1 /*
2 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/moduleEntry.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "classfile/vmSymbols.hpp"
32 #include "code/codeCache.hpp"
33 #include "code/scopeDesc.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "compiler/compileTask.hpp"
36 #include "gc/shared/barrierSet.hpp"
37 #include "gc/shared/gcId.hpp"
38 #include "gc/shared/gcLocker.inline.hpp"
39 #include "gc/shared/workgroup.hpp"
40 #include "interpreter/interpreter.hpp"
41 #include "interpreter/linkResolver.hpp"
42 #include "interpreter/oopMapCache.hpp"
43 #include "jfr/jfrEvents.hpp"
44 #include "jvmtifiles/jvmtiEnv.hpp"
45 #include "logging/log.hpp"
46 #include "logging/logConfiguration.hpp"
47 #include "logging/logStream.hpp"
48 #include "memory/allocation.inline.hpp"
49 #include "memory/metaspaceShared.hpp"
50 #include "memory/oopFactory.hpp"
51 #include "memory/resourceArea.hpp"
52 #include "memory/universe.hpp"
53 #include "oops/access.inline.hpp"
54 #include "oops/instanceKlass.hpp"
55 #include "oops/objArrayOop.hpp"
56 #include "oops/oop.inline.hpp"
57 #include "oops/symbol.hpp"
58 #include "oops/typeArrayOop.inline.hpp"
59 #include "oops/verifyOopClosure.hpp"
60 #include "prims/jvm_misc.hpp"
61 #include "prims/jvmtiExport.hpp"
62 #include "prims/jvmtiThreadState.hpp"
63 #include "runtime/arguments.hpp"
64 #include "runtime/atomic.hpp"
65 #include "runtime/biasedLocking.hpp"
66 #include "runtime/fieldDescriptor.inline.hpp"
67 #include "runtime/flags/jvmFlagConstraintList.hpp"
68 #include "runtime/flags/jvmFlagRangeList.hpp"
69 #include "runtime/flags/jvmFlagWriteableList.hpp"
70 #include "runtime/deoptimization.hpp"
71 #include "runtime/frame.inline.hpp"
72 #include "runtime/handles.inline.hpp"
73 #include "runtime/handshake.hpp"
74 #include "runtime/init.hpp"
75 #include "runtime/interfaceSupport.inline.hpp"
76 #include "runtime/java.hpp"
77 #include "runtime/javaCalls.hpp"
78 #include "runtime/jniHandles.inline.hpp"
79 #include "runtime/jniPeriodicChecker.hpp"
80 #include "runtime/memprofiler.hpp"
81 #include "runtime/mutexLocker.hpp"
82 #include "runtime/objectMonitor.hpp"
83 #include "runtime/orderAccess.hpp"
84 #include "runtime/osThread.hpp"
85 #include "runtime/prefetch.inline.hpp"
86 #include "runtime/safepoint.hpp"
87 #include "runtime/safepointMechanism.inline.hpp"
88 #include "runtime/safepointVerifiers.hpp"
89 #include "runtime/sharedRuntime.hpp"
90 #include "runtime/statSampler.hpp"
91 #include "runtime/stubRoutines.hpp"
92 #include "runtime/sweeper.hpp"
93 #include "runtime/task.hpp"
94 #include "runtime/thread.inline.hpp"
95 #include "runtime/threadCritical.hpp"
96 #include "runtime/threadSMR.inline.hpp"
97 #include "runtime/threadStatisticalInfo.hpp"
98 #include "runtime/timer.hpp"
99 #include "runtime/timerTrace.hpp"
100 #include "runtime/vframe.inline.hpp"
101 #include "runtime/vframeArray.hpp"
102 #include "runtime/vframe_hp.hpp"
103 #include "runtime/vmThread.hpp"
104 #include "runtime/vmOperations.hpp"
105 #include "runtime/vm_version.hpp"
106 #include "services/attachListener.hpp"
107 #include "services/management.hpp"
108 #include "services/memTracker.hpp"
109 #include "services/threadService.hpp"
110 #include "utilities/align.hpp"
111 #include "utilities/copy.hpp"
112 #include "utilities/defaultStream.hpp"
113 #include "utilities/dtrace.hpp"
114 #include "utilities/events.hpp"
115 #include "utilities/macros.hpp"
116 #include "utilities/preserveException.hpp"
117 #include "utilities/singleWriterSynchronizer.hpp"
118 #include "utilities/vmError.hpp"
119 #if INCLUDE_JVMCI
120 #include "jvmci/jvmciCompiler.hpp"
121 #include "jvmci/jvmciRuntime.hpp"
122 #include "logging/logHandle.hpp"
123 #endif
124 #ifdef COMPILER1
125 #include "c1/c1_Compiler.hpp"
126 #endif
127 #ifdef COMPILER2
128 #include "opto/c2compiler.hpp"
129 #include "opto/idealGraphPrinter.hpp"
130 #endif
131 #if INCLUDE_RTM_OPT
132 #include "runtime/rtmLocking.hpp"
133 #endif
134 #if INCLUDE_JFR
135 #include "jfr/jfr.hpp"
136 #endif
137
138 // Initialization after module runtime initialization
139 void universe_post_module_init(); // must happen after call_initPhase2
140
141 #ifdef DTRACE_ENABLED
142
143 // Only bother with this argument setup if dtrace is available
144
145 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
146 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
147
148 #define DTRACE_THREAD_PROBE(probe, javathread) \
149 { \
150 ResourceMark rm(this); \
151 int len = 0; \
152 const char* name = (javathread)->get_thread_name(); \
153 len = strlen(name); \
154 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
155 (char *) name, len, \
156 java_lang_Thread::thread_id((javathread)->threadObj()), \
157 (uintptr_t) (javathread)->osthread()->thread_id(), \
158 java_lang_Thread::is_daemon((javathread)->threadObj())); \
159 }
160
161 #else // ndef DTRACE_ENABLED
162
163 #define DTRACE_THREAD_PROBE(probe, javathread)
164
165 #endif // ndef DTRACE_ENABLED
166
167 #ifndef USE_LIBRARY_BASED_TLS_ONLY
168 // Current thread is maintained as a thread-local variable
169 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
170 #endif
171
172 // ======= Thread ========
173 // Support for forcing alignment of thread objects for biased locking
174 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
175 if (UseBiasedLocking) {
176 const int alignment = markOopDesc::biased_lock_alignment;
177 size_t aligned_size = size + (alignment - sizeof(intptr_t));
178 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
179 : AllocateHeap(aligned_size, flags, CURRENT_PC,
180 AllocFailStrategy::RETURN_NULL);
181 void* aligned_addr = align_up(real_malloc_addr, alignment);
182 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
183 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
184 "JavaThread alignment code overflowed allocated storage");
185 if (aligned_addr != real_malloc_addr) {
186 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
187 p2i(real_malloc_addr),
188 p2i(aligned_addr));
189 }
190 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
191 return aligned_addr;
192 } else {
193 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
194 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
195 }
196 }
197
198 void Thread::operator delete(void* p) {
199 if (UseBiasedLocking) {
200 FreeHeap(((Thread*) p)->_real_malloc_address);
201 } else {
202 FreeHeap(p);
203 }
204 }
205
206 void JavaThread::smr_delete() {
207 if (_on_thread_list) {
208 ThreadsSMRSupport::smr_delete(this);
209 } else {
210 delete this;
211 }
212 }
213
214 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
215 // JavaThread
216
217 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
218
219 Thread::Thread() {
220
221 DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
222
223 // stack and get_thread
224 set_stack_base(NULL);
225 set_stack_size(0);
226 set_self_raw_id(0);
227 set_lgrp_id(-1);
228 DEBUG_ONLY(clear_suspendible_thread();)
229
230 // allocated data structures
231 set_osthread(NULL);
232 set_resource_area(new (mtThread)ResourceArea());
233 DEBUG_ONLY(_current_resource_mark = NULL;)
234 set_handle_area(new (mtThread) HandleArea(NULL));
235 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
236 set_active_handles(NULL);
237 set_free_handle_block(NULL);
238 set_last_handle_mark(NULL);
239 DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
240
241 // This initial value ==> never claimed.
242 _oops_do_parity = 0;
243 _threads_hazard_ptr = NULL;
244 _threads_list_ptr = NULL;
245 _nested_threads_hazard_ptr_cnt = 0;
246 _rcu_counter = 0;
247
248 // the handle mark links itself to last_handle_mark
249 new HandleMark(this);
250
251 // plain initialization
252 debug_only(_owned_locks = NULL;)
253 debug_only(_allow_allocation_count = 0;)
254 NOT_PRODUCT(_allow_safepoint_count = 0;)
255 NOT_PRODUCT(_skip_gcalot = false;)
256 _jvmti_env_iteration_count = 0;
257 set_allocated_bytes(0);
258 _vm_operation_started_count = 0;
259 _vm_operation_completed_count = 0;
260 _current_pending_monitor = NULL;
261 _current_pending_monitor_is_from_java = true;
262 _current_waiting_monitor = NULL;
263 _num_nested_signal = 0;
264 omFreeList = NULL;
265 omFreeCount = 0;
266 omFreeProvision = 32;
267 omInUseList = NULL;
268 omInUseCount = 0;
269
270 #ifdef ASSERT
271 _visited_for_critical_count = false;
272 #endif
273
274 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
275 Monitor::_safepoint_check_sometimes);
276 _suspend_flags = 0;
277
278 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
279 _hashStateX = os::random();
280 _hashStateY = 842502087;
281 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
282 _hashStateW = 273326509;
283
284 _OnTrap = 0;
285 _Stalled = 0;
286 _TypeTag = 0x2BAD;
287
288 // Many of the following fields are effectively final - immutable
289 // Note that nascent threads can't use the Native Monitor-Mutex
290 // construct until the _MutexEvent is initialized ...
291 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
292 // we might instead use a stack of ParkEvents that we could provision on-demand.
293 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
294 // and ::Release()
295 _ParkEvent = ParkEvent::Allocate(this);
296 _SleepEvent = ParkEvent::Allocate(this);
297 _MuxEvent = ParkEvent::Allocate(this);
298
299 #ifdef CHECK_UNHANDLED_OOPS
300 if (CheckUnhandledOops) {
301 _unhandled_oops = new UnhandledOops(this);
302 }
303 #endif // CHECK_UNHANDLED_OOPS
304 #ifdef ASSERT
305 if (UseBiasedLocking) {
306 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
307 assert(this == _real_malloc_address ||
308 this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
309 "bug in forced alignment of thread objects");
310 }
311 #endif // ASSERT
312
313 // Notify the barrier set that a thread is being created. The initial
314 // thread is created before the barrier set is available. The call to
315 // BarrierSet::on_thread_create() for this thread is therefore deferred
316 // to BarrierSet::set_barrier_set().
317 BarrierSet* const barrier_set = BarrierSet::barrier_set();
318 if (barrier_set != NULL) {
319 barrier_set->on_thread_create(this);
320 } else {
321 // Only the main thread should be created before the barrier set
322 // and that happens just before Thread::current is set. No other thread
323 // can attach as the VM is not created yet, so they can't execute this code.
324 // If the main thread creates other threads before the barrier set that is an error.
325 assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
326 }
327 }
328
329 void Thread::initialize_thread_current() {
330 #ifndef USE_LIBRARY_BASED_TLS_ONLY
331 assert(_thr_current == NULL, "Thread::current already initialized");
332 _thr_current = this;
333 #endif
334 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
335 ThreadLocalStorage::set_thread(this);
336 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
337 }
338
339 void Thread::clear_thread_current() {
340 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
341 #ifndef USE_LIBRARY_BASED_TLS_ONLY
342 _thr_current = NULL;
343 #endif
344 ThreadLocalStorage::set_thread(NULL);
345 }
346
347 void Thread::record_stack_base_and_size() {
348 // Note: at this point, Thread object is not yet initialized. Do not rely on
349 // any members being initialized. Do not rely on Thread::current() being set.
350 // If possible, refrain from doing anything which may crash or assert since
351 // quite probably those crash dumps will be useless.
352 set_stack_base(os::current_stack_base());
353 set_stack_size(os::current_stack_size());
354
355 #ifdef SOLARIS
356 if (os::is_primordial_thread()) {
357 os::Solaris::correct_stack_boundaries_for_primordial_thread(this);
358 }
359 #endif
360
361 // Set stack limits after thread is initialized.
362 if (is_Java_thread()) {
363 ((JavaThread*) this)->set_stack_overflow_limit();
364 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
365 }
366 }
367
368 #if INCLUDE_NMT
369 void Thread::register_thread_stack_with_NMT() {
370 MemTracker::record_thread_stack(stack_end(), stack_size());
371 }
372 #endif // INCLUDE_NMT
373
374 void Thread::call_run() {
375 DEBUG_ONLY(_run_state = CALL_RUN;)
376
377 // At this point, Thread object should be fully initialized and
378 // Thread::current() should be set.
379
380 assert(Thread::current_or_null() != NULL, "current thread is unset");
381 assert(Thread::current_or_null() == this, "current thread is wrong");
382
383 // Perform common initialization actions
384
385 register_thread_stack_with_NMT();
386
387 JFR_ONLY(Jfr::on_thread_start(this);)
388
389 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
390 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
391 os::current_thread_id(), p2i(stack_base() - stack_size()),
392 p2i(stack_base()), stack_size()/1024);
393
394 // Perform <ChildClass> initialization actions
395 DEBUG_ONLY(_run_state = PRE_RUN;)
396 this->pre_run();
397
398 // Invoke <ChildClass>::run()
399 DEBUG_ONLY(_run_state = RUN;)
400 this->run();
401 // Returned from <ChildClass>::run(). Thread finished.
402
403 // Perform common tear-down actions
404
405 assert(Thread::current_or_null() != NULL, "current thread is unset");
406 assert(Thread::current_or_null() == this, "current thread is wrong");
407
408 // Perform <ChildClass> tear-down actions
409 DEBUG_ONLY(_run_state = POST_RUN;)
410 this->post_run();
411
412 // Note: at this point the thread object may already have deleted itself,
413 // so from here on do not dereference *this*. Not all thread types currently
414 // delete themselves when they terminate. But no thread should ever be deleted
415 // asynchronously with respect to its termination - that is what _run_state can
416 // be used to check.
417
418 assert(Thread::current_or_null() == NULL, "current thread still present");
419 }
420
421 Thread::~Thread() {
422
423 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
424 // get started due to errors etc. Any active thread should at least reach post_run
425 // before it is deleted (usually in post_run()).
426 assert(_run_state == PRE_CALL_RUN ||
427 _run_state == POST_RUN, "Active Thread deleted before post_run(): "
428 "_run_state=%d", (int)_run_state);
429
430 // Notify the barrier set that a thread is being destroyed. Note that a barrier
431 // set might not be available if we encountered errors during bootstrapping.
432 BarrierSet* const barrier_set = BarrierSet::barrier_set();
433 if (barrier_set != NULL) {
434 barrier_set->on_thread_destroy(this);
435 }
436
437 // stack_base can be NULL if the thread is never started or exited before
438 // record_stack_base_and_size called. Although, we would like to ensure
439 // that all started threads do call record_stack_base_and_size(), there is
440 // not proper way to enforce that.
441 #if INCLUDE_NMT
442 if (_stack_base != NULL) {
443 MemTracker::release_thread_stack(stack_end(), stack_size());
444 #ifdef ASSERT
445 set_stack_base(NULL);
446 #endif
447 }
448 #endif // INCLUDE_NMT
449
450 // deallocate data structures
451 delete resource_area();
452 // since the handle marks are using the handle area, we have to deallocated the root
453 // handle mark before deallocating the thread's handle area,
454 assert(last_handle_mark() != NULL, "check we have an element");
455 delete last_handle_mark();
456 assert(last_handle_mark() == NULL, "check we have reached the end");
457
458 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
459 // We NULL out the fields for good hygiene.
460 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
461 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
462 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
463
464 delete handle_area();
465 delete metadata_handles();
466
467 // SR_handler uses this as a termination indicator -
468 // needs to happen before os::free_thread()
469 delete _SR_lock;
470 _SR_lock = NULL;
471
472 // osthread() can be NULL, if creation of thread failed.
473 if (osthread() != NULL) os::free_thread(osthread());
474
475 // Clear Thread::current if thread is deleting itself and it has not
476 // already been done. This must be done before the memory is deallocated.
477 // Needed to ensure JNI correctly detects non-attached threads.
478 if (this == Thread::current_or_null()) {
479 Thread::clear_thread_current();
480 }
481
482 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
483 }
484
485 #ifdef ASSERT
486 // A JavaThread is considered "dangling" if it is not the current
487 // thread, has been added the Threads list, the system is not at a
488 // safepoint and the Thread is not "protected".
489 //
490 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
491 assert(!thread->is_Java_thread() || Thread::current() == thread ||
492 !((JavaThread *) thread)->on_thread_list() ||
493 SafepointSynchronize::is_at_safepoint() ||
494 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
495 "possibility of dangling Thread pointer");
496 }
497 #endif
498
499 ThreadPriority Thread::get_priority(const Thread* const thread) {
500 ThreadPriority priority;
501 // Can return an error!
502 (void)os::get_priority(thread, priority);
503 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
504 return priority;
505 }
506
507 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
508 debug_only(check_for_dangling_thread_pointer(thread);)
509 // Can return an error!
510 (void)os::set_priority(thread, priority);
511 }
512
513
514 void Thread::start(Thread* thread) {
515 // Start is different from resume in that its safety is guaranteed by context or
516 // being called from a Java method synchronized on the Thread object.
517 if (!DisableStartThread) {
518 if (thread->is_Java_thread()) {
519 // Initialize the thread state to RUNNABLE before starting this thread.
520 // Can not set it after the thread started because we do not know the
521 // exact thread state at that time. It could be in MONITOR_WAIT or
522 // in SLEEPING or some other state.
523 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
524 java_lang_Thread::RUNNABLE);
525 }
526 os::start_thread(thread);
527 }
528 }
529
530 // Enqueue a VM_Operation to do the job for us - sometime later
531 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
532 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
533 VMThread::execute(vm_stop);
534 }
535
536
537 // Check if an external suspend request has completed (or has been
538 // cancelled). Returns true if the thread is externally suspended and
539 // false otherwise.
540 //
541 // The bits parameter returns information about the code path through
542 // the routine. Useful for debugging:
543 //
544 // set in is_ext_suspend_completed():
545 // 0x00000001 - routine was entered
546 // 0x00000010 - routine return false at end
547 // 0x00000100 - thread exited (return false)
548 // 0x00000200 - suspend request cancelled (return false)
549 // 0x00000400 - thread suspended (return true)
550 // 0x00001000 - thread is in a suspend equivalent state (return true)
551 // 0x00002000 - thread is native and walkable (return true)
552 // 0x00004000 - thread is native_trans and walkable (needed retry)
553 //
554 // set in wait_for_ext_suspend_completion():
555 // 0x00010000 - routine was entered
556 // 0x00020000 - suspend request cancelled before loop (return false)
557 // 0x00040000 - thread suspended before loop (return true)
558 // 0x00080000 - suspend request cancelled in loop (return false)
559 // 0x00100000 - thread suspended in loop (return true)
560 // 0x00200000 - suspend not completed during retry loop (return false)
561
562 // Helper class for tracing suspend wait debug bits.
563 //
564 // 0x00000100 indicates that the target thread exited before it could
565 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
566 // 0x00080000 each indicate a cancelled suspend request so they don't
567 // count as wait failures either.
568 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
569
570 class TraceSuspendDebugBits : public StackObj {
571 private:
572 JavaThread * jt;
573 bool is_wait;
574 bool called_by_wait; // meaningful when !is_wait
575 uint32_t * bits;
576
577 public:
578 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
579 uint32_t *_bits) {
580 jt = _jt;
581 is_wait = _is_wait;
582 called_by_wait = _called_by_wait;
583 bits = _bits;
584 }
585
586 ~TraceSuspendDebugBits() {
587 if (!is_wait) {
588 #if 1
589 // By default, don't trace bits for is_ext_suspend_completed() calls.
590 // That trace is very chatty.
591 return;
592 #else
593 if (!called_by_wait) {
594 // If tracing for is_ext_suspend_completed() is enabled, then only
595 // trace calls to it from wait_for_ext_suspend_completion()
596 return;
597 }
598 #endif
599 }
600
601 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
602 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
603 MutexLocker ml(Threads_lock); // needed for get_thread_name()
604 ResourceMark rm;
605
606 tty->print_cr(
607 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
608 jt->get_thread_name(), *bits);
609
610 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
611 }
612 }
613 }
614 };
615 #undef DEBUG_FALSE_BITS
616
617
618 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
619 uint32_t *bits) {
620 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
621
622 bool did_trans_retry = false; // only do thread_in_native_trans retry once
623 bool do_trans_retry; // flag to force the retry
624
625 *bits |= 0x00000001;
626
627 do {
628 do_trans_retry = false;
629
630 if (is_exiting()) {
631 // Thread is in the process of exiting. This is always checked
632 // first to reduce the risk of dereferencing a freed JavaThread.
633 *bits |= 0x00000100;
634 return false;
635 }
636
637 if (!is_external_suspend()) {
638 // Suspend request is cancelled. This is always checked before
639 // is_ext_suspended() to reduce the risk of a rogue resume
640 // confusing the thread that made the suspend request.
641 *bits |= 0x00000200;
642 return false;
643 }
644
645 if (is_ext_suspended()) {
646 // thread is suspended
647 *bits |= 0x00000400;
648 return true;
649 }
650
651 // Now that we no longer do hard suspends of threads running
652 // native code, the target thread can be changing thread state
653 // while we are in this routine:
654 //
655 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
656 //
657 // We save a copy of the thread state as observed at this moment
658 // and make our decision about suspend completeness based on the
659 // copy. This closes the race where the thread state is seen as
660 // _thread_in_native_trans in the if-thread_blocked check, but is
661 // seen as _thread_blocked in if-thread_in_native_trans check.
662 JavaThreadState save_state = thread_state();
663
664 if (save_state == _thread_blocked && is_suspend_equivalent()) {
665 // If the thread's state is _thread_blocked and this blocking
666 // condition is known to be equivalent to a suspend, then we can
667 // consider the thread to be externally suspended. This means that
668 // the code that sets _thread_blocked has been modified to do
669 // self-suspension if the blocking condition releases. We also
670 // used to check for CONDVAR_WAIT here, but that is now covered by
671 // the _thread_blocked with self-suspension check.
672 //
673 // Return true since we wouldn't be here unless there was still an
674 // external suspend request.
675 *bits |= 0x00001000;
676 return true;
677 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
678 // Threads running native code will self-suspend on native==>VM/Java
679 // transitions. If its stack is walkable (should always be the case
680 // unless this function is called before the actual java_suspend()
681 // call), then the wait is done.
682 *bits |= 0x00002000;
683 return true;
684 } else if (!called_by_wait && !did_trans_retry &&
685 save_state == _thread_in_native_trans &&
686 frame_anchor()->walkable()) {
687 // The thread is transitioning from thread_in_native to another
688 // thread state. check_safepoint_and_suspend_for_native_trans()
689 // will force the thread to self-suspend. If it hasn't gotten
690 // there yet we may have caught the thread in-between the native
691 // code check above and the self-suspend. Lucky us. If we were
692 // called by wait_for_ext_suspend_completion(), then it
693 // will be doing the retries so we don't have to.
694 //
695 // Since we use the saved thread state in the if-statement above,
696 // there is a chance that the thread has already transitioned to
697 // _thread_blocked by the time we get here. In that case, we will
698 // make a single unnecessary pass through the logic below. This
699 // doesn't hurt anything since we still do the trans retry.
700
701 *bits |= 0x00004000;
702
703 // Once the thread leaves thread_in_native_trans for another
704 // thread state, we break out of this retry loop. We shouldn't
705 // need this flag to prevent us from getting back here, but
706 // sometimes paranoia is good.
707 did_trans_retry = true;
708
709 // We wait for the thread to transition to a more usable state.
710 for (int i = 1; i <= SuspendRetryCount; i++) {
711 // We used to do an "os::yield_all(i)" call here with the intention
712 // that yielding would increase on each retry. However, the parameter
713 // is ignored on Linux which means the yield didn't scale up. Waiting
714 // on the SR_lock below provides a much more predictable scale up for
715 // the delay. It also provides a simple/direct point to check for any
716 // safepoint requests from the VMThread
717
718 // temporarily drops SR_lock while doing wait with safepoint check
719 // (if we're a JavaThread - the WatcherThread can also call this)
720 // and increase delay with each retry
721 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
722
723 // check the actual thread state instead of what we saved above
724 if (thread_state() != _thread_in_native_trans) {
725 // the thread has transitioned to another thread state so
726 // try all the checks (except this one) one more time.
727 do_trans_retry = true;
728 break;
729 }
730 } // end retry loop
731
732
733 }
734 } while (do_trans_retry);
735
736 *bits |= 0x00000010;
737 return false;
738 }
739
740 // Wait for an external suspend request to complete (or be cancelled).
741 // Returns true if the thread is externally suspended and false otherwise.
742 //
743 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
744 uint32_t *bits) {
745 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
746 false /* !called_by_wait */, bits);
747
748 // local flag copies to minimize SR_lock hold time
749 bool is_suspended;
750 bool pending;
751 uint32_t reset_bits;
752
753 // set a marker so is_ext_suspend_completed() knows we are the caller
754 *bits |= 0x00010000;
755
756 // We use reset_bits to reinitialize the bits value at the top of
757 // each retry loop. This allows the caller to make use of any
758 // unused bits for their own marking purposes.
759 reset_bits = *bits;
760
761 {
762 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
763 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
764 delay, bits);
765 pending = is_external_suspend();
766 }
767 // must release SR_lock to allow suspension to complete
768
769 if (!pending) {
770 // A cancelled suspend request is the only false return from
771 // is_ext_suspend_completed() that keeps us from entering the
772 // retry loop.
773 *bits |= 0x00020000;
774 return false;
775 }
776
777 if (is_suspended) {
778 *bits |= 0x00040000;
779 return true;
780 }
781
782 for (int i = 1; i <= retries; i++) {
783 *bits = reset_bits; // reinit to only track last retry
784
785 // We used to do an "os::yield_all(i)" call here with the intention
786 // that yielding would increase on each retry. However, the parameter
787 // is ignored on Linux which means the yield didn't scale up. Waiting
788 // on the SR_lock below provides a much more predictable scale up for
789 // the delay. It also provides a simple/direct point to check for any
790 // safepoint requests from the VMThread
791
792 {
793 MutexLocker ml(SR_lock());
794 // wait with safepoint check (if we're a JavaThread - the WatcherThread
795 // can also call this) and increase delay with each retry
796 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
797
798 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
799 delay, bits);
800
801 // It is possible for the external suspend request to be cancelled
802 // (by a resume) before the actual suspend operation is completed.
803 // Refresh our local copy to see if we still need to wait.
804 pending = is_external_suspend();
805 }
806
807 if (!pending) {
808 // A cancelled suspend request is the only false return from
809 // is_ext_suspend_completed() that keeps us from staying in the
810 // retry loop.
811 *bits |= 0x00080000;
812 return false;
813 }
814
815 if (is_suspended) {
816 *bits |= 0x00100000;
817 return true;
818 }
819 } // end retry loop
820
821 // thread did not suspend after all our retries
822 *bits |= 0x00200000;
823 return false;
824 }
825
826 // Called from API entry points which perform stack walking. If the
827 // associated JavaThread is the current thread, then wait_for_suspend
828 // is not used. Otherwise, it determines if we should wait for the
829 // "other" thread to complete external suspension. (NOTE: in future
830 // releases the suspension mechanism should be reimplemented so this
831 // is not necessary.)
832 //
833 bool
834 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
835 if (this != JavaThread::current()) {
836 // "other" threads require special handling.
837 if (wait_for_suspend) {
838 // We are allowed to wait for the external suspend to complete
839 // so give the other thread a chance to get suspended.
840 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
841 SuspendRetryDelay, bits)) {
842 // Didn't make it so let the caller know.
843 return false;
844 }
845 }
846 // We aren't allowed to wait for the external suspend to complete
847 // so if the other thread isn't externally suspended we need to
848 // let the caller know.
849 else if (!is_ext_suspend_completed_with_lock(bits)) {
850 return false;
851 }
852 }
853
854 return true;
855 }
856
857 #ifndef PRODUCT
858 void JavaThread::record_jump(address target, address instr, const char* file,
859 int line) {
860
861 // This should not need to be atomic as the only way for simultaneous
862 // updates is via interrupts. Even then this should be rare or non-existent
863 // and we don't care that much anyway.
864
865 int index = _jmp_ring_index;
866 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
867 _jmp_ring[index]._target = (intptr_t) target;
868 _jmp_ring[index]._instruction = (intptr_t) instr;
869 _jmp_ring[index]._file = file;
870 _jmp_ring[index]._line = line;
871 }
872 #endif // PRODUCT
873
874 void Thread::interrupt(Thread* thread) {
875 debug_only(check_for_dangling_thread_pointer(thread);)
876 os::interrupt(thread);
877 }
878
879 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
880 debug_only(check_for_dangling_thread_pointer(thread);)
881 // Note: If clear_interrupted==false, this simply fetches and
882 // returns the value of the field osthread()->interrupted().
883 return os::is_interrupted(thread, clear_interrupted);
884 }
885
886
887 // GC Support
888 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
889 int thread_parity = _oops_do_parity;
890 if (thread_parity != strong_roots_parity) {
891 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
892 if (res == thread_parity) {
893 return true;
894 } else {
895 guarantee(res == strong_roots_parity, "Or else what?");
896 return false;
897 }
898 }
899 return false;
900 }
901
902 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
903 active_handles()->oops_do(f);
904 // Do oop for ThreadShadow
905 f->do_oop((oop*)&_pending_exception);
906 handle_area()->oops_do(f);
907
908 // We scan thread local monitor lists here, and the remaining global
909 // monitors in ObjectSynchronizer::oops_do().
910 ObjectSynchronizer::thread_local_used_oops_do(this, f);
911 }
912
913 void Thread::metadata_handles_do(void f(Metadata*)) {
914 // Only walk the Handles in Thread.
915 if (metadata_handles() != NULL) {
916 for (int i = 0; i< metadata_handles()->length(); i++) {
917 f(metadata_handles()->at(i));
918 }
919 }
920 }
921
922 void Thread::print_on(outputStream* st, bool print_extended_info) const {
923 // get_priority assumes osthread initialized
924 if (osthread() != NULL) {
925 int os_prio;
926 if (os::get_native_priority(this, &os_prio) == OS_OK) {
927 st->print("os_prio=%d ", os_prio);
928 }
929
930 st->print("cpu=%.2fms ",
931 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
932 );
933 st->print("elapsed=%.2fs ",
934 _statistical_info.getElapsedTime() / 1000.0
935 );
936 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
937 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
938 st->print("allocated=" SIZE_FORMAT "%s ",
939 byte_size_in_proper_unit(allocated_bytes),
940 proper_unit_for_byte_size(allocated_bytes)
941 );
942 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
943 }
944
945 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
946 osthread()->print_on(st);
947 }
948 ThreadsSMRSupport::print_info_on(this, st);
949 st->print(" ");
950 debug_only(if (WizardMode) print_owned_locks_on(st);)
951 }
952
953 // Thread::print_on_error() is called by fatal error handler. Don't use
954 // any lock or allocate memory.
955 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
956 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
957
958 if (is_VM_thread()) { st->print("VMThread"); }
959 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
960 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
961 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
962 else { st->print("Thread"); }
963
964 if (is_Named_thread()) {
965 st->print(" \"%s\"", name());
966 }
967
968 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
969 p2i(stack_end()), p2i(stack_base()));
970
971 if (osthread()) {
972 st->print(" [id=%d]", osthread()->thread_id());
973 }
974
975 ThreadsSMRSupport::print_info_on(this, st);
976 }
977
978 void Thread::print_value_on(outputStream* st) const {
979 if (is_Named_thread()) {
980 st->print(" \"%s\" ", name());
981 }
982 st->print(INTPTR_FORMAT, p2i(this)); // print address
983 }
984
985 #ifdef ASSERT
986 void Thread::print_owned_locks_on(outputStream* st) const {
987 Monitor *cur = _owned_locks;
988 if (cur == NULL) {
989 st->print(" (no locks) ");
990 } else {
991 st->print_cr(" Locks owned:");
992 while (cur) {
993 cur->print_on(st);
994 cur = cur->next();
995 }
996 }
997 }
998
999 static int ref_use_count = 0;
1000
1001 bool Thread::owns_locks_but_compiled_lock() const {
1002 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1003 if (cur != Compile_lock) return true;
1004 }
1005 return false;
1006 }
1007
1008
1009 #endif
1010
1011 #ifndef PRODUCT
1012
1013 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
1014 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
1015 // no locks which allow_vm_block's are held
1016 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
1017 // Check if current thread is allowed to block at a safepoint
1018 if (!(_allow_safepoint_count == 0)) {
1019 fatal("Possible safepoint reached by thread that does not allow it");
1020 }
1021 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
1022 fatal("LEAF method calling lock?");
1023 }
1024
1025 #ifdef ASSERT
1026 if (potential_vm_operation && is_Java_thread()
1027 && !Universe::is_bootstrapping()) {
1028 // Make sure we do not hold any locks that the VM thread also uses.
1029 // This could potentially lead to deadlocks
1030 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1031 // Threads_lock is special, since the safepoint synchronization will not start before this is
1032 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
1033 // since it is used to transfer control between JavaThreads and the VMThread
1034 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
1035 if ((cur->allow_vm_block() &&
1036 cur != Threads_lock &&
1037 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
1038 cur != VMOperationRequest_lock &&
1039 cur != VMOperationQueue_lock) ||
1040 cur->rank() == Mutex::special) {
1041 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
1042 }
1043 }
1044 }
1045
1046 if (GCALotAtAllSafepoints) {
1047 // We could enter a safepoint here and thus have a gc
1048 InterfaceSupport::check_gc_alot();
1049 }
1050 #endif
1051 }
1052 #endif
1053
1054 bool Thread::is_in_stack(address adr) const {
1055 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1056 address end = os::current_stack_pointer();
1057 // Allow non Java threads to call this without stack_base
1058 if (_stack_base == NULL) return true;
1059 if (stack_base() >= adr && adr >= end) return true;
1060
1061 return false;
1062 }
1063
1064 bool Thread::is_in_usable_stack(address adr) const {
1065 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1066 size_t usable_stack_size = _stack_size - stack_guard_size;
1067
1068 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1069 }
1070
1071
1072 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1073 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1074 // used for compilation in the future. If that change is made, the need for these methods
1075 // should be revisited, and they should be removed if possible.
1076
1077 bool Thread::is_lock_owned(address adr) const {
1078 return on_local_stack(adr);
1079 }
1080
1081 bool Thread::set_as_starting_thread() {
1082 assert(_starting_thread == NULL, "already initialized: "
1083 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
1084 // NOTE: this must be called inside the main thread.
1085 DEBUG_ONLY(_starting_thread = this;)
1086 return os::create_main_thread((JavaThread*)this);
1087 }
1088
1089 static void initialize_class(Symbol* class_name, TRAPS) {
1090 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1091 InstanceKlass::cast(klass)->initialize(CHECK);
1092 }
1093
1094
1095 // Creates the initial ThreadGroup
1096 static Handle create_initial_thread_group(TRAPS) {
1097 Handle system_instance = JavaCalls::construct_new_instance(
1098 SystemDictionary::ThreadGroup_klass(),
1099 vmSymbols::void_method_signature(),
1100 CHECK_NH);
1101 Universe::set_system_thread_group(system_instance());
1102
1103 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1104 Handle main_instance = JavaCalls::construct_new_instance(
1105 SystemDictionary::ThreadGroup_klass(),
1106 vmSymbols::threadgroup_string_void_signature(),
1107 system_instance,
1108 string,
1109 CHECK_NH);
1110 return main_instance;
1111 }
1112
1113 // Creates the initial Thread
1114 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1115 TRAPS) {
1116 InstanceKlass* ik = SystemDictionary::Thread_klass();
1117 assert(ik->is_initialized(), "must be");
1118 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1119
1120 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1121 // constructor calls Thread.current(), which must be set here for the
1122 // initial thread.
1123 java_lang_Thread::set_thread(thread_oop(), thread);
1124 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1125 thread->set_threadObj(thread_oop());
1126
1127 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1128
1129 JavaValue result(T_VOID);
1130 JavaCalls::call_special(&result, thread_oop,
1131 ik,
1132 vmSymbols::object_initializer_name(),
1133 vmSymbols::threadgroup_string_void_signature(),
1134 thread_group,
1135 string,
1136 CHECK_NULL);
1137 return thread_oop();
1138 }
1139
1140 char java_runtime_name[128] = "";
1141 char java_runtime_version[128] = "";
1142
1143 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1144 static const char* get_java_runtime_name(TRAPS) {
1145 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1146 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1147 fieldDescriptor fd;
1148 bool found = k != NULL &&
1149 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1150 vmSymbols::string_signature(), &fd);
1151 if (found) {
1152 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1153 if (name_oop == NULL) {
1154 return NULL;
1155 }
1156 const char* name = java_lang_String::as_utf8_string(name_oop,
1157 java_runtime_name,
1158 sizeof(java_runtime_name));
1159 return name;
1160 } else {
1161 return NULL;
1162 }
1163 }
1164
1165 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1166 static const char* get_java_runtime_version(TRAPS) {
1167 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1168 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1169 fieldDescriptor fd;
1170 bool found = k != NULL &&
1171 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1172 vmSymbols::string_signature(), &fd);
1173 if (found) {
1174 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1175 if (name_oop == NULL) {
1176 return NULL;
1177 }
1178 const char* name = java_lang_String::as_utf8_string(name_oop,
1179 java_runtime_version,
1180 sizeof(java_runtime_version));
1181 return name;
1182 } else {
1183 return NULL;
1184 }
1185 }
1186
1187 // General purpose hook into Java code, run once when the VM is initialized.
1188 // The Java library method itself may be changed independently from the VM.
1189 static void call_postVMInitHook(TRAPS) {
1190 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1191 if (klass != NULL) {
1192 JavaValue result(T_VOID);
1193 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1194 vmSymbols::void_method_signature(),
1195 CHECK);
1196 }
1197 }
1198
1199 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1200 bool daemon, TRAPS) {
1201 assert(thread_group.not_null(), "thread group should be specified");
1202 assert(threadObj() == NULL, "should only create Java thread object once");
1203
1204 InstanceKlass* ik = SystemDictionary::Thread_klass();
1205 assert(ik->is_initialized(), "must be");
1206 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1207
1208 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1209 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1210 // constructor calls Thread.current(), which must be set here.
1211 java_lang_Thread::set_thread(thread_oop(), this);
1212 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1213 set_threadObj(thread_oop());
1214
1215 JavaValue result(T_VOID);
1216 if (thread_name != NULL) {
1217 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1218 // Thread gets assigned specified name and null target
1219 JavaCalls::call_special(&result,
1220 thread_oop,
1221 ik,
1222 vmSymbols::object_initializer_name(),
1223 vmSymbols::threadgroup_string_void_signature(),
1224 thread_group,
1225 name,
1226 THREAD);
1227 } else {
1228 // Thread gets assigned name "Thread-nnn" and null target
1229 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1230 JavaCalls::call_special(&result,
1231 thread_oop,
1232 ik,
1233 vmSymbols::object_initializer_name(),
1234 vmSymbols::threadgroup_runnable_void_signature(),
1235 thread_group,
1236 Handle(),
1237 THREAD);
1238 }
1239
1240
1241 if (daemon) {
1242 java_lang_Thread::set_daemon(thread_oop());
1243 }
1244
1245 if (HAS_PENDING_EXCEPTION) {
1246 return;
1247 }
1248
1249 Klass* group = SystemDictionary::ThreadGroup_klass();
1250 Handle threadObj(THREAD, this->threadObj());
1251
1252 JavaCalls::call_special(&result,
1253 thread_group,
1254 group,
1255 vmSymbols::add_method_name(),
1256 vmSymbols::thread_void_signature(),
1257 threadObj, // Arg 1
1258 THREAD);
1259 }
1260
1261 // List of all NonJavaThreads and safe iteration over that list.
1262
1263 class NonJavaThread::List {
1264 public:
1265 NonJavaThread* volatile _head;
1266 SingleWriterSynchronizer _protect;
1267
1268 List() : _head(NULL), _protect() {}
1269 };
1270
1271 NonJavaThread::List NonJavaThread::_the_list;
1272
1273 NonJavaThread::Iterator::Iterator() :
1274 _protect_enter(_the_list._protect.enter()),
1275 _current(OrderAccess::load_acquire(&_the_list._head))
1276 {}
1277
1278 NonJavaThread::Iterator::~Iterator() {
1279 _the_list._protect.exit(_protect_enter);
1280 }
1281
1282 void NonJavaThread::Iterator::step() {
1283 assert(!end(), "precondition");
1284 _current = OrderAccess::load_acquire(&_current->_next);
1285 }
1286
1287 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) {
1288 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!");
1289 }
1290
1291 NonJavaThread::~NonJavaThread() { }
1292
1293 void NonJavaThread::add_to_the_list() {
1294 MutexLockerEx lock(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1295 _next = _the_list._head;
1296 OrderAccess::release_store(&_the_list._head, this);
1297 }
1298
1299 void NonJavaThread::remove_from_the_list() {
1300 MutexLockerEx lock(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1301 NonJavaThread* volatile* p = &_the_list._head;
1302 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) {
1303 if (t == this) {
1304 *p = this->_next;
1305 // Wait for any in-progress iterators. Concurrent synchronize is
1306 // not allowed, so do it while holding the list lock.
1307 _the_list._protect.synchronize();
1308 break;
1309 }
1310 }
1311 }
1312
1313 void NonJavaThread::pre_run() {
1314 {
1315 BarrierSet* bs = BarrierSet::barrier_set();
1316 assert(BarrierSet::barrier_set() != NULL, "invariant");
1317 SuspendibleThreadSetJoiner sts(bs->needs_sts_sync_on_attach_detach() &&
1318 !is_VM_thread() && !is_Worker_thread());
1319 add_to_the_list();
1320
1321 // Initialize BarrierSet-related data after adding to list.
1322 bs->on_thread_attach(this);
1323 }
1324
1325 // This is slightly odd in that NamedThread is a subclass, but
1326 // in fact name() is defined in Thread
1327 assert(this->name() != NULL, "thread name was not set before it was started");
1328 this->set_native_thread_name(this->name());
1329 }
1330
1331 void NonJavaThread::post_run() {
1332 JFR_ONLY(Jfr::on_thread_exit(this);)
1333 {
1334 BarrierSet* bs = BarrierSet::barrier_set();
1335 SuspendibleThreadSetJoiner sts(bs->needs_sts_sync_on_attach_detach() &&
1336 !is_VM_thread() && !is_Worker_thread());
1337
1338 // Clean up BarrierSet data before removing from list.
1339 bs->on_thread_detach(this);
1340
1341 remove_from_the_list();
1342 }
1343 // Ensure thread-local-storage is cleared before termination.
1344 Thread::clear_thread_current();
1345 }
1346
1347 // NamedThread -- non-JavaThread subclasses with multiple
1348 // uniquely named instances should derive from this.
1349 NamedThread::NamedThread() :
1350 NonJavaThread(),
1351 _name(NULL),
1352 _processed_thread(NULL),
1353 _gc_id(GCId::undefined())
1354 {}
1355
1356 NamedThread::~NamedThread() {
1357 if (_name != NULL) {
1358 FREE_C_HEAP_ARRAY(char, _name);
1359 _name = NULL;
1360 }
1361 }
1362
1363 void NamedThread::set_name(const char* format, ...) {
1364 guarantee(_name == NULL, "Only get to set name once.");
1365 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1366 guarantee(_name != NULL, "alloc failure");
1367 va_list ap;
1368 va_start(ap, format);
1369 jio_vsnprintf(_name, max_name_len, format, ap);
1370 va_end(ap);
1371 }
1372
1373 void NamedThread::print_on(outputStream* st) const {
1374 st->print("\"%s\" ", name());
1375 Thread::print_on(st);
1376 st->cr();
1377 }
1378
1379
1380 // ======= WatcherThread ========
1381
1382 // The watcher thread exists to simulate timer interrupts. It should
1383 // be replaced by an abstraction over whatever native support for
1384 // timer interrupts exists on the platform.
1385
1386 WatcherThread* WatcherThread::_watcher_thread = NULL;
1387 bool WatcherThread::_startable = false;
1388 volatile bool WatcherThread::_should_terminate = false;
1389
1390 WatcherThread::WatcherThread() : NonJavaThread() {
1391 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1392 if (os::create_thread(this, os::watcher_thread)) {
1393 _watcher_thread = this;
1394
1395 // Set the watcher thread to the highest OS priority which should not be
1396 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1397 // is created. The only normal thread using this priority is the reference
1398 // handler thread, which runs for very short intervals only.
1399 // If the VMThread's priority is not lower than the WatcherThread profiling
1400 // will be inaccurate.
1401 os::set_priority(this, MaxPriority);
1402 if (!DisableStartThread) {
1403 os::start_thread(this);
1404 }
1405 }
1406 }
1407
1408 int WatcherThread::sleep() const {
1409 // The WatcherThread does not participate in the safepoint protocol
1410 // for the PeriodicTask_lock because it is not a JavaThread.
1411 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1412
1413 if (_should_terminate) {
1414 // check for termination before we do any housekeeping or wait
1415 return 0; // we did not sleep.
1416 }
1417
1418 // remaining will be zero if there are no tasks,
1419 // causing the WatcherThread to sleep until a task is
1420 // enrolled
1421 int remaining = PeriodicTask::time_to_wait();
1422 int time_slept = 0;
1423
1424 // we expect this to timeout - we only ever get unparked when
1425 // we should terminate or when a new task has been enrolled
1426 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1427
1428 jlong time_before_loop = os::javaTimeNanos();
1429
1430 while (true) {
1431 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1432 remaining);
1433 jlong now = os::javaTimeNanos();
1434
1435 if (remaining == 0) {
1436 // if we didn't have any tasks we could have waited for a long time
1437 // consider the time_slept zero and reset time_before_loop
1438 time_slept = 0;
1439 time_before_loop = now;
1440 } else {
1441 // need to recalculate since we might have new tasks in _tasks
1442 time_slept = (int) ((now - time_before_loop) / 1000000);
1443 }
1444
1445 // Change to task list or spurious wakeup of some kind
1446 if (timedout || _should_terminate) {
1447 break;
1448 }
1449
1450 remaining = PeriodicTask::time_to_wait();
1451 if (remaining == 0) {
1452 // Last task was just disenrolled so loop around and wait until
1453 // another task gets enrolled
1454 continue;
1455 }
1456
1457 remaining -= time_slept;
1458 if (remaining <= 0) {
1459 break;
1460 }
1461 }
1462
1463 return time_slept;
1464 }
1465
1466 void WatcherThread::run() {
1467 assert(this == watcher_thread(), "just checking");
1468
1469 this->set_active_handles(JNIHandleBlock::allocate_block());
1470 while (true) {
1471 assert(watcher_thread() == Thread::current(), "thread consistency check");
1472 assert(watcher_thread() == this, "thread consistency check");
1473
1474 // Calculate how long it'll be until the next PeriodicTask work
1475 // should be done, and sleep that amount of time.
1476 int time_waited = sleep();
1477
1478 if (VMError::is_error_reported()) {
1479 // A fatal error has happened, the error handler(VMError::report_and_die)
1480 // should abort JVM after creating an error log file. However in some
1481 // rare cases, the error handler itself might deadlock. Here periodically
1482 // check for error reporting timeouts, and if it happens, just proceed to
1483 // abort the VM.
1484
1485 // This code is in WatcherThread because WatcherThread wakes up
1486 // periodically so the fatal error handler doesn't need to do anything;
1487 // also because the WatcherThread is less likely to crash than other
1488 // threads.
1489
1490 for (;;) {
1491 // Note: we use naked sleep in this loop because we want to avoid using
1492 // any kind of VM infrastructure which may be broken at this point.
1493 if (VMError::check_timeout()) {
1494 // We hit error reporting timeout. Error reporting was interrupted and
1495 // will be wrapping things up now (closing files etc). Give it some more
1496 // time, then quit the VM.
1497 os::naked_short_sleep(200);
1498 // Print a message to stderr.
1499 fdStream err(defaultStream::output_fd());
1500 err.print_raw_cr("# [ timer expired, abort... ]");
1501 // skip atexit/vm_exit/vm_abort hooks
1502 os::die();
1503 }
1504
1505 // Wait a second, then recheck for timeout.
1506 os::naked_short_sleep(999);
1507 }
1508 }
1509
1510 if (_should_terminate) {
1511 // check for termination before posting the next tick
1512 break;
1513 }
1514
1515 PeriodicTask::real_time_tick(time_waited);
1516 }
1517
1518 // Signal that it is terminated
1519 {
1520 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1521 _watcher_thread = NULL;
1522 Terminator_lock->notify();
1523 }
1524 }
1525
1526 void WatcherThread::start() {
1527 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1528
1529 if (watcher_thread() == NULL && _startable) {
1530 _should_terminate = false;
1531 // Create the single instance of WatcherThread
1532 new WatcherThread();
1533 }
1534 }
1535
1536 void WatcherThread::make_startable() {
1537 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1538 _startable = true;
1539 }
1540
1541 void WatcherThread::stop() {
1542 {
1543 // Follow normal safepoint aware lock enter protocol since the
1544 // WatcherThread is stopped by another JavaThread.
1545 MutexLocker ml(PeriodicTask_lock);
1546 _should_terminate = true;
1547
1548 WatcherThread* watcher = watcher_thread();
1549 if (watcher != NULL) {
1550 // unpark the WatcherThread so it can see that it should terminate
1551 watcher->unpark();
1552 }
1553 }
1554
1555 MutexLocker mu(Terminator_lock);
1556
1557 while (watcher_thread() != NULL) {
1558 // This wait should make safepoint checks, wait without a timeout,
1559 // and wait as a suspend-equivalent condition.
1560 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1561 Mutex::_as_suspend_equivalent_flag);
1562 }
1563 }
1564
1565 void WatcherThread::unpark() {
1566 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1567 PeriodicTask_lock->notify();
1568 }
1569
1570 void WatcherThread::print_on(outputStream* st) const {
1571 st->print("\"%s\" ", name());
1572 Thread::print_on(st);
1573 st->cr();
1574 }
1575
1576 // ======= JavaThread ========
1577
1578 #if INCLUDE_JVMCI
1579
1580 jlong* JavaThread::_jvmci_old_thread_counters;
1581
1582 bool jvmci_counters_include(JavaThread* thread) {
1583 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1584 }
1585
1586 void JavaThread::collect_counters(typeArrayOop array) {
1587 if (JVMCICounterSize > 0) {
1588 JavaThreadIteratorWithHandle jtiwh;
1589 for (int i = 0; i < array->length(); i++) {
1590 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1591 }
1592 for (; JavaThread *tp = jtiwh.next(); ) {
1593 if (jvmci_counters_include(tp)) {
1594 for (int i = 0; i < array->length(); i++) {
1595 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1596 }
1597 }
1598 }
1599 }
1600 }
1601
1602 #endif // INCLUDE_JVMCI
1603
1604 // A JavaThread is a normal Java thread
1605
1606 void JavaThread::initialize() {
1607 // Initialize fields
1608
1609 set_saved_exception_pc(NULL);
1610 set_threadObj(NULL);
1611 _anchor.clear();
1612 set_entry_point(NULL);
1613 set_jni_functions(jni_functions());
1614 set_callee_target(NULL);
1615 set_vm_result(NULL);
1616 set_vm_result_2(NULL);
1617 set_vframe_array_head(NULL);
1618 set_vframe_array_last(NULL);
1619 set_deferred_locals(NULL);
1620 set_deopt_mark(NULL);
1621 set_deopt_compiled_method(NULL);
1622 clear_must_deopt_id();
1623 set_monitor_chunks(NULL);
1624 set_next(NULL);
1625 _on_thread_list = false;
1626 set_thread_state(_thread_new);
1627 _terminated = _not_terminated;
1628 _array_for_gc = NULL;
1629 _suspend_equivalent = false;
1630 _in_deopt_handler = 0;
1631 _doing_unsafe_access = false;
1632 _stack_guard_state = stack_guard_unused;
1633 #if INCLUDE_JVMCI
1634 _pending_monitorenter = false;
1635 _pending_deoptimization = -1;
1636 _pending_failed_speculation = 0;
1637 _pending_transfer_to_interpreter = false;
1638 _adjusting_comp_level = false;
1639 _in_retryable_allocation = false;
1640 _jvmci._alternate_call_target = NULL;
1641 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1642 if (JVMCICounterSize > 0) {
1643 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1644 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1645 } else {
1646 _jvmci_counters = NULL;
1647 }
1648 #endif // INCLUDE_JVMCI
1649 _reserved_stack_activation = NULL; // stack base not known yet
1650 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1651 _exception_pc = 0;
1652 _exception_handler_pc = 0;
1653 _is_method_handle_return = 0;
1654 _jvmti_thread_state= NULL;
1655 _should_post_on_exceptions_flag = JNI_FALSE;
1656 _interp_only_mode = 0;
1657 _special_runtime_exit_condition = _no_async_condition;
1658 _pending_async_exception = NULL;
1659 _thread_stat = NULL;
1660 _thread_stat = new ThreadStatistics();
1661 _blocked_on_compilation = false;
1662 _jni_active_critical = 0;
1663 _pending_jni_exception_check_fn = NULL;
1664 _do_not_unlock_if_synchronized = false;
1665 _cached_monitor_info = NULL;
1666 _parker = Parker::Allocate(this);
1667
1668 #ifndef PRODUCT
1669 _jmp_ring_index = 0;
1670 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1671 record_jump(NULL, NULL, NULL, 0);
1672 }
1673 #endif // PRODUCT
1674
1675 // Setup safepoint state info for this thread
1676 ThreadSafepointState::create(this);
1677
1678 debug_only(_java_call_counter = 0);
1679
1680 // JVMTI PopFrame support
1681 _popframe_condition = popframe_inactive;
1682 _popframe_preserved_args = NULL;
1683 _popframe_preserved_args_size = 0;
1684 _frames_to_pop_failed_realloc = 0;
1685
1686 if (SafepointMechanism::uses_thread_local_poll()) {
1687 SafepointMechanism::initialize_header(this);
1688 }
1689
1690 _class_to_be_initialized = NULL;
1691
1692 pd_initialize();
1693 }
1694
1695 JavaThread::JavaThread(bool is_attaching_via_jni) :
1696 Thread() {
1697 initialize();
1698 if (is_attaching_via_jni) {
1699 _jni_attach_state = _attaching_via_jni;
1700 } else {
1701 _jni_attach_state = _not_attaching_via_jni;
1702 }
1703 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1704 }
1705
1706 bool JavaThread::reguard_stack(address cur_sp) {
1707 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1708 && _stack_guard_state != stack_guard_reserved_disabled) {
1709 return true; // Stack already guarded or guard pages not needed.
1710 }
1711
1712 if (register_stack_overflow()) {
1713 // For those architectures which have separate register and
1714 // memory stacks, we must check the register stack to see if
1715 // it has overflowed.
1716 return false;
1717 }
1718
1719 // Java code never executes within the yellow zone: the latter is only
1720 // there to provoke an exception during stack banging. If java code
1721 // is executing there, either StackShadowPages should be larger, or
1722 // some exception code in c1, c2 or the interpreter isn't unwinding
1723 // when it should.
1724 guarantee(cur_sp > stack_reserved_zone_base(),
1725 "not enough space to reguard - increase StackShadowPages");
1726 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1727 enable_stack_yellow_reserved_zone();
1728 if (reserved_stack_activation() != stack_base()) {
1729 set_reserved_stack_activation(stack_base());
1730 }
1731 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1732 set_reserved_stack_activation(stack_base());
1733 enable_stack_reserved_zone();
1734 }
1735 return true;
1736 }
1737
1738 bool JavaThread::reguard_stack(void) {
1739 return reguard_stack(os::current_stack_pointer());
1740 }
1741
1742
1743 void JavaThread::block_if_vm_exited() {
1744 if (_terminated == _vm_exited) {
1745 // _vm_exited is set at safepoint, and Threads_lock is never released
1746 // we will block here forever
1747 Threads_lock->lock_without_safepoint_check();
1748 ShouldNotReachHere();
1749 }
1750 }
1751
1752
1753 // Remove this ifdef when C1 is ported to the compiler interface.
1754 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1755 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1756
1757 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1758 Thread() {
1759 initialize();
1760 _jni_attach_state = _not_attaching_via_jni;
1761 set_entry_point(entry_point);
1762 // Create the native thread itself.
1763 // %note runtime_23
1764 os::ThreadType thr_type = os::java_thread;
1765 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1766 os::java_thread;
1767 os::create_thread(this, thr_type, stack_sz);
1768 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1769 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1770 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1771 // the exception consists of creating the exception object & initializing it, initialization
1772 // will leave the VM via a JavaCall and then all locks must be unlocked).
1773 //
1774 // The thread is still suspended when we reach here. Thread must be explicit started
1775 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1776 // by calling Threads:add. The reason why this is not done here, is because the thread
1777 // object must be fully initialized (take a look at JVM_Start)
1778 }
1779
1780 JavaThread::~JavaThread() {
1781
1782 // JSR166 -- return the parker to the free list
1783 Parker::Release(_parker);
1784 _parker = NULL;
1785
1786 // Free any remaining previous UnrollBlock
1787 vframeArray* old_array = vframe_array_last();
1788
1789 if (old_array != NULL) {
1790 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1791 old_array->set_unroll_block(NULL);
1792 delete old_info;
1793 delete old_array;
1794 }
1795
1796 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1797 if (deferred != NULL) {
1798 // This can only happen if thread is destroyed before deoptimization occurs.
1799 assert(deferred->length() != 0, "empty array!");
1800 do {
1801 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1802 deferred->remove_at(0);
1803 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1804 delete dlv;
1805 } while (deferred->length() != 0);
1806 delete deferred;
1807 }
1808
1809 // All Java related clean up happens in exit
1810 ThreadSafepointState::destroy(this);
1811 if (_thread_stat != NULL) delete _thread_stat;
1812
1813 #if INCLUDE_JVMCI
1814 if (JVMCICounterSize > 0) {
1815 if (jvmci_counters_include(this)) {
1816 for (int i = 0; i < JVMCICounterSize; i++) {
1817 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1818 }
1819 }
1820 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1821 }
1822 #endif // INCLUDE_JVMCI
1823 }
1824
1825
1826 // First JavaThread specific code executed by a new Java thread.
1827 void JavaThread::pre_run() {
1828 // empty - see comments in run()
1829 }
1830
1831 // The main routine called by a new Java thread. This isn't overridden
1832 // by subclasses, instead different subclasses define a different "entry_point"
1833 // which defines the actual logic for that kind of thread.
1834 void JavaThread::run() {
1835 // initialize thread-local alloc buffer related fields
1836 this->initialize_tlab();
1837
1838 // Used to test validity of stack trace backs.
1839 // This can't be moved into pre_run() else we invalidate
1840 // the requirement that thread_main_inner is lower on
1841 // the stack. Consequently all the initialization logic
1842 // stays here in run() rather than pre_run().
1843 this->record_base_of_stack_pointer();
1844
1845 this->create_stack_guard_pages();
1846
1847 this->cache_global_variables();
1848
1849 // Thread is now sufficiently initialized to be handled by the safepoint code as being
1850 // in the VM. Change thread state from _thread_new to _thread_in_vm
1851 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1852
1853 assert(JavaThread::current() == this, "sanity check");
1854 assert(!Thread::current()->owns_locks(), "sanity check");
1855
1856 DTRACE_THREAD_PROBE(start, this);
1857
1858 // This operation might block. We call that after all safepoint checks for a new thread has
1859 // been completed.
1860 this->set_active_handles(JNIHandleBlock::allocate_block());
1861
1862 if (JvmtiExport::should_post_thread_life()) {
1863 JvmtiExport::post_thread_start(this);
1864
1865 }
1866
1867 // We call another function to do the rest so we are sure that the stack addresses used
1868 // from there will be lower than the stack base just computed.
1869 thread_main_inner();
1870 }
1871
1872 void JavaThread::thread_main_inner() {
1873 assert(JavaThread::current() == this, "sanity check");
1874 assert(this->threadObj() != NULL, "just checking");
1875
1876 // Execute thread entry point unless this thread has a pending exception
1877 // or has been stopped before starting.
1878 // Note: Due to JVM_StopThread we can have pending exceptions already!
1879 if (!this->has_pending_exception() &&
1880 !java_lang_Thread::is_stillborn(this->threadObj())) {
1881 {
1882 ResourceMark rm(this);
1883 this->set_native_thread_name(this->get_thread_name());
1884 }
1885 HandleMark hm(this);
1886 this->entry_point()(this, this);
1887 }
1888
1889 DTRACE_THREAD_PROBE(stop, this);
1890
1891 // Cleanup is handled in post_run()
1892 }
1893
1894 // Shared teardown for all JavaThreads
1895 void JavaThread::post_run() {
1896 this->exit(false);
1897 // Defer deletion to here to ensure 'this' is still referenceable in call_run
1898 // for any shared tear-down.
1899 this->smr_delete();
1900 }
1901
1902 static void ensure_join(JavaThread* thread) {
1903 // We do not need to grab the Threads_lock, since we are operating on ourself.
1904 Handle threadObj(thread, thread->threadObj());
1905 assert(threadObj.not_null(), "java thread object must exist");
1906 ObjectLocker lock(threadObj, thread);
1907 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1908 thread->clear_pending_exception();
1909 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1910 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1911 // Clear the native thread instance - this makes isAlive return false and allows the join()
1912 // to complete once we've done the notify_all below
1913 java_lang_Thread::set_thread(threadObj(), NULL);
1914 lock.notify_all(thread);
1915 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1916 thread->clear_pending_exception();
1917 }
1918
1919 static bool is_daemon(oop threadObj) {
1920 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
1921 }
1922
1923 // For any new cleanup additions, please check to see if they need to be applied to
1924 // cleanup_failed_attach_current_thread as well.
1925 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1926 assert(this == JavaThread::current(), "thread consistency check");
1927
1928 elapsedTimer _timer_exit_phase1;
1929 elapsedTimer _timer_exit_phase2;
1930 elapsedTimer _timer_exit_phase3;
1931 elapsedTimer _timer_exit_phase4;
1932
1933 if (log_is_enabled(Debug, os, thread, timer)) {
1934 _timer_exit_phase1.start();
1935 }
1936
1937 HandleMark hm(this);
1938 Handle uncaught_exception(this, this->pending_exception());
1939 this->clear_pending_exception();
1940 Handle threadObj(this, this->threadObj());
1941 assert(threadObj.not_null(), "Java thread object should be created");
1942
1943 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1944 {
1945 EXCEPTION_MARK;
1946
1947 CLEAR_PENDING_EXCEPTION;
1948 }
1949 if (!destroy_vm) {
1950 if (uncaught_exception.not_null()) {
1951 EXCEPTION_MARK;
1952 // Call method Thread.dispatchUncaughtException().
1953 Klass* thread_klass = SystemDictionary::Thread_klass();
1954 JavaValue result(T_VOID);
1955 JavaCalls::call_virtual(&result,
1956 threadObj, thread_klass,
1957 vmSymbols::dispatchUncaughtException_name(),
1958 vmSymbols::throwable_void_signature(),
1959 uncaught_exception,
1960 THREAD);
1961 if (HAS_PENDING_EXCEPTION) {
1962 ResourceMark rm(this);
1963 jio_fprintf(defaultStream::error_stream(),
1964 "\nException: %s thrown from the UncaughtExceptionHandler"
1965 " in thread \"%s\"\n",
1966 pending_exception()->klass()->external_name(),
1967 get_thread_name());
1968 CLEAR_PENDING_EXCEPTION;
1969 }
1970 }
1971 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
1972
1973 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1974 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1975 // is deprecated anyhow.
1976 if (!is_Compiler_thread()) {
1977 int count = 3;
1978 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1979 EXCEPTION_MARK;
1980 JavaValue result(T_VOID);
1981 Klass* thread_klass = SystemDictionary::Thread_klass();
1982 JavaCalls::call_virtual(&result,
1983 threadObj, thread_klass,
1984 vmSymbols::exit_method_name(),
1985 vmSymbols::void_method_signature(),
1986 THREAD);
1987 CLEAR_PENDING_EXCEPTION;
1988 }
1989 }
1990 // notify JVMTI
1991 if (JvmtiExport::should_post_thread_life()) {
1992 JvmtiExport::post_thread_end(this);
1993 }
1994
1995 // We have notified the agents that we are exiting, before we go on,
1996 // we must check for a pending external suspend request and honor it
1997 // in order to not surprise the thread that made the suspend request.
1998 while (true) {
1999 {
2000 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2001 if (!is_external_suspend()) {
2002 set_terminated(_thread_exiting);
2003 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
2004 break;
2005 }
2006 // Implied else:
2007 // Things get a little tricky here. We have a pending external
2008 // suspend request, but we are holding the SR_lock so we
2009 // can't just self-suspend. So we temporarily drop the lock
2010 // and then self-suspend.
2011 }
2012
2013 ThreadBlockInVM tbivm(this);
2014 java_suspend_self();
2015
2016 // We're done with this suspend request, but we have to loop around
2017 // and check again. Eventually we will get SR_lock without a pending
2018 // external suspend request and will be able to mark ourselves as
2019 // exiting.
2020 }
2021 // no more external suspends are allowed at this point
2022 } else {
2023 assert(!is_terminated() && !is_exiting(), "must not be exiting");
2024 // before_exit() has already posted JVMTI THREAD_END events
2025 }
2026
2027 if (log_is_enabled(Debug, os, thread, timer)) {
2028 _timer_exit_phase1.stop();
2029 _timer_exit_phase2.start();
2030 }
2031 // Notify waiters on thread object. This has to be done after exit() is called
2032 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
2033 // group should have the destroyed bit set before waiters are notified).
2034 ensure_join(this);
2035 assert(!this->has_pending_exception(), "ensure_join should have cleared");
2036
2037 if (log_is_enabled(Debug, os, thread, timer)) {
2038 _timer_exit_phase2.stop();
2039 _timer_exit_phase3.start();
2040 }
2041 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
2042 // held by this thread must be released. The spec does not distinguish
2043 // between JNI-acquired and regular Java monitors. We can only see
2044 // regular Java monitors here if monitor enter-exit matching is broken.
2045 //
2046 // ensure_join() ignores IllegalThreadStateExceptions, and so does
2047 // ObjectSynchronizer::release_monitors_owned_by_thread().
2048 if (exit_type == jni_detach) {
2049 // Sanity check even though JNI DetachCurrentThread() would have
2050 // returned JNI_ERR if there was a Java frame. JavaThread exit
2051 // should be done executing Java code by the time we get here.
2052 assert(!this->has_last_Java_frame(),
2053 "should not have a Java frame when detaching or exiting");
2054 ObjectSynchronizer::release_monitors_owned_by_thread(this);
2055 assert(!this->has_pending_exception(), "release_monitors should have cleared");
2056 }
2057
2058 // These things needs to be done while we are still a Java Thread. Make sure that thread
2059 // is in a consistent state, in case GC happens
2060 JFR_ONLY(Jfr::on_thread_exit(this);)
2061
2062 if (active_handles() != NULL) {
2063 JNIHandleBlock* block = active_handles();
2064 set_active_handles(NULL);
2065 JNIHandleBlock::release_block(block);
2066 }
2067
2068 if (free_handle_block() != NULL) {
2069 JNIHandleBlock* block = free_handle_block();
2070 set_free_handle_block(NULL);
2071 JNIHandleBlock::release_block(block);
2072 }
2073
2074 // These have to be removed while this is still a valid thread.
2075 remove_stack_guard_pages();
2076
2077 if (UseTLAB) {
2078 tlab().retire();
2079 }
2080
2081 if (JvmtiEnv::environments_might_exist()) {
2082 JvmtiExport::cleanup_thread(this);
2083 }
2084
2085 // We must flush any deferred card marks and other various GC barrier
2086 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2087 // before removing a thread from the list of active threads.
2088 BarrierSet::barrier_set()->on_thread_detach(this);
2089
2090 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2091 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2092 os::current_thread_id());
2093
2094 if (log_is_enabled(Debug, os, thread, timer)) {
2095 _timer_exit_phase3.stop();
2096 _timer_exit_phase4.start();
2097 }
2098 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2099 Threads::remove(this);
2100
2101 if (log_is_enabled(Debug, os, thread, timer)) {
2102 _timer_exit_phase4.stop();
2103 ResourceMark rm(this);
2104 log_debug(os, thread, timer)("name='%s'"
2105 ", exit-phase1=" JLONG_FORMAT
2106 ", exit-phase2=" JLONG_FORMAT
2107 ", exit-phase3=" JLONG_FORMAT
2108 ", exit-phase4=" JLONG_FORMAT,
2109 get_thread_name(),
2110 _timer_exit_phase1.milliseconds(),
2111 _timer_exit_phase2.milliseconds(),
2112 _timer_exit_phase3.milliseconds(),
2113 _timer_exit_phase4.milliseconds());
2114 }
2115 }
2116
2117 void JavaThread::cleanup_failed_attach_current_thread() {
2118 if (active_handles() != NULL) {
2119 JNIHandleBlock* block = active_handles();
2120 set_active_handles(NULL);
2121 JNIHandleBlock::release_block(block);
2122 }
2123
2124 if (free_handle_block() != NULL) {
2125 JNIHandleBlock* block = free_handle_block();
2126 set_free_handle_block(NULL);
2127 JNIHandleBlock::release_block(block);
2128 }
2129
2130 // These have to be removed while this is still a valid thread.
2131 remove_stack_guard_pages();
2132
2133 if (UseTLAB) {
2134 tlab().retire();
2135 }
2136
2137 BarrierSet::barrier_set()->on_thread_detach(this);
2138
2139 Threads::remove(this);
2140 this->smr_delete();
2141 }
2142
2143 JavaThread* JavaThread::active() {
2144 Thread* thread = Thread::current();
2145 if (thread->is_Java_thread()) {
2146 return (JavaThread*) thread;
2147 } else {
2148 assert(thread->is_VM_thread(), "this must be a vm thread");
2149 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2150 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2151 assert(ret->is_Java_thread(), "must be a Java thread");
2152 return ret;
2153 }
2154 }
2155
2156 bool JavaThread::is_lock_owned(address adr) const {
2157 if (Thread::is_lock_owned(adr)) return true;
2158
2159 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2160 if (chunk->contains(adr)) return true;
2161 }
2162
2163 return false;
2164 }
2165
2166
2167 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2168 chunk->set_next(monitor_chunks());
2169 set_monitor_chunks(chunk);
2170 }
2171
2172 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2173 guarantee(monitor_chunks() != NULL, "must be non empty");
2174 if (monitor_chunks() == chunk) {
2175 set_monitor_chunks(chunk->next());
2176 } else {
2177 MonitorChunk* prev = monitor_chunks();
2178 while (prev->next() != chunk) prev = prev->next();
2179 prev->set_next(chunk->next());
2180 }
2181 }
2182
2183 // JVM support.
2184
2185 // Note: this function shouldn't block if it's called in
2186 // _thread_in_native_trans state (such as from
2187 // check_special_condition_for_native_trans()).
2188 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2189
2190 if (has_last_Java_frame() && has_async_condition()) {
2191 // If we are at a polling page safepoint (not a poll return)
2192 // then we must defer async exception because live registers
2193 // will be clobbered by the exception path. Poll return is
2194 // ok because the call we a returning from already collides
2195 // with exception handling registers and so there is no issue.
2196 // (The exception handling path kills call result registers but
2197 // this is ok since the exception kills the result anyway).
2198
2199 if (is_at_poll_safepoint()) {
2200 // if the code we are returning to has deoptimized we must defer
2201 // the exception otherwise live registers get clobbered on the
2202 // exception path before deoptimization is able to retrieve them.
2203 //
2204 RegisterMap map(this, false);
2205 frame caller_fr = last_frame().sender(&map);
2206 assert(caller_fr.is_compiled_frame(), "what?");
2207 if (caller_fr.is_deoptimized_frame()) {
2208 log_info(exceptions)("deferred async exception at compiled safepoint");
2209 return;
2210 }
2211 }
2212 }
2213
2214 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2215 if (condition == _no_async_condition) {
2216 // Conditions have changed since has_special_runtime_exit_condition()
2217 // was called:
2218 // - if we were here only because of an external suspend request,
2219 // then that was taken care of above (or cancelled) so we are done
2220 // - if we were here because of another async request, then it has
2221 // been cleared between the has_special_runtime_exit_condition()
2222 // and now so again we are done
2223 return;
2224 }
2225
2226 // Check for pending async. exception
2227 if (_pending_async_exception != NULL) {
2228 // Only overwrite an already pending exception, if it is not a threadDeath.
2229 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2230
2231 // We cannot call Exceptions::_throw(...) here because we cannot block
2232 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2233
2234 LogTarget(Info, exceptions) lt;
2235 if (lt.is_enabled()) {
2236 ResourceMark rm;
2237 LogStream ls(lt);
2238 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2239 if (has_last_Java_frame()) {
2240 frame f = last_frame();
2241 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2242 }
2243 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2244 }
2245 _pending_async_exception = NULL;
2246 clear_has_async_exception();
2247 }
2248 }
2249
2250 if (check_unsafe_error &&
2251 condition == _async_unsafe_access_error && !has_pending_exception()) {
2252 condition = _no_async_condition; // done
2253 switch (thread_state()) {
2254 case _thread_in_vm: {
2255 JavaThread* THREAD = this;
2256 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2257 }
2258 case _thread_in_native: {
2259 ThreadInVMfromNative tiv(this);
2260 JavaThread* THREAD = this;
2261 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2262 }
2263 case _thread_in_Java: {
2264 ThreadInVMfromJava tiv(this);
2265 JavaThread* THREAD = this;
2266 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2267 }
2268 default:
2269 ShouldNotReachHere();
2270 }
2271 }
2272
2273 assert(condition == _no_async_condition || has_pending_exception() ||
2274 (!check_unsafe_error && condition == _async_unsafe_access_error),
2275 "must have handled the async condition, if no exception");
2276 }
2277
2278 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2279 //
2280 // Check for pending external suspend. Internal suspend requests do
2281 // not use handle_special_runtime_exit_condition().
2282 // If JNIEnv proxies are allowed, don't self-suspend if the target
2283 // thread is not the current thread. In older versions of jdbx, jdbx
2284 // threads could call into the VM with another thread's JNIEnv so we
2285 // can be here operating on behalf of a suspended thread (4432884).
2286 bool do_self_suspend = is_external_suspend_with_lock();
2287 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2288 //
2289 // Because thread is external suspended the safepoint code will count
2290 // thread as at a safepoint. This can be odd because we can be here
2291 // as _thread_in_Java which would normally transition to _thread_blocked
2292 // at a safepoint. We would like to mark the thread as _thread_blocked
2293 // before calling java_suspend_self like all other callers of it but
2294 // we must then observe proper safepoint protocol. (We can't leave
2295 // _thread_blocked with a safepoint in progress). However we can be
2296 // here as _thread_in_native_trans so we can't use a normal transition
2297 // constructor/destructor pair because they assert on that type of
2298 // transition. We could do something like:
2299 //
2300 // JavaThreadState state = thread_state();
2301 // set_thread_state(_thread_in_vm);
2302 // {
2303 // ThreadBlockInVM tbivm(this);
2304 // java_suspend_self()
2305 // }
2306 // set_thread_state(_thread_in_vm_trans);
2307 // if (safepoint) block;
2308 // set_thread_state(state);
2309 //
2310 // but that is pretty messy. Instead we just go with the way the
2311 // code has worked before and note that this is the only path to
2312 // java_suspend_self that doesn't put the thread in _thread_blocked
2313 // mode.
2314
2315 frame_anchor()->make_walkable(this);
2316 java_suspend_self();
2317
2318 // We might be here for reasons in addition to the self-suspend request
2319 // so check for other async requests.
2320 }
2321
2322 if (check_asyncs) {
2323 check_and_handle_async_exceptions();
2324 }
2325
2326 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2327 }
2328
2329 void JavaThread::send_thread_stop(oop java_throwable) {
2330 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2331 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2332 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2333
2334 // Do not throw asynchronous exceptions against the compiler thread
2335 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2336 if (!can_call_java()) return;
2337
2338 {
2339 // Actually throw the Throwable against the target Thread - however
2340 // only if there is no thread death exception installed already.
2341 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2342 // If the topmost frame is a runtime stub, then we are calling into
2343 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2344 // must deoptimize the caller before continuing, as the compiled exception handler table
2345 // may not be valid
2346 if (has_last_Java_frame()) {
2347 frame f = last_frame();
2348 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2349 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2350 RegisterMap reg_map(this, UseBiasedLocking);
2351 frame compiled_frame = f.sender(®_map);
2352 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2353 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2354 }
2355 }
2356 }
2357
2358 // Set async. pending exception in thread.
2359 set_pending_async_exception(java_throwable);
2360
2361 if (log_is_enabled(Info, exceptions)) {
2362 ResourceMark rm;
2363 log_info(exceptions)("Pending Async. exception installed of type: %s",
2364 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2365 }
2366 // for AbortVMOnException flag
2367 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2368 }
2369 }
2370
2371
2372 // Interrupt thread so it will wake up from a potential wait()
2373 Thread::interrupt(this);
2374 }
2375
2376 // External suspension mechanism.
2377 //
2378 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2379 // to any VM_locks and it is at a transition
2380 // Self-suspension will happen on the transition out of the vm.
2381 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2382 //
2383 // Guarantees on return:
2384 // + Target thread will not execute any new bytecode (that's why we need to
2385 // force a safepoint)
2386 // + Target thread will not enter any new monitors
2387 //
2388 void JavaThread::java_suspend() {
2389 ThreadsListHandle tlh;
2390 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2391 return;
2392 }
2393
2394 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2395 if (!is_external_suspend()) {
2396 // a racing resume has cancelled us; bail out now
2397 return;
2398 }
2399
2400 // suspend is done
2401 uint32_t debug_bits = 0;
2402 // Warning: is_ext_suspend_completed() may temporarily drop the
2403 // SR_lock to allow the thread to reach a stable thread state if
2404 // it is currently in a transient thread state.
2405 if (is_ext_suspend_completed(false /* !called_by_wait */,
2406 SuspendRetryDelay, &debug_bits)) {
2407 return;
2408 }
2409 }
2410
2411 if (Thread::current() == this) {
2412 // Safely self-suspend.
2413 // If we don't do this explicitly it will implicitly happen
2414 // before we transition back to Java, and on some other thread-state
2415 // transition paths, but not as we exit a JVM TI SuspendThread call.
2416 // As SuspendThread(current) must not return (until resumed) we must
2417 // self-suspend here.
2418 ThreadBlockInVM tbivm(this);
2419 java_suspend_self();
2420 } else {
2421 VM_ThreadSuspend vm_suspend;
2422 VMThread::execute(&vm_suspend);
2423 }
2424 }
2425
2426 // Part II of external suspension.
2427 // A JavaThread self suspends when it detects a pending external suspend
2428 // request. This is usually on transitions. It is also done in places
2429 // where continuing to the next transition would surprise the caller,
2430 // e.g., monitor entry.
2431 //
2432 // Returns the number of times that the thread self-suspended.
2433 //
2434 // Note: DO NOT call java_suspend_self() when you just want to block current
2435 // thread. java_suspend_self() is the second stage of cooperative
2436 // suspension for external suspend requests and should only be used
2437 // to complete an external suspend request.
2438 //
2439 int JavaThread::java_suspend_self() {
2440 int ret = 0;
2441
2442 // we are in the process of exiting so don't suspend
2443 if (is_exiting()) {
2444 clear_external_suspend();
2445 return ret;
2446 }
2447
2448 assert(_anchor.walkable() ||
2449 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2450 "must have walkable stack");
2451
2452 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2453
2454 assert(!this->is_ext_suspended(),
2455 "a thread trying to self-suspend should not already be suspended");
2456
2457 if (this->is_suspend_equivalent()) {
2458 // If we are self-suspending as a result of the lifting of a
2459 // suspend equivalent condition, then the suspend_equivalent
2460 // flag is not cleared until we set the ext_suspended flag so
2461 // that wait_for_ext_suspend_completion() returns consistent
2462 // results.
2463 this->clear_suspend_equivalent();
2464 }
2465
2466 // A racing resume may have cancelled us before we grabbed SR_lock
2467 // above. Or another external suspend request could be waiting for us
2468 // by the time we return from SR_lock()->wait(). The thread
2469 // that requested the suspension may already be trying to walk our
2470 // stack and if we return now, we can change the stack out from under
2471 // it. This would be a "bad thing (TM)" and cause the stack walker
2472 // to crash. We stay self-suspended until there are no more pending
2473 // external suspend requests.
2474 while (is_external_suspend()) {
2475 ret++;
2476 this->set_ext_suspended();
2477
2478 // _ext_suspended flag is cleared by java_resume()
2479 while (is_ext_suspended()) {
2480 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2481 }
2482 }
2483
2484 return ret;
2485 }
2486
2487 #ifdef ASSERT
2488 // Verify the JavaThread has not yet been published in the Threads::list, and
2489 // hence doesn't need protection from concurrent access at this stage.
2490 void JavaThread::verify_not_published() {
2491 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2492 // since an unpublished JavaThread doesn't participate in the
2493 // Thread-SMR protocol for keeping a ThreadsList alive.
2494 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2495 }
2496 #endif
2497
2498 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2499 // progress or when _suspend_flags is non-zero.
2500 // Current thread needs to self-suspend if there is a suspend request and/or
2501 // block if a safepoint is in progress.
2502 // Async exception ISN'T checked.
2503 // Note only the ThreadInVMfromNative transition can call this function
2504 // directly and when thread state is _thread_in_native_trans
2505 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2506 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2507
2508 JavaThread *curJT = JavaThread::current();
2509 bool do_self_suspend = thread->is_external_suspend();
2510
2511 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2512
2513 // If JNIEnv proxies are allowed, don't self-suspend if the target
2514 // thread is not the current thread. In older versions of jdbx, jdbx
2515 // threads could call into the VM with another thread's JNIEnv so we
2516 // can be here operating on behalf of a suspended thread (4432884).
2517 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2518 JavaThreadState state = thread->thread_state();
2519
2520 // We mark this thread_blocked state as a suspend-equivalent so
2521 // that a caller to is_ext_suspend_completed() won't be confused.
2522 // The suspend-equivalent state is cleared by java_suspend_self().
2523 thread->set_suspend_equivalent();
2524
2525 // If the safepoint code sees the _thread_in_native_trans state, it will
2526 // wait until the thread changes to other thread state. There is no
2527 // guarantee on how soon we can obtain the SR_lock and complete the
2528 // self-suspend request. It would be a bad idea to let safepoint wait for
2529 // too long. Temporarily change the state to _thread_blocked to
2530 // let the VM thread know that this thread is ready for GC. The problem
2531 // of changing thread state is that safepoint could happen just after
2532 // java_suspend_self() returns after being resumed, and VM thread will
2533 // see the _thread_blocked state. We must check for safepoint
2534 // after restoring the state and make sure we won't leave while a safepoint
2535 // is in progress.
2536 thread->set_thread_state(_thread_blocked);
2537 thread->java_suspend_self();
2538 thread->set_thread_state(state);
2539
2540 InterfaceSupport::serialize_thread_state_with_handler(thread);
2541 }
2542
2543 SafepointMechanism::block_if_requested(curJT);
2544
2545 if (thread->is_deopt_suspend()) {
2546 thread->clear_deopt_suspend();
2547 RegisterMap map(thread, false);
2548 frame f = thread->last_frame();
2549 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2550 f = f.sender(&map);
2551 }
2552 if (f.id() == thread->must_deopt_id()) {
2553 thread->clear_must_deopt_id();
2554 f.deoptimize(thread);
2555 } else {
2556 fatal("missed deoptimization!");
2557 }
2558 }
2559
2560 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2561 }
2562
2563 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2564 // progress or when _suspend_flags is non-zero.
2565 // Current thread needs to self-suspend if there is a suspend request and/or
2566 // block if a safepoint is in progress.
2567 // Also check for pending async exception (not including unsafe access error).
2568 // Note only the native==>VM/Java barriers can call this function and when
2569 // thread state is _thread_in_native_trans.
2570 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2571 check_safepoint_and_suspend_for_native_trans(thread);
2572
2573 if (thread->has_async_exception()) {
2574 // We are in _thread_in_native_trans state, don't handle unsafe
2575 // access error since that may block.
2576 thread->check_and_handle_async_exceptions(false);
2577 }
2578 }
2579
2580 // This is a variant of the normal
2581 // check_special_condition_for_native_trans with slightly different
2582 // semantics for use by critical native wrappers. It does all the
2583 // normal checks but also performs the transition back into
2584 // thread_in_Java state. This is required so that critical natives
2585 // can potentially block and perform a GC if they are the last thread
2586 // exiting the GCLocker.
2587 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2588 check_special_condition_for_native_trans(thread);
2589
2590 // Finish the transition
2591 thread->set_thread_state(_thread_in_Java);
2592
2593 if (thread->do_critical_native_unlock()) {
2594 ThreadInVMfromJavaNoAsyncException tiv(thread);
2595 GCLocker::unlock_critical(thread);
2596 thread->clear_critical_native_unlock();
2597 }
2598 }
2599
2600 // We need to guarantee the Threads_lock here, since resumes are not
2601 // allowed during safepoint synchronization
2602 // Can only resume from an external suspension
2603 void JavaThread::java_resume() {
2604 assert_locked_or_safepoint(Threads_lock);
2605
2606 // Sanity check: thread is gone, has started exiting or the thread
2607 // was not externally suspended.
2608 ThreadsListHandle tlh;
2609 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2610 return;
2611 }
2612
2613 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2614
2615 clear_external_suspend();
2616
2617 if (is_ext_suspended()) {
2618 clear_ext_suspended();
2619 SR_lock()->notify_all();
2620 }
2621 }
2622
2623 size_t JavaThread::_stack_red_zone_size = 0;
2624 size_t JavaThread::_stack_yellow_zone_size = 0;
2625 size_t JavaThread::_stack_reserved_zone_size = 0;
2626 size_t JavaThread::_stack_shadow_zone_size = 0;
2627
2628 void JavaThread::create_stack_guard_pages() {
2629 if (!os::uses_stack_guard_pages() ||
2630 _stack_guard_state != stack_guard_unused ||
2631 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2632 log_info(os, thread)("Stack guard page creation for thread "
2633 UINTX_FORMAT " disabled", os::current_thread_id());
2634 return;
2635 }
2636 address low_addr = stack_end();
2637 size_t len = stack_guard_zone_size();
2638
2639 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2640 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2641
2642 int must_commit = os::must_commit_stack_guard_pages();
2643 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2644
2645 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2646 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2647 return;
2648 }
2649
2650 if (os::guard_memory((char *) low_addr, len)) {
2651 _stack_guard_state = stack_guard_enabled;
2652 } else {
2653 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2654 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2655 if (os::uncommit_memory((char *) low_addr, len)) {
2656 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2657 }
2658 return;
2659 }
2660
2661 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2662 PTR_FORMAT "-" PTR_FORMAT ".",
2663 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2664 }
2665
2666 void JavaThread::remove_stack_guard_pages() {
2667 assert(Thread::current() == this, "from different thread");
2668 if (_stack_guard_state == stack_guard_unused) return;
2669 address low_addr = stack_end();
2670 size_t len = stack_guard_zone_size();
2671
2672 if (os::must_commit_stack_guard_pages()) {
2673 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2674 _stack_guard_state = stack_guard_unused;
2675 } else {
2676 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2677 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2678 return;
2679 }
2680 } else {
2681 if (_stack_guard_state == stack_guard_unused) return;
2682 if (os::unguard_memory((char *) low_addr, len)) {
2683 _stack_guard_state = stack_guard_unused;
2684 } else {
2685 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2686 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2687 return;
2688 }
2689 }
2690
2691 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2692 PTR_FORMAT "-" PTR_FORMAT ".",
2693 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2694 }
2695
2696 void JavaThread::enable_stack_reserved_zone() {
2697 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state");
2698
2699 // The base notation is from the stack's point of view, growing downward.
2700 // We need to adjust it to work correctly with guard_memory()
2701 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2702
2703 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2704 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2705
2706 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2707 _stack_guard_state = stack_guard_enabled;
2708 } else {
2709 warning("Attempt to guard stack reserved zone failed.");
2710 }
2711 enable_register_stack_guard();
2712 }
2713
2714 void JavaThread::disable_stack_reserved_zone() {
2715 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state");
2716
2717 // Simply return if called for a thread that does not use guard pages.
2718 if (_stack_guard_state != stack_guard_enabled) return;
2719
2720 // The base notation is from the stack's point of view, growing downward.
2721 // We need to adjust it to work correctly with guard_memory()
2722 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2723
2724 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2725 _stack_guard_state = stack_guard_reserved_disabled;
2726 } else {
2727 warning("Attempt to unguard stack reserved zone failed.");
2728 }
2729 disable_register_stack_guard();
2730 }
2731
2732 void JavaThread::enable_stack_yellow_reserved_zone() {
2733 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2734 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2735
2736 // The base notation is from the stacks point of view, growing downward.
2737 // We need to adjust it to work correctly with guard_memory()
2738 address base = stack_red_zone_base();
2739
2740 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2741 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2742
2743 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2744 _stack_guard_state = stack_guard_enabled;
2745 } else {
2746 warning("Attempt to guard stack yellow zone failed.");
2747 }
2748 enable_register_stack_guard();
2749 }
2750
2751 void JavaThread::disable_stack_yellow_reserved_zone() {
2752 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2753 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2754
2755 // Simply return if called for a thread that does not use guard pages.
2756 if (_stack_guard_state == stack_guard_unused) return;
2757
2758 // The base notation is from the stacks point of view, growing downward.
2759 // We need to adjust it to work correctly with guard_memory()
2760 address base = stack_red_zone_base();
2761
2762 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2763 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2764 } else {
2765 warning("Attempt to unguard stack yellow zone failed.");
2766 }
2767 disable_register_stack_guard();
2768 }
2769
2770 void JavaThread::enable_stack_red_zone() {
2771 // The base notation is from the stacks point of view, growing downward.
2772 // We need to adjust it to work correctly with guard_memory()
2773 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2774 address base = stack_red_zone_base() - stack_red_zone_size();
2775
2776 guarantee(base < stack_base(), "Error calculating stack red zone");
2777 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2778
2779 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2780 warning("Attempt to guard stack red zone failed.");
2781 }
2782 }
2783
2784 void JavaThread::disable_stack_red_zone() {
2785 // The base notation is from the stacks point of view, growing downward.
2786 // We need to adjust it to work correctly with guard_memory()
2787 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2788 address base = stack_red_zone_base() - stack_red_zone_size();
2789 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2790 warning("Attempt to unguard stack red zone failed.");
2791 }
2792 }
2793
2794 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2795 // ignore is there is no stack
2796 if (!has_last_Java_frame()) return;
2797 // traverse the stack frames. Starts from top frame.
2798 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2799 frame* fr = fst.current();
2800 f(fr, fst.register_map());
2801 }
2802 }
2803
2804
2805 #ifndef PRODUCT
2806 // Deoptimization
2807 // Function for testing deoptimization
2808 void JavaThread::deoptimize() {
2809 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2810 StackFrameStream fst(this, UseBiasedLocking);
2811 bool deopt = false; // Dump stack only if a deopt actually happens.
2812 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2813 // Iterate over all frames in the thread and deoptimize
2814 for (; !fst.is_done(); fst.next()) {
2815 if (fst.current()->can_be_deoptimized()) {
2816
2817 if (only_at) {
2818 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2819 // consists of comma or carriage return separated numbers so
2820 // search for the current bci in that string.
2821 address pc = fst.current()->pc();
2822 nmethod* nm = (nmethod*) fst.current()->cb();
2823 ScopeDesc* sd = nm->scope_desc_at(pc);
2824 char buffer[8];
2825 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2826 size_t len = strlen(buffer);
2827 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2828 while (found != NULL) {
2829 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2830 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2831 // Check that the bci found is bracketed by terminators.
2832 break;
2833 }
2834 found = strstr(found + 1, buffer);
2835 }
2836 if (!found) {
2837 continue;
2838 }
2839 }
2840
2841 if (DebugDeoptimization && !deopt) {
2842 deopt = true; // One-time only print before deopt
2843 tty->print_cr("[BEFORE Deoptimization]");
2844 trace_frames();
2845 trace_stack();
2846 }
2847 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2848 }
2849 }
2850
2851 if (DebugDeoptimization && deopt) {
2852 tty->print_cr("[AFTER Deoptimization]");
2853 trace_frames();
2854 }
2855 }
2856
2857
2858 // Make zombies
2859 void JavaThread::make_zombies() {
2860 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2861 if (fst.current()->can_be_deoptimized()) {
2862 // it is a Java nmethod
2863 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2864 nm->make_not_entrant();
2865 }
2866 }
2867 }
2868 #endif // PRODUCT
2869
2870
2871 void JavaThread::deoptimized_wrt_marked_nmethods() {
2872 if (!has_last_Java_frame()) return;
2873 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2874 StackFrameStream fst(this, UseBiasedLocking);
2875 for (; !fst.is_done(); fst.next()) {
2876 if (fst.current()->should_be_deoptimized()) {
2877 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2878 }
2879 }
2880 }
2881
2882
2883 // If the caller is a NamedThread, then remember, in the current scope,
2884 // the given JavaThread in its _processed_thread field.
2885 class RememberProcessedThread: public StackObj {
2886 NamedThread* _cur_thr;
2887 public:
2888 RememberProcessedThread(JavaThread* jthr) {
2889 Thread* thread = Thread::current();
2890 if (thread->is_Named_thread()) {
2891 _cur_thr = (NamedThread *)thread;
2892 _cur_thr->set_processed_thread(jthr);
2893 } else {
2894 _cur_thr = NULL;
2895 }
2896 }
2897
2898 ~RememberProcessedThread() {
2899 if (_cur_thr) {
2900 _cur_thr->set_processed_thread(NULL);
2901 }
2902 }
2903 };
2904
2905 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2906 // Verify that the deferred card marks have been flushed.
2907 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2908
2909 // Traverse the GCHandles
2910 Thread::oops_do(f, cf);
2911
2912 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2913 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2914
2915 if (has_last_Java_frame()) {
2916 // Record JavaThread to GC thread
2917 RememberProcessedThread rpt(this);
2918
2919 // traverse the registered growable array
2920 if (_array_for_gc != NULL) {
2921 for (int index = 0; index < _array_for_gc->length(); index++) {
2922 f->do_oop(_array_for_gc->adr_at(index));
2923 }
2924 }
2925
2926 // Traverse the monitor chunks
2927 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2928 chunk->oops_do(f);
2929 }
2930
2931 // Traverse the execution stack
2932 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2933 fst.current()->oops_do(f, cf, fst.register_map());
2934 }
2935 }
2936
2937 // callee_target is never live across a gc point so NULL it here should
2938 // it still contain a methdOop.
2939
2940 set_callee_target(NULL);
2941
2942 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2943 // If we have deferred set_locals there might be oops waiting to be
2944 // written
2945 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2946 if (list != NULL) {
2947 for (int i = 0; i < list->length(); i++) {
2948 list->at(i)->oops_do(f);
2949 }
2950 }
2951
2952 // Traverse instance variables at the end since the GC may be moving things
2953 // around using this function
2954 f->do_oop((oop*) &_threadObj);
2955 f->do_oop((oop*) &_vm_result);
2956 f->do_oop((oop*) &_exception_oop);
2957 f->do_oop((oop*) &_pending_async_exception);
2958
2959 if (jvmti_thread_state() != NULL) {
2960 jvmti_thread_state()->oops_do(f);
2961 }
2962 }
2963
2964 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2965 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2966 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2967
2968 if (has_last_Java_frame()) {
2969 // Traverse the execution stack
2970 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2971 fst.current()->nmethods_do(cf);
2972 }
2973 }
2974 }
2975
2976 void JavaThread::metadata_do(void f(Metadata*)) {
2977 if (has_last_Java_frame()) {
2978 // Traverse the execution stack to call f() on the methods in the stack
2979 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2980 fst.current()->metadata_do(f);
2981 }
2982 } else if (is_Compiler_thread()) {
2983 // need to walk ciMetadata in current compile tasks to keep alive.
2984 CompilerThread* ct = (CompilerThread*)this;
2985 if (ct->env() != NULL) {
2986 ct->env()->metadata_do(f);
2987 }
2988 CompileTask* task = ct->task();
2989 if (task != NULL) {
2990 task->metadata_do(f);
2991 }
2992 }
2993 }
2994
2995 // Printing
2996 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2997 switch (_thread_state) {
2998 case _thread_uninitialized: return "_thread_uninitialized";
2999 case _thread_new: return "_thread_new";
3000 case _thread_new_trans: return "_thread_new_trans";
3001 case _thread_in_native: return "_thread_in_native";
3002 case _thread_in_native_trans: return "_thread_in_native_trans";
3003 case _thread_in_vm: return "_thread_in_vm";
3004 case _thread_in_vm_trans: return "_thread_in_vm_trans";
3005 case _thread_in_Java: return "_thread_in_Java";
3006 case _thread_in_Java_trans: return "_thread_in_Java_trans";
3007 case _thread_blocked: return "_thread_blocked";
3008 case _thread_blocked_trans: return "_thread_blocked_trans";
3009 default: return "unknown thread state";
3010 }
3011 }
3012
3013 #ifndef PRODUCT
3014 void JavaThread::print_thread_state_on(outputStream *st) const {
3015 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
3016 };
3017 void JavaThread::print_thread_state() const {
3018 print_thread_state_on(tty);
3019 }
3020 #endif // PRODUCT
3021
3022 // Called by Threads::print() for VM_PrintThreads operation
3023 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
3024 st->print_raw("\"");
3025 st->print_raw(get_thread_name());
3026 st->print_raw("\" ");
3027 oop thread_oop = threadObj();
3028 if (thread_oop != NULL) {
3029 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
3030 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
3031 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
3032 }
3033 Thread::print_on(st, print_extended_info);
3034 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
3035 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
3036 if (thread_oop != NULL) {
3037 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3038 }
3039 #ifndef PRODUCT
3040 _safepoint_state->print_on(st);
3041 #endif // PRODUCT
3042 if (is_Compiler_thread()) {
3043 CompileTask *task = ((CompilerThread*)this)->task();
3044 if (task != NULL) {
3045 st->print(" Compiling: ");
3046 task->print(st, NULL, true, false);
3047 } else {
3048 st->print(" No compile task");
3049 }
3050 st->cr();
3051 }
3052 }
3053
3054 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3055 st->print("%s", get_thread_name_string(buf, buflen));
3056 }
3057
3058 // Called by fatal error handler. The difference between this and
3059 // JavaThread::print() is that we can't grab lock or allocate memory.
3060 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3061 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3062 oop thread_obj = threadObj();
3063 if (thread_obj != NULL) {
3064 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3065 }
3066 st->print(" [");
3067 st->print("%s", _get_thread_state_name(_thread_state));
3068 if (osthread()) {
3069 st->print(", id=%d", osthread()->thread_id());
3070 }
3071 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3072 p2i(stack_end()), p2i(stack_base()));
3073 st->print("]");
3074
3075 ThreadsSMRSupport::print_info_on(this, st);
3076 return;
3077 }
3078
3079 // Verification
3080
3081 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3082
3083 void JavaThread::verify() {
3084 // Verify oops in the thread.
3085 oops_do(&VerifyOopClosure::verify_oop, NULL);
3086
3087 // Verify the stack frames.
3088 frames_do(frame_verify);
3089 }
3090
3091 // CR 6300358 (sub-CR 2137150)
3092 // Most callers of this method assume that it can't return NULL but a
3093 // thread may not have a name whilst it is in the process of attaching to
3094 // the VM - see CR 6412693, and there are places where a JavaThread can be
3095 // seen prior to having it's threadObj set (eg JNI attaching threads and
3096 // if vm exit occurs during initialization). These cases can all be accounted
3097 // for such that this method never returns NULL.
3098 const char* JavaThread::get_thread_name() const {
3099 #ifdef ASSERT
3100 // early safepoints can hit while current thread does not yet have TLS
3101 if (!SafepointSynchronize::is_at_safepoint()) {
3102 Thread *cur = Thread::current();
3103 if (!(cur->is_Java_thread() && cur == this)) {
3104 // Current JavaThreads are allowed to get their own name without
3105 // the Threads_lock.
3106 assert_locked_or_safepoint(Threads_lock);
3107 }
3108 }
3109 #endif // ASSERT
3110 return get_thread_name_string();
3111 }
3112
3113 // Returns a non-NULL representation of this thread's name, or a suitable
3114 // descriptive string if there is no set name
3115 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3116 const char* name_str;
3117 oop thread_obj = threadObj();
3118 if (thread_obj != NULL) {
3119 oop name = java_lang_Thread::name(thread_obj);
3120 if (name != NULL) {
3121 if (buf == NULL) {
3122 name_str = java_lang_String::as_utf8_string(name);
3123 } else {
3124 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3125 }
3126 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3127 name_str = "<no-name - thread is attaching>";
3128 } else {
3129 name_str = Thread::name();
3130 }
3131 } else {
3132 name_str = Thread::name();
3133 }
3134 assert(name_str != NULL, "unexpected NULL thread name");
3135 return name_str;
3136 }
3137
3138
3139 const char* JavaThread::get_threadgroup_name() const {
3140 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3141 oop thread_obj = threadObj();
3142 if (thread_obj != NULL) {
3143 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3144 if (thread_group != NULL) {
3145 // ThreadGroup.name can be null
3146 return java_lang_ThreadGroup::name(thread_group);
3147 }
3148 }
3149 return NULL;
3150 }
3151
3152 const char* JavaThread::get_parent_name() const {
3153 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3154 oop thread_obj = threadObj();
3155 if (thread_obj != NULL) {
3156 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3157 if (thread_group != NULL) {
3158 oop parent = java_lang_ThreadGroup::parent(thread_group);
3159 if (parent != NULL) {
3160 // ThreadGroup.name can be null
3161 return java_lang_ThreadGroup::name(parent);
3162 }
3163 }
3164 }
3165 return NULL;
3166 }
3167
3168 ThreadPriority JavaThread::java_priority() const {
3169 oop thr_oop = threadObj();
3170 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3171 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3172 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3173 return priority;
3174 }
3175
3176 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3177
3178 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3179 // Link Java Thread object <-> C++ Thread
3180
3181 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3182 // and put it into a new Handle. The Handle "thread_oop" can then
3183 // be used to pass the C++ thread object to other methods.
3184
3185 // Set the Java level thread object (jthread) field of the
3186 // new thread (a JavaThread *) to C++ thread object using the
3187 // "thread_oop" handle.
3188
3189 // Set the thread field (a JavaThread *) of the
3190 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3191
3192 Handle thread_oop(Thread::current(),
3193 JNIHandles::resolve_non_null(jni_thread));
3194 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3195 "must be initialized");
3196 set_threadObj(thread_oop());
3197 java_lang_Thread::set_thread(thread_oop(), this);
3198
3199 if (prio == NoPriority) {
3200 prio = java_lang_Thread::priority(thread_oop());
3201 assert(prio != NoPriority, "A valid priority should be present");
3202 }
3203
3204 // Push the Java priority down to the native thread; needs Threads_lock
3205 Thread::set_priority(this, prio);
3206
3207 // Add the new thread to the Threads list and set it in motion.
3208 // We must have threads lock in order to call Threads::add.
3209 // It is crucial that we do not block before the thread is
3210 // added to the Threads list for if a GC happens, then the java_thread oop
3211 // will not be visited by GC.
3212 Threads::add(this);
3213 }
3214
3215 oop JavaThread::current_park_blocker() {
3216 // Support for JSR-166 locks
3217 oop thread_oop = threadObj();
3218 if (thread_oop != NULL &&
3219 JDK_Version::current().supports_thread_park_blocker()) {
3220 return java_lang_Thread::park_blocker(thread_oop);
3221 }
3222 return NULL;
3223 }
3224
3225
3226 void JavaThread::print_stack_on(outputStream* st) {
3227 if (!has_last_Java_frame()) return;
3228 ResourceMark rm;
3229 HandleMark hm;
3230
3231 RegisterMap reg_map(this);
3232 vframe* start_vf = last_java_vframe(®_map);
3233 int count = 0;
3234 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3235 if (f->is_java_frame()) {
3236 javaVFrame* jvf = javaVFrame::cast(f);
3237 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3238
3239 // Print out lock information
3240 if (JavaMonitorsInStackTrace) {
3241 jvf->print_lock_info_on(st, count);
3242 }
3243 } else {
3244 // Ignore non-Java frames
3245 }
3246
3247 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3248 count++;
3249 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3250 }
3251 }
3252
3253
3254 // JVMTI PopFrame support
3255 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3256 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3257 if (in_bytes(size_in_bytes) != 0) {
3258 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3259 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3260 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3261 }
3262 }
3263
3264 void* JavaThread::popframe_preserved_args() {
3265 return _popframe_preserved_args;
3266 }
3267
3268 ByteSize JavaThread::popframe_preserved_args_size() {
3269 return in_ByteSize(_popframe_preserved_args_size);
3270 }
3271
3272 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3273 int sz = in_bytes(popframe_preserved_args_size());
3274 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3275 return in_WordSize(sz / wordSize);
3276 }
3277
3278 void JavaThread::popframe_free_preserved_args() {
3279 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3280 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3281 _popframe_preserved_args = NULL;
3282 _popframe_preserved_args_size = 0;
3283 }
3284
3285 #ifndef PRODUCT
3286
3287 void JavaThread::trace_frames() {
3288 tty->print_cr("[Describe stack]");
3289 int frame_no = 1;
3290 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3291 tty->print(" %d. ", frame_no++);
3292 fst.current()->print_value_on(tty, this);
3293 tty->cr();
3294 }
3295 }
3296
3297 class PrintAndVerifyOopClosure: public OopClosure {
3298 protected:
3299 template <class T> inline void do_oop_work(T* p) {
3300 oop obj = RawAccess<>::oop_load(p);
3301 if (obj == NULL) return;
3302 tty->print(INTPTR_FORMAT ": ", p2i(p));
3303 if (oopDesc::is_oop_or_null(obj)) {
3304 if (obj->is_objArray()) {
3305 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3306 } else {
3307 obj->print();
3308 }
3309 } else {
3310 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3311 }
3312 tty->cr();
3313 }
3314 public:
3315 virtual void do_oop(oop* p) { do_oop_work(p); }
3316 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3317 };
3318
3319
3320 static void oops_print(frame* f, const RegisterMap *map) {
3321 PrintAndVerifyOopClosure print;
3322 f->print_value();
3323 f->oops_do(&print, NULL, (RegisterMap*)map);
3324 }
3325
3326 // Print our all the locations that contain oops and whether they are
3327 // valid or not. This useful when trying to find the oldest frame
3328 // where an oop has gone bad since the frame walk is from youngest to
3329 // oldest.
3330 void JavaThread::trace_oops() {
3331 tty->print_cr("[Trace oops]");
3332 frames_do(oops_print);
3333 }
3334
3335
3336 #ifdef ASSERT
3337 // Print or validate the layout of stack frames
3338 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3339 ResourceMark rm;
3340 PRESERVE_EXCEPTION_MARK;
3341 FrameValues values;
3342 int frame_no = 0;
3343 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3344 fst.current()->describe(values, ++frame_no);
3345 if (depth == frame_no) break;
3346 }
3347 if (validate_only) {
3348 values.validate();
3349 } else {
3350 tty->print_cr("[Describe stack layout]");
3351 values.print(this);
3352 }
3353 }
3354 #endif
3355
3356 void JavaThread::trace_stack_from(vframe* start_vf) {
3357 ResourceMark rm;
3358 int vframe_no = 1;
3359 for (vframe* f = start_vf; f; f = f->sender()) {
3360 if (f->is_java_frame()) {
3361 javaVFrame::cast(f)->print_activation(vframe_no++);
3362 } else {
3363 f->print();
3364 }
3365 if (vframe_no > StackPrintLimit) {
3366 tty->print_cr("...<more frames>...");
3367 return;
3368 }
3369 }
3370 }
3371
3372
3373 void JavaThread::trace_stack() {
3374 if (!has_last_Java_frame()) return;
3375 ResourceMark rm;
3376 HandleMark hm;
3377 RegisterMap reg_map(this);
3378 trace_stack_from(last_java_vframe(®_map));
3379 }
3380
3381
3382 #endif // PRODUCT
3383
3384
3385 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3386 assert(reg_map != NULL, "a map must be given");
3387 frame f = last_frame();
3388 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3389 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3390 }
3391 return NULL;
3392 }
3393
3394
3395 Klass* JavaThread::security_get_caller_class(int depth) {
3396 vframeStream vfst(this);
3397 vfst.security_get_caller_frame(depth);
3398 if (!vfst.at_end()) {
3399 return vfst.method()->method_holder();
3400 }
3401 return NULL;
3402 }
3403
3404 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3405 assert(thread->is_Compiler_thread(), "must be compiler thread");
3406 CompileBroker::compiler_thread_loop();
3407 }
3408
3409 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3410 NMethodSweeper::sweeper_loop();
3411 }
3412
3413 // Create a CompilerThread
3414 CompilerThread::CompilerThread(CompileQueue* queue,
3415 CompilerCounters* counters)
3416 : JavaThread(&compiler_thread_entry) {
3417 _env = NULL;
3418 _log = NULL;
3419 _task = NULL;
3420 _queue = queue;
3421 _counters = counters;
3422 _buffer_blob = NULL;
3423 _compiler = NULL;
3424
3425 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3426 resource_area()->bias_to(mtCompiler);
3427
3428 #ifndef PRODUCT
3429 _ideal_graph_printer = NULL;
3430 #endif
3431 }
3432
3433 CompilerThread::~CompilerThread() {
3434 // Delete objects which were allocated on heap.
3435 delete _counters;
3436 }
3437
3438 bool CompilerThread::can_call_java() const {
3439 return _compiler != NULL && _compiler->is_jvmci();
3440 }
3441
3442 // Create sweeper thread
3443 CodeCacheSweeperThread::CodeCacheSweeperThread()
3444 : JavaThread(&sweeper_thread_entry) {
3445 _scanned_compiled_method = NULL;
3446 }
3447
3448 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3449 JavaThread::oops_do(f, cf);
3450 if (_scanned_compiled_method != NULL && cf != NULL) {
3451 // Safepoints can occur when the sweeper is scanning an nmethod so
3452 // process it here to make sure it isn't unloaded in the middle of
3453 // a scan.
3454 cf->do_code_blob(_scanned_compiled_method);
3455 }
3456 }
3457
3458 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3459 JavaThread::nmethods_do(cf);
3460 if (_scanned_compiled_method != NULL && cf != NULL) {
3461 // Safepoints can occur when the sweeper is scanning an nmethod so
3462 // process it here to make sure it isn't unloaded in the middle of
3463 // a scan.
3464 cf->do_code_blob(_scanned_compiled_method);
3465 }
3466 }
3467
3468
3469 // ======= Threads ========
3470
3471 // The Threads class links together all active threads, and provides
3472 // operations over all threads. It is protected by the Threads_lock,
3473 // which is also used in other global contexts like safepointing.
3474 // ThreadsListHandles are used to safely perform operations on one
3475 // or more threads without the risk of the thread exiting during the
3476 // operation.
3477 //
3478 // Note: The Threads_lock is currently more widely used than we
3479 // would like. We are actively migrating Threads_lock uses to other
3480 // mechanisms in order to reduce Threads_lock contention.
3481
3482 JavaThread* Threads::_thread_list = NULL;
3483 int Threads::_number_of_threads = 0;
3484 int Threads::_number_of_non_daemon_threads = 0;
3485 int Threads::_return_code = 0;
3486 int Threads::_thread_claim_parity = 0;
3487 size_t JavaThread::_stack_size_at_create = 0;
3488
3489 #ifdef ASSERT
3490 bool Threads::_vm_complete = false;
3491 #endif
3492
3493 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3494 Prefetch::read((void*)addr, prefetch_interval);
3495 return *addr;
3496 }
3497
3498 // Possibly the ugliest for loop the world has seen. C++ does not allow
3499 // multiple types in the declaration section of the for loop. In this case
3500 // we are only dealing with pointers and hence can cast them. It looks ugly
3501 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3502 #define DO_JAVA_THREADS(LIST, X) \
3503 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3504 *MACRO_list = (JavaThread*)(LIST), \
3505 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3506 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3507 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3508 MACRO_current_p != MACRO_end; \
3509 MACRO_current_p++, \
3510 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3511
3512 // All JavaThreads
3513 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3514
3515 // All NonJavaThreads (i.e., every non-JavaThread in the system).
3516 void Threads::non_java_threads_do(ThreadClosure* tc) {
3517 NoSafepointVerifier nsv(!SafepointSynchronize::is_at_safepoint(), false);
3518 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
3519 tc->do_thread(njti.current());
3520 }
3521 }
3522
3523 // All JavaThreads
3524 void Threads::java_threads_do(ThreadClosure* tc) {
3525 assert_locked_or_safepoint(Threads_lock);
3526 // ALL_JAVA_THREADS iterates through all JavaThreads.
3527 ALL_JAVA_THREADS(p) {
3528 tc->do_thread(p);
3529 }
3530 }
3531
3532 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3533 assert_locked_or_safepoint(Threads_lock);
3534 java_threads_do(tc);
3535 tc->do_thread(VMThread::vm_thread());
3536 }
3537
3538 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3539 void Threads::threads_do(ThreadClosure* tc) {
3540 assert_locked_or_safepoint(Threads_lock);
3541 java_threads_do(tc);
3542 non_java_threads_do(tc);
3543 }
3544
3545 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3546 int cp = Threads::thread_claim_parity();
3547 ALL_JAVA_THREADS(p) {
3548 if (p->claim_oops_do(is_par, cp)) {
3549 tc->do_thread(p);
3550 }
3551 }
3552 VMThread* vmt = VMThread::vm_thread();
3553 if (vmt->claim_oops_do(is_par, cp)) {
3554 tc->do_thread(vmt);
3555 }
3556 }
3557
3558 // The system initialization in the library has three phases.
3559 //
3560 // Phase 1: java.lang.System class initialization
3561 // java.lang.System is a primordial class loaded and initialized
3562 // by the VM early during startup. java.lang.System.<clinit>
3563 // only does registerNatives and keeps the rest of the class
3564 // initialization work later until thread initialization completes.
3565 //
3566 // System.initPhase1 initializes the system properties, the static
3567 // fields in, out, and err. Set up java signal handlers, OS-specific
3568 // system settings, and thread group of the main thread.
3569 static void call_initPhase1(TRAPS) {
3570 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3571 JavaValue result(T_VOID);
3572 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3573 vmSymbols::void_method_signature(), CHECK);
3574 }
3575
3576 // Phase 2. Module system initialization
3577 // This will initialize the module system. Only java.base classes
3578 // can be loaded until phase 2 completes.
3579 //
3580 // Call System.initPhase2 after the compiler initialization and jsr292
3581 // classes get initialized because module initialization runs a lot of java
3582 // code, that for performance reasons, should be compiled. Also, this will
3583 // enable the startup code to use lambda and other language features in this
3584 // phase and onward.
3585 //
3586 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3587 static void call_initPhase2(TRAPS) {
3588 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3589
3590 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3591
3592 JavaValue result(T_INT);
3593 JavaCallArguments args;
3594 args.push_int(DisplayVMOutputToStderr);
3595 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3596 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3597 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3598 if (result.get_jint() != JNI_OK) {
3599 vm_exit_during_initialization(); // no message or exception
3600 }
3601
3602 universe_post_module_init();
3603 }
3604
3605 // Phase 3. final setup - set security manager, system class loader and TCCL
3606 //
3607 // This will instantiate and set the security manager, set the system class
3608 // loader as well as the thread context class loader. The security manager
3609 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3610 // other modules or the application's classpath.
3611 static void call_initPhase3(TRAPS) {
3612 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3613 JavaValue result(T_VOID);
3614 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3615 vmSymbols::void_method_signature(), CHECK);
3616 }
3617
3618 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3619 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3620
3621 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3622 create_vm_init_libraries();
3623 }
3624
3625 initialize_class(vmSymbols::java_lang_String(), CHECK);
3626
3627 // Inject CompactStrings value after the static initializers for String ran.
3628 java_lang_String::set_compact_strings(CompactStrings);
3629
3630 // Initialize java_lang.System (needed before creating the thread)
3631 initialize_class(vmSymbols::java_lang_System(), CHECK);
3632 // The VM creates & returns objects of this class. Make sure it's initialized.
3633 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3634 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3635 Handle thread_group = create_initial_thread_group(CHECK);
3636 Universe::set_main_thread_group(thread_group());
3637 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3638 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3639 main_thread->set_threadObj(thread_object);
3640 // Set thread status to running since main thread has
3641 // been started and running.
3642 java_lang_Thread::set_thread_status(thread_object,
3643 java_lang_Thread::RUNNABLE);
3644
3645 // The VM creates objects of this class.
3646 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3647
3648 // The VM preresolves methods to these classes. Make sure that they get initialized
3649 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3650 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3651
3652 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3653 call_initPhase1(CHECK);
3654
3655 // get the Java runtime name after java.lang.System is initialized
3656 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3657 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3658
3659 // an instance of OutOfMemory exception has been allocated earlier
3660 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3661 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3662 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3663 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3664 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3665 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3666 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3667 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3668 }
3669
3670 void Threads::initialize_jsr292_core_classes(TRAPS) {
3671 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3672
3673 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3674 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3675 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3676 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3677 }
3678
3679 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3680 extern void JDK_Version_init();
3681
3682 // Preinitialize version info.
3683 VM_Version::early_initialize();
3684
3685 // Check version
3686 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3687
3688 // Initialize library-based TLS
3689 ThreadLocalStorage::init();
3690
3691 // Initialize the output stream module
3692 ostream_init();
3693
3694 // Process java launcher properties.
3695 Arguments::process_sun_java_launcher_properties(args);
3696
3697 // Initialize the os module
3698 os::init();
3699
3700 // Record VM creation timing statistics
3701 TraceVmCreationTime create_vm_timer;
3702 create_vm_timer.start();
3703
3704 // Initialize system properties.
3705 Arguments::init_system_properties();
3706
3707 // So that JDK version can be used as a discriminator when parsing arguments
3708 JDK_Version_init();
3709
3710 // Update/Initialize System properties after JDK version number is known
3711 Arguments::init_version_specific_system_properties();
3712
3713 // Make sure to initialize log configuration *before* parsing arguments
3714 LogConfiguration::initialize(create_vm_timer.begin_time());
3715
3716 // Parse arguments
3717 // Note: this internally calls os::init_container_support()
3718 jint parse_result = Arguments::parse(args);
3719 if (parse_result != JNI_OK) return parse_result;
3720
3721 os::init_before_ergo();
3722
3723 jint ergo_result = Arguments::apply_ergo();
3724 if (ergo_result != JNI_OK) return ergo_result;
3725
3726 // Final check of all ranges after ergonomics which may change values.
3727 if (!JVMFlagRangeList::check_ranges()) {
3728 return JNI_EINVAL;
3729 }
3730
3731 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3732 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo);
3733 if (!constraint_result) {
3734 return JNI_EINVAL;
3735 }
3736
3737 JVMFlagWriteableList::mark_startup();
3738
3739 if (PauseAtStartup) {
3740 os::pause();
3741 }
3742
3743 HOTSPOT_VM_INIT_BEGIN();
3744
3745 // Timing (must come after argument parsing)
3746 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3747
3748 // Initialize the os module after parsing the args
3749 jint os_init_2_result = os::init_2();
3750 if (os_init_2_result != JNI_OK) return os_init_2_result;
3751
3752 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3753 // Initialize assert poison page mechanism.
3754 if (ShowRegistersOnAssert) {
3755 initialize_assert_poison();
3756 }
3757 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3758
3759 SafepointMechanism::initialize();
3760
3761 jint adjust_after_os_result = Arguments::adjust_after_os();
3762 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3763
3764 // Initialize output stream logging
3765 ostream_init_log();
3766
3767 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3768 // Must be before create_vm_init_agents()
3769 if (Arguments::init_libraries_at_startup()) {
3770 convert_vm_init_libraries_to_agents();
3771 }
3772
3773 // Launch -agentlib/-agentpath and converted -Xrun agents
3774 if (Arguments::init_agents_at_startup()) {
3775 create_vm_init_agents();
3776 }
3777
3778 // Initialize Threads state
3779 _thread_list = NULL;
3780 _number_of_threads = 0;
3781 _number_of_non_daemon_threads = 0;
3782
3783 // Initialize global data structures and create system classes in heap
3784 vm_init_globals();
3785
3786 #if INCLUDE_JVMCI
3787 if (JVMCICounterSize > 0) {
3788 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3789 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3790 } else {
3791 JavaThread::_jvmci_old_thread_counters = NULL;
3792 }
3793 #endif // INCLUDE_JVMCI
3794
3795 // Attach the main thread to this os thread
3796 JavaThread* main_thread = new JavaThread();
3797 main_thread->set_thread_state(_thread_in_vm);
3798 main_thread->initialize_thread_current();
3799 // must do this before set_active_handles
3800 main_thread->record_stack_base_and_size();
3801 main_thread->register_thread_stack_with_NMT();
3802 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3803
3804 if (!main_thread->set_as_starting_thread()) {
3805 vm_shutdown_during_initialization(
3806 "Failed necessary internal allocation. Out of swap space");
3807 main_thread->smr_delete();
3808 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3809 return JNI_ENOMEM;
3810 }
3811
3812 // Enable guard page *after* os::create_main_thread(), otherwise it would
3813 // crash Linux VM, see notes in os_linux.cpp.
3814 main_thread->create_stack_guard_pages();
3815
3816 // Initialize Java-Level synchronization subsystem
3817 ObjectMonitor::Initialize();
3818
3819 // Initialize global modules
3820 jint status = init_globals();
3821 if (status != JNI_OK) {
3822 main_thread->smr_delete();
3823 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3824 return status;
3825 }
3826
3827 JFR_ONLY(Jfr::on_vm_init();)
3828
3829 // Should be done after the heap is fully created
3830 main_thread->cache_global_variables();
3831
3832 HandleMark hm;
3833
3834 { MutexLocker mu(Threads_lock);
3835 Threads::add(main_thread);
3836 }
3837
3838 // Any JVMTI raw monitors entered in onload will transition into
3839 // real raw monitor. VM is setup enough here for raw monitor enter.
3840 JvmtiExport::transition_pending_onload_raw_monitors();
3841
3842 // Create the VMThread
3843 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3844
3845 VMThread::create();
3846 Thread* vmthread = VMThread::vm_thread();
3847
3848 if (!os::create_thread(vmthread, os::vm_thread)) {
3849 vm_exit_during_initialization("Cannot create VM thread. "
3850 "Out of system resources.");
3851 }
3852
3853 // Wait for the VM thread to become ready, and VMThread::run to initialize
3854 // Monitors can have spurious returns, must always check another state flag
3855 {
3856 MutexLocker ml(Notify_lock);
3857 os::start_thread(vmthread);
3858 while (vmthread->active_handles() == NULL) {
3859 Notify_lock->wait();
3860 }
3861 }
3862 }
3863
3864 assert(Universe::is_fully_initialized(), "not initialized");
3865 if (VerifyDuringStartup) {
3866 // Make sure we're starting with a clean slate.
3867 VM_Verify verify_op;
3868 VMThread::execute(&verify_op);
3869 }
3870
3871 // We need this to update the java.vm.info property in case any flags used
3872 // to initially define it have been changed. This is needed for both CDS and
3873 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info
3874 // is initially computed. See Abstract_VM_Version::vm_info_string().
3875 // This update must happen before we initialize the java classes, but
3876 // after any initialization logic that might modify the flags.
3877 Arguments::update_vm_info_property(VM_Version::vm_info_string());
3878
3879 Thread* THREAD = Thread::current();
3880
3881 // Always call even when there are not JVMTI environments yet, since environments
3882 // may be attached late and JVMTI must track phases of VM execution
3883 JvmtiExport::enter_early_start_phase();
3884
3885 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3886 JvmtiExport::post_early_vm_start();
3887
3888 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3889
3890 quicken_jni_functions();
3891
3892 // No more stub generation allowed after that point.
3893 StubCodeDesc::freeze();
3894
3895 // Set flag that basic initialization has completed. Used by exceptions and various
3896 // debug stuff, that does not work until all basic classes have been initialized.
3897 set_init_completed();
3898
3899 LogConfiguration::post_initialize();
3900 Metaspace::post_initialize();
3901
3902 HOTSPOT_VM_INIT_END();
3903
3904 // record VM initialization completion time
3905 #if INCLUDE_MANAGEMENT
3906 Management::record_vm_init_completed();
3907 #endif // INCLUDE_MANAGEMENT
3908
3909 // Signal Dispatcher needs to be started before VMInit event is posted
3910 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3911
3912 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3913 if (!DisableAttachMechanism) {
3914 AttachListener::vm_start();
3915 if (StartAttachListener || AttachListener::init_at_startup()) {
3916 AttachListener::init();
3917 }
3918 }
3919
3920 // Launch -Xrun agents
3921 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3922 // back-end can launch with -Xdebug -Xrunjdwp.
3923 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3924 create_vm_init_libraries();
3925 }
3926
3927 if (CleanChunkPoolAsync) {
3928 Chunk::start_chunk_pool_cleaner_task();
3929 }
3930
3931 // initialize compiler(s)
3932 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3933 #if INCLUDE_JVMCI
3934 bool force_JVMCI_intialization = false;
3935 if (EnableJVMCI) {
3936 // Initialize JVMCI eagerly when it is explicitly requested.
3937 // Or when JVMCIPrintProperties is enabled.
3938 // The JVMCI Java initialization code will read this flag and
3939 // do the printing if it's set.
3940 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties;
3941
3942 if (!force_JVMCI_intialization) {
3943 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3944 // compilations via JVMCI will not actually block until JVMCI is initialized.
3945 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3946 }
3947 }
3948 #endif
3949 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
3950 // Postpone completion of compiler initialization to after JVMCI
3951 // is initialized to avoid timeouts of blocking compilations.
3952 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
3953 CompileBroker::compilation_init_phase2();
3954 }
3955 #endif
3956
3957 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3958 // It is done after compilers are initialized, because otherwise compilations of
3959 // signature polymorphic MH intrinsics can be missed
3960 // (see SystemDictionary::find_method_handle_intrinsic).
3961 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3962
3963 // This will initialize the module system. Only java.base classes can be
3964 // loaded until phase 2 completes
3965 call_initPhase2(CHECK_JNI_ERR);
3966
3967 // Always call even when there are not JVMTI environments yet, since environments
3968 // may be attached late and JVMTI must track phases of VM execution
3969 JvmtiExport::enter_start_phase();
3970
3971 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3972 JvmtiExport::post_vm_start();
3973
3974 // Final system initialization including security manager and system class loader
3975 call_initPhase3(CHECK_JNI_ERR);
3976
3977 // cache the system and platform class loaders
3978 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
3979
3980 #if INCLUDE_CDS
3981 if (DumpSharedSpaces) {
3982 // capture the module path info from the ModuleEntryTable
3983 ClassLoader::initialize_module_path(THREAD);
3984 }
3985 #endif
3986
3987 #if INCLUDE_JVMCI
3988 if (force_JVMCI_intialization) {
3989 JVMCIRuntime::force_initialization(CHECK_JNI_ERR);
3990 CompileBroker::compilation_init_phase2();
3991 }
3992 #endif
3993
3994 // Always call even when there are not JVMTI environments yet, since environments
3995 // may be attached late and JVMTI must track phases of VM execution
3996 JvmtiExport::enter_live_phase();
3997
3998 // Make perfmemory accessible
3999 PerfMemory::set_accessible(true);
4000
4001 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
4002 JvmtiExport::post_vm_initialized();
4003
4004 JFR_ONLY(Jfr::on_vm_start();)
4005
4006 #if INCLUDE_MANAGEMENT
4007 Management::initialize(THREAD);
4008
4009 if (HAS_PENDING_EXCEPTION) {
4010 // management agent fails to start possibly due to
4011 // configuration problem and is responsible for printing
4012 // stack trace if appropriate. Simply exit VM.
4013 vm_exit(1);
4014 }
4015 #endif // INCLUDE_MANAGEMENT
4016
4017 if (MemProfiling) MemProfiler::engage();
4018 StatSampler::engage();
4019 if (CheckJNICalls) JniPeriodicChecker::engage();
4020
4021 BiasedLocking::init();
4022
4023 #if INCLUDE_RTM_OPT
4024 RTMLockingCounters::init();
4025 #endif
4026
4027 if (JDK_Version::current().post_vm_init_hook_enabled()) {
4028 call_postVMInitHook(THREAD);
4029 // The Java side of PostVMInitHook.run must deal with all
4030 // exceptions and provide means of diagnosis.
4031 if (HAS_PENDING_EXCEPTION) {
4032 CLEAR_PENDING_EXCEPTION;
4033 }
4034 }
4035
4036 {
4037 MutexLocker ml(PeriodicTask_lock);
4038 // Make sure the WatcherThread can be started by WatcherThread::start()
4039 // or by dynamic enrollment.
4040 WatcherThread::make_startable();
4041 // Start up the WatcherThread if there are any periodic tasks
4042 // NOTE: All PeriodicTasks should be registered by now. If they
4043 // aren't, late joiners might appear to start slowly (we might
4044 // take a while to process their first tick).
4045 if (PeriodicTask::num_tasks() > 0) {
4046 WatcherThread::start();
4047 }
4048 }
4049
4050 create_vm_timer.end();
4051 #ifdef ASSERT
4052 _vm_complete = true;
4053 #endif
4054
4055 if (DumpSharedSpaces) {
4056 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
4057 ShouldNotReachHere();
4058 }
4059
4060 return JNI_OK;
4061 }
4062
4063 // type for the Agent_OnLoad and JVM_OnLoad entry points
4064 extern "C" {
4065 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
4066 }
4067 // Find a command line agent library and return its entry point for
4068 // -agentlib: -agentpath: -Xrun
4069 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
4070 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
4071 const char *on_load_symbols[],
4072 size_t num_symbol_entries) {
4073 OnLoadEntry_t on_load_entry = NULL;
4074 void *library = NULL;
4075
4076 if (!agent->valid()) {
4077 char buffer[JVM_MAXPATHLEN];
4078 char ebuf[1024] = "";
4079 const char *name = agent->name();
4080 const char *msg = "Could not find agent library ";
4081
4082 // First check to see if agent is statically linked into executable
4083 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
4084 library = agent->os_lib();
4085 } else if (agent->is_absolute_path()) {
4086 library = os::dll_load(name, ebuf, sizeof ebuf);
4087 if (library == NULL) {
4088 const char *sub_msg = " in absolute path, with error: ";
4089 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4090 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4091 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4092 // If we can't find the agent, exit.
4093 vm_exit_during_initialization(buf, NULL);
4094 FREE_C_HEAP_ARRAY(char, buf);
4095 }
4096 } else {
4097 // Try to load the agent from the standard dll directory
4098 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4099 name)) {
4100 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4101 }
4102 if (library == NULL) { // Try the library path directory.
4103 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4104 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4105 }
4106 if (library == NULL) {
4107 const char *sub_msg = " on the library path, with error: ";
4108 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4109
4110 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4111 strlen(ebuf) + strlen(sub_msg2) + 1;
4112 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4113 if (!agent->is_instrument_lib()) {
4114 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4115 } else {
4116 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4117 }
4118 // If we can't find the agent, exit.
4119 vm_exit_during_initialization(buf, NULL);
4120 FREE_C_HEAP_ARRAY(char, buf);
4121 }
4122 }
4123 }
4124 agent->set_os_lib(library);
4125 agent->set_valid();
4126 }
4127
4128 // Find the OnLoad function.
4129 on_load_entry =
4130 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4131 false,
4132 on_load_symbols,
4133 num_symbol_entries));
4134 return on_load_entry;
4135 }
4136
4137 // Find the JVM_OnLoad entry point
4138 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4139 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4140 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4141 }
4142
4143 // Find the Agent_OnLoad entry point
4144 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4145 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4146 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4147 }
4148
4149 // For backwards compatibility with -Xrun
4150 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4151 // treated like -agentpath:
4152 // Must be called before agent libraries are created
4153 void Threads::convert_vm_init_libraries_to_agents() {
4154 AgentLibrary* agent;
4155 AgentLibrary* next;
4156
4157 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4158 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4159 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4160
4161 // If there is an JVM_OnLoad function it will get called later,
4162 // otherwise see if there is an Agent_OnLoad
4163 if (on_load_entry == NULL) {
4164 on_load_entry = lookup_agent_on_load(agent);
4165 if (on_load_entry != NULL) {
4166 // switch it to the agent list -- so that Agent_OnLoad will be called,
4167 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4168 Arguments::convert_library_to_agent(agent);
4169 } else {
4170 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4171 }
4172 }
4173 }
4174 }
4175
4176 // Create agents for -agentlib: -agentpath: and converted -Xrun
4177 // Invokes Agent_OnLoad
4178 // Called very early -- before JavaThreads exist
4179 void Threads::create_vm_init_agents() {
4180 extern struct JavaVM_ main_vm;
4181 AgentLibrary* agent;
4182
4183 JvmtiExport::enter_onload_phase();
4184
4185 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4186 // CDS dumping does not support native JVMTI agent.
4187 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
4188 if (DumpSharedSpaces) {
4189 if(!agent->is_instrument_lib()) {
4190 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
4191 } else if (!AllowArchivingWithJavaAgent) {
4192 vm_exit_during_cds_dumping(
4193 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
4194 }
4195 }
4196
4197 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4198
4199 if (on_load_entry != NULL) {
4200 // Invoke the Agent_OnLoad function
4201 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4202 if (err != JNI_OK) {
4203 vm_exit_during_initialization("agent library failed to init", agent->name());
4204 }
4205 } else {
4206 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4207 }
4208 }
4209
4210 JvmtiExport::enter_primordial_phase();
4211 }
4212
4213 extern "C" {
4214 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4215 }
4216
4217 void Threads::shutdown_vm_agents() {
4218 // Send any Agent_OnUnload notifications
4219 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4220 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4221 extern struct JavaVM_ main_vm;
4222 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4223
4224 // Find the Agent_OnUnload function.
4225 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4226 os::find_agent_function(agent,
4227 false,
4228 on_unload_symbols,
4229 num_symbol_entries));
4230
4231 // Invoke the Agent_OnUnload function
4232 if (unload_entry != NULL) {
4233 JavaThread* thread = JavaThread::current();
4234 ThreadToNativeFromVM ttn(thread);
4235 HandleMark hm(thread);
4236 (*unload_entry)(&main_vm);
4237 }
4238 }
4239 }
4240
4241 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4242 // Invokes JVM_OnLoad
4243 void Threads::create_vm_init_libraries() {
4244 extern struct JavaVM_ main_vm;
4245 AgentLibrary* agent;
4246
4247 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4248 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4249
4250 if (on_load_entry != NULL) {
4251 // Invoke the JVM_OnLoad function
4252 JavaThread* thread = JavaThread::current();
4253 ThreadToNativeFromVM ttn(thread);
4254 HandleMark hm(thread);
4255 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4256 if (err != JNI_OK) {
4257 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4258 }
4259 } else {
4260 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4261 }
4262 }
4263 }
4264
4265
4266 // Last thread running calls java.lang.Shutdown.shutdown()
4267 void JavaThread::invoke_shutdown_hooks() {
4268 HandleMark hm(this);
4269
4270 // We could get here with a pending exception, if so clear it now.
4271 if (this->has_pending_exception()) {
4272 this->clear_pending_exception();
4273 }
4274
4275 EXCEPTION_MARK;
4276 Klass* shutdown_klass =
4277 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4278 THREAD);
4279 if (shutdown_klass != NULL) {
4280 // SystemDictionary::resolve_or_null will return null if there was
4281 // an exception. If we cannot load the Shutdown class, just don't
4282 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4283 // won't be run. Note that if a shutdown hook was registered,
4284 // the Shutdown class would have already been loaded
4285 // (Runtime.addShutdownHook will load it).
4286 JavaValue result(T_VOID);
4287 JavaCalls::call_static(&result,
4288 shutdown_klass,
4289 vmSymbols::shutdown_method_name(),
4290 vmSymbols::void_method_signature(),
4291 THREAD);
4292 }
4293 CLEAR_PENDING_EXCEPTION;
4294 }
4295
4296 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4297 // the program falls off the end of main(). Another VM exit path is through
4298 // vm_exit() when the program calls System.exit() to return a value or when
4299 // there is a serious error in VM. The two shutdown paths are not exactly
4300 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4301 // and VM_Exit op at VM level.
4302 //
4303 // Shutdown sequence:
4304 // + Shutdown native memory tracking if it is on
4305 // + Wait until we are the last non-daemon thread to execute
4306 // <-- every thing is still working at this moment -->
4307 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4308 // shutdown hooks
4309 // + Call before_exit(), prepare for VM exit
4310 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4311 // currently the only user of this mechanism is File.deleteOnExit())
4312 // > stop StatSampler, watcher thread, CMS threads,
4313 // post thread end and vm death events to JVMTI,
4314 // stop signal thread
4315 // + Call JavaThread::exit(), it will:
4316 // > release JNI handle blocks, remove stack guard pages
4317 // > remove this thread from Threads list
4318 // <-- no more Java code from this thread after this point -->
4319 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4320 // the compiler threads at safepoint
4321 // <-- do not use anything that could get blocked by Safepoint -->
4322 // + Disable tracing at JNI/JVM barriers
4323 // + Set _vm_exited flag for threads that are still running native code
4324 // + Call exit_globals()
4325 // > deletes tty
4326 // > deletes PerfMemory resources
4327 // + Delete this thread
4328 // + Return to caller
4329
4330 bool Threads::destroy_vm() {
4331 JavaThread* thread = JavaThread::current();
4332
4333 #ifdef ASSERT
4334 _vm_complete = false;
4335 #endif
4336 // Wait until we are the last non-daemon thread to execute
4337 { MutexLocker nu(Threads_lock);
4338 while (Threads::number_of_non_daemon_threads() > 1)
4339 // This wait should make safepoint checks, wait without a timeout,
4340 // and wait as a suspend-equivalent condition.
4341 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4342 Mutex::_as_suspend_equivalent_flag);
4343 }
4344
4345 EventShutdown e;
4346 if (e.should_commit()) {
4347 e.set_reason("No remaining non-daemon Java threads");
4348 e.commit();
4349 }
4350
4351 // Hang forever on exit if we are reporting an error.
4352 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4353 os::infinite_sleep();
4354 }
4355 os::wait_for_keypress_at_exit();
4356
4357 // run Java level shutdown hooks
4358 thread->invoke_shutdown_hooks();
4359
4360 before_exit(thread);
4361
4362 thread->exit(true);
4363
4364 // Stop VM thread.
4365 {
4366 // 4945125 The vm thread comes to a safepoint during exit.
4367 // GC vm_operations can get caught at the safepoint, and the
4368 // heap is unparseable if they are caught. Grab the Heap_lock
4369 // to prevent this. The GC vm_operations will not be able to
4370 // queue until after the vm thread is dead. After this point,
4371 // we'll never emerge out of the safepoint before the VM exits.
4372
4373 MutexLockerEx ml(Heap_lock, Mutex::_no_safepoint_check_flag);
4374
4375 VMThread::wait_for_vm_thread_exit();
4376 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4377 VMThread::destroy();
4378 }
4379
4380 // Now, all Java threads are gone except daemon threads. Daemon threads
4381 // running Java code or in VM are stopped by the Safepoint. However,
4382 // daemon threads executing native code are still running. But they
4383 // will be stopped at native=>Java/VM barriers. Note that we can't
4384 // simply kill or suspend them, as it is inherently deadlock-prone.
4385
4386 VM_Exit::set_vm_exited();
4387
4388 // Clean up ideal graph printers after the VMThread has started
4389 // the final safepoint which will block all the Compiler threads.
4390 // Note that this Thread has already logically exited so the
4391 // clean_up() function's use of a JavaThreadIteratorWithHandle
4392 // would be a problem except set_vm_exited() has remembered the
4393 // shutdown thread which is granted a policy exception.
4394 #if defined(COMPILER2) && !defined(PRODUCT)
4395 IdealGraphPrinter::clean_up();
4396 #endif
4397
4398 notify_vm_shutdown();
4399
4400 // exit_globals() will delete tty
4401 exit_globals();
4402
4403 // We are after VM_Exit::set_vm_exited() so we can't call
4404 // thread->smr_delete() or we will block on the Threads_lock.
4405 // Deleting the shutdown thread here is safe because another
4406 // JavaThread cannot have an active ThreadsListHandle for
4407 // this JavaThread.
4408 delete thread;
4409
4410 #if INCLUDE_JVMCI
4411 if (JVMCICounterSize > 0) {
4412 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4413 }
4414 #endif
4415
4416 LogConfiguration::finalize();
4417
4418 return true;
4419 }
4420
4421
4422 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4423 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4424 return is_supported_jni_version(version);
4425 }
4426
4427
4428 jboolean Threads::is_supported_jni_version(jint version) {
4429 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4430 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4431 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4432 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4433 if (version == JNI_VERSION_9) return JNI_TRUE;
4434 if (version == JNI_VERSION_10) return JNI_TRUE;
4435 return JNI_FALSE;
4436 }
4437
4438
4439 void Threads::add(JavaThread* p, bool force_daemon) {
4440 // The threads lock must be owned at this point
4441 assert(Threads_lock->owned_by_self(), "must have threads lock");
4442
4443 BarrierSet::barrier_set()->on_thread_attach(p);
4444
4445 p->set_next(_thread_list);
4446 _thread_list = p;
4447
4448 // Once a JavaThread is added to the Threads list, smr_delete() has
4449 // to be used to delete it. Otherwise we can just delete it directly.
4450 p->set_on_thread_list();
4451
4452 _number_of_threads++;
4453 oop threadObj = p->threadObj();
4454 bool daemon = true;
4455 // Bootstrapping problem: threadObj can be null for initial
4456 // JavaThread (or for threads attached via JNI)
4457 if ((!force_daemon) && !is_daemon((threadObj))) {
4458 _number_of_non_daemon_threads++;
4459 daemon = false;
4460 }
4461
4462 ThreadService::add_thread(p, daemon);
4463
4464 // Maintain fast thread list
4465 ThreadsSMRSupport::add_thread(p);
4466
4467 // Possible GC point.
4468 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4469 }
4470
4471 void Threads::remove(JavaThread* p) {
4472
4473 // Reclaim the objectmonitors from the omInUseList and omFreeList of the moribund thread.
4474 ObjectSynchronizer::omFlush(p);
4475
4476 // Extra scope needed for Thread_lock, so we can check
4477 // that we do not remove thread without safepoint code notice
4478 { MutexLocker ml(Threads_lock);
4479
4480 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4481
4482 // Maintain fast thread list
4483 ThreadsSMRSupport::remove_thread(p);
4484
4485 JavaThread* current = _thread_list;
4486 JavaThread* prev = NULL;
4487
4488 while (current != p) {
4489 prev = current;
4490 current = current->next();
4491 }
4492
4493 if (prev) {
4494 prev->set_next(current->next());
4495 } else {
4496 _thread_list = p->next();
4497 }
4498
4499 _number_of_threads--;
4500 oop threadObj = p->threadObj();
4501 bool daemon = true;
4502 if (!is_daemon(threadObj)) {
4503 _number_of_non_daemon_threads--;
4504 daemon = false;
4505
4506 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4507 // on destroy_vm will wake up.
4508 if (number_of_non_daemon_threads() == 1) {
4509 Threads_lock->notify_all();
4510 }
4511 }
4512 ThreadService::remove_thread(p, daemon);
4513
4514 // Make sure that safepoint code disregard this thread. This is needed since
4515 // the thread might mess around with locks after this point. This can cause it
4516 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4517 // of this thread since it is removed from the queue.
4518 p->set_terminated_value();
4519 } // unlock Threads_lock
4520
4521 // Since Events::log uses a lock, we grab it outside the Threads_lock
4522 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4523 }
4524
4525 // Operations on the Threads list for GC. These are not explicitly locked,
4526 // but the garbage collector must provide a safe context for them to run.
4527 // In particular, these things should never be called when the Threads_lock
4528 // is held by some other thread. (Note: the Safepoint abstraction also
4529 // uses the Threads_lock to guarantee this property. It also makes sure that
4530 // all threads gets blocked when exiting or starting).
4531
4532 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4533 ALL_JAVA_THREADS(p) {
4534 p->oops_do(f, cf);
4535 }
4536 VMThread::vm_thread()->oops_do(f, cf);
4537 }
4538
4539 void Threads::change_thread_claim_parity() {
4540 // Set the new claim parity.
4541 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4542 "Not in range.");
4543 _thread_claim_parity++;
4544 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4545 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4546 "Not in range.");
4547 }
4548
4549 #ifdef ASSERT
4550 void Threads::assert_all_threads_claimed() {
4551 ALL_JAVA_THREADS(p) {
4552 const int thread_parity = p->oops_do_parity();
4553 assert((thread_parity == _thread_claim_parity),
4554 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4555 }
4556 VMThread* vmt = VMThread::vm_thread();
4557 const int thread_parity = vmt->oops_do_parity();
4558 assert((thread_parity == _thread_claim_parity),
4559 "VMThread " PTR_FORMAT " has incorrect parity %d != %d", p2i(vmt), thread_parity, _thread_claim_parity);
4560 }
4561 #endif // ASSERT
4562
4563 class ParallelOopsDoThreadClosure : public ThreadClosure {
4564 private:
4565 OopClosure* _f;
4566 CodeBlobClosure* _cf;
4567 public:
4568 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4569 void do_thread(Thread* t) {
4570 t->oops_do(_f, _cf);
4571 }
4572 };
4573
4574 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4575 ParallelOopsDoThreadClosure tc(f, cf);
4576 possibly_parallel_threads_do(is_par, &tc);
4577 }
4578
4579 void Threads::nmethods_do(CodeBlobClosure* cf) {
4580 ALL_JAVA_THREADS(p) {
4581 // This is used by the code cache sweeper to mark nmethods that are active
4582 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4583 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4584 if(!p->is_Code_cache_sweeper_thread()) {
4585 p->nmethods_do(cf);
4586 }
4587 }
4588 }
4589
4590 void Threads::metadata_do(void f(Metadata*)) {
4591 ALL_JAVA_THREADS(p) {
4592 p->metadata_do(f);
4593 }
4594 }
4595
4596 class ThreadHandlesClosure : public ThreadClosure {
4597 void (*_f)(Metadata*);
4598 public:
4599 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4600 virtual void do_thread(Thread* thread) {
4601 thread->metadata_handles_do(_f);
4602 }
4603 };
4604
4605 void Threads::metadata_handles_do(void f(Metadata*)) {
4606 // Only walk the Handles in Thread.
4607 ThreadHandlesClosure handles_closure(f);
4608 threads_do(&handles_closure);
4609 }
4610
4611 void Threads::deoptimized_wrt_marked_nmethods() {
4612 ALL_JAVA_THREADS(p) {
4613 p->deoptimized_wrt_marked_nmethods();
4614 }
4615 }
4616
4617
4618 // Get count Java threads that are waiting to enter the specified monitor.
4619 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4620 int count,
4621 address monitor) {
4622 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4623
4624 int i = 0;
4625 DO_JAVA_THREADS(t_list, p) {
4626 if (!p->can_call_java()) continue;
4627
4628 address pending = (address)p->current_pending_monitor();
4629 if (pending == monitor) { // found a match
4630 if (i < count) result->append(p); // save the first count matches
4631 i++;
4632 }
4633 }
4634
4635 return result;
4636 }
4637
4638
4639 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4640 address owner) {
4641 // NULL owner means not locked so we can skip the search
4642 if (owner == NULL) return NULL;
4643
4644 DO_JAVA_THREADS(t_list, p) {
4645 // first, see if owner is the address of a Java thread
4646 if (owner == (address)p) return p;
4647 }
4648
4649 // Cannot assert on lack of success here since this function may be
4650 // used by code that is trying to report useful problem information
4651 // like deadlock detection.
4652 if (UseHeavyMonitors) return NULL;
4653
4654 // If we didn't find a matching Java thread and we didn't force use of
4655 // heavyweight monitors, then the owner is the stack address of the
4656 // Lock Word in the owning Java thread's stack.
4657 //
4658 JavaThread* the_owner = NULL;
4659 DO_JAVA_THREADS(t_list, q) {
4660 if (q->is_lock_owned(owner)) {
4661 the_owner = q;
4662 break;
4663 }
4664 }
4665
4666 // cannot assert on lack of success here; see above comment
4667 return the_owner;
4668 }
4669
4670 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4671 void Threads::print_on(outputStream* st, bool print_stacks,
4672 bool internal_format, bool print_concurrent_locks,
4673 bool print_extended_info) {
4674 char buf[32];
4675 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4676
4677 st->print_cr("Full thread dump %s (%s %s):",
4678 VM_Version::vm_name(),
4679 VM_Version::vm_release(),
4680 VM_Version::vm_info_string());
4681 st->cr();
4682
4683 #if INCLUDE_SERVICES
4684 // Dump concurrent locks
4685 ConcurrentLocksDump concurrent_locks;
4686 if (print_concurrent_locks) {
4687 concurrent_locks.dump_at_safepoint();
4688 }
4689 #endif // INCLUDE_SERVICES
4690
4691 ThreadsSMRSupport::print_info_on(st);
4692 st->cr();
4693
4694 ALL_JAVA_THREADS(p) {
4695 ResourceMark rm;
4696 p->print_on(st, print_extended_info);
4697 if (print_stacks) {
4698 if (internal_format) {
4699 p->trace_stack();
4700 } else {
4701 p->print_stack_on(st);
4702 }
4703 }
4704 st->cr();
4705 #if INCLUDE_SERVICES
4706 if (print_concurrent_locks) {
4707 concurrent_locks.print_locks_on(p, st);
4708 }
4709 #endif // INCLUDE_SERVICES
4710 }
4711
4712 VMThread::vm_thread()->print_on(st);
4713 st->cr();
4714 Universe::heap()->print_gc_threads_on(st);
4715 WatcherThread* wt = WatcherThread::watcher_thread();
4716 if (wt != NULL) {
4717 wt->print_on(st);
4718 st->cr();
4719 }
4720
4721 st->flush();
4722 }
4723
4724 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4725 int buflen, bool* found_current) {
4726 if (this_thread != NULL) {
4727 bool is_current = (current == this_thread);
4728 *found_current = *found_current || is_current;
4729 st->print("%s", is_current ? "=>" : " ");
4730
4731 st->print(PTR_FORMAT, p2i(this_thread));
4732 st->print(" ");
4733 this_thread->print_on_error(st, buf, buflen);
4734 st->cr();
4735 }
4736 }
4737
4738 class PrintOnErrorClosure : public ThreadClosure {
4739 outputStream* _st;
4740 Thread* _current;
4741 char* _buf;
4742 int _buflen;
4743 bool* _found_current;
4744 public:
4745 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4746 int buflen, bool* found_current) :
4747 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4748
4749 virtual void do_thread(Thread* thread) {
4750 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4751 }
4752 };
4753
4754 // Threads::print_on_error() is called by fatal error handler. It's possible
4755 // that VM is not at safepoint and/or current thread is inside signal handler.
4756 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4757 // memory (even in resource area), it might deadlock the error handler.
4758 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4759 int buflen) {
4760 ThreadsSMRSupport::print_info_on(st);
4761 st->cr();
4762
4763 bool found_current = false;
4764 st->print_cr("Java Threads: ( => current thread )");
4765 ALL_JAVA_THREADS(thread) {
4766 print_on_error(thread, st, current, buf, buflen, &found_current);
4767 }
4768 st->cr();
4769
4770 st->print_cr("Other Threads:");
4771 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4772 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4773
4774 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4775 Universe::heap()->gc_threads_do(&print_closure);
4776
4777 if (!found_current) {
4778 st->cr();
4779 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4780 current->print_on_error(st, buf, buflen);
4781 st->cr();
4782 }
4783 st->cr();
4784
4785 st->print_cr("Threads with active compile tasks:");
4786 print_threads_compiling(st, buf, buflen);
4787 }
4788
4789 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
4790 ALL_JAVA_THREADS(thread) {
4791 if (thread->is_Compiler_thread()) {
4792 CompilerThread* ct = (CompilerThread*) thread;
4793
4794 // Keep task in local variable for NULL check.
4795 // ct->_task might be set to NULL by concurring compiler thread
4796 // because it completed the compilation. The task is never freed,
4797 // though, just returned to a free list.
4798 CompileTask* task = ct->task();
4799 if (task != NULL) {
4800 thread->print_name_on_error(st, buf, buflen);
4801 st->print(" ");
4802 task->print(st, NULL, short_form, true);
4803 }
4804 }
4805 }
4806 }
4807
4808
4809 // Internal SpinLock and Mutex
4810 // Based on ParkEvent
4811
4812 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4813 //
4814 // We employ SpinLocks _only for low-contention, fixed-length
4815 // short-duration critical sections where we're concerned
4816 // about native mutex_t or HotSpot Mutex:: latency.
4817 // The mux construct provides a spin-then-block mutual exclusion
4818 // mechanism.
4819 //
4820 // Testing has shown that contention on the ListLock guarding gFreeList
4821 // is common. If we implement ListLock as a simple SpinLock it's common
4822 // for the JVM to devolve to yielding with little progress. This is true
4823 // despite the fact that the critical sections protected by ListLock are
4824 // extremely short.
4825 //
4826 // TODO-FIXME: ListLock should be of type SpinLock.
4827 // We should make this a 1st-class type, integrated into the lock
4828 // hierarchy as leaf-locks. Critically, the SpinLock structure
4829 // should have sufficient padding to avoid false-sharing and excessive
4830 // cache-coherency traffic.
4831
4832
4833 typedef volatile int SpinLockT;
4834
4835 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4836 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4837 return; // normal fast-path return
4838 }
4839
4840 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4841 int ctr = 0;
4842 int Yields = 0;
4843 for (;;) {
4844 while (*adr != 0) {
4845 ++ctr;
4846 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4847 if (Yields > 5) {
4848 os::naked_short_sleep(1);
4849 } else {
4850 os::naked_yield();
4851 ++Yields;
4852 }
4853 } else {
4854 SpinPause();
4855 }
4856 }
4857 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4858 }
4859 }
4860
4861 void Thread::SpinRelease(volatile int * adr) {
4862 assert(*adr != 0, "invariant");
4863 OrderAccess::fence(); // guarantee at least release consistency.
4864 // Roach-motel semantics.
4865 // It's safe if subsequent LDs and STs float "up" into the critical section,
4866 // but prior LDs and STs within the critical section can't be allowed
4867 // to reorder or float past the ST that releases the lock.
4868 // Loads and stores in the critical section - which appear in program
4869 // order before the store that releases the lock - must also appear
4870 // before the store that releases the lock in memory visibility order.
4871 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4872 // the ST of 0 into the lock-word which releases the lock, so fence
4873 // more than covers this on all platforms.
4874 *adr = 0;
4875 }
4876
4877 // muxAcquire and muxRelease:
4878 //
4879 // * muxAcquire and muxRelease support a single-word lock-word construct.
4880 // The LSB of the word is set IFF the lock is held.
4881 // The remainder of the word points to the head of a singly-linked list
4882 // of threads blocked on the lock.
4883 //
4884 // * The current implementation of muxAcquire-muxRelease uses its own
4885 // dedicated Thread._MuxEvent instance. If we're interested in
4886 // minimizing the peak number of extant ParkEvent instances then
4887 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4888 // as certain invariants were satisfied. Specifically, care would need
4889 // to be taken with regards to consuming unpark() "permits".
4890 // A safe rule of thumb is that a thread would never call muxAcquire()
4891 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4892 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4893 // consume an unpark() permit intended for monitorenter, for instance.
4894 // One way around this would be to widen the restricted-range semaphore
4895 // implemented in park(). Another alternative would be to provide
4896 // multiple instances of the PlatformEvent() for each thread. One
4897 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4898 //
4899 // * Usage:
4900 // -- Only as leaf locks
4901 // -- for short-term locking only as muxAcquire does not perform
4902 // thread state transitions.
4903 //
4904 // Alternatives:
4905 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4906 // but with parking or spin-then-park instead of pure spinning.
4907 // * Use Taura-Oyama-Yonenzawa locks.
4908 // * It's possible to construct a 1-0 lock if we encode the lockword as
4909 // (List,LockByte). Acquire will CAS the full lockword while Release
4910 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4911 // acquiring threads use timers (ParkTimed) to detect and recover from
4912 // the stranding window. Thread/Node structures must be aligned on 256-byte
4913 // boundaries by using placement-new.
4914 // * Augment MCS with advisory back-link fields maintained with CAS().
4915 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4916 // The validity of the backlinks must be ratified before we trust the value.
4917 // If the backlinks are invalid the exiting thread must back-track through the
4918 // the forward links, which are always trustworthy.
4919 // * Add a successor indication. The LockWord is currently encoded as
4920 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4921 // to provide the usual futile-wakeup optimization.
4922 // See RTStt for details.
4923 //
4924
4925
4926 const intptr_t LOCKBIT = 1;
4927
4928 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4929 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4930 if (w == 0) return;
4931 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4932 return;
4933 }
4934
4935 ParkEvent * const Self = Thread::current()->_MuxEvent;
4936 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4937 for (;;) {
4938 int its = (os::is_MP() ? 100 : 0) + 1;
4939
4940 // Optional spin phase: spin-then-park strategy
4941 while (--its >= 0) {
4942 w = *Lock;
4943 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4944 return;
4945 }
4946 }
4947
4948 Self->reset();
4949 Self->OnList = intptr_t(Lock);
4950 // The following fence() isn't _strictly necessary as the subsequent
4951 // CAS() both serializes execution and ratifies the fetched *Lock value.
4952 OrderAccess::fence();
4953 for (;;) {
4954 w = *Lock;
4955 if ((w & LOCKBIT) == 0) {
4956 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4957 Self->OnList = 0; // hygiene - allows stronger asserts
4958 return;
4959 }
4960 continue; // Interference -- *Lock changed -- Just retry
4961 }
4962 assert(w & LOCKBIT, "invariant");
4963 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4964 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4965 }
4966
4967 while (Self->OnList != 0) {
4968 Self->park();
4969 }
4970 }
4971 }
4972
4973 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4974 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4975 if (w == 0) return;
4976 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4977 return;
4978 }
4979
4980 ParkEvent * ReleaseAfter = NULL;
4981 if (ev == NULL) {
4982 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4983 }
4984 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4985 for (;;) {
4986 guarantee(ev->OnList == 0, "invariant");
4987 int its = (os::is_MP() ? 100 : 0) + 1;
4988
4989 // Optional spin phase: spin-then-park strategy
4990 while (--its >= 0) {
4991 w = *Lock;
4992 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4993 if (ReleaseAfter != NULL) {
4994 ParkEvent::Release(ReleaseAfter);
4995 }
4996 return;
4997 }
4998 }
4999
5000 ev->reset();
5001 ev->OnList = intptr_t(Lock);
5002 // The following fence() isn't _strictly necessary as the subsequent
5003 // CAS() both serializes execution and ratifies the fetched *Lock value.
5004 OrderAccess::fence();
5005 for (;;) {
5006 w = *Lock;
5007 if ((w & LOCKBIT) == 0) {
5008 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
5009 ev->OnList = 0;
5010 // We call ::Release while holding the outer lock, thus
5011 // artificially lengthening the critical section.
5012 // Consider deferring the ::Release() until the subsequent unlock(),
5013 // after we've dropped the outer lock.
5014 if (ReleaseAfter != NULL) {
5015 ParkEvent::Release(ReleaseAfter);
5016 }
5017 return;
5018 }
5019 continue; // Interference -- *Lock changed -- Just retry
5020 }
5021 assert(w & LOCKBIT, "invariant");
5022 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
5023 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
5024 }
5025
5026 while (ev->OnList != 0) {
5027 ev->park();
5028 }
5029 }
5030 }
5031
5032 // Release() must extract a successor from the list and then wake that thread.
5033 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
5034 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
5035 // Release() would :
5036 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
5037 // (B) Extract a successor from the private list "in-hand"
5038 // (C) attempt to CAS() the residual back into *Lock over null.
5039 // If there were any newly arrived threads and the CAS() would fail.
5040 // In that case Release() would detach the RATs, re-merge the list in-hand
5041 // with the RATs and repeat as needed. Alternately, Release() might
5042 // detach and extract a successor, but then pass the residual list to the wakee.
5043 // The wakee would be responsible for reattaching and remerging before it
5044 // competed for the lock.
5045 //
5046 // Both "pop" and DMR are immune from ABA corruption -- there can be
5047 // multiple concurrent pushers, but only one popper or detacher.
5048 // This implementation pops from the head of the list. This is unfair,
5049 // but tends to provide excellent throughput as hot threads remain hot.
5050 // (We wake recently run threads first).
5051 //
5052 // All paths through muxRelease() will execute a CAS.
5053 // Release consistency -- We depend on the CAS in muxRelease() to provide full
5054 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
5055 // executed within the critical section are complete and globally visible before the
5056 // store (CAS) to the lock-word that releases the lock becomes globally visible.
5057 void Thread::muxRelease(volatile intptr_t * Lock) {
5058 for (;;) {
5059 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
5060 assert(w & LOCKBIT, "invariant");
5061 if (w == LOCKBIT) return;
5062 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
5063 assert(List != NULL, "invariant");
5064 assert(List->OnList == intptr_t(Lock), "invariant");
5065 ParkEvent * const nxt = List->ListNext;
5066 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5067
5068 // The following CAS() releases the lock and pops the head element.
5069 // The CAS() also ratifies the previously fetched lock-word value.
5070 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
5071 continue;
5072 }
5073 List->OnList = 0;
5074 OrderAccess::fence();
5075 List->unpark();
5076 return;
5077 }
5078 }
5079
5080
5081 void Threads::verify() {
5082 ALL_JAVA_THREADS(p) {
5083 p->verify();
5084 }
5085 VMThread* thread = VMThread::vm_thread();
5086 if (thread != NULL) thread->verify();
5087 }