1 /*
2 * Copyright (c) 1997, 2018, 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 "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "jfr/jfrEvents.hpp"
36 #include "jvmtifiles/jvmtiEnv.hpp"
37 #include "memory/gcLocker.inline.hpp"
38 #include "memory/metaspaceShared.hpp"
39 #include "memory/oopFactory.hpp"
40 #include "memory/universe.inline.hpp"
41 #include "oops/instanceKlass.hpp"
42 #include "oops/objArrayOop.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "oops/symbol.hpp"
45 #include "prims/jvm_misc.hpp"
46 #include "prims/jvmtiExport.hpp"
47 #include "prims/jvmtiThreadState.hpp"
48 #include "prims/privilegedStack.hpp"
49 #include "runtime/arguments.hpp"
50 #include "runtime/biasedLocking.hpp"
51 #include "runtime/deoptimization.hpp"
52 #include "runtime/fprofiler.hpp"
53 #include "runtime/frame.inline.hpp"
54 #include "runtime/init.hpp"
55 #include "runtime/interfaceSupport.hpp"
56 #include "runtime/java.hpp"
57 #include "runtime/javaCalls.hpp"
58 #include "runtime/jniPeriodicChecker.hpp"
59 #include "runtime/memprofiler.hpp"
60 #include "runtime/mutexLocker.hpp"
61 #include "runtime/objectMonitor.hpp"
62 #include "runtime/orderAccess.inline.hpp"
63 #include "runtime/osThread.hpp"
64 #include "runtime/safepoint.hpp"
65 #include "runtime/sharedRuntime.hpp"
66 #include "runtime/statSampler.hpp"
67 #include "runtime/stubRoutines.hpp"
68 #include "runtime/task.hpp"
69 #include "runtime/thread.inline.hpp"
70 #include "runtime/threadCritical.hpp"
71 #include "runtime/threadLocalStorage.hpp"
72 #include "runtime/vframe.hpp"
73 #include "runtime/vframeArray.hpp"
74 #include "runtime/vframe_hp.hpp"
75 #include "runtime/vmThread.hpp"
76 #include "runtime/vm_operations.hpp"
77 #include "services/attachListener.hpp"
78 #include "services/management.hpp"
79 #include "services/memTracker.hpp"
80 #include "services/threadService.hpp"
81 #include "utilities/defaultStream.hpp"
82 #include "utilities/dtrace.hpp"
83 #include "utilities/events.hpp"
84 #include "utilities/preserveException.hpp"
85 #include "utilities/macros.hpp"
86 #ifdef TARGET_OS_FAMILY_linux
87 # include "os_linux.inline.hpp"
88 #endif
89 #ifdef TARGET_OS_FAMILY_solaris
90 # include "os_solaris.inline.hpp"
91 #endif
92 #ifdef TARGET_OS_FAMILY_windows
93 # include "os_windows.inline.hpp"
94 #endif
95 #ifdef TARGET_OS_FAMILY_bsd
96 # include "os_bsd.inline.hpp"
97 #endif
98 #if INCLUDE_ALL_GCS
99 #include "gc_implementation/shenandoah/shenandoahControlThread.hpp"
100 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
102 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
103 #endif // INCLUDE_ALL_GCS
104 #ifdef COMPILER1
105 #include "c1/c1_Compiler.hpp"
106 #endif
107 #ifdef COMPILER2
108 #include "opto/c2compiler.hpp"
109 #include "opto/idealGraphPrinter.hpp"
110 #endif
111 #if INCLUDE_RTM_OPT
112 #include "runtime/rtmLocking.hpp"
113 #endif
114 #if INCLUDE_JFR
115 #include "jfr/jfr.hpp"
116 #endif
117
118 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
119
120 #ifdef DTRACE_ENABLED
121
122 // Only bother with this argument setup if dtrace is available
123
124 #ifndef USDT2
125 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
126 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
127 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
128 intptr_t, intptr_t, bool);
129 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
130 intptr_t, intptr_t, bool);
131
132 #define DTRACE_THREAD_PROBE(probe, javathread) \
133 { \
134 ResourceMark rm(this); \
135 int len = 0; \
136 const char* name = (javathread)->get_thread_name(); \
137 len = strlen(name); \
138 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
139 name, len, \
140 java_lang_Thread::thread_id((javathread)->threadObj()), \
141 (javathread)->osthread()->thread_id(), \
142 java_lang_Thread::is_daemon((javathread)->threadObj())); \
143 }
144
145 #else /* USDT2 */
146
147 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
148 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
149
150 #define DTRACE_THREAD_PROBE(probe, javathread) \
151 { \
152 ResourceMark rm(this); \
153 int len = 0; \
154 const char* name = (javathread)->get_thread_name(); \
155 len = strlen(name); \
156 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
157 (char *) name, len, \
158 java_lang_Thread::thread_id((javathread)->threadObj()), \
159 (uintptr_t) (javathread)->osthread()->thread_id(), \
160 java_lang_Thread::is_daemon((javathread)->threadObj())); \
161 }
162
163 #endif /* USDT2 */
164
165 #else // ndef DTRACE_ENABLED
166
167 #define DTRACE_THREAD_PROBE(probe, javathread)
168
169 #endif // ndef DTRACE_ENABLED
170
171
172 // Class hierarchy
173 // - Thread
174 // - VMThread
175 // - WatcherThread
176 // - ConcurrentMarkSweepThread
177 // - JavaThread
178 // - CompilerThread
179
180 // ======= Thread ========
181 // Support for forcing alignment of thread objects for biased locking
182 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
183 if (UseBiasedLocking) {
184 const int alignment = markOopDesc::biased_lock_alignment;
185 size_t aligned_size = size + (alignment - sizeof(intptr_t));
186 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
187 : AllocateHeap(aligned_size, flags, CURRENT_PC,
188 AllocFailStrategy::RETURN_NULL);
189 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
190 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
191 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
192 "JavaThread alignment code overflowed allocated storage");
193 if (TraceBiasedLocking) {
194 if (aligned_addr != real_malloc_addr)
195 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
196 real_malloc_addr, aligned_addr);
197 }
198 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
199 return aligned_addr;
200 } else {
201 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
202 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
203 }
204 }
205
206 void Thread::operator delete(void* p) {
207 if (UseBiasedLocking) {
208 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
209 FreeHeap(real_malloc_addr, mtThread);
210 } else {
211 FreeHeap(p, mtThread);
212 }
213 }
214
215
216 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
217 // JavaThread
218
219
220 Thread::Thread() {
221 // stack and get_thread
222 set_stack_base(NULL);
223 set_stack_size(0);
224 set_self_raw_id(0);
225 set_lgrp_id(-1);
226
227 // allocated data structures
228 set_osthread(NULL);
229 set_resource_area(new (mtThread)ResourceArea());
230 DEBUG_ONLY(_current_resource_mark = NULL;)
231 set_handle_area(new (mtThread) HandleArea(NULL));
232 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
233 set_active_handles(NULL);
234 set_free_handle_block(NULL);
235 set_last_handle_mark(NULL);
236
237 // This initial value ==> never claimed.
238 _oops_do_parity = 0;
239
240 _metadata_on_stack_buffer = NULL;
241
242 // the handle mark links itself to last_handle_mark
243 new HandleMark(this);
244
245 // plain initialization
246 debug_only(_owned_locks = NULL;)
247 debug_only(_allow_allocation_count = 0;)
248 NOT_PRODUCT(_allow_safepoint_count = 0;)
249 NOT_PRODUCT(_skip_gcalot = false;)
250 _jvmti_env_iteration_count = 0;
251 set_allocated_bytes(0);
252 _vm_operation_started_count = 0;
253 _vm_operation_completed_count = 0;
254 _current_pending_monitor = NULL;
255 _current_pending_monitor_is_from_java = true;
256 _current_waiting_monitor = NULL;
257 _num_nested_signal = 0;
258 omFreeList = NULL ;
259 omFreeCount = 0 ;
260 omFreeProvision = 32 ;
261 omInUseList = NULL ;
262 omInUseCount = 0 ;
263
264 #ifdef ASSERT
265 _visited_for_critical_count = false;
266 #endif
267
268 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
269 _suspend_flags = 0;
270
271 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
272 _hashStateX = os::random() ;
273 _hashStateY = 842502087 ;
274 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
275 _hashStateW = 273326509 ;
276
277 _OnTrap = 0 ;
278 _schedctl = NULL ;
279 _Stalled = 0 ;
280 _TypeTag = 0x2BAD ;
281
282 // Many of the following fields are effectively final - immutable
283 // Note that nascent threads can't use the Native Monitor-Mutex
284 // construct until the _MutexEvent is initialized ...
285 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
286 // we might instead use a stack of ParkEvents that we could provision on-demand.
287 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
288 // and ::Release()
289 _ParkEvent = ParkEvent::Allocate (this) ;
290 _SleepEvent = ParkEvent::Allocate (this) ;
291 _MutexEvent = ParkEvent::Allocate (this) ;
292 _MuxEvent = ParkEvent::Allocate (this) ;
293
294 #ifdef CHECK_UNHANDLED_OOPS
295 if (CheckUnhandledOops) {
296 _unhandled_oops = new UnhandledOops(this);
297 }
298 #endif // CHECK_UNHANDLED_OOPS
299 #ifdef ASSERT
300 if (UseBiasedLocking) {
301 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
302 assert(this == _real_malloc_address ||
303 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
304 "bug in forced alignment of thread objects");
305 }
306 #endif /* ASSERT */
307
308 _oom_during_evac = 0;
309 #if INCLUDE_ALL_GCS
310 _gc_state = _gc_state_global;
311 _worker_id = (uint)(-1); // Actually, ShenandoahWorkerSession::INVALID_WORKER_ID, but avoid dependencies.
312 _force_satb_flush = false;
313 _paced_time = 0;
314 #endif
315 }
316
317 void Thread::set_oom_during_evac(bool oom) {
318 if (oom) {
319 _oom_during_evac |= 1;
320 } else {
321 _oom_during_evac &= ~1;
322 }
323 }
324
325 bool Thread::is_oom_during_evac() const {
326 return (_oom_during_evac & 1) == 1;
327 }
328
329 #ifdef ASSERT
330 void Thread::set_evac_allowed(bool evac_allowed) {
331 if (evac_allowed) {
332 _oom_during_evac |= 2;
333 } else {
334 _oom_during_evac &= ~2;
335 }
336 }
337
338 bool Thread::is_evac_allowed() const {
339 return (_oom_during_evac & 2) == 2;
340 }
341 #endif
342
343 void Thread::initialize_thread_local_storage() {
344 // Note: Make sure this method only calls
345 // non-blocking operations. Otherwise, it might not work
346 // with the thread-startup/safepoint interaction.
347
348 // During Java thread startup, safepoint code should allow this
349 // method to complete because it may need to allocate memory to
350 // store information for the new thread.
351
352 // initialize structure dependent on thread local storage
353 ThreadLocalStorage::set_thread(this);
354 }
355
356 void Thread::record_stack_base_and_size() {
357 set_stack_base(os::current_stack_base());
358 set_stack_size(os::current_stack_size());
359 if (is_Java_thread()) {
360 ((JavaThread*) this)->set_stack_overflow_limit();
361 }
362 // CR 7190089: on Solaris, primordial thread's stack is adjusted
363 // in initialize_thread(). Without the adjustment, stack size is
364 // incorrect if stack is set to unlimited (ulimit -s unlimited).
365 // So far, only Solaris has real implementation of initialize_thread().
366 //
367 // set up any platform-specific state.
368 os::initialize_thread(this);
369
370 #if INCLUDE_NMT
371 // record thread's native stack, stack grows downward
372 address stack_low_addr = stack_base() - stack_size();
373 MemTracker::record_thread_stack(stack_low_addr, stack_size());
374 #endif // INCLUDE_NMT
375 }
376
377
378 Thread::~Thread() {
379 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
380 ObjectSynchronizer::omFlush (this) ;
381
382 // stack_base can be NULL if the thread is never started or exited before
383 // record_stack_base_and_size called. Although, we would like to ensure
384 // that all started threads do call record_stack_base_and_size(), there is
385 // not proper way to enforce that.
386 #if INCLUDE_NMT
387 if (_stack_base != NULL) {
388 address low_stack_addr = stack_base() - stack_size();
389 MemTracker::release_thread_stack(low_stack_addr, stack_size());
390 #ifdef ASSERT
391 set_stack_base(NULL);
392 #endif
393 }
394 #endif // INCLUDE_NMT
395
396 // deallocate data structures
397 delete resource_area();
398 // since the handle marks are using the handle area, we have to deallocated the root
399 // handle mark before deallocating the thread's handle area,
400 assert(last_handle_mark() != NULL, "check we have an element");
401 delete last_handle_mark();
402 assert(last_handle_mark() == NULL, "check we have reached the end");
403
404 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
405 // We NULL out the fields for good hygiene.
406 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
407 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
408 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
409 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
410
411 delete handle_area();
412 delete metadata_handles();
413
414 // osthread() can be NULL, if creation of thread failed.
415 if (osthread() != NULL) os::free_thread(osthread());
416
417 delete _SR_lock;
418
419 // clear thread local storage if the Thread is deleting itself
420 if (this == Thread::current()) {
421 ThreadLocalStorage::set_thread(NULL);
422 } else {
423 // In the case where we're not the current thread, invalidate all the
424 // caches in case some code tries to get the current thread or the
425 // thread that was destroyed, and gets stale information.
426 ThreadLocalStorage::invalidate_all();
427 }
428 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
429 }
430
431 // NOTE: dummy function for assertion purpose.
432 void Thread::run() {
433 ShouldNotReachHere();
434 }
435
436 #ifdef ASSERT
437 // Private method to check for dangling thread pointer
438 void check_for_dangling_thread_pointer(Thread *thread) {
439 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
440 "possibility of dangling Thread pointer");
441 }
442 #endif
443
444
445 #ifndef PRODUCT
446 // Tracing method for basic thread operations
447 void Thread::trace(const char* msg, const Thread* const thread) {
448 if (!TraceThreadEvents) return;
449 ResourceMark rm;
450 ThreadCritical tc;
451 const char *name = "non-Java thread";
452 int prio = -1;
453 if (thread->is_Java_thread()
454 && !thread->is_Compiler_thread()) {
455 // The Threads_lock must be held to get information about
456 // this thread but may not be in some situations when
457 // tracing thread events.
458 bool release_Threads_lock = false;
459 if (!Threads_lock->owned_by_self()) {
460 Threads_lock->lock();
461 release_Threads_lock = true;
462 }
463 JavaThread* jt = (JavaThread *)thread;
464 name = (char *)jt->get_thread_name();
465 oop thread_oop = jt->threadObj();
466 if (thread_oop != NULL) {
467 prio = java_lang_Thread::priority(thread_oop);
468 }
469 if (release_Threads_lock) {
470 Threads_lock->unlock();
471 }
472 }
473 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
474 }
475 #endif
476
477
478 ThreadPriority Thread::get_priority(const Thread* const thread) {
479 trace("get priority", thread);
480 ThreadPriority priority;
481 // Can return an error!
482 (void)os::get_priority(thread, priority);
483 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
484 return priority;
485 }
486
487 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
488 trace("set priority", thread);
489 debug_only(check_for_dangling_thread_pointer(thread);)
490 // Can return an error!
491 (void)os::set_priority(thread, priority);
492 }
493
494
495 void Thread::start(Thread* thread) {
496 trace("start", thread);
497 // Start is different from resume in that its safety is guaranteed by context or
498 // being called from a Java method synchronized on the Thread object.
499 if (!DisableStartThread) {
500 if (thread->is_Java_thread()) {
501 // Initialize the thread state to RUNNABLE before starting this thread.
502 // Can not set it after the thread started because we do not know the
503 // exact thread state at that time. It could be in MONITOR_WAIT or
504 // in SLEEPING or some other state.
505 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
506 java_lang_Thread::RUNNABLE);
507 }
508 os::start_thread(thread);
509 }
510 }
511
512 // Enqueue a VM_Operation to do the job for us - sometime later
513 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
514 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
515 VMThread::execute(vm_stop);
516 }
517
518
519 //
520 // Check if an external suspend request has completed (or has been
521 // cancelled). Returns true if the thread is externally suspended and
522 // false otherwise.
523 //
524 // The bits parameter returns information about the code path through
525 // the routine. Useful for debugging:
526 //
527 // set in is_ext_suspend_completed():
528 // 0x00000001 - routine was entered
529 // 0x00000010 - routine return false at end
530 // 0x00000100 - thread exited (return false)
531 // 0x00000200 - suspend request cancelled (return false)
532 // 0x00000400 - thread suspended (return true)
533 // 0x00001000 - thread is in a suspend equivalent state (return true)
534 // 0x00002000 - thread is native and walkable (return true)
535 // 0x00004000 - thread is native_trans and walkable (needed retry)
536 //
537 // set in wait_for_ext_suspend_completion():
538 // 0x00010000 - routine was entered
539 // 0x00020000 - suspend request cancelled before loop (return false)
540 // 0x00040000 - thread suspended before loop (return true)
541 // 0x00080000 - suspend request cancelled in loop (return false)
542 // 0x00100000 - thread suspended in loop (return true)
543 // 0x00200000 - suspend not completed during retry loop (return false)
544 //
545
546 // Helper class for tracing suspend wait debug bits.
547 //
548 // 0x00000100 indicates that the target thread exited before it could
549 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
550 // 0x00080000 each indicate a cancelled suspend request so they don't
551 // count as wait failures either.
552 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
553
554 class TraceSuspendDebugBits : public StackObj {
555 private:
556 JavaThread * jt;
557 bool is_wait;
558 bool called_by_wait; // meaningful when !is_wait
559 uint32_t * bits;
560
561 public:
562 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
563 uint32_t *_bits) {
564 jt = _jt;
565 is_wait = _is_wait;
566 called_by_wait = _called_by_wait;
567 bits = _bits;
568 }
569
570 ~TraceSuspendDebugBits() {
571 if (!is_wait) {
572 #if 1
573 // By default, don't trace bits for is_ext_suspend_completed() calls.
574 // That trace is very chatty.
575 return;
576 #else
577 if (!called_by_wait) {
578 // If tracing for is_ext_suspend_completed() is enabled, then only
579 // trace calls to it from wait_for_ext_suspend_completion()
580 return;
581 }
582 #endif
583 }
584
585 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
586 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
587 MutexLocker ml(Threads_lock); // needed for get_thread_name()
588 ResourceMark rm;
589
590 tty->print_cr(
591 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
592 jt->get_thread_name(), *bits);
593
594 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
595 }
596 }
597 }
598 };
599 #undef DEBUG_FALSE_BITS
600
601
602 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
603 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
604
605 bool did_trans_retry = false; // only do thread_in_native_trans retry once
606 bool do_trans_retry; // flag to force the retry
607
608 *bits |= 0x00000001;
609
610 do {
611 do_trans_retry = false;
612
613 if (is_exiting()) {
614 // Thread is in the process of exiting. This is always checked
615 // first to reduce the risk of dereferencing a freed JavaThread.
616 *bits |= 0x00000100;
617 return false;
618 }
619
620 if (!is_external_suspend()) {
621 // Suspend request is cancelled. This is always checked before
622 // is_ext_suspended() to reduce the risk of a rogue resume
623 // confusing the thread that made the suspend request.
624 *bits |= 0x00000200;
625 return false;
626 }
627
628 if (is_ext_suspended()) {
629 // thread is suspended
630 *bits |= 0x00000400;
631 return true;
632 }
633
634 // Now that we no longer do hard suspends of threads running
635 // native code, the target thread can be changing thread state
636 // while we are in this routine:
637 //
638 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
639 //
640 // We save a copy of the thread state as observed at this moment
641 // and make our decision about suspend completeness based on the
642 // copy. This closes the race where the thread state is seen as
643 // _thread_in_native_trans in the if-thread_blocked check, but is
644 // seen as _thread_blocked in if-thread_in_native_trans check.
645 JavaThreadState save_state = thread_state();
646
647 if (save_state == _thread_blocked && is_suspend_equivalent()) {
648 // If the thread's state is _thread_blocked and this blocking
649 // condition is known to be equivalent to a suspend, then we can
650 // consider the thread to be externally suspended. This means that
651 // the code that sets _thread_blocked has been modified to do
652 // self-suspension if the blocking condition releases. We also
653 // used to check for CONDVAR_WAIT here, but that is now covered by
654 // the _thread_blocked with self-suspension check.
655 //
656 // Return true since we wouldn't be here unless there was still an
657 // external suspend request.
658 *bits |= 0x00001000;
659 return true;
660 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
661 // Threads running native code will self-suspend on native==>VM/Java
662 // transitions. If its stack is walkable (should always be the case
663 // unless this function is called before the actual java_suspend()
664 // call), then the wait is done.
665 *bits |= 0x00002000;
666 return true;
667 } else if (!called_by_wait && !did_trans_retry &&
668 save_state == _thread_in_native_trans &&
669 frame_anchor()->walkable()) {
670 // The thread is transitioning from thread_in_native to another
671 // thread state. check_safepoint_and_suspend_for_native_trans()
672 // will force the thread to self-suspend. If it hasn't gotten
673 // there yet we may have caught the thread in-between the native
674 // code check above and the self-suspend. Lucky us. If we were
675 // called by wait_for_ext_suspend_completion(), then it
676 // will be doing the retries so we don't have to.
677 //
678 // Since we use the saved thread state in the if-statement above,
679 // there is a chance that the thread has already transitioned to
680 // _thread_blocked by the time we get here. In that case, we will
681 // make a single unnecessary pass through the logic below. This
682 // doesn't hurt anything since we still do the trans retry.
683
684 *bits |= 0x00004000;
685
686 // Once the thread leaves thread_in_native_trans for another
687 // thread state, we break out of this retry loop. We shouldn't
688 // need this flag to prevent us from getting back here, but
689 // sometimes paranoia is good.
690 did_trans_retry = true;
691
692 // We wait for the thread to transition to a more usable state.
693 for (int i = 1; i <= SuspendRetryCount; i++) {
694 // We used to do an "os::yield_all(i)" call here with the intention
695 // that yielding would increase on each retry. However, the parameter
696 // is ignored on Linux which means the yield didn't scale up. Waiting
697 // on the SR_lock below provides a much more predictable scale up for
698 // the delay. It also provides a simple/direct point to check for any
699 // safepoint requests from the VMThread
700
701 // temporarily drops SR_lock while doing wait with safepoint check
702 // (if we're a JavaThread - the WatcherThread can also call this)
703 // and increase delay with each retry
704 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
705
706 // check the actual thread state instead of what we saved above
707 if (thread_state() != _thread_in_native_trans) {
708 // the thread has transitioned to another thread state so
709 // try all the checks (except this one) one more time.
710 do_trans_retry = true;
711 break;
712 }
713 } // end retry loop
714
715
716 }
717 } while (do_trans_retry);
718
719 *bits |= 0x00000010;
720 return false;
721 }
722
723 //
724 // Wait for an external suspend request to complete (or be cancelled).
725 // Returns true if the thread is externally suspended and false otherwise.
726 //
727 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
728 uint32_t *bits) {
729 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
730 false /* !called_by_wait */, bits);
731
732 // local flag copies to minimize SR_lock hold time
733 bool is_suspended;
734 bool pending;
735 uint32_t reset_bits;
736
737 // set a marker so is_ext_suspend_completed() knows we are the caller
738 *bits |= 0x00010000;
739
740 // We use reset_bits to reinitialize the bits value at the top of
741 // each retry loop. This allows the caller to make use of any
742 // unused bits for their own marking purposes.
743 reset_bits = *bits;
744
745 {
746 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
747 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
748 delay, bits);
749 pending = is_external_suspend();
750 }
751 // must release SR_lock to allow suspension to complete
752
753 if (!pending) {
754 // A cancelled suspend request is the only false return from
755 // is_ext_suspend_completed() that keeps us from entering the
756 // retry loop.
757 *bits |= 0x00020000;
758 return false;
759 }
760
761 if (is_suspended) {
762 *bits |= 0x00040000;
763 return true;
764 }
765
766 for (int i = 1; i <= retries; i++) {
767 *bits = reset_bits; // reinit to only track last retry
768
769 // We used to do an "os::yield_all(i)" call here with the intention
770 // that yielding would increase on each retry. However, the parameter
771 // is ignored on Linux which means the yield didn't scale up. Waiting
772 // on the SR_lock below provides a much more predictable scale up for
773 // the delay. It also provides a simple/direct point to check for any
774 // safepoint requests from the VMThread
775
776 {
777 MutexLocker ml(SR_lock());
778 // wait with safepoint check (if we're a JavaThread - the WatcherThread
779 // can also call this) and increase delay with each retry
780 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
781
782 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
783 delay, bits);
784
785 // It is possible for the external suspend request to be cancelled
786 // (by a resume) before the actual suspend operation is completed.
787 // Refresh our local copy to see if we still need to wait.
788 pending = is_external_suspend();
789 }
790
791 if (!pending) {
792 // A cancelled suspend request is the only false return from
793 // is_ext_suspend_completed() that keeps us from staying in the
794 // retry loop.
795 *bits |= 0x00080000;
796 return false;
797 }
798
799 if (is_suspended) {
800 *bits |= 0x00100000;
801 return true;
802 }
803 } // end retry loop
804
805 // thread did not suspend after all our retries
806 *bits |= 0x00200000;
807 return false;
808 }
809
810 #ifndef PRODUCT
811 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
812
813 // This should not need to be atomic as the only way for simultaneous
814 // updates is via interrupts. Even then this should be rare or non-existant
815 // and we don't care that much anyway.
816
817 int index = _jmp_ring_index;
818 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
819 _jmp_ring[index]._target = (intptr_t) target;
820 _jmp_ring[index]._instruction = (intptr_t) instr;
821 _jmp_ring[index]._file = file;
822 _jmp_ring[index]._line = line;
823 }
824 #endif /* PRODUCT */
825
826 // Called by flat profiler
827 // Callers have already called wait_for_ext_suspend_completion
828 // The assertion for that is currently too complex to put here:
829 bool JavaThread::profile_last_Java_frame(frame* _fr) {
830 bool gotframe = false;
831 // self suspension saves needed state.
832 if (has_last_Java_frame() && _anchor.walkable()) {
833 *_fr = pd_last_frame();
834 gotframe = true;
835 }
836 return gotframe;
837 }
838
839 void Thread::interrupt(Thread* thread) {
840 trace("interrupt", thread);
841 debug_only(check_for_dangling_thread_pointer(thread);)
842 os::interrupt(thread);
843 }
844
845 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
846 trace("is_interrupted", thread);
847 debug_only(check_for_dangling_thread_pointer(thread);)
848 // Note: If clear_interrupted==false, this simply fetches and
849 // returns the value of the field osthread()->interrupted().
850 return os::is_interrupted(thread, clear_interrupted);
851 }
852
853
854 // GC Support
855 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
856 jint thread_parity = _oops_do_parity;
857 if (thread_parity != strong_roots_parity) {
858 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
859 if (res == thread_parity) {
860 return true;
861 } else {
862 guarantee(res == strong_roots_parity, "Or else what?");
863 assert(SharedHeap::heap()->workers()->active_workers() > 0,
864 "Should only fail when parallel.");
865 return false;
866 }
867 }
868 assert(SharedHeap::heap()->workers()->active_workers() > 0,
869 "Should only fail when parallel.");
870 return false;
871 }
872
873 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
874 if (active_handles() != NULL) {
875 active_handles()->oops_do(f);
876 }
877 // Do oop for ThreadShadow
878 f->do_oop((oop*)&_pending_exception);
879 handle_area()->oops_do(f);
880 }
881
882 void Thread::nmethods_do(CodeBlobClosure* cf) {
883 // no nmethods in a generic thread...
884 }
885
886 void Thread::metadata_do(void f(Metadata*)) {
887 if (metadata_handles() != NULL) {
888 for (int i = 0; i< metadata_handles()->length(); i++) {
889 f(metadata_handles()->at(i));
890 }
891 }
892 }
893
894 void Thread::print_on(outputStream* st) const {
895 // get_priority assumes osthread initialized
896 if (osthread() != NULL) {
897 int os_prio;
898 if (os::get_native_priority(this, &os_prio) == OS_OK) {
899 st->print("os_prio=%d ", os_prio);
900 }
901 st->print("tid=" INTPTR_FORMAT " ", this);
902 ext().print_on(st);
903 osthread()->print_on(st);
904 }
905 debug_only(if (WizardMode) print_owned_locks_on(st);)
906 }
907
908 // Thread::print_on_error() is called by fatal error handler. Don't use
909 // any lock or allocate memory.
910 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
911 if (is_VM_thread()) st->print("VMThread");
912 else if (is_Compiler_thread()) st->print("CompilerThread");
913 else if (is_Java_thread()) st->print("JavaThread");
914 else if (is_GC_task_thread()) st->print("GCTaskThread");
915 else if (is_Watcher_thread()) st->print("WatcherThread");
916 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
917 else st->print("Thread");
918
919 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
920 _stack_base - _stack_size, _stack_base);
921
922 if (osthread()) {
923 st->print(" [id=%d]", osthread()->thread_id());
924 }
925 }
926
927 #ifdef ASSERT
928 void Thread::print_owned_locks_on(outputStream* st) const {
929 Monitor *cur = _owned_locks;
930 if (cur == NULL) {
931 st->print(" (no locks) ");
932 } else {
933 st->print_cr(" Locks owned:");
934 while(cur) {
935 cur->print_on(st);
936 cur = cur->next();
937 }
938 }
939 }
940
941 static int ref_use_count = 0;
942
943 bool Thread::owns_locks_but_compiled_lock() const {
944 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
945 if (cur != Compile_lock) return true;
946 }
947 return false;
948 }
949
950
951 #endif
952
953 #ifndef PRODUCT
954
955 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
956 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
957 // no threads which allow_vm_block's are held
958 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
959 // Check if current thread is allowed to block at a safepoint
960 if (!(_allow_safepoint_count == 0))
961 fatal("Possible safepoint reached by thread that does not allow it");
962 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
963 fatal("LEAF method calling lock?");
964 }
965
966 #ifdef ASSERT
967 if (potential_vm_operation && is_Java_thread()
968 && !Universe::is_bootstrapping()) {
969 // Make sure we do not hold any locks that the VM thread also uses.
970 // This could potentially lead to deadlocks
971 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
972 // Threads_lock is special, since the safepoint synchronization will not start before this is
973 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
974 // since it is used to transfer control between JavaThreads and the VMThread
975 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
976 if ( (cur->allow_vm_block() &&
977 cur != Threads_lock &&
978 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
979 cur != VMOperationRequest_lock &&
980 cur != VMOperationQueue_lock) ||
981 cur->rank() == Mutex::special) {
982 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
983 }
984 }
985 }
986
987 if (GCALotAtAllSafepoints) {
988 // We could enter a safepoint here and thus have a gc
989 InterfaceSupport::check_gc_alot();
990 }
991 #endif
992 }
993 #endif
994
995 bool Thread::is_in_stack(address adr) const {
996 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
997 address end = os::current_stack_pointer();
998 // Allow non Java threads to call this without stack_base
999 if (_stack_base == NULL) return true;
1000 if (stack_base() > adr && adr >= end) return true;
1001
1002 return false;
1003 }
1004
1005
1006 bool Thread::is_in_usable_stack(address adr) const {
1007 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
1008 size_t usable_stack_size = _stack_size - stack_guard_size;
1009
1010 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1011 }
1012
1013
1014 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1015 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1016 // used for compilation in the future. If that change is made, the need for these methods
1017 // should be revisited, and they should be removed if possible.
1018
1019 bool Thread::is_lock_owned(address adr) const {
1020 return on_local_stack(adr);
1021 }
1022
1023 bool Thread::set_as_starting_thread() {
1024 // NOTE: this must be called inside the main thread.
1025 return os::create_main_thread((JavaThread*)this);
1026 }
1027
1028 static void initialize_class(Symbol* class_name, TRAPS) {
1029 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1030 InstanceKlass::cast(klass)->initialize(CHECK);
1031 }
1032
1033
1034 // Creates the initial ThreadGroup
1035 static Handle create_initial_thread_group(TRAPS) {
1036 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1037 instanceKlassHandle klass (THREAD, k);
1038
1039 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1040 {
1041 JavaValue result(T_VOID);
1042 JavaCalls::call_special(&result,
1043 system_instance,
1044 klass,
1045 vmSymbols::object_initializer_name(),
1046 vmSymbols::void_method_signature(),
1047 CHECK_NH);
1048 }
1049 Universe::set_system_thread_group(system_instance());
1050
1051 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1052 {
1053 JavaValue result(T_VOID);
1054 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1055 JavaCalls::call_special(&result,
1056 main_instance,
1057 klass,
1058 vmSymbols::object_initializer_name(),
1059 vmSymbols::threadgroup_string_void_signature(),
1060 system_instance,
1061 string,
1062 CHECK_NH);
1063 }
1064 return main_instance;
1065 }
1066
1067 // Creates the initial Thread
1068 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1069 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1070 instanceKlassHandle klass (THREAD, k);
1071 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1072
1073 java_lang_Thread::set_thread(thread_oop(), thread);
1074 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1075 thread->set_threadObj(thread_oop());
1076
1077 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1078
1079 JavaValue result(T_VOID);
1080 JavaCalls::call_special(&result, thread_oop,
1081 klass,
1082 vmSymbols::object_initializer_name(),
1083 vmSymbols::threadgroup_string_void_signature(),
1084 thread_group,
1085 string,
1086 CHECK_NULL);
1087 return thread_oop();
1088 }
1089
1090 static void call_initializeSystemClass(TRAPS) {
1091 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1092 instanceKlassHandle klass (THREAD, k);
1093
1094 JavaValue result(T_VOID);
1095 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1096 vmSymbols::void_method_signature(), CHECK);
1097 }
1098
1099 char java_runtime_name[128] = "";
1100 char java_runtime_version[128] = "";
1101
1102 // extract the JRE name from sun.misc.Version.java_runtime_name
1103 static const char* get_java_runtime_name(TRAPS) {
1104 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1105 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1106 fieldDescriptor fd;
1107 bool found = k != NULL &&
1108 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1109 vmSymbols::string_signature(), &fd);
1110 if (found) {
1111 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1112 if (name_oop == NULL)
1113 return NULL;
1114 const char* name = java_lang_String::as_utf8_string(name_oop,
1115 java_runtime_name,
1116 sizeof(java_runtime_name));
1117 return name;
1118 } else {
1119 return NULL;
1120 }
1121 }
1122
1123 // extract the JRE version from sun.misc.Version.java_runtime_version
1124 static const char* get_java_runtime_version(TRAPS) {
1125 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1126 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1127 fieldDescriptor fd;
1128 bool found = k != NULL &&
1129 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1130 vmSymbols::string_signature(), &fd);
1131 if (found) {
1132 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1133 if (name_oop == NULL)
1134 return NULL;
1135 const char* name = java_lang_String::as_utf8_string(name_oop,
1136 java_runtime_version,
1137 sizeof(java_runtime_version));
1138 return name;
1139 } else {
1140 return NULL;
1141 }
1142 }
1143
1144 // General purpose hook into Java code, run once when the VM is initialized.
1145 // The Java library method itself may be changed independently from the VM.
1146 static void call_postVMInitHook(TRAPS) {
1147 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1148 instanceKlassHandle klass (THREAD, k);
1149 if (klass.not_null()) {
1150 JavaValue result(T_VOID);
1151 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1152 vmSymbols::void_method_signature(),
1153 CHECK);
1154 }
1155 }
1156
1157 static void reset_vm_info_property(TRAPS) {
1158 // the vm info string
1159 ResourceMark rm(THREAD);
1160 const char *vm_info = VM_Version::vm_info_string();
1161
1162 // java.lang.System class
1163 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1164 instanceKlassHandle klass (THREAD, k);
1165
1166 // setProperty arguments
1167 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1168 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1169
1170 // return value
1171 JavaValue r(T_OBJECT);
1172
1173 // public static String setProperty(String key, String value);
1174 JavaCalls::call_static(&r,
1175 klass,
1176 vmSymbols::setProperty_name(),
1177 vmSymbols::string_string_string_signature(),
1178 key_str,
1179 value_str,
1180 CHECK);
1181 }
1182
1183
1184 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1185 assert(thread_group.not_null(), "thread group should be specified");
1186 assert(threadObj() == NULL, "should only create Java thread object once");
1187
1188 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1189 instanceKlassHandle klass (THREAD, k);
1190 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1191
1192 java_lang_Thread::set_thread(thread_oop(), this);
1193 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1194 set_threadObj(thread_oop());
1195
1196 JavaValue result(T_VOID);
1197 if (thread_name != NULL) {
1198 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1199 // Thread gets assigned specified name and null target
1200 JavaCalls::call_special(&result,
1201 thread_oop,
1202 klass,
1203 vmSymbols::object_initializer_name(),
1204 vmSymbols::threadgroup_string_void_signature(),
1205 thread_group, // Argument 1
1206 name, // Argument 2
1207 THREAD);
1208 } else {
1209 // Thread gets assigned name "Thread-nnn" and null target
1210 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1211 JavaCalls::call_special(&result,
1212 thread_oop,
1213 klass,
1214 vmSymbols::object_initializer_name(),
1215 vmSymbols::threadgroup_runnable_void_signature(),
1216 thread_group, // Argument 1
1217 Handle(), // Argument 2
1218 THREAD);
1219 }
1220
1221
1222 if (daemon) {
1223 java_lang_Thread::set_daemon(thread_oop());
1224 }
1225
1226 if (HAS_PENDING_EXCEPTION) {
1227 return;
1228 }
1229
1230 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1231 Handle threadObj(this, this->threadObj());
1232
1233 JavaCalls::call_special(&result,
1234 thread_group,
1235 group,
1236 vmSymbols::add_method_name(),
1237 vmSymbols::thread_void_signature(),
1238 threadObj, // Arg 1
1239 THREAD);
1240
1241
1242 }
1243
1244 // NamedThread -- non-JavaThread subclasses with multiple
1245 // uniquely named instances should derive from this.
1246 NamedThread::NamedThread() : Thread() {
1247 _name = NULL;
1248 _processed_thread = NULL;
1249 }
1250
1251 NamedThread::~NamedThread() {
1252 JFR_ONLY(Jfr::on_thread_exit(this);)
1253 if (_name != NULL) {
1254 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1255 _name = NULL;
1256 }
1257 }
1258
1259 void NamedThread::set_name(const char* format, ...) {
1260 guarantee(_name == NULL, "Only get to set name once.");
1261 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1262 guarantee(_name != NULL, "alloc failure");
1263 va_list ap;
1264 va_start(ap, format);
1265 jio_vsnprintf(_name, max_name_len, format, ap);
1266 va_end(ap);
1267 }
1268
1269 // ======= WatcherThread ========
1270
1271 // The watcher thread exists to simulate timer interrupts. It should
1272 // be replaced by an abstraction over whatever native support for
1273 // timer interrupts exists on the platform.
1274
1275 WatcherThread* WatcherThread::_watcher_thread = NULL;
1276 bool WatcherThread::_startable = false;
1277 volatile bool WatcherThread::_should_terminate = false;
1278
1279 WatcherThread::WatcherThread() : Thread() {
1280 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1281 if (os::create_thread(this, os::watcher_thread)) {
1282 _watcher_thread = this;
1283
1284 // Set the watcher thread to the highest OS priority which should not be
1285 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1286 // is created. The only normal thread using this priority is the reference
1287 // handler thread, which runs for very short intervals only.
1288 // If the VMThread's priority is not lower than the WatcherThread profiling
1289 // will be inaccurate.
1290 os::set_priority(this, MaxPriority);
1291 if (!DisableStartThread) {
1292 os::start_thread(this);
1293 }
1294 }
1295 }
1296
1297 int WatcherThread::sleep() const {
1298 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1299
1300 // remaining will be zero if there are no tasks,
1301 // causing the WatcherThread to sleep until a task is
1302 // enrolled
1303 int remaining = PeriodicTask::time_to_wait();
1304 int time_slept = 0;
1305
1306 // we expect this to timeout - we only ever get unparked when
1307 // we should terminate or when a new task has been enrolled
1308 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1309
1310 jlong time_before_loop = os::javaTimeNanos();
1311
1312 for (;;) {
1313 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1314 jlong now = os::javaTimeNanos();
1315
1316 if (remaining == 0) {
1317 // if we didn't have any tasks we could have waited for a long time
1318 // consider the time_slept zero and reset time_before_loop
1319 time_slept = 0;
1320 time_before_loop = now;
1321 } else {
1322 // need to recalulate since we might have new tasks in _tasks
1323 time_slept = (int) ((now - time_before_loop) / 1000000);
1324 }
1325
1326 // Change to task list or spurious wakeup of some kind
1327 if (timedout || _should_terminate) {
1328 break;
1329 }
1330
1331 remaining = PeriodicTask::time_to_wait();
1332 if (remaining == 0) {
1333 // Last task was just disenrolled so loop around and wait until
1334 // another task gets enrolled
1335 continue;
1336 }
1337
1338 remaining -= time_slept;
1339 if (remaining <= 0)
1340 break;
1341 }
1342
1343 return time_slept;
1344 }
1345
1346 void WatcherThread::run() {
1347 assert(this == watcher_thread(), "just checking");
1348
1349 this->record_stack_base_and_size();
1350 this->initialize_thread_local_storage();
1351 this->set_native_thread_name(this->name());
1352 this->set_active_handles(JNIHandleBlock::allocate_block());
1353 while(!_should_terminate) {
1354 assert(watcher_thread() == Thread::current(), "thread consistency check");
1355 assert(watcher_thread() == this, "thread consistency check");
1356
1357 // Calculate how long it'll be until the next PeriodicTask work
1358 // should be done, and sleep that amount of time.
1359 int time_waited = sleep();
1360
1361 if (is_error_reported()) {
1362 // A fatal error has happened, the error handler(VMError::report_and_die)
1363 // should abort JVM after creating an error log file. However in some
1364 // rare cases, the error handler itself might deadlock. Here we try to
1365 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1366 //
1367 // This code is in WatcherThread because WatcherThread wakes up
1368 // periodically so the fatal error handler doesn't need to do anything;
1369 // also because the WatcherThread is less likely to crash than other
1370 // threads.
1371
1372 for (;;) {
1373 if (!ShowMessageBoxOnError
1374 && (OnError == NULL || OnError[0] == '\0')
1375 && Arguments::abort_hook() == NULL) {
1376 os::sleep(this, 2 * 60 * 1000, false);
1377 fdStream err(defaultStream::output_fd());
1378 err.print_raw_cr("# [ timer expired, abort... ]");
1379 // skip atexit/vm_exit/vm_abort hooks
1380 os::die();
1381 }
1382
1383 // Wake up 5 seconds later, the fatal handler may reset OnError or
1384 // ShowMessageBoxOnError when it is ready to abort.
1385 os::sleep(this, 5 * 1000, false);
1386 }
1387 }
1388
1389 PeriodicTask::real_time_tick(time_waited);
1390 }
1391
1392 // Signal that it is terminated
1393 {
1394 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1395 _watcher_thread = NULL;
1396 Terminator_lock->notify();
1397 }
1398
1399 // Thread destructor usually does this..
1400 ThreadLocalStorage::set_thread(NULL);
1401 }
1402
1403 void WatcherThread::start() {
1404 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1405
1406 if (watcher_thread() == NULL && _startable) {
1407 _should_terminate = false;
1408 // Create the single instance of WatcherThread
1409 new WatcherThread();
1410 }
1411 }
1412
1413 void WatcherThread::make_startable() {
1414 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1415 _startable = true;
1416 }
1417
1418 void WatcherThread::stop() {
1419 {
1420 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1421 _should_terminate = true;
1422 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1423
1424 WatcherThread* watcher = watcher_thread();
1425 if (watcher != NULL)
1426 watcher->unpark();
1427 }
1428
1429 // it is ok to take late safepoints here, if needed
1430 MutexLocker mu(Terminator_lock);
1431
1432 while(watcher_thread() != NULL) {
1433 // This wait should make safepoint checks, wait without a timeout,
1434 // and wait as a suspend-equivalent condition.
1435 //
1436 // Note: If the FlatProfiler is running, then this thread is waiting
1437 // for the WatcherThread to terminate and the WatcherThread, via the
1438 // FlatProfiler task, is waiting for the external suspend request on
1439 // this thread to complete. wait_for_ext_suspend_completion() will
1440 // eventually timeout, but that takes time. Making this wait a
1441 // suspend-equivalent condition solves that timeout problem.
1442 //
1443 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1444 Mutex::_as_suspend_equivalent_flag);
1445 }
1446 }
1447
1448 void WatcherThread::unpark() {
1449 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1450 PeriodicTask_lock->notify();
1451 }
1452
1453 void WatcherThread::print_on(outputStream* st) const {
1454 st->print("\"%s\" ", name());
1455 Thread::print_on(st);
1456 st->cr();
1457 }
1458
1459 // ======= JavaThread ========
1460
1461 // A JavaThread is a normal Java thread
1462
1463 void JavaThread::initialize() {
1464 // Initialize fields
1465
1466 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1467 set_claimed_par_id(UINT_MAX);
1468
1469 set_saved_exception_pc(NULL);
1470 set_threadObj(NULL);
1471 _anchor.clear();
1472 set_entry_point(NULL);
1473 set_jni_functions(jni_functions());
1474 set_callee_target(NULL);
1475 set_vm_result(NULL);
1476 set_vm_result_2(NULL);
1477 set_vframe_array_head(NULL);
1478 set_vframe_array_last(NULL);
1479 set_deferred_locals(NULL);
1480 set_deopt_mark(NULL);
1481 set_deopt_nmethod(NULL);
1482 clear_must_deopt_id();
1483 set_monitor_chunks(NULL);
1484 set_next(NULL);
1485 set_thread_state(_thread_new);
1486 _terminated = _not_terminated;
1487 _privileged_stack_top = NULL;
1488 _array_for_gc = NULL;
1489 _suspend_equivalent = false;
1490 _in_deopt_handler = 0;
1491 _doing_unsafe_access = false;
1492 _stack_guard_state = stack_guard_unused;
1493 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1494 _exception_pc = 0;
1495 _exception_handler_pc = 0;
1496 _is_method_handle_return = 0;
1497 _jvmti_thread_state= NULL;
1498 _should_post_on_exceptions_flag = JNI_FALSE;
1499 _jvmti_get_loaded_classes_closure = NULL;
1500 _interp_only_mode = 0;
1501 _special_runtime_exit_condition = _no_async_condition;
1502 _pending_async_exception = NULL;
1503 _thread_stat = NULL;
1504 _thread_stat = new ThreadStatistics();
1505 _blocked_on_compilation = false;
1506 _jni_active_critical = 0;
1507 _pending_jni_exception_check_fn = NULL;
1508 _do_not_unlock_if_synchronized = false;
1509 _cached_monitor_info = NULL;
1510 _parker = Parker::Allocate(this) ;
1511
1512 #ifndef PRODUCT
1513 _jmp_ring_index = 0;
1514 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1515 record_jump(NULL, NULL, NULL, 0);
1516 }
1517 #endif /* PRODUCT */
1518
1519 set_thread_profiler(NULL);
1520 if (FlatProfiler::is_active()) {
1521 // This is where we would decide to either give each thread it's own profiler
1522 // or use one global one from FlatProfiler,
1523 // or up to some count of the number of profiled threads, etc.
1524 ThreadProfiler* pp = new ThreadProfiler();
1525 pp->engage();
1526 set_thread_profiler(pp);
1527 }
1528
1529 // Setup safepoint state info for this thread
1530 ThreadSafepointState::create(this);
1531
1532 debug_only(_java_call_counter = 0);
1533
1534 // JVMTI PopFrame support
1535 _popframe_condition = popframe_inactive;
1536 _popframe_preserved_args = NULL;
1537 _popframe_preserved_args_size = 0;
1538 _frames_to_pop_failed_realloc = 0;
1539
1540 pd_initialize();
1541 }
1542
1543 #if INCLUDE_ALL_GCS
1544 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1545 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1546 char Thread::_gc_state_global = 0;
1547 #endif // INCLUDE_ALL_GCS
1548
1549 JavaThread::JavaThread(bool is_attaching_via_jni) :
1550 Thread()
1551 #if INCLUDE_ALL_GCS
1552 , _satb_mark_queue(&_satb_mark_queue_set),
1553 _dirty_card_queue(&_dirty_card_queue_set)
1554 #endif // INCLUDE_ALL_GCS
1555 {
1556 initialize();
1557 if (is_attaching_via_jni) {
1558 _jni_attach_state = _attaching_via_jni;
1559 } else {
1560 _jni_attach_state = _not_attaching_via_jni;
1561 }
1562 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1563 }
1564
1565 bool JavaThread::reguard_stack(address cur_sp) {
1566 if (_stack_guard_state != stack_guard_yellow_disabled) {
1567 return true; // Stack already guarded or guard pages not needed.
1568 }
1569
1570 if (register_stack_overflow()) {
1571 // For those architectures which have separate register and
1572 // memory stacks, we must check the register stack to see if
1573 // it has overflowed.
1574 return false;
1575 }
1576
1577 // Java code never executes within the yellow zone: the latter is only
1578 // there to provoke an exception during stack banging. If java code
1579 // is executing there, either StackShadowPages should be larger, or
1580 // some exception code in c1, c2 or the interpreter isn't unwinding
1581 // when it should.
1582 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1583
1584 enable_stack_yellow_zone();
1585 return true;
1586 }
1587
1588 bool JavaThread::reguard_stack(void) {
1589 return reguard_stack(os::current_stack_pointer());
1590 }
1591
1592
1593 void JavaThread::block_if_vm_exited() {
1594 if (_terminated == _vm_exited) {
1595 // _vm_exited is set at safepoint, and Threads_lock is never released
1596 // we will block here forever
1597 Threads_lock->lock_without_safepoint_check();
1598 ShouldNotReachHere();
1599 }
1600 }
1601
1602
1603 // Remove this ifdef when C1 is ported to the compiler interface.
1604 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1605
1606 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1607 Thread()
1608 #if INCLUDE_ALL_GCS
1609 , _satb_mark_queue(&_satb_mark_queue_set),
1610 _dirty_card_queue(&_dirty_card_queue_set)
1611 #endif // INCLUDE_ALL_GCS
1612 {
1613 if (TraceThreadEvents) {
1614 tty->print_cr("creating thread %p", this);
1615 }
1616 initialize();
1617 _jni_attach_state = _not_attaching_via_jni;
1618 set_entry_point(entry_point);
1619 // Create the native thread itself.
1620 // %note runtime_23
1621 os::ThreadType thr_type = os::java_thread;
1622 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1623 os::java_thread;
1624 os::create_thread(this, thr_type, stack_sz);
1625 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1626 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1627 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1628 // the exception consists of creating the exception object & initializing it, initialization
1629 // will leave the VM via a JavaCall and then all locks must be unlocked).
1630 //
1631 // The thread is still suspended when we reach here. Thread must be explicit started
1632 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1633 // by calling Threads:add. The reason why this is not done here, is because the thread
1634 // object must be fully initialized (take a look at JVM_Start)
1635 }
1636
1637 JavaThread::~JavaThread() {
1638 if (TraceThreadEvents) {
1639 tty->print_cr("terminate thread %p", this);
1640 }
1641
1642 // JSR166 -- return the parker to the free list
1643 Parker::Release(_parker);
1644 _parker = NULL ;
1645
1646 // Free any remaining previous UnrollBlock
1647 vframeArray* old_array = vframe_array_last();
1648
1649 if (old_array != NULL) {
1650 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1651 old_array->set_unroll_block(NULL);
1652 delete old_info;
1653 delete old_array;
1654 }
1655
1656 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1657 if (deferred != NULL) {
1658 // This can only happen if thread is destroyed before deoptimization occurs.
1659 assert(deferred->length() != 0, "empty array!");
1660 do {
1661 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1662 deferred->remove_at(0);
1663 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1664 delete dlv;
1665 } while (deferred->length() != 0);
1666 delete deferred;
1667 }
1668
1669 // All Java related clean up happens in exit
1670 ThreadSafepointState::destroy(this);
1671 if (_thread_profiler != NULL) delete _thread_profiler;
1672 if (_thread_stat != NULL) delete _thread_stat;
1673 }
1674
1675
1676 // The first routine called by a new Java thread
1677 void JavaThread::run() {
1678 // initialize thread-local alloc buffer related fields
1679 this->initialize_tlab();
1680
1681 // used to test validitity of stack trace backs
1682 this->record_base_of_stack_pointer();
1683
1684 // Record real stack base and size.
1685 this->record_stack_base_and_size();
1686
1687 // Initialize thread local storage; set before calling MutexLocker
1688 this->initialize_thread_local_storage();
1689
1690 this->create_stack_guard_pages();
1691
1692 this->cache_global_variables();
1693
1694 // Thread is now sufficient initialized to be handled by the safepoint code as being
1695 // in the VM. Change thread state from _thread_new to _thread_in_vm
1696 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1697
1698 assert(JavaThread::current() == this, "sanity check");
1699 assert(!Thread::current()->owns_locks(), "sanity check");
1700
1701 DTRACE_THREAD_PROBE(start, this);
1702
1703 // This operation might block. We call that after all safepoint checks for a new thread has
1704 // been completed.
1705 this->set_active_handles(JNIHandleBlock::allocate_block());
1706
1707 if (JvmtiExport::should_post_thread_life()) {
1708 JvmtiExport::post_thread_start(this);
1709 }
1710
1711 JFR_ONLY(Jfr::on_thread_start(this);)
1712
1713 // We call another function to do the rest so we are sure that the stack addresses used
1714 // from there will be lower than the stack base just computed
1715 thread_main_inner();
1716
1717 // Note, thread is no longer valid at this point!
1718 }
1719
1720
1721 void JavaThread::thread_main_inner() {
1722 assert(JavaThread::current() == this, "sanity check");
1723 assert(this->threadObj() != NULL, "just checking");
1724
1725 // Execute thread entry point unless this thread has a pending exception
1726 // or has been stopped before starting.
1727 // Note: Due to JVM_StopThread we can have pending exceptions already!
1728 if (!this->has_pending_exception() &&
1729 !java_lang_Thread::is_stillborn(this->threadObj())) {
1730 {
1731 ResourceMark rm(this);
1732 this->set_native_thread_name(this->get_thread_name());
1733 }
1734 HandleMark hm(this);
1735 this->entry_point()(this, this);
1736 }
1737
1738 DTRACE_THREAD_PROBE(stop, this);
1739
1740 this->exit(false);
1741 delete this;
1742 }
1743
1744
1745 static void ensure_join(JavaThread* thread) {
1746 // We do not need to grap the Threads_lock, since we are operating on ourself.
1747 Handle threadObj(thread, thread->threadObj());
1748 assert(threadObj.not_null(), "java thread object must exist");
1749 ObjectLocker lock(threadObj, thread);
1750 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1751 thread->clear_pending_exception();
1752 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1753 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1754 // Clear the native thread instance - this makes isAlive return false and allows the join()
1755 // to complete once we've done the notify_all below
1756 java_lang_Thread::set_thread(threadObj(), NULL);
1757 lock.notify_all(thread);
1758 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1759 thread->clear_pending_exception();
1760 }
1761
1762
1763 // For any new cleanup additions, please check to see if they need to be applied to
1764 // cleanup_failed_attach_current_thread as well.
1765 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1766 assert(this == JavaThread::current(), "thread consistency check");
1767
1768 HandleMark hm(this);
1769 Handle uncaught_exception(this, this->pending_exception());
1770 this->clear_pending_exception();
1771 Handle threadObj(this, this->threadObj());
1772 assert(threadObj.not_null(), "Java thread object should be created");
1773
1774 if (get_thread_profiler() != NULL) {
1775 get_thread_profiler()->disengage();
1776 ResourceMark rm;
1777 get_thread_profiler()->print(get_thread_name());
1778 }
1779
1780
1781 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1782 {
1783 EXCEPTION_MARK;
1784
1785 CLEAR_PENDING_EXCEPTION;
1786 }
1787 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1788 // has to be fixed by a runtime query method
1789 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1790 // JSR-166: change call from from ThreadGroup.uncaughtException to
1791 // java.lang.Thread.dispatchUncaughtException
1792 if (uncaught_exception.not_null()) {
1793 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1794 {
1795 EXCEPTION_MARK;
1796 // Check if the method Thread.dispatchUncaughtException() exists. If so
1797 // call it. Otherwise we have an older library without the JSR-166 changes,
1798 // so call ThreadGroup.uncaughtException()
1799 KlassHandle recvrKlass(THREAD, threadObj->klass());
1800 CallInfo callinfo;
1801 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1802 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1803 vmSymbols::dispatchUncaughtException_name(),
1804 vmSymbols::throwable_void_signature(),
1805 KlassHandle(), false, false, THREAD);
1806 CLEAR_PENDING_EXCEPTION;
1807 methodHandle method = callinfo.selected_method();
1808 if (method.not_null()) {
1809 JavaValue result(T_VOID);
1810 JavaCalls::call_virtual(&result,
1811 threadObj, thread_klass,
1812 vmSymbols::dispatchUncaughtException_name(),
1813 vmSymbols::throwable_void_signature(),
1814 uncaught_exception,
1815 THREAD);
1816 } else {
1817 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1818 JavaValue result(T_VOID);
1819 JavaCalls::call_virtual(&result,
1820 group, thread_group,
1821 vmSymbols::uncaughtException_name(),
1822 vmSymbols::thread_throwable_void_signature(),
1823 threadObj, // Arg 1
1824 uncaught_exception, // Arg 2
1825 THREAD);
1826 }
1827 if (HAS_PENDING_EXCEPTION) {
1828 ResourceMark rm(this);
1829 jio_fprintf(defaultStream::error_stream(),
1830 "\nException: %s thrown from the UncaughtExceptionHandler"
1831 " in thread \"%s\"\n",
1832 pending_exception()->klass()->external_name(),
1833 get_thread_name());
1834 CLEAR_PENDING_EXCEPTION;
1835 }
1836 }
1837 }
1838 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
1839
1840 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1841 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1842 // is deprecated anyhow.
1843 if (!is_Compiler_thread()) {
1844 int count = 3;
1845 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1846 EXCEPTION_MARK;
1847 JavaValue result(T_VOID);
1848 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1849 JavaCalls::call_virtual(&result,
1850 threadObj, thread_klass,
1851 vmSymbols::exit_method_name(),
1852 vmSymbols::void_method_signature(),
1853 THREAD);
1854 CLEAR_PENDING_EXCEPTION;
1855 }
1856 }
1857 // notify JVMTI
1858 if (JvmtiExport::should_post_thread_life()) {
1859 JvmtiExport::post_thread_end(this);
1860 }
1861
1862 // We have notified the agents that we are exiting, before we go on,
1863 // we must check for a pending external suspend request and honor it
1864 // in order to not surprise the thread that made the suspend request.
1865 while (true) {
1866 {
1867 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1868 if (!is_external_suspend()) {
1869 set_terminated(_thread_exiting);
1870 ThreadService::current_thread_exiting(this);
1871 break;
1872 }
1873 // Implied else:
1874 // Things get a little tricky here. We have a pending external
1875 // suspend request, but we are holding the SR_lock so we
1876 // can't just self-suspend. So we temporarily drop the lock
1877 // and then self-suspend.
1878 }
1879
1880 ThreadBlockInVM tbivm(this);
1881 java_suspend_self();
1882
1883 // We're done with this suspend request, but we have to loop around
1884 // and check again. Eventually we will get SR_lock without a pending
1885 // external suspend request and will be able to mark ourselves as
1886 // exiting.
1887 }
1888 // no more external suspends are allowed at this point
1889 } else {
1890 // before_exit() has already posted JVMTI THREAD_END events
1891 }
1892
1893 // Notify waiters on thread object. This has to be done after exit() is called
1894 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1895 // group should have the destroyed bit set before waiters are notified).
1896 ensure_join(this);
1897 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1898
1899 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1900 // held by this thread must be released. A detach operation must only
1901 // get here if there are no Java frames on the stack. Therefore, any
1902 // owned monitors at this point MUST be JNI-acquired monitors which are
1903 // pre-inflated and in the monitor cache.
1904 //
1905 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1906 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1907 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1908 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1909 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1910 }
1911
1912 // These things needs to be done while we are still a Java Thread. Make sure that thread
1913 // is in a consistent state, in case GC happens
1914 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1915 JFR_ONLY(Jfr::on_thread_exit(this);)
1916
1917 if (active_handles() != NULL) {
1918 JNIHandleBlock* block = active_handles();
1919 set_active_handles(NULL);
1920 JNIHandleBlock::release_block(block);
1921 }
1922
1923 if (free_handle_block() != NULL) {
1924 JNIHandleBlock* block = free_handle_block();
1925 set_free_handle_block(NULL);
1926 JNIHandleBlock::release_block(block);
1927 }
1928
1929 // These have to be removed while this is still a valid thread.
1930 remove_stack_guard_pages();
1931
1932 if (UseTLAB) {
1933 tlab().make_parsable(true); // retire TLAB
1934 }
1935
1936 if (JvmtiEnv::environments_might_exist()) {
1937 JvmtiExport::cleanup_thread(this);
1938 }
1939
1940 // We must flush any deferred card marks before removing a thread from
1941 // the list of active threads.
1942 Universe::heap()->flush_deferred_store_barrier(this);
1943 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1944
1945 #if INCLUDE_ALL_GCS
1946 // We must flush the G1-related buffers before removing a thread
1947 // from the list of active threads. We must do this after any deferred
1948 // card marks have been flushed (above) so that any entries that are
1949 // added to the thread's dirty card queue as a result are not lost.
1950 if (UseG1GC || (UseShenandoahGC)) {
1951 flush_barrier_queues();
1952 }
1953 if (UseShenandoahGC && UseTLAB && gclab().is_initialized()) {
1954 gclab().make_parsable(true);
1955 }
1956 #endif // INCLUDE_ALL_GCS
1957
1958 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1959 Threads::remove(this);
1960 }
1961
1962 #if INCLUDE_ALL_GCS
1963 // Flush G1-related queues.
1964 void JavaThread::flush_barrier_queues() {
1965 satb_mark_queue().flush();
1966 dirty_card_queue().flush();
1967 }
1968
1969 void JavaThread::initialize_queues() {
1970 assert(!SafepointSynchronize::is_at_safepoint(),
1971 "we should not be at a safepoint");
1972
1973 ObjPtrQueue& satb_queue = satb_mark_queue();
1974 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1975 // The SATB queue should have been constructed with its active
1976 // field set to false.
1977 assert(!satb_queue.is_active(), "SATB queue should not be active");
1978 assert(satb_queue.is_empty(), "SATB queue should be empty");
1979 // If we are creating the thread during a marking cycle, we should
1980 // set the active field of the SATB queue to true.
1981 if (satb_queue_set.is_active()) {
1982 satb_queue.set_active(true);
1983 }
1984
1985 DirtyCardQueue& dirty_queue = dirty_card_queue();
1986 // The dirty card queue should have been constructed with its
1987 // active field set to true.
1988 assert(dirty_queue.is_active(), "dirty card queue should be active");
1989
1990 _gc_state = _gc_state_global;
1991 }
1992
1993 void JavaThread::set_gc_state(char in_prog) {
1994 _gc_state = in_prog;
1995 }
1996
1997 void JavaThread::set_gc_state_all_threads(char in_prog) {
1998 assert_locked_or_safepoint(Threads_lock);
1999 _gc_state_global = in_prog;
2000 for (JavaThread* t = Threads::first(); t != NULL; t = t->next()) {
2001 t->set_gc_state(in_prog);
2002 }
2003 }
2004
2005 void JavaThread::set_force_satb_flush_all_threads(bool value) {
2006 assert_locked_or_safepoint(Threads_lock);
2007 for (JavaThread* t = Threads::first(); t != NULL; t = t->next()) {
2008 t->set_force_satb_flush(value);
2009 }
2010 }
2011 #endif // INCLUDE_ALL_GCS
2012
2013 void JavaThread::cleanup_failed_attach_current_thread() {
2014 if (get_thread_profiler() != NULL) {
2015 get_thread_profiler()->disengage();
2016 ResourceMark rm;
2017 get_thread_profiler()->print(get_thread_name());
2018 }
2019
2020 if (active_handles() != NULL) {
2021 JNIHandleBlock* block = active_handles();
2022 set_active_handles(NULL);
2023 JNIHandleBlock::release_block(block);
2024 }
2025
2026 if (free_handle_block() != NULL) {
2027 JNIHandleBlock* block = free_handle_block();
2028 set_free_handle_block(NULL);
2029 JNIHandleBlock::release_block(block);
2030 }
2031
2032 // These have to be removed while this is still a valid thread.
2033 remove_stack_guard_pages();
2034
2035 if (UseTLAB) {
2036 tlab().make_parsable(true); // retire TLAB, if any
2037 }
2038
2039 #if INCLUDE_ALL_GCS
2040 if (UseG1GC || (UseShenandoahGC)) {
2041 flush_barrier_queues();
2042 }
2043 if (UseShenandoahGC && UseTLAB && gclab().is_initialized()) {
2044 gclab().make_parsable(true);
2045 }
2046 #endif // INCLUDE_ALL_GCS
2047
2048 Threads::remove(this);
2049 delete this;
2050 }
2051
2052
2053
2054
2055 JavaThread* JavaThread::active() {
2056 Thread* thread = ThreadLocalStorage::thread();
2057 assert(thread != NULL, "just checking");
2058 if (thread->is_Java_thread()) {
2059 return (JavaThread*) thread;
2060 } else {
2061 assert(thread->is_VM_thread(), "this must be a vm thread");
2062 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2063 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2064 assert(ret->is_Java_thread(), "must be a Java thread");
2065 return ret;
2066 }
2067 }
2068
2069 bool JavaThread::is_lock_owned(address adr) const {
2070 if (Thread::is_lock_owned(adr)) return true;
2071
2072 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2073 if (chunk->contains(adr)) return true;
2074 }
2075
2076 return false;
2077 }
2078
2079
2080 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2081 chunk->set_next(monitor_chunks());
2082 set_monitor_chunks(chunk);
2083 }
2084
2085 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2086 guarantee(monitor_chunks() != NULL, "must be non empty");
2087 if (monitor_chunks() == chunk) {
2088 set_monitor_chunks(chunk->next());
2089 } else {
2090 MonitorChunk* prev = monitor_chunks();
2091 while (prev->next() != chunk) prev = prev->next();
2092 prev->set_next(chunk->next());
2093 }
2094 }
2095
2096 // JVM support.
2097
2098 // Note: this function shouldn't block if it's called in
2099 // _thread_in_native_trans state (such as from
2100 // check_special_condition_for_native_trans()).
2101 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2102
2103 if (has_last_Java_frame() && has_async_condition()) {
2104 // If we are at a polling page safepoint (not a poll return)
2105 // then we must defer async exception because live registers
2106 // will be clobbered by the exception path. Poll return is
2107 // ok because the call we a returning from already collides
2108 // with exception handling registers and so there is no issue.
2109 // (The exception handling path kills call result registers but
2110 // this is ok since the exception kills the result anyway).
2111
2112 if (is_at_poll_safepoint()) {
2113 // if the code we are returning to has deoptimized we must defer
2114 // the exception otherwise live registers get clobbered on the
2115 // exception path before deoptimization is able to retrieve them.
2116 //
2117 RegisterMap map(this, false);
2118 frame caller_fr = last_frame().sender(&map);
2119 assert(caller_fr.is_compiled_frame(), "what?");
2120 if (caller_fr.is_deoptimized_frame()) {
2121 if (TraceExceptions) {
2122 ResourceMark rm;
2123 tty->print_cr("deferred async exception at compiled safepoint");
2124 }
2125 return;
2126 }
2127 }
2128 }
2129
2130 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2131 if (condition == _no_async_condition) {
2132 // Conditions have changed since has_special_runtime_exit_condition()
2133 // was called:
2134 // - if we were here only because of an external suspend request,
2135 // then that was taken care of above (or cancelled) so we are done
2136 // - if we were here because of another async request, then it has
2137 // been cleared between the has_special_runtime_exit_condition()
2138 // and now so again we are done
2139 return;
2140 }
2141
2142 // Check for pending async. exception
2143 if (_pending_async_exception != NULL) {
2144 // Only overwrite an already pending exception, if it is not a threadDeath.
2145 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2146
2147 // We cannot call Exceptions::_throw(...) here because we cannot block
2148 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2149
2150 if (TraceExceptions) {
2151 ResourceMark rm;
2152 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2153 if (has_last_Java_frame() ) {
2154 frame f = last_frame();
2155 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2156 }
2157 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2158 }
2159 _pending_async_exception = NULL;
2160 clear_has_async_exception();
2161 }
2162 }
2163
2164 if (check_unsafe_error &&
2165 condition == _async_unsafe_access_error && !has_pending_exception()) {
2166 condition = _no_async_condition; // done
2167 switch (thread_state()) {
2168 case _thread_in_vm:
2169 {
2170 JavaThread* THREAD = this;
2171 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2172 }
2173 case _thread_in_native:
2174 {
2175 ThreadInVMfromNative tiv(this);
2176 JavaThread* THREAD = this;
2177 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2178 }
2179 case _thread_in_Java:
2180 {
2181 ThreadInVMfromJava tiv(this);
2182 JavaThread* THREAD = this;
2183 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2184 }
2185 default:
2186 ShouldNotReachHere();
2187 }
2188 }
2189
2190 assert(condition == _no_async_condition || has_pending_exception() ||
2191 (!check_unsafe_error && condition == _async_unsafe_access_error),
2192 "must have handled the async condition, if no exception");
2193 }
2194
2195 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2196 //
2197 // Check for pending external suspend. Internal suspend requests do
2198 // not use handle_special_runtime_exit_condition().
2199 // If JNIEnv proxies are allowed, don't self-suspend if the target
2200 // thread is not the current thread. In older versions of jdbx, jdbx
2201 // threads could call into the VM with another thread's JNIEnv so we
2202 // can be here operating on behalf of a suspended thread (4432884).
2203 bool do_self_suspend = is_external_suspend_with_lock();
2204 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2205 //
2206 // Because thread is external suspended the safepoint code will count
2207 // thread as at a safepoint. This can be odd because we can be here
2208 // as _thread_in_Java which would normally transition to _thread_blocked
2209 // at a safepoint. We would like to mark the thread as _thread_blocked
2210 // before calling java_suspend_self like all other callers of it but
2211 // we must then observe proper safepoint protocol. (We can't leave
2212 // _thread_blocked with a safepoint in progress). However we can be
2213 // here as _thread_in_native_trans so we can't use a normal transition
2214 // constructor/destructor pair because they assert on that type of
2215 // transition. We could do something like:
2216 //
2217 // JavaThreadState state = thread_state();
2218 // set_thread_state(_thread_in_vm);
2219 // {
2220 // ThreadBlockInVM tbivm(this);
2221 // java_suspend_self()
2222 // }
2223 // set_thread_state(_thread_in_vm_trans);
2224 // if (safepoint) block;
2225 // set_thread_state(state);
2226 //
2227 // but that is pretty messy. Instead we just go with the way the
2228 // code has worked before and note that this is the only path to
2229 // java_suspend_self that doesn't put the thread in _thread_blocked
2230 // mode.
2231
2232 frame_anchor()->make_walkable(this);
2233 java_suspend_self();
2234
2235 // We might be here for reasons in addition to the self-suspend request
2236 // so check for other async requests.
2237 }
2238
2239 if (check_asyncs) {
2240 check_and_handle_async_exceptions();
2241 }
2242
2243 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2244 }
2245
2246 void JavaThread::send_thread_stop(oop java_throwable) {
2247 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2248 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2249 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2250
2251 // Do not throw asynchronous exceptions against the compiler thread
2252 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2253 if (is_Compiler_thread()) return;
2254
2255 {
2256 // Actually throw the Throwable against the target Thread - however
2257 // only if there is no thread death exception installed already.
2258 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2259 // If the topmost frame is a runtime stub, then we are calling into
2260 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2261 // must deoptimize the caller before continuing, as the compiled exception handler table
2262 // may not be valid
2263 if (has_last_Java_frame()) {
2264 frame f = last_frame();
2265 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2266 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2267 RegisterMap reg_map(this, UseBiasedLocking);
2268 frame compiled_frame = f.sender(®_map);
2269 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2270 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2271 }
2272 }
2273 }
2274
2275 // Set async. pending exception in thread.
2276 set_pending_async_exception(java_throwable);
2277
2278 if (TraceExceptions) {
2279 ResourceMark rm;
2280 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2281 }
2282 // for AbortVMOnException flag
2283 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2284 }
2285 }
2286
2287
2288 // Interrupt thread so it will wake up from a potential wait()
2289 Thread::interrupt(this);
2290 }
2291
2292 // External suspension mechanism.
2293 //
2294 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2295 // to any VM_locks and it is at a transition
2296 // Self-suspension will happen on the transition out of the vm.
2297 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2298 //
2299 // Guarantees on return:
2300 // + Target thread will not execute any new bytecode (that's why we need to
2301 // force a safepoint)
2302 // + Target thread will not enter any new monitors
2303 //
2304 void JavaThread::java_suspend() {
2305 { MutexLocker mu(Threads_lock);
2306 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2307 return;
2308 }
2309 }
2310
2311 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2312 if (!is_external_suspend()) {
2313 // a racing resume has cancelled us; bail out now
2314 return;
2315 }
2316
2317 // suspend is done
2318 uint32_t debug_bits = 0;
2319 // Warning: is_ext_suspend_completed() may temporarily drop the
2320 // SR_lock to allow the thread to reach a stable thread state if
2321 // it is currently in a transient thread state.
2322 if (is_ext_suspend_completed(false /* !called_by_wait */,
2323 SuspendRetryDelay, &debug_bits) ) {
2324 return;
2325 }
2326 }
2327
2328 VM_ForceSafepoint vm_suspend;
2329 VMThread::execute(&vm_suspend);
2330 }
2331
2332 // Part II of external suspension.
2333 // A JavaThread self suspends when it detects a pending external suspend
2334 // request. This is usually on transitions. It is also done in places
2335 // where continuing to the next transition would surprise the caller,
2336 // e.g., monitor entry.
2337 //
2338 // Returns the number of times that the thread self-suspended.
2339 //
2340 // Note: DO NOT call java_suspend_self() when you just want to block current
2341 // thread. java_suspend_self() is the second stage of cooperative
2342 // suspension for external suspend requests and should only be used
2343 // to complete an external suspend request.
2344 //
2345 int JavaThread::java_suspend_self() {
2346 int ret = 0;
2347
2348 // we are in the process of exiting so don't suspend
2349 if (is_exiting()) {
2350 clear_external_suspend();
2351 return ret;
2352 }
2353
2354 assert(_anchor.walkable() ||
2355 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2356 "must have walkable stack");
2357
2358 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2359
2360 assert(!this->is_ext_suspended(),
2361 "a thread trying to self-suspend should not already be suspended");
2362
2363 if (this->is_suspend_equivalent()) {
2364 // If we are self-suspending as a result of the lifting of a
2365 // suspend equivalent condition, then the suspend_equivalent
2366 // flag is not cleared until we set the ext_suspended flag so
2367 // that wait_for_ext_suspend_completion() returns consistent
2368 // results.
2369 this->clear_suspend_equivalent();
2370 }
2371
2372 // A racing resume may have cancelled us before we grabbed SR_lock
2373 // above. Or another external suspend request could be waiting for us
2374 // by the time we return from SR_lock()->wait(). The thread
2375 // that requested the suspension may already be trying to walk our
2376 // stack and if we return now, we can change the stack out from under
2377 // it. This would be a "bad thing (TM)" and cause the stack walker
2378 // to crash. We stay self-suspended until there are no more pending
2379 // external suspend requests.
2380 while (is_external_suspend()) {
2381 ret++;
2382 this->set_ext_suspended();
2383
2384 // _ext_suspended flag is cleared by java_resume()
2385 while (is_ext_suspended()) {
2386 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2387 }
2388 }
2389
2390 return ret;
2391 }
2392
2393 #ifdef ASSERT
2394 // verify the JavaThread has not yet been published in the Threads::list, and
2395 // hence doesn't need protection from concurrent access at this stage
2396 void JavaThread::verify_not_published() {
2397 if (!Threads_lock->owned_by_self()) {
2398 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2399 assert( !Threads::includes(this),
2400 "java thread shouldn't have been published yet!");
2401 }
2402 else {
2403 assert( !Threads::includes(this),
2404 "java thread shouldn't have been published yet!");
2405 }
2406 }
2407 #endif
2408
2409 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2410 // progress or when _suspend_flags is non-zero.
2411 // Current thread needs to self-suspend if there is a suspend request and/or
2412 // block if a safepoint is in progress.
2413 // Async exception ISN'T checked.
2414 // Note only the ThreadInVMfromNative transition can call this function
2415 // directly and when thread state is _thread_in_native_trans
2416 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2417 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2418
2419 JavaThread *curJT = JavaThread::current();
2420 bool do_self_suspend = thread->is_external_suspend();
2421
2422 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2423
2424 // If JNIEnv proxies are allowed, don't self-suspend if the target
2425 // thread is not the current thread. In older versions of jdbx, jdbx
2426 // threads could call into the VM with another thread's JNIEnv so we
2427 // can be here operating on behalf of a suspended thread (4432884).
2428 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2429 JavaThreadState state = thread->thread_state();
2430
2431 // We mark this thread_blocked state as a suspend-equivalent so
2432 // that a caller to is_ext_suspend_completed() won't be confused.
2433 // The suspend-equivalent state is cleared by java_suspend_self().
2434 thread->set_suspend_equivalent();
2435
2436 // If the safepoint code sees the _thread_in_native_trans state, it will
2437 // wait until the thread changes to other thread state. There is no
2438 // guarantee on how soon we can obtain the SR_lock and complete the
2439 // self-suspend request. It would be a bad idea to let safepoint wait for
2440 // too long. Temporarily change the state to _thread_blocked to
2441 // let the VM thread know that this thread is ready for GC. The problem
2442 // of changing thread state is that safepoint could happen just after
2443 // java_suspend_self() returns after being resumed, and VM thread will
2444 // see the _thread_blocked state. We must check for safepoint
2445 // after restoring the state and make sure we won't leave while a safepoint
2446 // is in progress.
2447 thread->set_thread_state(_thread_blocked);
2448 thread->java_suspend_self();
2449 thread->set_thread_state(state);
2450 // Make sure new state is seen by VM thread
2451 if (os::is_MP()) {
2452 if (UseMembar) {
2453 // Force a fence between the write above and read below
2454 OrderAccess::fence();
2455 } else {
2456 // Must use this rather than serialization page in particular on Windows
2457 InterfaceSupport::serialize_memory(thread);
2458 }
2459 }
2460 }
2461
2462 if (SafepointSynchronize::do_call_back()) {
2463 // If we are safepointing, then block the caller which may not be
2464 // the same as the target thread (see above).
2465 SafepointSynchronize::block(curJT);
2466 }
2467
2468 if (thread->is_deopt_suspend()) {
2469 thread->clear_deopt_suspend();
2470 RegisterMap map(thread, false);
2471 frame f = thread->last_frame();
2472 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2473 f = f.sender(&map);
2474 }
2475 if (f.id() == thread->must_deopt_id()) {
2476 thread->clear_must_deopt_id();
2477 f.deoptimize(thread);
2478 } else {
2479 fatal("missed deoptimization!");
2480 }
2481 }
2482
2483 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2484 }
2485
2486 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2487 // progress or when _suspend_flags is non-zero.
2488 // Current thread needs to self-suspend if there is a suspend request and/or
2489 // block if a safepoint is in progress.
2490 // Also check for pending async exception (not including unsafe access error).
2491 // Note only the native==>VM/Java barriers can call this function and when
2492 // thread state is _thread_in_native_trans.
2493 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2494 check_safepoint_and_suspend_for_native_trans(thread);
2495
2496 if (thread->has_async_exception()) {
2497 // We are in _thread_in_native_trans state, don't handle unsafe
2498 // access error since that may block.
2499 thread->check_and_handle_async_exceptions(false);
2500 }
2501 }
2502
2503 // This is a variant of the normal
2504 // check_special_condition_for_native_trans with slightly different
2505 // semantics for use by critical native wrappers. It does all the
2506 // normal checks but also performs the transition back into
2507 // thread_in_Java state. This is required so that critical natives
2508 // can potentially block and perform a GC if they are the last thread
2509 // exiting the GC_locker.
2510 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2511 check_special_condition_for_native_trans(thread);
2512
2513 // Finish the transition
2514 thread->set_thread_state(_thread_in_Java);
2515
2516 if (thread->do_critical_native_unlock()) {
2517 ThreadInVMfromJavaNoAsyncException tiv(thread);
2518 GC_locker::unlock_critical(thread);
2519 thread->clear_critical_native_unlock();
2520 }
2521 }
2522
2523 // We need to guarantee the Threads_lock here, since resumes are not
2524 // allowed during safepoint synchronization
2525 // Can only resume from an external suspension
2526 void JavaThread::java_resume() {
2527 assert_locked_or_safepoint(Threads_lock);
2528
2529 // Sanity check: thread is gone, has started exiting or the thread
2530 // was not externally suspended.
2531 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2532 return;
2533 }
2534
2535 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2536
2537 clear_external_suspend();
2538
2539 if (is_ext_suspended()) {
2540 clear_ext_suspended();
2541 SR_lock()->notify_all();
2542 }
2543 }
2544
2545 void JavaThread::create_stack_guard_pages() {
2546 if (!os::uses_stack_guard_pages() ||
2547 _stack_guard_state != stack_guard_unused ||
2548 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2549 if (TraceThreadEvents) {
2550 tty->print_cr("Stack guard page creation for thread "
2551 UINTX_FORMAT " disabled", os::current_thread_id());
2552 }
2553 return;
2554 }
2555 address low_addr = stack_base() - stack_size();
2556 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2557
2558 int allocate = os::allocate_stack_guard_pages();
2559 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2560
2561 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2562 warning("Attempt to allocate stack guard pages failed.");
2563 return;
2564 }
2565
2566 if (os::guard_memory((char *) low_addr, len)) {
2567 _stack_guard_state = stack_guard_enabled;
2568 } else {
2569 warning("Attempt to protect stack guard pages failed.");
2570 if (os::uncommit_memory((char *) low_addr, len)) {
2571 warning("Attempt to deallocate stack guard pages failed.");
2572 }
2573 }
2574 }
2575
2576 void JavaThread::remove_stack_guard_pages() {
2577 assert(Thread::current() == this, "from different thread");
2578 if (_stack_guard_state == stack_guard_unused) return;
2579 address low_addr = stack_base() - stack_size();
2580 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2581
2582 if (os::allocate_stack_guard_pages()) {
2583 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2584 _stack_guard_state = stack_guard_unused;
2585 } else {
2586 warning("Attempt to deallocate stack guard pages failed.");
2587 }
2588 } else {
2589 if (_stack_guard_state == stack_guard_unused) return;
2590 if (os::unguard_memory((char *) low_addr, len)) {
2591 _stack_guard_state = stack_guard_unused;
2592 } else {
2593 warning("Attempt to unprotect stack guard pages failed.");
2594 }
2595 }
2596 }
2597
2598 void JavaThread::enable_stack_yellow_zone() {
2599 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2600 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2601
2602 // The base notation is from the stacks point of view, growing downward.
2603 // We need to adjust it to work correctly with guard_memory()
2604 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2605
2606 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2607 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2608
2609 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2610 _stack_guard_state = stack_guard_enabled;
2611 } else {
2612 warning("Attempt to guard stack yellow zone failed.");
2613 }
2614 enable_register_stack_guard();
2615 }
2616
2617 void JavaThread::disable_stack_yellow_zone() {
2618 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2619 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2620
2621 // Simply return if called for a thread that does not use guard pages.
2622 if (_stack_guard_state == stack_guard_unused) return;
2623
2624 // The base notation is from the stacks point of view, growing downward.
2625 // We need to adjust it to work correctly with guard_memory()
2626 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2627
2628 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2629 _stack_guard_state = stack_guard_yellow_disabled;
2630 } else {
2631 warning("Attempt to unguard stack yellow zone failed.");
2632 }
2633 disable_register_stack_guard();
2634 }
2635
2636 void JavaThread::enable_stack_red_zone() {
2637 // The base notation is from the stacks point of view, growing downward.
2638 // We need to adjust it to work correctly with guard_memory()
2639 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2640 address base = stack_red_zone_base() - stack_red_zone_size();
2641
2642 guarantee(base < stack_base(),"Error calculating stack red zone");
2643 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2644
2645 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2646 warning("Attempt to guard stack red zone failed.");
2647 }
2648 }
2649
2650 void JavaThread::disable_stack_red_zone() {
2651 // The base notation is from the stacks point of view, growing downward.
2652 // We need to adjust it to work correctly with guard_memory()
2653 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2654 address base = stack_red_zone_base() - stack_red_zone_size();
2655 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2656 warning("Attempt to unguard stack red zone failed.");
2657 }
2658 }
2659
2660 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2661 // ignore is there is no stack
2662 if (!has_last_Java_frame()) return;
2663 // traverse the stack frames. Starts from top frame.
2664 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2665 frame* fr = fst.current();
2666 f(fr, fst.register_map());
2667 }
2668 }
2669
2670
2671 #ifndef PRODUCT
2672 // Deoptimization
2673 // Function for testing deoptimization
2674 void JavaThread::deoptimize() {
2675 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2676 StackFrameStream fst(this, UseBiasedLocking);
2677 bool deopt = false; // Dump stack only if a deopt actually happens.
2678 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2679 // Iterate over all frames in the thread and deoptimize
2680 for(; !fst.is_done(); fst.next()) {
2681 if(fst.current()->can_be_deoptimized()) {
2682
2683 if (only_at) {
2684 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2685 // consists of comma or carriage return separated numbers so
2686 // search for the current bci in that string.
2687 address pc = fst.current()->pc();
2688 nmethod* nm = (nmethod*) fst.current()->cb();
2689 ScopeDesc* sd = nm->scope_desc_at( pc);
2690 char buffer[8];
2691 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2692 size_t len = strlen(buffer);
2693 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2694 while (found != NULL) {
2695 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2696 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2697 // Check that the bci found is bracketed by terminators.
2698 break;
2699 }
2700 found = strstr(found + 1, buffer);
2701 }
2702 if (!found) {
2703 continue;
2704 }
2705 }
2706
2707 if (DebugDeoptimization && !deopt) {
2708 deopt = true; // One-time only print before deopt
2709 tty->print_cr("[BEFORE Deoptimization]");
2710 trace_frames();
2711 trace_stack();
2712 }
2713 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2714 }
2715 }
2716
2717 if (DebugDeoptimization && deopt) {
2718 tty->print_cr("[AFTER Deoptimization]");
2719 trace_frames();
2720 }
2721 }
2722
2723
2724 // Make zombies
2725 void JavaThread::make_zombies() {
2726 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2727 if (fst.current()->can_be_deoptimized()) {
2728 // it is a Java nmethod
2729 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2730 nm->make_not_entrant();
2731 }
2732 }
2733 }
2734 #endif // PRODUCT
2735
2736
2737 void JavaThread::deoptimized_wrt_marked_nmethods() {
2738 if (!has_last_Java_frame()) return;
2739 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2740 StackFrameStream fst(this, UseBiasedLocking);
2741 for(; !fst.is_done(); fst.next()) {
2742 if (fst.current()->should_be_deoptimized()) {
2743 if (LogCompilation && xtty != NULL) {
2744 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2745 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2746 this->name(), nm != NULL ? nm->compile_id() : -1);
2747 }
2748
2749 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2750 }
2751 }
2752 }
2753
2754
2755 // GC support
2756 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2757
2758 void JavaThread::gc_epilogue() {
2759 frames_do(frame_gc_epilogue);
2760 }
2761
2762
2763 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2764
2765 void JavaThread::gc_prologue() {
2766 frames_do(frame_gc_prologue);
2767 }
2768
2769 // If the caller is a NamedThread, then remember, in the current scope,
2770 // the given JavaThread in its _processed_thread field.
2771 class RememberProcessedThread: public StackObj {
2772 NamedThread* _cur_thr;
2773 public:
2774 RememberProcessedThread(JavaThread* jthr) {
2775 Thread* thread = Thread::current();
2776 if (thread->is_Named_thread()) {
2777 _cur_thr = (NamedThread *)thread;
2778 _cur_thr->set_processed_thread(jthr);
2779 } else {
2780 _cur_thr = NULL;
2781 }
2782 }
2783
2784 ~RememberProcessedThread() {
2785 if (_cur_thr) {
2786 _cur_thr->set_processed_thread(NULL);
2787 }
2788 }
2789 };
2790
2791 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2792 // Verify that the deferred card marks have been flushed.
2793 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2794
2795 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2796 // since there may be more than one thread using each ThreadProfiler.
2797
2798 // Traverse the GCHandles
2799 Thread::oops_do(f, cld_f, cf);
2800
2801 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2802 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2803
2804 if (has_last_Java_frame()) {
2805 // Record JavaThread to GC thread
2806 RememberProcessedThread rpt(this);
2807
2808 // Traverse the privileged stack
2809 if (_privileged_stack_top != NULL) {
2810 _privileged_stack_top->oops_do(f);
2811 }
2812
2813 // traverse the registered growable array
2814 if (_array_for_gc != NULL) {
2815 for (int index = 0; index < _array_for_gc->length(); index++) {
2816 f->do_oop(_array_for_gc->adr_at(index));
2817 }
2818 }
2819
2820 // Traverse the monitor chunks
2821 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2822 chunk->oops_do(f);
2823 }
2824
2825 // Traverse the execution stack
2826 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2827 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2828 }
2829 }
2830
2831 // callee_target is never live across a gc point so NULL it here should
2832 // it still contain a methdOop.
2833
2834 set_callee_target(NULL);
2835
2836 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2837 // If we have deferred set_locals there might be oops waiting to be
2838 // written
2839 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2840 if (list != NULL) {
2841 for (int i = 0; i < list->length(); i++) {
2842 list->at(i)->oops_do(f);
2843 }
2844 }
2845
2846 // Traverse instance variables at the end since the GC may be moving things
2847 // around using this function
2848 f->do_oop((oop*) &_threadObj);
2849 f->do_oop((oop*) &_vm_result);
2850 f->do_oop((oop*) &_exception_oop);
2851 f->do_oop((oop*) &_pending_async_exception);
2852
2853 if (jvmti_thread_state() != NULL) {
2854 jvmti_thread_state()->oops_do(f);
2855 }
2856 }
2857
2858 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2859 Thread::nmethods_do(cf); // (super method is a no-op)
2860
2861 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2862 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2863
2864 if (has_last_Java_frame()) {
2865 // Traverse the execution stack
2866 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2867 fst.current()->nmethods_do(cf);
2868 }
2869 }
2870 }
2871
2872 void JavaThread::metadata_do(void f(Metadata*)) {
2873 Thread::metadata_do(f);
2874 if (has_last_Java_frame()) {
2875 // Traverse the execution stack to call f() on the methods in the stack
2876 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2877 fst.current()->metadata_do(f);
2878 }
2879 } else if (is_Compiler_thread()) {
2880 // need to walk ciMetadata in current compile tasks to keep alive.
2881 CompilerThread* ct = (CompilerThread*)this;
2882 if (ct->env() != NULL) {
2883 ct->env()->metadata_do(f);
2884 }
2885 }
2886 }
2887
2888 // Printing
2889 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2890 switch (_thread_state) {
2891 case _thread_uninitialized: return "_thread_uninitialized";
2892 case _thread_new: return "_thread_new";
2893 case _thread_new_trans: return "_thread_new_trans";
2894 case _thread_in_native: return "_thread_in_native";
2895 case _thread_in_native_trans: return "_thread_in_native_trans";
2896 case _thread_in_vm: return "_thread_in_vm";
2897 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2898 case _thread_in_Java: return "_thread_in_Java";
2899 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2900 case _thread_blocked: return "_thread_blocked";
2901 case _thread_blocked_trans: return "_thread_blocked_trans";
2902 default: return "unknown thread state";
2903 }
2904 }
2905
2906 #ifndef PRODUCT
2907 void JavaThread::print_thread_state_on(outputStream *st) const {
2908 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2909 };
2910 void JavaThread::print_thread_state() const {
2911 print_thread_state_on(tty);
2912 };
2913 #endif // PRODUCT
2914
2915 // Called by Threads::print() for VM_PrintThreads operation
2916 void JavaThread::print_on(outputStream *st) const {
2917 st->print("\"%s\" ", get_thread_name());
2918 oop thread_oop = threadObj();
2919 if (thread_oop != NULL) {
2920 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2921 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2922 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2923 }
2924 Thread::print_on(st);
2925 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2926 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2927 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2928 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2929 }
2930 #ifndef PRODUCT
2931 print_thread_state_on(st);
2932 _safepoint_state->print_on(st);
2933 #endif // PRODUCT
2934 }
2935
2936 // Called by fatal error handler. The difference between this and
2937 // JavaThread::print() is that we can't grab lock or allocate memory.
2938 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2939 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2940 oop thread_obj = threadObj();
2941 if (thread_obj != NULL) {
2942 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2943 }
2944 st->print(" [");
2945 st->print("%s", _get_thread_state_name(_thread_state));
2946 if (osthread()) {
2947 st->print(", id=%d", osthread()->thread_id());
2948 }
2949 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2950 _stack_base - _stack_size, _stack_base);
2951 st->print("]");
2952 return;
2953 }
2954
2955 // Verification
2956
2957 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2958
2959 void JavaThread::verify() {
2960 // Verify oops in the thread.
2961 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2962
2963 // Verify the stack frames.
2964 frames_do(frame_verify);
2965 }
2966
2967 // CR 6300358 (sub-CR 2137150)
2968 // Most callers of this method assume that it can't return NULL but a
2969 // thread may not have a name whilst it is in the process of attaching to
2970 // the VM - see CR 6412693, and there are places where a JavaThread can be
2971 // seen prior to having it's threadObj set (eg JNI attaching threads and
2972 // if vm exit occurs during initialization). These cases can all be accounted
2973 // for such that this method never returns NULL.
2974 const char* JavaThread::get_thread_name() const {
2975 #ifdef ASSERT
2976 // early safepoints can hit while current thread does not yet have TLS
2977 if (!SafepointSynchronize::is_at_safepoint()) {
2978 Thread *cur = Thread::current();
2979 if (!(cur->is_Java_thread() && cur == this)) {
2980 // Current JavaThreads are allowed to get their own name without
2981 // the Threads_lock.
2982 assert_locked_or_safepoint(Threads_lock);
2983 }
2984 }
2985 #endif // ASSERT
2986 return get_thread_name_string();
2987 }
2988
2989 // Returns a non-NULL representation of this thread's name, or a suitable
2990 // descriptive string if there is no set name
2991 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2992 const char* name_str;
2993 oop thread_obj = threadObj();
2994 if (thread_obj != NULL) {
2995 oop name = java_lang_Thread::name(thread_obj);
2996 if (name != NULL) {
2997 if (buf == NULL) {
2998 name_str = java_lang_String::as_utf8_string(name);
2999 }
3000 else {
3001 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3002 }
3003 }
3004 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3005 name_str = "<no-name - thread is attaching>";
3006 }
3007 else {
3008 name_str = Thread::name();
3009 }
3010 }
3011 else {
3012 name_str = Thread::name();
3013 }
3014 assert(name_str != NULL, "unexpected NULL thread name");
3015 return name_str;
3016 }
3017
3018
3019 const char* JavaThread::get_threadgroup_name() const {
3020 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3021 oop thread_obj = threadObj();
3022 if (thread_obj != NULL) {
3023 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3024 if (thread_group != NULL) {
3025 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
3026 // ThreadGroup.name can be null
3027 if (name != NULL) {
3028 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
3029 return str;
3030 }
3031 }
3032 }
3033 return NULL;
3034 }
3035
3036 const char* JavaThread::get_parent_name() const {
3037 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3038 oop thread_obj = threadObj();
3039 if (thread_obj != NULL) {
3040 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3041 if (thread_group != NULL) {
3042 oop parent = java_lang_ThreadGroup::parent(thread_group);
3043 if (parent != NULL) {
3044 typeArrayOop name = java_lang_ThreadGroup::name(parent);
3045 // ThreadGroup.name can be null
3046 if (name != NULL) {
3047 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
3048 return str;
3049 }
3050 }
3051 }
3052 }
3053 return NULL;
3054 }
3055
3056 ThreadPriority JavaThread::java_priority() const {
3057 oop thr_oop = threadObj();
3058 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3059 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3060 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3061 return priority;
3062 }
3063
3064 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3065
3066 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3067 // Link Java Thread object <-> C++ Thread
3068
3069 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3070 // and put it into a new Handle. The Handle "thread_oop" can then
3071 // be used to pass the C++ thread object to other methods.
3072
3073 // Set the Java level thread object (jthread) field of the
3074 // new thread (a JavaThread *) to C++ thread object using the
3075 // "thread_oop" handle.
3076
3077 // Set the thread field (a JavaThread *) of the
3078 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3079
3080 Handle thread_oop(Thread::current(),
3081 JNIHandles::resolve_non_null(jni_thread));
3082 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3083 "must be initialized");
3084 set_threadObj(thread_oop());
3085 java_lang_Thread::set_thread(thread_oop(), this);
3086
3087 if (prio == NoPriority) {
3088 prio = java_lang_Thread::priority(thread_oop());
3089 assert(prio != NoPriority, "A valid priority should be present");
3090 }
3091
3092 // Push the Java priority down to the native thread; needs Threads_lock
3093 Thread::set_priority(this, prio);
3094
3095 prepare_ext();
3096
3097 // Add the new thread to the Threads list and set it in motion.
3098 // We must have threads lock in order to call Threads::add.
3099 // It is crucial that we do not block before the thread is
3100 // added to the Threads list for if a GC happens, then the java_thread oop
3101 // will not be visited by GC.
3102 Threads::add(this);
3103 }
3104
3105 oop JavaThread::current_park_blocker() {
3106 // Support for JSR-166 locks
3107 oop thread_oop = threadObj();
3108 if (thread_oop != NULL &&
3109 JDK_Version::current().supports_thread_park_blocker()) {
3110 return java_lang_Thread::park_blocker(thread_oop);
3111 }
3112 return NULL;
3113 }
3114
3115
3116 void JavaThread::print_stack_on(outputStream* st) {
3117 if (!has_last_Java_frame()) return;
3118 ResourceMark rm;
3119 HandleMark hm;
3120
3121 RegisterMap reg_map(this);
3122 vframe* start_vf = last_java_vframe(®_map);
3123 int count = 0;
3124 for (vframe* f = start_vf; f; f = f->sender() ) {
3125 if (f->is_java_frame()) {
3126 javaVFrame* jvf = javaVFrame::cast(f);
3127 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3128
3129 // Print out lock information
3130 if (JavaMonitorsInStackTrace) {
3131 jvf->print_lock_info_on(st, count);
3132 }
3133 } else {
3134 // Ignore non-Java frames
3135 }
3136
3137 // Bail-out case for too deep stacks
3138 count++;
3139 if (MaxJavaStackTraceDepth == count) return;
3140 }
3141 }
3142
3143
3144 // JVMTI PopFrame support
3145 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3146 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3147 if (in_bytes(size_in_bytes) != 0) {
3148 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3149 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3150 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3151 }
3152 }
3153
3154 void* JavaThread::popframe_preserved_args() {
3155 return _popframe_preserved_args;
3156 }
3157
3158 ByteSize JavaThread::popframe_preserved_args_size() {
3159 return in_ByteSize(_popframe_preserved_args_size);
3160 }
3161
3162 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3163 int sz = in_bytes(popframe_preserved_args_size());
3164 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3165 return in_WordSize(sz / wordSize);
3166 }
3167
3168 void JavaThread::popframe_free_preserved_args() {
3169 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3170 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3171 _popframe_preserved_args = NULL;
3172 _popframe_preserved_args_size = 0;
3173 }
3174
3175 #ifndef PRODUCT
3176
3177 void JavaThread::trace_frames() {
3178 tty->print_cr("[Describe stack]");
3179 int frame_no = 1;
3180 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3181 tty->print(" %d. ", frame_no++);
3182 fst.current()->print_value_on(tty,this);
3183 tty->cr();
3184 }
3185 }
3186
3187 class PrintAndVerifyOopClosure: public OopClosure {
3188 protected:
3189 template <class T> inline void do_oop_work(T* p) {
3190 oop obj = oopDesc::load_decode_heap_oop(p);
3191 if (obj == NULL) return;
3192 tty->print(INTPTR_FORMAT ": ", p);
3193 if (obj->is_oop_or_null()) {
3194 if (obj->is_objArray()) {
3195 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3196 } else {
3197 obj->print();
3198 }
3199 } else {
3200 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3201 }
3202 tty->cr();
3203 }
3204 public:
3205 virtual void do_oop(oop* p) { do_oop_work(p); }
3206 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3207 };
3208
3209
3210 static void oops_print(frame* f, const RegisterMap *map) {
3211 PrintAndVerifyOopClosure print;
3212 f->print_value();
3213 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3214 }
3215
3216 // Print our all the locations that contain oops and whether they are
3217 // valid or not. This useful when trying to find the oldest frame
3218 // where an oop has gone bad since the frame walk is from youngest to
3219 // oldest.
3220 void JavaThread::trace_oops() {
3221 tty->print_cr("[Trace oops]");
3222 frames_do(oops_print);
3223 }
3224
3225
3226 #ifdef ASSERT
3227 // Print or validate the layout of stack frames
3228 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3229 ResourceMark rm;
3230 PRESERVE_EXCEPTION_MARK;
3231 FrameValues values;
3232 int frame_no = 0;
3233 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3234 fst.current()->describe(values, ++frame_no);
3235 if (depth == frame_no) break;
3236 }
3237 if (validate_only) {
3238 values.validate();
3239 } else {
3240 tty->print_cr("[Describe stack layout]");
3241 values.print(this);
3242 }
3243 }
3244 #endif
3245
3246 void JavaThread::trace_stack_from(vframe* start_vf) {
3247 ResourceMark rm;
3248 int vframe_no = 1;
3249 for (vframe* f = start_vf; f; f = f->sender() ) {
3250 if (f->is_java_frame()) {
3251 javaVFrame::cast(f)->print_activation(vframe_no++);
3252 } else {
3253 f->print();
3254 }
3255 if (vframe_no > StackPrintLimit) {
3256 tty->print_cr("...<more frames>...");
3257 return;
3258 }
3259 }
3260 }
3261
3262
3263 void JavaThread::trace_stack() {
3264 if (!has_last_Java_frame()) return;
3265 ResourceMark rm;
3266 HandleMark hm;
3267 RegisterMap reg_map(this);
3268 trace_stack_from(last_java_vframe(®_map));
3269 }
3270
3271
3272 #endif // PRODUCT
3273
3274
3275 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3276 assert(reg_map != NULL, "a map must be given");
3277 frame f = last_frame();
3278 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3279 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3280 }
3281 return NULL;
3282 }
3283
3284
3285 Klass* JavaThread::security_get_caller_class(int depth) {
3286 vframeStream vfst(this);
3287 vfst.security_get_caller_frame(depth);
3288 if (!vfst.at_end()) {
3289 return vfst.method()->method_holder();
3290 }
3291 return NULL;
3292 }
3293
3294 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3295 assert(thread->is_Compiler_thread(), "must be compiler thread");
3296 CompileBroker::compiler_thread_loop();
3297 }
3298
3299 // Create a CompilerThread
3300 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3301 : JavaThread(&compiler_thread_entry) {
3302 _env = NULL;
3303 _log = NULL;
3304 _task = NULL;
3305 _queue = queue;
3306 _counters = counters;
3307 _buffer_blob = NULL;
3308 _scanned_nmethod = NULL;
3309 _compiler = NULL;
3310
3311 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3312 resource_area()->bias_to(mtCompiler);
3313
3314 #ifndef PRODUCT
3315 _ideal_graph_printer = NULL;
3316 #endif
3317 }
3318
3319 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3320 JavaThread::oops_do(f, cld_f, cf);
3321 if (_scanned_nmethod != NULL && cf != NULL) {
3322 // Safepoints can occur when the sweeper is scanning an nmethod so
3323 // process it here to make sure it isn't unloaded in the middle of
3324 // a scan.
3325 cf->do_code_blob(_scanned_nmethod);
3326 }
3327 }
3328
3329
3330 // ======= Threads ========
3331
3332 // The Threads class links together all active threads, and provides
3333 // operations over all threads. It is protected by its own Mutex
3334 // lock, which is also used in other contexts to protect thread
3335 // operations from having the thread being operated on from exiting
3336 // and going away unexpectedly (e.g., safepoint synchronization)
3337
3338 JavaThread* Threads::_thread_list = NULL;
3339 int Threads::_number_of_threads = 0;
3340 int Threads::_number_of_non_daemon_threads = 0;
3341 int Threads::_return_code = 0;
3342 size_t JavaThread::_stack_size_at_create = 0;
3343 #ifdef ASSERT
3344 bool Threads::_vm_complete = false;
3345 #endif
3346
3347 // All JavaThreads
3348 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3349
3350 void Threads::java_threads_do(ThreadClosure* tc) {
3351 assert_locked_or_safepoint(Threads_lock);
3352 ALL_JAVA_THREADS(p) {
3353 tc->do_thread(p);
3354 }
3355 }
3356
3357 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3358 void Threads::threads_do(ThreadClosure* tc) {
3359 assert_locked_or_safepoint(Threads_lock);
3360 // ALL_JAVA_THREADS iterates through all JavaThreads
3361 ALL_JAVA_THREADS(p) {
3362 tc->do_thread(p);
3363 }
3364 // Someday we could have a table or list of all non-JavaThreads.
3365 // For now, just manually iterate through them.
3366 tc->do_thread(VMThread::vm_thread());
3367 Universe::heap()->gc_threads_do(tc);
3368 WatcherThread *wt = WatcherThread::watcher_thread();
3369 // Strictly speaking, the following NULL check isn't sufficient to make sure
3370 // the data for WatcherThread is still valid upon being examined. However,
3371 // considering that WatchThread terminates when the VM is on the way to
3372 // exit at safepoint, the chance of the above is extremely small. The right
3373 // way to prevent termination of WatcherThread would be to acquire
3374 // Terminator_lock, but we can't do that without violating the lock rank
3375 // checking in some cases.
3376 if (wt != NULL)
3377 tc->do_thread(wt);
3378
3379 #if INCLUDE_JFR
3380 Thread* sampler_thread = Jfr::sampler_thread();
3381 if (sampler_thread != NULL) {
3382 tc->do_thread(sampler_thread);
3383 }
3384
3385 #endif
3386
3387 // If CompilerThreads ever become non-JavaThreads, add them here
3388 }
3389
3390 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3391
3392 extern void JDK_Version_init();
3393
3394 // Preinitialize version info.
3395 VM_Version::early_initialize();
3396
3397 // Check version
3398 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3399
3400 // Initialize the output stream module
3401 ostream_init();
3402
3403 // Process java launcher properties.
3404 Arguments::process_sun_java_launcher_properties(args);
3405
3406 // Initialize the os module before using TLS
3407 os::init();
3408
3409 // Initialize system properties.
3410 Arguments::init_system_properties();
3411
3412 // So that JDK version can be used as a discrimintor when parsing arguments
3413 JDK_Version_init();
3414
3415 // Update/Initialize System properties after JDK version number is known
3416 Arguments::init_version_specific_system_properties();
3417
3418 // Parse arguments
3419 // Note: this internally calls os::init_container_support()
3420 jint parse_result = Arguments::parse(args);
3421 if (parse_result != JNI_OK) return parse_result;
3422
3423 os::init_before_ergo();
3424
3425 jint ergo_result = Arguments::apply_ergo();
3426 if (ergo_result != JNI_OK) return ergo_result;
3427
3428 if (PauseAtStartup) {
3429 os::pause();
3430 }
3431
3432 #ifndef USDT2
3433 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3434 #else /* USDT2 */
3435 HOTSPOT_VM_INIT_BEGIN();
3436 #endif /* USDT2 */
3437
3438 // Record VM creation timing statistics
3439 TraceVmCreationTime create_vm_timer;
3440 create_vm_timer.start();
3441
3442 // Timing (must come after argument parsing)
3443 TraceTime timer("Create VM", TraceStartupTime);
3444
3445 // Initialize the os module after parsing the args
3446 jint os_init_2_result = os::init_2();
3447 if (os_init_2_result != JNI_OK) return os_init_2_result;
3448
3449 jint adjust_after_os_result = Arguments::adjust_after_os();
3450 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3451
3452 // intialize TLS
3453 ThreadLocalStorage::init();
3454
3455 // Initialize output stream logging
3456 ostream_init_log();
3457
3458 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3459 // Must be before create_vm_init_agents()
3460 if (Arguments::init_libraries_at_startup()) {
3461 convert_vm_init_libraries_to_agents();
3462 }
3463
3464 // Launch -agentlib/-agentpath and converted -Xrun agents
3465 if (Arguments::init_agents_at_startup()) {
3466 create_vm_init_agents();
3467 }
3468
3469 // Initialize Threads state
3470 _thread_list = NULL;
3471 _number_of_threads = 0;
3472 _number_of_non_daemon_threads = 0;
3473
3474 // Initialize global data structures and create system classes in heap
3475 vm_init_globals();
3476
3477 // Attach the main thread to this os thread
3478 JavaThread* main_thread = new JavaThread();
3479 main_thread->set_thread_state(_thread_in_vm);
3480 // must do this before set_active_handles and initialize_thread_local_storage
3481 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3482 // change the stack size recorded here to one based on the java thread
3483 // stacksize. This adjusted size is what is used to figure the placement
3484 // of the guard pages.
3485 main_thread->record_stack_base_and_size();
3486 main_thread->initialize_thread_local_storage();
3487
3488 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3489
3490 if (!main_thread->set_as_starting_thread()) {
3491 vm_shutdown_during_initialization(
3492 "Failed necessary internal allocation. Out of swap space");
3493 delete main_thread;
3494 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3495 return JNI_ENOMEM;
3496 }
3497
3498 // Enable guard page *after* os::create_main_thread(), otherwise it would
3499 // crash Linux VM, see notes in os_linux.cpp.
3500 main_thread->create_stack_guard_pages();
3501
3502 // Initialize Java-Level synchronization subsystem
3503 ObjectMonitor::Initialize() ;
3504
3505 // Initialize global modules
3506 jint status = init_globals();
3507 if (status != JNI_OK) {
3508 delete main_thread;
3509 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3510 return status;
3511 }
3512
3513 JFR_ONLY(Jfr::on_vm_init();)
3514
3515 // Should be done after the heap is fully created
3516 main_thread->cache_global_variables();
3517
3518 HandleMark hm;
3519
3520 { MutexLocker mu(Threads_lock);
3521 Threads::add(main_thread);
3522 }
3523
3524 // Any JVMTI raw monitors entered in onload will transition into
3525 // real raw monitor. VM is setup enough here for raw monitor enter.
3526 JvmtiExport::transition_pending_onload_raw_monitors();
3527
3528 // Create the VMThread
3529 { TraceTime timer("Start VMThread", TraceStartupTime);
3530 VMThread::create();
3531 Thread* vmthread = VMThread::vm_thread();
3532
3533 if (!os::create_thread(vmthread, os::vm_thread))
3534 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3535
3536 // Wait for the VM thread to become ready, and VMThread::run to initialize
3537 // Monitors can have spurious returns, must always check another state flag
3538 {
3539 MutexLocker ml(Notify_lock);
3540 os::start_thread(vmthread);
3541 while (vmthread->active_handles() == NULL) {
3542 Notify_lock->wait();
3543 }
3544 }
3545 }
3546
3547 assert (Universe::is_fully_initialized(), "not initialized");
3548 if (VerifyDuringStartup) {
3549 // Make sure we're starting with a clean slate.
3550 VM_Verify verify_op;
3551 VMThread::execute(&verify_op);
3552 }
3553
3554 EXCEPTION_MARK;
3555
3556 // At this point, the Universe is initialized, but we have not executed
3557 // any byte code. Now is a good time (the only time) to dump out the
3558 // internal state of the JVM for sharing.
3559 if (DumpSharedSpaces) {
3560 MetaspaceShared::preload_and_dump(CHECK_0);
3561 ShouldNotReachHere();
3562 }
3563
3564 // Always call even when there are not JVMTI environments yet, since environments
3565 // may be attached late and JVMTI must track phases of VM execution
3566 JvmtiExport::enter_start_phase();
3567
3568 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3569 JvmtiExport::post_vm_start();
3570
3571 {
3572 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3573
3574 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3575 create_vm_init_libraries();
3576 }
3577
3578 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3579
3580 // Initialize java_lang.System (needed before creating the thread)
3581 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3582 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3583 Handle thread_group = create_initial_thread_group(CHECK_0);
3584 Universe::set_main_thread_group(thread_group());
3585 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3586 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3587 main_thread->set_threadObj(thread_object);
3588 // Set thread status to running since main thread has
3589 // been started and running.
3590 java_lang_Thread::set_thread_status(thread_object,
3591 java_lang_Thread::RUNNABLE);
3592
3593 // The VM creates & returns objects of this class. Make sure it's initialized.
3594 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3595
3596 // The VM preresolves methods to these classes. Make sure that they get initialized
3597 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3598 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3599 call_initializeSystemClass(CHECK_0);
3600
3601 // get the Java runtime name after java.lang.System is initialized
3602 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3603 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3604
3605 // an instance of OutOfMemory exception has been allocated earlier
3606 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3607 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3608 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3609 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3610 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3611 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3612 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3613 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3614 }
3615
3616 // See : bugid 4211085.
3617 // Background : the static initializer of java.lang.Compiler tries to read
3618 // property"java.compiler" and read & write property "java.vm.info".
3619 // When a security manager is installed through the command line
3620 // option "-Djava.security.manager", the above properties are not
3621 // readable and the static initializer for java.lang.Compiler fails
3622 // resulting in a NoClassDefFoundError. This can happen in any
3623 // user code which calls methods in java.lang.Compiler.
3624 // Hack : the hack is to pre-load and initialize this class, so that only
3625 // system domains are on the stack when the properties are read.
3626 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3627 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3628 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3629 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3630 // Once that is done, we should remove this hack.
3631 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3632
3633 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3634 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3635 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3636 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3637 // This should also be taken out as soon as 4211383 gets fixed.
3638 reset_vm_info_property(CHECK_0);
3639
3640 quicken_jni_functions();
3641
3642 // Set flag that basic initialization has completed. Used by exceptions and various
3643 // debug stuff, that does not work until all basic classes have been initialized.
3644 set_init_completed();
3645
3646 Metaspace::post_initialize();
3647
3648 #ifndef USDT2
3649 HS_DTRACE_PROBE(hotspot, vm__init__end);
3650 #else /* USDT2 */
3651 HOTSPOT_VM_INIT_END();
3652 #endif /* USDT2 */
3653
3654 // record VM initialization completion time
3655 #if INCLUDE_MANAGEMENT
3656 Management::record_vm_init_completed();
3657 #endif // INCLUDE_MANAGEMENT
3658
3659 // Compute system loader. Note that this has to occur after set_init_completed, since
3660 // valid exceptions may be thrown in the process.
3661 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3662 // set_init_completed has just been called, causing exceptions not to be shortcut
3663 // anymore. We call vm_exit_during_initialization directly instead.
3664 SystemDictionary::compute_java_system_loader(THREAD);
3665 if (HAS_PENDING_EXCEPTION) {
3666 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3667 }
3668
3669 #if INCLUDE_ALL_GCS
3670 // Support for ConcurrentMarkSweep. This should be cleaned up
3671 // and better encapsulated. The ugly nested if test would go away
3672 // once things are properly refactored. XXX YSR
3673 if (UseConcMarkSweepGC || UseG1GC || UseShenandoahGC) {
3674 if (UseConcMarkSweepGC) {
3675 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3676 } else if (UseShenandoahGC) {
3677 ShenandoahControlThread::makeSurrogateLockerThread(THREAD);
3678 } else {
3679 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3680 }
3681 if (HAS_PENDING_EXCEPTION) {
3682 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3683 }
3684 }
3685 #endif // INCLUDE_ALL_GCS
3686
3687 // Always call even when there are not JVMTI environments yet, since environments
3688 // may be attached late and JVMTI must track phases of VM execution
3689 JvmtiExport::enter_live_phase();
3690
3691 // Signal Dispatcher needs to be started before VMInit event is posted
3692 os::signal_init();
3693
3694 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3695 if (!DisableAttachMechanism) {
3696 AttachListener::vm_start();
3697 if (StartAttachListener || AttachListener::init_at_startup()) {
3698 AttachListener::init();
3699 }
3700 }
3701
3702 // Launch -Xrun agents
3703 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3704 // back-end can launch with -Xdebug -Xrunjdwp.
3705 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3706 create_vm_init_libraries();
3707 }
3708
3709 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3710 JvmtiExport::post_vm_initialized();
3711
3712 JFR_ONLY(Jfr::on_vm_start();)
3713
3714 if (CleanChunkPoolAsync) {
3715 Chunk::start_chunk_pool_cleaner_task();
3716 }
3717
3718 // initialize compiler(s)
3719 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3720 CompileBroker::compilation_init();
3721 #endif
3722
3723 if (EnableInvokeDynamic) {
3724 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3725 // It is done after compilers are initialized, because otherwise compilations of
3726 // signature polymorphic MH intrinsics can be missed
3727 // (see SystemDictionary::find_method_handle_intrinsic).
3728 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3729 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3730 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3731 }
3732
3733 #if INCLUDE_MANAGEMENT
3734 Management::initialize(THREAD);
3735 #endif // INCLUDE_MANAGEMENT
3736
3737 if (HAS_PENDING_EXCEPTION) {
3738 // management agent fails to start possibly due to
3739 // configuration problem and is responsible for printing
3740 // stack trace if appropriate. Simply exit VM.
3741 vm_exit(1);
3742 }
3743
3744 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3745 if (MemProfiling) MemProfiler::engage();
3746 StatSampler::engage();
3747 if (CheckJNICalls) JniPeriodicChecker::engage();
3748
3749 BiasedLocking::init();
3750
3751 #if INCLUDE_RTM_OPT
3752 RTMLockingCounters::init();
3753 #endif
3754
3755 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3756 call_postVMInitHook(THREAD);
3757 // The Java side of PostVMInitHook.run must deal with all
3758 // exceptions and provide means of diagnosis.
3759 if (HAS_PENDING_EXCEPTION) {
3760 CLEAR_PENDING_EXCEPTION;
3761 }
3762 }
3763
3764 {
3765 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3766 // Make sure the watcher thread can be started by WatcherThread::start()
3767 // or by dynamic enrollment.
3768 WatcherThread::make_startable();
3769 // Start up the WatcherThread if there are any periodic tasks
3770 // NOTE: All PeriodicTasks should be registered by now. If they
3771 // aren't, late joiners might appear to start slowly (we might
3772 // take a while to process their first tick).
3773 if (PeriodicTask::num_tasks() > 0) {
3774 WatcherThread::start();
3775 }
3776 }
3777
3778 create_vm_timer.end();
3779 #ifdef ASSERT
3780 _vm_complete = true;
3781 #endif
3782 return JNI_OK;
3783 }
3784
3785 // type for the Agent_OnLoad and JVM_OnLoad entry points
3786 extern "C" {
3787 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3788 }
3789 // Find a command line agent library and return its entry point for
3790 // -agentlib: -agentpath: -Xrun
3791 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3792 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3793 OnLoadEntry_t on_load_entry = NULL;
3794 void *library = NULL;
3795
3796 if (!agent->valid()) {
3797 char buffer[JVM_MAXPATHLEN];
3798 char ebuf[1024];
3799 const char *name = agent->name();
3800 const char *msg = "Could not find agent library ";
3801
3802 // First check to see if agent is statically linked into executable
3803 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3804 library = agent->os_lib();
3805 } else if (agent->is_absolute_path()) {
3806 library = os::dll_load(name, ebuf, sizeof ebuf);
3807 if (library == NULL) {
3808 const char *sub_msg = " in absolute path, with error: ";
3809 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3810 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3811 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3812 // If we can't find the agent, exit.
3813 vm_exit_during_initialization(buf, NULL);
3814 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3815 }
3816 } else {
3817 // Try to load the agent from the standard dll directory
3818 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3819 name)) {
3820 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3821 }
3822 if (library == NULL) { // Try the local directory
3823 char ns[1] = {0};
3824 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3825 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3826 }
3827 if (library == NULL) {
3828 const char *sub_msg = " on the library path, with error: ";
3829 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3830 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3831 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3832 // If we can't find the agent, exit.
3833 vm_exit_during_initialization(buf, NULL);
3834 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3835 }
3836 }
3837 }
3838 agent->set_os_lib(library);
3839 agent->set_valid();
3840 }
3841
3842 // Find the OnLoad function.
3843 on_load_entry =
3844 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3845 false,
3846 on_load_symbols,
3847 num_symbol_entries));
3848 return on_load_entry;
3849 }
3850
3851 // Find the JVM_OnLoad entry point
3852 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3853 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3854 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3855 }
3856
3857 // Find the Agent_OnLoad entry point
3858 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3859 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3860 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3861 }
3862
3863 // For backwards compatibility with -Xrun
3864 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3865 // treated like -agentpath:
3866 // Must be called before agent libraries are created
3867 void Threads::convert_vm_init_libraries_to_agents() {
3868 AgentLibrary* agent;
3869 AgentLibrary* next;
3870
3871 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3872 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3873 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3874
3875 // If there is an JVM_OnLoad function it will get called later,
3876 // otherwise see if there is an Agent_OnLoad
3877 if (on_load_entry == NULL) {
3878 on_load_entry = lookup_agent_on_load(agent);
3879 if (on_load_entry != NULL) {
3880 // switch it to the agent list -- so that Agent_OnLoad will be called,
3881 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3882 Arguments::convert_library_to_agent(agent);
3883 } else {
3884 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3885 }
3886 }
3887 }
3888 }
3889
3890 // Create agents for -agentlib: -agentpath: and converted -Xrun
3891 // Invokes Agent_OnLoad
3892 // Called very early -- before JavaThreads exist
3893 void Threads::create_vm_init_agents() {
3894 extern struct JavaVM_ main_vm;
3895 AgentLibrary* agent;
3896
3897 JvmtiExport::enter_onload_phase();
3898
3899 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3900 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3901
3902 if (on_load_entry != NULL) {
3903 // Invoke the Agent_OnLoad function
3904 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3905 if (err != JNI_OK) {
3906 vm_exit_during_initialization("agent library failed to init", agent->name());
3907 }
3908 } else {
3909 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3910 }
3911 }
3912 JvmtiExport::enter_primordial_phase();
3913 }
3914
3915 extern "C" {
3916 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3917 }
3918
3919 void Threads::shutdown_vm_agents() {
3920 // Send any Agent_OnUnload notifications
3921 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3922 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3923 extern struct JavaVM_ main_vm;
3924 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3925
3926 // Find the Agent_OnUnload function.
3927 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3928 os::find_agent_function(agent,
3929 false,
3930 on_unload_symbols,
3931 num_symbol_entries));
3932
3933 // Invoke the Agent_OnUnload function
3934 if (unload_entry != NULL) {
3935 JavaThread* thread = JavaThread::current();
3936 ThreadToNativeFromVM ttn(thread);
3937 HandleMark hm(thread);
3938 (*unload_entry)(&main_vm);
3939 }
3940 }
3941 }
3942
3943 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3944 // Invokes JVM_OnLoad
3945 void Threads::create_vm_init_libraries() {
3946 extern struct JavaVM_ main_vm;
3947 AgentLibrary* agent;
3948
3949 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3950 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3951
3952 if (on_load_entry != NULL) {
3953 // Invoke the JVM_OnLoad function
3954 JavaThread* thread = JavaThread::current();
3955 ThreadToNativeFromVM ttn(thread);
3956 HandleMark hm(thread);
3957 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3958 if (err != JNI_OK) {
3959 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3960 }
3961 } else {
3962 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3963 }
3964 }
3965 }
3966
3967 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3968 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3969
3970 JavaThread* java_thread = NULL;
3971 // Sequential search for now. Need to do better optimization later.
3972 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3973 oop tobj = thread->threadObj();
3974 if (!thread->is_exiting() &&
3975 tobj != NULL &&
3976 java_tid == java_lang_Thread::thread_id(tobj)) {
3977 java_thread = thread;
3978 break;
3979 }
3980 }
3981 return java_thread;
3982 }
3983
3984
3985 // Last thread running calls java.lang.Shutdown.shutdown()
3986 void JavaThread::invoke_shutdown_hooks() {
3987 HandleMark hm(this);
3988
3989 // We could get here with a pending exception, if so clear it now.
3990 if (this->has_pending_exception()) {
3991 this->clear_pending_exception();
3992 }
3993
3994 EXCEPTION_MARK;
3995 Klass* k =
3996 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3997 THREAD);
3998 if (k != NULL) {
3999 // SystemDictionary::resolve_or_null will return null if there was
4000 // an exception. If we cannot load the Shutdown class, just don't
4001 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4002 // and finalizers (if runFinalizersOnExit is set) won't be run.
4003 // Note that if a shutdown hook was registered or runFinalizersOnExit
4004 // was called, the Shutdown class would have already been loaded
4005 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
4006 instanceKlassHandle shutdown_klass (THREAD, k);
4007 JavaValue result(T_VOID);
4008 JavaCalls::call_static(&result,
4009 shutdown_klass,
4010 vmSymbols::shutdown_method_name(),
4011 vmSymbols::void_method_signature(),
4012 THREAD);
4013 }
4014 CLEAR_PENDING_EXCEPTION;
4015 }
4016
4017 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4018 // the program falls off the end of main(). Another VM exit path is through
4019 // vm_exit() when the program calls System.exit() to return a value or when
4020 // there is a serious error in VM. The two shutdown paths are not exactly
4021 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4022 // and VM_Exit op at VM level.
4023 //
4024 // Shutdown sequence:
4025 // + Shutdown native memory tracking if it is on
4026 // + Wait until we are the last non-daemon thread to execute
4027 // <-- every thing is still working at this moment -->
4028 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4029 // shutdown hooks, run finalizers if finalization-on-exit
4030 // + Call before_exit(), prepare for VM exit
4031 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4032 // currently the only user of this mechanism is File.deleteOnExit())
4033 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
4034 // post thread end and vm death events to JVMTI,
4035 // stop signal thread
4036 // + Call JavaThread::exit(), it will:
4037 // > release JNI handle blocks, remove stack guard pages
4038 // > remove this thread from Threads list
4039 // <-- no more Java code from this thread after this point -->
4040 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4041 // the compiler threads at safepoint
4042 // <-- do not use anything that could get blocked by Safepoint -->
4043 // + Disable tracing at JNI/JVM barriers
4044 // + Set _vm_exited flag for threads that are still running native code
4045 // + Delete this thread
4046 // + Call exit_globals()
4047 // > deletes tty
4048 // > deletes PerfMemory resources
4049 // + Return to caller
4050
4051 bool Threads::destroy_vm() {
4052 JavaThread* thread = JavaThread::current();
4053
4054 #ifdef ASSERT
4055 _vm_complete = false;
4056 #endif
4057 // Wait until we are the last non-daemon thread to execute
4058 { MutexLocker nu(Threads_lock);
4059 while (Threads::number_of_non_daemon_threads() > 1 )
4060 // This wait should make safepoint checks, wait without a timeout,
4061 // and wait as a suspend-equivalent condition.
4062 //
4063 // Note: If the FlatProfiler is running and this thread is waiting
4064 // for another non-daemon thread to finish, then the FlatProfiler
4065 // is waiting for the external suspend request on this thread to
4066 // complete. wait_for_ext_suspend_completion() will eventually
4067 // timeout, but that takes time. Making this wait a suspend-
4068 // equivalent condition solves that timeout problem.
4069 //
4070 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4071 Mutex::_as_suspend_equivalent_flag);
4072 }
4073
4074 EventShutdown e;
4075 if (e.should_commit()) {
4076 e.set_reason("No remaining non-daemon Java threads");
4077 e.commit();
4078 }
4079
4080 // Hang forever on exit if we are reporting an error.
4081 if (ShowMessageBoxOnError && is_error_reported()) {
4082 os::infinite_sleep();
4083 }
4084 os::wait_for_keypress_at_exit();
4085
4086 if (JDK_Version::is_jdk12x_version()) {
4087 // We are the last thread running, so check if finalizers should be run.
4088 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
4089 HandleMark rm(thread);
4090 Universe::run_finalizers_on_exit();
4091 } else {
4092 // run Java level shutdown hooks
4093 thread->invoke_shutdown_hooks();
4094 }
4095
4096 before_exit(thread);
4097
4098 thread->exit(true);
4099
4100 // Stop VM thread.
4101 {
4102 // 4945125 The vm thread comes to a safepoint during exit.
4103 // GC vm_operations can get caught at the safepoint, and the
4104 // heap is unparseable if they are caught. Grab the Heap_lock
4105 // to prevent this. The GC vm_operations will not be able to
4106 // queue until after the vm thread is dead. After this point,
4107 // we'll never emerge out of the safepoint before the VM exits.
4108
4109 MutexLocker ml(Heap_lock);
4110
4111 VMThread::wait_for_vm_thread_exit();
4112 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4113 VMThread::destroy();
4114 }
4115
4116 // clean up ideal graph printers
4117 #if defined(COMPILER2) && !defined(PRODUCT)
4118 IdealGraphPrinter::clean_up();
4119 #endif
4120
4121 // Now, all Java threads are gone except daemon threads. Daemon threads
4122 // running Java code or in VM are stopped by the Safepoint. However,
4123 // daemon threads executing native code are still running. But they
4124 // will be stopped at native=>Java/VM barriers. Note that we can't
4125 // simply kill or suspend them, as it is inherently deadlock-prone.
4126
4127 #ifndef PRODUCT
4128 // disable function tracing at JNI/JVM barriers
4129 TraceJNICalls = false;
4130 TraceJVMCalls = false;
4131 TraceRuntimeCalls = false;
4132 #endif
4133
4134 VM_Exit::set_vm_exited();
4135
4136 notify_vm_shutdown();
4137
4138 delete thread;
4139
4140 // exit_globals() will delete tty
4141 exit_globals();
4142
4143 return true;
4144 }
4145
4146
4147 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4148 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4149 return is_supported_jni_version(version);
4150 }
4151
4152
4153 jboolean Threads::is_supported_jni_version(jint version) {
4154 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4155 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4156 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4157 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4158 return JNI_FALSE;
4159 }
4160
4161
4162 void Threads::add(JavaThread* p, bool force_daemon) {
4163 // The threads lock must be owned at this point
4164 assert_locked_or_safepoint(Threads_lock);
4165
4166 // See the comment for this method in thread.hpp for its purpose and
4167 // why it is called here.
4168 p->initialize_queues();
4169 p->set_next(_thread_list);
4170 _thread_list = p;
4171 _number_of_threads++;
4172 oop threadObj = p->threadObj();
4173 bool daemon = true;
4174 // Bootstrapping problem: threadObj can be null for initial
4175 // JavaThread (or for threads attached via JNI)
4176 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4177 _number_of_non_daemon_threads++;
4178 daemon = false;
4179 }
4180
4181 ThreadService::add_thread(p, daemon);
4182
4183 // Possible GC point.
4184 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4185 }
4186
4187 void Threads::remove(JavaThread* p) {
4188 // Extra scope needed for Thread_lock, so we can check
4189 // that we do not remove thread without safepoint code notice
4190 { MutexLocker ml(Threads_lock);
4191
4192 assert(includes(p), "p must be present");
4193
4194 JavaThread* current = _thread_list;
4195 JavaThread* prev = NULL;
4196
4197 while (current != p) {
4198 prev = current;
4199 current = current->next();
4200 }
4201
4202 if (prev) {
4203 prev->set_next(current->next());
4204 } else {
4205 _thread_list = p->next();
4206 }
4207 _number_of_threads--;
4208 oop threadObj = p->threadObj();
4209 bool daemon = true;
4210 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4211 _number_of_non_daemon_threads--;
4212 daemon = false;
4213
4214 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4215 // on destroy_vm will wake up.
4216 if (number_of_non_daemon_threads() == 1)
4217 Threads_lock->notify_all();
4218 }
4219 ThreadService::remove_thread(p, daemon);
4220
4221 // Make sure that safepoint code disregard this thread. This is needed since
4222 // the thread might mess around with locks after this point. This can cause it
4223 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4224 // of this thread since it is removed from the queue.
4225 p->set_terminated_value();
4226 } // unlock Threads_lock
4227
4228 // Since Events::log uses a lock, we grab it outside the Threads_lock
4229 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4230 }
4231
4232 // Threads_lock must be held when this is called (or must be called during a safepoint)
4233 bool Threads::includes(JavaThread* p) {
4234 assert(Threads_lock->is_locked(), "sanity check");
4235 ALL_JAVA_THREADS(q) {
4236 if (q == p ) {
4237 return true;
4238 }
4239 }
4240 return false;
4241 }
4242
4243 // Operations on the Threads list for GC. These are not explicitly locked,
4244 // but the garbage collector must provide a safe context for them to run.
4245 // In particular, these things should never be called when the Threads_lock
4246 // is held by some other thread. (Note: the Safepoint abstraction also
4247 // uses the Threads_lock to gurantee this property. It also makes sure that
4248 // all threads gets blocked when exiting or starting).
4249
4250 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4251 ALL_JAVA_THREADS(p) {
4252 p->oops_do(f, cld_f, cf);
4253 }
4254 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4255 }
4256
4257 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4258 // Introduce a mechanism allowing parallel threads to claim threads as
4259 // root groups. Overhead should be small enough to use all the time,
4260 // even in sequential code.
4261 SharedHeap* sh = SharedHeap::heap();
4262 // Cannot yet substitute active_workers for n_par_threads
4263 // because of G1CollectedHeap::verify() use of
4264 // SharedHeap::process_roots(). n_par_threads == 0 will
4265 // turn off parallelism in process_roots while active_workers
4266 // is being used for parallelism elsewhere.
4267 bool is_par = sh->n_par_threads() > 0;
4268 assert(!is_par ||
4269 (SharedHeap::heap()->n_par_threads() ==
4270 SharedHeap::heap()->workers()->active_workers()
4271 || UseShenandoahGC), "Mismatch");
4272 int cp = SharedHeap::heap()->strong_roots_parity();
4273 ALL_JAVA_THREADS(p) {
4274 if (p->claim_oops_do(is_par, cp)) {
4275 p->oops_do(f, cld_f, cf);
4276 }
4277 }
4278 VMThread* vmt = VMThread::vm_thread();
4279 if (vmt->claim_oops_do(is_par, cp)) {
4280 vmt->oops_do(f, cld_f, cf);
4281 }
4282 }
4283
4284 #if INCLUDE_ALL_GCS
4285 // Used by ParallelScavenge
4286 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4287 ALL_JAVA_THREADS(p) {
4288 q->enqueue(new ThreadRootsTask(p));
4289 }
4290 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4291 }
4292
4293 // Used by Parallel Old
4294 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4295 ALL_JAVA_THREADS(p) {
4296 q->enqueue(new ThreadRootsMarkingTask(p));
4297 }
4298 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4299 }
4300 #endif // INCLUDE_ALL_GCS
4301
4302 void Threads::nmethods_do(CodeBlobClosure* cf) {
4303 ALL_JAVA_THREADS(p) {
4304 p->nmethods_do(cf);
4305 }
4306 VMThread::vm_thread()->nmethods_do(cf);
4307 }
4308
4309 void Threads::metadata_do(void f(Metadata*)) {
4310 ALL_JAVA_THREADS(p) {
4311 p->metadata_do(f);
4312 }
4313 }
4314
4315 void Threads::gc_epilogue() {
4316 ALL_JAVA_THREADS(p) {
4317 p->gc_epilogue();
4318 }
4319 }
4320
4321 void Threads::gc_prologue() {
4322 ALL_JAVA_THREADS(p) {
4323 p->gc_prologue();
4324 }
4325 }
4326
4327 void Threads::deoptimized_wrt_marked_nmethods() {
4328 ALL_JAVA_THREADS(p) {
4329 p->deoptimized_wrt_marked_nmethods();
4330 }
4331 }
4332
4333
4334 // Get count Java threads that are waiting to enter the specified monitor.
4335 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4336 address monitor, bool doLock) {
4337 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4338 "must grab Threads_lock or be at safepoint");
4339 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4340
4341 int i = 0;
4342 {
4343 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4344 ALL_JAVA_THREADS(p) {
4345 if (p->is_Compiler_thread()) continue;
4346
4347 address pending = (address)p->current_pending_monitor();
4348 if (pending == monitor) { // found a match
4349 if (i < count) result->append(p); // save the first count matches
4350 i++;
4351 }
4352 }
4353 }
4354 return result;
4355 }
4356
4357
4358 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4359 assert(doLock ||
4360 Threads_lock->owned_by_self() ||
4361 SafepointSynchronize::is_at_safepoint(),
4362 "must grab Threads_lock or be at safepoint");
4363
4364 // NULL owner means not locked so we can skip the search
4365 if (owner == NULL) return NULL;
4366
4367 {
4368 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4369 ALL_JAVA_THREADS(p) {
4370 // first, see if owner is the address of a Java thread
4371 if (owner == (address)p) return p;
4372 }
4373 }
4374 // Cannot assert on lack of success here since this function may be
4375 // used by code that is trying to report useful problem information
4376 // like deadlock detection.
4377 if (UseHeavyMonitors) return NULL;
4378
4379 //
4380 // If we didn't find a matching Java thread and we didn't force use of
4381 // heavyweight monitors, then the owner is the stack address of the
4382 // Lock Word in the owning Java thread's stack.
4383 //
4384 JavaThread* the_owner = NULL;
4385 {
4386 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4387 ALL_JAVA_THREADS(q) {
4388 if (q->is_lock_owned(owner)) {
4389 the_owner = q;
4390 break;
4391 }
4392 }
4393 }
4394 // cannot assert on lack of success here; see above comment
4395 return the_owner;
4396 }
4397
4398 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4399 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4400 char buf[32];
4401 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4402
4403 st->print_cr("Full thread dump %s (%s %s):",
4404 Abstract_VM_Version::vm_name(),
4405 Abstract_VM_Version::vm_release(),
4406 Abstract_VM_Version::vm_info_string()
4407 );
4408 st->cr();
4409
4410 #if INCLUDE_ALL_GCS
4411 // Dump concurrent locks
4412 ConcurrentLocksDump concurrent_locks;
4413 if (print_concurrent_locks) {
4414 concurrent_locks.dump_at_safepoint();
4415 }
4416 #endif // INCLUDE_ALL_GCS
4417
4418 ALL_JAVA_THREADS(p) {
4419 ResourceMark rm;
4420 p->print_on(st);
4421 if (print_stacks) {
4422 if (internal_format) {
4423 p->trace_stack();
4424 } else {
4425 p->print_stack_on(st);
4426 }
4427 }
4428 st->cr();
4429 #if INCLUDE_ALL_GCS
4430 if (print_concurrent_locks) {
4431 concurrent_locks.print_locks_on(p, st);
4432 }
4433 #endif // INCLUDE_ALL_GCS
4434 }
4435
4436 VMThread::vm_thread()->print_on(st);
4437 st->cr();
4438 Universe::heap()->print_gc_threads_on(st);
4439 WatcherThread* wt = WatcherThread::watcher_thread();
4440 if (wt != NULL) {
4441 wt->print_on(st);
4442 st->cr();
4443 }
4444 CompileBroker::print_compiler_threads_on(st);
4445 st->flush();
4446 }
4447
4448 // Threads::print_on_error() is called by fatal error handler. It's possible
4449 // that VM is not at safepoint and/or current thread is inside signal handler.
4450 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4451 // memory (even in resource area), it might deadlock the error handler.
4452 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4453 bool found_current = false;
4454 st->print_cr("Java Threads: ( => current thread )");
4455 ALL_JAVA_THREADS(thread) {
4456 bool is_current = (current == thread);
4457 found_current = found_current || is_current;
4458
4459 st->print("%s", is_current ? "=>" : " ");
4460
4461 st->print(PTR_FORMAT, thread);
4462 st->print(" ");
4463 thread->print_on_error(st, buf, buflen);
4464 st->cr();
4465 }
4466 st->cr();
4467
4468 st->print_cr("Other Threads:");
4469 if (VMThread::vm_thread()) {
4470 bool is_current = (current == VMThread::vm_thread());
4471 found_current = found_current || is_current;
4472 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4473
4474 st->print(PTR_FORMAT, VMThread::vm_thread());
4475 st->print(" ");
4476 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4477 st->cr();
4478 }
4479 WatcherThread* wt = WatcherThread::watcher_thread();
4480 if (wt != NULL) {
4481 bool is_current = (current == wt);
4482 found_current = found_current || is_current;
4483 st->print("%s", is_current ? "=>" : " ");
4484
4485 st->print(PTR_FORMAT, wt);
4486 st->print(" ");
4487 wt->print_on_error(st, buf, buflen);
4488 st->cr();
4489 }
4490 if (!found_current) {
4491 st->cr();
4492 st->print("=>" PTR_FORMAT " (exited) ", current);
4493 current->print_on_error(st, buf, buflen);
4494 st->cr();
4495 }
4496 }
4497
4498 // Internal SpinLock and Mutex
4499 // Based on ParkEvent
4500
4501 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4502 //
4503 // We employ SpinLocks _only for low-contention, fixed-length
4504 // short-duration critical sections where we're concerned
4505 // about native mutex_t or HotSpot Mutex:: latency.
4506 // The mux construct provides a spin-then-block mutual exclusion
4507 // mechanism.
4508 //
4509 // Testing has shown that contention on the ListLock guarding gFreeList
4510 // is common. If we implement ListLock as a simple SpinLock it's common
4511 // for the JVM to devolve to yielding with little progress. This is true
4512 // despite the fact that the critical sections protected by ListLock are
4513 // extremely short.
4514 //
4515 // TODO-FIXME: ListLock should be of type SpinLock.
4516 // We should make this a 1st-class type, integrated into the lock
4517 // hierarchy as leaf-locks. Critically, the SpinLock structure
4518 // should have sufficient padding to avoid false-sharing and excessive
4519 // cache-coherency traffic.
4520
4521
4522 typedef volatile int SpinLockT ;
4523
4524 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4525 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4526 return ; // normal fast-path return
4527 }
4528
4529 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4530 TEVENT (SpinAcquire - ctx) ;
4531 int ctr = 0 ;
4532 int Yields = 0 ;
4533 for (;;) {
4534 while (*adr != 0) {
4535 ++ctr ;
4536 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4537 if (Yields > 5) {
4538 os::naked_short_sleep(1);
4539 } else {
4540 os::NakedYield() ;
4541 ++Yields ;
4542 }
4543 } else {
4544 SpinPause() ;
4545 }
4546 }
4547 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4548 }
4549 }
4550
4551 void Thread::SpinRelease (volatile int * adr) {
4552 assert (*adr != 0, "invariant") ;
4553 OrderAccess::fence() ; // guarantee at least release consistency.
4554 // Roach-motel semantics.
4555 // It's safe if subsequent LDs and STs float "up" into the critical section,
4556 // but prior LDs and STs within the critical section can't be allowed
4557 // to reorder or float past the ST that releases the lock.
4558 *adr = 0 ;
4559 }
4560
4561 // muxAcquire and muxRelease:
4562 //
4563 // * muxAcquire and muxRelease support a single-word lock-word construct.
4564 // The LSB of the word is set IFF the lock is held.
4565 // The remainder of the word points to the head of a singly-linked list
4566 // of threads blocked on the lock.
4567 //
4568 // * The current implementation of muxAcquire-muxRelease uses its own
4569 // dedicated Thread._MuxEvent instance. If we're interested in
4570 // minimizing the peak number of extant ParkEvent instances then
4571 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4572 // as certain invariants were satisfied. Specifically, care would need
4573 // to be taken with regards to consuming unpark() "permits".
4574 // A safe rule of thumb is that a thread would never call muxAcquire()
4575 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4576 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4577 // consume an unpark() permit intended for monitorenter, for instance.
4578 // One way around this would be to widen the restricted-range semaphore
4579 // implemented in park(). Another alternative would be to provide
4580 // multiple instances of the PlatformEvent() for each thread. One
4581 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4582 //
4583 // * Usage:
4584 // -- Only as leaf locks
4585 // -- for short-term locking only as muxAcquire does not perform
4586 // thread state transitions.
4587 //
4588 // Alternatives:
4589 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4590 // but with parking or spin-then-park instead of pure spinning.
4591 // * Use Taura-Oyama-Yonenzawa locks.
4592 // * It's possible to construct a 1-0 lock if we encode the lockword as
4593 // (List,LockByte). Acquire will CAS the full lockword while Release
4594 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4595 // acquiring threads use timers (ParkTimed) to detect and recover from
4596 // the stranding window. Thread/Node structures must be aligned on 256-byte
4597 // boundaries by using placement-new.
4598 // * Augment MCS with advisory back-link fields maintained with CAS().
4599 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4600 // The validity of the backlinks must be ratified before we trust the value.
4601 // If the backlinks are invalid the exiting thread must back-track through the
4602 // the forward links, which are always trustworthy.
4603 // * Add a successor indication. The LockWord is currently encoded as
4604 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4605 // to provide the usual futile-wakeup optimization.
4606 // See RTStt for details.
4607 // * Consider schedctl.sc_nopreempt to cover the critical section.
4608 //
4609
4610
4611 typedef volatile intptr_t MutexT ; // Mux Lock-word
4612 enum MuxBits { LOCKBIT = 1 } ;
4613
4614 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4615 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4616 if (w == 0) return ;
4617 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4618 return ;
4619 }
4620
4621 TEVENT (muxAcquire - Contention) ;
4622 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4623 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4624 for (;;) {
4625 int its = (os::is_MP() ? 100 : 0) + 1 ;
4626
4627 // Optional spin phase: spin-then-park strategy
4628 while (--its >= 0) {
4629 w = *Lock ;
4630 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4631 return ;
4632 }
4633 }
4634
4635 Self->reset() ;
4636 Self->OnList = intptr_t(Lock) ;
4637 // The following fence() isn't _strictly necessary as the subsequent
4638 // CAS() both serializes execution and ratifies the fetched *Lock value.
4639 OrderAccess::fence();
4640 for (;;) {
4641 w = *Lock ;
4642 if ((w & LOCKBIT) == 0) {
4643 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4644 Self->OnList = 0 ; // hygiene - allows stronger asserts
4645 return ;
4646 }
4647 continue ; // Interference -- *Lock changed -- Just retry
4648 }
4649 assert (w & LOCKBIT, "invariant") ;
4650 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4651 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4652 }
4653
4654 while (Self->OnList != 0) {
4655 Self->park() ;
4656 }
4657 }
4658 }
4659
4660 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4661 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4662 if (w == 0) return ;
4663 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4664 return ;
4665 }
4666
4667 TEVENT (muxAcquire - Contention) ;
4668 ParkEvent * ReleaseAfter = NULL ;
4669 if (ev == NULL) {
4670 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4671 }
4672 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4673 for (;;) {
4674 guarantee (ev->OnList == 0, "invariant") ;
4675 int its = (os::is_MP() ? 100 : 0) + 1 ;
4676
4677 // Optional spin phase: spin-then-park strategy
4678 while (--its >= 0) {
4679 w = *Lock ;
4680 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4681 if (ReleaseAfter != NULL) {
4682 ParkEvent::Release (ReleaseAfter) ;
4683 }
4684 return ;
4685 }
4686 }
4687
4688 ev->reset() ;
4689 ev->OnList = intptr_t(Lock) ;
4690 // The following fence() isn't _strictly necessary as the subsequent
4691 // CAS() both serializes execution and ratifies the fetched *Lock value.
4692 OrderAccess::fence();
4693 for (;;) {
4694 w = *Lock ;
4695 if ((w & LOCKBIT) == 0) {
4696 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4697 ev->OnList = 0 ;
4698 // We call ::Release while holding the outer lock, thus
4699 // artificially lengthening the critical section.
4700 // Consider deferring the ::Release() until the subsequent unlock(),
4701 // after we've dropped the outer lock.
4702 if (ReleaseAfter != NULL) {
4703 ParkEvent::Release (ReleaseAfter) ;
4704 }
4705 return ;
4706 }
4707 continue ; // Interference -- *Lock changed -- Just retry
4708 }
4709 assert (w & LOCKBIT, "invariant") ;
4710 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4711 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4712 }
4713
4714 while (ev->OnList != 0) {
4715 ev->park() ;
4716 }
4717 }
4718 }
4719
4720 // Release() must extract a successor from the list and then wake that thread.
4721 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4722 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4723 // Release() would :
4724 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4725 // (B) Extract a successor from the private list "in-hand"
4726 // (C) attempt to CAS() the residual back into *Lock over null.
4727 // If there were any newly arrived threads and the CAS() would fail.
4728 // In that case Release() would detach the RATs, re-merge the list in-hand
4729 // with the RATs and repeat as needed. Alternately, Release() might
4730 // detach and extract a successor, but then pass the residual list to the wakee.
4731 // The wakee would be responsible for reattaching and remerging before it
4732 // competed for the lock.
4733 //
4734 // Both "pop" and DMR are immune from ABA corruption -- there can be
4735 // multiple concurrent pushers, but only one popper or detacher.
4736 // This implementation pops from the head of the list. This is unfair,
4737 // but tends to provide excellent throughput as hot threads remain hot.
4738 // (We wake recently run threads first).
4739
4740 void Thread::muxRelease (volatile intptr_t * Lock) {
4741 for (;;) {
4742 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4743 assert (w & LOCKBIT, "invariant") ;
4744 if (w == LOCKBIT) return ;
4745 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4746 assert (List != NULL, "invariant") ;
4747 assert (List->OnList == intptr_t(Lock), "invariant") ;
4748 ParkEvent * nxt = List->ListNext ;
4749
4750 // The following CAS() releases the lock and pops the head element.
4751 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4752 continue ;
4753 }
4754 List->OnList = 0 ;
4755 OrderAccess::fence() ;
4756 List->unpark () ;
4757 return ;
4758 }
4759 }
4760
4761
4762 void Threads::verify() {
4763 ALL_JAVA_THREADS(p) {
4764 p->verify();
4765 }
4766 VMThread* thread = VMThread::vm_thread();
4767 if (thread != NULL) thread->verify();
4768 }