os::is_primordial_thread()) {
358 os::Solaris::correct_stack_boundaries_for_primordial_thread(this);
359 }
360 #endif
361
362 // Set stack limits after thread is initialized.
363 if (is_Java_thread()) {
364 ((JavaThread*) this)->set_stack_overflow_limit();
365 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
366 }
367 }
368
369 #if INCLUDE_NMT
370 void Thread::register_thread_stack_with_NMT() {
371 MemTracker::record_thread_stack(stack_end(), stack_size());
372 }
373 #endif // INCLUDE_NMT
374
375 void Thread::call_run() {
376 DEBUG_ONLY(_run_state = CALL_RUN;)
377
378 // At this point, Thread object should be fully initialized and
379 // Thread::current() should be set.
380
381 assert(Thread::current_or_null() != NULL, "current thread is unset");
382 assert(Thread::current_or_null() == this, "current thread is wrong");
383
384 // Perform common initialization actions
385
386 register_thread_stack_with_NMT();
387
388 JFR_ONLY(Jfr::on_thread_start(this);)
389
390 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
391 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
392 os::current_thread_id(), p2i(stack_base() - stack_size()),
393 p2i(stack_base()), stack_size()/1024);
394
395 // Perform <ChildClass> initialization actions
396 DEBUG_ONLY(_run_state = PRE_RUN;)
397 this->pre_run();
398
399 // Invoke <ChildClass>::run()
400 DEBUG_ONLY(_run_state = RUN;)
401 this->run();
402 // Returned from <ChildClass>::run(). Thread finished.
403
404 // Perform common tear-down actions
405
406 assert(Thread::current_or_null() != NULL, "current thread is unset");
407 assert(Thread::current_or_null() == this, "current thread is wrong");
408
409 // Perform <ChildClass> tear-down actions
410 DEBUG_ONLY(_run_state = POST_RUN;)
411 this->post_run();
412
413 // Note: at this point the thread object may already have deleted itself,
414 // so from here on do not dereference *this*. Not all thread types currently
415 // delete themselves when they terminate. But no thread should ever be deleted
416 // asynchronously with respect to its termination - that is what _run_state can
417 // be used to check.
418
419 assert(Thread::current_or_null() == NULL, "current thread still present");
420 }
421
422 Thread::~Thread() {
423
424 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
425 // get started due to errors etc. Any active thread should at least reach post_run
426 // before it is deleted (usually in post_run()).
427 assert(_run_state == PRE_CALL_RUN ||
428 _run_state == POST_RUN, "Active Thread deleted before post_run(): "
429 "_run_state=%d", (int)_run_state);
430
431 // Notify the barrier set that a thread is being destroyed. Note that a barrier
432 // set might not be available if we encountered errors during bootstrapping.
433 BarrierSet* const barrier_set = BarrierSet::barrier_set();
434 if (barrier_set != NULL) {
435 barrier_set->on_thread_destroy(this);
436 }
437
438 // stack_base can be NULL if the thread is never started or exited before
439 // record_stack_base_and_size called. Although, we would like to ensure
440 // that all started threads do call record_stack_base_and_size(), there is
441 // not proper way to enforce that.
442 #if INCLUDE_NMT
443 if (_stack_base != NULL) {
444 MemTracker::release_thread_stack(stack_end(), stack_size());
445 #ifdef ASSERT
446 set_stack_base(NULL);
447 #endif
448 }
449 #endif // INCLUDE_NMT
450
451 // deallocate data structures
452 delete resource_area();
453 // since the handle marks are using the handle area, we have to deallocated the root
454 // handle mark before deallocating the thread's handle area,
455 assert(last_handle_mark() != NULL, "check we have an element");
456 delete last_handle_mark();
457 assert(last_handle_mark() == NULL, "check we have reached the end");
458
459 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
460 // We NULL out the fields for good hygiene.
461 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
462 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
463 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
464
465 delete handle_area();
466 delete metadata_handles();
467
468 // SR_handler uses this as a termination indicator -
469 // needs to happen before os::free_thread()
470 delete _SR_lock;
471 _SR_lock = NULL;
472
473 // osthread() can be NULL, if creation of thread failed.
474 if (osthread() != NULL) os::free_thread(osthread());
475
476 // Clear Thread::current if thread is deleting itself and it has not
477 // already been done. This must be done before the memory is deallocated.
478 // Needed to ensure JNI correctly detects non-attached threads.
479 if (this == Thread::current_or_null()) {
480 Thread::clear_thread_current();
481 }
482
483 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
484 }
485
486 #ifdef ASSERT
487 // A JavaThread is considered "dangling" if it is not the current
488 // thread, has been added the Threads list, the system is not at a
489 // safepoint and the Thread is not "protected".
490 //
491 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
492 assert(!thread->is_Java_thread() || Thread::current() == thread ||
493 !((JavaThread *) thread)->on_thread_list() ||
494 SafepointSynchronize::is_at_safepoint() ||
495 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
496 "possibility of dangling Thread pointer");
497 }
498 #endif
499
500 ThreadPriority Thread::get_priority(const Thread* const thread) {
501 ThreadPriority priority;
502 // Can return an error!
503 (void)os::get_priority(thread, priority);
504 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
505 return priority;
506 }
507
508 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
509 debug_only(check_for_dangling_thread_pointer(thread);)
510 // Can return an error!
511 (void)os::set_priority(thread, priority);
512 }
513
514
515 void Thread::start(Thread* thread) {
516 // Start is different from resume in that its safety is guaranteed by context or
517 // being called from a Java method synchronized on the Thread object.
518 if (!DisableStartThread) {
519 if (thread->is_Java_thread()) {
520 // Initialize the thread state to RUNNABLE before starting this thread.
521 // Can not set it after the thread started because we do not know the
522 // exact thread state at that time. It could be in MONITOR_WAIT or
523 // in SLEEPING or some other state.
524 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
525 java_lang_Thread::RUNNABLE);
526 }
527 os::start_thread(thread);
528 }
529 }
530
531 // Enqueue a VM_Operation to do the job for us - sometime later
532 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
533 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
534 VMThread::execute(vm_stop);
535 }
536
537
538 // Check if an external suspend request has completed (or has been
539 // cancelled). Returns true if the thread is externally suspended and
540 // false otherwise.
541 //
542 // The bits parameter returns information about the code path through
543 // the routine. Useful for debugging:
544 //
545 // set in is_ext_suspend_completed():
546 // 0x00000001 - routine was entered
547 // 0x00000010 - routine return false at end
548 // 0x00000100 - thread exited (return false)
549 // 0x00000200 - suspend request cancelled (return false)
550 // 0x00000400 - thread suspended (return true)
551 // 0x00001000 - thread is in a suspend equivalent state (return true)
552 // 0x00002000 - thread is native and walkable (return true)
553 // 0x00004000 - thread is native_trans and walkable (needed retry)
554 //
555 // set in wait_for_ext_suspend_completion():
556 // 0x00010000 - routine was entered
557 // 0x00020000 - suspend request cancelled before loop (return false)
558 // 0x00040000 - thread suspended before loop (return true)
559 // 0x00080000 - suspend request cancelled in loop (return false)
560 // 0x00100000 - thread suspended in loop (return true)
561 // 0x00200000 - suspend not completed during retry loop (return false)
562
563 // Helper class for tracing suspend wait debug bits.
564 //
565 // 0x00000100 indicates that the target thread exited before it could
566 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
567 // 0x00080000 each indicate a cancelled suspend request so they don't
568 // count as wait failures either.
569 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
570
571 class TraceSuspendDebugBits : public StackObj {
572 private:
573 JavaThread * jt;
574 bool is_wait;
575 bool called_by_wait; // meaningful when !is_wait
576 uint32_t * bits;
577
578 public:
579 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
580 uint32_t *_bits) {
581 jt = _jt;
582 is_wait = _is_wait;
583 called_by_wait = _called_by_wait;
584 bits = _bits;
585 }
586
587 ~TraceSuspendDebugBits() {
588 if (!is_wait) {
589 #if 1
590 // By default, don't trace bits for is_ext_suspend_completed() calls.
591 // That trace is very chatty.
592 return;
593 #else
594 if (!called_by_wait) {
595 // If tracing for is_ext_suspend_completed() is enabled, then only
596 // trace calls to it from wait_for_ext_suspend_completion()
597 return;
598 }
599 #endif
600 }
601
602 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
603 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
604 MutexLocker ml(Threads_lock); // needed for get_thread_name()
605 ResourceMark rm;
606
607 tty->print_cr(
608 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
609 jt->get_thread_name(), *bits);
610
611 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
612 }
613 }
614 }
615 };
616 #undef DEBUG_FALSE_BITS
617
618
619 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
620 uint32_t *bits) {
621 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
622
623 bool did_trans_retry = false; // only do thread_in_native_trans retry once
624 bool do_trans_retry; // flag to force the retry
625
626 *bits |= 0x00000001;
627
628 do {
629 do_trans_retry = false;
630
631 if (is_exiting()) {
632 // Thread is in the process of exiting. This is always checked
633 // first to reduce the risk of dereferencing a freed JavaThread.
634 *bits |= 0x00000100;
635 return false;
636 }
637
638 if (!is_external_suspend()) {
639 // Suspend request is cancelled. This is always checked before
640 // is_ext_suspended() to reduce the risk of a rogue resume
641 // confusing the thread that made the suspend request.
642 *bits |= 0x00000200;
643 return false;
644 }
645
646 if (is_ext_suspended()) {
647 // thread is suspended
648 *bits |= 0x00000400;
649 return true;
650 }
651
652 // Now that we no longer do hard suspends of threads running
653 // native code, the target thread can be changing thread state
654 // while we are in this routine:
655 //
656 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
657 //
658 // We save a copy of the thread state as observed at this moment
659 // and make our decision about suspend completeness based on the
660 // copy. This closes the race where the thread state is seen as
661 // _thread_in_native_trans in the if-thread_blocked check, but is
662 // seen as _thread_blocked in if-thread_in_native_trans check.
663 JavaThreadState save_state = thread_state();
664
665 if (save_state == _thread_blocked && is_suspend_equivalent()) {
666 // If the thread's state is _thread_blocked and this blocking
667 // condition is known to be equivalent to a suspend, then we can
668 // consider the thread to be externally suspended. This means that
669 // the code that sets _thread_blocked has been modified to do
670 // self-suspension if the blocking condition releases. We also
671 // used to check for CONDVAR_WAIT here, but that is now covered by
672 // the _thread_blocked with self-suspension check.
673 //
674 // Return true since we wouldn't be here unless there was still an
675 // external suspend request.
676 *bits |= 0x00001000;
677 return true;
678 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
679 // Threads running native code will self-suspend on native==>VM/Java
680 // transitions. If its stack is walkable (should always be the case
681 // unless this function is called before the actual java_suspend()
682 // call), then the wait is done.
683 *bits |= 0x00002000;
684 return true;
685 } else if (!called_by_wait && !did_trans_retry &&
686 save_state == _thread_in_native_trans &&
687 frame_anchor()->walkable()) {
688 // The thread is transitioning from thread_in_native to another
689 // thread state. check_safepoint_and_suspend_for_native_trans()
690 // will force the thread to self-suspend. If it hasn't gotten
691 // there yet we may have caught the thread in-between the native
692 // code check above and the self-suspend. Lucky us. If we were
693 // called by wait_for_ext_suspend_completion(), then it
694 // will be doing the retries so we don't have to.
695 //
696 // Since we use the saved thread state in the if-statement above,
697 // there is a chance that the thread has already transitioned to
698 // _thread_blocked by the time we get here. In that case, we will
699 // make a single unnecessary pass through the logic below. This
700 // doesn't hurt anything since we still do the trans retry.
701
702 *bits |= 0x00004000;
703
704 // Once the thread leaves thread_in_native_trans for another
705 // thread state, we break out of this retry loop. We shouldn't
706 // need this flag to prevent us from getting back here, but
707 // sometimes paranoia is good.
708 did_trans_retry = true;
709
710 // We wait for the thread to transition to a more usable state.
711 for (int i = 1; i <= SuspendRetryCount; i++) {
712 // We used to do an "os::yield_all(i)" call here with the intention
713 // that yielding would increase on each retry. However, the parameter
714 // is ignored on Linux which means the yield didn't scale up. Waiting
715 // on the SR_lock below provides a much more predictable scale up for
716 // the delay. It also provides a simple/direct point to check for any
717 // safepoint requests from the VMThread
718
719 // temporarily drops SR_lock while doing wait with safepoint check
720 // (if we're a JavaThread - the WatcherThread can also call this)
721 // and increase delay with each retry
722 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
723
724 // check the actual thread state instead of what we saved above
725 if (thread_state() != _thread_in_native_trans) {
726 // the thread has transitioned to another thread state so
727 // try all the checks (except this one) one more time.
728 do_trans_retry = true;
729 break;
730 }
731 } // end retry loop
732
733
734 }
735 } while (do_trans_retry);
736
737 *bits |= 0x00000010;
738 return false;
739 }
740
741 // Wait for an external suspend request to complete (or be cancelled).
742 // Returns true if the thread is externally suspended and false otherwise.
743 //
744 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
745 uint32_t *bits) {
746 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
747 false /* !called_by_wait */, bits);
748
749 // local flag copies to minimize SR_lock hold time
750 bool is_suspended;
751 bool pending;
752 uint32_t reset_bits;
753
754 // set a marker so is_ext_suspend_completed() knows we are the caller
755 *bits |= 0x00010000;
756
757 // We use reset_bits to reinitialize the bits value at the top of
758 // each retry loop. This allows the caller to make use of any
759 // unused bits for their own marking purposes.
760 reset_bits = *bits;
761
762 {
763 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
764 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
765 delay, bits);
766 pending = is_external_suspend();
767 }
768 // must release SR_lock to allow suspension to complete
769
770 if (!pending) {
771 // A cancelled suspend request is the only false return from
772 // is_ext_suspend_completed() that keeps us from entering the
773 // retry loop.
774 *bits |= 0x00020000;
775 return false;
776 }
777
778 if (is_suspended) {
779 *bits |= 0x00040000;
780 return true;
781 }
782
783 for (int i = 1; i <= retries; i++) {
784 *bits = reset_bits; // reinit to only track last retry
785
786 // We used to do an "os::yield_all(i)" call here with the intention
787 // that yielding would increase on each retry. However, the parameter
788 // is ignored on Linux which means the yield didn't scale up. Waiting
789 // on the SR_lock below provides a much more predictable scale up for
790 // the delay. It also provides a simple/direct point to check for any
791 // safepoint requests from the VMThread
792
793 {
794 MutexLocker ml(SR_lock());
795 // wait with safepoint check (if we're a JavaThread - the WatcherThread
796 // can also call this) and increase delay with each retry
797 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
798
799 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
800 delay, bits);
801
802 // It is possible for the external suspend request to be cancelled
803 // (by a resume) before the actual suspend operation is completed.
804 // Refresh our local copy to see if we still need to wait.
805 pending = is_external_suspend();
806 }
807
808 if (!pending) {
809 // A cancelled suspend request is the only false return from
810 // is_ext_suspend_completed() that keeps us from staying in the
811 // retry loop.
812 *bits |= 0x00080000;
813 return false;
814 }
815
816 if (is_suspended) {
817 *bits |= 0x00100000;
818 return true;
819 }
820 } // end retry loop
821
822 // thread did not suspend after all our retries
823 *bits |= 0x00200000;
824 return false;
825 }
826
827 // Called from API entry points which perform stack walking. If the
828 // associated JavaThread is the current thread, then wait_for_suspend
829 // is not used. Otherwise, it determines if we should wait for the
830 // "other" thread to complete external suspension. (NOTE: in future
831 // releases the suspension mechanism should be reimplemented so this
832 // is not necessary.)
833 //
834 bool
835 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
836 if (this != JavaThread::current()) {
837 // "other" threads require special handling.
838 if (wait_for_suspend) {
839 // We are allowed to wait for the external suspend to complete
840 // so give the other thread a chance to get suspended.
841 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
842 SuspendRetryDelay, bits)) {
843 // Didn't make it so let the caller know.
844 return false;
845 }
846 }
847 // We aren't allowed to wait for the external suspend to complete
848 // so if the other thread isn't externally suspended we need to
849 // let the caller know.
850 else if (!is_ext_suspend_completed_with_lock(bits)) {
851 return false;
852 }
853 }
854
855 return true;
856 }
857
858 #ifndef PRODUCT
859 void JavaThread::record_jump(address target, address instr, const char* file,
860 int line) {
861
862 // This should not need to be atomic as the only way for simultaneous
863 // updates is via interrupts. Even then this should be rare or non-existent
864 // and we don't care that much anyway.
865
866 int index = _jmp_ring_index;
867 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
868 _jmp_ring[index]._target = (intptr_t) target;
869 _jmp_ring[index]._instruction = (intptr_t) instr;
870 _jmp_ring[index]._file = file;
871 _jmp_ring[index]._line = line;
872 }
873 #endif // PRODUCT
874
875 void Thread::interrupt(Thread* thread) {
876 debug_only(check_for_dangling_thread_pointer(thread);)
877 os::interrupt(thread);
878 }
879
880 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
881 debug_only(check_for_dangling_thread_pointer(thread);)
882 // Note: If clear_interrupted==false, this simply fetches and
883 // returns the value of the field osthread()->interrupted().
884 return os::is_interrupted(thread, clear_interrupted);
885 }
886
887
888 // GC Support
889 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
890 int thread_parity = _oops_do_parity;
891 if (thread_parity != strong_roots_parity) {
892 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
893 if (res == thread_parity) {
894 return true;
895 } else {
896 guarantee(res == strong_roots_parity, "Or else what?");
897 return false;
898 }
899 }
900 return false;
901 }
902
903 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
904 active_handles()->oops_do(f);
905 // Do oop for ThreadShadow
906 f->do_oop((oop*)&_pending_exception);
907 handle_area()->oops_do(f);
908
909 // We scan thread local monitor lists here, and the remaining global
910 // monitors in ObjectSynchronizer::oops_do().
911 ObjectSynchronizer::thread_local_used_oops_do(this, f);
912 }
913
914 void Thread::metadata_handles_do(void f(Metadata*)) {
915 // Only walk the Handles in Thread.
916 if (metadata_handles() != NULL) {
917 for (int i = 0; i< metadata_handles()->length(); i++) {
918 f(metadata_handles()->at(i));
919 }
920 }
921 }
922
923 void Thread::print_on(outputStream* st, bool print_extended_info) const {
924 // get_priority assumes osthread initialized
925 if (osthread() != NULL) {
926 int os_prio;
927 if (os::get_native_priority(this, &os_prio) == OS_OK) {
928 st->print("os_prio=%d ", os_prio);
929 }
930
931 st->print("cpu=%.2fms ",
932 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
933 );
934 st->print("elapsed=%.2fs ",
935 _statistical_info.getElapsedTime() / 1000.0
936 );
937 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
938 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
939 st->print("allocated=" SIZE_FORMAT "%s ",
940 byte_size_in_proper_unit(allocated_bytes),
941 proper_unit_for_byte_size(allocated_bytes)
942 );
943 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
944 }
945
946 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
947 osthread()->print_on(st);
948 }
949 ThreadsSMRSupport::print_info_on(this, st);
950 st->print(" ");
951 debug_only(if (WizardMode) print_owned_locks_on(st);)
952 }
953
954 // Thread::print_on_error() is called by fatal error handler. Don't use
955 // any lock or allocate memory.
956 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
957 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
958
959 if (is_VM_thread()) { st->print("VMThread"); }
960 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
961 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
962 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
963 else { st->print("Thread"); }
964
965 if (is_Named_thread()) {
966 st->print(" \"%s\"", name());
967 }
968
969 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
970 p2i(stack_end()), p2i(stack_base()));
971
972 if (osthread()) {
973 st->print(" [id=%d]", osthread()->thread_id());
974 }
975
976 ThreadsSMRSupport::print_info_on(this, st);
977 }
978
979 void Thread::print_value_on(outputStream* st) const {
980 if (is_Named_thread()) {
981 st->print(" \"%s\" ", name());
982 }
983 st->print(INTPTR_FORMAT, p2i(this)); // print address
984 }
985
986 #ifdef ASSERT
987 void Thread::print_owned_locks_on(outputStream* st) const {
988 Monitor *cur = _owned_locks;
989 if (cur == NULL) {
990 st->print(" (no locks) ");
991 } else {
992 st->print_cr(" Locks owned:");
993 while (cur) {
994 cur->print_on(st);
995 cur = cur->next();
996 }
997 }
998 }
999
1000 static int ref_use_count = 0;
1001
1002 bool Thread::owns_locks_but_compiled_lock() const {
1003 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1004 if (cur != Compile_lock) return true;
1005 }
1006 return false;
1007 }
1008
1009
1010 #endif
1011
1012 #ifndef PRODUCT
1013
1014 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
1015 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
1016 // no locks which allow_vm_block's are held
1017 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
1018 // Check if current thread is allowed to block at a safepoint
1019 if (!(_allow_safepoint_count == 0)) {
1020 fatal("Possible safepoint reached by thread that does not allow it");
1021 }
1022 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
1023 fatal("LEAF method calling lock?");
1024 }
1025
1026 #ifdef ASSERT
1027 if (potential_vm_operation && is_Java_thread()
1028 && !Universe::is_bootstrapping()) {
1029 // Make sure we do not hold any locks that the VM thread also uses.
1030 // This could potentially lead to deadlocks
1031 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1032 // Threads_lock is special, since the safepoint synchronization will not start before this is
1033 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
1034 // since it is used to transfer control between JavaThreads and the VMThread
1035 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
1036 if ((cur->allow_vm_block() &&
1037 cur != Threads_lock &&
1038 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
1039 cur != VMOperationRequest_lock &&
1040 cur != VMOperationQueue_lock) ||
1041 cur->rank() == Mutex::special) {
1042 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
1043 }
1044 }
1045 }
1046
1047 if (GCALotAtAllSafepoints) {
1048 // We could enter a safepoint here and thus have a gc
1049 InterfaceSupport::check_gc_alot();
1050 }
1051 #endif
1052 }
1053 #endif
1054
1055 bool Thread::is_in_stack(address adr) const {
1056 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1057 address end = os::current_stack_pointer();
1058 // Allow non Java threads to call this without stack_base
1059 if (_stack_base == NULL) return true;
1060 if (stack_base() >= adr && adr >= end) return true;
1061
1062 return false;
1063 }
1064
1065 bool Thread::is_in_usable_stack(address adr) const {
1066 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1067 size_t usable_stack_size = _stack_size - stack_guard_size;
1068
1069 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1070 }
1071
1072
1073 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1074 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1075 // used for compilation in the future. If that change is made, the need for these methods
1076 // should be revisited, and they should be removed if possible.
1077
1078 bool Thread::is_lock_owned(address adr) const {
1079 return on_local_stack(adr);
1080 }
1081
1082 bool Thread::set_as_starting_thread() {
1083 assert(_starting_thread == NULL, "already initialized: "
1084 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
1085 // NOTE: this must be called inside the main thread.
1086 DEBUG_ONLY(_starting_thread = this;)
1087 return os::create_main_thread((JavaThread*)this);
1088 }
1089
1090 static void initialize_class(Symbol* class_name, TRAPS) {
1091 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1092 InstanceKlass::cast(klass)->initialize(CHECK);
1093 }
1094
1095
1096 // Creates the initial ThreadGroup
1097 static Handle create_initial_thread_group(TRAPS) {
1098 Handle system_instance = JavaCalls::construct_new_instance(
1099 SystemDictionary::ThreadGroup_klass(),
1100 vmSymbols::void_method_signature(),
1101 CHECK_NH);
1102 Universe::set_system_thread_group(system_instance());
1103
1104 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1105 Handle main_instance = JavaCalls::construct_new_instance(
1106 SystemDictionary::ThreadGroup_klass(),
1107 vmSymbols::threadgroup_string_void_signature(),
1108 system_instance,
1109 string,
1110 CHECK_NH);
1111 return main_instance;
1112 }
1113
1114 // Creates the initial Thread
1115 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1116 TRAPS) {
1117 InstanceKlass* ik = SystemDictionary::Thread_klass();
1118 assert(ik->is_initialized(), "must be");
1119 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1120
1121 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1122 // constructor calls Thread.current(), which must be set here for the
1123 // initial thread.
1124 java_lang_Thread::set_thread(thread_oop(), thread);
1125 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1126 thread->set_threadObj(thread_oop());
1127
1128 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1129
1130 JavaValue result(T_VOID);
1131 JavaCalls::call_special(&result, thread_oop,
1132 ik,
1133 vmSymbols::object_initializer_name(),
1134 vmSymbols::threadgroup_string_void_signature(),
1135 thread_group,
1136 string,
1137 CHECK_NULL);
1138 return thread_oop();
1139 }
1140
1141 char java_runtime_name[128] = "";
1142 char java_runtime_version[128] = "";
1143
1144 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1145 static const char* get_java_runtime_name(TRAPS) {
1146 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1147 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1148 fieldDescriptor fd;
1149 bool found = k != NULL &&
1150 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1151 vmSymbols::string_signature(), &fd);
1152 if (found) {
1153 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1154 if (name_oop == NULL) {
1155 return NULL;
1156 }
1157 const char* name = java_lang_String::as_utf8_string(name_oop,
1158 java_runtime_name,
1159 sizeof(java_runtime_name));
1160 return name;
1161 } else {
1162 return NULL;
1163 }
1164 }
1165
1166 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1167 static const char* get_java_runtime_version(TRAPS) {
1168 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1169 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1170 fieldDescriptor fd;
1171 bool found = k != NULL &&
1172 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1173 vmSymbols::string_signature(), &fd);
1174 if (found) {
1175 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1176 if (name_oop == NULL) {
1177 return NULL;
1178 }
1179 const char* name = java_lang_String::as_utf8_string(name_oop,
1180 java_runtime_version,
1181 sizeof(java_runtime_version));
1182 return name;
1183 } else {
1184 return NULL;
1185 }
1186 }
1187
1188 // General purpose hook into Java code, run once when the VM is initialized.
1189 // The Java library method itself may be changed independently from the VM.
1190 static void call_postVMInitHook(TRAPS) {
1191 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1192 if (klass != NULL) {
1193 JavaValue result(T_VOID);
1194 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1195 vmSymbols::void_method_signature(),
1196 CHECK);
1197 }
1198 }
1199
1200 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1201 bool daemon, TRAPS) {
1202 assert(thread_group.not_null(), "thread group should be specified");
1203 assert(threadObj() == NULL, "should only create Java thread object once");
1204
1205 InstanceKlass* ik = SystemDictionary::Thread_klass();
1206 assert(ik->is_initialized(), "must be");
1207 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1208
1209 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1210 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1211 // constructor calls Thread.current(), which must be set here.
1212 java_lang_Thread::set_thread(thread_oop(), this);
1213 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1214 set_threadObj(thread_oop());
1215
1216 JavaValue result(T_VOID);
1217 if (thread_name != NULL) {
1218 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1219 // Thread gets assigned specified name and null target
1220 JavaCalls::call_special(&result,
1221 thread_oop,
1222 ik,
1223 vmSymbols::object_initializer_name(),
1224 vmSymbols::threadgroup_string_void_signature(),
1225 thread_group,
1226 name,
1227 THREAD);
1228 } else {
1229 // Thread gets assigned name "Thread-nnn" and null target
1230 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1231 JavaCalls::call_special(&result,
1232 thread_oop,
1233 ik,
1234 vmSymbols::object_initializer_name(),
1235 vmSymbols::threadgroup_runnable_void_signature(),
1236 thread_group,
1237 Handle(),
1238 THREAD);
1239 }
1240
1241
1242 if (daemon) {
1243 java_lang_Thread::set_daemon(thread_oop());
1244 }
1245
1246 if (HAS_PENDING_EXCEPTION) {
1247 return;
1248 }
1249
1250 Klass* group = SystemDictionary::ThreadGroup_klass();
1251 Handle threadObj(THREAD, this->threadObj());
1252
1253 JavaCalls::call_special(&result,
1254 thread_group,
1255 group,
1256 vmSymbols::add_method_name(),
1257 vmSymbols::thread_void_signature(),
1258 threadObj, // Arg 1
1259 THREAD);
1260 }
1261
1262 // List of all NonJavaThreads and safe iteration over that list.
1263
1264 class NonJavaThread::List {
1265 public:
1266 NonJavaThread* volatile _head;
1267 SingleWriterSynchronizer _protect;
1268
1269 List() : _head(NULL), _protect() {}
1270 };
1271
1272 NonJavaThread::List NonJavaThread::_the_list;
1273
1274 NonJavaThread::Iterator::Iterator() :
1275 _protect_enter(_the_list._protect.enter()),
1276 _current(OrderAccess::load_acquire(&_the_list._head))
1277 {}
1278
1279 NonJavaThread::Iterator::~Iterator() {
1280 _the_list._protect.exit(_protect_enter);
1281 }
1282
1283 void NonJavaThread::Iterator::step() {
1284 assert(!end(), "precondition");
1285 _current = OrderAccess::load_acquire(&_current->_next);
1286 }
1287
1288 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) {
1289 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!");
1290 }
1291
1292 NonJavaThread::~NonJavaThread() { }
1293
1294 void NonJavaThread::add_to_the_list() {
1295 MutexLockerEx lock(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1296 _next = _the_list._head;
1297 OrderAccess::release_store(&_the_list._head, this);
1298 }
1299
1300 void NonJavaThread::remove_from_the_list() {
1301 MutexLockerEx lock(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1302 NonJavaThread* volatile* p = &_the_list._head;
1303 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) {
1304 if (t == this) {
1305 *p = this->_next;
1306 // Wait for any in-progress iterators. Concurrent synchronize is
1307 // not allowed, so do it while holding the list lock.
1308 _the_list._protect.synchronize();
1309 break;
1310 }
1311 }
1312 }
1313
1314 void NonJavaThread::pre_run() {
1315 // Initialize BarrierSet-related data before adding to list.
1316 assert(BarrierSet::barrier_set() != NULL, "invariant");
1317 BarrierSet::barrier_set()->on_thread_attach(this);
1318 add_to_the_list();
1319
1320 // This is slightly odd in that NamedThread is a subclass, but
1321 // in fact name() is defined in Thread
1322 assert(this->name() != NULL, "thread name was not set before it was started");
1323 this->set_native_thread_name(this->name());
1324 }
1325
1326 void NonJavaThread::post_run() {
1327 JFR_ONLY(Jfr::on_thread_exit(this);)
1328 // Clean up BarrierSet data before removing from list.
1329 BarrierSet::barrier_set()->on_thread_detach(this);
1330 remove_from_the_list();
1331 // Ensure thread-local-storage is cleared before termination.
1332 Thread::clear_thread_current();
1333 }
1334
1335 // NamedThread -- non-JavaThread subclasses with multiple
1336 // uniquely named instances should derive from this.
1337 NamedThread::NamedThread() :
1338 NonJavaThread(),
1339 _name(NULL),
1340 _processed_thread(NULL),
1341 _gc_id(GCId::undefined())
1342 {}
1343
1344 NamedThread::~NamedThread() {
1345 if (_name != NULL) {
1346 FREE_C_HEAP_ARRAY(char, _name);
1347 _name = NULL;
1348 }
1349 }
1350
1351 void NamedThread::set_name(const char* format, ...) {
1352 guarantee(_name == NULL, "Only get to set name once.");
1353 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1354 guarantee(_name != NULL, "alloc failure");
1355 va_list ap;
1356 va_start(ap, format);
1357 jio_vsnprintf(_name, max_name_len, format, ap);
1358 va_end(ap);
1359 }
1360
1361 void NamedThread::print_on(outputStream* st) const {
1362 st->print("\"%s\" ", name());
1363 Thread::print_on(st);
1364 st->cr();
1365 }
1366
1367
1368 // ======= WatcherThread ========
1369
1370 // The watcher thread exists to simulate timer interrupts. It should
1371 // be replaced by an abstraction over whatever native support for
1372 // timer interrupts exists on the platform.
1373
1374 WatcherThread* WatcherThread::_watcher_thread = NULL;
1375 bool WatcherThread::_startable = false;
1376 volatile bool WatcherThread::_should_terminate = false;
1377
1378 WatcherThread::WatcherThread() : NonJavaThread() {
1379 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1380 if (os::create_thread(this, os::watcher_thread)) {
1381 _watcher_thread = this;
1382
1383 // Set the watcher thread to the highest OS priority which should not be
1384 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1385 // is created. The only normal thread using this priority is the reference
1386 // handler thread, which runs for very short intervals only.
1387 // If the VMThread's priority is not lower than the WatcherThread profiling
1388 // will be inaccurate.
1389 os::set_priority(this, MaxPriority);
1390 if (!DisableStartThread) {
1391 os::start_thread(this);
1392 }
1393 }
1394 }
1395
1396 int WatcherThread::sleep() const {
1397 // The WatcherThread does not participate in the safepoint protocol
1398 // for the PeriodicTask_lock because it is not a JavaThread.
1399 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1400
1401 if (_should_terminate) {
1402 // check for termination before we do any housekeeping or wait
1403 return 0; // we did not sleep.
1404 }
1405
1406 // remaining will be zero if there are no tasks,
1407 // causing the WatcherThread to sleep until a task is
1408 // enrolled
1409 int remaining = PeriodicTask::time_to_wait();
1410 int time_slept = 0;
1411
1412 // we expect this to timeout - we only ever get unparked when
1413 // we should terminate or when a new task has been enrolled
1414 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1415
1416 jlong time_before_loop = os::javaTimeNanos();
1417
1418 while (true) {
1419 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1420 remaining);
1421 jlong now = os::javaTimeNanos();
1422
1423 if (remaining == 0) {
1424 // if we didn't have any tasks we could have waited for a long time
1425 // consider the time_slept zero and reset time_before_loop
1426 time_slept = 0;
1427 time_before_loop = now;
1428 } else {
1429 // need to recalculate since we might have new tasks in _tasks
1430 time_slept = (int) ((now - time_before_loop) / 1000000);
1431 }
1432
1433 // Change to task list or spurious wakeup of some kind
1434 if (timedout || _should_terminate) {
1435 break;
1436 }
1437
1438 remaining = PeriodicTask::time_to_wait();
1439 if (remaining == 0) {
1440 // Last task was just disenrolled so loop around and wait until
1441 // another task gets enrolled
1442 continue;
1443 }
1444
1445 remaining -= time_slept;
1446 if (remaining <= 0) {
1447 break;
1448 }
1449 }
1450
1451 return time_slept;
1452 }
1453
1454 void WatcherThread::run() {
1455 assert(this == watcher_thread(), "just checking");
1456
1457 this->set_active_handles(JNIHandleBlock::allocate_block());
1458 while (true) {
1459 assert(watcher_thread() == Thread::current(), "thread consistency check");
1460 assert(watcher_thread() == this, "thread consistency check");
1461
1462 // Calculate how long it'll be until the next PeriodicTask work
1463 // should be done, and sleep that amount of time.
1464 int time_waited = sleep();
1465
1466 if (VMError::is_error_reported()) {
1467 // A fatal error has happened, the error handler(VMError::report_and_die)
1468 // should abort JVM after creating an error log file. However in some
1469 // rare cases, the error handler itself might deadlock. Here periodically
1470 // check for error reporting timeouts, and if it happens, just proceed to
1471 // abort the VM.
1472
1473 // This code is in WatcherThread because WatcherThread wakes up
1474 // periodically so the fatal error handler doesn't need to do anything;
1475 // also because the WatcherThread is less likely to crash than other
1476 // threads.
1477
1478 for (;;) {
1479 // Note: we use naked sleep in this loop because we want to avoid using
1480 // any kind of VM infrastructure which may be broken at this point.
1481 if (VMError::check_timeout()) {
1482 // We hit error reporting timeout. Error reporting was interrupted and
1483 // will be wrapping things up now (closing files etc). Give it some more
1484 // time, then quit the VM.
1485 os::naked_short_sleep(200);
1486 // Print a message to stderr.
1487 fdStream err(defaultStream::output_fd());
1488 err.print_raw_cr("# [ timer expired, abort... ]");
1489 // skip atexit/vm_exit/vm_abort hooks
1490 os::die();
1491 }
1492
1493 // Wait a second, then recheck for timeout.
1494 os::naked_short_sleep(999);
1495 }
1496 }
1497
1498 if (_should_terminate) {
1499 // check for termination before posting the next tick
1500 break;
1501 }
1502
1503 PeriodicTask::real_time_tick(time_waited);
1504 }
1505
1506 // Signal that it is terminated
1507 {
1508 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1509 _watcher_thread = NULL;
1510 Terminator_lock->notify();
1511 }
1512 }
1513
1514 void WatcherThread::start() {
1515 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1516
1517 if (watcher_thread() == NULL && _startable) {
1518 _should_terminate = false;
1519 // Create the single instance of WatcherThread
1520 new WatcherThread();
1521 }
1522 }
1523
1524 void WatcherThread::make_startable() {
1525 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1526 _startable = true;
1527 }
1528
1529 void WatcherThread::stop() {
1530 {
1531 // Follow normal safepoint aware lock enter protocol since the
1532 // WatcherThread is stopped by another JavaThread.
1533 MutexLocker ml(PeriodicTask_lock);
1534 _should_terminate = true;
1535
1536 WatcherThread* watcher = watcher_thread();
1537 if (watcher != NULL) {
1538 // unpark the WatcherThread so it can see that it should terminate
1539 watcher->unpark();
1540 }
1541 }
1542
1543 MutexLocker mu(Terminator_lock);
1544
1545 while (watcher_thread() != NULL) {
1546 // This wait should make safepoint checks, wait without a timeout,
1547 // and wait as a suspend-equivalent condition.
1548 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1549 Mutex::_as_suspend_equivalent_flag);
1550 }
1551 }
1552
1553 void WatcherThread::unpark() {
1554 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1555 PeriodicTask_lock->notify();
1556 }
1557
1558 void WatcherThread::print_on(outputStream* st) const {
1559 st->print("\"%s\" ", name());
1560 Thread::print_on(st);
1561 st->cr();
1562 }
1563
1564 // ======= JavaThread ========
1565
1566 #if INCLUDE_JVMCI
1567
1568 jlong* JavaThread::_jvmci_old_thread_counters;
1569
1570 bool jvmci_counters_include(JavaThread* thread) {
1571 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1572 }
1573
1574 void JavaThread::collect_counters(typeArrayOop array) {
1575 if (JVMCICounterSize > 0) {
1576 JavaThreadIteratorWithHandle jtiwh;
1577 for (int i = 0; i < array->length(); i++) {
1578 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1579 }
1580 for (; JavaThread *tp = jtiwh.next(); ) {
1581 if (jvmci_counters_include(tp)) {
1582 for (int i = 0; i < array->length(); i++) {
1583 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1584 }
1585 }
1586 }
1587 }
1588 }
1589
1590 #endif // INCLUDE_JVMCI
1591
1592 // A JavaThread is a normal Java thread
1593
1594 void JavaThread::initialize() {
1595 // Initialize fields
1596
1597 set_saved_exception_pc(NULL);
1598 set_threadObj(NULL);
1599 _anchor.clear();
1600 set_entry_point(NULL);
1601 set_jni_functions(jni_functions());
1602 set_callee_target(NULL);
1603 set_vm_result(NULL);
1604 set_vm_result_2(NULL);
1605 set_vframe_array_head(NULL);
1606 set_vframe_array_last(NULL);
1607 set_deferred_locals(NULL);
1608 set_deopt_mark(NULL);
1609 set_deopt_compiled_method(NULL);
1610 clear_must_deopt_id();
1611 set_monitor_chunks(NULL);
1612 set_next(NULL);
1613 _on_thread_list = false;
1614 set_thread_state(_thread_new);
1615 _terminated = _not_terminated;
1616 _array_for_gc = NULL;
1617 _suspend_equivalent = false;
1618 _in_deopt_handler = 0;
1619 _doing_unsafe_access = false;
1620 _stack_guard_state = stack_guard_unused;
1621 #if INCLUDE_JVMCI
1622 _pending_monitorenter = false;
1623 _pending_deoptimization = -1;
1624 _pending_failed_speculation = 0;
1625 _pending_transfer_to_interpreter = false;
1626 _adjusting_comp_level = false;
1627 _in_retryable_allocation = false;
1628 _jvmci._alternate_call_target = NULL;
1629 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1630 if (JVMCICounterSize > 0) {
1631 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1632 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1633 } else {
1634 _jvmci_counters = NULL;
1635 }
1636 #endif // INCLUDE_JVMCI
1637 _reserved_stack_activation = NULL; // stack base not known yet
1638 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1639 _exception_pc = 0;
1640 _exception_handler_pc = 0;
1641 _is_method_handle_return = 0;
1642 _jvmti_thread_state= NULL;
1643 _should_post_on_exceptions_flag = JNI_FALSE;
1644 _interp_only_mode = 0;
1645 _special_runtime_exit_condition = _no_async_condition;
1646 _pending_async_exception = NULL;
1647 _thread_stat = NULL;
1648 _thread_stat = new ThreadStatistics();
1649 _blocked_on_compilation = false;
1650 _jni_active_critical = 0;
1651 _pending_jni_exception_check_fn = NULL;
1652 _do_not_unlock_if_synchronized = false;
1653 _cached_monitor_info = NULL;
1654 _parker = Parker::Allocate(this);
1655
1656 #ifndef PRODUCT
1657 _jmp_ring_index = 0;
1658 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1659 record_jump(NULL, NULL, NULL, 0);
1660 }
1661 #endif // PRODUCT
1662
1663 // Setup safepoint state info for this thread
1664 ThreadSafepointState::create(this);
1665
1666 debug_only(_java_call_counter = 0);
1667
1668 // JVMTI PopFrame support
1669 _popframe_condition = popframe_inactive;
1670 _popframe_preserved_args = NULL;
1671 _popframe_preserved_args_size = 0;
1672 _frames_to_pop_failed_realloc = 0;
1673
1674 if (SafepointMechanism::uses_thread_local_poll()) {
1675 SafepointMechanism::initialize_header(this);
1676 }
1677
1678 _class_to_be_initialized = NULL;
1679
1680 pd_initialize();
1681 }
1682
1683 JavaThread::JavaThread(bool is_attaching_via_jni) :
1684 Thread() {
1685 initialize();
1686 if (is_attaching_via_jni) {
1687 _jni_attach_state = _attaching_via_jni;
1688 } else {
1689 _jni_attach_state = _not_attaching_via_jni;
1690 }
1691 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1692 }
1693
1694 bool JavaThread::reguard_stack(address cur_sp) {
1695 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1696 && _stack_guard_state != stack_guard_reserved_disabled) {
1697 return true; // Stack already guarded or guard pages not needed.
1698 }
1699
1700 if (register_stack_overflow()) {
1701 // For those architectures which have separate register and
1702 // memory stacks, we must check the register stack to see if
1703 // it has overflowed.
1704 return false;
1705 }
1706
1707 // Java code never executes within the yellow zone: the latter is only
1708 // there to provoke an exception during stack banging. If java code
1709 // is executing there, either StackShadowPages should be larger, or
1710 // some exception code in c1, c2 or the interpreter isn't unwinding
1711 // when it should.
1712 guarantee(cur_sp > stack_reserved_zone_base(),
1713 "not enough space to reguard - increase StackShadowPages");
1714 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1715 enable_stack_yellow_reserved_zone();
1716 if (reserved_stack_activation() != stack_base()) {
1717 set_reserved_stack_activation(stack_base());
1718 }
1719 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1720 set_reserved_stack_activation(stack_base());
1721 enable_stack_reserved_zone();
1722 }
1723 return true;
1724 }
1725
1726 bool JavaThread::reguard_stack(void) {
1727 return reguard_stack(os::current_stack_pointer());
1728 }
1729
1730
1731 void JavaThread::block_if_vm_exited() {
1732 if (_terminated == _vm_exited) {
1733 // _vm_exited is set at safepoint, and Threads_lock is never released
1734 // we will block here forever
1735 Threads_lock->lock_without_safepoint_check();
1736 ShouldNotReachHere();
1737 }
1738 }
1739
1740
1741 // Remove this ifdef when C1 is ported to the compiler interface.
1742 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1743 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1744
1745 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1746 Thread() {
1747 initialize();
1748 _jni_attach_state = _not_attaching_via_jni;
1749 set_entry_point(entry_point);
1750 // Create the native thread itself.
1751 // %note runtime_23
1752 os::ThreadType thr_type = os::java_thread;
1753 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1754 os::java_thread;
1755 os::create_thread(this, thr_type, stack_sz);
1756 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1757 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1758 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1759 // the exception consists of creating the exception object & initializing it, initialization
1760 // will leave the VM via a JavaCall and then all locks must be unlocked).
1761 //
1762 // The thread is still suspended when we reach here. Thread must be explicit started
1763 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1764 // by calling Threads:add. The reason why this is not done here, is because the thread
1765 // object must be fully initialized (take a look at JVM_Start)
1766 }
1767
1768 JavaThread::~JavaThread() {
1769
1770 // JSR166 -- return the parker to the free list
1771 Parker::Release(_parker);
1772 _parker = NULL;
1773
1774 // Free any remaining previous UnrollBlock
1775 vframeArray* old_array = vframe_array_last();
1776
1777 if (old_array != NULL) {
1778 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1779 old_array->set_unroll_block(NULL);
1780 delete old_info;
1781 delete old_array;
1782 }
1783
1784 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1785 if (deferred != NULL) {
1786 // This can only happen if thread is destroyed before deoptimization occurs.
1787 assert(deferred->length() != 0, "empty array!");
1788 do {
1789 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1790 deferred->remove_at(0);
1791 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1792 delete dlv;
1793 } while (deferred->length() != 0);
1794 delete deferred;
1795 }
1796
1797 // All Java related clean up happens in exit
1798 ThreadSafepointState::destroy(this);
1799 if (_thread_stat != NULL) delete _thread_stat;
1800
1801 #if INCLUDE_JVMCI
1802 if (JVMCICounterSize > 0) {
1803 if (jvmci_counters_include(this)) {
1804 for (int i = 0; i < JVMCICounterSize; i++) {
1805 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1806 }
1807 }
1808 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1809 }
1810 #endif // INCLUDE_JVMCI
1811 }
1812
1813
1814 // First JavaThread specific code executed by a new Java thread.
1815 void JavaThread::pre_run() {
1816 // empty - see comments in run()
1817 }
1818
1819 // The main routine called by a new Java thread. This isn't overridden
1820 // by subclasses, instead different subclasses define a different "entry_point"
1821 // which defines the actual logic for that kind of thread.
1822 void JavaThread::run() {
1823 // initialize thread-local alloc buffer related fields
1824 this->initialize_tlab();
1825
1826 // Used to test validity of stack trace backs.
1827 // This can't be moved into pre_run() else we invalidate
1828 // the requirement that thread_main_inner is lower on
1829 // the stack. Consequently all the initialization logic
1830 // stays here in run() rather than pre_run().
1831 this->record_base_of_stack_pointer();
1832
1833 this->create_stack_guard_pages();
1834
1835 this->cache_global_variables();
1836
1837 // Thread is now sufficiently initialized to be handled by the safepoint code as being
1838 // in the VM. Change thread state from _thread_new to _thread_in_vm
1839 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1840
1841 assert(JavaThread::current() == this, "sanity check");
1842 assert(!Thread::current()->owns_locks(), "sanity check");
1843
1844 DTRACE_THREAD_PROBE(start, this);
1845
1846 // This operation might block. We call that after all safepoint checks for a new thread has
1847 // been completed.
1848 this->set_active_handles(JNIHandleBlock::allocate_block());
1849
1850 if (JvmtiExport::should_post_thread_life()) {
1851 JvmtiExport::post_thread_start(this);
1852
1853 }
1854
1855 // We call another function to do the rest so we are sure that the stack addresses used
1856 // from there will be lower than the stack base just computed.
1857 thread_main_inner();
1858 }
1859
1860 void JavaThread::thread_main_inner() {
1861 assert(JavaThread::current() == this, "sanity check");
1862 assert(this->threadObj() != NULL, "just checking");
1863
1864 // Execute thread entry point unless this thread has a pending exception
1865 // or has been stopped before starting.
1866 // Note: Due to JVM_StopThread we can have pending exceptions already!
1867 if (!this->has_pending_exception() &&
1868 !java_lang_Thread::is_stillborn(this->threadObj())) {
1869 {
1870 ResourceMark rm(this);
1871 this->set_native_thread_name(this->get_thread_name());
1872 }
1873 HandleMark hm(this);
1874 this->entry_point()(this, this);
1875 }
1876
1877 DTRACE_THREAD_PROBE(stop, this);
1878
1879 // Cleanup is handled in post_run()
1880 }
1881
1882 // Shared teardown for all JavaThreads
1883 void JavaThread::post_run() {
1884 this->exit(false);
1885 // Defer deletion to here to ensure 'this' is still referenceable in call_run
1886 // for any shared tear-down.
1887 this->smr_delete();
1888 }
1889
1890 static void ensure_join(JavaThread* thread) {
1891 // We do not need to grab the Threads_lock, since we are operating on ourself.
1892 Handle threadObj(thread, thread->threadObj());
1893 assert(threadObj.not_null(), "java thread object must exist");
1894 ObjectLocker lock(threadObj, thread);
1895 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1896 thread->clear_pending_exception();
1897 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1898 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1899 // Clear the native thread instance - this makes isAlive return false and allows the join()
1900 // to complete once we've done the notify_all below
1901 java_lang_Thread::set_thread(threadObj(), NULL);
1902 lock.notify_all(thread);
1903 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1904 thread->clear_pending_exception();
1905 }
1906
1907 static bool is_daemon(oop threadObj) {
1908 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
1909 }
1910
1911 // For any new cleanup additions, please check to see if they need to be applied to
1912 // cleanup_failed_attach_current_thread as well.
1913 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1914 assert(this == JavaThread::current(), "thread consistency check");
1915
1916 elapsedTimer _timer_exit_phase1;
1917 elapsedTimer _timer_exit_phase2;
1918 elapsedTimer _timer_exit_phase3;
1919 elapsedTimer _timer_exit_phase4;
1920
1921 if (log_is_enabled(Debug, os, thread, timer)) {
1922 _timer_exit_phase1.start();
1923 }
1924
1925 HandleMark hm(this);
1926 Handle uncaught_exception(this, this->pending_exception());
1927 this->clear_pending_exception();
1928 Handle threadObj(this, this->threadObj());
1929 assert(threadObj.not_null(), "Java thread object should be created");
1930
1931 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1932 {
1933 EXCEPTION_MARK;
1934
1935 CLEAR_PENDING_EXCEPTION;
1936 }
1937 if (!destroy_vm) {
1938 if (uncaught_exception.not_null()) {
1939 EXCEPTION_MARK;
1940 // Call method Thread.dispatchUncaughtException().
1941 Klass* thread_klass = SystemDictionary::Thread_klass();
1942 JavaValue result(T_VOID);
1943 JavaCalls::call_virtual(&result,
1944 threadObj, thread_klass,
1945 vmSymbols::dispatchUncaughtException_name(),
1946 vmSymbols::throwable_void_signature(),
1947 uncaught_exception,
1948 THREAD);
1949 if (HAS_PENDING_EXCEPTION) {
1950 ResourceMark rm(this);
1951 jio_fprintf(defaultStream::error_stream(),
1952 "\nException: %s thrown from the UncaughtExceptionHandler"
1953 " in thread \"%s\"\n",
1954 pending_exception()->klass()->external_name(),
1955 get_thread_name());
1956 CLEAR_PENDING_EXCEPTION;
1957 }
1958 }
1959 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
1960
1961 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1962 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1963 // is deprecated anyhow.
1964 if (!is_Compiler_thread()) {
1965 int count = 3;
1966 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1967 EXCEPTION_MARK;
1968 JavaValue result(T_VOID);
1969 Klass* thread_klass = SystemDictionary::Thread_klass();
1970 JavaCalls::call_virtual(&result,
1971 threadObj, thread_klass,
1972 vmSymbols::exit_method_name(),
1973 vmSymbols::void_method_signature(),
1974 THREAD);
1975 CLEAR_PENDING_EXCEPTION;
1976 }
1977 }
1978 // notify JVMTI
1979 if (JvmtiExport::should_post_thread_life()) {
1980 JvmtiExport::post_thread_end(this);
1981 }
1982
1983 // We have notified the agents that we are exiting, before we go on,
1984 // we must check for a pending external suspend request and honor it
1985 // in order to not surprise the thread that made the suspend request.
1986 while (true) {
1987 {
1988 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1989 if (!is_external_suspend()) {
1990 set_terminated(_thread_exiting);
1991 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
1992 break;
1993 }
1994 // Implied else:
1995 // Things get a little tricky here. We have a pending external
1996 // suspend request, but we are holding the SR_lock so we
1997 // can't just self-suspend. So we temporarily drop the lock
1998 // and then self-suspend.
1999 }
2000
2001 ThreadBlockInVM tbivm(this);
2002 java_suspend_self();
2003
2004 // We're done with this suspend request, but we have to loop around
2005 // and check again. Eventually we will get SR_lock without a pending
2006 // external suspend request and will be able to mark ourselves as
2007 // exiting.
2008 }
2009 // no more external suspends are allowed at this point
2010 } else {
2011 assert(!is_terminated() && !is_exiting(), "must not be exiting");
2012 // before_exit() has already posted JVMTI THREAD_END events
2013 }
2014
2015 if (log_is_enabled(Debug, os, thread, timer)) {
2016 _timer_exit_phase1.stop();
2017 _timer_exit_phase2.start();
2018 }
2019 // Notify waiters on thread object. This has to be done after exit() is called
2020 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
2021 // group should have the destroyed bit set before waiters are notified).
2022 ensure_join(this);
2023 assert(!this->has_pending_exception(), "ensure_join should have cleared");
2024
2025 if (log_is_enabled(Debug, os, thread, timer)) {
2026 _timer_exit_phase2.stop();
2027 _timer_exit_phase3.start();
2028 }
2029 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
2030 // held by this thread must be released. The spec does not distinguish
2031 // between JNI-acquired and regular Java monitors. We can only see
2032 // regular Java monitors here if monitor enter-exit matching is broken.
2033 //
2034 // ensure_join() ignores IllegalThreadStateExceptions, and so does
2035 // ObjectSynchronizer::release_monitors_owned_by_thread().
2036 if (exit_type == jni_detach) {
2037 // Sanity check even though JNI DetachCurrentThread() would have
2038 // returned JNI_ERR if there was a Java frame. JavaThread exit
2039 // should be done executing Java code by the time we get here.
2040 assert(!this->has_last_Java_frame(),
2041 "should not have a Java frame when detaching or exiting");
2042 ObjectSynchronizer::release_monitors_owned_by_thread(this);
2043 assert(!this->has_pending_exception(), "release_monitors should have cleared");
2044 }
2045
2046 // These things needs to be done while we are still a Java Thread. Make sure that thread
2047 // is in a consistent state, in case GC happens
2048 JFR_ONLY(Jfr::on_thread_exit(this);)
2049
2050 if (active_handles() != NULL) {
2051 JNIHandleBlock* block = active_handles();
2052 set_active_handles(NULL);
2053 JNIHandleBlock::release_block(block);
2054 }
2055
2056 if (free_handle_block() != NULL) {
2057 JNIHandleBlock* block = free_handle_block();
2058 set_free_handle_block(NULL);
2059 JNIHandleBlock::release_block(block);
2060 }
2061
2062 // These have to be removed while this is still a valid thread.
2063 remove_stack_guard_pages();
2064
2065 if (UseTLAB) {
2066 tlab().retire();
2067 }
2068
2069 if (JvmtiEnv::environments_might_exist()) {
2070 JvmtiExport::cleanup_thread(this);
2071 }
2072
2073 // We must flush any deferred card marks and other various GC barrier
2074 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2075 // before removing a thread from the list of active threads.
2076 BarrierSet::barrier_set()->on_thread_detach(this);
2077
2078 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2079 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2080 os::current_thread_id());
2081
2082 if (log_is_enabled(Debug, os, thread, timer)) {
2083 _timer_exit_phase3.stop();
2084 _timer_exit_phase4.start();
2085 }
2086 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2087 Threads::remove(this);
2088
2089 if (log_is_enabled(Debug, os, thread, timer)) {
2090 _timer_exit_phase4.stop();
2091 ResourceMark rm(this);
2092 log_debug(os, thread, timer)("name='%s'"
2093 ", exit-phase1=" JLONG_FORMAT
2094 ", exit-phase2=" JLONG_FORMAT
2095 ", exit-phase3=" JLONG_FORMAT
2096 ", exit-phase4=" JLONG_FORMAT,
2097 get_thread_name(),
2098 _timer_exit_phase1.milliseconds(),
2099 _timer_exit_phase2.milliseconds(),
2100 _timer_exit_phase3.milliseconds(),
2101 _timer_exit_phase4.milliseconds());
2102 }
2103 }
2104
2105 void JavaThread::cleanup_failed_attach_current_thread() {
2106 if (active_handles() != NULL) {
2107 JNIHandleBlock* block = active_handles();
2108 set_active_handles(NULL);
2109 JNIHandleBlock::release_block(block);
2110 }
2111
2112 if (free_handle_block() != NULL) {
2113 JNIHandleBlock* block = free_handle_block();
2114 set_free_handle_block(NULL);
2115 JNIHandleBlock::release_block(block);
2116 }
2117
2118 // These have to be removed while this is still a valid thread.
2119 remove_stack_guard_pages();
2120
2121 if (UseTLAB) {
2122 tlab().retire();
2123 }
2124
2125 BarrierSet::barrier_set()->on_thread_detach(this);
2126
2127 Threads::remove(this);
2128 this->smr_delete();
2129 }
2130
2131 JavaThread* JavaThread::active() {
2132 Thread* thread = Thread::current();
2133 if (thread->is_Java_thread()) {
2134 return (JavaThread*) thread;
2135 } else {
2136 assert(thread->is_VM_thread(), "this must be a vm thread");
2137 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2138 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2139 assert(ret->is_Java_thread(), "must be a Java thread");
2140 return ret;
2141 }
2142 }
2143
2144 bool JavaThread::is_lock_owned(address adr) const {
2145 if (Thread::is_lock_owned(adr)) return true;
2146
2147 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2148 if (chunk->contains(adr)) return true;
2149 }
2150
2151 return false;
2152 }
2153
2154
2155 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2156 chunk->set_next(monitor_chunks());
2157 set_monitor_chunks(chunk);
2158 }
2159
2160 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2161 guarantee(monitor_chunks() != NULL, "must be non empty");
2162 if (monitor_chunks() == chunk) {
2163 set_monitor_chunks(chunk->next());
2164 } else {
2165 MonitorChunk* prev = monitor_chunks();
2166 while (prev->next() != chunk) prev = prev->next();
2167 prev->set_next(chunk->next());
2168 }
2169 }
2170
2171 // JVM support.
2172
2173 // Note: this function shouldn't block if it's called in
2174 // _thread_in_native_trans state (such as from
2175 // check_special_condition_for_native_trans()).
2176 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2177
2178 if (has_last_Java_frame() && has_async_condition()) {
2179 // If we are at a polling page safepoint (not a poll return)
2180 // then we must defer async exception because live registers
2181 // will be clobbered by the exception path. Poll return is
2182 // ok because the call we a returning from already collides
2183 // with exception handling registers and so there is no issue.
2184 // (The exception handling path kills call result registers but
2185 // this is ok since the exception kills the result anyway).
2186
2187 if (is_at_poll_safepoint()) {
2188 // if the code we are returning to has deoptimized we must defer
2189 // the exception otherwise live registers get clobbered on the
2190 // exception path before deoptimization is able to retrieve them.
2191 //
2192 RegisterMap map(this, false);
2193 frame caller_fr = last_frame().sender(&map);
2194 assert(caller_fr.is_compiled_frame(), "what?");
2195 if (caller_fr.is_deoptimized_frame()) {
2196 log_info(exceptions)("deferred async exception at compiled safepoint");
2197 return;
2198 }
2199 }
2200 }
2201
2202 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2203 if (condition == _no_async_condition) {
2204 // Conditions have changed since has_special_runtime_exit_condition()
2205 // was called:
2206 // - if we were here only because of an external suspend request,
2207 // then that was taken care of above (or cancelled) so we are done
2208 // - if we were here because of another async request, then it has
2209 // been cleared between the has_special_runtime_exit_condition()
2210 // and now so again we are done
2211 return;
2212 }
2213
2214 // Check for pending async. exception
2215 if (_pending_async_exception != NULL) {
2216 // Only overwrite an already pending exception, if it is not a threadDeath.
2217 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2218
2219 // We cannot call Exceptions::_throw(...) here because we cannot block
2220 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2221
2222 LogTarget(Info, exceptions) lt;
2223 if (lt.is_enabled()) {
2224 ResourceMark rm;
2225 LogStream ls(lt);
2226 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2227 if (has_last_Java_frame()) {
2228 frame f = last_frame();
2229 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2230 }
2231 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2232 }
2233 _pending_async_exception = NULL;
2234 clear_has_async_exception();
2235 }
2236 }
2237
2238 if (check_unsafe_error &&
2239 condition == _async_unsafe_access_error && !has_pending_exception()) {
2240 condition = _no_async_condition; // done
2241 switch (thread_state()) {
2242 case _thread_in_vm: {
2243 JavaThread* THREAD = this;
2244 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2245 }
2246 case _thread_in_native: {
2247 ThreadInVMfromNative tiv(this);
2248 JavaThread* THREAD = this;
2249 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2250 }
2251 case _thread_in_Java: {
2252 ThreadInVMfromJava tiv(this);
2253 JavaThread* THREAD = this;
2254 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2255 }
2256 default:
2257 ShouldNotReachHere();
2258 }
2259 }
2260
2261 assert(condition == _no_async_condition || has_pending_exception() ||
2262 (!check_unsafe_error && condition == _async_unsafe_access_error),
2263 "must have handled the async condition, if no exception");
2264 }
2265
2266 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2267 //
2268 // Check for pending external suspend. Internal suspend requests do
2269 // not use handle_special_runtime_exit_condition().
2270 // If JNIEnv proxies are allowed, don't self-suspend if the target
2271 // thread is not the current thread. In older versions of jdbx, jdbx
2272 // threads could call into the VM with another thread's JNIEnv so we
2273 // can be here operating on behalf of a suspended thread (4432884).
2274 bool do_self_suspend = is_external_suspend_with_lock();
2275 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2276 //
2277 // Because thread is external suspended the safepoint code will count
2278 // thread as at a safepoint. This can be odd because we can be here
2279 // as _thread_in_Java which would normally transition to _thread_blocked
2280 // at a safepoint. We would like to mark the thread as _thread_blocked
2281 // before calling java_suspend_self like all other callers of it but
2282 // we must then observe proper safepoint protocol. (We can't leave
2283 // _thread_blocked with a safepoint in progress). However we can be
2284 // here as _thread_in_native_trans so we can't use a normal transition
2285 // constructor/destructor pair because they assert on that type of
2286 // transition. We could do something like:
2287 //
2288 // JavaThreadState state = thread_state();
2289 // set_thread_state(_thread_in_vm);
2290 // {
2291 // ThreadBlockInVM tbivm(this);
2292 // java_suspend_self()
2293 // }
2294 // set_thread_state(_thread_in_vm_trans);
2295 // if (safepoint) block;
2296 // set_thread_state(state);
2297 //
2298 // but that is pretty messy. Instead we just go with the way the
2299 // code has worked before and note that this is the only path to
2300 // java_suspend_self that doesn't put the thread in _thread_blocked
2301 // mode.
2302
2303 frame_anchor()->make_walkable(this);
2304 java_suspend_self();
2305
2306 // We might be here for reasons in addition to the self-suspend request
2307 // so check for other async requests.
2308 }
2309
2310 if (check_asyncs) {
2311 check_and_handle_async_exceptions();
2312 }
2313
2314 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2315 }
2316
2317 void JavaThread::send_thread_stop(oop java_throwable) {
2318 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2319 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2320 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2321
2322 // Do not throw asynchronous exceptions against the compiler thread
2323 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2324 if (!can_call_java()) return;
2325
2326 {
2327 // Actually throw the Throwable against the target Thread - however
2328 // only if there is no thread death exception installed already.
2329 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2330 // If the topmost frame is a runtime stub, then we are calling into
2331 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2332 // must deoptimize the caller before continuing, as the compiled exception handler table
2333 // may not be valid
2334 if (has_last_Java_frame()) {
2335 frame f = last_frame();
2336 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2337 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2338 RegisterMap reg_map(this, UseBiasedLocking);
2339 frame compiled_frame = f.sender(®_map);
2340 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2341 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2342 }
2343 }
2344 }
2345
2346 // Set async. pending exception in thread.
2347 set_pending_async_exception(java_throwable);
2348
2349 if (log_is_enabled(Info, exceptions)) {
2350 ResourceMark rm;
2351 log_info(exceptions)("Pending Async. exception installed of type: %s",
2352 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2353 }
2354 // for AbortVMOnException flag
2355 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2356 }
2357 }
2358
2359
2360 // Interrupt thread so it will wake up from a potential wait()
2361 Thread::interrupt(this);
2362 }
2363
2364 // External suspension mechanism.
2365 //
2366 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2367 // to any VM_locks and it is at a transition
2368 // Self-suspension will happen on the transition out of the vm.
2369 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2370 //
2371 // Guarantees on return:
2372 // + Target thread will not execute any new bytecode (that's why we need to
2373 // force a safepoint)
2374 // + Target thread will not enter any new monitors
2375 //
2376 void JavaThread::java_suspend() {
2377 ThreadsListHandle tlh;
2378 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2379 return;
2380 }
2381
2382 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2383 if (!is_external_suspend()) {
2384 // a racing resume has cancelled us; bail out now
2385 return;
2386 }
2387
2388 // suspend is done
2389 uint32_t debug_bits = 0;
2390 // Warning: is_ext_suspend_completed() may temporarily drop the
2391 // SR_lock to allow the thread to reach a stable thread state if
2392 // it is currently in a transient thread state.
2393 if (is_ext_suspend_completed(false /* !called_by_wait */,
2394 SuspendRetryDelay, &debug_bits)) {
2395 return;
2396 }
2397 }
2398
2399 if (Thread::current() == this) {
2400 // Safely self-suspend.
2401 // If we don't do this explicitly it will implicitly happen
2402 // before we transition back to Java, and on some other thread-state
2403 // transition paths, but not as we exit a JVM TI SuspendThread call.
2404 // As SuspendThread(current) must not return (until resumed) we must
2405 // self-suspend here.
2406 ThreadBlockInVM tbivm(this);
2407 java_suspend_self();
2408 } else {
2409 VM_ThreadSuspend vm_suspend;
2410 VMThread::execute(&vm_suspend);
2411 }
2412 }
2413
2414 // Part II of external suspension.
2415 // A JavaThread self suspends when it detects a pending external suspend
2416 // request. This is usually on transitions. It is also done in places
2417 // where continuing to the next transition would surprise the caller,
2418 // e.g., monitor entry.
2419 //
2420 // Returns the number of times that the thread self-suspended.
2421 //
2422 // Note: DO NOT call java_suspend_self() when you just want to block current
2423 // thread. java_suspend_self() is the second stage of cooperative
2424 // suspension for external suspend requests and should only be used
2425 // to complete an external suspend request.
2426 //
2427 int JavaThread::java_suspend_self() {
2428 int ret = 0;
2429
2430 // we are in the process of exiting so don't suspend
2431 if (is_exiting()) {
2432 clear_external_suspend();
2433 return ret;
2434 }
2435
2436 assert(_anchor.walkable() ||
2437 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2438 "must have walkable stack");
2439
2440 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2441
2442 assert(!this->is_ext_suspended(),
2443 "a thread trying to self-suspend should not already be suspended");
2444
2445 if (this->is_suspend_equivalent()) {
2446 // If we are self-suspending as a result of the lifting of a
2447 // suspend equivalent condition, then the suspend_equivalent
2448 // flag is not cleared until we set the ext_suspended flag so
2449 // that wait_for_ext_suspend_completion() returns consistent
2450 // results.
2451 this->clear_suspend_equivalent();
2452 }
2453
2454 // A racing resume may have cancelled us before we grabbed SR_lock
2455 // above. Or another external suspend request could be waiting for us
2456 // by the time we return from SR_lock()->wait(). The thread
2457 // that requested the suspension may already be trying to walk our
2458 // stack and if we return now, we can change the stack out from under
2459 // it. This would be a "bad thing (TM)" and cause the stack walker
2460 // to crash. We stay self-suspended until there are no more pending
2461 // external suspend requests.
2462 while (is_external_suspend()) {
2463 ret++;
2464 this->set_ext_suspended();
2465
2466 // _ext_suspended flag is cleared by java_resume()
2467 while (is_ext_suspended()) {
2468 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2469 }
2470 }
2471
2472 return ret;
2473 }
2474
2475 #ifdef ASSERT
2476 // Verify the JavaThread has not yet been published in the Threads::list, and
2477 // hence doesn't need protection from concurrent access at this stage.
2478 void JavaThread::verify_not_published() {
2479 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2480 // since an unpublished JavaThread doesn't participate in the
2481 // Thread-SMR protocol for keeping a ThreadsList alive.
2482 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2483 }
2484 #endif
2485
2486 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2487 // progress or when _suspend_flags is non-zero.
2488 // Current thread needs to self-suspend if there is a suspend request and/or
2489 // block if a safepoint is in progress.
2490 // Async exception ISN'T checked.
2491 // Note only the ThreadInVMfromNative transition can call this function
2492 // directly and when thread state is _thread_in_native_trans
2493 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2494 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2495
2496 JavaThread *curJT = JavaThread::current();
2497 bool do_self_suspend = thread->is_external_suspend();
2498
2499 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2500
2501 // If JNIEnv proxies are allowed, don't self-suspend if the target
2502 // thread is not the current thread. In older versions of jdbx, jdbx
2503 // threads could call into the VM with another thread's JNIEnv so we
2504 // can be here operating on behalf of a suspended thread (4432884).
2505 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2506 JavaThreadState state = thread->thread_state();
2507
2508 // We mark this thread_blocked state as a suspend-equivalent so
2509 // that a caller to is_ext_suspend_completed() won't be confused.
2510 // The suspend-equivalent state is cleared by java_suspend_self().
2511 thread->set_suspend_equivalent();
2512
2513 // If the safepoint code sees the _thread_in_native_trans state, it will
2514 // wait until the thread changes to other thread state. There is no
2515 // guarantee on how soon we can obtain the SR_lock and complete the
2516 // self-suspend request. It would be a bad idea to let safepoint wait for
2517 // too long. Temporarily change the state to _thread_blocked to
2518 // let the VM thread know that this thread is ready for GC. The problem
2519 // of changing thread state is that safepoint could happen just after
2520 // java_suspend_self() returns after being resumed, and VM thread will
2521 // see the _thread_blocked state. We must check for safepoint
2522 // after restoring the state and make sure we won't leave while a safepoint
2523 // is in progress.
2524 thread->set_thread_state(_thread_blocked);
2525 thread->java_suspend_self();
2526 thread->set_thread_state(state);
2527
2528 InterfaceSupport::serialize_thread_state_with_handler(thread);
2529 }
2530
2531 SafepointMechanism::block_if_requested(curJT);
2532
2533 if (thread->is_deopt_suspend()) {
2534 thread->clear_deopt_suspend();
2535 RegisterMap map(thread, false);
2536 frame f = thread->last_frame();
2537 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2538 f = f.sender(&map);
2539 }
2540 if (f.id() == thread->must_deopt_id()) {
2541 thread->clear_must_deopt_id();
2542 f.deoptimize(thread);
2543 } else {
2544 fatal("missed deoptimization!");
2545 }
2546 }
2547
2548 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2549 }
2550
2551 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2552 // progress or when _suspend_flags is non-zero.
2553 // Current thread needs to self-suspend if there is a suspend request and/or
2554 // block if a safepoint is in progress.
2555 // Also check for pending async exception (not including unsafe access error).
2556 // Note only the native==>VM/Java barriers can call this function and when
2557 // thread state is _thread_in_native_trans.
2558 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2559 check_safepoint_and_suspend_for_native_trans(thread);
2560
2561 if (thread->has_async_exception()) {
2562 // We are in _thread_in_native_trans state, don't handle unsafe
2563 // access error since that may block.
2564 thread->check_and_handle_async_exceptions(false);
2565 }
2566 }
2567
2568 // This is a variant of the normal
2569 // check_special_condition_for_native_trans with slightly different
2570 // semantics for use by critical native wrappers. It does all the
2571 // normal checks but also performs the transition back into
2572 // thread_in_Java state. This is required so that critical natives
2573 // can potentially block and perform a GC if they are the last thread
2574 // exiting the GCLocker.
2575 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2576 check_special_condition_for_native_trans(thread);
2577
2578 // Finish the transition
2579 thread->set_thread_state(_thread_in_Java);
2580
2581 if (thread->do_critical_native_unlock()) {
2582 ThreadInVMfromJavaNoAsyncException tiv(thread);
2583 GCLocker::unlock_critical(thread);
2584 thread->clear_critical_native_unlock();
2585 }
2586 }
2587
2588 // We need to guarantee the Threads_lock here, since resumes are not
2589 // allowed during safepoint synchronization
2590 // Can only resume from an external suspension
2591 void JavaThread::java_resume() {
2592 assert_locked_or_safepoint(Threads_lock);
2593
2594 // Sanity check: thread is gone, has started exiting or the thread
2595 // was not externally suspended.
2596 ThreadsListHandle tlh;
2597 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2598 return;
2599 }
2600
2601 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2602
2603 clear_external_suspend();
2604
2605 if (is_ext_suspended()) {
2606 clear_ext_suspended();
2607 SR_lock()->notify_all();
2608 }
2609 }
2610
2611 size_t JavaThread::_stack_red_zone_size = 0;
2612 size_t JavaThread::_stack_yellow_zone_size = 0;
2613 size_t JavaThread::_stack_reserved_zone_size = 0;
2614 size_t JavaThread::_stack_shadow_zone_size = 0;
2615
2616 void JavaThread::create_stack_guard_pages() {
2617 if (!os::uses_stack_guard_pages() ||
2618 _stack_guard_state != stack_guard_unused ||
2619 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2620 log_info(os, thread)("Stack guard page creation for thread "
2621 UINTX_FORMAT " disabled", os::current_thread_id());
2622 return;
2623 }
2624 address low_addr = stack_end();
2625 size_t len = stack_guard_zone_size();
2626
2627 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2628 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2629
2630 int must_commit = os::must_commit_stack_guard_pages();
2631 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2632
2633 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2634 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2635 return;
2636 }
2637
2638 if (os::guard_memory((char *) low_addr, len)) {
2639 _stack_guard_state = stack_guard_enabled;
2640 } else {
2641 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2642 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2643 if (os::uncommit_memory((char *) low_addr, len)) {
2644 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2645 }
2646 return;
2647 }
2648
2649 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2650 PTR_FORMAT "-" PTR_FORMAT ".",
2651 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2652 }
2653
2654 void JavaThread::remove_stack_guard_pages() {
2655 assert(Thread::current() == this, "from different thread");
2656 if (_stack_guard_state == stack_guard_unused) return;
2657 address low_addr = stack_end();
2658 size_t len = stack_guard_zone_size();
2659
2660 if (os::must_commit_stack_guard_pages()) {
2661 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2662 _stack_guard_state = stack_guard_unused;
2663 } else {
2664 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2665 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2666 return;
2667 }
2668 } else {
2669 if (_stack_guard_state == stack_guard_unused) return;
2670 if (os::unguard_memory((char *) low_addr, len)) {
2671 _stack_guard_state = stack_guard_unused;
2672 } else {
2673 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2674 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2675 return;
2676 }
2677 }
2678
2679 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2680 PTR_FORMAT "-" PTR_FORMAT ".",
2681 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2682 }
2683
2684 void JavaThread::enable_stack_reserved_zone() {
2685 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state");
2686
2687 // The base notation is from the stack's point of view, growing downward.
2688 // We need to adjust it to work correctly with guard_memory()
2689 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2690
2691 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2692 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2693
2694 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2695 _stack_guard_state = stack_guard_enabled;
2696 } else {
2697 warning("Attempt to guard stack reserved zone failed.");
2698 }
2699 enable_register_stack_guard();
2700 }
2701
2702 void JavaThread::disable_stack_reserved_zone() {
2703 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state");
2704
2705 // Simply return if called for a thread that does not use guard pages.
2706 if (_stack_guard_state != stack_guard_enabled) return;
2707
2708 // The base notation is from the stack's point of view, growing downward.
2709 // We need to adjust it to work correctly with guard_memory()
2710 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2711
2712 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2713 _stack_guard_state = stack_guard_reserved_disabled;
2714 } else {
2715 warning("Attempt to unguard stack reserved zone failed.");
2716 }
2717 disable_register_stack_guard();
2718 }
2719
2720 void JavaThread::enable_stack_yellow_reserved_zone() {
2721 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2722 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2723
2724 // The base notation is from the stacks point of view, growing downward.
2725 // We need to adjust it to work correctly with guard_memory()
2726 address base = stack_red_zone_base();
2727
2728 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2729 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2730
2731 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2732 _stack_guard_state = stack_guard_enabled;
2733 } else {
2734 warning("Attempt to guard stack yellow zone failed.");
2735 }
2736 enable_register_stack_guard();
2737 }
2738
2739 void JavaThread::disable_stack_yellow_reserved_zone() {
2740 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2741 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2742
2743 // Simply return if called for a thread that does not use guard pages.
2744 if (_stack_guard_state == stack_guard_unused) return;
2745
2746 // The base notation is from the stacks point of view, growing downward.
2747 // We need to adjust it to work correctly with guard_memory()
2748 address base = stack_red_zone_base();
2749
2750 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2751 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2752 } else {
2753 warning("Attempt to unguard stack yellow zone failed.");
2754 }
2755 disable_register_stack_guard();
2756 }
2757
2758 void JavaThread::enable_stack_red_zone() {
2759 // The base notation is from the stacks point of view, growing downward.
2760 // We need to adjust it to work correctly with guard_memory()
2761 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2762 address base = stack_red_zone_base() - stack_red_zone_size();
2763
2764 guarantee(base < stack_base(), "Error calculating stack red zone");
2765 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2766
2767 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2768 warning("Attempt to guard stack red zone failed.");
2769 }
2770 }
2771
2772 void JavaThread::disable_stack_red_zone() {
2773 // The base notation is from the stacks point of view, growing downward.
2774 // We need to adjust it to work correctly with guard_memory()
2775 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2776 address base = stack_red_zone_base() - stack_red_zone_size();
2777 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2778 warning("Attempt to unguard stack red zone failed.");
2779 }
2780 }
2781
2782 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2783 // ignore is there is no stack
2784 if (!has_last_Java_frame()) return;
2785 // traverse the stack frames. Starts from top frame.
2786 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2787 frame* fr = fst.current();
2788 f(fr, fst.register_map());
2789 }
2790 }
2791
2792
2793 #ifndef PRODUCT
2794 // Deoptimization
2795 // Function for testing deoptimization
2796 void JavaThread::deoptimize() {
2797 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2798 StackFrameStream fst(this, UseBiasedLocking);
2799 bool deopt = false; // Dump stack only if a deopt actually happens.
2800 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2801 // Iterate over all frames in the thread and deoptimize
2802 for (; !fst.is_done(); fst.next()) {
2803 if (fst.current()->can_be_deoptimized()) {
2804
2805 if (only_at) {
2806 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2807 // consists of comma or carriage return separated numbers so
2808 // search for the current bci in that string.
2809 address pc = fst.current()->pc();
2810 nmethod* nm = (nmethod*) fst.current()->cb();
2811 ScopeDesc* sd = nm->scope_desc_at(pc);
2812 char buffer[8];
2813 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2814 size_t len = strlen(buffer);
2815 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2816 while (found != NULL) {
2817 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2818 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2819 // Check that the bci found is bracketed by terminators.
2820 break;
2821 }
2822 found = strstr(found + 1, buffer);
2823 }
2824 if (!found) {
2825 continue;
2826 }
2827 }
2828
2829 if (DebugDeoptimization && !deopt) {
2830 deopt = true; // One-time only print before deopt
2831 tty->print_cr("[BEFORE Deoptimization]");
2832 trace_frames();
2833 trace_stack();
2834 }
2835 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2836 }
2837 }
2838
2839 if (DebugDeoptimization && deopt) {
2840 tty->print_cr("[AFTER Deoptimization]");
2841 trace_frames();
2842 }
2843 }
2844
2845
2846 // Make zombies
2847 void JavaThread::make_zombies() {
2848 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2849 if (fst.current()->can_be_deoptimized()) {
2850 // it is a Java nmethod
2851 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2852 nm->make_not_entrant();
2853 }
2854 }
2855 }
2856 #endif // PRODUCT
2857
2858
2859 void JavaThread::deoptimized_wrt_marked_nmethods() {
2860 if (!has_last_Java_frame()) return;
2861 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2862 StackFrameStream fst(this, UseBiasedLocking);
2863 for (; !fst.is_done(); fst.next()) {
2864 if (fst.current()->should_be_deoptimized()) {
2865 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2866 }
2867 }
2868 }
2869
2870
2871 // If the caller is a NamedThread, then remember, in the current scope,
2872 // the given JavaThread in its _processed_thread field.
2873 class RememberProcessedThread: public StackObj {
2874 NamedThread* _cur_thr;
2875 public:
2876 RememberProcessedThread(JavaThread* jthr) {
2877 Thread* thread = Thread::current();
2878 if (thread->is_Named_thread()) {
2879 _cur_thr = (NamedThread *)thread;
2880 _cur_thr->set_processed_thread(jthr);
2881 } else {
2882 _cur_thr = NULL;
2883 }
2884 }
2885
2886 ~RememberProcessedThread() {
2887 if (_cur_thr) {
2888 _cur_thr->set_processed_thread(NULL);
2889 }
2890 }
2891 };
2892
2893 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2894 // Verify that the deferred card marks have been flushed.
2895 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2896
2897 // Traverse the GCHandles
2898 Thread::oops_do(f, cf);
2899
2900 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2901 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2902
2903 if (has_last_Java_frame()) {
2904 // Record JavaThread to GC thread
2905 RememberProcessedThread rpt(this);
2906
2907 // traverse the registered growable array
2908 if (_array_for_gc != NULL) {
2909 for (int index = 0; index < _array_for_gc->length(); index++) {
2910 f->do_oop(_array_for_gc->adr_at(index));
2911 }
2912 }
2913
2914 // Traverse the monitor chunks
2915 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2916 chunk->oops_do(f);
2917 }
2918
2919 // Traverse the execution stack
2920 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2921 fst.current()->oops_do(f, cf, fst.register_map());
2922 }
2923 }
2924
2925 // callee_target is never live across a gc point so NULL it here should
2926 // it still contain a methdOop.
2927
2928 set_callee_target(NULL);
2929
2930 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2931 // If we have deferred set_locals there might be oops waiting to be
2932 // written
2933 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2934 if (list != NULL) {
2935 for (int i = 0; i < list->length(); i++) {
2936 list->at(i)->oops_do(f);
2937 }
2938 }
2939
2940 // Traverse instance variables at the end since the GC may be moving things
2941 // around using this function
2942 f->do_oop((oop*) &_threadObj);
2943 f->do_oop((oop*) &_vm_result);
2944 f->do_oop((oop*) &_exception_oop);
2945 f->do_oop((oop*) &_pending_async_exception);
2946
2947 if (jvmti_thread_state() != NULL) {
2948 jvmti_thread_state()->oops_do(f);
2949 }
2950 }
2951
2952 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2953 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2954 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2955
2956 if (has_last_Java_frame()) {
2957 // Traverse the execution stack
2958 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2959 fst.current()->nmethods_do(cf);
2960 }
2961 }
2962 }
2963
2964 void JavaThread::metadata_do(void f(Metadata*)) {
2965 if (has_last_Java_frame()) {
2966 // Traverse the execution stack to call f() on the methods in the stack
2967 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2968 fst.current()->metadata_do(f);
2969 }
2970 } else if (is_Compiler_thread()) {
2971 // need to walk ciMetadata in current compile tasks to keep alive.
2972 CompilerThread* ct = (CompilerThread*)this;
2973 if (ct->env() != NULL) {
2974 ct->env()->metadata_do(f);
2975 }
2976 CompileTask* task = ct->task();
2977 if (task != NULL) {
2978 task->metadata_do(f);
2979 }
2980 }
2981 }
2982
2983 // Printing
2984 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2985 switch (_thread_state) {
2986 case _thread_uninitialized: return "_thread_uninitialized";
2987 case _thread_new: return "_thread_new";
2988 case _thread_new_trans: return "_thread_new_trans";
2989 case _thread_in_native: return "_thread_in_native";
2990 case _thread_in_native_trans: return "_thread_in_native_trans";
2991 case _thread_in_vm: return "_thread_in_vm";
2992 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2993 case _thread_in_Java: return "_thread_in_Java";
2994 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2995 case _thread_blocked: return "_thread_blocked";
2996 case _thread_blocked_trans: return "_thread_blocked_trans";
2997 default: return "unknown thread state";
2998 }
2999 }
3000
3001 #ifndef PRODUCT
3002 void JavaThread::print_thread_state_on(outputStream *st) const {
3003 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
3004 };
3005 void JavaThread::print_thread_state() const {
3006 print_thread_state_on(tty);
3007 }
3008 #endif // PRODUCT
3009
3010 // Called by Threads::print() for VM_PrintThreads operation
3011 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
3012 st->print_raw("\"");
3013 st->print_raw(get_thread_name());
3014 st->print_raw("\" ");
3015 oop thread_oop = threadObj();
3016 if (thread_oop != NULL) {
3017 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
3018 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
3019 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
3020 }
3021 Thread::print_on(st, print_extended_info);
3022 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
3023 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
3024 if (thread_oop != NULL) {
3025 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3026 }
3027 #ifndef PRODUCT
3028 _safepoint_state->print_on(st);
3029 #endif // PRODUCT
3030 if (is_Compiler_thread()) {
3031 CompileTask *task = ((CompilerThread*)this)->task();
3032 if (task != NULL) {
3033 st->print(" Compiling: ");
3034 task->print(st, NULL, true, false);
3035 } else {
3036 st->print(" No compile task");
3037 }
3038 st->cr();
3039 }
3040 }
3041
3042 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3043 st->print("%s", get_thread_name_string(buf, buflen));
3044 }
3045
3046 // Called by fatal error handler. The difference between this and
3047 // JavaThread::print() is that we can't grab lock or allocate memory.
3048 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3049 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3050 oop thread_obj = threadObj();
3051 if (thread_obj != NULL) {
3052 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3053 }
3054 st->print(" [");
3055 st->print("%s", _get_thread_state_name(_thread_state));
3056 if (osthread()) {
3057 st->print(", id=%d", osthread()->thread_id());
3058 }
3059 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3060 p2i(stack_end()), p2i(stack_base()));
3061 st->print("]");
3062
3063 ThreadsSMRSupport::print_info_on(this, st);
3064 return;
3065 }
3066
3067 // Verification
3068
3069 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3070
3071 void JavaThread::verify() {
3072 // Verify oops in the thread.
3073 oops_do(&VerifyOopClosure::verify_oop, NULL);
3074
3075 // Verify the stack frames.
3076 frames_do(frame_verify);
3077 }
3078
3079 // CR 6300358 (sub-CR 2137150)
3080 // Most callers of this method assume that it can't return NULL but a
3081 // thread may not have a name whilst it is in the process of attaching to
3082 // the VM - see CR 6412693, and there are places where a JavaThread can be
3083 // seen prior to having it's threadObj set (eg JNI attaching threads and
3084 // if vm exit occurs during initialization). These cases can all be accounted
3085 // for such that this method never returns NULL.
3086 const char* JavaThread::get_thread_name() const {
3087 #ifdef ASSERT
3088 // early safepoints can hit while current thread does not yet have TLS
3089 if (!SafepointSynchronize::is_at_safepoint()) {
3090 Thread *cur = Thread::current();
3091 if (!(cur->is_Java_thread() && cur == this)) {
3092 // Current JavaThreads are allowed to get their own name without
3093 // the Threads_lock.
3094 assert_locked_or_safepoint(Threads_lock);
3095 }
3096 }
3097 #endif // ASSERT
3098 return get_thread_name_string();
3099 }
3100
3101 // Returns a non-NULL representation of this thread's name, or a suitable
3102 // descriptive string if there is no set name
3103 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3104 const char* name_str;
3105 oop thread_obj = threadObj();
3106 if (thread_obj != NULL) {
3107 oop name = java_lang_Thread::name(thread_obj);
3108 if (name != NULL) {
3109 if (buf == NULL) {
3110 name_str = java_lang_String::as_utf8_string(name);
3111 } else {
3112 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3113 }
3114 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3115 name_str = "<no-name - thread is attaching>";
3116 } else {
3117 name_str = Thread::name();
3118 }
3119 } else {
3120 name_str = Thread::name();
3121 }
3122 assert(name_str != NULL, "unexpected NULL thread name");
3123 return name_str;
3124 }
3125
3126
3127 const char* JavaThread::get_threadgroup_name() const {
3128 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3129 oop thread_obj = threadObj();
3130 if (thread_obj != NULL) {
3131 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3132 if (thread_group != NULL) {
3133 // ThreadGroup.name can be null
3134 return java_lang_ThreadGroup::name(thread_group);
3135 }
3136 }
3137 return NULL;
3138 }
3139
3140 const char* JavaThread::get_parent_name() const {
3141 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3142 oop thread_obj = threadObj();
3143 if (thread_obj != NULL) {
3144 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3145 if (thread_group != NULL) {
3146 oop parent = java_lang_ThreadGroup::parent(thread_group);
3147 if (parent != NULL) {
3148 // ThreadGroup.name can be null
3149 return java_lang_ThreadGroup::name(parent);
3150 }
3151 }
3152 }
3153 return NULL;
3154 }
3155
3156 ThreadPriority JavaThread::java_priority() const {
3157 oop thr_oop = threadObj();
3158 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3159 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3160 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3161 return priority;
3162 }
3163
3164 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3165
3166 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3167 // Link Java Thread object <-> C++ Thread
3168
3169 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3170 // and put it into a new Handle. The Handle "thread_oop" can then
3171 // be used to pass the C++ thread object to other methods.
3172
3173 // Set the Java level thread object (jthread) field of the
3174 // new thread (a JavaThread *) to C++ thread object using the
3175 // "thread_oop" handle.
3176
3177 // Set the thread field (a JavaThread *) of the
3178 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3179
3180 Handle thread_oop(Thread::current(),
3181 JNIHandles::resolve_non_null(jni_thread));
3182 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3183 "must be initialized");
3184 set_threadObj(thread_oop());
3185 java_lang_Thread::set_thread(thread_oop(), this);
3186
3187 if (prio == NoPriority) {
3188 prio = java_lang_Thread::priority(thread_oop());
3189 assert(prio != NoPriority, "A valid priority should be present");
3190 }
3191
3192 // Push the Java priority down to the native thread; needs Threads_lock
3193 Thread::set_priority(this, prio);
3194
3195 // Add the new thread to the Threads list and set it in motion.
3196 // We must have threads lock in order to call Threads::add.
3197 // It is crucial that we do not block before the thread is
3198 // added to the Threads list for if a GC happens, then the java_thread oop
3199 // will not be visited by GC.
3200 Threads::add(this);
3201 }
3202
3203 oop JavaThread::current_park_blocker() {
3204 // Support for JSR-166 locks
3205 oop thread_oop = threadObj();
3206 if (thread_oop != NULL &&
3207 JDK_Version::current().supports_thread_park_blocker()) {
3208 return java_lang_Thread::park_blocker(thread_oop);
3209 }
3210 return NULL;
3211 }
3212
3213
3214 void JavaThread::print_stack_on(outputStream* st) {
3215 if (!has_last_Java_frame()) return;
3216 ResourceMark rm;
3217 HandleMark hm;
3218
3219 RegisterMap reg_map(this);
3220 vframe* start_vf = last_java_vframe(®_map);
3221 int count = 0;
3222 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3223 if (f->is_java_frame()) {
3224 javaVFrame* jvf = javaVFrame::cast(f);
3225 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3226
3227 // Print out lock information
3228 if (JavaMonitorsInStackTrace) {
3229 jvf->print_lock_info_on(st, count);
3230 }
3231 } else {
3232 // Ignore non-Java frames
3233 }
3234
3235 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3236 count++;
3237 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3238 }
3239 }
3240
3241
3242 // JVMTI PopFrame support
3243 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3244 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3245 if (in_bytes(size_in_bytes) != 0) {
3246 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3247 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3248 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3249 }
3250 }
3251
3252 void* JavaThread::popframe_preserved_args() {
3253 return _popframe_preserved_args;
3254 }
3255
3256 ByteSize JavaThread::popframe_preserved_args_size() {
3257 return in_ByteSize(_popframe_preserved_args_size);
3258 }
3259
3260 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3261 int sz = in_bytes(popframe_preserved_args_size());
3262 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3263 return in_WordSize(sz / wordSize);
3264 }
3265
3266 void JavaThread::popframe_free_preserved_args() {
3267 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3268 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3269 _popframe_preserved_args = NULL;
3270 _popframe_preserved_args_size = 0;
3271 }
3272
3273 #ifndef PRODUCT
3274
3275 void JavaThread::trace_frames() {
3276 tty->print_cr("[Describe stack]");
3277 int frame_no = 1;
3278 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3279 tty->print(" %d. ", frame_no++);
3280 fst.current()->print_value_on(tty, this);
3281 tty->cr();
3282 }
3283 }
3284
3285 class PrintAndVerifyOopClosure: public OopClosure {
3286 protected:
3287 template <class T> inline void do_oop_work(T* p) {
3288 oop obj = RawAccess<>::oop_load(p);
3289 if (obj == NULL) return;
3290 tty->print(INTPTR_FORMAT ": ", p2i(p));
3291 if (oopDesc::is_oop_or_null(obj)) {
3292 if (obj->is_objArray()) {
3293 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3294 } else {
3295 obj->print();
3296 }
3297 } else {
3298 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3299 }
3300 tty->cr();
3301 }
3302 public:
3303 virtual void do_oop(oop* p) { do_oop_work(p); }
3304 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3305 };
3306
3307
3308 static void oops_print(frame* f, const RegisterMap *map) {
3309 PrintAndVerifyOopClosure print;
3310 f->print_value();
3311 f->oops_do(&print, NULL, (RegisterMap*)map);
3312 }
3313
3314 // Print our all the locations that contain oops and whether they are
3315 // valid or not. This useful when trying to find the oldest frame
3316 // where an oop has gone bad since the frame walk is from youngest to
3317 // oldest.
3318 void JavaThread::trace_oops() {
3319 tty->print_cr("[Trace oops]");
3320 frames_do(oops_print);
3321 }
3322
3323
3324 #ifdef ASSERT
3325 // Print or validate the layout of stack frames
3326 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3327 ResourceMark rm;
3328 PRESERVE_EXCEPTION_MARK;
3329 FrameValues values;
3330 int frame_no = 0;
3331 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3332 fst.current()->describe(values, ++frame_no);
3333 if (depth == frame_no) break;
3334 }
3335 if (validate_only) {
3336 values.validate();
3337 } else {
3338 tty->print_cr("[Describe stack layout]");
3339 values.print(this);
3340 }
3341 }
3342 #endif
3343
3344 void JavaThread::trace_stack_from(vframe* start_vf) {
3345 ResourceMark rm;
3346 int vframe_no = 1;
3347 for (vframe* f = start_vf; f; f = f->sender()) {
3348 if (f->is_java_frame()) {
3349 javaVFrame::cast(f)->print_activation(vframe_no++);
3350 } else {
3351 f->print();
3352 }
3353 if (vframe_no > StackPrintLimit) {
3354 tty->print_cr("...<more frames>...");
3355 return;
3356 }
3357 }
3358 }
3359
3360
3361 void JavaThread::trace_stack() {
3362 if (!has_last_Java_frame()) return;
3363 ResourceMark rm;
3364 HandleMark hm;
3365 RegisterMap reg_map(this);
3366 trace_stack_from(last_java_vframe(®_map));
3367 }
3368
3369
3370 #endif // PRODUCT
3371
3372
3373 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3374 assert(reg_map != NULL, "a map must be given");
3375 frame f = last_frame();
3376 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3377 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3378 }
3379 return NULL;
3380 }
3381
3382
3383 Klass* JavaThread::security_get_caller_class(int depth) {
3384 vframeStream vfst(this);
3385 vfst.security_get_caller_frame(depth);
3386 if (!vfst.at_end()) {
3387 return vfst.method()->method_holder();
3388 }
3389 return NULL;
3390 }
3391
3392 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3393 assert(thread->is_Compiler_thread(), "must be compiler thread");
3394 CompileBroker::compiler_thread_loop();
3395 }
3396
3397 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3398 NMethodSweeper::sweeper_loop();
3399 }
3400
3401 // Create a CompilerThread
3402 CompilerThread::CompilerThread(CompileQueue* queue,
3403 CompilerCounters* counters)
3404 : JavaThread(&compiler_thread_entry) {
3405 _env = NULL;
3406 _log = NULL;
3407 _task = NULL;
3408 _queue = queue;
3409 _counters = counters;
3410 _buffer_blob = NULL;
3411 _compiler = NULL;
3412
3413 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3414 resource_area()->bias_to(mtCompiler);
3415
3416 #ifndef PRODUCT
3417 _ideal_graph_printer = NULL;
3418 #endif
3419 }
3420
3421 CompilerThread::~CompilerThread() {
3422 // Delete objects which were allocated on heap.
3423 delete _counters;
3424 }
3425
3426 bool CompilerThread::can_call_java() const {
3427 return _compiler != NULL && _compiler->is_jvmci();
3428 }
3429
3430 // Create sweeper thread
3431 CodeCacheSweeperThread::CodeCacheSweeperThread()
3432 : JavaThread(&sweeper_thread_entry) {
3433 _scanned_compiled_method = NULL;
3434 }
3435
3436 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3437 JavaThread::oops_do(f, cf);
3438 if (_scanned_compiled_method != NULL && cf != NULL) {
3439 // Safepoints can occur when the sweeper is scanning an nmethod so
3440 // process it here to make sure it isn't unloaded in the middle of
3441 // a scan.
3442 cf->do_code_blob(_scanned_compiled_method);
3443 }
3444 }
3445
3446 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3447 JavaThread::nmethods_do(cf);
3448 if (_scanned_compiled_method != NULL && cf != NULL) {
3449 // Safepoints can occur when the sweeper is scanning an nmethod so
3450 // process it here to make sure it isn't unloaded in the middle of
3451 // a scan.
3452 cf->do_code_blob(_scanned_compiled_method);
3453 }
3454 }
3455
3456
3457 // ======= Threads ========
3458
3459 // The Threads class links together all active threads, and provides
3460 // operations over all threads. It is protected by the Threads_lock,
3461 // which is also used in other global contexts like safepointing.
3462 // ThreadsListHandles are used to safely perform operations on one
3463 // or more threads without the risk of the thread exiting during the
3464 // operation.
3465 //
3466 // Note: The Threads_lock is currently more widely used than we
3467 // would like. We are actively migrating Threads_lock uses to other
3468 // mechanisms in order to reduce Threads_lock contention.
3469
3470 JavaThread* Threads::_thread_list = NULL;
3471 int Threads::_number_of_threads = 0;
3472 int Threads::_number_of_non_daemon_threads = 0;
3473 int Threads::_return_code = 0;
3474 int Threads::_thread_claim_parity = 0;
3475 size_t JavaThread::_stack_size_at_create = 0;
3476
3477 #ifdef ASSERT
3478 bool Threads::_vm_complete = false;
3479 #endif
3480
3481 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3482 Prefetch::read((void*)addr, prefetch_interval);
3483 return *addr;
3484 }
3485
3486 // Possibly the ugliest for loop the world has seen. C++ does not allow
3487 // multiple types in the declaration section of the for loop. In this case
3488 // we are only dealing with pointers and hence can cast them. It looks ugly
3489 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3490 #define DO_JAVA_THREADS(LIST, X) \
3491 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3492 *MACRO_list = (JavaThread*)(LIST), \
3493 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3494 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3495 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3496 MACRO_current_p != MACRO_end; \
3497 MACRO_current_p++, \
3498 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3499
3500 // All JavaThreads
3501 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3502
3503 // All NonJavaThreads (i.e., every non-JavaThread in the system).
3504 void Threads::non_java_threads_do(ThreadClosure* tc) {
3505 NoSafepointVerifier nsv(!SafepointSynchronize::is_at_safepoint(), false);
3506 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
3507 tc->do_thread(njti.current());
3508 }
3509 }
3510
3511 // All JavaThreads
3512 void Threads::java_threads_do(ThreadClosure* tc) {
3513 assert_locked_or_safepoint(Threads_lock);
3514 // ALL_JAVA_THREADS iterates through all JavaThreads.
3515 ALL_JAVA_THREADS(p) {
3516 tc->do_thread(p);
3517 }
3518 }
3519
3520 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3521 assert_locked_or_safepoint(Threads_lock);
3522 java_threads_do(tc);
3523 tc->do_thread(VMThread::vm_thread());
3524 }
3525
3526 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3527 void Threads::threads_do(ThreadClosure* tc) {
3528 assert_locked_or_safepoint(Threads_lock);
3529 java_threads_do(tc);
3530 non_java_threads_do(tc);
3531 }
3532
3533 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3534 int cp = Threads::thread_claim_parity();
3535 ALL_JAVA_THREADS(p) {
3536 if (p->claim_oops_do(is_par, cp)) {
3537 tc->do_thread(p);
3538 }
3539 }
3540 VMThread* vmt = VMThread::vm_thread();
3541 if (vmt->claim_oops_do(is_par, cp)) {
3542 tc->do_thread(vmt);
3543 }
3544 }
3545
3546 // The system initialization in the library has three phases.
3547 //
3548 // Phase 1: java.lang.System class initialization
3549 // java.lang.System is a primordial class loaded and initialized
3550 // by the VM early during startup. java.lang.System.<clinit>
3551 // only does registerNatives and keeps the rest of the class
3552 // initialization work later until thread initialization completes.
3553 //
3554 // System.initPhase1 initializes the system properties, the static
3555 // fields in, out, and err. Set up java signal handlers, OS-specific
3556 // system settings, and thread group of the main thread.
3557 static void call_initPhase1(TRAPS) {
3558 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3559 JavaValue result(T_VOID);
3560 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3561 vmSymbols::void_method_signature(), CHECK);
3562 }
3563
3564 // Phase 2. Module system initialization
3565 // This will initialize the module system. Only java.base classes
3566 // can be loaded until phase 2 completes.
3567 //
3568 // Call System.initPhase2 after the compiler initialization and jsr292
3569 // classes get initialized because module initialization runs a lot of java
3570 // code, that for performance reasons, should be compiled. Also, this will
3571 // enable the startup code to use lambda and other language features in this
3572 // phase and onward.
3573 //
3574 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3575 static void call_initPhase2(TRAPS) {
3576 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3577
3578 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3579
3580 JavaValue result(T_INT);
3581 JavaCallArguments args;
3582 args.push_int(DisplayVMOutputToStderr);
3583 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3584 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3585 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3586 if (result.get_jint() != JNI_OK) {
3587 vm_exit_during_initialization(); // no message or exception
3588 }
3589
3590 universe_post_module_init();
3591 }
3592
3593 // Phase 3. final setup - set security manager, system class loader and TCCL
3594 //
3595 // This will instantiate and set the security manager, set the system class
3596 // loader as well as the thread context class loader. The security manager
3597 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3598 // other modules or the application's classpath.
3599 static void call_initPhase3(TRAPS) {
3600 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3601 JavaValue result(T_VOID);
3602 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3603 vmSymbols::void_method_signature(), CHECK);
3604 }
3605
3606 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3607 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3608
3609 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3610 create_vm_init_libraries();
3611 }
3612
3613 initialize_class(vmSymbols::java_lang_String(), CHECK);
3614
3615 // Inject CompactStrings value after the static initializers for String ran.
3616 java_lang_String::set_compact_strings(CompactStrings);
3617
3618 // Initialize java_lang.System (needed before creating the thread)
3619 initialize_class(vmSymbols::java_lang_System(), CHECK);
3620 // The VM creates & returns objects of this class. Make sure it's initialized.
3621 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3622 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3623 Handle thread_group = create_initial_thread_group(CHECK);
3624 Universe::set_main_thread_group(thread_group());
3625 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3626 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3627 main_thread->set_threadObj(thread_object);
3628 // Set thread status to running since main thread has
3629 // been started and running.
3630 java_lang_Thread::set_thread_status(thread_object,
3631 java_lang_Thread::RUNNABLE);
3632
3633 // The VM creates objects of this class.
3634 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3635
3636 // The VM preresolves methods to these classes. Make sure that they get initialized
3637 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3638 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3639
3640 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3641 call_initPhase1(CHECK);
3642
3643 // get the Java runtime name after java.lang.System is initialized
3644 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3645 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3646
3647 // an instance of OutOfMemory exception has been allocated earlier
3648 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3649 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3650 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3651 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3652 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3653 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3654 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3655 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3656 }
3657
3658 void Threads::initialize_jsr292_core_classes(TRAPS) {
3659 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3660
3661 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3662 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3663 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3664 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3665 }
3666
3667 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3668 extern void JDK_Version_init();
3669
3670 // Preinitialize version info.
3671 VM_Version::early_initialize();
3672
3673 // Check version
3674 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3675
3676 // Initialize library-based TLS
3677 ThreadLocalStorage::init();
3678
3679 // Initialize the output stream module
3680 ostream_init();
3681
3682 // Process java launcher properties.
3683 Arguments::process_sun_java_launcher_properties(args);
3684
3685 // Initialize the os module
3686 os::init();
3687
3688 // Record VM creation timing statistics
3689 TraceVmCreationTime create_vm_timer;
3690 create_vm_timer.start();
3691
3692 // Initialize system properties.
3693 Arguments::init_system_properties();
3694
3695 // So that JDK version can be used as a discriminator when parsing arguments
3696 JDK_Version_init();
3697
3698 // Update/Initialize System properties after JDK version number is known
3699 Arguments::init_version_specific_system_properties();
3700
3701 // Make sure to initialize log configuration *before* parsing arguments
3702 LogConfiguration::initialize(create_vm_timer.begin_time());
3703
3704 // Parse arguments
3705 // Note: this internally calls os::init_container_support()
3706 jint parse_result = Arguments::parse(args);
3707 if (parse_result != JNI_OK) return parse_result;
3708
3709 os::init_before_ergo();
3710
3711 jint ergo_result = Arguments::apply_ergo();
3712 if (ergo_result != JNI_OK) return ergo_result;
3713
3714 // Final check of all ranges after ergonomics which may change values.
3715 if (!JVMFlagRangeList::check_ranges()) {
3716 return JNI_EINVAL;
3717 }
3718
3719 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3720 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo);
3721 if (!constraint_result) {
3722 return JNI_EINVAL;
3723 }
3724
3725 JVMFlagWriteableList::mark_startup();
3726
3727 if (PauseAtStartup) {
3728 os::pause();
3729 }
3730
3731 HOTSPOT_VM_INIT_BEGIN();
3732
3733 // Timing (must come after argument parsing)
3734 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3735
3736 // Initialize the os module after parsing the args
3737 jint os_init_2_result = os::init_2();
3738 if (os_init_2_result != JNI_OK) return os_init_2_result;
3739
3740 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3741 // Initialize assert poison page mechanism.
3742 if (ShowRegistersOnAssert) {
3743 initialize_assert_poison();
3744 }
3745 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3746
3747 SafepointMechanism::initialize();
3748
3749 jint adjust_after_os_result = Arguments::adjust_after_os();
3750 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3751
3752 // Initialize output stream logging
3753 ostream_init_log();
3754
3755 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3756 // Must be before create_vm_init_agents()
3757 if (Arguments::init_libraries_at_startup()) {
3758 convert_vm_init_libraries_to_agents();
3759 }
3760
3761 // Launch -agentlib/-agentpath and converted -Xrun agents
3762 if (Arguments::init_agents_at_startup()) {
3763 create_vm_init_agents();
3764 }
3765
3766 // Initialize Threads state
3767 _thread_list = NULL;
3768 _number_of_threads = 0;
3769 _number_of_non_daemon_threads = 0;
3770
3771 // Initialize global data structures and create system classes in heap
3772 vm_init_globals();
3773
3774 #if INCLUDE_JVMCI
3775 if (JVMCICounterSize > 0) {
3776 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3777 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3778 } else {
3779 JavaThread::_jvmci_old_thread_counters = NULL;
3780 }
3781 #endif // INCLUDE_JVMCI
3782
3783 // Attach the main thread to this os thread
3784 JavaThread* main_thread = new JavaThread();
3785 main_thread->set_thread_state(_thread_in_vm);
3786 main_thread->initialize_thread_current();
3787 // must do this before set_active_handles
3788 main_thread->record_stack_base_and_size();
3789 main_thread->register_thread_stack_with_NMT();
3790 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3791
3792 if (!main_thread->set_as_starting_thread()) {
3793 vm_shutdown_during_initialization(
3794 "Failed necessary internal allocation. Out of swap space");
3795 main_thread->smr_delete();
3796 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3797 return JNI_ENOMEM;
3798 }
3799
3800 // Enable guard page *after* os::create_main_thread(), otherwise it would
3801 // crash Linux VM, see notes in os_linux.cpp.
3802 main_thread->create_stack_guard_pages();
3803
3804 // Initialize Java-Level synchronization subsystem
3805 ObjectMonitor::Initialize();
3806
3807 // Initialize global modules
3808 jint status = init_globals();
3809 if (status != JNI_OK) {
3810 main_thread->smr_delete();
3811 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3812 return status;
3813 }
3814
3815 JFR_ONLY(Jfr::on_vm_init();)
3816
3817 // Should be done after the heap is fully created
3818 main_thread->cache_global_variables();
3819
3820 HandleMark hm;
3821
3822 { MutexLocker mu(Threads_lock);
3823 Threads::add(main_thread);
3824 }
3825
3826 // Any JVMTI raw monitors entered in onload will transition into
3827 // real raw monitor. VM is setup enough here for raw monitor enter.
3828 JvmtiExport::transition_pending_onload_raw_monitors();
3829
3830 // Create the VMThread
3831 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3832
3833 VMThread::create();
3834 Thread* vmthread = VMThread::vm_thread();
3835
3836 if (!os::create_thread(vmthread, os::vm_thread)) {
3837 vm_exit_during_initialization("Cannot create VM thread. "
3838 "Out of system resources.");
3839 }
3840
3841 // Wait for the VM thread to become ready, and VMThread::run to initialize
3842 // Monitors can have spurious returns, must always check another state flag
3843 {
3844 MutexLocker ml(Notify_lock);
3845 os::start_thread(vmthread);
3846 while (vmthread->active_handles() == NULL) {
3847 Notify_lock->wait();
3848 }
3849 }
3850 }
3851
3852 assert(Universe::is_fully_initialized(), "not initialized");
3853 if (VerifyDuringStartup) {
3854 // Make sure we're starting with a clean slate.
3855 VM_Verify verify_op;
3856 VMThread::execute(&verify_op);
3857 }
3858
3859 // We need this to update the java.vm.info property in case any flags used
3860 // to initially define it have been changed. This is needed for both CDS and
3861 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info
3862 // is initially computed. See Abstract_VM_Version::vm_info_string().
3863 // This update must happen before we initialize the java classes, but
3864 // after any initialization logic that might modify the flags.
3865 Arguments::update_vm_info_property(VM_Version::vm_info_string());
3866
3867 Thread* THREAD = Thread::current();
3868
3869 // Always call even when there are not JVMTI environments yet, since environments
3870 // may be attached late and JVMTI must track phases of VM execution
3871 JvmtiExport::enter_early_start_phase();
3872
3873 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3874 JvmtiExport::post_early_vm_start();
3875
3876 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3877
3878 quicken_jni_functions();
3879
3880 // No more stub generation allowed after that point.
3881 StubCodeDesc::freeze();
3882
3883 // Set flag that basic initialization has completed. Used by exceptions and various
3884 // debug stuff, that does not work until all basic classes have been initialized.
3885 set_init_completed();
3886
3887 LogConfiguration::post_initialize();
3888 Metaspace::post_initialize();
3889
3890 HOTSPOT_VM_INIT_END();
3891
3892 // record VM initialization completion time
3893 #if INCLUDE_MANAGEMENT
3894 Management::record_vm_init_completed();
3895 #endif // INCLUDE_MANAGEMENT
3896
3897 // Signal Dispatcher needs to be started before VMInit event is posted
3898 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3899
3900 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3901 if (!DisableAttachMechanism) {
3902 AttachListener::vm_start();
3903 if (StartAttachListener || AttachListener::init_at_startup()) {
3904 AttachListener::init();
3905 }
3906 }
3907
3908 // Launch -Xrun agents
3909 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3910 // back-end can launch with -Xdebug -Xrunjdwp.
3911 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3912 create_vm_init_libraries();
3913 }
3914
3915 if (CleanChunkPoolAsync) {
3916 Chunk::start_chunk_pool_cleaner_task();
3917 }
3918
3919 // initialize compiler(s)
3920 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3921 #if INCLUDE_JVMCI
3922 bool force_JVMCI_intialization = false;
3923 if (EnableJVMCI) {
3924 // Initialize JVMCI eagerly when it is explicitly requested.
3925 // Or when JVMCIPrintProperties is enabled.
3926 // The JVMCI Java initialization code will read this flag and
3927 // do the printing if it's set.
3928 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties;
3929
3930 if (!force_JVMCI_intialization) {
3931 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3932 // compilations via JVMCI will not actually block until JVMCI is initialized.
3933 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3934 }
3935 }
3936 #endif
3937 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
3938 // Postpone completion of compiler initialization to after JVMCI
3939 // is initialized to avoid timeouts of blocking compilations.
3940 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
3941 CompileBroker::compilation_init_phase2();
3942 }
3943 #endif
3944
3945 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3946 // It is done after compilers are initialized, because otherwise compilations of
3947 // signature polymorphic MH intrinsics can be missed
3948 // (see SystemDictionary::find_method_handle_intrinsic).
3949 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3950
3951 // This will initialize the module system. Only java.base classes can be
3952 // loaded until phase 2 completes
3953 call_initPhase2(CHECK_JNI_ERR);
3954
3955 // Always call even when there are not JVMTI environments yet, since environments
3956 // may be attached late and JVMTI must track phases of VM execution
3957 JvmtiExport::enter_start_phase();
3958
3959 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3960 JvmtiExport::post_vm_start();
3961
3962 // Final system initialization including security manager and system class loader
3963 call_initPhase3(CHECK_JNI_ERR);
3964
3965 // cache the system and platform class loaders
3966 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
3967
3968 #if INCLUDE_CDS
3969 if (DumpSharedSpaces) {
3970 // capture the module path info from the ModuleEntryTable
3971 ClassLoader::initialize_module_path(THREAD);
3972 }
3973 #endif
3974
3975 #if INCLUDE_JVMCI
3976 if (force_JVMCI_intialization) {
3977 JVMCIRuntime::force_initialization(CHECK_JNI_ERR);
3978 CompileBroker::compilation_init_phase2();
3979 }
3980 #endif
3981
3982 // Always call even when there are not JVMTI environments yet, since environments
3983 // may be attached late and JVMTI must track phases of VM execution
3984 JvmtiExport::enter_live_phase();
3985
3986 // Make perfmemory accessible
3987 PerfMemory::set_accessible(true);
3988
3989 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3990 JvmtiExport::post_vm_initialized();
3991
3992 JFR_ONLY(Jfr::on_vm_start();)
3993
3994 #if INCLUDE_MANAGEMENT
3995 Management::initialize(THREAD);
3996
3997 if (HAS_PENDING_EXCEPTION) {
3998 // management agent fails to start possibly due to
3999 // configuration problem and is responsible for printing
4000 // stack trace if appropriate. Simply exit VM.
4001 vm_exit(1);
4002 }
4003 #endif // INCLUDE_MANAGEMENT
4004
4005 if (MemProfiling) MemProfiler::engage();
4006 StatSampler::engage();
4007 if (CheckJNICalls) JniPeriodicChecker::engage();
4008
4009 BiasedLocking::init();
4010
4011 #if INCLUDE_RTM_OPT
4012 RTMLockingCounters::init();
4013 #endif
4014
4015 if (JDK_Version::current().post_vm_init_hook_enabled()) {
4016 call_postVMInitHook(THREAD);
4017 // The Java side of PostVMInitHook.run must deal with all
4018 // exceptions and provide means of diagnosis.
4019 if (HAS_PENDING_EXCEPTION) {
4020 CLEAR_PENDING_EXCEPTION;
4021 }
4022 }
4023
4024 {
4025 MutexLocker ml(PeriodicTask_lock);
4026 // Make sure the WatcherThread can be started by WatcherThread::start()
4027 // or by dynamic enrollment.
4028 WatcherThread::make_startable();
4029 // Start up the WatcherThread if there are any periodic tasks
4030 // NOTE: All PeriodicTasks should be registered by now. If they
4031 // aren't, late joiners might appear to start slowly (we might
4032 // take a while to process their first tick).
4033 if (PeriodicTask::num_tasks() > 0) {
4034 WatcherThread::start();
4035 }
4036 }
4037
4038 create_vm_timer.end();
4039 #ifdef ASSERT
4040 _vm_complete = true;
4041 #endif
4042
4043 if (DumpSharedSpaces) {
4044 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
4045 ShouldNotReachHere();
4046 }
4047
4048 return JNI_OK;
4049 }
4050
4051 // type for the Agent_OnLoad and JVM_OnLoad entry points
4052 extern "C" {
4053 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
4054 }
4055 // Find a command line agent library and return its entry point for
4056 // -agentlib: -agentpath: -Xrun
4057 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
4058 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
4059 const char *on_load_symbols[],
4060 size_t num_symbol_entries) {
4061 OnLoadEntry_t on_load_entry = NULL;
4062 void *library = NULL;
4063
4064 if (!agent->valid()) {
4065 char buffer[JVM_MAXPATHLEN];
4066 char ebuf[1024] = "";
4067 const char *name = agent->name();
4068 const char *msg = "Could not find agent library ";
4069
4070 // First check to see if agent is statically linked into executable
4071 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
4072 library = agent->os_lib();
4073 } else if (agent->is_absolute_path()) {
4074 library = os::dll_load(name, ebuf, sizeof ebuf);
4075 if (library == NULL) {
4076 const char *sub_msg = " in absolute path, with error: ";
4077 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4078 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4079 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4080 // If we can't find the agent, exit.
4081 vm_exit_during_initialization(buf, NULL);
4082 FREE_C_HEAP_ARRAY(char, buf);
4083 }
4084 } else {
4085 // Try to load the agent from the standard dll directory
4086 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4087 name)) {
4088 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4089 }
4090 if (library == NULL) { // Try the library path directory.
4091 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4092 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4093 }
4094 if (library == NULL) {
4095 const char *sub_msg = " on the library path, with error: ";
4096 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4097
4098 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4099 strlen(ebuf) + strlen(sub_msg2) + 1;
4100 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4101 if (!agent->is_instrument_lib()) {
4102 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4103 } else {
4104 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4105 }
4106 // If we can't find the agent, exit.
4107 vm_exit_during_initialization(buf, NULL);
4108 FREE_C_HEAP_ARRAY(char, buf);
4109 }
4110 }
4111 }
4112 agent->set_os_lib(library);
4113 agent->set_valid();
4114 }
4115
4116 // Find the OnLoad function.
4117 on_load_entry =
4118 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4119 false,
4120 on_load_symbols,
4121 num_symbol_entries));
4122 return on_load_entry;
4123 }
4124
4125 // Find the JVM_OnLoad entry point
4126 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4127 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4128 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4129 }
4130
4131 // Find the Agent_OnLoad entry point
4132 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4133 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4134 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4135 }
4136
4137 // For backwards compatibility with -Xrun
4138 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4139 // treated like -agentpath:
4140 // Must be called before agent libraries are created
4141 void Threads::convert_vm_init_libraries_to_agents() {
4142 AgentLibrary* agent;
4143 AgentLibrary* next;
4144
4145 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4146 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4147 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4148
4149 // If there is an JVM_OnLoad function it will get called later,
4150 // otherwise see if there is an Agent_OnLoad
4151 if (on_load_entry == NULL) {
4152 on_load_entry = lookup_agent_on_load(agent);
4153 if (on_load_entry != NULL) {
4154 // switch it to the agent list -- so that Agent_OnLoad will be called,
4155 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4156 Arguments::convert_library_to_agent(agent);
4157 } else {
4158 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4159 }
4160 }
4161 }
4162 }
4163
4164 // Create agents for -agentlib: -agentpath: and converted -Xrun
4165 // Invokes Agent_OnLoad
4166 // Called very early -- before JavaThreads exist
4167 void Threads::create_vm_init_agents() {
4168 extern struct JavaVM_ main_vm;
4169 AgentLibrary* agent;
4170
4171 JvmtiExport::enter_onload_phase();
4172
4173 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4174 // CDS dumping does not support native JVMTI agent.
4175 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
4176 if (DumpSharedSpaces) {
4177 if(!agent->is_instrument_lib()) {
4178 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
4179 } else if (!AllowArchivingWithJavaAgent) {
4180 vm_exit_during_cds_dumping(
4181 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
4182 }
4183 }
4184
4185 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4186
4187 if (on_load_entry != NULL) {
4188 // Invoke the Agent_OnLoad function
4189 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4190 if (err != JNI_OK) {
4191 vm_exit_during_initialization("agent library failed to init", agent->name());
4192 }
4193 } else {
4194 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4195 }
4196 }
4197
4198 JvmtiExport::enter_primordial_phase();
4199 }
4200
4201 extern "C" {
4202 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4203 }
4204
4205 void Threads::shutdown_vm_agents() {
4206 // Send any Agent_OnUnload notifications
4207 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4208 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4209 extern struct JavaVM_ main_vm;
4210 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4211
4212 // Find the Agent_OnUnload function.
4213 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4214 os::find_agent_function(agent,
4215 false,
4216 on_unload_symbols,
4217 num_symbol_entries));
4218
4219 // Invoke the Agent_OnUnload function
4220 if (unload_entry != NULL) {
4221 JavaThread* thread = JavaThread::current();
4222 ThreadToNativeFromVM ttn(thread);
4223 HandleMark hm(thread);
4224 (*unload_entry)(&main_vm);
4225 }
4226 }
4227 }
4228
4229 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4230 // Invokes JVM_OnLoad
4231 void Threads::create_vm_init_libraries() {
4232 extern struct JavaVM_ main_vm;
4233 AgentLibrary* agent;
4234
4235 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4236 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4237
4238 if (on_load_entry != NULL) {
4239 // Invoke the JVM_OnLoad function
4240 JavaThread* thread = JavaThread::current();
4241 ThreadToNativeFromVM ttn(thread);
4242 HandleMark hm(thread);
4243 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4244 if (err != JNI_OK) {
4245 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4246 }
4247 } else {
4248 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4249 }
4250 }
4251 }
4252
4253
4254 // Last thread running calls java.lang.Shutdown.shutdown()
4255 void JavaThread::invoke_shutdown_hooks() {
4256 HandleMark hm(this);
4257
4258 // We could get here with a pending exception, if so clear it now.
4259 if (this->has_pending_exception()) {
4260 this->clear_pending_exception();
4261 }
4262
4263 EXCEPTION_MARK;
4264 Klass* shutdown_klass =
4265 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4266 THREAD);
4267 if (shutdown_klass != NULL) {
4268 // SystemDictionary::resolve_or_null will return null if there was
4269 // an exception. If we cannot load the Shutdown class, just don't
4270 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4271 // won't be run. Note that if a shutdown hook was registered,
4272 // the Shutdown class would have already been loaded
4273 // (Runtime.addShutdownHook will load it).
4274 JavaValue result(T_VOID);
4275 JavaCalls::call_static(&result,
4276 shutdown_klass,
4277 vmSymbols::shutdown_method_name(),
4278 vmSymbols::void_method_signature(),
4279 THREAD);
4280 }
4281 CLEAR_PENDING_EXCEPTION;
4282 }
4283
4284 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4285 // the program falls off the end of main(). Another VM exit path is through
4286 // vm_exit() when the program calls System.exit() to return a value or when
4287 // there is a serious error in VM. The two shutdown paths are not exactly
4288 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4289 // and VM_Exit op at VM level.
4290 //
4291 // Shutdown sequence:
4292 // + Shutdown native memory tracking if it is on
4293 // + Wait until we are the last non-daemon thread to execute
4294 // <-- every thing is still working at this moment -->
4295 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4296 // shutdown hooks
4297 // + Call before_exit(), prepare for VM exit
4298 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4299 // currently the only user of this mechanism is File.deleteOnExit())
4300 // > stop StatSampler, watcher thread, CMS threads,
4301 // post thread end and vm death events to JVMTI,
4302 // stop signal thread
4303 // + Call JavaThread::exit(), it will:
4304 // > release JNI handle blocks, remove stack guard pages
4305 // > remove this thread from Threads list
4306 // <-- no more Java code from this thread after this point -->
4307 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4308 // the compiler threads at safepoint
4309 // <-- do not use anything that could get blocked by Safepoint -->
4310 // + Disable tracing at JNI/JVM barriers
4311 // + Set _vm_exited flag for threads that are still running native code
4312 // + Call exit_globals()
4313 // > deletes tty
4314 // > deletes PerfMemory resources
4315 // + Delete this thread
4316 // + Return to caller
4317
4318 bool Threads::destroy_vm() {
4319 JavaThread* thread = JavaThread::current();
4320
4321 #ifdef ASSERT
4322 _vm_complete = false;
4323 #endif
4324 // Wait until we are the last non-daemon thread to execute
4325 { MutexLocker nu(Threads_lock);
4326 while (Threads::number_of_non_daemon_threads() > 1)
4327 // This wait should make safepoint checks, wait without a timeout,
4328 // and wait as a suspend-equivalent condition.
4329 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4330 Mutex::_as_suspend_equivalent_flag);
4331 }
4332
4333 EventShutdown e;
4334 if (e.should_commit()) {
4335 e.set_reason("No remaining non-daemon Java threads");
4336 e.commit();
4337 }
4338
4339 // Hang forever on exit if we are reporting an error.
4340 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4341 os::infinite_sleep();
4342 }
4343 os::wait_for_keypress_at_exit();
4344
4345 // run Java level shutdown hooks
4346 thread->invoke_shutdown_hooks();
4347
4348 before_exit(thread);
4349
4350 thread->exit(true);
4351
4352 // Stop VM thread.
4353 {
4354 // 4945125 The vm thread comes to a safepoint during exit.
4355 // GC vm_operations can get caught at the safepoint, and the
4356 // heap is unparseable if they are caught. Grab the Heap_lock
4357 // to prevent this. The GC vm_operations will not be able to
4358 // queue until after the vm thread is dead. After this point,
4359 // we'll never emerge out of the safepoint before the VM exits.
4360
4361 MutexLockerEx ml(Heap_lock, Mutex::_no_safepoint_check_flag);
4362
4363 VMThread::wait_for_vm_thread_exit();
4364 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4365 VMThread::destroy();
4366 }
4367
4368 // Now, all Java threads are gone except daemon threads. Daemon threads
4369 // running Java code or in VM are stopped by the Safepoint. However,
4370 // daemon threads executing native code are still running. But they
4371 // will be stopped at native=>Java/VM barriers. Note that we can't
4372 // simply kill or suspend them, as it is inherently deadlock-prone.
4373
4374 VM_Exit::set_vm_exited();
4375
4376 // Clean up ideal graph printers after the VMThread has started
4377 // the final safepoint which will block all the Compiler threads.
4378 // Note that this Thread has already logically exited so the
4379 // clean_up() function's use of a JavaThreadIteratorWithHandle
4380 // would be a problem except set_vm_exited() has remembered the
4381 // shutdown thread which is granted a policy exception.
4382 #if defined(COMPILER2) && !defined(PRODUCT)
4383 IdealGraphPrinter::clean_up();
4384 #endif
4385
4386 notify_vm_shutdown();
4387
4388 // exit_globals() will delete tty
4389 exit_globals();
4390
4391 // We are after VM_Exit::set_vm_exited() so we can't call
4392 // thread->smr_delete() or we will block on the Threads_lock.
4393 // Deleting the shutdown thread here is safe because another
4394 // JavaThread cannot have an active ThreadsListHandle for
4395 // this JavaThread.
4396 delete thread;
4397
4398 #if INCLUDE_JVMCI
4399 if (JVMCICounterSize > 0) {
4400 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4401 }
4402 #endif
4403
4404 LogConfiguration::finalize();
4405
4406 return true;
4407 }
4408
4409
4410 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4411 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4412 return is_supported_jni_version(version);
4413 }
4414
4415
4416 jboolean Threads::is_supported_jni_version(jint version) {
4417 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4418 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4419 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4420 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4421 if (version == JNI_VERSION_9) return JNI_TRUE;
4422 if (version == JNI_VERSION_10) return JNI_TRUE;
4423 return JNI_FALSE;
4424 }
4425
4426
4427 void Threads::add(JavaThread* p, bool force_daemon) {
4428 // The threads lock must be owned at this point
4429 assert(Threads_lock->owned_by_self(), "must have threads lock");
4430
4431 BarrierSet::barrier_set()->on_thread_attach(p);
4432
4433 p->set_next(_thread_list);
4434 _thread_list = p;
4435
4436 // Once a JavaThread is added to the Threads list, smr_delete() has
4437 // to be used to delete it. Otherwise we can just delete it directly.
4438 p->set_on_thread_list();
4439
4440 _number_of_threads++;
4441 oop threadObj = p->threadObj();
4442 bool daemon = true;
4443 // Bootstrapping problem: threadObj can be null for initial
4444 // JavaThread (or for threads attached via JNI)
4445 if ((!force_daemon) && !is_daemon((threadObj))) {
4446 _number_of_non_daemon_threads++;
4447 daemon = false;
4448 }
4449
4450 ThreadService::add_thread(p, daemon);
4451
4452 // Maintain fast thread list
4453 ThreadsSMRSupport::add_thread(p);
4454
4455 // Possible GC point.
4456 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4457 }
4458
4459 void Threads::remove(JavaThread* p) {
4460
4461 // Reclaim the ObjectMonitors from the omInUseList and omFreeList of the moribund thread.
4462 ObjectSynchronizer::omFlush(p);
4463
4464 // Extra scope needed for Thread_lock, so we can check
4465 // that we do not remove thread without safepoint code notice
4466 { MutexLocker ml(Threads_lock);
4467
4468 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4469
4470 // Maintain fast thread list
4471 ThreadsSMRSupport::remove_thread(p);
4472
4473 JavaThread* current = _thread_list;
4474 JavaThread* prev = NULL;
4475
4476 while (current != p) {
4477 prev = current;
4478 current = current->next();
4479 }
4480
4481 if (prev) {
4482 prev->set_next(current->next());
4483 } else {
4484 _thread_list = p->next();
4485 }
4486
4487 _number_of_threads--;
4488 oop threadObj = p->threadObj();
4489 bool daemon = true;
4490 if (!is_daemon(threadObj)) {
4491 _number_of_non_daemon_threads--;
4492 daemon = false;
4493
4494 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4495 // on destroy_vm will wake up.
4496 if (number_of_non_daemon_threads() == 1) {
4497 Threads_lock->notify_all();
4498 }
4499 }
4500 ThreadService::remove_thread(p, daemon);
4501
4502 // Make sure that safepoint code disregard this thread. This is needed since
4503 // the thread might mess around with locks after this point. This can cause it
4504 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4505 // of this thread since it is removed from the queue.
4506 p->set_terminated_value();
4507 } // unlock Threads_lock
4508
4509 // Since Events::log uses a lock, we grab it outside the Threads_lock
4510 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4511 }
4512
4513 // Operations on the Threads list for GC. These are not explicitly locked,
4514 // but the garbage collector must provide a safe context for them to run.
4515 // In particular, these things should never be called when the Threads_lock
4516 // is held by some other thread. (Note: the Safepoint abstraction also
4517 // uses the Threads_lock to guarantee this property. It also makes sure that
4518 // all threads gets blocked when exiting or starting).
4519
4520 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4521 ALL_JAVA_THREADS(p) {
4522 p->oops_do(f, cf);
4523 }
4524 VMThread::vm_thread()->oops_do(f, cf);
4525 }
4526
4527 void Threads::change_thread_claim_parity() {
4528 // Set the new claim parity.
4529 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4530 "Not in range.");
4531 _thread_claim_parity++;
4532 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4533 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4534 "Not in range.");
4535 }
4536
4537 #ifdef ASSERT
4538 void Threads::assert_all_threads_claimed() {
4539 ALL_JAVA_THREADS(p) {
4540 const int thread_parity = p->oops_do_parity();
4541 assert((thread_parity == _thread_claim_parity),
4542 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4543 }
4544 VMThread* vmt = VMThread::vm_thread();
4545 const int thread_parity = vmt->oops_do_parity();
4546 assert((thread_parity == _thread_claim_parity),
4547 "VMThread " PTR_FORMAT " has incorrect parity %d != %d", p2i(vmt), thread_parity, _thread_claim_parity);
4548 }
4549 #endif // ASSERT
4550
4551 class ParallelOopsDoThreadClosure : public ThreadClosure {
4552 private:
4553 OopClosure* _f;
4554 CodeBlobClosure* _cf;
4555 public:
4556 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4557 void do_thread(Thread* t) {
4558 t->oops_do(_f, _cf);
4559 }
4560 };
4561
4562 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4563 ParallelOopsDoThreadClosure tc(f, cf);
4564 possibly_parallel_threads_do(is_par, &tc);
4565 }
4566
4567 void Threads::nmethods_do(CodeBlobClosure* cf) {
4568 ALL_JAVA_THREADS(p) {
4569 // This is used by the code cache sweeper to mark nmethods that are active
4570 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4571 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4572 if(!p->is_Code_cache_sweeper_thread()) {
4573 p->nmethods_do(cf);
4574 }
4575 }
4576 }
4577
4578 void Threads::metadata_do(void f(Metadata*)) {
4579 ALL_JAVA_THREADS(p) {
4580 p->metadata_do(f);
4581 }
4582 }
4583
4584 class ThreadHandlesClosure : public ThreadClosure {
4585 void (*_f)(Metadata*);
4586 public:
4587 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4588 virtual void do_thread(Thread* thread) {
4589 thread->metadata_handles_do(_f);
4590 }
4591 };
4592
4593 void Threads::metadata_handles_do(void f(Metadata*)) {
4594 // Only walk the Handles in Thread.
4595 ThreadHandlesClosure handles_closure(f);
4596 threads_do(&handles_closure);
4597 }
4598
4599 void Threads::deoptimized_wrt_marked_nmethods() {
4600 ALL_JAVA_THREADS(p) {
4601 p->deoptimized_wrt_marked_nmethods();
4602 }
4603 }
4604
4605
4606 // Get count Java threads that are waiting to enter the specified monitor.
4607 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4608 int count,
4609 address monitor) {
4610 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4611
4612 int i = 0;
4613 DO_JAVA_THREADS(t_list, p) {
4614 if (!p->can_call_java()) continue;
4615
4616 address pending = (address)p->current_pending_monitor();
4617 if (pending == monitor) { // found a match
4618 if (i < count) result->append(p); // save the first count matches
4619 i++;
4620 }
4621 }
4622
4623 return result;
4624 }
4625
4626
4627 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4628 address owner) {
4629 // NULL owner means not locked so we can skip the search
4630 if (owner == NULL) return NULL;
4631
4632 DO_JAVA_THREADS(t_list, p) {
4633 // first, see if owner is the address of a Java thread
4634 if (owner == (address)p) return p;
4635 }
4636
4637 // Cannot assert on lack of success here since this function may be
4638 // used by code that is trying to report useful problem information
4639 // like deadlock detection.
4640 if (UseHeavyMonitors) return NULL;
4641
4642 // If we didn't find a matching Java thread and we didn't force use of
4643 // heavyweight monitors, then the owner is the stack address of the
4644 // Lock Word in the owning Java thread's stack.
4645 //
4646 JavaThread* the_owner = NULL;
4647 DO_JAVA_THREADS(t_list, q) {
4648 if (q->is_lock_owned(owner)) {
4649 the_owner = q;
4650 break;
4651 }
4652 }
4653
4654 // cannot assert on lack of success here; see above comment
4655 return the_owner;
4656 }
4657
4658 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4659 void Threads::print_on(outputStream* st, bool print_stacks,
4660 bool internal_format, bool print_concurrent_locks,
4661 bool print_extended_info) {
4662 char buf[32];
4663 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4664
4665 st->print_cr("Full thread dump %s (%s %s):",
4666 VM_Version::vm_name(),
4667 VM_Version::vm_release(),
4668 VM_Version::vm_info_string());
4669 st->cr();
4670
4671 #if INCLUDE_SERVICES
4672 // Dump concurrent locks
4673 ConcurrentLocksDump concurrent_locks;
4674 if (print_concurrent_locks) {
4675 concurrent_locks.dump_at_safepoint();
4676 }
4677 #endif // INCLUDE_SERVICES
4678
4679 ThreadsSMRSupport::print_info_on(st);
4680 st->cr();
4681
4682 ALL_JAVA_THREADS(p) {
4683 ResourceMark rm;
4684 p->print_on(st, print_extended_info);
4685 if (print_stacks) {
4686 if (internal_format) {
4687 p->trace_stack();
4688 } else {
4689 p->print_stack_on(st);
4690 }
4691 }
4692 st->cr();
4693 #if INCLUDE_SERVICES
4694 if (print_concurrent_locks) {
4695 concurrent_locks.print_locks_on(p, st);
4696 }
4697 #endif // INCLUDE_SERVICES
4698 }
4699
4700 VMThread::vm_thread()->print_on(st);
4701 st->cr();
4702 Universe::heap()->print_gc_threads_on(st);
4703 WatcherThread* wt = WatcherThread::watcher_thread();
4704 if (wt != NULL) {
4705 wt->print_on(st);
4706 st->cr();
4707 }
4708
4709 st->flush();
4710 }
4711
4712 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4713 int buflen, bool* found_current) {
4714 if (this_thread != NULL) {
4715 bool is_current = (current == this_thread);
4716 *found_current = *found_current || is_current;
4717 st->print("%s", is_current ? "=>" : " ");
4718
4719 st->print(PTR_FORMAT, p2i(this_thread));
4720 st->print(" ");
4721 this_thread->print_on_error(st, buf, buflen);
4722 st->cr();
4723 }
4724 }
4725
4726 class PrintOnErrorClosure : public ThreadClosure {
4727 outputStream* _st;
4728 Thread* _current;
4729 char* _buf;
4730 int _buflen;
4731 bool* _found_current;
4732 public:
4733 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4734 int buflen, bool* found_current) :
4735 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4736
4737 virtual void do_thread(Thread* thread) {
4738 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4739 }
4740 };
4741
4742 // Threads::print_on_error() is called by fatal error handler. It's possible
4743 // that VM is not at safepoint and/or current thread is inside signal handler.
4744 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4745 // memory (even in resource area), it might deadlock the error handler.
4746 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4747 int buflen) {
4748 ThreadsSMRSupport::print_info_on(st);
4749 st->cr();
4750
4751 bool found_current = false;
4752 st->print_cr("Java Threads: ( => current thread )");
4753 ALL_JAVA_THREADS(thread) {
4754 print_on_error(thread, st, current, buf, buflen, &found_current);
4755 }
4756 st->cr();
4757
4758 st->print_cr("Other Threads:");
4759 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4760 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4761
4762 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4763 Universe::heap()->gc_threads_do(&print_closure);
4764
4765 if (!found_current) {
4766 st->cr();
4767 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4768 current->print_on_error(st, buf, buflen);
4769 st->cr();
4770 }
4771 st->cr();
4772
4773 st->print_cr("Threads with active compile tasks:");
4774 print_threads_compiling(st, buf, buflen);
4775 }
4776
4777 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
4778 ALL_JAVA_THREADS(thread) {
4779 if (thread->is_Compiler_thread()) {
4780 CompilerThread* ct = (CompilerThread*) thread;
4781
4782 // Keep task in local variable for NULL check.
4783 // ct->_task might be set to NULL by concurring compiler thread
4784 // because it completed the compilation. The task is never freed,
4785 // though, just returned to a free list.
4786 CompileTask* task = ct->task();
4787 if (task != NULL) {
4788 thread->print_name_on_error(st, buf, buflen);
4789 st->print(" ");
4790 task->print(st, NULL, short_form, true);
4791 }
4792 }
4793 }
4794 }
4795
4796
4797 // Internal SpinLock and Mutex
4798 // Based on ParkEvent
4799
4800 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4801 //
4802 // We employ SpinLocks _only for low-contention, fixed-length
4803 // short-duration critical sections where we're concerned
4804 // about native mutex_t or HotSpot Mutex:: latency.
4805 // The mux construct provides a spin-then-block mutual exclusion
4806 // mechanism.
4807 //
4808 // Testing has shown that contention on the ListLock guarding gFreeList
4809 // is common. If we implement ListLock as a simple SpinLock it's common
4810 // for the JVM to devolve to yielding with little progress. This is true
4811 // despite the fact that the critical sections protected by ListLock are
4812 // extremely short.
4813 //
4814 // TODO-FIXME: ListLock should be of type SpinLock.
4815 // We should make this a 1st-class type, integrated into the lock
4816 // hierarchy as leaf-locks. Critically, the SpinLock structure
4817 // should have sufficient padding to avoid false-sharing and excessive
4818 // cache-coherency traffic.
4819
4820
4821 typedef volatile int SpinLockT;
4822
4823 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4824 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4825 return; // normal fast-path return
4826 }
4827
4828 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4829 int ctr = 0;
4830 int Yields = 0;
4831 for (;;) {
4832 while (*adr != 0) {
4833 ++ctr;
4834 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4835 if (Yields > 5) {
4836 os::naked_short_sleep(1);
4837 } else {
4838 os::naked_yield();
4839 ++Yields;
4840 }
4841 } else {
4842 SpinPause();
4843 }
4844 }
4845 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4846 }
4847 }
4848
4849 void Thread::SpinRelease(volatile int * adr) {
4850 assert(*adr != 0, "invariant");
4851 OrderAccess::fence(); // guarantee at least release consistency.
4852 // Roach-motel semantics.
4853 // It's safe if subsequent LDs and STs float "up" into the critical section,
4854 // but prior LDs and STs within the critical section can't be allowed
4855 // to reorder or float past the ST that releases the lock.
4856 // Loads and stores in the critical section - which appear in program
4857 // order before the store that releases the lock - must also appear
4858 // before the store that releases the lock in memory visibility order.
4859 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4860 // the ST of 0 into the lock-word which releases the lock, so fence
4861 // more than covers this on all platforms.
4862 *adr = 0;
4863 }
4864
4865 // muxAcquire and muxRelease:
4866 //
4867 // * muxAcquire and muxRelease support a single-word lock-word construct.
4868 // The LSB of the word is set IFF the lock is held.
4869 // The remainder of the word points to the head of a singly-linked list
4870 // of threads blocked on the lock.
4871 //
4872 // * The current implementation of muxAcquire-muxRelease uses its own
4873 // dedicated Thread._MuxEvent instance. If we're interested in
4874 // minimizing the peak number of extant ParkEvent instances then
4875 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4876 // as certain invariants were satisfied. Specifically, care would need
4877 // to be taken with regards to consuming unpark() "permits".
4878 // A safe rule of thumb is that a thread would never call muxAcquire()
4879 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4880 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4881 // consume an unpark() permit intended for monitorenter, for instance.
4882 // One way around this would be to widen the restricted-range semaphore
4883 // implemented in park(). Another alternative would be to provide
4884 // multiple instances of the PlatformEvent() for each thread. One
4885 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4886 //
4887 // * Usage:
4888 // -- Only as leaf locks
4889 // -- for short-term locking only as muxAcquire does not perform
4890 // thread state transitions.
4891 //
4892 // Alternatives:
4893 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4894 // but with parking or spin-then-park instead of pure spinning.
4895 // * Use Taura-Oyama-Yonenzawa locks.
4896 // * It's possible to construct a 1-0 lock if we encode the lockword as
4897 // (List,LockByte). Acquire will CAS the full lockword while Release
4898 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4899 // acquiring threads use timers (ParkTimed) to detect and recover from
4900 // the stranding window. Thread/Node structures must be aligned on 256-byte
4901 // boundaries by using placement-new.
4902 // * Augment MCS with advisory back-link fields maintained with CAS().
4903 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4904 // The validity of the backlinks must be ratified before we trust the value.
4905 // If the backlinks are invalid the exiting thread must back-track through the
4906 // the forward links, which are always trustworthy.
4907 // * Add a successor indication. The LockWord is currently encoded as
4908 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4909 // to provide the usual futile-wakeup optimization.
4910 // See RTStt for details.
4911 //
4912
4913
4914 const intptr_t LOCKBIT = 1;
4915
4916 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4917 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4918 if (w == 0) return;
4919 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4920 return;
4921 }
4922
4923 ParkEvent * const Self = Thread::current()->_MuxEvent;
4924 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4925 for (;;) {
4926 int its = (os::is_MP() ? 100 : 0) + 1;
4927
4928 // Optional spin phase: spin-then-park strategy
4929 while (--its >= 0) {
4930 w = *Lock;
4931 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4932 return;
4933 }
4934 }
4935
4936 Self->reset();
4937 Self->OnList = intptr_t(Lock);
4938 // The following fence() isn't _strictly necessary as the subsequent
4939 // CAS() both serializes execution and ratifies the fetched *Lock value.
4940 OrderAccess::fence();
4941 for (;;) {
4942 w = *Lock;
4943 if ((w & LOCKBIT) == 0) {
4944 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4945 Self->OnList = 0; // hygiene - allows stronger asserts
4946 return;
4947 }
4948 continue; // Interference -- *Lock changed -- Just retry
4949 }
4950 assert(w & LOCKBIT, "invariant");
4951 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4952 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4953 }
4954
4955 while (Self->OnList != 0) {
4956 Self->park();
4957 }
4958 }
4959 }
4960
4961 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4962 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4963 if (w == 0) return;
4964 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4965 return;
4966 }
4967
4968 ParkEvent * ReleaseAfter = NULL;
4969 if (ev == NULL) {
4970 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4971 }
4972 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4973 for (;;) {
4974 guarantee(ev->OnList == 0, "invariant");
4975 int its = (os::is_MP() ? 100 : 0) + 1;
4976
4977 // Optional spin phase: spin-then-park strategy
4978 while (--its >= 0) {
4979 w = *Lock;
4980 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4981 if (ReleaseAfter != NULL) {
4982 ParkEvent::Release(ReleaseAfter);
4983 }
4984 return;
4985 }
4986 }
4987
4988 ev->reset();
4989 ev->OnList = intptr_t(Lock);
4990 // The following fence() isn't _strictly necessary as the subsequent
4991 // CAS() both serializes execution and ratifies the fetched *Lock value.
4992 OrderAccess::fence();
4993 for (;;) {
4994 w = *Lock;
4995 if ((w & LOCKBIT) == 0) {
4996 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4997 ev->OnList = 0;
4998 // We call ::Release while holding the outer lock, thus
4999 // artificially lengthening the critical section.
5000 // Consider deferring the ::Release() until the subsequent unlock(),
5001 // after we've dropped the outer lock.
5002 if (ReleaseAfter != NULL) {
5003 ParkEvent::Release(ReleaseAfter);
5004 }
5005 return;
5006 }
5007 continue; // Interference -- *Lock changed -- Just retry
5008 }
5009 assert(w & LOCKBIT, "invariant");
5010 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
5011 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
5012 }
5013
5014 while (ev->OnList != 0) {
5015 ev->park();
5016 }
5017 }
5018 }
5019
5020 // Release() must extract a successor from the list and then wake that thread.
5021 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
5022 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
5023 // Release() would :
5024 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
5025 // (B) Extract a successor from the private list "in-hand"
5026 // (C) attempt to CAS() the residual back into *Lock over null.
5027 // If there were any newly arrived threads and the CAS() would fail.
5028 // In that case Release() would detach the RATs, re-merge the list in-hand
5029 // with the RATs and repeat as needed. Alternately, Release() might
5030 // detach and extract a successor, but then pass the residual list to the wakee.
5031 // The wakee would be responsible for reattaching and remerging before it
5032 // competed for the lock.
5033 //
5034 // Both "pop" and DMR are immune from ABA corruption -- there can be
5035 // multiple concurrent pushers, but only one popper or detacher.
5036 // This implementation pops from the head of the list. This is unfair,
5037 // but tends to provide excellent throughput as hot threads remain hot.
5038 // (We wake recently run threads first).
5039 //
5040 // All paths through muxRelease() will execute a CAS.
5041 // Release consistency -- We depend on the CAS in muxRelease() to provide full
5042 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
5043 // executed within the critical section are complete and globally visible before the
5044 // store (CAS) to the lock-word that releases the lock becomes globally visible.
5045 void Thread::muxRelease(volatile intptr_t * Lock) {
5046 for (;;) {
5047 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
5048 assert(w & LOCKBIT, "invariant");
5049 if (w == LOCKBIT) return;
5050 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
5051 assert(List != NULL, "invariant");
5052 assert(List->OnList == intptr_t(Lock), "invariant");
5053 ParkEvent * const nxt = List->ListNext;
5054 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5055
5056 // The following CAS() releases the lock and pops the head element.
5057 // The CAS() also ratifies the previously fetched lock-word value.
5058 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
5059 continue;
5060 }
5061 List->OnList = 0;
5062 OrderAccess::fence();
5063 List->unpark();
5064 return;
5065 }
5066 }
5067
5068
5069 void Threads::verify() {
5070 ALL_JAVA_THREADS(p) {
5071 p->verify();
5072 }
5073 VMThread* thread = VMThread::vm_thread();
5074 if (thread != NULL) thread->verify();
5075 }