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 // Initial value of zero ==> never claimed.
242 _threads_do_token = 0;
243 _threads_hazard_ptr = NULL;
244 _threads_list_ptr = NULL;
245 _nested_threads_hazard_ptr_cnt = 0;
246 _rcu_counter = 0;
247
248 // the handle mark links itself to last_handle_mark
249 new HandleMark(this);
250
251 // plain initialization
252 debug_only(_owned_locks = NULL;)
253 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_par_threads_do(uintx claim_token) {
889 uintx token = _threads_do_token;
890 if (token != claim_token) {
891 uintx res = Atomic::cmpxchg(claim_token, &_threads_do_token, token);
892 if (res == token) {
893 return true;
894 }
895 guarantee(res == claim_token, "invariant");
896 }
897 return false;
898 }
899
900 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
901 active_handles()->oops_do(f);
902 // Do oop for ThreadShadow
903 f->do_oop((oop*)&_pending_exception);
904 handle_area()->oops_do(f);
905
906 // We scan thread local monitor lists here, and the remaining global
907 // monitors in ObjectSynchronizer::oops_do().
908 ObjectSynchronizer::thread_local_used_oops_do(this, f);
909 }
910
911 void Thread::metadata_handles_do(void f(Metadata*)) {
912 // Only walk the Handles in Thread.
913 if (metadata_handles() != NULL) {
914 for (int i = 0; i< metadata_handles()->length(); i++) {
915 f(metadata_handles()->at(i));
916 }
917 }
918 }
919
920 void Thread::print_on(outputStream* st, bool print_extended_info) const {
921 // get_priority assumes osthread initialized
922 if (osthread() != NULL) {
923 int os_prio;
924 if (os::get_native_priority(this, &os_prio) == OS_OK) {
925 st->print("os_prio=%d ", os_prio);
926 }
927
928 st->print("cpu=%.2fms ",
929 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
930 );
931 st->print("elapsed=%.2fs ",
932 _statistical_info.getElapsedTime() / 1000.0
933 );
934 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
935 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
936 st->print("allocated=" SIZE_FORMAT "%s ",
937 byte_size_in_proper_unit(allocated_bytes),
938 proper_unit_for_byte_size(allocated_bytes)
939 );
940 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
941 }
942
943 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
944 osthread()->print_on(st);
945 }
946 ThreadsSMRSupport::print_info_on(this, st);
947 st->print(" ");
948 debug_only(if (WizardMode) print_owned_locks_on(st);)
949 }
950
951 // Thread::print_on_error() is called by fatal error handler. Don't use
952 // any lock or allocate memory.
953 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
954 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
955
956 if (is_VM_thread()) { st->print("VMThread"); }
957 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
958 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
959 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
960 else { st->print("Thread"); }
961
962 if (is_Named_thread()) {
963 st->print(" \"%s\"", name());
964 }
965
966 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
967 p2i(stack_end()), p2i(stack_base()));
968
969 if (osthread()) {
970 st->print(" [id=%d]", osthread()->thread_id());
971 }
972
973 ThreadsSMRSupport::print_info_on(this, st);
974 }
975
976 void Thread::print_value_on(outputStream* st) const {
977 if (is_Named_thread()) {
978 st->print(" \"%s\" ", name());
979 }
980 st->print(INTPTR_FORMAT, p2i(this)); // print address
981 }
982
983 #ifdef ASSERT
984 void Thread::print_owned_locks_on(outputStream* st) const {
985 Monitor *cur = _owned_locks;
986 if (cur == NULL) {
987 st->print(" (no locks) ");
988 } else {
989 st->print_cr(" Locks owned:");
990 while (cur) {
991 cur->print_on(st);
992 cur = cur->next();
993 }
994 }
995 }
996
997 static int ref_use_count = 0;
998
999 bool Thread::owns_locks_but_compiled_lock() const {
1000 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1001 if (cur != Compile_lock) return true;
1002 }
1003 return false;
1004 }
1005
1006
1007 #endif
1008
1009 #ifndef PRODUCT
1010
1011 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
1012 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
1013 // no locks which allow_vm_block's are held
1014 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
1015 // Check if current thread is allowed to block at a safepoint
1016 if (!(_allow_safepoint_count == 0)) {
1017 fatal("Possible safepoint reached by thread that does not allow it");
1018 }
1019 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
1020 fatal("LEAF method calling lock?");
1021 }
1022
1023 #ifdef ASSERT
1024 if (potential_vm_operation && is_Java_thread()
1025 && !Universe::is_bootstrapping()) {
1026 // Make sure we do not hold any locks that the VM thread also uses.
1027 // This could potentially lead to deadlocks
1028 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1029 // Threads_lock is special, since the safepoint synchronization will not start before this is
1030 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
1031 // since it is used to transfer control between JavaThreads and the VMThread
1032 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
1033 if ((cur->allow_vm_block() &&
1034 cur != Threads_lock &&
1035 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
1036 cur != VMOperationRequest_lock &&
1037 cur != VMOperationQueue_lock) ||
1038 cur->rank() == Mutex::special) {
1039 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
1040 }
1041 }
1042 }
1043
1044 if (GCALotAtAllSafepoints) {
1045 // We could enter a safepoint here and thus have a gc
1046 InterfaceSupport::check_gc_alot();
1047 }
1048 #endif
1049 }
1050 #endif
1051
1052 bool Thread::is_in_stack(address adr) const {
1053 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1054 address end = os::current_stack_pointer();
1055 // Allow non Java threads to call this without stack_base
1056 if (_stack_base == NULL) return true;
1057 if (stack_base() >= adr && adr >= end) return true;
1058
1059 return false;
1060 }
1061
1062 bool Thread::is_in_usable_stack(address adr) const {
1063 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1064 size_t usable_stack_size = _stack_size - stack_guard_size;
1065
1066 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1067 }
1068
1069
1070 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1071 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1072 // used for compilation in the future. If that change is made, the need for these methods
1073 // should be revisited, and they should be removed if possible.
1074
1075 bool Thread::is_lock_owned(address adr) const {
1076 return on_local_stack(adr);
1077 }
1078
1079 bool Thread::set_as_starting_thread() {
1080 assert(_starting_thread == NULL, "already initialized: "
1081 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
1082 // NOTE: this must be called inside the main thread.
1083 DEBUG_ONLY(_starting_thread = this;)
1084 return os::create_main_thread((JavaThread*)this);
1085 }
1086
1087 static void initialize_class(Symbol* class_name, TRAPS) {
1088 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1089 InstanceKlass::cast(klass)->initialize(CHECK);
1090 }
1091
1092
1093 // Creates the initial ThreadGroup
1094 static Handle create_initial_thread_group(TRAPS) {
1095 Handle system_instance = JavaCalls::construct_new_instance(
1096 SystemDictionary::ThreadGroup_klass(),
1097 vmSymbols::void_method_signature(),
1098 CHECK_NH);
1099 Universe::set_system_thread_group(system_instance());
1100
1101 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1102 Handle main_instance = JavaCalls::construct_new_instance(
1103 SystemDictionary::ThreadGroup_klass(),
1104 vmSymbols::threadgroup_string_void_signature(),
1105 system_instance,
1106 string,
1107 CHECK_NH);
1108 return main_instance;
1109 }
1110
1111 // Creates the initial Thread
1112 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1113 TRAPS) {
1114 InstanceKlass* ik = SystemDictionary::Thread_klass();
1115 assert(ik->is_initialized(), "must be");
1116 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1117
1118 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1119 // constructor calls Thread.current(), which must be set here for the
1120 // initial thread.
1121 java_lang_Thread::set_thread(thread_oop(), thread);
1122 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1123 thread->set_threadObj(thread_oop());
1124
1125 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1126
1127 JavaValue result(T_VOID);
1128 JavaCalls::call_special(&result, thread_oop,
1129 ik,
1130 vmSymbols::object_initializer_name(),
1131 vmSymbols::threadgroup_string_void_signature(),
1132 thread_group,
1133 string,
1134 CHECK_NULL);
1135 return thread_oop();
1136 }
1137
1138 char java_runtime_name[128] = "";
1139 char java_runtime_version[128] = "";
1140
1141 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1142 static const char* get_java_runtime_name(TRAPS) {
1143 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1144 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1145 fieldDescriptor fd;
1146 bool found = k != NULL &&
1147 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1148 vmSymbols::string_signature(), &fd);
1149 if (found) {
1150 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1151 if (name_oop == NULL) {
1152 return NULL;
1153 }
1154 const char* name = java_lang_String::as_utf8_string(name_oop,
1155 java_runtime_name,
1156 sizeof(java_runtime_name));
1157 return name;
1158 } else {
1159 return NULL;
1160 }
1161 }
1162
1163 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1164 static const char* get_java_runtime_version(TRAPS) {
1165 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1166 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1167 fieldDescriptor fd;
1168 bool found = k != NULL &&
1169 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1170 vmSymbols::string_signature(), &fd);
1171 if (found) {
1172 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1173 if (name_oop == NULL) {
1174 return NULL;
1175 }
1176 const char* name = java_lang_String::as_utf8_string(name_oop,
1177 java_runtime_version,
1178 sizeof(java_runtime_version));
1179 return name;
1180 } else {
1181 return NULL;
1182 }
1183 }
1184
1185 // General purpose hook into Java code, run once when the VM is initialized.
1186 // The Java library method itself may be changed independently from the VM.
1187 static void call_postVMInitHook(TRAPS) {
1188 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1189 if (klass != NULL) {
1190 JavaValue result(T_VOID);
1191 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1192 vmSymbols::void_method_signature(),
1193 CHECK);
1194 }
1195 }
1196
1197 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1198 bool daemon, TRAPS) {
1199 assert(thread_group.not_null(), "thread group should be specified");
1200 assert(threadObj() == NULL, "should only create Java thread object once");
1201
1202 InstanceKlass* ik = SystemDictionary::Thread_klass();
1203 assert(ik->is_initialized(), "must be");
1204 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1205
1206 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1207 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1208 // constructor calls Thread.current(), which must be set here.
1209 java_lang_Thread::set_thread(thread_oop(), this);
1210 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1211 set_threadObj(thread_oop());
1212
1213 JavaValue result(T_VOID);
1214 if (thread_name != NULL) {
1215 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1216 // Thread gets assigned specified name and null target
1217 JavaCalls::call_special(&result,
1218 thread_oop,
1219 ik,
1220 vmSymbols::object_initializer_name(),
1221 vmSymbols::threadgroup_string_void_signature(),
1222 thread_group,
1223 name,
1224 THREAD);
1225 } else {
1226 // Thread gets assigned name "Thread-nnn" and null target
1227 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1228 JavaCalls::call_special(&result,
1229 thread_oop,
1230 ik,
1231 vmSymbols::object_initializer_name(),
1232 vmSymbols::threadgroup_runnable_void_signature(),
1233 thread_group,
1234 Handle(),
1235 THREAD);
1236 }
1237
1238
1239 if (daemon) {
1240 java_lang_Thread::set_daemon(thread_oop());
1241 }
1242
1243 if (HAS_PENDING_EXCEPTION) {
1244 return;
1245 }
1246
1247 Klass* group = SystemDictionary::ThreadGroup_klass();
1248 Handle threadObj(THREAD, this->threadObj());
1249
1250 JavaCalls::call_special(&result,
1251 thread_group,
1252 group,
1253 vmSymbols::add_method_name(),
1254 vmSymbols::thread_void_signature(),
1255 threadObj, // Arg 1
1256 THREAD);
1257 }
1258
1259 // List of all NonJavaThreads and safe iteration over that list.
1260
1261 class NonJavaThread::List {
1262 public:
1263 NonJavaThread* volatile _head;
1264 SingleWriterSynchronizer _protect;
1265
1266 List() : _head(NULL), _protect() {}
1267 };
1268
1269 NonJavaThread::List NonJavaThread::_the_list;
1270
1271 NonJavaThread::Iterator::Iterator() :
1272 _protect_enter(_the_list._protect.enter()),
1273 _current(OrderAccess::load_acquire(&_the_list._head))
1274 {}
1275
1276 NonJavaThread::Iterator::~Iterator() {
1277 _the_list._protect.exit(_protect_enter);
1278 }
1279
1280 void NonJavaThread::Iterator::step() {
1281 assert(!end(), "precondition");
1282 _current = OrderAccess::load_acquire(&_current->_next);
1283 }
1284
1285 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) {
1286 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!");
1287 }
1288
1289 NonJavaThread::~NonJavaThread() { }
1290
1291 void NonJavaThread::add_to_the_list() {
1292 MutexLockerEx ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1293 // Initialize BarrierSet-related data before adding to list.
1294 BarrierSet::barrier_set()->on_thread_attach(this);
1295 OrderAccess::release_store(&_next, _the_list._head);
1296 OrderAccess::release_store(&_the_list._head, this);
1297 }
1298
1299 void NonJavaThread::remove_from_the_list() {
1300 {
1301 MutexLockerEx ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag);
1302 // Cleanup BarrierSet-related data before removing from list.
1303 BarrierSet::barrier_set()->on_thread_detach(this);
1304 NonJavaThread* volatile* p = &_the_list._head;
1305 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) {
1306 if (t == this) {
1307 *p = _next;
1308 break;
1309 }
1310 }
1311 }
1312 // Wait for any in-progress iterators. Concurrent synchronize is not
1313 // allowed, so do it while holding a dedicated lock. Outside and distinct
1314 // from NJTList_lock in case an iteration attempts to lock it.
1315 MutexLockerEx ml(NonJavaThreadsListSync_lock, Mutex::_no_safepoint_check_flag);
1316 _the_list._protect.synchronize();
1317 _next = NULL; // Safe to drop the link now.
1318 }
1319
1320 void NonJavaThread::pre_run() {
1321 add_to_the_list();
1322
1323 // This is slightly odd in that NamedThread is a subclass, but
1324 // in fact name() is defined in Thread
1325 assert(this->name() != NULL, "thread name was not set before it was started");
1326 this->set_native_thread_name(this->name());
1327 }
1328
1329 void NonJavaThread::post_run() {
1330 JFR_ONLY(Jfr::on_thread_exit(this);)
1331 remove_from_the_list();
1332 // Ensure thread-local-storage is cleared before termination.
1333 Thread::clear_thread_current();
1334 }
1335
1336 // NamedThread -- non-JavaThread subclasses with multiple
1337 // uniquely named instances should derive from this.
1338 NamedThread::NamedThread() :
1339 NonJavaThread(),
1340 _name(NULL),
1341 _processed_thread(NULL),
1342 _gc_id(GCId::undefined())
1343 {}
1344
1345 NamedThread::~NamedThread() {
1346 if (_name != NULL) {
1347 FREE_C_HEAP_ARRAY(char, _name);
1348 _name = NULL;
1349 }
1350 }
1351
1352 void NamedThread::set_name(const char* format, ...) {
1353 guarantee(_name == NULL, "Only get to set name once.");
1354 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1355 guarantee(_name != NULL, "alloc failure");
1356 va_list ap;
1357 va_start(ap, format);
1358 jio_vsnprintf(_name, max_name_len, format, ap);
1359 va_end(ap);
1360 }
1361
1362 void NamedThread::print_on(outputStream* st) const {
1363 st->print("\"%s\" ", name());
1364 Thread::print_on(st);
1365 st->cr();
1366 }
1367
1368
1369 // ======= WatcherThread ========
1370
1371 // The watcher thread exists to simulate timer interrupts. It should
1372 // be replaced by an abstraction over whatever native support for
1373 // timer interrupts exists on the platform.
1374
1375 WatcherThread* WatcherThread::_watcher_thread = NULL;
1376 bool WatcherThread::_startable = false;
1377 volatile bool WatcherThread::_should_terminate = false;
1378
1379 WatcherThread::WatcherThread() : NonJavaThread() {
1380 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1381 if (os::create_thread(this, os::watcher_thread)) {
1382 _watcher_thread = this;
1383
1384 // Set the watcher thread to the highest OS priority which should not be
1385 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1386 // is created. The only normal thread using this priority is the reference
1387 // handler thread, which runs for very short intervals only.
1388 // If the VMThread's priority is not lower than the WatcherThread profiling
1389 // will be inaccurate.
1390 os::set_priority(this, MaxPriority);
1391 if (!DisableStartThread) {
1392 os::start_thread(this);
1393 }
1394 }
1395 }
1396
1397 int WatcherThread::sleep() const {
1398 // The WatcherThread does not participate in the safepoint protocol
1399 // for the PeriodicTask_lock because it is not a JavaThread.
1400 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1401
1402 if (_should_terminate) {
1403 // check for termination before we do any housekeeping or wait
1404 return 0; // we did not sleep.
1405 }
1406
1407 // remaining will be zero if there are no tasks,
1408 // causing the WatcherThread to sleep until a task is
1409 // enrolled
1410 int remaining = PeriodicTask::time_to_wait();
1411 int time_slept = 0;
1412
1413 // we expect this to timeout - we only ever get unparked when
1414 // we should terminate or when a new task has been enrolled
1415 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1416
1417 jlong time_before_loop = os::javaTimeNanos();
1418
1419 while (true) {
1420 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1421 remaining);
1422 jlong now = os::javaTimeNanos();
1423
1424 if (remaining == 0) {
1425 // if we didn't have any tasks we could have waited for a long time
1426 // consider the time_slept zero and reset time_before_loop
1427 time_slept = 0;
1428 time_before_loop = now;
1429 } else {
1430 // need to recalculate since we might have new tasks in _tasks
1431 time_slept = (int) ((now - time_before_loop) / 1000000);
1432 }
1433
1434 // Change to task list or spurious wakeup of some kind
1435 if (timedout || _should_terminate) {
1436 break;
1437 }
1438
1439 remaining = PeriodicTask::time_to_wait();
1440 if (remaining == 0) {
1441 // Last task was just disenrolled so loop around and wait until
1442 // another task gets enrolled
1443 continue;
1444 }
1445
1446 remaining -= time_slept;
1447 if (remaining <= 0) {
1448 break;
1449 }
1450 }
1451
1452 return time_slept;
1453 }
1454
1455 void WatcherThread::run() {
1456 assert(this == watcher_thread(), "just checking");
1457
1458 this->set_active_handles(JNIHandleBlock::allocate_block());
1459 while (true) {
1460 assert(watcher_thread() == Thread::current(), "thread consistency check");
1461 assert(watcher_thread() == this, "thread consistency check");
1462
1463 // Calculate how long it'll be until the next PeriodicTask work
1464 // should be done, and sleep that amount of time.
1465 int time_waited = sleep();
1466
1467 if (VMError::is_error_reported()) {
1468 // A fatal error has happened, the error handler(VMError::report_and_die)
1469 // should abort JVM after creating an error log file. However in some
1470 // rare cases, the error handler itself might deadlock. Here periodically
1471 // check for error reporting timeouts, and if it happens, just proceed to
1472 // abort the VM.
1473
1474 // This code is in WatcherThread because WatcherThread wakes up
1475 // periodically so the fatal error handler doesn't need to do anything;
1476 // also because the WatcherThread is less likely to crash than other
1477 // threads.
1478
1479 for (;;) {
1480 // Note: we use naked sleep in this loop because we want to avoid using
1481 // any kind of VM infrastructure which may be broken at this point.
1482 if (VMError::check_timeout()) {
1483 // We hit error reporting timeout. Error reporting was interrupted and
1484 // will be wrapping things up now (closing files etc). Give it some more
1485 // time, then quit the VM.
1486 os::naked_short_sleep(200);
1487 // Print a message to stderr.
1488 fdStream err(defaultStream::output_fd());
1489 err.print_raw_cr("# [ timer expired, abort... ]");
1490 // skip atexit/vm_exit/vm_abort hooks
1491 os::die();
1492 }
1493
1494 // Wait a second, then recheck for timeout.
1495 os::naked_short_sleep(999);
1496 }
1497 }
1498
1499 if (_should_terminate) {
1500 // check for termination before posting the next tick
1501 break;
1502 }
1503
1504 PeriodicTask::real_time_tick(time_waited);
1505 }
1506
1507 // Signal that it is terminated
1508 {
1509 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1510 _watcher_thread = NULL;
1511 Terminator_lock->notify_all();
1512 }
1513 }
1514
1515 void WatcherThread::start() {
1516 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1517
1518 if (watcher_thread() == NULL && _startable) {
1519 _should_terminate = false;
1520 // Create the single instance of WatcherThread
1521 new WatcherThread();
1522 }
1523 }
1524
1525 void WatcherThread::make_startable() {
1526 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1527 _startable = true;
1528 }
1529
1530 void WatcherThread::stop() {
1531 {
1532 // Follow normal safepoint aware lock enter protocol since the
1533 // WatcherThread is stopped by another JavaThread.
1534 MutexLocker ml(PeriodicTask_lock);
1535 _should_terminate = true;
1536
1537 WatcherThread* watcher = watcher_thread();
1538 if (watcher != NULL) {
1539 // unpark the WatcherThread so it can see that it should terminate
1540 watcher->unpark();
1541 }
1542 }
1543
1544 MutexLocker mu(Terminator_lock);
1545
1546 while (watcher_thread() != NULL) {
1547 // This wait should make safepoint checks, wait without a timeout,
1548 // and wait as a suspend-equivalent condition.
1549 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1550 Mutex::_as_suspend_equivalent_flag);
1551 }
1552 }
1553
1554 void WatcherThread::unpark() {
1555 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1556 PeriodicTask_lock->notify();
1557 }
1558
1559 void WatcherThread::print_on(outputStream* st) const {
1560 st->print("\"%s\" ", name());
1561 Thread::print_on(st);
1562 st->cr();
1563 }
1564
1565 // ======= JavaThread ========
1566
1567 #if INCLUDE_JVMCI
1568
1569 jlong* JavaThread::_jvmci_old_thread_counters;
1570
1571 bool jvmci_counters_include(JavaThread* thread) {
1572 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1573 }
1574
1575 void JavaThread::collect_counters(typeArrayOop array) {
1576 if (JVMCICounterSize > 0) {
1577 JavaThreadIteratorWithHandle jtiwh;
1578 for (int i = 0; i < array->length(); i++) {
1579 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1580 }
1581 for (; JavaThread *tp = jtiwh.next(); ) {
1582 if (jvmci_counters_include(tp)) {
1583 for (int i = 0; i < array->length(); i++) {
1584 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1585 }
1586 }
1587 }
1588 }
1589 }
1590
1591 #endif // INCLUDE_JVMCI
1592
1593 // A JavaThread is a normal Java thread
1594
1595 void JavaThread::initialize() {
1596 // Initialize fields
1597
1598 set_saved_exception_pc(NULL);
1599 set_threadObj(NULL);
1600 _anchor.clear();
1601 set_entry_point(NULL);
1602 set_jni_functions(jni_functions());
1603 set_callee_target(NULL);
1604 set_vm_result(NULL);
1605 set_vm_result_2(NULL);
1606 set_vframe_array_head(NULL);
1607 set_vframe_array_last(NULL);
1608 set_deferred_locals(NULL);
1609 set_deopt_mark(NULL);
1610 set_deopt_compiled_method(NULL);
1611 clear_must_deopt_id();
1612 set_monitor_chunks(NULL);
1613 set_next(NULL);
1614 _on_thread_list = false;
1615 set_thread_state(_thread_new);
1616 _terminated = _not_terminated;
1617 _array_for_gc = NULL;
1618 _suspend_equivalent = false;
1619 _in_deopt_handler = 0;
1620 _doing_unsafe_access = false;
1621 _stack_guard_state = stack_guard_unused;
1622 #if INCLUDE_JVMCI
1623 _pending_monitorenter = false;
1624 _pending_deoptimization = -1;
1625 _pending_failed_speculation = 0;
1626 _pending_transfer_to_interpreter = false;
1627 _adjusting_comp_level = false;
1628 _in_retryable_allocation = false;
1629 _jvmci._alternate_call_target = NULL;
1630 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1631 if (JVMCICounterSize > 0) {
1632 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1633 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1634 } else {
1635 _jvmci_counters = NULL;
1636 }
1637 #endif // INCLUDE_JVMCI
1638 _reserved_stack_activation = NULL; // stack base not known yet
1639 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1640 _exception_pc = 0;
1641 _exception_handler_pc = 0;
1642 _is_method_handle_return = 0;
1643 _jvmti_thread_state= NULL;
1644 _should_post_on_exceptions_flag = JNI_FALSE;
1645 _interp_only_mode = 0;
1646 _special_runtime_exit_condition = _no_async_condition;
1647 _pending_async_exception = NULL;
1648 _thread_stat = NULL;
1649 _thread_stat = new ThreadStatistics();
1650 _blocked_on_compilation = false;
1651 _jni_active_critical = 0;
1652 _pending_jni_exception_check_fn = NULL;
1653 _do_not_unlock_if_synchronized = false;
1654 _cached_monitor_info = NULL;
1655 _parker = Parker::Allocate(this);
1656
1657 #ifndef PRODUCT
1658 _jmp_ring_index = 0;
1659 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1660 record_jump(NULL, NULL, NULL, 0);
1661 }
1662 #endif // PRODUCT
1663
1664 // Setup safepoint state info for this thread
1665 ThreadSafepointState::create(this);
1666
1667 debug_only(_java_call_counter = 0);
1668
1669 // JVMTI PopFrame support
1670 _popframe_condition = popframe_inactive;
1671 _popframe_preserved_args = NULL;
1672 _popframe_preserved_args_size = 0;
1673 _frames_to_pop_failed_realloc = 0;
1674
1675 if (SafepointMechanism::uses_thread_local_poll()) {
1676 SafepointMechanism::initialize_header(this);
1677 }
1678
1679 _class_to_be_initialized = NULL;
1680
1681 pd_initialize();
1682 }
1683
1684 JavaThread::JavaThread(bool is_attaching_via_jni) :
1685 Thread() {
1686 initialize();
1687 if (is_attaching_via_jni) {
1688 _jni_attach_state = _attaching_via_jni;
1689 } else {
1690 _jni_attach_state = _not_attaching_via_jni;
1691 }
1692 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1693 }
1694
1695 bool JavaThread::reguard_stack(address cur_sp) {
1696 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1697 && _stack_guard_state != stack_guard_reserved_disabled) {
1698 return true; // Stack already guarded or guard pages not needed.
1699 }
1700
1701 if (register_stack_overflow()) {
1702 // For those architectures which have separate register and
1703 // memory stacks, we must check the register stack to see if
1704 // it has overflowed.
1705 return false;
1706 }
1707
1708 // Java code never executes within the yellow zone: the latter is only
1709 // there to provoke an exception during stack banging. If java code
1710 // is executing there, either StackShadowPages should be larger, or
1711 // some exception code in c1, c2 or the interpreter isn't unwinding
1712 // when it should.
1713 guarantee(cur_sp > stack_reserved_zone_base(),
1714 "not enough space to reguard - increase StackShadowPages");
1715 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1716 enable_stack_yellow_reserved_zone();
1717 if (reserved_stack_activation() != stack_base()) {
1718 set_reserved_stack_activation(stack_base());
1719 }
1720 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1721 set_reserved_stack_activation(stack_base());
1722 enable_stack_reserved_zone();
1723 }
1724 return true;
1725 }
1726
1727 bool JavaThread::reguard_stack(void) {
1728 return reguard_stack(os::current_stack_pointer());
1729 }
1730
1731
1732 void JavaThread::block_if_vm_exited() {
1733 if (_terminated == _vm_exited) {
1734 // _vm_exited is set at safepoint, and Threads_lock is never released
1735 // we will block here forever
1736 Threads_lock->lock_without_safepoint_check();
1737 ShouldNotReachHere();
1738 }
1739 }
1740
1741
1742 // Remove this ifdef when C1 is ported to the compiler interface.
1743 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1744 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1745
1746 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1747 Thread() {
1748 initialize();
1749 _jni_attach_state = _not_attaching_via_jni;
1750 set_entry_point(entry_point);
1751 // Create the native thread itself.
1752 // %note runtime_23
1753 os::ThreadType thr_type = os::java_thread;
1754 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1755 os::java_thread;
1756 os::create_thread(this, thr_type, stack_sz);
1757 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1758 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1759 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1760 // the exception consists of creating the exception object & initializing it, initialization
1761 // will leave the VM via a JavaCall and then all locks must be unlocked).
1762 //
1763 // The thread is still suspended when we reach here. Thread must be explicit started
1764 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1765 // by calling Threads:add. The reason why this is not done here, is because the thread
1766 // object must be fully initialized (take a look at JVM_Start)
1767 }
1768
1769 JavaThread::~JavaThread() {
1770
1771 // JSR166 -- return the parker to the free list
1772 Parker::Release(_parker);
1773 _parker = NULL;
1774
1775 // Free any remaining previous UnrollBlock
1776 vframeArray* old_array = vframe_array_last();
1777
1778 if (old_array != NULL) {
1779 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1780 old_array->set_unroll_block(NULL);
1781 delete old_info;
1782 delete old_array;
1783 }
1784
1785 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1786 if (deferred != NULL) {
1787 // This can only happen if thread is destroyed before deoptimization occurs.
1788 assert(deferred->length() != 0, "empty array!");
1789 do {
1790 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1791 deferred->remove_at(0);
1792 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1793 delete dlv;
1794 } while (deferred->length() != 0);
1795 delete deferred;
1796 }
1797
1798 // All Java related clean up happens in exit
1799 ThreadSafepointState::destroy(this);
1800 if (_thread_stat != NULL) delete _thread_stat;
1801
1802 #if INCLUDE_JVMCI
1803 if (JVMCICounterSize > 0) {
1804 if (jvmci_counters_include(this)) {
1805 for (int i = 0; i < JVMCICounterSize; i++) {
1806 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1807 }
1808 }
1809 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1810 }
1811 #endif // INCLUDE_JVMCI
1812 }
1813
1814
1815 // First JavaThread specific code executed by a new Java thread.
1816 void JavaThread::pre_run() {
1817 // empty - see comments in run()
1818 }
1819
1820 // The main routine called by a new Java thread. This isn't overridden
1821 // by subclasses, instead different subclasses define a different "entry_point"
1822 // which defines the actual logic for that kind of thread.
1823 void JavaThread::run() {
1824 // initialize thread-local alloc buffer related fields
1825 this->initialize_tlab();
1826
1827 // Used to test validity of stack trace backs.
1828 // This can't be moved into pre_run() else we invalidate
1829 // the requirement that thread_main_inner is lower on
1830 // the stack. Consequently all the initialization logic
1831 // stays here in run() rather than pre_run().
1832 this->record_base_of_stack_pointer();
1833
1834 this->create_stack_guard_pages();
1835
1836 this->cache_global_variables();
1837
1838 // Thread is now sufficiently initialized to be handled by the safepoint code as being
1839 // in the VM. Change thread state from _thread_new to _thread_in_vm
1840 ThreadStateTransition::transition(this, _thread_new, _thread_in_vm);
1841 // Before a thread is on the threads list it is always safe, so after leaving the
1842 // _thread_new we should emit a instruction barrier. The distance to modified code
1843 // from here is probably far enough, but this is consistent and safe.
1844 OrderAccess::cross_modify_fence();
1845
1846 assert(JavaThread::current() == this, "sanity check");
1847 assert(!Thread::current()->owns_locks(), "sanity check");
1848
1849 DTRACE_THREAD_PROBE(start, this);
1850
1851 // This operation might block. We call that after all safepoint checks for a new thread has
1852 // been completed.
1853 this->set_active_handles(JNIHandleBlock::allocate_block());
1854
1855 if (JvmtiExport::should_post_thread_life()) {
1856 JvmtiExport::post_thread_start(this);
1857
1858 }
1859
1860 // We call another function to do the rest so we are sure that the stack addresses used
1861 // from there will be lower than the stack base just computed.
1862 thread_main_inner();
1863 }
1864
1865 void JavaThread::thread_main_inner() {
1866 assert(JavaThread::current() == this, "sanity check");
1867 assert(this->threadObj() != NULL, "just checking");
1868
1869 // Execute thread entry point unless this thread has a pending exception
1870 // or has been stopped before starting.
1871 // Note: Due to JVM_StopThread we can have pending exceptions already!
1872 if (!this->has_pending_exception() &&
1873 !java_lang_Thread::is_stillborn(this->threadObj())) {
1874 {
1875 ResourceMark rm(this);
1876 this->set_native_thread_name(this->get_thread_name());
1877 }
1878 HandleMark hm(this);
1879 this->entry_point()(this, this);
1880 }
1881
1882 DTRACE_THREAD_PROBE(stop, this);
1883
1884 // Cleanup is handled in post_run()
1885 }
1886
1887 // Shared teardown for all JavaThreads
1888 void JavaThread::post_run() {
1889 this->exit(false);
1890 // Defer deletion to here to ensure 'this' is still referenceable in call_run
1891 // for any shared tear-down.
1892 this->smr_delete();
1893 }
1894
1895 static void ensure_join(JavaThread* thread) {
1896 // We do not need to grab the Threads_lock, since we are operating on ourself.
1897 Handle threadObj(thread, thread->threadObj());
1898 assert(threadObj.not_null(), "java thread object must exist");
1899 ObjectLocker lock(threadObj, thread);
1900 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1901 thread->clear_pending_exception();
1902 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1903 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1904 // Clear the native thread instance - this makes isAlive return false and allows the join()
1905 // to complete once we've done the notify_all below
1906 java_lang_Thread::set_thread(threadObj(), NULL);
1907 lock.notify_all(thread);
1908 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1909 thread->clear_pending_exception();
1910 }
1911
1912 static bool is_daemon(oop threadObj) {
1913 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
1914 }
1915
1916 // For any new cleanup additions, please check to see if they need to be applied to
1917 // cleanup_failed_attach_current_thread as well.
1918 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1919 assert(this == JavaThread::current(), "thread consistency check");
1920
1921 elapsedTimer _timer_exit_phase1;
1922 elapsedTimer _timer_exit_phase2;
1923 elapsedTimer _timer_exit_phase3;
1924 elapsedTimer _timer_exit_phase4;
1925
1926 if (log_is_enabled(Debug, os, thread, timer)) {
1927 _timer_exit_phase1.start();
1928 }
1929
1930 HandleMark hm(this);
1931 Handle uncaught_exception(this, this->pending_exception());
1932 this->clear_pending_exception();
1933 Handle threadObj(this, this->threadObj());
1934 assert(threadObj.not_null(), "Java thread object should be created");
1935
1936 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1937 {
1938 EXCEPTION_MARK;
1939
1940 CLEAR_PENDING_EXCEPTION;
1941 }
1942 if (!destroy_vm) {
1943 if (uncaught_exception.not_null()) {
1944 EXCEPTION_MARK;
1945 // Call method Thread.dispatchUncaughtException().
1946 Klass* thread_klass = SystemDictionary::Thread_klass();
1947 JavaValue result(T_VOID);
1948 JavaCalls::call_virtual(&result,
1949 threadObj, thread_klass,
1950 vmSymbols::dispatchUncaughtException_name(),
1951 vmSymbols::throwable_void_signature(),
1952 uncaught_exception,
1953 THREAD);
1954 if (HAS_PENDING_EXCEPTION) {
1955 ResourceMark rm(this);
1956 jio_fprintf(defaultStream::error_stream(),
1957 "\nException: %s thrown from the UncaughtExceptionHandler"
1958 " in thread \"%s\"\n",
1959 pending_exception()->klass()->external_name(),
1960 get_thread_name());
1961 CLEAR_PENDING_EXCEPTION;
1962 }
1963 }
1964 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
1965
1966 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1967 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1968 // is deprecated anyhow.
1969 if (!is_Compiler_thread()) {
1970 int count = 3;
1971 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1972 EXCEPTION_MARK;
1973 JavaValue result(T_VOID);
1974 Klass* thread_klass = SystemDictionary::Thread_klass();
1975 JavaCalls::call_virtual(&result,
1976 threadObj, thread_klass,
1977 vmSymbols::exit_method_name(),
1978 vmSymbols::void_method_signature(),
1979 THREAD);
1980 CLEAR_PENDING_EXCEPTION;
1981 }
1982 }
1983 // notify JVMTI
1984 if (JvmtiExport::should_post_thread_life()) {
1985 JvmtiExport::post_thread_end(this);
1986 }
1987
1988 // We have notified the agents that we are exiting, before we go on,
1989 // we must check for a pending external suspend request and honor it
1990 // in order to not surprise the thread that made the suspend request.
1991 while (true) {
1992 {
1993 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1994 if (!is_external_suspend()) {
1995 set_terminated(_thread_exiting);
1996 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
1997 break;
1998 }
1999 // Implied else:
2000 // Things get a little tricky here. We have a pending external
2001 // suspend request, but we are holding the SR_lock so we
2002 // can't just self-suspend. So we temporarily drop the lock
2003 // and then self-suspend.
2004 }
2005
2006 ThreadBlockInVM tbivm(this);
2007 java_suspend_self();
2008
2009 // We're done with this suspend request, but we have to loop around
2010 // and check again. Eventually we will get SR_lock without a pending
2011 // external suspend request and will be able to mark ourselves as
2012 // exiting.
2013 }
2014 // no more external suspends are allowed at this point
2015 } else {
2016 assert(!is_terminated() && !is_exiting(), "must not be exiting");
2017 // before_exit() has already posted JVMTI THREAD_END events
2018 }
2019
2020 if (log_is_enabled(Debug, os, thread, timer)) {
2021 _timer_exit_phase1.stop();
2022 _timer_exit_phase2.start();
2023 }
2024
2025 // Capture daemon status before the thread is marked as terminated.
2026 bool daemon = is_daemon(threadObj());
2027
2028 // Notify waiters on thread object. This has to be done after exit() is called
2029 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
2030 // group should have the destroyed bit set before waiters are notified).
2031 ensure_join(this);
2032 assert(!this->has_pending_exception(), "ensure_join should have cleared");
2033
2034 if (log_is_enabled(Debug, os, thread, timer)) {
2035 _timer_exit_phase2.stop();
2036 _timer_exit_phase3.start();
2037 }
2038 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
2039 // held by this thread must be released. The spec does not distinguish
2040 // between JNI-acquired and regular Java monitors. We can only see
2041 // regular Java monitors here if monitor enter-exit matching is broken.
2042 //
2043 // ensure_join() ignores IllegalThreadStateExceptions, and so does
2044 // ObjectSynchronizer::release_monitors_owned_by_thread().
2045 if (exit_type == jni_detach) {
2046 // Sanity check even though JNI DetachCurrentThread() would have
2047 // returned JNI_ERR if there was a Java frame. JavaThread exit
2048 // should be done executing Java code by the time we get here.
2049 assert(!this->has_last_Java_frame(),
2050 "should not have a Java frame when detaching or exiting");
2051 ObjectSynchronizer::release_monitors_owned_by_thread(this);
2052 assert(!this->has_pending_exception(), "release_monitors should have cleared");
2053 }
2054
2055 // These things needs to be done while we are still a Java Thread. Make sure that thread
2056 // is in a consistent state, in case GC happens
2057 JFR_ONLY(Jfr::on_thread_exit(this);)
2058
2059 if (active_handles() != NULL) {
2060 JNIHandleBlock* block = active_handles();
2061 set_active_handles(NULL);
2062 JNIHandleBlock::release_block(block);
2063 }
2064
2065 if (free_handle_block() != NULL) {
2066 JNIHandleBlock* block = free_handle_block();
2067 set_free_handle_block(NULL);
2068 JNIHandleBlock::release_block(block);
2069 }
2070
2071 // These have to be removed while this is still a valid thread.
2072 remove_stack_guard_pages();
2073
2074 if (UseTLAB) {
2075 tlab().retire();
2076 }
2077
2078 if (JvmtiEnv::environments_might_exist()) {
2079 JvmtiExport::cleanup_thread(this);
2080 }
2081
2082 // We must flush any deferred card marks and other various GC barrier
2083 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2084 // before removing a thread from the list of active threads.
2085 BarrierSet::barrier_set()->on_thread_detach(this);
2086
2087 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2088 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2089 os::current_thread_id());
2090
2091 if (log_is_enabled(Debug, os, thread, timer)) {
2092 _timer_exit_phase3.stop();
2093 _timer_exit_phase4.start();
2094 }
2095 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2096 Threads::remove(this, daemon);
2097
2098 if (log_is_enabled(Debug, os, thread, timer)) {
2099 _timer_exit_phase4.stop();
2100 ResourceMark rm(this);
2101 log_debug(os, thread, timer)("name='%s'"
2102 ", exit-phase1=" JLONG_FORMAT
2103 ", exit-phase2=" JLONG_FORMAT
2104 ", exit-phase3=" JLONG_FORMAT
2105 ", exit-phase4=" JLONG_FORMAT,
2106 get_thread_name(),
2107 _timer_exit_phase1.milliseconds(),
2108 _timer_exit_phase2.milliseconds(),
2109 _timer_exit_phase3.milliseconds(),
2110 _timer_exit_phase4.milliseconds());
2111 }
2112 }
2113
2114 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
2115 if (active_handles() != NULL) {
2116 JNIHandleBlock* block = active_handles();
2117 set_active_handles(NULL);
2118 JNIHandleBlock::release_block(block);
2119 }
2120
2121 if (free_handle_block() != NULL) {
2122 JNIHandleBlock* block = free_handle_block();
2123 set_free_handle_block(NULL);
2124 JNIHandleBlock::release_block(block);
2125 }
2126
2127 // These have to be removed while this is still a valid thread.
2128 remove_stack_guard_pages();
2129
2130 if (UseTLAB) {
2131 tlab().retire();
2132 }
2133
2134 BarrierSet::barrier_set()->on_thread_detach(this);
2135
2136 Threads::remove(this, is_daemon);
2137 this->smr_delete();
2138 }
2139
2140 JavaThread* JavaThread::active() {
2141 Thread* thread = Thread::current();
2142 if (thread->is_Java_thread()) {
2143 return (JavaThread*) thread;
2144 } else {
2145 assert(thread->is_VM_thread(), "this must be a vm thread");
2146 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2147 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2148 assert(ret->is_Java_thread(), "must be a Java thread");
2149 return ret;
2150 }
2151 }
2152
2153 bool JavaThread::is_lock_owned(address adr) const {
2154 if (Thread::is_lock_owned(adr)) return true;
2155
2156 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2157 if (chunk->contains(adr)) return true;
2158 }
2159
2160 return false;
2161 }
2162
2163
2164 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2165 chunk->set_next(monitor_chunks());
2166 set_monitor_chunks(chunk);
2167 }
2168
2169 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2170 guarantee(monitor_chunks() != NULL, "must be non empty");
2171 if (monitor_chunks() == chunk) {
2172 set_monitor_chunks(chunk->next());
2173 } else {
2174 MonitorChunk* prev = monitor_chunks();
2175 while (prev->next() != chunk) prev = prev->next();
2176 prev->set_next(chunk->next());
2177 }
2178 }
2179
2180 // JVM support.
2181
2182 // Note: this function shouldn't block if it's called in
2183 // _thread_in_native_trans state (such as from
2184 // check_special_condition_for_native_trans()).
2185 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2186
2187 if (has_last_Java_frame() && has_async_condition()) {
2188 // If we are at a polling page safepoint (not a poll return)
2189 // then we must defer async exception because live registers
2190 // will be clobbered by the exception path. Poll return is
2191 // ok because the call we a returning from already collides
2192 // with exception handling registers and so there is no issue.
2193 // (The exception handling path kills call result registers but
2194 // this is ok since the exception kills the result anyway).
2195
2196 if (is_at_poll_safepoint()) {
2197 // if the code we are returning to has deoptimized we must defer
2198 // the exception otherwise live registers get clobbered on the
2199 // exception path before deoptimization is able to retrieve them.
2200 //
2201 RegisterMap map(this, false);
2202 frame caller_fr = last_frame().sender(&map);
2203 assert(caller_fr.is_compiled_frame(), "what?");
2204 if (caller_fr.is_deoptimized_frame()) {
2205 log_info(exceptions)("deferred async exception at compiled safepoint");
2206 return;
2207 }
2208 }
2209 }
2210
2211 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2212 if (condition == _no_async_condition) {
2213 // Conditions have changed since has_special_runtime_exit_condition()
2214 // was called:
2215 // - if we were here only because of an external suspend request,
2216 // then that was taken care of above (or cancelled) so we are done
2217 // - if we were here because of another async request, then it has
2218 // been cleared between the has_special_runtime_exit_condition()
2219 // and now so again we are done
2220 return;
2221 }
2222
2223 // Check for pending async. exception
2224 if (_pending_async_exception != NULL) {
2225 // Only overwrite an already pending exception, if it is not a threadDeath.
2226 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2227
2228 // We cannot call Exceptions::_throw(...) here because we cannot block
2229 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2230
2231 LogTarget(Info, exceptions) lt;
2232 if (lt.is_enabled()) {
2233 ResourceMark rm;
2234 LogStream ls(lt);
2235 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2236 if (has_last_Java_frame()) {
2237 frame f = last_frame();
2238 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2239 }
2240 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2241 }
2242 _pending_async_exception = NULL;
2243 clear_has_async_exception();
2244 }
2245 }
2246
2247 if (check_unsafe_error &&
2248 condition == _async_unsafe_access_error && !has_pending_exception()) {
2249 condition = _no_async_condition; // done
2250 switch (thread_state()) {
2251 case _thread_in_vm: {
2252 JavaThread* THREAD = this;
2253 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2254 }
2255 case _thread_in_native: {
2256 ThreadInVMfromNative tiv(this);
2257 JavaThread* THREAD = this;
2258 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2259 }
2260 case _thread_in_Java: {
2261 ThreadInVMfromJava tiv(this);
2262 JavaThread* THREAD = this;
2263 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2264 }
2265 default:
2266 ShouldNotReachHere();
2267 }
2268 }
2269
2270 assert(condition == _no_async_condition || has_pending_exception() ||
2271 (!check_unsafe_error && condition == _async_unsafe_access_error),
2272 "must have handled the async condition, if no exception");
2273 }
2274
2275 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2276 //
2277 // Check for pending external suspend.
2278 // If JNIEnv proxies are allowed, don't self-suspend if the target
2279 // thread is not the current thread. In older versions of jdbx, jdbx
2280 // threads could call into the VM with another thread's JNIEnv so we
2281 // can be here operating on behalf of a suspended thread (4432884).
2282 bool do_self_suspend = is_external_suspend_with_lock();
2283 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2284 frame_anchor()->make_walkable(this);
2285 java_suspend_self_with_safepoint_check();
2286 }
2287
2288 // We might be here for reasons in addition to the self-suspend request
2289 // so check for other async requests.
2290 if (check_asyncs) {
2291 check_and_handle_async_exceptions();
2292 }
2293
2294 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2295 }
2296
2297 void JavaThread::send_thread_stop(oop java_throwable) {
2298 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2299 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2300 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2301
2302 // Do not throw asynchronous exceptions against the compiler thread
2303 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2304 if (!can_call_java()) return;
2305
2306 {
2307 // Actually throw the Throwable against the target Thread - however
2308 // only if there is no thread death exception installed already.
2309 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2310 // If the topmost frame is a runtime stub, then we are calling into
2311 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2312 // must deoptimize the caller before continuing, as the compiled exception handler table
2313 // may not be valid
2314 if (has_last_Java_frame()) {
2315 frame f = last_frame();
2316 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2317 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2318 RegisterMap reg_map(this, UseBiasedLocking);
2319 frame compiled_frame = f.sender(®_map);
2320 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2321 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2322 }
2323 }
2324 }
2325
2326 // Set async. pending exception in thread.
2327 set_pending_async_exception(java_throwable);
2328
2329 if (log_is_enabled(Info, exceptions)) {
2330 ResourceMark rm;
2331 log_info(exceptions)("Pending Async. exception installed of type: %s",
2332 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2333 }
2334 // for AbortVMOnException flag
2335 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2336 }
2337 }
2338
2339
2340 // Interrupt thread so it will wake up from a potential wait()
2341 Thread::interrupt(this);
2342 }
2343
2344 // External suspension mechanism.
2345 //
2346 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2347 // to any VM_locks and it is at a transition
2348 // Self-suspension will happen on the transition out of the vm.
2349 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2350 //
2351 // Guarantees on return:
2352 // + Target thread will not execute any new bytecode (that's why we need to
2353 // force a safepoint)
2354 // + Target thread will not enter any new monitors
2355 //
2356 void JavaThread::java_suspend() {
2357 ThreadsListHandle tlh;
2358 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2359 return;
2360 }
2361
2362 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2363 if (!is_external_suspend()) {
2364 // a racing resume has cancelled us; bail out now
2365 return;
2366 }
2367
2368 // suspend is done
2369 uint32_t debug_bits = 0;
2370 // Warning: is_ext_suspend_completed() may temporarily drop the
2371 // SR_lock to allow the thread to reach a stable thread state if
2372 // it is currently in a transient thread state.
2373 if (is_ext_suspend_completed(false /* !called_by_wait */,
2374 SuspendRetryDelay, &debug_bits)) {
2375 return;
2376 }
2377 }
2378
2379 if (Thread::current() == this) {
2380 // Safely self-suspend.
2381 // If we don't do this explicitly it will implicitly happen
2382 // before we transition back to Java, and on some other thread-state
2383 // transition paths, but not as we exit a JVM TI SuspendThread call.
2384 // As SuspendThread(current) must not return (until resumed) we must
2385 // self-suspend here.
2386 ThreadBlockInVM tbivm(this);
2387 java_suspend_self();
2388 } else {
2389 VM_ThreadSuspend vm_suspend;
2390 VMThread::execute(&vm_suspend);
2391 }
2392 }
2393
2394 // Part II of external suspension.
2395 // A JavaThread self suspends when it detects a pending external suspend
2396 // request. This is usually on transitions. It is also done in places
2397 // where continuing to the next transition would surprise the caller,
2398 // e.g., monitor entry.
2399 //
2400 // Returns the number of times that the thread self-suspended.
2401 //
2402 // Note: DO NOT call java_suspend_self() when you just want to block current
2403 // thread. java_suspend_self() is the second stage of cooperative
2404 // suspension for external suspend requests and should only be used
2405 // to complete an external suspend request.
2406 //
2407 int JavaThread::java_suspend_self() {
2408 assert(thread_state() == _thread_blocked, "wrong state for java_suspend_self()");
2409 int ret = 0;
2410
2411 // we are in the process of exiting so don't suspend
2412 if (is_exiting()) {
2413 clear_external_suspend();
2414 return ret;
2415 }
2416
2417 assert(_anchor.walkable() ||
2418 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2419 "must have walkable stack");
2420
2421 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2422
2423 assert(!this->is_ext_suspended(),
2424 "a thread trying to self-suspend should not already be suspended");
2425
2426 if (this->is_suspend_equivalent()) {
2427 // If we are self-suspending as a result of the lifting of a
2428 // suspend equivalent condition, then the suspend_equivalent
2429 // flag is not cleared until we set the ext_suspended flag so
2430 // that wait_for_ext_suspend_completion() returns consistent
2431 // results.
2432 this->clear_suspend_equivalent();
2433 }
2434
2435 // A racing resume may have cancelled us before we grabbed SR_lock
2436 // above. Or another external suspend request could be waiting for us
2437 // by the time we return from SR_lock()->wait(). The thread
2438 // that requested the suspension may already be trying to walk our
2439 // stack and if we return now, we can change the stack out from under
2440 // it. This would be a "bad thing (TM)" and cause the stack walker
2441 // to crash. We stay self-suspended until there are no more pending
2442 // external suspend requests.
2443 while (is_external_suspend()) {
2444 ret++;
2445 this->set_ext_suspended();
2446
2447 // _ext_suspended flag is cleared by java_resume()
2448 while (is_ext_suspended()) {
2449 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2450 }
2451 }
2452 return ret;
2453 }
2454
2455 // Helper routine to set up the correct thread state before calling java_suspend_self.
2456 // This is called when regular thread-state transition helpers can't be used because
2457 // we can be in various states, in particular _thread_in_native_trans.
2458 // Because this thread is external suspended the safepoint code will count it as at
2459 // a safepoint, regardless of what its actual current thread-state is. But
2460 // is_ext_suspend_completed() may be waiting to see a thread transition from
2461 // _thread_in_native_trans to _thread_blocked. So we set the thread state directly
2462 // to _thread_blocked. The problem with setting thread state directly is that a
2463 // safepoint could happen just after java_suspend_self() returns after being resumed,
2464 // and the VM thread will see the _thread_blocked state. So we must check for a safepoint
2465 // after restoring the state to make sure we won't leave while a safepoint is in progress.
2466 // However, not all initial-states are allowed when performing a safepoint check, as we
2467 // should never be blocking at a safepoint whilst in those states. Of these 'bad' states
2468 // only _thread_in_native is possible when executing this code (based on our two callers).
2469 // A thread that is _thread_in_native is already safepoint-safe and so it doesn't matter
2470 // whether the VMThread sees the _thread_blocked state, or the _thread_in_native state,
2471 // and so we don't need the explicit safepoint check.
2472
2473 void JavaThread::java_suspend_self_with_safepoint_check() {
2474 assert(this == Thread::current(), "invariant");
2475 JavaThreadState state = thread_state();
2476 set_thread_state(_thread_blocked);
2477 java_suspend_self();
2478 set_thread_state_fence(state);
2479 // Since we are not using a regular thread-state transition helper here,
2480 // we must manually emit the instruction barrier after leaving a safe state.
2481 OrderAccess::cross_modify_fence();
2482 if (state != _thread_in_native) {
2483 SafepointMechanism::block_if_requested(this);
2484 }
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 thread->java_suspend_self_with_safepoint_check();
2519 } else {
2520 SafepointMechanism::block_if_requested(curJT);
2521 }
2522
2523 if (thread->is_deopt_suspend()) {
2524 thread->clear_deopt_suspend();
2525 RegisterMap map(thread, false);
2526 frame f = thread->last_frame();
2527 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2528 f = f.sender(&map);
2529 }
2530 if (f.id() == thread->must_deopt_id()) {
2531 thread->clear_must_deopt_id();
2532 f.deoptimize(thread);
2533 } else {
2534 fatal("missed deoptimization!");
2535 }
2536 }
2537
2538 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2539 }
2540
2541 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2542 // progress or when _suspend_flags is non-zero.
2543 // Current thread needs to self-suspend if there is a suspend request and/or
2544 // block if a safepoint is in progress.
2545 // Also check for pending async exception (not including unsafe access error).
2546 // Note only the native==>VM/Java barriers can call this function and when
2547 // thread state is _thread_in_native_trans.
2548 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2549 check_safepoint_and_suspend_for_native_trans(thread);
2550
2551 if (thread->has_async_exception()) {
2552 // We are in _thread_in_native_trans state, don't handle unsafe
2553 // access error since that may block.
2554 thread->check_and_handle_async_exceptions(false);
2555 }
2556 }
2557
2558 // This is a variant of the normal
2559 // check_special_condition_for_native_trans with slightly different
2560 // semantics for use by critical native wrappers. It does all the
2561 // normal checks but also performs the transition back into
2562 // thread_in_Java state. This is required so that critical natives
2563 // can potentially block and perform a GC if they are the last thread
2564 // exiting the GCLocker.
2565 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2566 check_special_condition_for_native_trans(thread);
2567
2568 // Finish the transition
2569 thread->set_thread_state(_thread_in_Java);
2570
2571 if (thread->do_critical_native_unlock()) {
2572 ThreadInVMfromJavaNoAsyncException tiv(thread);
2573 GCLocker::unlock_critical(thread);
2574 thread->clear_critical_native_unlock();
2575 }
2576 }
2577
2578 // We need to guarantee the Threads_lock here, since resumes are not
2579 // allowed during safepoint synchronization
2580 // Can only resume from an external suspension
2581 void JavaThread::java_resume() {
2582 assert_locked_or_safepoint(Threads_lock);
2583
2584 // Sanity check: thread is gone, has started exiting or the thread
2585 // was not externally suspended.
2586 ThreadsListHandle tlh;
2587 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2588 return;
2589 }
2590
2591 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2592
2593 clear_external_suspend();
2594
2595 if (is_ext_suspended()) {
2596 clear_ext_suspended();
2597 SR_lock()->notify_all();
2598 }
2599 }
2600
2601 size_t JavaThread::_stack_red_zone_size = 0;
2602 size_t JavaThread::_stack_yellow_zone_size = 0;
2603 size_t JavaThread::_stack_reserved_zone_size = 0;
2604 size_t JavaThread::_stack_shadow_zone_size = 0;
2605
2606 void JavaThread::create_stack_guard_pages() {
2607 if (!os::uses_stack_guard_pages() ||
2608 _stack_guard_state != stack_guard_unused ||
2609 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2610 log_info(os, thread)("Stack guard page creation for thread "
2611 UINTX_FORMAT " disabled", os::current_thread_id());
2612 return;
2613 }
2614 address low_addr = stack_end();
2615 size_t len = stack_guard_zone_size();
2616
2617 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2618 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2619
2620 int must_commit = os::must_commit_stack_guard_pages();
2621 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2622
2623 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2624 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2625 return;
2626 }
2627
2628 if (os::guard_memory((char *) low_addr, len)) {
2629 _stack_guard_state = stack_guard_enabled;
2630 } else {
2631 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2632 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2633 if (os::uncommit_memory((char *) low_addr, len)) {
2634 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2635 }
2636 return;
2637 }
2638
2639 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2640 PTR_FORMAT "-" PTR_FORMAT ".",
2641 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2642 }
2643
2644 void JavaThread::remove_stack_guard_pages() {
2645 assert(Thread::current() == this, "from different thread");
2646 if (_stack_guard_state == stack_guard_unused) return;
2647 address low_addr = stack_end();
2648 size_t len = stack_guard_zone_size();
2649
2650 if (os::must_commit_stack_guard_pages()) {
2651 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2652 _stack_guard_state = stack_guard_unused;
2653 } else {
2654 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2655 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2656 return;
2657 }
2658 } else {
2659 if (_stack_guard_state == stack_guard_unused) return;
2660 if (os::unguard_memory((char *) low_addr, len)) {
2661 _stack_guard_state = stack_guard_unused;
2662 } else {
2663 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2664 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2665 return;
2666 }
2667 }
2668
2669 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2670 PTR_FORMAT "-" PTR_FORMAT ".",
2671 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2672 }
2673
2674 void JavaThread::enable_stack_reserved_zone() {
2675 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state");
2676
2677 // The base notation is from the stack's point of view, growing downward.
2678 // We need to adjust it to work correctly with guard_memory()
2679 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2680
2681 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2682 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2683
2684 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2685 _stack_guard_state = stack_guard_enabled;
2686 } else {
2687 warning("Attempt to guard stack reserved zone failed.");
2688 }
2689 enable_register_stack_guard();
2690 }
2691
2692 void JavaThread::disable_stack_reserved_zone() {
2693 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state");
2694
2695 // Simply return if called for a thread that does not use guard pages.
2696 if (_stack_guard_state != stack_guard_enabled) return;
2697
2698 // The base notation is from the stack's point of view, growing downward.
2699 // We need to adjust it to work correctly with guard_memory()
2700 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2701
2702 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2703 _stack_guard_state = stack_guard_reserved_disabled;
2704 } else {
2705 warning("Attempt to unguard stack reserved zone failed.");
2706 }
2707 disable_register_stack_guard();
2708 }
2709
2710 void JavaThread::enable_stack_yellow_reserved_zone() {
2711 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2712 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2713
2714 // The base notation is from the stacks point of view, growing downward.
2715 // We need to adjust it to work correctly with guard_memory()
2716 address base = stack_red_zone_base();
2717
2718 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2719 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2720
2721 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2722 _stack_guard_state = stack_guard_enabled;
2723 } else {
2724 warning("Attempt to guard stack yellow zone failed.");
2725 }
2726 enable_register_stack_guard();
2727 }
2728
2729 void JavaThread::disable_stack_yellow_reserved_zone() {
2730 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2731 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2732
2733 // Simply return if called for a thread that does not use guard pages.
2734 if (_stack_guard_state == stack_guard_unused) return;
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 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2741 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2742 } else {
2743 warning("Attempt to unguard stack yellow zone failed.");
2744 }
2745 disable_register_stack_guard();
2746 }
2747
2748 void JavaThread::enable_stack_red_zone() {
2749 // The base notation is from the stacks point of view, growing downward.
2750 // We need to adjust it to work correctly with guard_memory()
2751 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2752 address base = stack_red_zone_base() - stack_red_zone_size();
2753
2754 guarantee(base < stack_base(), "Error calculating stack red zone");
2755 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2756
2757 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2758 warning("Attempt to guard stack red zone failed.");
2759 }
2760 }
2761
2762 void JavaThread::disable_stack_red_zone() {
2763 // The base notation is from the stacks point of view, growing downward.
2764 // We need to adjust it to work correctly with guard_memory()
2765 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2766 address base = stack_red_zone_base() - stack_red_zone_size();
2767 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2768 warning("Attempt to unguard stack red zone failed.");
2769 }
2770 }
2771
2772 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2773 // ignore is there is no stack
2774 if (!has_last_Java_frame()) return;
2775 // traverse the stack frames. Starts from top frame.
2776 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2777 frame* fr = fst.current();
2778 f(fr, fst.register_map());
2779 }
2780 }
2781
2782
2783 #ifndef PRODUCT
2784 // Deoptimization
2785 // Function for testing deoptimization
2786 void JavaThread::deoptimize() {
2787 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2788 StackFrameStream fst(this, UseBiasedLocking);
2789 bool deopt = false; // Dump stack only if a deopt actually happens.
2790 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2791 // Iterate over all frames in the thread and deoptimize
2792 for (; !fst.is_done(); fst.next()) {
2793 if (fst.current()->can_be_deoptimized()) {
2794
2795 if (only_at) {
2796 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2797 // consists of comma or carriage return separated numbers so
2798 // search for the current bci in that string.
2799 address pc = fst.current()->pc();
2800 nmethod* nm = (nmethod*) fst.current()->cb();
2801 ScopeDesc* sd = nm->scope_desc_at(pc);
2802 char buffer[8];
2803 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2804 size_t len = strlen(buffer);
2805 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2806 while (found != NULL) {
2807 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2808 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2809 // Check that the bci found is bracketed by terminators.
2810 break;
2811 }
2812 found = strstr(found + 1, buffer);
2813 }
2814 if (!found) {
2815 continue;
2816 }
2817 }
2818
2819 if (DebugDeoptimization && !deopt) {
2820 deopt = true; // One-time only print before deopt
2821 tty->print_cr("[BEFORE Deoptimization]");
2822 trace_frames();
2823 trace_stack();
2824 }
2825 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2826 }
2827 }
2828
2829 if (DebugDeoptimization && deopt) {
2830 tty->print_cr("[AFTER Deoptimization]");
2831 trace_frames();
2832 }
2833 }
2834
2835
2836 // Make zombies
2837 void JavaThread::make_zombies() {
2838 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2839 if (fst.current()->can_be_deoptimized()) {
2840 // it is a Java nmethod
2841 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2842 nm->make_not_entrant();
2843 }
2844 }
2845 }
2846 #endif // PRODUCT
2847
2848
2849 void JavaThread::deoptimized_wrt_marked_nmethods() {
2850 if (!has_last_Java_frame()) return;
2851 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2852 StackFrameStream fst(this, UseBiasedLocking);
2853 for (; !fst.is_done(); fst.next()) {
2854 if (fst.current()->should_be_deoptimized()) {
2855 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2856 }
2857 }
2858 }
2859
2860
2861 // If the caller is a NamedThread, then remember, in the current scope,
2862 // the given JavaThread in its _processed_thread field.
2863 class RememberProcessedThread: public StackObj {
2864 NamedThread* _cur_thr;
2865 public:
2866 RememberProcessedThread(JavaThread* jthr) {
2867 Thread* thread = Thread::current();
2868 if (thread->is_Named_thread()) {
2869 _cur_thr = (NamedThread *)thread;
2870 _cur_thr->set_processed_thread(jthr);
2871 } else {
2872 _cur_thr = NULL;
2873 }
2874 }
2875
2876 ~RememberProcessedThread() {
2877 if (_cur_thr) {
2878 _cur_thr->set_processed_thread(NULL);
2879 }
2880 }
2881 };
2882
2883 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2884 // Verify that the deferred card marks have been flushed.
2885 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2886
2887 // Traverse the GCHandles
2888 Thread::oops_do(f, cf);
2889
2890 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2891 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2892
2893 if (has_last_Java_frame()) {
2894 // Record JavaThread to GC thread
2895 RememberProcessedThread rpt(this);
2896
2897 // traverse the registered growable array
2898 if (_array_for_gc != NULL) {
2899 for (int index = 0; index < _array_for_gc->length(); index++) {
2900 f->do_oop(_array_for_gc->adr_at(index));
2901 }
2902 }
2903
2904 // Traverse the monitor chunks
2905 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2906 chunk->oops_do(f);
2907 }
2908
2909 // Traverse the execution stack
2910 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2911 fst.current()->oops_do(f, cf, fst.register_map());
2912 }
2913 }
2914
2915 // callee_target is never live across a gc point so NULL it here should
2916 // it still contain a methdOop.
2917
2918 set_callee_target(NULL);
2919
2920 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2921 // If we have deferred set_locals there might be oops waiting to be
2922 // written
2923 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2924 if (list != NULL) {
2925 for (int i = 0; i < list->length(); i++) {
2926 list->at(i)->oops_do(f);
2927 }
2928 }
2929
2930 // Traverse instance variables at the end since the GC may be moving things
2931 // around using this function
2932 f->do_oop((oop*) &_threadObj);
2933 f->do_oop((oop*) &_vm_result);
2934 f->do_oop((oop*) &_exception_oop);
2935 f->do_oop((oop*) &_pending_async_exception);
2936
2937 if (jvmti_thread_state() != NULL) {
2938 jvmti_thread_state()->oops_do(f);
2939 }
2940 }
2941
2942 #ifdef ASSERT
2943 void JavaThread::verify_states_for_handshake() {
2944 // This checks that the thread has a correct frame state during a handshake.
2945 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2946 (has_last_Java_frame() && java_call_counter() > 0),
2947 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
2948 has_last_Java_frame(), java_call_counter());
2949 }
2950 #endif
2951
2952 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2953 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2954 (has_last_Java_frame() && java_call_counter() > 0),
2955 "unexpected frame info: has_last_frame=%d, java_call_counter=%d",
2956 has_last_Java_frame(), java_call_counter());
2957
2958 if (has_last_Java_frame()) {
2959 // Traverse the execution stack
2960 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2961 fst.current()->nmethods_do(cf);
2962 }
2963 }
2964 }
2965
2966 void JavaThread::metadata_do(MetadataClosure* f) {
2967 if (has_last_Java_frame()) {
2968 // Traverse the execution stack to call f() on the methods in the stack
2969 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2970 fst.current()->metadata_do(f);
2971 }
2972 } else if (is_Compiler_thread()) {
2973 // need to walk ciMetadata in current compile tasks to keep alive.
2974 CompilerThread* ct = (CompilerThread*)this;
2975 if (ct->env() != NULL) {
2976 ct->env()->metadata_do(f);
2977 }
2978 CompileTask* task = ct->task();
2979 if (task != NULL) {
2980 task->metadata_do(f);
2981 }
2982 }
2983 }
2984
2985 // Printing
2986 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2987 switch (_thread_state) {
2988 case _thread_uninitialized: return "_thread_uninitialized";
2989 case _thread_new: return "_thread_new";
2990 case _thread_new_trans: return "_thread_new_trans";
2991 case _thread_in_native: return "_thread_in_native";
2992 case _thread_in_native_trans: return "_thread_in_native_trans";
2993 case _thread_in_vm: return "_thread_in_vm";
2994 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2995 case _thread_in_Java: return "_thread_in_Java";
2996 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2997 case _thread_blocked: return "_thread_blocked";
2998 case _thread_blocked_trans: return "_thread_blocked_trans";
2999 default: return "unknown thread state";
3000 }
3001 }
3002
3003 #ifndef PRODUCT
3004 void JavaThread::print_thread_state_on(outputStream *st) const {
3005 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
3006 };
3007 void JavaThread::print_thread_state() const {
3008 print_thread_state_on(tty);
3009 }
3010 #endif // PRODUCT
3011
3012 // Called by Threads::print() for VM_PrintThreads operation
3013 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
3014 st->print_raw("\"");
3015 st->print_raw(get_thread_name());
3016 st->print_raw("\" ");
3017 oop thread_oop = threadObj();
3018 if (thread_oop != NULL) {
3019 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
3020 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
3021 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
3022 }
3023 Thread::print_on(st, print_extended_info);
3024 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
3025 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
3026 if (thread_oop != NULL) {
3027 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3028 }
3029 #ifndef PRODUCT
3030 _safepoint_state->print_on(st);
3031 #endif // PRODUCT
3032 if (is_Compiler_thread()) {
3033 CompileTask *task = ((CompilerThread*)this)->task();
3034 if (task != NULL) {
3035 st->print(" Compiling: ");
3036 task->print(st, NULL, true, false);
3037 } else {
3038 st->print(" No compile task");
3039 }
3040 st->cr();
3041 }
3042 }
3043
3044 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3045 st->print("%s", get_thread_name_string(buf, buflen));
3046 }
3047
3048 // Called by fatal error handler. The difference between this and
3049 // JavaThread::print() is that we can't grab lock or allocate memory.
3050 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3051 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3052 oop thread_obj = threadObj();
3053 if (thread_obj != NULL) {
3054 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3055 }
3056 st->print(" [");
3057 st->print("%s", _get_thread_state_name(_thread_state));
3058 if (osthread()) {
3059 st->print(", id=%d", osthread()->thread_id());
3060 }
3061 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3062 p2i(stack_end()), p2i(stack_base()));
3063 st->print("]");
3064
3065 ThreadsSMRSupport::print_info_on(this, st);
3066 return;
3067 }
3068
3069 // Verification
3070
3071 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3072
3073 void JavaThread::verify() {
3074 // Verify oops in the thread.
3075 oops_do(&VerifyOopClosure::verify_oop, NULL);
3076
3077 // Verify the stack frames.
3078 frames_do(frame_verify);
3079 }
3080
3081 // CR 6300358 (sub-CR 2137150)
3082 // Most callers of this method assume that it can't return NULL but a
3083 // thread may not have a name whilst it is in the process of attaching to
3084 // the VM - see CR 6412693, and there are places where a JavaThread can be
3085 // seen prior to having it's threadObj set (eg JNI attaching threads and
3086 // if vm exit occurs during initialization). These cases can all be accounted
3087 // for such that this method never returns NULL.
3088 const char* JavaThread::get_thread_name() const {
3089 #ifdef ASSERT
3090 // early safepoints can hit while current thread does not yet have TLS
3091 if (!SafepointSynchronize::is_at_safepoint()) {
3092 Thread *cur = Thread::current();
3093 if (!(cur->is_Java_thread() && cur == this)) {
3094 // Current JavaThreads are allowed to get their own name without
3095 // the Threads_lock.
3096 assert_locked_or_safepoint(Threads_lock);
3097 }
3098 }
3099 #endif // ASSERT
3100 return get_thread_name_string();
3101 }
3102
3103 // Returns a non-NULL representation of this thread's name, or a suitable
3104 // descriptive string if there is no set name
3105 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3106 const char* name_str;
3107 oop thread_obj = threadObj();
3108 if (thread_obj != NULL) {
3109 oop name = java_lang_Thread::name(thread_obj);
3110 if (name != NULL) {
3111 if (buf == NULL) {
3112 name_str = java_lang_String::as_utf8_string(name);
3113 } else {
3114 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3115 }
3116 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3117 name_str = "<no-name - thread is attaching>";
3118 } else {
3119 name_str = Thread::name();
3120 }
3121 } else {
3122 name_str = Thread::name();
3123 }
3124 assert(name_str != NULL, "unexpected NULL thread name");
3125 return name_str;
3126 }
3127
3128
3129 const char* JavaThread::get_threadgroup_name() const {
3130 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3131 oop thread_obj = threadObj();
3132 if (thread_obj != NULL) {
3133 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3134 if (thread_group != NULL) {
3135 // ThreadGroup.name can be null
3136 return java_lang_ThreadGroup::name(thread_group);
3137 }
3138 }
3139 return NULL;
3140 }
3141
3142 const char* JavaThread::get_parent_name() const {
3143 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3144 oop thread_obj = threadObj();
3145 if (thread_obj != NULL) {
3146 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3147 if (thread_group != NULL) {
3148 oop parent = java_lang_ThreadGroup::parent(thread_group);
3149 if (parent != NULL) {
3150 // ThreadGroup.name can be null
3151 return java_lang_ThreadGroup::name(parent);
3152 }
3153 }
3154 }
3155 return NULL;
3156 }
3157
3158 ThreadPriority JavaThread::java_priority() const {
3159 oop thr_oop = threadObj();
3160 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3161 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3162 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3163 return priority;
3164 }
3165
3166 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3167
3168 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3169 // Link Java Thread object <-> C++ Thread
3170
3171 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3172 // and put it into a new Handle. The Handle "thread_oop" can then
3173 // be used to pass the C++ thread object to other methods.
3174
3175 // Set the Java level thread object (jthread) field of the
3176 // new thread (a JavaThread *) to C++ thread object using the
3177 // "thread_oop" handle.
3178
3179 // Set the thread field (a JavaThread *) of the
3180 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3181
3182 Handle thread_oop(Thread::current(),
3183 JNIHandles::resolve_non_null(jni_thread));
3184 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3185 "must be initialized");
3186 set_threadObj(thread_oop());
3187 java_lang_Thread::set_thread(thread_oop(), this);
3188
3189 if (prio == NoPriority) {
3190 prio = java_lang_Thread::priority(thread_oop());
3191 assert(prio != NoPriority, "A valid priority should be present");
3192 }
3193
3194 // Push the Java priority down to the native thread; needs Threads_lock
3195 Thread::set_priority(this, prio);
3196
3197 // Add the new thread to the Threads list and set it in motion.
3198 // We must have threads lock in order to call Threads::add.
3199 // It is crucial that we do not block before the thread is
3200 // added to the Threads list for if a GC happens, then the java_thread oop
3201 // will not be visited by GC.
3202 Threads::add(this);
3203 }
3204
3205 oop JavaThread::current_park_blocker() {
3206 // Support for JSR-166 locks
3207 oop thread_oop = threadObj();
3208 if (thread_oop != NULL &&
3209 JDK_Version::current().supports_thread_park_blocker()) {
3210 return java_lang_Thread::park_blocker(thread_oop);
3211 }
3212 return NULL;
3213 }
3214
3215
3216 void JavaThread::print_stack_on(outputStream* st) {
3217 if (!has_last_Java_frame()) return;
3218 ResourceMark rm;
3219 HandleMark hm;
3220
3221 RegisterMap reg_map(this);
3222 vframe* start_vf = last_java_vframe(®_map);
3223 int count = 0;
3224 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3225 if (f->is_java_frame()) {
3226 javaVFrame* jvf = javaVFrame::cast(f);
3227 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3228
3229 // Print out lock information
3230 if (JavaMonitorsInStackTrace) {
3231 jvf->print_lock_info_on(st, count);
3232 }
3233 } else {
3234 // Ignore non-Java frames
3235 }
3236
3237 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3238 count++;
3239 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3240 }
3241 }
3242
3243
3244 // JVMTI PopFrame support
3245 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3246 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3247 if (in_bytes(size_in_bytes) != 0) {
3248 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3249 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3250 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3251 }
3252 }
3253
3254 void* JavaThread::popframe_preserved_args() {
3255 return _popframe_preserved_args;
3256 }
3257
3258 ByteSize JavaThread::popframe_preserved_args_size() {
3259 return in_ByteSize(_popframe_preserved_args_size);
3260 }
3261
3262 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3263 int sz = in_bytes(popframe_preserved_args_size());
3264 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3265 return in_WordSize(sz / wordSize);
3266 }
3267
3268 void JavaThread::popframe_free_preserved_args() {
3269 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3270 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3271 _popframe_preserved_args = NULL;
3272 _popframe_preserved_args_size = 0;
3273 }
3274
3275 #ifndef PRODUCT
3276
3277 void JavaThread::trace_frames() {
3278 tty->print_cr("[Describe stack]");
3279 int frame_no = 1;
3280 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3281 tty->print(" %d. ", frame_no++);
3282 fst.current()->print_value_on(tty, this);
3283 tty->cr();
3284 }
3285 }
3286
3287 class PrintAndVerifyOopClosure: public OopClosure {
3288 protected:
3289 template <class T> inline void do_oop_work(T* p) {
3290 oop obj = RawAccess<>::oop_load(p);
3291 if (obj == NULL) return;
3292 tty->print(INTPTR_FORMAT ": ", p2i(p));
3293 if (oopDesc::is_oop_or_null(obj)) {
3294 if (obj->is_objArray()) {
3295 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3296 } else {
3297 obj->print();
3298 }
3299 } else {
3300 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3301 }
3302 tty->cr();
3303 }
3304 public:
3305 virtual void do_oop(oop* p) { do_oop_work(p); }
3306 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3307 };
3308
3309
3310 static void oops_print(frame* f, const RegisterMap *map) {
3311 PrintAndVerifyOopClosure print;
3312 f->print_value();
3313 f->oops_do(&print, NULL, (RegisterMap*)map);
3314 }
3315
3316 // Print our all the locations that contain oops and whether they are
3317 // valid or not. This useful when trying to find the oldest frame
3318 // where an oop has gone bad since the frame walk is from youngest to
3319 // oldest.
3320 void JavaThread::trace_oops() {
3321 tty->print_cr("[Trace oops]");
3322 frames_do(oops_print);
3323 }
3324
3325
3326 #ifdef ASSERT
3327 // Print or validate the layout of stack frames
3328 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3329 ResourceMark rm;
3330 PRESERVE_EXCEPTION_MARK;
3331 FrameValues values;
3332 int frame_no = 0;
3333 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3334 fst.current()->describe(values, ++frame_no);
3335 if (depth == frame_no) break;
3336 }
3337 if (validate_only) {
3338 values.validate();
3339 } else {
3340 tty->print_cr("[Describe stack layout]");
3341 values.print(this);
3342 }
3343 }
3344 #endif
3345
3346 void JavaThread::trace_stack_from(vframe* start_vf) {
3347 ResourceMark rm;
3348 int vframe_no = 1;
3349 for (vframe* f = start_vf; f; f = f->sender()) {
3350 if (f->is_java_frame()) {
3351 javaVFrame::cast(f)->print_activation(vframe_no++);
3352 } else {
3353 f->print();
3354 }
3355 if (vframe_no > StackPrintLimit) {
3356 tty->print_cr("...<more frames>...");
3357 return;
3358 }
3359 }
3360 }
3361
3362
3363 void JavaThread::trace_stack() {
3364 if (!has_last_Java_frame()) return;
3365 ResourceMark rm;
3366 HandleMark hm;
3367 RegisterMap reg_map(this);
3368 trace_stack_from(last_java_vframe(®_map));
3369 }
3370
3371
3372 #endif // PRODUCT
3373
3374
3375 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3376 assert(reg_map != NULL, "a map must be given");
3377 frame f = last_frame();
3378 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3379 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3380 }
3381 return NULL;
3382 }
3383
3384
3385 Klass* JavaThread::security_get_caller_class(int depth) {
3386 vframeStream vfst(this);
3387 vfst.security_get_caller_frame(depth);
3388 if (!vfst.at_end()) {
3389 return vfst.method()->method_holder();
3390 }
3391 return NULL;
3392 }
3393
3394 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3395 assert(thread->is_Compiler_thread(), "must be compiler thread");
3396 CompileBroker::compiler_thread_loop();
3397 }
3398
3399 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3400 NMethodSweeper::sweeper_loop();
3401 }
3402
3403 // Create a CompilerThread
3404 CompilerThread::CompilerThread(CompileQueue* queue,
3405 CompilerCounters* counters)
3406 : JavaThread(&compiler_thread_entry) {
3407 _env = NULL;
3408 _log = NULL;
3409 _task = NULL;
3410 _queue = queue;
3411 _counters = counters;
3412 _buffer_blob = NULL;
3413 _compiler = NULL;
3414
3415 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3416 resource_area()->bias_to(mtCompiler);
3417
3418 #ifndef PRODUCT
3419 _ideal_graph_printer = NULL;
3420 #endif
3421 }
3422
3423 CompilerThread::~CompilerThread() {
3424 // Delete objects which were allocated on heap.
3425 delete _counters;
3426 }
3427
3428 bool CompilerThread::can_call_java() const {
3429 return _compiler != NULL && _compiler->is_jvmci();
3430 }
3431
3432 // Create sweeper thread
3433 CodeCacheSweeperThread::CodeCacheSweeperThread()
3434 : JavaThread(&sweeper_thread_entry) {
3435 _scanned_compiled_method = NULL;
3436 }
3437
3438 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3439 JavaThread::oops_do(f, cf);
3440 if (_scanned_compiled_method != NULL && cf != NULL) {
3441 // Safepoints can occur when the sweeper is scanning an nmethod so
3442 // process it here to make sure it isn't unloaded in the middle of
3443 // a scan.
3444 cf->do_code_blob(_scanned_compiled_method);
3445 }
3446 }
3447
3448 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3449 JavaThread::nmethods_do(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
3459 // ======= Threads ========
3460
3461 // The Threads class links together all active threads, and provides
3462 // operations over all threads. It is protected by the Threads_lock,
3463 // which is also used in other global contexts like safepointing.
3464 // ThreadsListHandles are used to safely perform operations on one
3465 // or more threads without the risk of the thread exiting during the
3466 // operation.
3467 //
3468 // Note: The Threads_lock is currently more widely used than we
3469 // would like. We are actively migrating Threads_lock uses to other
3470 // mechanisms in order to reduce Threads_lock contention.
3471
3472 JavaThread* Threads::_thread_list = NULL;
3473 int Threads::_number_of_threads = 0;
3474 int Threads::_number_of_non_daemon_threads = 0;
3475 int Threads::_return_code = 0;
3476 uintx Threads::_thread_claim_token = 1; // Never zero.
3477 size_t JavaThread::_stack_size_at_create = 0;
3478
3479 #ifdef ASSERT
3480 bool Threads::_vm_complete = false;
3481 #endif
3482
3483 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3484 Prefetch::read((void*)addr, prefetch_interval);
3485 return *addr;
3486 }
3487
3488 // Possibly the ugliest for loop the world has seen. C++ does not allow
3489 // multiple types in the declaration section of the for loop. In this case
3490 // we are only dealing with pointers and hence can cast them. It looks ugly
3491 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3492 #define DO_JAVA_THREADS(LIST, X) \
3493 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3494 *MACRO_list = (JavaThread*)(LIST), \
3495 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3496 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3497 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3498 MACRO_current_p != MACRO_end; \
3499 MACRO_current_p++, \
3500 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3501
3502 // All JavaThreads
3503 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3504
3505 // All NonJavaThreads (i.e., every non-JavaThread in the system).
3506 void Threads::non_java_threads_do(ThreadClosure* tc) {
3507 NoSafepointVerifier nsv(!SafepointSynchronize::is_at_safepoint(), false);
3508 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
3509 tc->do_thread(njti.current());
3510 }
3511 }
3512
3513 // All JavaThreads
3514 void Threads::java_threads_do(ThreadClosure* tc) {
3515 assert_locked_or_safepoint(Threads_lock);
3516 // ALL_JAVA_THREADS iterates through all JavaThreads.
3517 ALL_JAVA_THREADS(p) {
3518 tc->do_thread(p);
3519 }
3520 }
3521
3522 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3523 assert_locked_or_safepoint(Threads_lock);
3524 java_threads_do(tc);
3525 tc->do_thread(VMThread::vm_thread());
3526 }
3527
3528 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3529 void Threads::threads_do(ThreadClosure* tc) {
3530 assert_locked_or_safepoint(Threads_lock);
3531 java_threads_do(tc);
3532 non_java_threads_do(tc);
3533 }
3534
3535 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3536 uintx claim_token = Threads::thread_claim_token();
3537 ALL_JAVA_THREADS(p) {
3538 if (p->claim_threads_do(is_par, claim_token)) {
3539 tc->do_thread(p);
3540 }
3541 }
3542 VMThread* vmt = VMThread::vm_thread();
3543 if (vmt->claim_threads_do(is_par, claim_token)) {
3544 tc->do_thread(vmt);
3545 }
3546 }
3547
3548 // The system initialization in the library has three phases.
3549 //
3550 // Phase 1: java.lang.System class initialization
3551 // java.lang.System is a primordial class loaded and initialized
3552 // by the VM early during startup. java.lang.System.<clinit>
3553 // only does registerNatives and keeps the rest of the class
3554 // initialization work later until thread initialization completes.
3555 //
3556 // System.initPhase1 initializes the system properties, the static
3557 // fields in, out, and err. Set up java signal handlers, OS-specific
3558 // system settings, and thread group of the main thread.
3559 static void call_initPhase1(TRAPS) {
3560 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3561 JavaValue result(T_VOID);
3562 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3563 vmSymbols::void_method_signature(), CHECK);
3564 }
3565
3566 // Phase 2. Module system initialization
3567 // This will initialize the module system. Only java.base classes
3568 // can be loaded until phase 2 completes.
3569 //
3570 // Call System.initPhase2 after the compiler initialization and jsr292
3571 // classes get initialized because module initialization runs a lot of java
3572 // code, that for performance reasons, should be compiled. Also, this will
3573 // enable the startup code to use lambda and other language features in this
3574 // phase and onward.
3575 //
3576 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3577 static void call_initPhase2(TRAPS) {
3578 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3579
3580 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3581
3582 JavaValue result(T_INT);
3583 JavaCallArguments args;
3584 args.push_int(DisplayVMOutputToStderr);
3585 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3586 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3587 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3588 if (result.get_jint() != JNI_OK) {
3589 vm_exit_during_initialization(); // no message or exception
3590 }
3591
3592 universe_post_module_init();
3593 }
3594
3595 // Phase 3. final setup - set security manager, system class loader and TCCL
3596 //
3597 // This will instantiate and set the security manager, set the system class
3598 // loader as well as the thread context class loader. The security manager
3599 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3600 // other modules or the application's classpath.
3601 static void call_initPhase3(TRAPS) {
3602 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3603 JavaValue result(T_VOID);
3604 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3605 vmSymbols::void_method_signature(), CHECK);
3606 }
3607
3608 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3609 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3610
3611 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3612 create_vm_init_libraries();
3613 }
3614
3615 initialize_class(vmSymbols::java_lang_String(), CHECK);
3616
3617 // Inject CompactStrings value after the static initializers for String ran.
3618 java_lang_String::set_compact_strings(CompactStrings);
3619
3620 // Initialize java_lang.System (needed before creating the thread)
3621 initialize_class(vmSymbols::java_lang_System(), CHECK);
3622 // The VM creates & returns objects of this class. Make sure it's initialized.
3623 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3624 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3625 Handle thread_group = create_initial_thread_group(CHECK);
3626 Universe::set_main_thread_group(thread_group());
3627 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3628 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3629 main_thread->set_threadObj(thread_object);
3630
3631 // Set thread status to running since main thread has
3632 // been started and running.
3633 java_lang_Thread::set_thread_status(thread_object,
3634 java_lang_Thread::RUNNABLE);
3635
3636 // The VM creates objects of this class.
3637 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3638
3639 #ifdef ASSERT
3640 InstanceKlass *k = SystemDictionary::UnsafeConstants_klass();
3641 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
3642 #endif
3643
3644 // initialize the hardware-specific constants needed by Unsafe
3645 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
3646 jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
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, bool is_daemon) {
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 if (!is_daemon) {
4501 _number_of_non_daemon_threads--;
4502
4503 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4504 // on destroy_vm will wake up.
4505 if (number_of_non_daemon_threads() == 1) {
4506 Threads_lock->notify_all();
4507 }
4508 }
4509 ThreadService::remove_thread(p, is_daemon);
4510
4511 // Make sure that safepoint code disregard this thread. This is needed since
4512 // the thread might mess around with locks after this point. This can cause it
4513 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4514 // of this thread since it is removed from the queue.
4515 p->set_terminated_value();
4516 } // unlock Threads_lock
4517
4518 // Since Events::log uses a lock, we grab it outside the Threads_lock
4519 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4520 }
4521
4522 // Operations on the Threads list for GC. These are not explicitly locked,
4523 // but the garbage collector must provide a safe context for them to run.
4524 // In particular, these things should never be called when the Threads_lock
4525 // is held by some other thread. (Note: the Safepoint abstraction also
4526 // uses the Threads_lock to guarantee this property. It also makes sure that
4527 // all threads gets blocked when exiting or starting).
4528
4529 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4530 ALL_JAVA_THREADS(p) {
4531 p->oops_do(f, cf);
4532 }
4533 VMThread::vm_thread()->oops_do(f, cf);
4534 }
4535
4536 void Threads::change_thread_claim_token() {
4537 if (++_thread_claim_token == 0) {
4538 // On overflow of the token counter, there is a risk of future
4539 // collisions between a new global token value and a stale token
4540 // for a thread, because not all iterations visit all threads.
4541 // (Though it's pretty much a theoretical concern for non-trivial
4542 // token counter sizes.) To deal with the possibility, reset all
4543 // the thread tokens to zero on global token overflow.
4544 struct ResetClaims : public ThreadClosure {
4545 virtual void do_thread(Thread* t) {
4546 t->claim_threads_do(false, 0);
4547 }
4548 } reset_claims;
4549 Threads::threads_do(&reset_claims);
4550 // On overflow, update the global token to non-zero, to
4551 // avoid the special "never claimed" initial thread value.
4552 _thread_claim_token = 1;
4553 }
4554 }
4555
4556 #ifdef ASSERT
4557 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
4558 const uintx token = t->threads_do_token();
4559 assert(token == expected,
4560 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
4561 UINTX_FORMAT, kind, p2i(t), token, expected);
4562 }
4563
4564 void Threads::assert_all_threads_claimed() {
4565 ALL_JAVA_THREADS(p) {
4566 assert_thread_claimed("Thread", p, _thread_claim_token);
4567 }
4568 assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token);
4569 }
4570 #endif // ASSERT
4571
4572 class ParallelOopsDoThreadClosure : public ThreadClosure {
4573 private:
4574 OopClosure* _f;
4575 CodeBlobClosure* _cf;
4576 public:
4577 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4578 void do_thread(Thread* t) {
4579 t->oops_do(_f, _cf);
4580 }
4581 };
4582
4583 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4584 ParallelOopsDoThreadClosure tc(f, cf);
4585 possibly_parallel_threads_do(is_par, &tc);
4586 }
4587
4588 void Threads::nmethods_do(CodeBlobClosure* cf) {
4589 ALL_JAVA_THREADS(p) {
4590 // This is used by the code cache sweeper to mark nmethods that are active
4591 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4592 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4593 if(!p->is_Code_cache_sweeper_thread()) {
4594 p->nmethods_do(cf);
4595 }
4596 }
4597 }
4598
4599 void Threads::metadata_do(MetadataClosure* f) {
4600 ALL_JAVA_THREADS(p) {
4601 p->metadata_do(f);
4602 }
4603 }
4604
4605 class ThreadHandlesClosure : public ThreadClosure {
4606 void (*_f)(Metadata*);
4607 public:
4608 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4609 virtual void do_thread(Thread* thread) {
4610 thread->metadata_handles_do(_f);
4611 }
4612 };
4613
4614 void Threads::metadata_handles_do(void f(Metadata*)) {
4615 // Only walk the Handles in Thread.
4616 ThreadHandlesClosure handles_closure(f);
4617 threads_do(&handles_closure);
4618 }
4619
4620 void Threads::deoptimized_wrt_marked_nmethods() {
4621 ALL_JAVA_THREADS(p) {
4622 p->deoptimized_wrt_marked_nmethods();
4623 }
4624 }
4625
4626
4627 // Get count Java threads that are waiting to enter the specified monitor.
4628 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4629 int count,
4630 address monitor) {
4631 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4632
4633 int i = 0;
4634 DO_JAVA_THREADS(t_list, p) {
4635 if (!p->can_call_java()) continue;
4636
4637 address pending = (address)p->current_pending_monitor();
4638 if (pending == monitor) { // found a match
4639 if (i < count) result->append(p); // save the first count matches
4640 i++;
4641 }
4642 }
4643
4644 return result;
4645 }
4646
4647
4648 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4649 address owner) {
4650 // NULL owner means not locked so we can skip the search
4651 if (owner == NULL) return NULL;
4652
4653 DO_JAVA_THREADS(t_list, p) {
4654 // first, see if owner is the address of a Java thread
4655 if (owner == (address)p) return p;
4656 }
4657
4658 // Cannot assert on lack of success here since this function may be
4659 // used by code that is trying to report useful problem information
4660 // like deadlock detection.
4661 if (UseHeavyMonitors) return NULL;
4662
4663 // If we didn't find a matching Java thread and we didn't force use of
4664 // heavyweight monitors, then the owner is the stack address of the
4665 // Lock Word in the owning Java thread's stack.
4666 //
4667 JavaThread* the_owner = NULL;
4668 DO_JAVA_THREADS(t_list, q) {
4669 if (q->is_lock_owned(owner)) {
4670 the_owner = q;
4671 break;
4672 }
4673 }
4674
4675 // cannot assert on lack of success here; see above comment
4676 return the_owner;
4677 }
4678
4679 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4680 void Threads::print_on(outputStream* st, bool print_stacks,
4681 bool internal_format, bool print_concurrent_locks,
4682 bool print_extended_info) {
4683 char buf[32];
4684 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4685
4686 st->print_cr("Full thread dump %s (%s %s):",
4687 VM_Version::vm_name(),
4688 VM_Version::vm_release(),
4689 VM_Version::vm_info_string());
4690 st->cr();
4691
4692 #if INCLUDE_SERVICES
4693 // Dump concurrent locks
4694 ConcurrentLocksDump concurrent_locks;
4695 if (print_concurrent_locks) {
4696 concurrent_locks.dump_at_safepoint();
4697 }
4698 #endif // INCLUDE_SERVICES
4699
4700 ThreadsSMRSupport::print_info_on(st);
4701 st->cr();
4702
4703 ALL_JAVA_THREADS(p) {
4704 ResourceMark rm;
4705 p->print_on(st, print_extended_info);
4706 if (print_stacks) {
4707 if (internal_format) {
4708 p->trace_stack();
4709 } else {
4710 p->print_stack_on(st);
4711 }
4712 }
4713 st->cr();
4714 #if INCLUDE_SERVICES
4715 if (print_concurrent_locks) {
4716 concurrent_locks.print_locks_on(p, st);
4717 }
4718 #endif // INCLUDE_SERVICES
4719 }
4720
4721 VMThread::vm_thread()->print_on(st);
4722 st->cr();
4723 Universe::heap()->print_gc_threads_on(st);
4724 WatcherThread* wt = WatcherThread::watcher_thread();
4725 if (wt != NULL) {
4726 wt->print_on(st);
4727 st->cr();
4728 }
4729
4730 st->flush();
4731 }
4732
4733 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4734 int buflen, bool* found_current) {
4735 if (this_thread != NULL) {
4736 bool is_current = (current == this_thread);
4737 *found_current = *found_current || is_current;
4738 st->print("%s", is_current ? "=>" : " ");
4739
4740 st->print(PTR_FORMAT, p2i(this_thread));
4741 st->print(" ");
4742 this_thread->print_on_error(st, buf, buflen);
4743 st->cr();
4744 }
4745 }
4746
4747 class PrintOnErrorClosure : public ThreadClosure {
4748 outputStream* _st;
4749 Thread* _current;
4750 char* _buf;
4751 int _buflen;
4752 bool* _found_current;
4753 public:
4754 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4755 int buflen, bool* found_current) :
4756 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4757
4758 virtual void do_thread(Thread* thread) {
4759 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4760 }
4761 };
4762
4763 // Threads::print_on_error() is called by fatal error handler. It's possible
4764 // that VM is not at safepoint and/or current thread is inside signal handler.
4765 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4766 // memory (even in resource area), it might deadlock the error handler.
4767 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4768 int buflen) {
4769 ThreadsSMRSupport::print_info_on(st);
4770 st->cr();
4771
4772 bool found_current = false;
4773 st->print_cr("Java Threads: ( => current thread )");
4774 ALL_JAVA_THREADS(thread) {
4775 print_on_error(thread, st, current, buf, buflen, &found_current);
4776 }
4777 st->cr();
4778
4779 st->print_cr("Other Threads:");
4780 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4781 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4782
4783 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4784 Universe::heap()->gc_threads_do(&print_closure);
4785
4786 if (!found_current) {
4787 st->cr();
4788 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4789 current->print_on_error(st, buf, buflen);
4790 st->cr();
4791 }
4792 st->cr();
4793
4794 st->print_cr("Threads with active compile tasks:");
4795 print_threads_compiling(st, buf, buflen);
4796 }
4797
4798 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
4799 ALL_JAVA_THREADS(thread) {
4800 if (thread->is_Compiler_thread()) {
4801 CompilerThread* ct = (CompilerThread*) thread;
4802
4803 // Keep task in local variable for NULL check.
4804 // ct->_task might be set to NULL by concurring compiler thread
4805 // because it completed the compilation. The task is never freed,
4806 // though, just returned to a free list.
4807 CompileTask* task = ct->task();
4808 if (task != NULL) {
4809 thread->print_name_on_error(st, buf, buflen);
4810 st->print(" ");
4811 task->print(st, NULL, short_form, true);
4812 }
4813 }
4814 }
4815 }
4816
4817
4818 // Internal SpinLock and Mutex
4819 // Based on ParkEvent
4820
4821 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4822 //
4823 // We employ SpinLocks _only for low-contention, fixed-length
4824 // short-duration critical sections where we're concerned
4825 // about native mutex_t or HotSpot Mutex:: latency.
4826 // The mux construct provides a spin-then-block mutual exclusion
4827 // mechanism.
4828 //
4829 // Testing has shown that contention on the ListLock guarding gFreeList
4830 // is common. If we implement ListLock as a simple SpinLock it's common
4831 // for the JVM to devolve to yielding with little progress. This is true
4832 // despite the fact that the critical sections protected by ListLock are
4833 // extremely short.
4834 //
4835 // TODO-FIXME: ListLock should be of type SpinLock.
4836 // We should make this a 1st-class type, integrated into the lock
4837 // hierarchy as leaf-locks. Critically, the SpinLock structure
4838 // should have sufficient padding to avoid false-sharing and excessive
4839 // cache-coherency traffic.
4840
4841
4842 typedef volatile int SpinLockT;
4843
4844 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4845 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4846 return; // normal fast-path return
4847 }
4848
4849 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4850 int ctr = 0;
4851 int Yields = 0;
4852 for (;;) {
4853 while (*adr != 0) {
4854 ++ctr;
4855 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4856 if (Yields > 5) {
4857 os::naked_short_sleep(1);
4858 } else {
4859 os::naked_yield();
4860 ++Yields;
4861 }
4862 } else {
4863 SpinPause();
4864 }
4865 }
4866 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4867 }
4868 }
4869
4870 void Thread::SpinRelease(volatile int * adr) {
4871 assert(*adr != 0, "invariant");
4872 OrderAccess::fence(); // guarantee at least release consistency.
4873 // Roach-motel semantics.
4874 // It's safe if subsequent LDs and STs float "up" into the critical section,
4875 // but prior LDs and STs within the critical section can't be allowed
4876 // to reorder or float past the ST that releases the lock.
4877 // Loads and stores in the critical section - which appear in program
4878 // order before the store that releases the lock - must also appear
4879 // before the store that releases the lock in memory visibility order.
4880 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4881 // the ST of 0 into the lock-word which releases the lock, so fence
4882 // more than covers this on all platforms.
4883 *adr = 0;
4884 }
4885
4886 // muxAcquire and muxRelease:
4887 //
4888 // * muxAcquire and muxRelease support a single-word lock-word construct.
4889 // The LSB of the word is set IFF the lock is held.
4890 // The remainder of the word points to the head of a singly-linked list
4891 // of threads blocked on the lock.
4892 //
4893 // * The current implementation of muxAcquire-muxRelease uses its own
4894 // dedicated Thread._MuxEvent instance. If we're interested in
4895 // minimizing the peak number of extant ParkEvent instances then
4896 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4897 // as certain invariants were satisfied. Specifically, care would need
4898 // to be taken with regards to consuming unpark() "permits".
4899 // A safe rule of thumb is that a thread would never call muxAcquire()
4900 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4901 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4902 // consume an unpark() permit intended for monitorenter, for instance.
4903 // One way around this would be to widen the restricted-range semaphore
4904 // implemented in park(). Another alternative would be to provide
4905 // multiple instances of the PlatformEvent() for each thread. One
4906 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4907 //
4908 // * Usage:
4909 // -- Only as leaf locks
4910 // -- for short-term locking only as muxAcquire does not perform
4911 // thread state transitions.
4912 //
4913 // Alternatives:
4914 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4915 // but with parking or spin-then-park instead of pure spinning.
4916 // * Use Taura-Oyama-Yonenzawa locks.
4917 // * It's possible to construct a 1-0 lock if we encode the lockword as
4918 // (List,LockByte). Acquire will CAS the full lockword while Release
4919 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4920 // acquiring threads use timers (ParkTimed) to detect and recover from
4921 // the stranding window. Thread/Node structures must be aligned on 256-byte
4922 // boundaries by using placement-new.
4923 // * Augment MCS with advisory back-link fields maintained with CAS().
4924 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4925 // The validity of the backlinks must be ratified before we trust the value.
4926 // If the backlinks are invalid the exiting thread must back-track through the
4927 // the forward links, which are always trustworthy.
4928 // * Add a successor indication. The LockWord is currently encoded as
4929 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4930 // to provide the usual futile-wakeup optimization.
4931 // See RTStt for details.
4932 //
4933
4934
4935 const intptr_t LOCKBIT = 1;
4936
4937 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4938 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4939 if (w == 0) return;
4940 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4941 return;
4942 }
4943
4944 ParkEvent * const Self = Thread::current()->_MuxEvent;
4945 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4946 for (;;) {
4947 int its = (os::is_MP() ? 100 : 0) + 1;
4948
4949 // Optional spin phase: spin-then-park strategy
4950 while (--its >= 0) {
4951 w = *Lock;
4952 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4953 return;
4954 }
4955 }
4956
4957 Self->reset();
4958 Self->OnList = intptr_t(Lock);
4959 // The following fence() isn't _strictly necessary as the subsequent
4960 // CAS() both serializes execution and ratifies the fetched *Lock value.
4961 OrderAccess::fence();
4962 for (;;) {
4963 w = *Lock;
4964 if ((w & LOCKBIT) == 0) {
4965 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4966 Self->OnList = 0; // hygiene - allows stronger asserts
4967 return;
4968 }
4969 continue; // Interference -- *Lock changed -- Just retry
4970 }
4971 assert(w & LOCKBIT, "invariant");
4972 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4973 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4974 }
4975
4976 while (Self->OnList != 0) {
4977 Self->park();
4978 }
4979 }
4980 }
4981
4982 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4983 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4984 if (w == 0) return;
4985 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4986 return;
4987 }
4988
4989 ParkEvent * ReleaseAfter = NULL;
4990 if (ev == NULL) {
4991 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4992 }
4993 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4994 for (;;) {
4995 guarantee(ev->OnList == 0, "invariant");
4996 int its = (os::is_MP() ? 100 : 0) + 1;
4997
4998 // Optional spin phase: spin-then-park strategy
4999 while (--its >= 0) {
5000 w = *Lock;
5001 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
5002 if (ReleaseAfter != NULL) {
5003 ParkEvent::Release(ReleaseAfter);
5004 }
5005 return;
5006 }
5007 }
5008
5009 ev->reset();
5010 ev->OnList = intptr_t(Lock);
5011 // The following fence() isn't _strictly necessary as the subsequent
5012 // CAS() both serializes execution and ratifies the fetched *Lock value.
5013 OrderAccess::fence();
5014 for (;;) {
5015 w = *Lock;
5016 if ((w & LOCKBIT) == 0) {
5017 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
5018 ev->OnList = 0;
5019 // We call ::Release while holding the outer lock, thus
5020 // artificially lengthening the critical section.
5021 // Consider deferring the ::Release() until the subsequent unlock(),
5022 // after we've dropped the outer lock.
5023 if (ReleaseAfter != NULL) {
5024 ParkEvent::Release(ReleaseAfter);
5025 }
5026 return;
5027 }
5028 continue; // Interference -- *Lock changed -- Just retry
5029 }
5030 assert(w & LOCKBIT, "invariant");
5031 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
5032 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
5033 }
5034
5035 while (ev->OnList != 0) {
5036 ev->park();
5037 }
5038 }
5039 }
5040
5041 // Release() must extract a successor from the list and then wake that thread.
5042 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
5043 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
5044 // Release() would :
5045 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
5046 // (B) Extract a successor from the private list "in-hand"
5047 // (C) attempt to CAS() the residual back into *Lock over null.
5048 // If there were any newly arrived threads and the CAS() would fail.
5049 // In that case Release() would detach the RATs, re-merge the list in-hand
5050 // with the RATs and repeat as needed. Alternately, Release() might
5051 // detach and extract a successor, but then pass the residual list to the wakee.
5052 // The wakee would be responsible for reattaching and remerging before it
5053 // competed for the lock.
5054 //
5055 // Both "pop" and DMR are immune from ABA corruption -- there can be
5056 // multiple concurrent pushers, but only one popper or detacher.
5057 // This implementation pops from the head of the list. This is unfair,
5058 // but tends to provide excellent throughput as hot threads remain hot.
5059 // (We wake recently run threads first).
5060 //
5061 // All paths through muxRelease() will execute a CAS.
5062 // Release consistency -- We depend on the CAS in muxRelease() to provide full
5063 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
5064 // executed within the critical section are complete and globally visible before the
5065 // store (CAS) to the lock-word that releases the lock becomes globally visible.
5066 void Thread::muxRelease(volatile intptr_t * Lock) {
5067 for (;;) {
5068 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
5069 assert(w & LOCKBIT, "invariant");
5070 if (w == LOCKBIT) return;
5071 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
5072 assert(List != NULL, "invariant");
5073 assert(List->OnList == intptr_t(Lock), "invariant");
5074 ParkEvent * const nxt = List->ListNext;
5075 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5076
5077 // The following CAS() releases the lock and pops the head element.
5078 // The CAS() also ratifies the previously fetched lock-word value.
5079 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
5080 continue;
5081 }
5082 List->OnList = 0;
5083 OrderAccess::fence();
5084 List->unpark();
5085 return;
5086 }
5087 }
5088
5089
5090 void Threads::verify() {
5091 ALL_JAVA_THREADS(p) {
5092 p->verify();
5093 }
5094 VMThread* thread = VMThread::vm_thread();
5095 if (thread != NULL) thread->verify();
5096 }