1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "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/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
102 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
103 #endif // INCLUDE_ALL_GCS
104 #ifdef COMPILER1
105 #include "c1/c1_Compiler.hpp"
106 #endif
107 #ifdef COMPILER2
108 #include "opto/c2compiler.hpp"
109 #include "opto/idealGraphPrinter.hpp"
110 #endif
111 #if INCLUDE_RTM_OPT
112 #include "runtime/rtmLocking.hpp"
113 #endif
114
115 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
116
117 #ifdef DTRACE_ENABLED
118
119 // Only bother with this argument setup if dtrace is available
120
121 #ifndef USDT2
122 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
123 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
124 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
125 intptr_t, intptr_t, bool);
126 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
127 intptr_t, intptr_t, bool);
128
129 #define DTRACE_THREAD_PROBE(probe, javathread) \
130 { \
131 ResourceMark rm(this); \
132 int len = 0; \
133 const char* name = (javathread)->get_thread_name(); \
134 len = strlen(name); \
135 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
136 name, len, \
137 java_lang_Thread::thread_id((javathread)->threadObj()), \
138 (javathread)->osthread()->thread_id(), \
139 java_lang_Thread::is_daemon((javathread)->threadObj())); \
140 }
141
142 #else /* USDT2 */
143
144 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
145 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
146
147 #define DTRACE_THREAD_PROBE(probe, javathread) \
148 { \
149 ResourceMark rm(this); \
150 int len = 0; \
151 const char* name = (javathread)->get_thread_name(); \
152 len = strlen(name); \
153 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
154 (char *) name, len, \
155 java_lang_Thread::thread_id((javathread)->threadObj()), \
156 (uintptr_t) (javathread)->osthread()->thread_id(), \
157 java_lang_Thread::is_daemon((javathread)->threadObj())); \
158 }
159
160 #endif /* USDT2 */
161
162 #else // ndef DTRACE_ENABLED
163
164 #define DTRACE_THREAD_PROBE(probe, javathread)
165
166 #endif // ndef DTRACE_ENABLED
167
168
169 // Class hierarchy
170 // - Thread
171 // - VMThread
172 // - WatcherThread
173 // - ConcurrentMarkSweepThread
174 // - JavaThread
175 // - CompilerThread
176
177 // ======= Thread ========
178 // Support for forcing alignment of thread objects for biased locking
179 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
180 if (UseBiasedLocking) {
181 const int alignment = markOopDesc::biased_lock_alignment;
182 size_t aligned_size = size + (alignment - sizeof(intptr_t));
183 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
184 : AllocateHeap(aligned_size, flags, CURRENT_PC,
185 AllocFailStrategy::RETURN_NULL);
186 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
187 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
188 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
189 "JavaThread alignment code overflowed allocated storage");
190 if (TraceBiasedLocking) {
191 if (aligned_addr != real_malloc_addr)
192 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
193 real_malloc_addr, aligned_addr);
194 }
195 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
196 return aligned_addr;
197 } else {
198 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
199 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
200 }
201 }
202
203 void Thread::operator delete(void* p) {
204 if (UseBiasedLocking) {
205 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
206 FreeHeap(real_malloc_addr, mtThread);
207 } else {
208 FreeHeap(p, mtThread);
209 }
210 }
211
212
213 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
214 // JavaThread
215
216
217 Thread::Thread() {
218 // stack and get_thread
219 set_stack_base(NULL);
220 set_stack_size(0);
221 set_self_raw_id(0);
222 set_lgrp_id(-1);
223
224 // allocated data structures
225 set_osthread(NULL);
226 set_resource_area(new (mtThread)ResourceArea());
227 DEBUG_ONLY(_current_resource_mark = NULL;)
228 set_handle_area(new (mtThread) HandleArea(NULL));
229 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
230 set_active_handles(NULL);
231 set_free_handle_block(NULL);
232 set_last_handle_mark(NULL);
233
234 // This initial value ==> never claimed.
235 _oops_do_parity = 0;
236
237 _metadata_on_stack_buffer = NULL;
238
239 // the handle mark links itself to last_handle_mark
240 new HandleMark(this);
241
242 // plain initialization
243 debug_only(_owned_locks = NULL;)
244 debug_only(_allow_allocation_count = 0;)
245 NOT_PRODUCT(_allow_safepoint_count = 0;)
246 NOT_PRODUCT(_skip_gcalot = false;)
247 _jvmti_env_iteration_count = 0;
248 set_allocated_bytes(0);
249 _vm_operation_started_count = 0;
250 _vm_operation_completed_count = 0;
251 _current_pending_monitor = NULL;
252 _current_pending_monitor_is_from_java = true;
253 _current_waiting_monitor = NULL;
254 _num_nested_signal = 0;
255 omFreeList = NULL ;
256 omFreeCount = 0 ;
257 omFreeProvision = 32 ;
258 omInUseList = NULL ;
259 omInUseCount = 0 ;
260
261 #ifdef ASSERT
262 _visited_for_critical_count = false;
263 #endif
264
265 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
266 _suspend_flags = 0;
267
268 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
269 _hashStateX = os::random() ;
270 _hashStateY = 842502087 ;
271 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
272 _hashStateW = 273326509 ;
273
274 _OnTrap = 0 ;
275 _schedctl = NULL ;
276 _Stalled = 0 ;
277 _TypeTag = 0x2BAD ;
278
279 // Many of the following fields are effectively final - immutable
280 // Note that nascent threads can't use the Native Monitor-Mutex
281 // construct until the _MutexEvent is initialized ...
282 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
283 // we might instead use a stack of ParkEvents that we could provision on-demand.
284 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
285 // and ::Release()
286 _ParkEvent = ParkEvent::Allocate (this) ;
287 _SleepEvent = ParkEvent::Allocate (this) ;
288 _MutexEvent = ParkEvent::Allocate (this) ;
289 _MuxEvent = ParkEvent::Allocate (this) ;
290
291 #ifdef CHECK_UNHANDLED_OOPS
292 if (CheckUnhandledOops) {
293 _unhandled_oops = new UnhandledOops(this);
294 }
295 #endif // CHECK_UNHANDLED_OOPS
296 #ifdef ASSERT
297 if (UseBiasedLocking) {
298 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
299 assert(this == _real_malloc_address ||
300 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
301 "bug in forced alignment of thread objects");
302 }
303 #endif /* ASSERT */
304 }
305
306 void Thread::initialize_thread_local_storage() {
307 // Note: Make sure this method only calls
308 // non-blocking operations. Otherwise, it might not work
309 // with the thread-startup/safepoint interaction.
310
311 // During Java thread startup, safepoint code should allow this
312 // method to complete because it may need to allocate memory to
313 // store information for the new thread.
314
315 // initialize structure dependent on thread local storage
316 ThreadLocalStorage::set_thread(this);
317 }
318
319 void Thread::record_stack_base_and_size() {
320 set_stack_base(os::current_stack_base());
321 set_stack_size(os::current_stack_size());
322 if (is_Java_thread()) {
323 ((JavaThread*) this)->set_stack_overflow_limit();
324 }
325 // CR 7190089: on Solaris, primordial thread's stack is adjusted
326 // in initialize_thread(). Without the adjustment, stack size is
327 // incorrect if stack is set to unlimited (ulimit -s unlimited).
328 // So far, only Solaris has real implementation of initialize_thread().
329 //
330 // set up any platform-specific state.
331 os::initialize_thread(this);
332
333 #if INCLUDE_NMT
334 // record thread's native stack, stack grows downward
335 address stack_low_addr = stack_base() - stack_size();
336 MemTracker::record_thread_stack(stack_low_addr, stack_size());
337 #endif // INCLUDE_NMT
338 }
339
340
341 Thread::~Thread() {
342 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
343 ObjectSynchronizer::omFlush (this) ;
344
345 EVENT_THREAD_DESTRUCT(this);
346
347 // stack_base can be NULL if the thread is never started or exited before
348 // record_stack_base_and_size called. Although, we would like to ensure
349 // that all started threads do call record_stack_base_and_size(), there is
350 // not proper way to enforce that.
351 #if INCLUDE_NMT
352 if (_stack_base != NULL) {
353 address low_stack_addr = stack_base() - stack_size();
354 MemTracker::release_thread_stack(low_stack_addr, stack_size());
355 #ifdef ASSERT
356 set_stack_base(NULL);
357 #endif
358 }
359 #endif // INCLUDE_NMT
360
361 // deallocate data structures
362 delete resource_area();
363 // since the handle marks are using the handle area, we have to deallocated the root
364 // handle mark before deallocating the thread's handle area,
365 assert(last_handle_mark() != NULL, "check we have an element");
366 delete last_handle_mark();
367 assert(last_handle_mark() == NULL, "check we have reached the end");
368
369 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
370 // We NULL out the fields for good hygiene.
371 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
372 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
373 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
374 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
375
376 delete handle_area();
377 delete metadata_handles();
378
379 // osthread() can be NULL, if creation of thread failed.
380 if (osthread() != NULL) os::free_thread(osthread());
381
382 delete _SR_lock;
383
384 // clear thread local storage if the Thread is deleting itself
385 if (this == Thread::current()) {
386 ThreadLocalStorage::set_thread(NULL);
387 } else {
388 // In the case where we're not the current thread, invalidate all the
389 // caches in case some code tries to get the current thread or the
390 // thread that was destroyed, and gets stale information.
391 ThreadLocalStorage::invalidate_all();
392 }
393 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
394 }
395
396 // NOTE: dummy function for assertion purpose.
397 void Thread::run() {
398 ShouldNotReachHere();
399 }
400
401 #ifdef ASSERT
402 // Private method to check for dangling thread pointer
403 void check_for_dangling_thread_pointer(Thread *thread) {
404 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
405 "possibility of dangling Thread pointer");
406 }
407 #endif
408
409
410 #ifndef PRODUCT
411 // Tracing method for basic thread operations
412 void Thread::trace(const char* msg, const Thread* const thread) {
413 if (!TraceThreadEvents) return;
414 ResourceMark rm;
415 ThreadCritical tc;
416 const char *name = "non-Java thread";
417 int prio = -1;
418 if (thread->is_Java_thread()
419 && !thread->is_Compiler_thread()) {
420 // The Threads_lock must be held to get information about
421 // this thread but may not be in some situations when
422 // tracing thread events.
423 bool release_Threads_lock = false;
424 if (!Threads_lock->owned_by_self()) {
425 Threads_lock->lock();
426 release_Threads_lock = true;
427 }
428 JavaThread* jt = (JavaThread *)thread;
429 name = (char *)jt->get_thread_name();
430 oop thread_oop = jt->threadObj();
431 if (thread_oop != NULL) {
432 prio = java_lang_Thread::priority(thread_oop);
433 }
434 if (release_Threads_lock) {
435 Threads_lock->unlock();
436 }
437 }
438 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
439 }
440 #endif
441
442
443 ThreadPriority Thread::get_priority(const Thread* const thread) {
444 trace("get priority", thread);
445 ThreadPriority priority;
446 // Can return an error!
447 (void)os::get_priority(thread, priority);
448 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
449 return priority;
450 }
451
452 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
453 trace("set priority", thread);
454 debug_only(check_for_dangling_thread_pointer(thread);)
455 // Can return an error!
456 (void)os::set_priority(thread, priority);
457 }
458
459
460 void Thread::start(Thread* thread) {
461 trace("start", thread);
462 // Start is different from resume in that its safety is guaranteed by context or
463 // being called from a Java method synchronized on the Thread object.
464 if (!DisableStartThread) {
465 if (thread->is_Java_thread()) {
466 // Initialize the thread state to RUNNABLE before starting this thread.
467 // Can not set it after the thread started because we do not know the
468 // exact thread state at that time. It could be in MONITOR_WAIT or
469 // in SLEEPING or some other state.
470 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
471 java_lang_Thread::RUNNABLE);
472 }
473 os::start_thread(thread);
474 }
475 }
476
477 // Enqueue a VM_Operation to do the job for us - sometime later
478 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
479 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
480 VMThread::execute(vm_stop);
481 }
482
483
484 //
485 // Check if an external suspend request has completed (or has been
486 // cancelled). Returns true if the thread is externally suspended and
487 // false otherwise.
488 //
489 // The bits parameter returns information about the code path through
490 // the routine. Useful for debugging:
491 //
492 // set in is_ext_suspend_completed():
493 // 0x00000001 - routine was entered
494 // 0x00000010 - routine return false at end
495 // 0x00000100 - thread exited (return false)
496 // 0x00000200 - suspend request cancelled (return false)
497 // 0x00000400 - thread suspended (return true)
498 // 0x00001000 - thread is in a suspend equivalent state (return true)
499 // 0x00002000 - thread is native and walkable (return true)
500 // 0x00004000 - thread is native_trans and walkable (needed retry)
501 //
502 // set in wait_for_ext_suspend_completion():
503 // 0x00010000 - routine was entered
504 // 0x00020000 - suspend request cancelled before loop (return false)
505 // 0x00040000 - thread suspended before loop (return true)
506 // 0x00080000 - suspend request cancelled in loop (return false)
507 // 0x00100000 - thread suspended in loop (return true)
508 // 0x00200000 - suspend not completed during retry loop (return false)
509 //
510
511 // Helper class for tracing suspend wait debug bits.
512 //
513 // 0x00000100 indicates that the target thread exited before it could
514 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
515 // 0x00080000 each indicate a cancelled suspend request so they don't
516 // count as wait failures either.
517 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
518
519 class TraceSuspendDebugBits : public StackObj {
520 private:
521 JavaThread * jt;
522 bool is_wait;
523 bool called_by_wait; // meaningful when !is_wait
524 uint32_t * bits;
525
526 public:
527 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
528 uint32_t *_bits) {
529 jt = _jt;
530 is_wait = _is_wait;
531 called_by_wait = _called_by_wait;
532 bits = _bits;
533 }
534
535 ~TraceSuspendDebugBits() {
536 if (!is_wait) {
537 #if 1
538 // By default, don't trace bits for is_ext_suspend_completed() calls.
539 // That trace is very chatty.
540 return;
541 #else
542 if (!called_by_wait) {
543 // If tracing for is_ext_suspend_completed() is enabled, then only
544 // trace calls to it from wait_for_ext_suspend_completion()
545 return;
546 }
547 #endif
548 }
549
550 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
551 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
552 MutexLocker ml(Threads_lock); // needed for get_thread_name()
553 ResourceMark rm;
554
555 tty->print_cr(
556 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
557 jt->get_thread_name(), *bits);
558
559 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
560 }
561 }
562 }
563 };
564 #undef DEBUG_FALSE_BITS
565
566
567 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
568 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
569
570 bool did_trans_retry = false; // only do thread_in_native_trans retry once
571 bool do_trans_retry; // flag to force the retry
572
573 *bits |= 0x00000001;
574
575 do {
576 do_trans_retry = false;
577
578 if (is_exiting()) {
579 // Thread is in the process of exiting. This is always checked
580 // first to reduce the risk of dereferencing a freed JavaThread.
581 *bits |= 0x00000100;
582 return false;
583 }
584
585 if (!is_external_suspend()) {
586 // Suspend request is cancelled. This is always checked before
587 // is_ext_suspended() to reduce the risk of a rogue resume
588 // confusing the thread that made the suspend request.
589 *bits |= 0x00000200;
590 return false;
591 }
592
593 if (is_ext_suspended()) {
594 // thread is suspended
595 *bits |= 0x00000400;
596 return true;
597 }
598
599 // Now that we no longer do hard suspends of threads running
600 // native code, the target thread can be changing thread state
601 // while we are in this routine:
602 //
603 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
604 //
605 // We save a copy of the thread state as observed at this moment
606 // and make our decision about suspend completeness based on the
607 // copy. This closes the race where the thread state is seen as
608 // _thread_in_native_trans in the if-thread_blocked check, but is
609 // seen as _thread_blocked in if-thread_in_native_trans check.
610 JavaThreadState save_state = thread_state();
611
612 if (save_state == _thread_blocked && is_suspend_equivalent()) {
613 // If the thread's state is _thread_blocked and this blocking
614 // condition is known to be equivalent to a suspend, then we can
615 // consider the thread to be externally suspended. This means that
616 // the code that sets _thread_blocked has been modified to do
617 // self-suspension if the blocking condition releases. We also
618 // used to check for CONDVAR_WAIT here, but that is now covered by
619 // the _thread_blocked with self-suspension check.
620 //
621 // Return true since we wouldn't be here unless there was still an
622 // external suspend request.
623 *bits |= 0x00001000;
624 return true;
625 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
626 // Threads running native code will self-suspend on native==>VM/Java
627 // transitions. If its stack is walkable (should always be the case
628 // unless this function is called before the actual java_suspend()
629 // call), then the wait is done.
630 *bits |= 0x00002000;
631 return true;
632 } else if (!called_by_wait && !did_trans_retry &&
633 save_state == _thread_in_native_trans &&
634 frame_anchor()->walkable()) {
635 // The thread is transitioning from thread_in_native to another
636 // thread state. check_safepoint_and_suspend_for_native_trans()
637 // will force the thread to self-suspend. If it hasn't gotten
638 // there yet we may have caught the thread in-between the native
639 // code check above and the self-suspend. Lucky us. If we were
640 // called by wait_for_ext_suspend_completion(), then it
641 // will be doing the retries so we don't have to.
642 //
643 // Since we use the saved thread state in the if-statement above,
644 // there is a chance that the thread has already transitioned to
645 // _thread_blocked by the time we get here. In that case, we will
646 // make a single unnecessary pass through the logic below. This
647 // doesn't hurt anything since we still do the trans retry.
648
649 *bits |= 0x00004000;
650
651 // Once the thread leaves thread_in_native_trans for another
652 // thread state, we break out of this retry loop. We shouldn't
653 // need this flag to prevent us from getting back here, but
654 // sometimes paranoia is good.
655 did_trans_retry = true;
656
657 // We wait for the thread to transition to a more usable state.
658 for (int i = 1; i <= SuspendRetryCount; i++) {
659 // We used to do an "os::yield_all(i)" call here with the intention
660 // that yielding would increase on each retry. However, the parameter
661 // is ignored on Linux which means the yield didn't scale up. Waiting
662 // on the SR_lock below provides a much more predictable scale up for
663 // the delay. It also provides a simple/direct point to check for any
664 // safepoint requests from the VMThread
665
666 // temporarily drops SR_lock while doing wait with safepoint check
667 // (if we're a JavaThread - the WatcherThread can also call this)
668 // and increase delay with each retry
669 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
670
671 // check the actual thread state instead of what we saved above
672 if (thread_state() != _thread_in_native_trans) {
673 // the thread has transitioned to another thread state so
674 // try all the checks (except this one) one more time.
675 do_trans_retry = true;
676 break;
677 }
678 } // end retry loop
679
680
681 }
682 } while (do_trans_retry);
683
684 *bits |= 0x00000010;
685 return false;
686 }
687
688 //
689 // Wait for an external suspend request to complete (or be cancelled).
690 // Returns true if the thread is externally suspended and false otherwise.
691 //
692 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
693 uint32_t *bits) {
694 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
695 false /* !called_by_wait */, bits);
696
697 // local flag copies to minimize SR_lock hold time
698 bool is_suspended;
699 bool pending;
700 uint32_t reset_bits;
701
702 // set a marker so is_ext_suspend_completed() knows we are the caller
703 *bits |= 0x00010000;
704
705 // We use reset_bits to reinitialize the bits value at the top of
706 // each retry loop. This allows the caller to make use of any
707 // unused bits for their own marking purposes.
708 reset_bits = *bits;
709
710 {
711 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
712 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
713 delay, bits);
714 pending = is_external_suspend();
715 }
716 // must release SR_lock to allow suspension to complete
717
718 if (!pending) {
719 // A cancelled suspend request is the only false return from
720 // is_ext_suspend_completed() that keeps us from entering the
721 // retry loop.
722 *bits |= 0x00020000;
723 return false;
724 }
725
726 if (is_suspended) {
727 *bits |= 0x00040000;
728 return true;
729 }
730
731 for (int i = 1; i <= retries; i++) {
732 *bits = reset_bits; // reinit to only track last retry
733
734 // We used to do an "os::yield_all(i)" call here with the intention
735 // that yielding would increase on each retry. However, the parameter
736 // is ignored on Linux which means the yield didn't scale up. Waiting
737 // on the SR_lock below provides a much more predictable scale up for
738 // the delay. It also provides a simple/direct point to check for any
739 // safepoint requests from the VMThread
740
741 {
742 MutexLocker ml(SR_lock());
743 // wait with safepoint check (if we're a JavaThread - the WatcherThread
744 // can also call this) and increase delay with each retry
745 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
746
747 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
748 delay, bits);
749
750 // It is possible for the external suspend request to be cancelled
751 // (by a resume) before the actual suspend operation is completed.
752 // Refresh our local copy to see if we still need to wait.
753 pending = is_external_suspend();
754 }
755
756 if (!pending) {
757 // A cancelled suspend request is the only false return from
758 // is_ext_suspend_completed() that keeps us from staying in the
759 // retry loop.
760 *bits |= 0x00080000;
761 return false;
762 }
763
764 if (is_suspended) {
765 *bits |= 0x00100000;
766 return true;
767 }
768 } // end retry loop
769
770 // thread did not suspend after all our retries
771 *bits |= 0x00200000;
772 return false;
773 }
774
775 #ifndef PRODUCT
776 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
777
778 // This should not need to be atomic as the only way for simultaneous
779 // updates is via interrupts. Even then this should be rare or non-existant
780 // and we don't care that much anyway.
781
782 int index = _jmp_ring_index;
783 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
784 _jmp_ring[index]._target = (intptr_t) target;
785 _jmp_ring[index]._instruction = (intptr_t) instr;
786 _jmp_ring[index]._file = file;
787 _jmp_ring[index]._line = line;
788 }
789 #endif /* PRODUCT */
790
791 // Called by flat profiler
792 // Callers have already called wait_for_ext_suspend_completion
793 // The assertion for that is currently too complex to put here:
794 bool JavaThread::profile_last_Java_frame(frame* _fr) {
795 bool gotframe = false;
796 // self suspension saves needed state.
797 if (has_last_Java_frame() && _anchor.walkable()) {
798 *_fr = pd_last_frame();
799 gotframe = true;
800 }
801 return gotframe;
802 }
803
804 void Thread::interrupt(Thread* thread) {
805 trace("interrupt", thread);
806 debug_only(check_for_dangling_thread_pointer(thread);)
807 os::interrupt(thread);
808 }
809
810 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
811 trace("is_interrupted", thread);
812 debug_only(check_for_dangling_thread_pointer(thread);)
813 // Note: If clear_interrupted==false, this simply fetches and
814 // returns the value of the field osthread()->interrupted().
815 return os::is_interrupted(thread, clear_interrupted);
816 }
817
818
819 // GC Support
820 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
821 jint thread_parity = _oops_do_parity;
822 if (thread_parity != strong_roots_parity) {
823 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
824 if (res == thread_parity) {
825 return true;
826 } else {
827 guarantee(res == strong_roots_parity, "Or else what?");
828 assert(SharedHeap::heap()->workers()->active_workers() > 0,
829 "Should only fail when parallel.");
830 return false;
831 }
832 }
833 assert(SharedHeap::heap()->workers()->active_workers() > 0,
834 "Should only fail when parallel.");
835 return false;
836 }
837
838 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
839 active_handles()->oops_do(f);
840 // Do oop for ThreadShadow
841 f->do_oop((oop*)&_pending_exception);
842 handle_area()->oops_do(f);
843 }
844
845 void Thread::nmethods_do(CodeBlobClosure* cf) {
846 // no nmethods in a generic thread...
847 }
848
849 void Thread::metadata_do(void f(Metadata*)) {
850 if (metadata_handles() != NULL) {
851 for (int i = 0; i< metadata_handles()->length(); i++) {
852 f(metadata_handles()->at(i));
853 }
854 }
855 }
856
857 void Thread::print_on(outputStream* st) const {
858 // get_priority assumes osthread initialized
859 if (osthread() != NULL) {
860 int os_prio;
861 if (os::get_native_priority(this, &os_prio) == OS_OK) {
862 st->print("os_prio=%d ", os_prio);
863 }
864 st->print("tid=" INTPTR_FORMAT " ", this);
865 ext().print_on(st);
866 osthread()->print_on(st);
867 }
868 debug_only(if (WizardMode) print_owned_locks_on(st);)
869 }
870
871 // Thread::print_on_error() is called by fatal error handler. Don't use
872 // any lock or allocate memory.
873 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
874 if (is_VM_thread()) st->print("VMThread");
875 else if (is_Compiler_thread()) st->print("CompilerThread");
876 else if (is_Java_thread()) st->print("JavaThread");
877 else if (is_GC_task_thread()) st->print("GCTaskThread");
878 else if (is_Watcher_thread()) st->print("WatcherThread");
879 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
880 else st->print("Thread");
881
882 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
883 _stack_base - _stack_size, _stack_base);
884
885 if (osthread()) {
886 st->print(" [id=%d]", osthread()->thread_id());
887 }
888 }
889
890 #ifdef ASSERT
891 void Thread::print_owned_locks_on(outputStream* st) const {
892 Monitor *cur = _owned_locks;
893 if (cur == NULL) {
894 st->print(" (no locks) ");
895 } else {
896 st->print_cr(" Locks owned:");
897 while(cur) {
898 cur->print_on(st);
899 cur = cur->next();
900 }
901 }
902 }
903
904 static int ref_use_count = 0;
905
906 bool Thread::owns_locks_but_compiled_lock() const {
907 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
908 if (cur != Compile_lock) return true;
909 }
910 return false;
911 }
912
913
914 #endif
915
916 #ifndef PRODUCT
917
918 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
919 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
920 // no threads which allow_vm_block's are held
921 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
922 // Check if current thread is allowed to block at a safepoint
923 if (!(_allow_safepoint_count == 0))
924 fatal("Possible safepoint reached by thread that does not allow it");
925 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
926 fatal("LEAF method calling lock?");
927 }
928
929 #ifdef ASSERT
930 if (potential_vm_operation && is_Java_thread()
931 && !Universe::is_bootstrapping()) {
932 // Make sure we do not hold any locks that the VM thread also uses.
933 // This could potentially lead to deadlocks
934 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
935 // Threads_lock is special, since the safepoint synchronization will not start before this is
936 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
937 // since it is used to transfer control between JavaThreads and the VMThread
938 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
939 if ( (cur->allow_vm_block() &&
940 cur != Threads_lock &&
941 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
942 cur != VMOperationRequest_lock &&
943 cur != VMOperationQueue_lock) ||
944 cur->rank() == Mutex::special) {
945 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
946 }
947 }
948 }
949
950 if (GCALotAtAllSafepoints) {
951 // We could enter a safepoint here and thus have a gc
952 InterfaceSupport::check_gc_alot();
953 }
954 #endif
955 }
956 #endif
957
958 bool Thread::is_in_stack(address adr) const {
959 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
960 address end = os::current_stack_pointer();
961 // Allow non Java threads to call this without stack_base
962 if (_stack_base == NULL) return true;
963 if (stack_base() >= adr && adr >= end) return true;
964
965 return false;
966 }
967
968
969 bool Thread::is_in_usable_stack(address adr) const {
970 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
971 size_t usable_stack_size = _stack_size - stack_guard_size;
972
973 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
974 }
975
976
977 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
978 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
979 // used for compilation in the future. If that change is made, the need for these methods
980 // should be revisited, and they should be removed if possible.
981
982 bool Thread::is_lock_owned(address adr) const {
983 return on_local_stack(adr);
984 }
985
986 bool Thread::set_as_starting_thread() {
987 // NOTE: this must be called inside the main thread.
988 return os::create_main_thread((JavaThread*)this);
989 }
990
991 // Helper to initialize_class for callers that need the klass result
992 static Klass *initialize_class_and_return(Symbol* class_name, TRAPS) {
993 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK_NULL);
994 InstanceKlass::cast(klass)->initialize(CHECK_NULL);
995 return klass;
996 }
997
998 static void initialize_class(Symbol* class_name, TRAPS) {
999 (void)initialize_class_and_return(class_name, CHECK);
1000 }
1001
1002
1003 // Creates the initial ThreadGroup
1004 static Handle create_initial_thread_group(TRAPS) {
1005 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1006 instanceKlassHandle klass (THREAD, k);
1007
1008 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1009 {
1010 JavaValue result(T_VOID);
1011 JavaCalls::call_special(&result,
1012 system_instance,
1013 klass,
1014 vmSymbols::object_initializer_name(),
1015 vmSymbols::void_method_signature(),
1016 CHECK_NH);
1017 }
1018 Universe::set_system_thread_group(system_instance());
1019
1020 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1021 {
1022 JavaValue result(T_VOID);
1023 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1024 JavaCalls::call_special(&result,
1025 main_instance,
1026 klass,
1027 vmSymbols::object_initializer_name(),
1028 vmSymbols::threadgroup_string_void_signature(),
1029 system_instance,
1030 string,
1031 CHECK_NH);
1032 }
1033 return main_instance;
1034 }
1035
1036 // Creates the initial Thread
1037 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1038 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1039 instanceKlassHandle klass (THREAD, k);
1040 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1041
1042 java_lang_Thread::set_thread(thread_oop(), thread);
1043 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1044 thread->set_threadObj(thread_oop());
1045
1046 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1047
1048 JavaValue result(T_VOID);
1049 JavaCalls::call_special(&result, thread_oop,
1050 klass,
1051 vmSymbols::object_initializer_name(),
1052 vmSymbols::threadgroup_string_void_signature(),
1053 thread_group,
1054 string,
1055 CHECK_NULL);
1056 return thread_oop();
1057 }
1058
1059 static void call_initializeSystemClass(TRAPS) {
1060 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1061 instanceKlassHandle klass (THREAD, k);
1062
1063 JavaValue result(T_VOID);
1064 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1065 vmSymbols::void_method_signature(), CHECK);
1066 }
1067
1068 char java_runtime_name[128] = "";
1069 char java_runtime_version[128] = "";
1070
1071 // extract the JRE name from sun.misc.Version.java_runtime_name
1072 static const char* get_java_runtime_name(TRAPS) {
1073 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1074 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1075 fieldDescriptor fd;
1076 bool found = k != NULL &&
1077 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1078 vmSymbols::string_signature(), &fd);
1079 if (found) {
1080 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1081 if (name_oop == NULL)
1082 return NULL;
1083 const char* name = java_lang_String::as_utf8_string(name_oop,
1084 java_runtime_name,
1085 sizeof(java_runtime_name));
1086 return name;
1087 } else {
1088 return NULL;
1089 }
1090 }
1091
1092 // extract the JRE version from sun.misc.Version.java_runtime_version
1093 static const char* get_java_runtime_version(TRAPS) {
1094 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1095 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1096 fieldDescriptor fd;
1097 bool found = k != NULL &&
1098 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1099 vmSymbols::string_signature(), &fd);
1100 if (found) {
1101 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1102 if (name_oop == NULL)
1103 return NULL;
1104 const char* name = java_lang_String::as_utf8_string(name_oop,
1105 java_runtime_version,
1106 sizeof(java_runtime_version));
1107 return name;
1108 } else {
1109 return NULL;
1110 }
1111 }
1112
1113 // General purpose hook into Java code, run once when the VM is initialized.
1114 // The Java library method itself may be changed independently from the VM.
1115 static void call_postVMInitHook(TRAPS) {
1116 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1117 instanceKlassHandle klass (THREAD, k);
1118 if (klass.not_null()) {
1119 JavaValue result(T_VOID);
1120 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1121 vmSymbols::void_method_signature(),
1122 CHECK);
1123 }
1124 }
1125
1126 static void reset_vm_info_property(TRAPS) {
1127 // the vm info string
1128 ResourceMark rm(THREAD);
1129 const char *vm_info = VM_Version::vm_info_string();
1130
1131 // java.lang.System class
1132 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1133 instanceKlassHandle klass (THREAD, k);
1134
1135 // setProperty arguments
1136 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1137 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1138
1139 // return value
1140 JavaValue r(T_OBJECT);
1141
1142 // public static String setProperty(String key, String value);
1143 JavaCalls::call_static(&r,
1144 klass,
1145 vmSymbols::setProperty_name(),
1146 vmSymbols::string_string_string_signature(),
1147 key_str,
1148 value_str,
1149 CHECK);
1150 }
1151
1152
1153 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1154 assert(thread_group.not_null(), "thread group should be specified");
1155 assert(threadObj() == NULL, "should only create Java thread object once");
1156
1157 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1158 instanceKlassHandle klass (THREAD, k);
1159 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1160
1161 java_lang_Thread::set_thread(thread_oop(), this);
1162 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1163 set_threadObj(thread_oop());
1164
1165 JavaValue result(T_VOID);
1166 if (thread_name != NULL) {
1167 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1168 // Thread gets assigned specified name and null target
1169 JavaCalls::call_special(&result,
1170 thread_oop,
1171 klass,
1172 vmSymbols::object_initializer_name(),
1173 vmSymbols::threadgroup_string_void_signature(),
1174 thread_group, // Argument 1
1175 name, // Argument 2
1176 THREAD);
1177 } else {
1178 // Thread gets assigned name "Thread-nnn" and null target
1179 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1180 JavaCalls::call_special(&result,
1181 thread_oop,
1182 klass,
1183 vmSymbols::object_initializer_name(),
1184 vmSymbols::threadgroup_runnable_void_signature(),
1185 thread_group, // Argument 1
1186 Handle(), // Argument 2
1187 THREAD);
1188 }
1189
1190
1191 if (daemon) {
1192 java_lang_Thread::set_daemon(thread_oop());
1193 }
1194
1195 if (HAS_PENDING_EXCEPTION) {
1196 return;
1197 }
1198
1199 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1200 Handle threadObj(this, this->threadObj());
1201
1202 JavaCalls::call_special(&result,
1203 thread_group,
1204 group,
1205 vmSymbols::add_method_name(),
1206 vmSymbols::thread_void_signature(),
1207 threadObj, // Arg 1
1208 THREAD);
1209
1210
1211 }
1212
1213 // NamedThread -- non-JavaThread subclasses with multiple
1214 // uniquely named instances should derive from this.
1215 NamedThread::NamedThread() : Thread() {
1216 _name = NULL;
1217 _processed_thread = NULL;
1218 }
1219
1220 NamedThread::~NamedThread() {
1221 if (_name != NULL) {
1222 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1223 _name = NULL;
1224 }
1225 }
1226
1227 void NamedThread::set_name(const char* format, ...) {
1228 guarantee(_name == NULL, "Only get to set name once.");
1229 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1230 guarantee(_name != NULL, "alloc failure");
1231 va_list ap;
1232 va_start(ap, format);
1233 jio_vsnprintf(_name, max_name_len, format, ap);
1234 va_end(ap);
1235 }
1236
1237 // ======= WatcherThread ========
1238
1239 // The watcher thread exists to simulate timer interrupts. It should
1240 // be replaced by an abstraction over whatever native support for
1241 // timer interrupts exists on the platform.
1242
1243 WatcherThread* WatcherThread::_watcher_thread = NULL;
1244 bool WatcherThread::_startable = false;
1245 volatile bool WatcherThread::_should_terminate = false;
1246
1247 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1248 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1249 if (os::create_thread(this, os::watcher_thread)) {
1250 _watcher_thread = this;
1251
1252 // Set the watcher thread to the highest OS priority which should not be
1253 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1254 // is created. The only normal thread using this priority is the reference
1255 // handler thread, which runs for very short intervals only.
1256 // If the VMThread's priority is not lower than the WatcherThread profiling
1257 // will be inaccurate.
1258 os::set_priority(this, MaxPriority);
1259 if (!DisableStartThread) {
1260 os::start_thread(this);
1261 }
1262 }
1263 }
1264
1265 int WatcherThread::sleep() const {
1266 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1267
1268 // remaining will be zero if there are no tasks,
1269 // causing the WatcherThread to sleep until a task is
1270 // enrolled
1271 int remaining = PeriodicTask::time_to_wait();
1272 int time_slept = 0;
1273
1274 // we expect this to timeout - we only ever get unparked when
1275 // we should terminate or when a new task has been enrolled
1276 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1277
1278 jlong time_before_loop = os::javaTimeNanos();
1279
1280 for (;;) {
1281 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1282 jlong now = os::javaTimeNanos();
1283
1284 if (remaining == 0) {
1285 // if we didn't have any tasks we could have waited for a long time
1286 // consider the time_slept zero and reset time_before_loop
1287 time_slept = 0;
1288 time_before_loop = now;
1289 } else {
1290 // need to recalulate since we might have new tasks in _tasks
1291 time_slept = (int) ((now - time_before_loop) / 1000000);
1292 }
1293
1294 // Change to task list or spurious wakeup of some kind
1295 if (timedout || _should_terminate) {
1296 break;
1297 }
1298
1299 remaining = PeriodicTask::time_to_wait();
1300 if (remaining == 0) {
1301 // Last task was just disenrolled so loop around and wait until
1302 // another task gets enrolled
1303 continue;
1304 }
1305
1306 remaining -= time_slept;
1307 if (remaining <= 0)
1308 break;
1309 }
1310
1311 return time_slept;
1312 }
1313
1314 void WatcherThread::run() {
1315 assert(this == watcher_thread(), "just checking");
1316
1317 this->record_stack_base_and_size();
1318 this->initialize_thread_local_storage();
1319 this->set_active_handles(JNIHandleBlock::allocate_block());
1320 while(!_should_terminate) {
1321 assert(watcher_thread() == Thread::current(), "thread consistency check");
1322 assert(watcher_thread() == this, "thread consistency check");
1323
1324 // Calculate how long it'll be until the next PeriodicTask work
1325 // should be done, and sleep that amount of time.
1326 int time_waited = sleep();
1327
1328 if (is_error_reported()) {
1329 // A fatal error has happened, the error handler(VMError::report_and_die)
1330 // should abort JVM after creating an error log file. However in some
1331 // rare cases, the error handler itself might deadlock. Here we try to
1332 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1333 //
1334 // This code is in WatcherThread because WatcherThread wakes up
1335 // periodically so the fatal error handler doesn't need to do anything;
1336 // also because the WatcherThread is less likely to crash than other
1337 // threads.
1338
1339 for (;;) {
1340 if (!ShowMessageBoxOnError
1341 && (OnError == NULL || OnError[0] == '\0')
1342 && Arguments::abort_hook() == NULL) {
1343 os::sleep(this, 2 * 60 * 1000, false);
1344 fdStream err(defaultStream::output_fd());
1345 err.print_raw_cr("# [ timer expired, abort... ]");
1346 // skip atexit/vm_exit/vm_abort hooks
1347 os::die();
1348 }
1349
1350 // Wake up 5 seconds later, the fatal handler may reset OnError or
1351 // ShowMessageBoxOnError when it is ready to abort.
1352 os::sleep(this, 5 * 1000, false);
1353 }
1354 }
1355
1356 PeriodicTask::real_time_tick(time_waited);
1357 }
1358
1359 // Signal that it is terminated
1360 {
1361 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1362 _watcher_thread = NULL;
1363 Terminator_lock->notify();
1364 }
1365
1366 // Thread destructor usually does this..
1367 ThreadLocalStorage::set_thread(NULL);
1368 }
1369
1370 void WatcherThread::start() {
1371 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1372
1373 if (watcher_thread() == NULL && _startable) {
1374 _should_terminate = false;
1375 // Create the single instance of WatcherThread
1376 new WatcherThread();
1377 }
1378 }
1379
1380 void WatcherThread::make_startable() {
1381 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1382 _startable = true;
1383 }
1384
1385 void WatcherThread::stop() {
1386 {
1387 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1388 _should_terminate = true;
1389 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1390
1391 WatcherThread* watcher = watcher_thread();
1392 if (watcher != NULL)
1393 watcher->unpark();
1394 }
1395
1396 // it is ok to take late safepoints here, if needed
1397 MutexLocker mu(Terminator_lock);
1398
1399 while(watcher_thread() != NULL) {
1400 // This wait should make safepoint checks, wait without a timeout,
1401 // and wait as a suspend-equivalent condition.
1402 //
1403 // Note: If the FlatProfiler is running, then this thread is waiting
1404 // for the WatcherThread to terminate and the WatcherThread, via the
1405 // FlatProfiler task, is waiting for the external suspend request on
1406 // this thread to complete. wait_for_ext_suspend_completion() will
1407 // eventually timeout, but that takes time. Making this wait a
1408 // suspend-equivalent condition solves that timeout problem.
1409 //
1410 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1411 Mutex::_as_suspend_equivalent_flag);
1412 }
1413 }
1414
1415 void WatcherThread::unpark() {
1416 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1417 PeriodicTask_lock->notify();
1418 }
1419
1420 void WatcherThread::print_on(outputStream* st) const {
1421 st->print("\"%s\" ", name());
1422 Thread::print_on(st);
1423 st->cr();
1424 }
1425
1426 // ======= JavaThread ========
1427
1428 // A JavaThread is a normal Java thread
1429
1430 void JavaThread::initialize() {
1431 // Initialize fields
1432
1433 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1434 set_claimed_par_id(UINT_MAX);
1435
1436 set_saved_exception_pc(NULL);
1437 set_threadObj(NULL);
1438 _anchor.clear();
1439 set_entry_point(NULL);
1440 set_jni_functions(jni_functions());
1441 set_callee_target(NULL);
1442 set_vm_result(NULL);
1443 set_vm_result_2(NULL);
1444 set_vframe_array_head(NULL);
1445 set_vframe_array_last(NULL);
1446 set_deferred_locals(NULL);
1447 set_deopt_mark(NULL);
1448 set_deopt_nmethod(NULL);
1449 clear_must_deopt_id();
1450 set_monitor_chunks(NULL);
1451 set_next(NULL);
1452 set_thread_state(_thread_new);
1453 _terminated = _not_terminated;
1454 _privileged_stack_top = NULL;
1455 _array_for_gc = NULL;
1456 _suspend_equivalent = false;
1457 _in_deopt_handler = 0;
1458 _doing_unsafe_access = false;
1459 _stack_guard_state = stack_guard_unused;
1460 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1461 _exception_pc = 0;
1462 _exception_handler_pc = 0;
1463 _is_method_handle_return = 0;
1464 _jvmti_thread_state= NULL;
1465 _should_post_on_exceptions_flag = JNI_FALSE;
1466 _jvmti_get_loaded_classes_closure = NULL;
1467 _interp_only_mode = 0;
1468 _special_runtime_exit_condition = _no_async_condition;
1469 _pending_async_exception = NULL;
1470 _thread_stat = NULL;
1471 _thread_stat = new ThreadStatistics();
1472 _blocked_on_compilation = false;
1473 _jni_active_critical = 0;
1474 _pending_jni_exception_check_fn = NULL;
1475 _do_not_unlock_if_synchronized = false;
1476 _cached_monitor_info = NULL;
1477 _parker = Parker::Allocate(this) ;
1478
1479 #ifndef PRODUCT
1480 _jmp_ring_index = 0;
1481 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1482 record_jump(NULL, NULL, NULL, 0);
1483 }
1484 #endif /* PRODUCT */
1485
1486 set_thread_profiler(NULL);
1487 if (FlatProfiler::is_active()) {
1488 // This is where we would decide to either give each thread it's own profiler
1489 // or use one global one from FlatProfiler,
1490 // or up to some count of the number of profiled threads, etc.
1491 ThreadProfiler* pp = new ThreadProfiler();
1492 pp->engage();
1493 set_thread_profiler(pp);
1494 }
1495
1496 // Setup safepoint state info for this thread
1497 ThreadSafepointState::create(this);
1498
1499 debug_only(_java_call_counter = 0);
1500
1501 // JVMTI PopFrame support
1502 _popframe_condition = popframe_inactive;
1503 _popframe_preserved_args = NULL;
1504 _popframe_preserved_args_size = 0;
1505 _frames_to_pop_failed_realloc = 0;
1506
1507 pd_initialize();
1508 }
1509
1510 #if INCLUDE_ALL_GCS
1511 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1512 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1513 #endif // INCLUDE_ALL_GCS
1514
1515 JavaThread::JavaThread(bool is_attaching_via_jni) :
1516 Thread()
1517 #if INCLUDE_ALL_GCS
1518 , _satb_mark_queue(&_satb_mark_queue_set),
1519 _dirty_card_queue(&_dirty_card_queue_set)
1520 #endif // INCLUDE_ALL_GCS
1521 {
1522 initialize();
1523 if (is_attaching_via_jni) {
1524 _jni_attach_state = _attaching_via_jni;
1525 } else {
1526 _jni_attach_state = _not_attaching_via_jni;
1527 }
1528 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1529 }
1530
1531 bool JavaThread::reguard_stack(address cur_sp) {
1532 if (_stack_guard_state != stack_guard_yellow_disabled) {
1533 return true; // Stack already guarded or guard pages not needed.
1534 }
1535
1536 if (register_stack_overflow()) {
1537 // For those architectures which have separate register and
1538 // memory stacks, we must check the register stack to see if
1539 // it has overflowed.
1540 return false;
1541 }
1542
1543 // Java code never executes within the yellow zone: the latter is only
1544 // there to provoke an exception during stack banging. If java code
1545 // is executing there, either StackShadowPages should be larger, or
1546 // some exception code in c1, c2 or the interpreter isn't unwinding
1547 // when it should.
1548 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1549
1550 enable_stack_yellow_zone();
1551 return true;
1552 }
1553
1554 bool JavaThread::reguard_stack(void) {
1555 return reguard_stack(os::current_stack_pointer());
1556 }
1557
1558
1559 void JavaThread::block_if_vm_exited() {
1560 if (_terminated == _vm_exited) {
1561 // _vm_exited is set at safepoint, and Threads_lock is never released
1562 // we will block here forever
1563 Threads_lock->lock_without_safepoint_check();
1564 ShouldNotReachHere();
1565 }
1566 }
1567
1568
1569 // Remove this ifdef when C1 is ported to the compiler interface.
1570 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1571
1572 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1573 Thread()
1574 #if INCLUDE_ALL_GCS
1575 , _satb_mark_queue(&_satb_mark_queue_set),
1576 _dirty_card_queue(&_dirty_card_queue_set)
1577 #endif // INCLUDE_ALL_GCS
1578 {
1579 if (TraceThreadEvents) {
1580 tty->print_cr("creating thread %p", this);
1581 }
1582 initialize();
1583 _jni_attach_state = _not_attaching_via_jni;
1584 set_entry_point(entry_point);
1585 // Create the native thread itself.
1586 // %note runtime_23
1587 os::ThreadType thr_type = os::java_thread;
1588 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1589 os::java_thread;
1590 os::create_thread(this, thr_type, stack_sz);
1591 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1592 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1593 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1594 // the exception consists of creating the exception object & initializing it, initialization
1595 // will leave the VM via a JavaCall and then all locks must be unlocked).
1596 //
1597 // The thread is still suspended when we reach here. Thread must be explicit started
1598 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1599 // by calling Threads:add. The reason why this is not done here, is because the thread
1600 // object must be fully initialized (take a look at JVM_Start)
1601 }
1602
1603 JavaThread::~JavaThread() {
1604 if (TraceThreadEvents) {
1605 tty->print_cr("terminate thread %p", this);
1606 }
1607
1608 // JSR166 -- return the parker to the free list
1609 Parker::Release(_parker);
1610 _parker = NULL ;
1611
1612 // Free any remaining previous UnrollBlock
1613 vframeArray* old_array = vframe_array_last();
1614
1615 if (old_array != NULL) {
1616 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1617 old_array->set_unroll_block(NULL);
1618 delete old_info;
1619 delete old_array;
1620 }
1621
1622 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1623 if (deferred != NULL) {
1624 // This can only happen if thread is destroyed before deoptimization occurs.
1625 assert(deferred->length() != 0, "empty array!");
1626 do {
1627 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1628 deferred->remove_at(0);
1629 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1630 delete dlv;
1631 } while (deferred->length() != 0);
1632 delete deferred;
1633 }
1634
1635 // All Java related clean up happens in exit
1636 ThreadSafepointState::destroy(this);
1637 if (_thread_profiler != NULL) delete _thread_profiler;
1638 if (_thread_stat != NULL) delete _thread_stat;
1639 }
1640
1641
1642 // The first routine called by a new Java thread
1643 void JavaThread::run() {
1644 // initialize thread-local alloc buffer related fields
1645 this->initialize_tlab();
1646
1647 // used to test validitity of stack trace backs
1648 this->record_base_of_stack_pointer();
1649
1650 // Record real stack base and size.
1651 this->record_stack_base_and_size();
1652
1653 // Initialize thread local storage; set before calling MutexLocker
1654 this->initialize_thread_local_storage();
1655
1656 this->create_stack_guard_pages();
1657
1658 this->cache_global_variables();
1659
1660 // Thread is now sufficient initialized to be handled by the safepoint code as being
1661 // in the VM. Change thread state from _thread_new to _thread_in_vm
1662 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1663
1664 assert(JavaThread::current() == this, "sanity check");
1665 assert(!Thread::current()->owns_locks(), "sanity check");
1666
1667 DTRACE_THREAD_PROBE(start, this);
1668
1669 // This operation might block. We call that after all safepoint checks for a new thread has
1670 // been completed.
1671 this->set_active_handles(JNIHandleBlock::allocate_block());
1672
1673 if (JvmtiExport::should_post_thread_life()) {
1674 JvmtiExport::post_thread_start(this);
1675 }
1676
1677 EventThreadStart event;
1678 if (event.should_commit()) {
1679 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1680 event.commit();
1681 }
1682
1683 // We call another function to do the rest so we are sure that the stack addresses used
1684 // from there will be lower than the stack base just computed
1685 thread_main_inner();
1686
1687 // Note, thread is no longer valid at this point!
1688 }
1689
1690
1691 void JavaThread::thread_main_inner() {
1692 assert(JavaThread::current() == this, "sanity check");
1693 assert(this->threadObj() != NULL, "just checking");
1694
1695 // Execute thread entry point unless this thread has a pending exception
1696 // or has been stopped before starting.
1697 // Note: Due to JVM_StopThread we can have pending exceptions already!
1698 if (!this->has_pending_exception() &&
1699 !java_lang_Thread::is_stillborn(this->threadObj())) {
1700 {
1701 ResourceMark rm(this);
1702 this->set_native_thread_name(this->get_thread_name());
1703 }
1704 HandleMark hm(this);
1705 this->entry_point()(this, this);
1706 }
1707
1708 DTRACE_THREAD_PROBE(stop, this);
1709
1710 this->exit(false);
1711 delete this;
1712 }
1713
1714
1715 static void ensure_join(JavaThread* thread) {
1716 // We do not need to grap the Threads_lock, since we are operating on ourself.
1717 Handle threadObj(thread, thread->threadObj());
1718 assert(threadObj.not_null(), "java thread object must exist");
1719 ObjectLocker lock(threadObj, thread);
1720 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1721 thread->clear_pending_exception();
1722 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1723 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1724 // Clear the native thread instance - this makes isAlive return false and allows the join()
1725 // to complete once we've done the notify_all below
1726 java_lang_Thread::set_thread(threadObj(), NULL);
1727 lock.notify_all(thread);
1728 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1729 thread->clear_pending_exception();
1730 }
1731
1732
1733 // For any new cleanup additions, please check to see if they need to be applied to
1734 // cleanup_failed_attach_current_thread as well.
1735 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1736 assert(this == JavaThread::current(), "thread consistency check");
1737
1738 HandleMark hm(this);
1739 Handle uncaught_exception(this, this->pending_exception());
1740 this->clear_pending_exception();
1741 Handle threadObj(this, this->threadObj());
1742 assert(threadObj.not_null(), "Java thread object should be created");
1743
1744 if (get_thread_profiler() != NULL) {
1745 get_thread_profiler()->disengage();
1746 ResourceMark rm;
1747 get_thread_profiler()->print(get_thread_name());
1748 }
1749
1750
1751 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1752 {
1753 EXCEPTION_MARK;
1754
1755 CLEAR_PENDING_EXCEPTION;
1756 }
1757 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1758 // has to be fixed by a runtime query method
1759 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1760 // JSR-166: change call from from ThreadGroup.uncaughtException to
1761 // java.lang.Thread.dispatchUncaughtException
1762 if (uncaught_exception.not_null()) {
1763 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1764 {
1765 EXCEPTION_MARK;
1766 // Check if the method Thread.dispatchUncaughtException() exists. If so
1767 // call it. Otherwise we have an older library without the JSR-166 changes,
1768 // so call ThreadGroup.uncaughtException()
1769 KlassHandle recvrKlass(THREAD, threadObj->klass());
1770 CallInfo callinfo;
1771 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1772 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1773 vmSymbols::dispatchUncaughtException_name(),
1774 vmSymbols::throwable_void_signature(),
1775 KlassHandle(), false, false, THREAD);
1776 CLEAR_PENDING_EXCEPTION;
1777 methodHandle method = callinfo.selected_method();
1778 if (method.not_null()) {
1779 JavaValue result(T_VOID);
1780 JavaCalls::call_virtual(&result,
1781 threadObj, thread_klass,
1782 vmSymbols::dispatchUncaughtException_name(),
1783 vmSymbols::throwable_void_signature(),
1784 uncaught_exception,
1785 THREAD);
1786 } else {
1787 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1788 JavaValue result(T_VOID);
1789 JavaCalls::call_virtual(&result,
1790 group, thread_group,
1791 vmSymbols::uncaughtException_name(),
1792 vmSymbols::thread_throwable_void_signature(),
1793 threadObj, // Arg 1
1794 uncaught_exception, // Arg 2
1795 THREAD);
1796 }
1797 if (HAS_PENDING_EXCEPTION) {
1798 ResourceMark rm(this);
1799 jio_fprintf(defaultStream::error_stream(),
1800 "\nException: %s thrown from the UncaughtExceptionHandler"
1801 " in thread \"%s\"\n",
1802 pending_exception()->klass()->external_name(),
1803 get_thread_name());
1804 CLEAR_PENDING_EXCEPTION;
1805 }
1806 }
1807 }
1808
1809 // Called before the java thread exit since we want to read info
1810 // from java_lang_Thread object
1811 EventThreadEnd event;
1812 if (event.should_commit()) {
1813 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1814 event.commit();
1815 }
1816
1817 // Call after last event on thread
1818 EVENT_THREAD_EXIT(this);
1819
1820 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1821 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1822 // is deprecated anyhow.
1823 if (!is_Compiler_thread()) {
1824 int count = 3;
1825 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1826 EXCEPTION_MARK;
1827 JavaValue result(T_VOID);
1828 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1829 JavaCalls::call_virtual(&result,
1830 threadObj, thread_klass,
1831 vmSymbols::exit_method_name(),
1832 vmSymbols::void_method_signature(),
1833 THREAD);
1834 CLEAR_PENDING_EXCEPTION;
1835 }
1836 }
1837 // notify JVMTI
1838 if (JvmtiExport::should_post_thread_life()) {
1839 JvmtiExport::post_thread_end(this);
1840 }
1841
1842 // We have notified the agents that we are exiting, before we go on,
1843 // we must check for a pending external suspend request and honor it
1844 // in order to not surprise the thread that made the suspend request.
1845 while (true) {
1846 {
1847 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1848 if (!is_external_suspend()) {
1849 set_terminated(_thread_exiting);
1850 ThreadService::current_thread_exiting(this);
1851 break;
1852 }
1853 // Implied else:
1854 // Things get a little tricky here. We have a pending external
1855 // suspend request, but we are holding the SR_lock so we
1856 // can't just self-suspend. So we temporarily drop the lock
1857 // and then self-suspend.
1858 }
1859
1860 ThreadBlockInVM tbivm(this);
1861 java_suspend_self();
1862
1863 // We're done with this suspend request, but we have to loop around
1864 // and check again. Eventually we will get SR_lock without a pending
1865 // external suspend request and will be able to mark ourselves as
1866 // exiting.
1867 }
1868 // no more external suspends are allowed at this point
1869 } else {
1870 // before_exit() has already posted JVMTI THREAD_END events
1871 }
1872
1873 // Notify waiters on thread object. This has to be done after exit() is called
1874 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1875 // group should have the destroyed bit set before waiters are notified).
1876 ensure_join(this);
1877 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1878
1879 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1880 // held by this thread must be released. A detach operation must only
1881 // get here if there are no Java frames on the stack. Therefore, any
1882 // owned monitors at this point MUST be JNI-acquired monitors which are
1883 // pre-inflated and in the monitor cache.
1884 //
1885 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1886 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1887 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1888 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1889 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1890 }
1891
1892 // These things needs to be done while we are still a Java Thread. Make sure that thread
1893 // is in a consistent state, in case GC happens
1894 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1895
1896 if (active_handles() != NULL) {
1897 JNIHandleBlock* block = active_handles();
1898 set_active_handles(NULL);
1899 JNIHandleBlock::release_block(block);
1900 }
1901
1902 if (free_handle_block() != NULL) {
1903 JNIHandleBlock* block = free_handle_block();
1904 set_free_handle_block(NULL);
1905 JNIHandleBlock::release_block(block);
1906 }
1907
1908 // These have to be removed while this is still a valid thread.
1909 remove_stack_guard_pages();
1910
1911 if (UseTLAB) {
1912 tlab().make_parsable(true); // retire TLAB
1913 }
1914
1915 if (JvmtiEnv::environments_might_exist()) {
1916 JvmtiExport::cleanup_thread(this);
1917 }
1918
1919 // We must flush any deferred card marks before removing a thread from
1920 // the list of active threads.
1921 Universe::heap()->flush_deferred_store_barrier(this);
1922 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1923
1924 #if INCLUDE_ALL_GCS
1925 // We must flush the G1-related buffers before removing a thread
1926 // from the list of active threads. We must do this after any deferred
1927 // card marks have been flushed (above) so that any entries that are
1928 // added to the thread's dirty card queue as a result are not lost.
1929 if (UseG1GC) {
1930 flush_barrier_queues();
1931 }
1932 #endif // INCLUDE_ALL_GCS
1933
1934 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1935 Threads::remove(this);
1936 }
1937
1938 #if INCLUDE_ALL_GCS
1939 // Flush G1-related queues.
1940 void JavaThread::flush_barrier_queues() {
1941 satb_mark_queue().flush();
1942 dirty_card_queue().flush();
1943 }
1944
1945 void JavaThread::initialize_queues() {
1946 assert(!SafepointSynchronize::is_at_safepoint(),
1947 "we should not be at a safepoint");
1948
1949 ObjPtrQueue& satb_queue = satb_mark_queue();
1950 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1951 // The SATB queue should have been constructed with its active
1952 // field set to false.
1953 assert(!satb_queue.is_active(), "SATB queue should not be active");
1954 assert(satb_queue.is_empty(), "SATB queue should be empty");
1955 // If we are creating the thread during a marking cycle, we should
1956 // set the active field of the SATB queue to true.
1957 if (satb_queue_set.is_active()) {
1958 satb_queue.set_active(true);
1959 }
1960
1961 DirtyCardQueue& dirty_queue = dirty_card_queue();
1962 // The dirty card queue should have been constructed with its
1963 // active field set to true.
1964 assert(dirty_queue.is_active(), "dirty card queue should be active");
1965 }
1966 #endif // INCLUDE_ALL_GCS
1967
1968 void JavaThread::cleanup_failed_attach_current_thread() {
1969 if (get_thread_profiler() != NULL) {
1970 get_thread_profiler()->disengage();
1971 ResourceMark rm;
1972 get_thread_profiler()->print(get_thread_name());
1973 }
1974
1975 if (active_handles() != NULL) {
1976 JNIHandleBlock* block = active_handles();
1977 set_active_handles(NULL);
1978 JNIHandleBlock::release_block(block);
1979 }
1980
1981 if (free_handle_block() != NULL) {
1982 JNIHandleBlock* block = free_handle_block();
1983 set_free_handle_block(NULL);
1984 JNIHandleBlock::release_block(block);
1985 }
1986
1987 // These have to be removed while this is still a valid thread.
1988 remove_stack_guard_pages();
1989
1990 if (UseTLAB) {
1991 tlab().make_parsable(true); // retire TLAB, if any
1992 }
1993
1994 #if INCLUDE_ALL_GCS
1995 if (UseG1GC) {
1996 flush_barrier_queues();
1997 }
1998 #endif // INCLUDE_ALL_GCS
1999
2000 Threads::remove(this);
2001 delete this;
2002 }
2003
2004
2005
2006
2007 JavaThread* JavaThread::active() {
2008 Thread* thread = ThreadLocalStorage::thread();
2009 assert(thread != NULL, "just checking");
2010 if (thread->is_Java_thread()) {
2011 return (JavaThread*) thread;
2012 } else {
2013 assert(thread->is_VM_thread(), "this must be a vm thread");
2014 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2015 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2016 assert(ret->is_Java_thread(), "must be a Java thread");
2017 return ret;
2018 }
2019 }
2020
2021 bool JavaThread::is_lock_owned(address adr) const {
2022 if (Thread::is_lock_owned(adr)) return true;
2023
2024 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2025 if (chunk->contains(adr)) return true;
2026 }
2027
2028 return false;
2029 }
2030
2031
2032 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2033 chunk->set_next(monitor_chunks());
2034 set_monitor_chunks(chunk);
2035 }
2036
2037 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2038 guarantee(monitor_chunks() != NULL, "must be non empty");
2039 if (monitor_chunks() == chunk) {
2040 set_monitor_chunks(chunk->next());
2041 } else {
2042 MonitorChunk* prev = monitor_chunks();
2043 while (prev->next() != chunk) prev = prev->next();
2044 prev->set_next(chunk->next());
2045 }
2046 }
2047
2048 // JVM support.
2049
2050 // Note: this function shouldn't block if it's called in
2051 // _thread_in_native_trans state (such as from
2052 // check_special_condition_for_native_trans()).
2053 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2054
2055 if (has_last_Java_frame() && has_async_condition()) {
2056 // If we are at a polling page safepoint (not a poll return)
2057 // then we must defer async exception because live registers
2058 // will be clobbered by the exception path. Poll return is
2059 // ok because the call we a returning from already collides
2060 // with exception handling registers and so there is no issue.
2061 // (The exception handling path kills call result registers but
2062 // this is ok since the exception kills the result anyway).
2063
2064 if (is_at_poll_safepoint()) {
2065 // if the code we are returning to has deoptimized we must defer
2066 // the exception otherwise live registers get clobbered on the
2067 // exception path before deoptimization is able to retrieve them.
2068 //
2069 RegisterMap map(this, false);
2070 frame caller_fr = last_frame().sender(&map);
2071 assert(caller_fr.is_compiled_frame(), "what?");
2072 if (caller_fr.is_deoptimized_frame()) {
2073 if (TraceExceptions) {
2074 ResourceMark rm;
2075 tty->print_cr("deferred async exception at compiled safepoint");
2076 }
2077 return;
2078 }
2079 }
2080 }
2081
2082 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2083 if (condition == _no_async_condition) {
2084 // Conditions have changed since has_special_runtime_exit_condition()
2085 // was called:
2086 // - if we were here only because of an external suspend request,
2087 // then that was taken care of above (or cancelled) so we are done
2088 // - if we were here because of another async request, then it has
2089 // been cleared between the has_special_runtime_exit_condition()
2090 // and now so again we are done
2091 return;
2092 }
2093
2094 // Check for pending async. exception
2095 if (_pending_async_exception != NULL) {
2096 // Only overwrite an already pending exception, if it is not a threadDeath.
2097 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2098
2099 // We cannot call Exceptions::_throw(...) here because we cannot block
2100 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2101
2102 if (TraceExceptions) {
2103 ResourceMark rm;
2104 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2105 if (has_last_Java_frame() ) {
2106 frame f = last_frame();
2107 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2108 }
2109 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2110 }
2111 _pending_async_exception = NULL;
2112 clear_has_async_exception();
2113 }
2114 }
2115
2116 if (check_unsafe_error &&
2117 condition == _async_unsafe_access_error && !has_pending_exception()) {
2118 condition = _no_async_condition; // done
2119 switch (thread_state()) {
2120 case _thread_in_vm:
2121 {
2122 JavaThread* THREAD = this;
2123 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2124 }
2125 case _thread_in_native:
2126 {
2127 ThreadInVMfromNative tiv(this);
2128 JavaThread* THREAD = this;
2129 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2130 }
2131 case _thread_in_Java:
2132 {
2133 ThreadInVMfromJava tiv(this);
2134 JavaThread* THREAD = this;
2135 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2136 }
2137 default:
2138 ShouldNotReachHere();
2139 }
2140 }
2141
2142 assert(condition == _no_async_condition || has_pending_exception() ||
2143 (!check_unsafe_error && condition == _async_unsafe_access_error),
2144 "must have handled the async condition, if no exception");
2145 }
2146
2147 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2148 //
2149 // Check for pending external suspend. Internal suspend requests do
2150 // not use handle_special_runtime_exit_condition().
2151 // If JNIEnv proxies are allowed, don't self-suspend if the target
2152 // thread is not the current thread. In older versions of jdbx, jdbx
2153 // threads could call into the VM with another thread's JNIEnv so we
2154 // can be here operating on behalf of a suspended thread (4432884).
2155 bool do_self_suspend = is_external_suspend_with_lock();
2156 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2157 //
2158 // Because thread is external suspended the safepoint code will count
2159 // thread as at a safepoint. This can be odd because we can be here
2160 // as _thread_in_Java which would normally transition to _thread_blocked
2161 // at a safepoint. We would like to mark the thread as _thread_blocked
2162 // before calling java_suspend_self like all other callers of it but
2163 // we must then observe proper safepoint protocol. (We can't leave
2164 // _thread_blocked with a safepoint in progress). However we can be
2165 // here as _thread_in_native_trans so we can't use a normal transition
2166 // constructor/destructor pair because they assert on that type of
2167 // transition. We could do something like:
2168 //
2169 // JavaThreadState state = thread_state();
2170 // set_thread_state(_thread_in_vm);
2171 // {
2172 // ThreadBlockInVM tbivm(this);
2173 // java_suspend_self()
2174 // }
2175 // set_thread_state(_thread_in_vm_trans);
2176 // if (safepoint) block;
2177 // set_thread_state(state);
2178 //
2179 // but that is pretty messy. Instead we just go with the way the
2180 // code has worked before and note that this is the only path to
2181 // java_suspend_self that doesn't put the thread in _thread_blocked
2182 // mode.
2183
2184 frame_anchor()->make_walkable(this);
2185 java_suspend_self();
2186
2187 // We might be here for reasons in addition to the self-suspend request
2188 // so check for other async requests.
2189 }
2190
2191 if (check_asyncs) {
2192 check_and_handle_async_exceptions();
2193 }
2194 }
2195
2196 void JavaThread::send_thread_stop(oop java_throwable) {
2197 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2198 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2199 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2200
2201 // Do not throw asynchronous exceptions against the compiler thread
2202 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2203 if (is_Compiler_thread()) return;
2204
2205 {
2206 // Actually throw the Throwable against the target Thread - however
2207 // only if there is no thread death exception installed already.
2208 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2209 // If the topmost frame is a runtime stub, then we are calling into
2210 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2211 // must deoptimize the caller before continuing, as the compiled exception handler table
2212 // may not be valid
2213 if (has_last_Java_frame()) {
2214 frame f = last_frame();
2215 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2216 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2217 RegisterMap reg_map(this, UseBiasedLocking);
2218 frame compiled_frame = f.sender(®_map);
2219 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2220 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2221 }
2222 }
2223 }
2224
2225 // Set async. pending exception in thread.
2226 set_pending_async_exception(java_throwable);
2227
2228 if (TraceExceptions) {
2229 ResourceMark rm;
2230 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2231 }
2232 // for AbortVMOnException flag
2233 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2234 }
2235 }
2236
2237
2238 // Interrupt thread so it will wake up from a potential wait()
2239 Thread::interrupt(this);
2240 }
2241
2242 // External suspension mechanism.
2243 //
2244 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2245 // to any VM_locks and it is at a transition
2246 // Self-suspension will happen on the transition out of the vm.
2247 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2248 //
2249 // Guarantees on return:
2250 // + Target thread will not execute any new bytecode (that's why we need to
2251 // force a safepoint)
2252 // + Target thread will not enter any new monitors
2253 //
2254 void JavaThread::java_suspend() {
2255 { MutexLocker mu(Threads_lock);
2256 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2257 return;
2258 }
2259 }
2260
2261 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2262 if (!is_external_suspend()) {
2263 // a racing resume has cancelled us; bail out now
2264 return;
2265 }
2266
2267 // suspend is done
2268 uint32_t debug_bits = 0;
2269 // Warning: is_ext_suspend_completed() may temporarily drop the
2270 // SR_lock to allow the thread to reach a stable thread state if
2271 // it is currently in a transient thread state.
2272 if (is_ext_suspend_completed(false /* !called_by_wait */,
2273 SuspendRetryDelay, &debug_bits) ) {
2274 return;
2275 }
2276 }
2277
2278 VM_ForceSafepoint vm_suspend;
2279 VMThread::execute(&vm_suspend);
2280 }
2281
2282 // Part II of external suspension.
2283 // A JavaThread self suspends when it detects a pending external suspend
2284 // request. This is usually on transitions. It is also done in places
2285 // where continuing to the next transition would surprise the caller,
2286 // e.g., monitor entry.
2287 //
2288 // Returns the number of times that the thread self-suspended.
2289 //
2290 // Note: DO NOT call java_suspend_self() when you just want to block current
2291 // thread. java_suspend_self() is the second stage of cooperative
2292 // suspension for external suspend requests and should only be used
2293 // to complete an external suspend request.
2294 //
2295 int JavaThread::java_suspend_self() {
2296 int ret = 0;
2297
2298 // we are in the process of exiting so don't suspend
2299 if (is_exiting()) {
2300 clear_external_suspend();
2301 return ret;
2302 }
2303
2304 assert(_anchor.walkable() ||
2305 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2306 "must have walkable stack");
2307
2308 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2309
2310 assert(!this->is_ext_suspended(),
2311 "a thread trying to self-suspend should not already be suspended");
2312
2313 if (this->is_suspend_equivalent()) {
2314 // If we are self-suspending as a result of the lifting of a
2315 // suspend equivalent condition, then the suspend_equivalent
2316 // flag is not cleared until we set the ext_suspended flag so
2317 // that wait_for_ext_suspend_completion() returns consistent
2318 // results.
2319 this->clear_suspend_equivalent();
2320 }
2321
2322 // A racing resume may have cancelled us before we grabbed SR_lock
2323 // above. Or another external suspend request could be waiting for us
2324 // by the time we return from SR_lock()->wait(). The thread
2325 // that requested the suspension may already be trying to walk our
2326 // stack and if we return now, we can change the stack out from under
2327 // it. This would be a "bad thing (TM)" and cause the stack walker
2328 // to crash. We stay self-suspended until there are no more pending
2329 // external suspend requests.
2330 while (is_external_suspend()) {
2331 ret++;
2332 this->set_ext_suspended();
2333
2334 // _ext_suspended flag is cleared by java_resume()
2335 while (is_ext_suspended()) {
2336 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2337 }
2338 }
2339
2340 return ret;
2341 }
2342
2343 #ifdef ASSERT
2344 // verify the JavaThread has not yet been published in the Threads::list, and
2345 // hence doesn't need protection from concurrent access at this stage
2346 void JavaThread::verify_not_published() {
2347 if (!Threads_lock->owned_by_self()) {
2348 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2349 assert( !Threads::includes(this),
2350 "java thread shouldn't have been published yet!");
2351 }
2352 else {
2353 assert( !Threads::includes(this),
2354 "java thread shouldn't have been published yet!");
2355 }
2356 }
2357 #endif
2358
2359 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2360 // progress or when _suspend_flags is non-zero.
2361 // Current thread needs to self-suspend if there is a suspend request and/or
2362 // block if a safepoint is in progress.
2363 // Async exception ISN'T checked.
2364 // Note only the ThreadInVMfromNative transition can call this function
2365 // directly and when thread state is _thread_in_native_trans
2366 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2367 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2368
2369 JavaThread *curJT = JavaThread::current();
2370 bool do_self_suspend = thread->is_external_suspend();
2371
2372 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2373
2374 // If JNIEnv proxies are allowed, don't self-suspend if the target
2375 // thread is not the current thread. In older versions of jdbx, jdbx
2376 // threads could call into the VM with another thread's JNIEnv so we
2377 // can be here operating on behalf of a suspended thread (4432884).
2378 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2379 JavaThreadState state = thread->thread_state();
2380
2381 // We mark this thread_blocked state as a suspend-equivalent so
2382 // that a caller to is_ext_suspend_completed() won't be confused.
2383 // The suspend-equivalent state is cleared by java_suspend_self().
2384 thread->set_suspend_equivalent();
2385
2386 // If the safepoint code sees the _thread_in_native_trans state, it will
2387 // wait until the thread changes to other thread state. There is no
2388 // guarantee on how soon we can obtain the SR_lock and complete the
2389 // self-suspend request. It would be a bad idea to let safepoint wait for
2390 // too long. Temporarily change the state to _thread_blocked to
2391 // let the VM thread know that this thread is ready for GC. The problem
2392 // of changing thread state is that safepoint could happen just after
2393 // java_suspend_self() returns after being resumed, and VM thread will
2394 // see the _thread_blocked state. We must check for safepoint
2395 // after restoring the state and make sure we won't leave while a safepoint
2396 // is in progress.
2397 thread->set_thread_state(_thread_blocked);
2398 thread->java_suspend_self();
2399 thread->set_thread_state(state);
2400 // Make sure new state is seen by VM thread
2401 if (os::is_MP()) {
2402 if (UseMembar) {
2403 // Force a fence between the write above and read below
2404 OrderAccess::fence();
2405 } else {
2406 // Must use this rather than serialization page in particular on Windows
2407 InterfaceSupport::serialize_memory(thread);
2408 }
2409 }
2410 }
2411
2412 if (SafepointSynchronize::do_call_back()) {
2413 // If we are safepointing, then block the caller which may not be
2414 // the same as the target thread (see above).
2415 SafepointSynchronize::block(curJT);
2416 }
2417
2418 if (thread->is_deopt_suspend()) {
2419 thread->clear_deopt_suspend();
2420 RegisterMap map(thread, false);
2421 frame f = thread->last_frame();
2422 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2423 f = f.sender(&map);
2424 }
2425 if (f.id() == thread->must_deopt_id()) {
2426 thread->clear_must_deopt_id();
2427 f.deoptimize(thread);
2428 } else {
2429 fatal("missed deoptimization!");
2430 }
2431 }
2432 }
2433
2434 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2435 // progress or when _suspend_flags is non-zero.
2436 // Current thread needs to self-suspend if there is a suspend request and/or
2437 // block if a safepoint is in progress.
2438 // Also check for pending async exception (not including unsafe access error).
2439 // Note only the native==>VM/Java barriers can call this function and when
2440 // thread state is _thread_in_native_trans.
2441 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2442 check_safepoint_and_suspend_for_native_trans(thread);
2443
2444 if (thread->has_async_exception()) {
2445 // We are in _thread_in_native_trans state, don't handle unsafe
2446 // access error since that may block.
2447 thread->check_and_handle_async_exceptions(false);
2448 }
2449 }
2450
2451 // This is a variant of the normal
2452 // check_special_condition_for_native_trans with slightly different
2453 // semantics for use by critical native wrappers. It does all the
2454 // normal checks but also performs the transition back into
2455 // thread_in_Java state. This is required so that critical natives
2456 // can potentially block and perform a GC if they are the last thread
2457 // exiting the GC_locker.
2458 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2459 check_special_condition_for_native_trans(thread);
2460
2461 // Finish the transition
2462 thread->set_thread_state(_thread_in_Java);
2463
2464 if (thread->do_critical_native_unlock()) {
2465 ThreadInVMfromJavaNoAsyncException tiv(thread);
2466 GC_locker::unlock_critical(thread);
2467 thread->clear_critical_native_unlock();
2468 }
2469 }
2470
2471 // We need to guarantee the Threads_lock here, since resumes are not
2472 // allowed during safepoint synchronization
2473 // Can only resume from an external suspension
2474 void JavaThread::java_resume() {
2475 assert_locked_or_safepoint(Threads_lock);
2476
2477 // Sanity check: thread is gone, has started exiting or the thread
2478 // was not externally suspended.
2479 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2480 return;
2481 }
2482
2483 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2484
2485 clear_external_suspend();
2486
2487 if (is_ext_suspended()) {
2488 clear_ext_suspended();
2489 SR_lock()->notify_all();
2490 }
2491 }
2492
2493 void JavaThread::create_stack_guard_pages() {
2494 if (!os::uses_stack_guard_pages() ||
2495 _stack_guard_state != stack_guard_unused ||
2496 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2497 if (TraceThreadEvents) {
2498 tty->print_cr("Stack guard page creation for thread "
2499 UINTX_FORMAT " disabled", os::current_thread_id());
2500 }
2501 return;
2502 }
2503 address low_addr = stack_base() - stack_size();
2504 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2505
2506 int allocate = os::allocate_stack_guard_pages();
2507 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2508
2509 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2510 warning("Attempt to allocate stack guard pages failed.");
2511 return;
2512 }
2513
2514 if (os::guard_memory((char *) low_addr, len)) {
2515 _stack_guard_state = stack_guard_enabled;
2516 } else {
2517 warning("Attempt to protect stack guard pages failed.");
2518 if (os::uncommit_memory((char *) low_addr, len)) {
2519 warning("Attempt to deallocate stack guard pages failed.");
2520 }
2521 }
2522 }
2523
2524 void JavaThread::remove_stack_guard_pages() {
2525 assert(Thread::current() == this, "from different thread");
2526 if (_stack_guard_state == stack_guard_unused) return;
2527 address low_addr = stack_base() - stack_size();
2528 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2529
2530 if (os::allocate_stack_guard_pages()) {
2531 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2532 _stack_guard_state = stack_guard_unused;
2533 } else {
2534 warning("Attempt to deallocate stack guard pages failed.");
2535 }
2536 } else {
2537 if (_stack_guard_state == stack_guard_unused) return;
2538 if (os::unguard_memory((char *) low_addr, len)) {
2539 _stack_guard_state = stack_guard_unused;
2540 } else {
2541 warning("Attempt to unprotect stack guard pages failed.");
2542 }
2543 }
2544 }
2545
2546 void JavaThread::enable_stack_yellow_zone() {
2547 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2548 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2549
2550 // The base notation is from the stacks point of view, growing downward.
2551 // We need to adjust it to work correctly with guard_memory()
2552 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2553
2554 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2555 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2556
2557 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2558 _stack_guard_state = stack_guard_enabled;
2559 } else {
2560 warning("Attempt to guard stack yellow zone failed.");
2561 }
2562 enable_register_stack_guard();
2563 }
2564
2565 void JavaThread::disable_stack_yellow_zone() {
2566 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2567 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2568
2569 // Simply return if called for a thread that does not use guard pages.
2570 if (_stack_guard_state == stack_guard_unused) return;
2571
2572 // The base notation is from the stacks point of view, growing downward.
2573 // We need to adjust it to work correctly with guard_memory()
2574 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2575
2576 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2577 _stack_guard_state = stack_guard_yellow_disabled;
2578 } else {
2579 warning("Attempt to unguard stack yellow zone failed.");
2580 }
2581 disable_register_stack_guard();
2582 }
2583
2584 void JavaThread::enable_stack_red_zone() {
2585 // The base notation is from the stacks point of view, growing downward.
2586 // We need to adjust it to work correctly with guard_memory()
2587 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2588 address base = stack_red_zone_base() - stack_red_zone_size();
2589
2590 guarantee(base < stack_base(),"Error calculating stack red zone");
2591 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2592
2593 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2594 warning("Attempt to guard stack red zone failed.");
2595 }
2596 }
2597
2598 void JavaThread::disable_stack_red_zone() {
2599 // The base notation is from the stacks point of view, growing downward.
2600 // We need to adjust it to work correctly with guard_memory()
2601 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2602 address base = stack_red_zone_base() - stack_red_zone_size();
2603 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2604 warning("Attempt to unguard stack red zone failed.");
2605 }
2606 }
2607
2608 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2609 // ignore is there is no stack
2610 if (!has_last_Java_frame()) return;
2611 // traverse the stack frames. Starts from top frame.
2612 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2613 frame* fr = fst.current();
2614 f(fr, fst.register_map());
2615 }
2616 }
2617
2618
2619 #ifndef PRODUCT
2620 // Deoptimization
2621 // Function for testing deoptimization
2622 void JavaThread::deoptimize() {
2623 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2624 StackFrameStream fst(this, UseBiasedLocking);
2625 bool deopt = false; // Dump stack only if a deopt actually happens.
2626 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2627 // Iterate over all frames in the thread and deoptimize
2628 for(; !fst.is_done(); fst.next()) {
2629 if(fst.current()->can_be_deoptimized()) {
2630
2631 if (only_at) {
2632 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2633 // consists of comma or carriage return separated numbers so
2634 // search for the current bci in that string.
2635 address pc = fst.current()->pc();
2636 nmethod* nm = (nmethod*) fst.current()->cb();
2637 ScopeDesc* sd = nm->scope_desc_at( pc);
2638 char buffer[8];
2639 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2640 size_t len = strlen(buffer);
2641 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2642 while (found != NULL) {
2643 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2644 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2645 // Check that the bci found is bracketed by terminators.
2646 break;
2647 }
2648 found = strstr(found + 1, buffer);
2649 }
2650 if (!found) {
2651 continue;
2652 }
2653 }
2654
2655 if (DebugDeoptimization && !deopt) {
2656 deopt = true; // One-time only print before deopt
2657 tty->print_cr("[BEFORE Deoptimization]");
2658 trace_frames();
2659 trace_stack();
2660 }
2661 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2662 }
2663 }
2664
2665 if (DebugDeoptimization && deopt) {
2666 tty->print_cr("[AFTER Deoptimization]");
2667 trace_frames();
2668 }
2669 }
2670
2671
2672 // Make zombies
2673 void JavaThread::make_zombies() {
2674 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2675 if (fst.current()->can_be_deoptimized()) {
2676 // it is a Java nmethod
2677 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2678 nm->make_not_entrant();
2679 }
2680 }
2681 }
2682 #endif // PRODUCT
2683
2684
2685 void JavaThread::deoptimized_wrt_marked_nmethods() {
2686 if (!has_last_Java_frame()) return;
2687 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2688 StackFrameStream fst(this, UseBiasedLocking);
2689 for(; !fst.is_done(); fst.next()) {
2690 if (fst.current()->should_be_deoptimized()) {
2691 if (LogCompilation && xtty != NULL) {
2692 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2693 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2694 this->name(), nm != NULL ? nm->compile_id() : -1);
2695 }
2696
2697 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2698 }
2699 }
2700 }
2701
2702
2703 // GC support
2704 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2705
2706 void JavaThread::gc_epilogue() {
2707 frames_do(frame_gc_epilogue);
2708 }
2709
2710
2711 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2712
2713 void JavaThread::gc_prologue() {
2714 frames_do(frame_gc_prologue);
2715 }
2716
2717 // If the caller is a NamedThread, then remember, in the current scope,
2718 // the given JavaThread in its _processed_thread field.
2719 class RememberProcessedThread: public StackObj {
2720 NamedThread* _cur_thr;
2721 public:
2722 RememberProcessedThread(JavaThread* jthr) {
2723 Thread* thread = Thread::current();
2724 if (thread->is_Named_thread()) {
2725 _cur_thr = (NamedThread *)thread;
2726 _cur_thr->set_processed_thread(jthr);
2727 } else {
2728 _cur_thr = NULL;
2729 }
2730 }
2731
2732 ~RememberProcessedThread() {
2733 if (_cur_thr) {
2734 _cur_thr->set_processed_thread(NULL);
2735 }
2736 }
2737 };
2738
2739 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2740 // Verify that the deferred card marks have been flushed.
2741 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2742
2743 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2744 // since there may be more than one thread using each ThreadProfiler.
2745
2746 // Traverse the GCHandles
2747 Thread::oops_do(f, cld_f, cf);
2748
2749 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2750 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2751
2752 if (has_last_Java_frame()) {
2753 // Record JavaThread to GC thread
2754 RememberProcessedThread rpt(this);
2755
2756 // Traverse the privileged stack
2757 if (_privileged_stack_top != NULL) {
2758 _privileged_stack_top->oops_do(f);
2759 }
2760
2761 // traverse the registered growable array
2762 if (_array_for_gc != NULL) {
2763 for (int index = 0; index < _array_for_gc->length(); index++) {
2764 f->do_oop(_array_for_gc->adr_at(index));
2765 }
2766 }
2767
2768 // Traverse the monitor chunks
2769 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2770 chunk->oops_do(f);
2771 }
2772
2773 // Traverse the execution stack
2774 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2775 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2776 }
2777 }
2778
2779 // callee_target is never live across a gc point so NULL it here should
2780 // it still contain a methdOop.
2781
2782 set_callee_target(NULL);
2783
2784 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2785 // If we have deferred set_locals there might be oops waiting to be
2786 // written
2787 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2788 if (list != NULL) {
2789 for (int i = 0; i < list->length(); i++) {
2790 list->at(i)->oops_do(f);
2791 }
2792 }
2793
2794 // Traverse instance variables at the end since the GC may be moving things
2795 // around using this function
2796 f->do_oop((oop*) &_threadObj);
2797 f->do_oop((oop*) &_vm_result);
2798 f->do_oop((oop*) &_exception_oop);
2799 f->do_oop((oop*) &_pending_async_exception);
2800
2801 if (jvmti_thread_state() != NULL) {
2802 jvmti_thread_state()->oops_do(f);
2803 }
2804 }
2805
2806 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2807 Thread::nmethods_do(cf); // (super method is a no-op)
2808
2809 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2810 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2811
2812 if (has_last_Java_frame()) {
2813 // Traverse the execution stack
2814 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2815 fst.current()->nmethods_do(cf);
2816 }
2817 }
2818 }
2819
2820 void JavaThread::metadata_do(void f(Metadata*)) {
2821 Thread::metadata_do(f);
2822 if (has_last_Java_frame()) {
2823 // Traverse the execution stack to call f() on the methods in the stack
2824 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2825 fst.current()->metadata_do(f);
2826 }
2827 } else if (is_Compiler_thread()) {
2828 // need to walk ciMetadata in current compile tasks to keep alive.
2829 CompilerThread* ct = (CompilerThread*)this;
2830 if (ct->env() != NULL) {
2831 ct->env()->metadata_do(f);
2832 }
2833 }
2834 }
2835
2836 // Printing
2837 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2838 switch (_thread_state) {
2839 case _thread_uninitialized: return "_thread_uninitialized";
2840 case _thread_new: return "_thread_new";
2841 case _thread_new_trans: return "_thread_new_trans";
2842 case _thread_in_native: return "_thread_in_native";
2843 case _thread_in_native_trans: return "_thread_in_native_trans";
2844 case _thread_in_vm: return "_thread_in_vm";
2845 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2846 case _thread_in_Java: return "_thread_in_Java";
2847 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2848 case _thread_blocked: return "_thread_blocked";
2849 case _thread_blocked_trans: return "_thread_blocked_trans";
2850 default: return "unknown thread state";
2851 }
2852 }
2853
2854 #ifndef PRODUCT
2855 void JavaThread::print_thread_state_on(outputStream *st) const {
2856 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2857 };
2858 void JavaThread::print_thread_state() const {
2859 print_thread_state_on(tty);
2860 };
2861 #endif // PRODUCT
2862
2863 // Called by Threads::print() for VM_PrintThreads operation
2864 void JavaThread::print_on(outputStream *st) const {
2865 st->print("\"%s\" ", get_thread_name());
2866 oop thread_oop = threadObj();
2867 if (thread_oop != NULL) {
2868 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2869 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2870 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2871 }
2872 Thread::print_on(st);
2873 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2874 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2875 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2876 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2877 }
2878 #ifndef PRODUCT
2879 print_thread_state_on(st);
2880 _safepoint_state->print_on(st);
2881 #endif // PRODUCT
2882 }
2883
2884 // Called by fatal error handler. The difference between this and
2885 // JavaThread::print() is that we can't grab lock or allocate memory.
2886 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2887 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2888 oop thread_obj = threadObj();
2889 if (thread_obj != NULL) {
2890 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2891 }
2892 st->print(" [");
2893 st->print("%s", _get_thread_state_name(_thread_state));
2894 if (osthread()) {
2895 st->print(", id=%d", osthread()->thread_id());
2896 }
2897 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2898 _stack_base - _stack_size, _stack_base);
2899 st->print("]");
2900 return;
2901 }
2902
2903 // Verification
2904
2905 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2906
2907 void JavaThread::verify() {
2908 // Verify oops in the thread.
2909 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2910
2911 // Verify the stack frames.
2912 frames_do(frame_verify);
2913 }
2914
2915 // CR 6300358 (sub-CR 2137150)
2916 // Most callers of this method assume that it can't return NULL but a
2917 // thread may not have a name whilst it is in the process of attaching to
2918 // the VM - see CR 6412693, and there are places where a JavaThread can be
2919 // seen prior to having it's threadObj set (eg JNI attaching threads and
2920 // if vm exit occurs during initialization). These cases can all be accounted
2921 // for such that this method never returns NULL.
2922 const char* JavaThread::get_thread_name() const {
2923 #ifdef ASSERT
2924 // early safepoints can hit while current thread does not yet have TLS
2925 if (!SafepointSynchronize::is_at_safepoint()) {
2926 Thread *cur = Thread::current();
2927 if (!(cur->is_Java_thread() && cur == this)) {
2928 // Current JavaThreads are allowed to get their own name without
2929 // the Threads_lock.
2930 assert_locked_or_safepoint(Threads_lock);
2931 }
2932 }
2933 #endif // ASSERT
2934 return get_thread_name_string();
2935 }
2936
2937 // Returns a non-NULL representation of this thread's name, or a suitable
2938 // descriptive string if there is no set name
2939 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2940 const char* name_str;
2941 oop thread_obj = threadObj();
2942 if (thread_obj != NULL) {
2943 oop name = java_lang_Thread::name(thread_obj);
2944 if (name != NULL) {
2945 if (buf == NULL) {
2946 name_str = java_lang_String::as_utf8_string(name);
2947 }
2948 else {
2949 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2950 }
2951 }
2952 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2953 name_str = "<no-name - thread is attaching>";
2954 }
2955 else {
2956 name_str = Thread::name();
2957 }
2958 }
2959 else {
2960 name_str = Thread::name();
2961 }
2962 assert(name_str != NULL, "unexpected NULL thread name");
2963 return name_str;
2964 }
2965
2966
2967 const char* JavaThread::get_threadgroup_name() const {
2968 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2969 oop thread_obj = threadObj();
2970 if (thread_obj != NULL) {
2971 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2972 if (thread_group != NULL) {
2973 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2974 // ThreadGroup.name can be null
2975 if (name != NULL) {
2976 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2977 return str;
2978 }
2979 }
2980 }
2981 return NULL;
2982 }
2983
2984 const char* JavaThread::get_parent_name() const {
2985 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2986 oop thread_obj = threadObj();
2987 if (thread_obj != NULL) {
2988 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2989 if (thread_group != NULL) {
2990 oop parent = java_lang_ThreadGroup::parent(thread_group);
2991 if (parent != NULL) {
2992 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2993 // ThreadGroup.name can be null
2994 if (name != NULL) {
2995 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2996 return str;
2997 }
2998 }
2999 }
3000 }
3001 return NULL;
3002 }
3003
3004 ThreadPriority JavaThread::java_priority() const {
3005 oop thr_oop = threadObj();
3006 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3007 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3008 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3009 return priority;
3010 }
3011
3012 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3013
3014 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3015 // Link Java Thread object <-> C++ Thread
3016
3017 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3018 // and put it into a new Handle. The Handle "thread_oop" can then
3019 // be used to pass the C++ thread object to other methods.
3020
3021 // Set the Java level thread object (jthread) field of the
3022 // new thread (a JavaThread *) to C++ thread object using the
3023 // "thread_oop" handle.
3024
3025 // Set the thread field (a JavaThread *) of the
3026 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3027
3028 Handle thread_oop(Thread::current(),
3029 JNIHandles::resolve_non_null(jni_thread));
3030 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3031 "must be initialized");
3032 set_threadObj(thread_oop());
3033 java_lang_Thread::set_thread(thread_oop(), this);
3034
3035 if (prio == NoPriority) {
3036 prio = java_lang_Thread::priority(thread_oop());
3037 assert(prio != NoPriority, "A valid priority should be present");
3038 }
3039
3040 // Push the Java priority down to the native thread; needs Threads_lock
3041 Thread::set_priority(this, prio);
3042
3043 prepare_ext();
3044
3045 // Add the new thread to the Threads list and set it in motion.
3046 // We must have threads lock in order to call Threads::add.
3047 // It is crucial that we do not block before the thread is
3048 // added to the Threads list for if a GC happens, then the java_thread oop
3049 // will not be visited by GC.
3050 Threads::add(this);
3051 }
3052
3053 oop JavaThread::current_park_blocker() {
3054 // Support for JSR-166 locks
3055 oop thread_oop = threadObj();
3056 if (thread_oop != NULL &&
3057 JDK_Version::current().supports_thread_park_blocker()) {
3058 return java_lang_Thread::park_blocker(thread_oop);
3059 }
3060 return NULL;
3061 }
3062
3063
3064 void JavaThread::print_stack_on(outputStream* st) {
3065 if (!has_last_Java_frame()) return;
3066 ResourceMark rm;
3067 HandleMark hm;
3068
3069 RegisterMap reg_map(this);
3070 vframe* start_vf = last_java_vframe(®_map);
3071 int count = 0;
3072 for (vframe* f = start_vf; f; f = f->sender() ) {
3073 if (f->is_java_frame()) {
3074 javaVFrame* jvf = javaVFrame::cast(f);
3075 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3076
3077 // Print out lock information
3078 if (JavaMonitorsInStackTrace) {
3079 jvf->print_lock_info_on(st, count);
3080 }
3081 } else {
3082 // Ignore non-Java frames
3083 }
3084
3085 // Bail-out case for too deep stacks
3086 count++;
3087 if (MaxJavaStackTraceDepth == count) return;
3088 }
3089 }
3090
3091
3092 // JVMTI PopFrame support
3093 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3094 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3095 if (in_bytes(size_in_bytes) != 0) {
3096 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3097 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3098 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3099 }
3100 }
3101
3102 void* JavaThread::popframe_preserved_args() {
3103 return _popframe_preserved_args;
3104 }
3105
3106 ByteSize JavaThread::popframe_preserved_args_size() {
3107 return in_ByteSize(_popframe_preserved_args_size);
3108 }
3109
3110 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3111 int sz = in_bytes(popframe_preserved_args_size());
3112 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3113 return in_WordSize(sz / wordSize);
3114 }
3115
3116 void JavaThread::popframe_free_preserved_args() {
3117 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3118 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3119 _popframe_preserved_args = NULL;
3120 _popframe_preserved_args_size = 0;
3121 }
3122
3123 #ifndef PRODUCT
3124
3125 void JavaThread::trace_frames() {
3126 tty->print_cr("[Describe stack]");
3127 int frame_no = 1;
3128 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3129 tty->print(" %d. ", frame_no++);
3130 fst.current()->print_value_on(tty,this);
3131 tty->cr();
3132 }
3133 }
3134
3135 class PrintAndVerifyOopClosure: public OopClosure {
3136 protected:
3137 template <class T> inline void do_oop_work(T* p) {
3138 oop obj = oopDesc::load_decode_heap_oop(p);
3139 if (obj == NULL) return;
3140 tty->print(INTPTR_FORMAT ": ", p);
3141 if (obj->is_oop_or_null()) {
3142 if (obj->is_objArray()) {
3143 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3144 } else {
3145 obj->print();
3146 }
3147 } else {
3148 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3149 }
3150 tty->cr();
3151 }
3152 public:
3153 virtual void do_oop(oop* p) { do_oop_work(p); }
3154 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3155 };
3156
3157
3158 static void oops_print(frame* f, const RegisterMap *map) {
3159 PrintAndVerifyOopClosure print;
3160 f->print_value();
3161 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3162 }
3163
3164 // Print our all the locations that contain oops and whether they are
3165 // valid or not. This useful when trying to find the oldest frame
3166 // where an oop has gone bad since the frame walk is from youngest to
3167 // oldest.
3168 void JavaThread::trace_oops() {
3169 tty->print_cr("[Trace oops]");
3170 frames_do(oops_print);
3171 }
3172
3173
3174 #ifdef ASSERT
3175 // Print or validate the layout of stack frames
3176 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3177 ResourceMark rm;
3178 PRESERVE_EXCEPTION_MARK;
3179 FrameValues values;
3180 int frame_no = 0;
3181 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3182 fst.current()->describe(values, ++frame_no);
3183 if (depth == frame_no) break;
3184 }
3185 if (validate_only) {
3186 values.validate();
3187 } else {
3188 tty->print_cr("[Describe stack layout]");
3189 values.print(this);
3190 }
3191 }
3192 #endif
3193
3194 void JavaThread::trace_stack_from(vframe* start_vf) {
3195 ResourceMark rm;
3196 int vframe_no = 1;
3197 for (vframe* f = start_vf; f; f = f->sender() ) {
3198 if (f->is_java_frame()) {
3199 javaVFrame::cast(f)->print_activation(vframe_no++);
3200 } else {
3201 f->print();
3202 }
3203 if (vframe_no > StackPrintLimit) {
3204 tty->print_cr("...<more frames>...");
3205 return;
3206 }
3207 }
3208 }
3209
3210
3211 void JavaThread::trace_stack() {
3212 if (!has_last_Java_frame()) return;
3213 ResourceMark rm;
3214 HandleMark hm;
3215 RegisterMap reg_map(this);
3216 trace_stack_from(last_java_vframe(®_map));
3217 }
3218
3219
3220 #endif // PRODUCT
3221
3222
3223 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3224 assert(reg_map != NULL, "a map must be given");
3225 frame f = last_frame();
3226 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3227 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3228 }
3229 return NULL;
3230 }
3231
3232
3233 Klass* JavaThread::security_get_caller_class(int depth) {
3234 vframeStream vfst(this);
3235 vfst.security_get_caller_frame(depth);
3236 if (!vfst.at_end()) {
3237 return vfst.method()->method_holder();
3238 }
3239 return NULL;
3240 }
3241
3242 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3243 assert(thread->is_Compiler_thread(), "must be compiler thread");
3244 CompileBroker::compiler_thread_loop();
3245 }
3246
3247 // Create a CompilerThread
3248 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3249 : JavaThread(&compiler_thread_entry) {
3250 _env = NULL;
3251 _log = NULL;
3252 _task = NULL;
3253 _queue = queue;
3254 _counters = counters;
3255 _buffer_blob = NULL;
3256 _scanned_nmethod = NULL;
3257 _compiler = NULL;
3258
3259 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3260 resource_area()->bias_to(mtCompiler);
3261
3262 #ifndef PRODUCT
3263 _ideal_graph_printer = NULL;
3264 #endif
3265 }
3266
3267 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3268 JavaThread::oops_do(f, cld_f, cf);
3269 if (_scanned_nmethod != NULL && cf != NULL) {
3270 // Safepoints can occur when the sweeper is scanning an nmethod so
3271 // process it here to make sure it isn't unloaded in the middle of
3272 // a scan.
3273 cf->do_code_blob(_scanned_nmethod);
3274 }
3275 }
3276
3277
3278 // ======= Threads ========
3279
3280 // The Threads class links together all active threads, and provides
3281 // operations over all threads. It is protected by its own Mutex
3282 // lock, which is also used in other contexts to protect thread
3283 // operations from having the thread being operated on from exiting
3284 // and going away unexpectedly (e.g., safepoint synchronization)
3285
3286 JavaThread* Threads::_thread_list = NULL;
3287 int Threads::_number_of_threads = 0;
3288 int Threads::_number_of_non_daemon_threads = 0;
3289 int Threads::_return_code = 0;
3290 size_t JavaThread::_stack_size_at_create = 0;
3291 #ifdef ASSERT
3292 bool Threads::_vm_complete = false;
3293 #endif
3294
3295 // All JavaThreads
3296 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3297
3298 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3299 void Threads::threads_do(ThreadClosure* tc) {
3300 assert_locked_or_safepoint(Threads_lock);
3301 // ALL_JAVA_THREADS iterates through all JavaThreads
3302 ALL_JAVA_THREADS(p) {
3303 tc->do_thread(p);
3304 }
3305 // Someday we could have a table or list of all non-JavaThreads.
3306 // For now, just manually iterate through them.
3307 tc->do_thread(VMThread::vm_thread());
3308 Universe::heap()->gc_threads_do(tc);
3309 WatcherThread *wt = WatcherThread::watcher_thread();
3310 // Strictly speaking, the following NULL check isn't sufficient to make sure
3311 // the data for WatcherThread is still valid upon being examined. However,
3312 // considering that WatchThread terminates when the VM is on the way to
3313 // exit at safepoint, the chance of the above is extremely small. The right
3314 // way to prevent termination of WatcherThread would be to acquire
3315 // Terminator_lock, but we can't do that without violating the lock rank
3316 // checking in some cases.
3317 if (wt != NULL)
3318 tc->do_thread(wt);
3319
3320 // If CompilerThreads ever become non-JavaThreads, add them here
3321 }
3322
3323 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3324
3325 extern void JDK_Version_init();
3326
3327 // Preinitialize version info.
3328 VM_Version::early_initialize();
3329
3330 // Check version
3331 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3332
3333 // Initialize the output stream module
3334 ostream_init();
3335
3336 // Process java launcher properties.
3337 Arguments::process_sun_java_launcher_properties(args);
3338
3339 // Initialize the os module before using TLS
3340 os::init();
3341
3342 // Initialize system properties.
3343 Arguments::init_system_properties();
3344
3345 // So that JDK version can be used as a discrimintor when parsing arguments
3346 JDK_Version_init();
3347
3348 // Update/Initialize System properties after JDK version number is known
3349 Arguments::init_version_specific_system_properties();
3350
3351 // Parse arguments
3352 // Note: this internally calls os::init_container_support()
3353 jint parse_result = Arguments::parse(args);
3354 if (parse_result != JNI_OK) return parse_result;
3355
3356 os::init_before_ergo();
3357
3358 jint ergo_result = Arguments::apply_ergo();
3359 if (ergo_result != JNI_OK) return ergo_result;
3360
3361 if (PauseAtStartup) {
3362 os::pause();
3363 }
3364
3365 #ifndef USDT2
3366 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3367 #else /* USDT2 */
3368 HOTSPOT_VM_INIT_BEGIN();
3369 #endif /* USDT2 */
3370
3371 // Record VM creation timing statistics
3372 TraceVmCreationTime create_vm_timer;
3373 create_vm_timer.start();
3374
3375 // Timing (must come after argument parsing)
3376 TraceTime timer("Create VM", TraceStartupTime);
3377
3378 // Initialize the os module after parsing the args
3379 jint os_init_2_result = os::init_2();
3380 if (os_init_2_result != JNI_OK) return os_init_2_result;
3381
3382 jint adjust_after_os_result = Arguments::adjust_after_os();
3383 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3384
3385 // intialize TLS
3386 ThreadLocalStorage::init();
3387
3388 // Initialize output stream logging
3389 ostream_init_log();
3390
3391 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3392 // Must be before create_vm_init_agents()
3393 if (Arguments::init_libraries_at_startup()) {
3394 convert_vm_init_libraries_to_agents();
3395 }
3396
3397 // Launch -agentlib/-agentpath and converted -Xrun agents
3398 if (Arguments::init_agents_at_startup()) {
3399 create_vm_init_agents();
3400 }
3401
3402 // Initialize Threads state
3403 _thread_list = NULL;
3404 _number_of_threads = 0;
3405 _number_of_non_daemon_threads = 0;
3406
3407 // Initialize global data structures and create system classes in heap
3408 vm_init_globals();
3409
3410 // Attach the main thread to this os thread
3411 JavaThread* main_thread = new JavaThread();
3412 main_thread->set_thread_state(_thread_in_vm);
3413 // must do this before set_active_handles and initialize_thread_local_storage
3414 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3415 // change the stack size recorded here to one based on the java thread
3416 // stacksize. This adjusted size is what is used to figure the placement
3417 // of the guard pages.
3418 main_thread->record_stack_base_and_size();
3419 main_thread->initialize_thread_local_storage();
3420
3421 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3422
3423 if (!main_thread->set_as_starting_thread()) {
3424 vm_shutdown_during_initialization(
3425 "Failed necessary internal allocation. Out of swap space");
3426 delete main_thread;
3427 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3428 return JNI_ENOMEM;
3429 }
3430
3431 // Enable guard page *after* os::create_main_thread(), otherwise it would
3432 // crash Linux VM, see notes in os_linux.cpp.
3433 main_thread->create_stack_guard_pages();
3434
3435 // Initialize Java-Level synchronization subsystem
3436 ObjectMonitor::Initialize() ;
3437
3438 // Initialize global modules
3439 jint status = init_globals();
3440 if (status != JNI_OK) {
3441 delete main_thread;
3442 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3443 return status;
3444 }
3445
3446 // Should be done after the heap is fully created
3447 main_thread->cache_global_variables();
3448
3449 HandleMark hm;
3450
3451 { MutexLocker mu(Threads_lock);
3452 Threads::add(main_thread);
3453 }
3454
3455 // Any JVMTI raw monitors entered in onload will transition into
3456 // real raw monitor. VM is setup enough here for raw monitor enter.
3457 JvmtiExport::transition_pending_onload_raw_monitors();
3458
3459 // Create the VMThread
3460 { TraceTime timer("Start VMThread", TraceStartupTime);
3461 VMThread::create();
3462 Thread* vmthread = VMThread::vm_thread();
3463
3464 if (!os::create_thread(vmthread, os::vm_thread))
3465 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3466
3467 // Wait for the VM thread to become ready, and VMThread::run to initialize
3468 // Monitors can have spurious returns, must always check another state flag
3469 {
3470 MutexLocker ml(Notify_lock);
3471 os::start_thread(vmthread);
3472 while (vmthread->active_handles() == NULL) {
3473 Notify_lock->wait();
3474 }
3475 }
3476 }
3477
3478 assert (Universe::is_fully_initialized(), "not initialized");
3479 if (VerifyDuringStartup) {
3480 // Make sure we're starting with a clean slate.
3481 VM_Verify verify_op;
3482 VMThread::execute(&verify_op);
3483 }
3484
3485 EXCEPTION_MARK;
3486
3487 // At this point, the Universe is initialized, but we have not executed
3488 // any byte code. Now is a good time (the only time) to dump out the
3489 // internal state of the JVM for sharing.
3490 if (DumpSharedSpaces) {
3491 MetaspaceShared::preload_and_dump(CHECK_0);
3492 ShouldNotReachHere();
3493 }
3494
3495 // Always call even when there are not JVMTI environments yet, since environments
3496 // may be attached late and JVMTI must track phases of VM execution
3497 JvmtiExport::enter_start_phase();
3498
3499 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3500 JvmtiExport::post_vm_start();
3501
3502 {
3503 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3504
3505 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3506 create_vm_init_libraries();
3507 }
3508
3509 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3510
3511 // Initialize java_lang.System (needed before creating the thread)
3512 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3513 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3514 Handle thread_group = create_initial_thread_group(CHECK_0);
3515 Universe::set_main_thread_group(thread_group());
3516 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3517 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3518 main_thread->set_threadObj(thread_object);
3519 // Set thread status to running since main thread has
3520 // been started and running.
3521 java_lang_Thread::set_thread_status(thread_object,
3522 java_lang_Thread::RUNNABLE);
3523
3524 // The VM creates & returns objects of this class. Make sure it's initialized.
3525 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3526
3527 // The VM preresolves methods to these classes. Make sure that they get initialized
3528 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3529 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3530 call_initializeSystemClass(CHECK_0);
3531
3532 // get the Java runtime name after java.lang.System is initialized
3533 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3534 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3535
3536 // an instance of OutOfMemory exception has been allocated earlier
3537 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3538 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3539 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3540 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3541 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3542 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3543 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3544 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3545 }
3546
3547 // See : bugid 4211085.
3548 // Background : the static initializer of java.lang.Compiler tries to read
3549 // property"java.compiler" and read & write property "java.vm.info".
3550 // When a security manager is installed through the command line
3551 // option "-Djava.security.manager", the above properties are not
3552 // readable and the static initializer for java.lang.Compiler fails
3553 // resulting in a NoClassDefFoundError. This can happen in any
3554 // user code which calls methods in java.lang.Compiler.
3555 // Hack : the hack is to pre-load and initialize this class, so that only
3556 // system domains are on the stack when the properties are read.
3557 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3558 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3559 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3560 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3561 // Once that is done, we should remove this hack.
3562 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3563
3564 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3565 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3566 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3567 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3568 // This should also be taken out as soon as 4211383 gets fixed.
3569 reset_vm_info_property(CHECK_0);
3570
3571 quicken_jni_functions();
3572
3573 // Must be run after init_ft which initializes ft_enabled
3574 if (TRACE_INITIALIZE() != JNI_OK) {
3575 vm_exit_during_initialization("Failed to initialize tracing backend");
3576 }
3577
3578 // Set flag that basic initialization has completed. Used by exceptions and various
3579 // debug stuff, that does not work until all basic classes have been initialized.
3580 set_init_completed();
3581
3582 Metaspace::post_initialize();
3583
3584 #ifndef USDT2
3585 HS_DTRACE_PROBE(hotspot, vm__init__end);
3586 #else /* USDT2 */
3587 HOTSPOT_VM_INIT_END();
3588 #endif /* USDT2 */
3589
3590 // record VM initialization completion time
3591 #if INCLUDE_MANAGEMENT
3592 Management::record_vm_init_completed();
3593 #endif // INCLUDE_MANAGEMENT
3594
3595 // Compute system loader. Note that this has to occur after set_init_completed, since
3596 // valid exceptions may be thrown in the process.
3597 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3598 // set_init_completed has just been called, causing exceptions not to be shortcut
3599 // anymore. We call vm_exit_during_initialization directly instead.
3600 SystemDictionary::compute_java_system_loader(THREAD);
3601 if (HAS_PENDING_EXCEPTION) {
3602 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3603 }
3604
3605 #if INCLUDE_ALL_GCS
3606 // Support for ConcurrentMarkSweep. This should be cleaned up
3607 // and better encapsulated. The ugly nested if test would go away
3608 // once things are properly refactored. XXX YSR
3609 if (UseConcMarkSweepGC || UseG1GC) {
3610 if (UseConcMarkSweepGC) {
3611 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3612 } else {
3613 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3614 }
3615 if (HAS_PENDING_EXCEPTION) {
3616 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3617 }
3618 }
3619 #endif // INCLUDE_ALL_GCS
3620
3621 // Always call even when there are not JVMTI environments yet, since environments
3622 // may be attached late and JVMTI must track phases of VM execution
3623 JvmtiExport::enter_live_phase();
3624
3625 // Signal Dispatcher needs to be started before VMInit event is posted
3626 os::signal_init();
3627
3628 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3629 if (!DisableAttachMechanism) {
3630 AttachListener::vm_start();
3631 if (StartAttachListener || AttachListener::init_at_startup()) {
3632 AttachListener::init();
3633 }
3634 }
3635
3636 // Launch -Xrun agents
3637 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3638 // back-end can launch with -Xdebug -Xrunjdwp.
3639 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3640 create_vm_init_libraries();
3641 }
3642
3643 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3644 JvmtiExport::post_vm_initialized();
3645
3646 if (TRACE_START() != JNI_OK) {
3647 vm_exit_during_initialization("Failed to start tracing backend.");
3648 }
3649
3650 if (CleanChunkPoolAsync) {
3651 Chunk::start_chunk_pool_cleaner_task();
3652 }
3653
3654 // initialize compiler(s)
3655 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3656 CompileBroker::compilation_init();
3657 #endif
3658
3659 if (EnableInvokeDynamic) {
3660 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3661 // It is done after compilers are initialized, because otherwise compilations of
3662 // signature polymorphic MH intrinsics can be missed
3663 // (see SystemDictionary::find_method_handle_intrinsic).
3664 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3665 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3666 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3667 }
3668
3669 // See : bugid 8194653
3670 // Background : Deadlock as described by https://bugs.openjdk.java.net/browse/JDK-8194653
3671 // Mitigation : Eliminates a race condition on call to
3672 // java.nio.file.FileSystems::getDefault() where two threads (one inside
3673 // a loadLibrary() call) could cause a deadlock if they both referenced this
3674 // code path. Priming the code path during startup eliminates the deadlock
3675 // (<clinit> and loadLibrary0 are single threaded).
3676 // Note the JVM is at the end of initialization and the getDefault() call
3677 // is safe to make.
3678 // Future Fix : OpenJDK 9 beyond address the issue with a different (fixed) startup
3679 // sequence. For OpenJDK 8 this should be sufficient.
3680 {
3681 Klass* k = initialize_class_and_return(vmSymbols::java_nio_file_FileSystems(), CHECK_0);
3682 instanceKlassHandle klass (THREAD, k);
3683 JavaValue result(T_OBJECT);
3684
3685 JavaCalls::call_static(&result, klass, vmSymbols::getDefault_name(),
3686 vmSymbols::getDefault_signature(), CHECK_0);
3687 }
3688
3689 #if INCLUDE_MANAGEMENT
3690 Management::initialize(THREAD);
3691 #endif // INCLUDE_MANAGEMENT
3692
3693 if (HAS_PENDING_EXCEPTION) {
3694 // management agent fails to start possibly due to
3695 // configuration problem and is responsible for printing
3696 // stack trace if appropriate. Simply exit VM.
3697 vm_exit(1);
3698 }
3699
3700 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3701 if (MemProfiling) MemProfiler::engage();
3702 StatSampler::engage();
3703 if (CheckJNICalls) JniPeriodicChecker::engage();
3704
3705 BiasedLocking::init();
3706
3707 #if INCLUDE_RTM_OPT
3708 RTMLockingCounters::init();
3709 #endif
3710
3711 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3712 call_postVMInitHook(THREAD);
3713 // The Java side of PostVMInitHook.run must deal with all
3714 // exceptions and provide means of diagnosis.
3715 if (HAS_PENDING_EXCEPTION) {
3716 CLEAR_PENDING_EXCEPTION;
3717 }
3718 }
3719
3720 {
3721 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3722 // Make sure the watcher thread can be started by WatcherThread::start()
3723 // or by dynamic enrollment.
3724 WatcherThread::make_startable();
3725 // Start up the WatcherThread if there are any periodic tasks
3726 // NOTE: All PeriodicTasks should be registered by now. If they
3727 // aren't, late joiners might appear to start slowly (we might
3728 // take a while to process their first tick).
3729 if (PeriodicTask::num_tasks() > 0) {
3730 WatcherThread::start();
3731 }
3732 }
3733
3734 create_vm_timer.end();
3735 #ifdef ASSERT
3736 _vm_complete = true;
3737 #endif
3738 return JNI_OK;
3739 }
3740
3741 // type for the Agent_OnLoad and JVM_OnLoad entry points
3742 extern "C" {
3743 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3744 }
3745 // Find a command line agent library and return its entry point for
3746 // -agentlib: -agentpath: -Xrun
3747 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3748 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3749 OnLoadEntry_t on_load_entry = NULL;
3750 void *library = NULL;
3751
3752 if (!agent->valid()) {
3753 char buffer[JVM_MAXPATHLEN];
3754 char ebuf[1024];
3755 const char *name = agent->name();
3756 const char *msg = "Could not find agent library ";
3757
3758 // First check to see if agent is statically linked into executable
3759 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3760 library = agent->os_lib();
3761 } else if (agent->is_absolute_path()) {
3762 library = os::dll_load(name, ebuf, sizeof ebuf);
3763 if (library == NULL) {
3764 const char *sub_msg = " in absolute path, with error: ";
3765 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3766 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3767 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3768 // If we can't find the agent, exit.
3769 vm_exit_during_initialization(buf, NULL);
3770 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3771 }
3772 } else {
3773 // Try to load the agent from the standard dll directory
3774 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3775 name)) {
3776 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3777 }
3778 if (library == NULL) { // Try the local directory
3779 char ns[1] = {0};
3780 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3781 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3782 }
3783 if (library == NULL) {
3784 const char *sub_msg = " on the library path, with error: ";
3785 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3786 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3787 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3788 // If we can't find the agent, exit.
3789 vm_exit_during_initialization(buf, NULL);
3790 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3791 }
3792 }
3793 }
3794 agent->set_os_lib(library);
3795 agent->set_valid();
3796 }
3797
3798 // Find the OnLoad function.
3799 on_load_entry =
3800 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3801 false,
3802 on_load_symbols,
3803 num_symbol_entries));
3804 return on_load_entry;
3805 }
3806
3807 // Find the JVM_OnLoad entry point
3808 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3809 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3810 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3811 }
3812
3813 // Find the Agent_OnLoad entry point
3814 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3815 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3816 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3817 }
3818
3819 // For backwards compatibility with -Xrun
3820 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3821 // treated like -agentpath:
3822 // Must be called before agent libraries are created
3823 void Threads::convert_vm_init_libraries_to_agents() {
3824 AgentLibrary* agent;
3825 AgentLibrary* next;
3826
3827 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3828 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3829 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3830
3831 // If there is an JVM_OnLoad function it will get called later,
3832 // otherwise see if there is an Agent_OnLoad
3833 if (on_load_entry == NULL) {
3834 on_load_entry = lookup_agent_on_load(agent);
3835 if (on_load_entry != NULL) {
3836 // switch it to the agent list -- so that Agent_OnLoad will be called,
3837 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3838 Arguments::convert_library_to_agent(agent);
3839 } else {
3840 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3841 }
3842 }
3843 }
3844 }
3845
3846 // Create agents for -agentlib: -agentpath: and converted -Xrun
3847 // Invokes Agent_OnLoad
3848 // Called very early -- before JavaThreads exist
3849 void Threads::create_vm_init_agents() {
3850 extern struct JavaVM_ main_vm;
3851 AgentLibrary* agent;
3852
3853 JvmtiExport::enter_onload_phase();
3854
3855 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3856 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3857
3858 if (on_load_entry != NULL) {
3859 // Invoke the Agent_OnLoad function
3860 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3861 if (err != JNI_OK) {
3862 vm_exit_during_initialization("agent library failed to init", agent->name());
3863 }
3864 } else {
3865 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3866 }
3867 }
3868 JvmtiExport::enter_primordial_phase();
3869 }
3870
3871 extern "C" {
3872 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3873 }
3874
3875 void Threads::shutdown_vm_agents() {
3876 // Send any Agent_OnUnload notifications
3877 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3878 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3879 extern struct JavaVM_ main_vm;
3880 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3881
3882 // Find the Agent_OnUnload function.
3883 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3884 os::find_agent_function(agent,
3885 false,
3886 on_unload_symbols,
3887 num_symbol_entries));
3888
3889 // Invoke the Agent_OnUnload function
3890 if (unload_entry != NULL) {
3891 JavaThread* thread = JavaThread::current();
3892 ThreadToNativeFromVM ttn(thread);
3893 HandleMark hm(thread);
3894 (*unload_entry)(&main_vm);
3895 }
3896 }
3897 }
3898
3899 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3900 // Invokes JVM_OnLoad
3901 void Threads::create_vm_init_libraries() {
3902 extern struct JavaVM_ main_vm;
3903 AgentLibrary* agent;
3904
3905 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3906 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3907
3908 if (on_load_entry != NULL) {
3909 // Invoke the JVM_OnLoad function
3910 JavaThread* thread = JavaThread::current();
3911 ThreadToNativeFromVM ttn(thread);
3912 HandleMark hm(thread);
3913 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3914 if (err != JNI_OK) {
3915 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3916 }
3917 } else {
3918 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3919 }
3920 }
3921 }
3922
3923 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3924 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3925
3926 JavaThread* java_thread = NULL;
3927 // Sequential search for now. Need to do better optimization later.
3928 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3929 oop tobj = thread->threadObj();
3930 if (!thread->is_exiting() &&
3931 tobj != NULL &&
3932 java_tid == java_lang_Thread::thread_id(tobj)) {
3933 java_thread = thread;
3934 break;
3935 }
3936 }
3937 return java_thread;
3938 }
3939
3940
3941 // Last thread running calls java.lang.Shutdown.shutdown()
3942 void JavaThread::invoke_shutdown_hooks() {
3943 HandleMark hm(this);
3944
3945 // We could get here with a pending exception, if so clear it now.
3946 if (this->has_pending_exception()) {
3947 this->clear_pending_exception();
3948 }
3949
3950 EXCEPTION_MARK;
3951 Klass* k =
3952 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3953 THREAD);
3954 if (k != NULL) {
3955 // SystemDictionary::resolve_or_null will return null if there was
3956 // an exception. If we cannot load the Shutdown class, just don't
3957 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3958 // and finalizers (if runFinalizersOnExit is set) won't be run.
3959 // Note that if a shutdown hook was registered or runFinalizersOnExit
3960 // was called, the Shutdown class would have already been loaded
3961 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3962 instanceKlassHandle shutdown_klass (THREAD, k);
3963 JavaValue result(T_VOID);
3964 JavaCalls::call_static(&result,
3965 shutdown_klass,
3966 vmSymbols::shutdown_method_name(),
3967 vmSymbols::void_method_signature(),
3968 THREAD);
3969 }
3970 CLEAR_PENDING_EXCEPTION;
3971 }
3972
3973 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3974 // the program falls off the end of main(). Another VM exit path is through
3975 // vm_exit() when the program calls System.exit() to return a value or when
3976 // there is a serious error in VM. The two shutdown paths are not exactly
3977 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3978 // and VM_Exit op at VM level.
3979 //
3980 // Shutdown sequence:
3981 // + Shutdown native memory tracking if it is on
3982 // + Wait until we are the last non-daemon thread to execute
3983 // <-- every thing is still working at this moment -->
3984 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3985 // shutdown hooks, run finalizers if finalization-on-exit
3986 // + Call before_exit(), prepare for VM exit
3987 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3988 // currently the only user of this mechanism is File.deleteOnExit())
3989 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3990 // post thread end and vm death events to JVMTI,
3991 // stop signal thread
3992 // + Call JavaThread::exit(), it will:
3993 // > release JNI handle blocks, remove stack guard pages
3994 // > remove this thread from Threads list
3995 // <-- no more Java code from this thread after this point -->
3996 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3997 // the compiler threads at safepoint
3998 // <-- do not use anything that could get blocked by Safepoint -->
3999 // + Disable tracing at JNI/JVM barriers
4000 // + Set _vm_exited flag for threads that are still running native code
4001 // + Delete this thread
4002 // + Call exit_globals()
4003 // > deletes tty
4004 // > deletes PerfMemory resources
4005 // + Return to caller
4006
4007 bool Threads::destroy_vm() {
4008 JavaThread* thread = JavaThread::current();
4009
4010 #ifdef ASSERT
4011 _vm_complete = false;
4012 #endif
4013 // Wait until we are the last non-daemon thread to execute
4014 { MutexLocker nu(Threads_lock);
4015 while (Threads::number_of_non_daemon_threads() > 1 )
4016 // This wait should make safepoint checks, wait without a timeout,
4017 // and wait as a suspend-equivalent condition.
4018 //
4019 // Note: If the FlatProfiler is running and this thread is waiting
4020 // for another non-daemon thread to finish, then the FlatProfiler
4021 // is waiting for the external suspend request on this thread to
4022 // complete. wait_for_ext_suspend_completion() will eventually
4023 // timeout, but that takes time. Making this wait a suspend-
4024 // equivalent condition solves that timeout problem.
4025 //
4026 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4027 Mutex::_as_suspend_equivalent_flag);
4028 }
4029
4030 // Hang forever on exit if we are reporting an error.
4031 if (ShowMessageBoxOnError && is_error_reported()) {
4032 os::infinite_sleep();
4033 }
4034 os::wait_for_keypress_at_exit();
4035
4036 if (JDK_Version::is_jdk12x_version()) {
4037 // We are the last thread running, so check if finalizers should be run.
4038 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
4039 HandleMark rm(thread);
4040 Universe::run_finalizers_on_exit();
4041 } else {
4042 // run Java level shutdown hooks
4043 thread->invoke_shutdown_hooks();
4044 }
4045
4046 before_exit(thread);
4047
4048 thread->exit(true);
4049
4050 // Stop VM thread.
4051 {
4052 // 4945125 The vm thread comes to a safepoint during exit.
4053 // GC vm_operations can get caught at the safepoint, and the
4054 // heap is unparseable if they are caught. Grab the Heap_lock
4055 // to prevent this. The GC vm_operations will not be able to
4056 // queue until after the vm thread is dead. After this point,
4057 // we'll never emerge out of the safepoint before the VM exits.
4058
4059 MutexLocker ml(Heap_lock);
4060
4061 VMThread::wait_for_vm_thread_exit();
4062 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4063 VMThread::destroy();
4064 }
4065
4066 // clean up ideal graph printers
4067 #if defined(COMPILER2) && !defined(PRODUCT)
4068 IdealGraphPrinter::clean_up();
4069 #endif
4070
4071 // Now, all Java threads are gone except daemon threads. Daemon threads
4072 // running Java code or in VM are stopped by the Safepoint. However,
4073 // daemon threads executing native code are still running. But they
4074 // will be stopped at native=>Java/VM barriers. Note that we can't
4075 // simply kill or suspend them, as it is inherently deadlock-prone.
4076
4077 #ifndef PRODUCT
4078 // disable function tracing at JNI/JVM barriers
4079 TraceJNICalls = false;
4080 TraceJVMCalls = false;
4081 TraceRuntimeCalls = false;
4082 #endif
4083
4084 VM_Exit::set_vm_exited();
4085
4086 notify_vm_shutdown();
4087
4088 delete thread;
4089
4090 // exit_globals() will delete tty
4091 exit_globals();
4092
4093 return true;
4094 }
4095
4096
4097 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4098 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4099 return is_supported_jni_version(version);
4100 }
4101
4102
4103 jboolean Threads::is_supported_jni_version(jint version) {
4104 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4105 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4106 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4107 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4108 return JNI_FALSE;
4109 }
4110
4111
4112 void Threads::add(JavaThread* p, bool force_daemon) {
4113 // The threads lock must be owned at this point
4114 assert_locked_or_safepoint(Threads_lock);
4115
4116 // See the comment for this method in thread.hpp for its purpose and
4117 // why it is called here.
4118 p->initialize_queues();
4119 p->set_next(_thread_list);
4120 _thread_list = p;
4121 _number_of_threads++;
4122 oop threadObj = p->threadObj();
4123 bool daemon = true;
4124 // Bootstrapping problem: threadObj can be null for initial
4125 // JavaThread (or for threads attached via JNI)
4126 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4127 _number_of_non_daemon_threads++;
4128 daemon = false;
4129 }
4130
4131 ThreadService::add_thread(p, daemon);
4132
4133 // Possible GC point.
4134 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4135 }
4136
4137 void Threads::remove(JavaThread* p) {
4138 // Extra scope needed for Thread_lock, so we can check
4139 // that we do not remove thread without safepoint code notice
4140 { MutexLocker ml(Threads_lock);
4141
4142 assert(includes(p), "p must be present");
4143
4144 JavaThread* current = _thread_list;
4145 JavaThread* prev = NULL;
4146
4147 while (current != p) {
4148 prev = current;
4149 current = current->next();
4150 }
4151
4152 if (prev) {
4153 prev->set_next(current->next());
4154 } else {
4155 _thread_list = p->next();
4156 }
4157 _number_of_threads--;
4158 oop threadObj = p->threadObj();
4159 bool daemon = true;
4160 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4161 _number_of_non_daemon_threads--;
4162 daemon = false;
4163
4164 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4165 // on destroy_vm will wake up.
4166 if (number_of_non_daemon_threads() == 1)
4167 Threads_lock->notify_all();
4168 }
4169 ThreadService::remove_thread(p, daemon);
4170
4171 // Make sure that safepoint code disregard this thread. This is needed since
4172 // the thread might mess around with locks after this point. This can cause it
4173 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4174 // of this thread since it is removed from the queue.
4175 p->set_terminated_value();
4176 } // unlock Threads_lock
4177
4178 // Since Events::log uses a lock, we grab it outside the Threads_lock
4179 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4180 }
4181
4182 // Threads_lock must be held when this is called (or must be called during a safepoint)
4183 bool Threads::includes(JavaThread* p) {
4184 assert(Threads_lock->is_locked(), "sanity check");
4185 ALL_JAVA_THREADS(q) {
4186 if (q == p ) {
4187 return true;
4188 }
4189 }
4190 return false;
4191 }
4192
4193 // Operations on the Threads list for GC. These are not explicitly locked,
4194 // but the garbage collector must provide a safe context for them to run.
4195 // In particular, these things should never be called when the Threads_lock
4196 // is held by some other thread. (Note: the Safepoint abstraction also
4197 // uses the Threads_lock to gurantee this property. It also makes sure that
4198 // all threads gets blocked when exiting or starting).
4199
4200 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4201 ALL_JAVA_THREADS(p) {
4202 p->oops_do(f, cld_f, cf);
4203 }
4204 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4205 }
4206
4207 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4208 // Introduce a mechanism allowing parallel threads to claim threads as
4209 // root groups. Overhead should be small enough to use all the time,
4210 // even in sequential code.
4211 SharedHeap* sh = SharedHeap::heap();
4212 // Cannot yet substitute active_workers for n_par_threads
4213 // because of G1CollectedHeap::verify() use of
4214 // SharedHeap::process_roots(). n_par_threads == 0 will
4215 // turn off parallelism in process_roots while active_workers
4216 // is being used for parallelism elsewhere.
4217 bool is_par = sh->n_par_threads() > 0;
4218 assert(!is_par ||
4219 (SharedHeap::heap()->n_par_threads() ==
4220 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4221 int cp = SharedHeap::heap()->strong_roots_parity();
4222 ALL_JAVA_THREADS(p) {
4223 if (p->claim_oops_do(is_par, cp)) {
4224 p->oops_do(f, cld_f, cf);
4225 }
4226 }
4227 VMThread* vmt = VMThread::vm_thread();
4228 if (vmt->claim_oops_do(is_par, cp)) {
4229 vmt->oops_do(f, cld_f, cf);
4230 }
4231 }
4232
4233 #if INCLUDE_ALL_GCS
4234 // Used by ParallelScavenge
4235 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4236 ALL_JAVA_THREADS(p) {
4237 q->enqueue(new ThreadRootsTask(p));
4238 }
4239 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4240 }
4241
4242 // Used by Parallel Old
4243 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4244 ALL_JAVA_THREADS(p) {
4245 q->enqueue(new ThreadRootsMarkingTask(p));
4246 }
4247 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4248 }
4249 #endif // INCLUDE_ALL_GCS
4250
4251 void Threads::nmethods_do(CodeBlobClosure* cf) {
4252 ALL_JAVA_THREADS(p) {
4253 p->nmethods_do(cf);
4254 }
4255 VMThread::vm_thread()->nmethods_do(cf);
4256 }
4257
4258 void Threads::metadata_do(void f(Metadata*)) {
4259 ALL_JAVA_THREADS(p) {
4260 p->metadata_do(f);
4261 }
4262 }
4263
4264 void Threads::gc_epilogue() {
4265 ALL_JAVA_THREADS(p) {
4266 p->gc_epilogue();
4267 }
4268 }
4269
4270 void Threads::gc_prologue() {
4271 ALL_JAVA_THREADS(p) {
4272 p->gc_prologue();
4273 }
4274 }
4275
4276 void Threads::deoptimized_wrt_marked_nmethods() {
4277 ALL_JAVA_THREADS(p) {
4278 p->deoptimized_wrt_marked_nmethods();
4279 }
4280 }
4281
4282
4283 // Get count Java threads that are waiting to enter the specified monitor.
4284 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4285 address monitor, bool doLock) {
4286 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4287 "must grab Threads_lock or be at safepoint");
4288 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4289
4290 int i = 0;
4291 {
4292 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4293 ALL_JAVA_THREADS(p) {
4294 if (p->is_Compiler_thread()) continue;
4295
4296 address pending = (address)p->current_pending_monitor();
4297 if (pending == monitor) { // found a match
4298 if (i < count) result->append(p); // save the first count matches
4299 i++;
4300 }
4301 }
4302 }
4303 return result;
4304 }
4305
4306
4307 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4308 assert(doLock ||
4309 Threads_lock->owned_by_self() ||
4310 SafepointSynchronize::is_at_safepoint(),
4311 "must grab Threads_lock or be at safepoint");
4312
4313 // NULL owner means not locked so we can skip the search
4314 if (owner == NULL) return NULL;
4315
4316 {
4317 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4318 ALL_JAVA_THREADS(p) {
4319 // first, see if owner is the address of a Java thread
4320 if (owner == (address)p) return p;
4321 }
4322 }
4323 // Cannot assert on lack of success here since this function may be
4324 // used by code that is trying to report useful problem information
4325 // like deadlock detection.
4326 if (UseHeavyMonitors) return NULL;
4327
4328 //
4329 // If we didn't find a matching Java thread and we didn't force use of
4330 // heavyweight monitors, then the owner is the stack address of the
4331 // Lock Word in the owning Java thread's stack.
4332 //
4333 JavaThread* the_owner = NULL;
4334 {
4335 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4336 ALL_JAVA_THREADS(q) {
4337 if (q->is_lock_owned(owner)) {
4338 the_owner = q;
4339 break;
4340 }
4341 }
4342 }
4343 // cannot assert on lack of success here; see above comment
4344 return the_owner;
4345 }
4346
4347 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4348 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4349 char buf[32];
4350 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4351
4352 st->print_cr("Full thread dump %s (%s %s):",
4353 Abstract_VM_Version::vm_name(),
4354 Abstract_VM_Version::vm_release(),
4355 Abstract_VM_Version::vm_info_string()
4356 );
4357 st->cr();
4358
4359 #if INCLUDE_ALL_GCS
4360 // Dump concurrent locks
4361 ConcurrentLocksDump concurrent_locks;
4362 if (print_concurrent_locks) {
4363 concurrent_locks.dump_at_safepoint();
4364 }
4365 #endif // INCLUDE_ALL_GCS
4366
4367 ALL_JAVA_THREADS(p) {
4368 ResourceMark rm;
4369 p->print_on(st);
4370 if (print_stacks) {
4371 if (internal_format) {
4372 p->trace_stack();
4373 } else {
4374 p->print_stack_on(st);
4375 }
4376 }
4377 st->cr();
4378 #if INCLUDE_ALL_GCS
4379 if (print_concurrent_locks) {
4380 concurrent_locks.print_locks_on(p, st);
4381 }
4382 #endif // INCLUDE_ALL_GCS
4383 }
4384
4385 VMThread::vm_thread()->print_on(st);
4386 st->cr();
4387 Universe::heap()->print_gc_threads_on(st);
4388 WatcherThread* wt = WatcherThread::watcher_thread();
4389 if (wt != NULL) {
4390 wt->print_on(st);
4391 st->cr();
4392 }
4393 CompileBroker::print_compiler_threads_on(st);
4394 st->flush();
4395 }
4396
4397 // Threads::print_on_error() is called by fatal error handler. It's possible
4398 // that VM is not at safepoint and/or current thread is inside signal handler.
4399 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4400 // memory (even in resource area), it might deadlock the error handler.
4401 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4402 bool found_current = false;
4403 st->print_cr("Java Threads: ( => current thread )");
4404 ALL_JAVA_THREADS(thread) {
4405 bool is_current = (current == thread);
4406 found_current = found_current || is_current;
4407
4408 st->print("%s", is_current ? "=>" : " ");
4409
4410 st->print(PTR_FORMAT, thread);
4411 st->print(" ");
4412 thread->print_on_error(st, buf, buflen);
4413 st->cr();
4414 }
4415 st->cr();
4416
4417 st->print_cr("Other Threads:");
4418 if (VMThread::vm_thread()) {
4419 bool is_current = (current == VMThread::vm_thread());
4420 found_current = found_current || is_current;
4421 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4422
4423 st->print(PTR_FORMAT, VMThread::vm_thread());
4424 st->print(" ");
4425 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4426 st->cr();
4427 }
4428 WatcherThread* wt = WatcherThread::watcher_thread();
4429 if (wt != NULL) {
4430 bool is_current = (current == wt);
4431 found_current = found_current || is_current;
4432 st->print("%s", is_current ? "=>" : " ");
4433
4434 st->print(PTR_FORMAT, wt);
4435 st->print(" ");
4436 wt->print_on_error(st, buf, buflen);
4437 st->cr();
4438 }
4439 if (!found_current) {
4440 st->cr();
4441 st->print("=>" PTR_FORMAT " (exited) ", current);
4442 current->print_on_error(st, buf, buflen);
4443 st->cr();
4444 }
4445 }
4446
4447 // Internal SpinLock and Mutex
4448 // Based on ParkEvent
4449
4450 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4451 //
4452 // We employ SpinLocks _only for low-contention, fixed-length
4453 // short-duration critical sections where we're concerned
4454 // about native mutex_t or HotSpot Mutex:: latency.
4455 // The mux construct provides a spin-then-block mutual exclusion
4456 // mechanism.
4457 //
4458 // Testing has shown that contention on the ListLock guarding gFreeList
4459 // is common. If we implement ListLock as a simple SpinLock it's common
4460 // for the JVM to devolve to yielding with little progress. This is true
4461 // despite the fact that the critical sections protected by ListLock are
4462 // extremely short.
4463 //
4464 // TODO-FIXME: ListLock should be of type SpinLock.
4465 // We should make this a 1st-class type, integrated into the lock
4466 // hierarchy as leaf-locks. Critically, the SpinLock structure
4467 // should have sufficient padding to avoid false-sharing and excessive
4468 // cache-coherency traffic.
4469
4470
4471 typedef volatile int SpinLockT ;
4472
4473 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4474 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4475 return ; // normal fast-path return
4476 }
4477
4478 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4479 TEVENT (SpinAcquire - ctx) ;
4480 int ctr = 0 ;
4481 int Yields = 0 ;
4482 for (;;) {
4483 while (*adr != 0) {
4484 ++ctr ;
4485 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4486 if (Yields > 5) {
4487 os::naked_short_sleep(1);
4488 } else {
4489 os::NakedYield() ;
4490 ++Yields ;
4491 }
4492 } else {
4493 SpinPause() ;
4494 }
4495 }
4496 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4497 }
4498 }
4499
4500 void Thread::SpinRelease (volatile int * adr) {
4501 assert (*adr != 0, "invariant") ;
4502 OrderAccess::fence() ; // guarantee at least release consistency.
4503 // Roach-motel semantics.
4504 // It's safe if subsequent LDs and STs float "up" into the critical section,
4505 // but prior LDs and STs within the critical section can't be allowed
4506 // to reorder or float past the ST that releases the lock.
4507 *adr = 0 ;
4508 }
4509
4510 // muxAcquire and muxRelease:
4511 //
4512 // * muxAcquire and muxRelease support a single-word lock-word construct.
4513 // The LSB of the word is set IFF the lock is held.
4514 // The remainder of the word points to the head of a singly-linked list
4515 // of threads blocked on the lock.
4516 //
4517 // * The current implementation of muxAcquire-muxRelease uses its own
4518 // dedicated Thread._MuxEvent instance. If we're interested in
4519 // minimizing the peak number of extant ParkEvent instances then
4520 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4521 // as certain invariants were satisfied. Specifically, care would need
4522 // to be taken with regards to consuming unpark() "permits".
4523 // A safe rule of thumb is that a thread would never call muxAcquire()
4524 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4525 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4526 // consume an unpark() permit intended for monitorenter, for instance.
4527 // One way around this would be to widen the restricted-range semaphore
4528 // implemented in park(). Another alternative would be to provide
4529 // multiple instances of the PlatformEvent() for each thread. One
4530 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4531 //
4532 // * Usage:
4533 // -- Only as leaf locks
4534 // -- for short-term locking only as muxAcquire does not perform
4535 // thread state transitions.
4536 //
4537 // Alternatives:
4538 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4539 // but with parking or spin-then-park instead of pure spinning.
4540 // * Use Taura-Oyama-Yonenzawa locks.
4541 // * It's possible to construct a 1-0 lock if we encode the lockword as
4542 // (List,LockByte). Acquire will CAS the full lockword while Release
4543 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4544 // acquiring threads use timers (ParkTimed) to detect and recover from
4545 // the stranding window. Thread/Node structures must be aligned on 256-byte
4546 // boundaries by using placement-new.
4547 // * Augment MCS with advisory back-link fields maintained with CAS().
4548 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4549 // The validity of the backlinks must be ratified before we trust the value.
4550 // If the backlinks are invalid the exiting thread must back-track through the
4551 // the forward links, which are always trustworthy.
4552 // * Add a successor indication. The LockWord is currently encoded as
4553 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4554 // to provide the usual futile-wakeup optimization.
4555 // See RTStt for details.
4556 // * Consider schedctl.sc_nopreempt to cover the critical section.
4557 //
4558
4559
4560 typedef volatile intptr_t MutexT ; // Mux Lock-word
4561 enum MuxBits { LOCKBIT = 1 } ;
4562
4563 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4564 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4565 if (w == 0) return ;
4566 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4567 return ;
4568 }
4569
4570 TEVENT (muxAcquire - Contention) ;
4571 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4572 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4573 for (;;) {
4574 int its = (os::is_MP() ? 100 : 0) + 1 ;
4575
4576 // Optional spin phase: spin-then-park strategy
4577 while (--its >= 0) {
4578 w = *Lock ;
4579 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4580 return ;
4581 }
4582 }
4583
4584 Self->reset() ;
4585 Self->OnList = intptr_t(Lock) ;
4586 // The following fence() isn't _strictly necessary as the subsequent
4587 // CAS() both serializes execution and ratifies the fetched *Lock value.
4588 OrderAccess::fence();
4589 for (;;) {
4590 w = *Lock ;
4591 if ((w & LOCKBIT) == 0) {
4592 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4593 Self->OnList = 0 ; // hygiene - allows stronger asserts
4594 return ;
4595 }
4596 continue ; // Interference -- *Lock changed -- Just retry
4597 }
4598 assert (w & LOCKBIT, "invariant") ;
4599 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4600 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4601 }
4602
4603 while (Self->OnList != 0) {
4604 Self->park() ;
4605 }
4606 }
4607 }
4608
4609 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4610 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4611 if (w == 0) return ;
4612 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4613 return ;
4614 }
4615
4616 TEVENT (muxAcquire - Contention) ;
4617 ParkEvent * ReleaseAfter = NULL ;
4618 if (ev == NULL) {
4619 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4620 }
4621 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4622 for (;;) {
4623 guarantee (ev->OnList == 0, "invariant") ;
4624 int its = (os::is_MP() ? 100 : 0) + 1 ;
4625
4626 // Optional spin phase: spin-then-park strategy
4627 while (--its >= 0) {
4628 w = *Lock ;
4629 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4630 if (ReleaseAfter != NULL) {
4631 ParkEvent::Release (ReleaseAfter) ;
4632 }
4633 return ;
4634 }
4635 }
4636
4637 ev->reset() ;
4638 ev->OnList = intptr_t(Lock) ;
4639 // The following fence() isn't _strictly necessary as the subsequent
4640 // CAS() both serializes execution and ratifies the fetched *Lock value.
4641 OrderAccess::fence();
4642 for (;;) {
4643 w = *Lock ;
4644 if ((w & LOCKBIT) == 0) {
4645 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4646 ev->OnList = 0 ;
4647 // We call ::Release while holding the outer lock, thus
4648 // artificially lengthening the critical section.
4649 // Consider deferring the ::Release() until the subsequent unlock(),
4650 // after we've dropped the outer lock.
4651 if (ReleaseAfter != NULL) {
4652 ParkEvent::Release (ReleaseAfter) ;
4653 }
4654 return ;
4655 }
4656 continue ; // Interference -- *Lock changed -- Just retry
4657 }
4658 assert (w & LOCKBIT, "invariant") ;
4659 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4660 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4661 }
4662
4663 while (ev->OnList != 0) {
4664 ev->park() ;
4665 }
4666 }
4667 }
4668
4669 // Release() must extract a successor from the list and then wake that thread.
4670 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4671 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4672 // Release() would :
4673 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4674 // (B) Extract a successor from the private list "in-hand"
4675 // (C) attempt to CAS() the residual back into *Lock over null.
4676 // If there were any newly arrived threads and the CAS() would fail.
4677 // In that case Release() would detach the RATs, re-merge the list in-hand
4678 // with the RATs and repeat as needed. Alternately, Release() might
4679 // detach and extract a successor, but then pass the residual list to the wakee.
4680 // The wakee would be responsible for reattaching and remerging before it
4681 // competed for the lock.
4682 //
4683 // Both "pop" and DMR are immune from ABA corruption -- there can be
4684 // multiple concurrent pushers, but only one popper or detacher.
4685 // This implementation pops from the head of the list. This is unfair,
4686 // but tends to provide excellent throughput as hot threads remain hot.
4687 // (We wake recently run threads first).
4688
4689 void Thread::muxRelease (volatile intptr_t * Lock) {
4690 for (;;) {
4691 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4692 assert (w & LOCKBIT, "invariant") ;
4693 if (w == LOCKBIT) return ;
4694 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4695 assert (List != NULL, "invariant") ;
4696 assert (List->OnList == intptr_t(Lock), "invariant") ;
4697 ParkEvent * nxt = List->ListNext ;
4698
4699 // The following CAS() releases the lock and pops the head element.
4700 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4701 continue ;
4702 }
4703 List->OnList = 0 ;
4704 OrderAccess::fence() ;
4705 List->unpark () ;
4706 return ;
4707 }
4708 }
4709
4710
4711 void Threads::verify() {
4712 ALL_JAVA_THREADS(p) {
4713 p->verify();
4714 }
4715 VMThread* thread = VMThread::vm_thread();
4716 if (thread != NULL) thread->verify();
4717 }