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