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