1 /*
2 * Copyright (c) 1997, 2013, 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/osThread.hpp"
62 #include "runtime/safepoint.hpp"
63 #include "runtime/sharedRuntime.hpp"
64 #include "runtime/statSampler.hpp"
65 #include "runtime/stubRoutines.hpp"
66 #include "runtime/task.hpp"
67 #include "runtime/thread.inline.hpp"
68 #include "runtime/threadCritical.hpp"
69 #include "runtime/threadLocalStorage.hpp"
70 #include "runtime/vframe.hpp"
71 #include "runtime/vframeArray.hpp"
72 #include "runtime/vframe_hp.hpp"
73 #include "runtime/vmThread.hpp"
74 #include "runtime/vm_operations.hpp"
75 #include "services/attachListener.hpp"
76 #include "services/management.hpp"
77 #include "services/memTracker.hpp"
78 #include "services/threadService.hpp"
79 #include "trace/tracing.hpp"
80 #include "trace/traceMacros.hpp"
81 #include "utilities/defaultStream.hpp"
82 #include "utilities/dtrace.hpp"
83 #include "utilities/events.hpp"
84 #include "utilities/preserveException.hpp"
85 #include "utilities/macros.hpp"
86 #ifdef TARGET_OS_FAMILY_linux
87 # include "os_linux.inline.hpp"
88 #endif
89 #ifdef TARGET_OS_FAMILY_solaris
90 # include "os_solaris.inline.hpp"
91 #endif
92 #ifdef TARGET_OS_FAMILY_windows
93 # include "os_windows.inline.hpp"
94 #endif
95 #ifdef TARGET_OS_FAMILY_bsd
96 # include "os_bsd.inline.hpp"
97 #endif
98 #if INCLUDE_ALL_GCS
99 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
100 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
101 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
102 #endif // INCLUDE_ALL_GCS
103 #ifdef COMPILER1
104 #include "c1/c1_Compiler.hpp"
105 #endif
106 #ifdef COMPILER2
107 #include "opto/c2compiler.hpp"
108 #include "opto/idealGraphPrinter.hpp"
109 #endif
110
111 #ifdef DTRACE_ENABLED
112
113 // Only bother with this argument setup if dtrace is available
114
115 #ifndef USDT2
116 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
117 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
118 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
119 intptr_t, intptr_t, bool);
120 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
121 intptr_t, intptr_t, bool);
122
123 #define DTRACE_THREAD_PROBE(probe, javathread) \
124 { \
125 ResourceMark rm(this); \
126 int len = 0; \
127 const char* name = (javathread)->get_thread_name(); \
128 len = strlen(name); \
129 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
130 name, len, \
131 java_lang_Thread::thread_id((javathread)->threadObj()), \
132 (javathread)->osthread()->thread_id(), \
133 java_lang_Thread::is_daemon((javathread)->threadObj())); \
134 }
135
136 #else /* USDT2 */
137
138 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
139 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
140
141 #define DTRACE_THREAD_PROBE(probe, javathread) \
142 { \
143 ResourceMark rm(this); \
144 int len = 0; \
145 const char* name = (javathread)->get_thread_name(); \
146 len = strlen(name); \
147 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
148 (char *) name, len, \
149 java_lang_Thread::thread_id((javathread)->threadObj()), \
150 (uintptr_t) (javathread)->osthread()->thread_id(), \
151 java_lang_Thread::is_daemon((javathread)->threadObj())); \
152 }
153
154 #endif /* USDT2 */
155
156 #else // ndef DTRACE_ENABLED
157
158 #define DTRACE_THREAD_PROBE(probe, javathread)
159
160 #endif // ndef DTRACE_ENABLED
161
162
163 // Class hierarchy
164 // - Thread
165 // - VMThread
166 // - WatcherThread
167 // - ConcurrentMarkSweepThread
168 // - JavaThread
169 // - CompilerThread
170
171 // ======= Thread ========
172 // Support for forcing alignment of thread objects for biased locking
173 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
174 if (UseBiasedLocking) {
175 const int alignment = markOopDesc::biased_lock_alignment;
176 size_t aligned_size = size + (alignment - sizeof(intptr_t));
177 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
178 : AllocateHeap(aligned_size, flags, CURRENT_PC,
179 AllocFailStrategy::RETURN_NULL);
180 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
181 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
182 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
183 "JavaThread alignment code overflowed allocated storage");
184 if (TraceBiasedLocking) {
185 if (aligned_addr != real_malloc_addr)
186 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
187 real_malloc_addr, aligned_addr);
188 }
189 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
190 return aligned_addr;
191 } else {
192 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
193 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
194 }
195 }
196
197 void Thread::operator delete(void* p) {
198 if (UseBiasedLocking) {
199 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
200 FreeHeap(real_malloc_addr, mtThread);
201 } else {
202 FreeHeap(p, mtThread);
203 }
204 }
205
206
207 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
208 // JavaThread
209
210
211 Thread::Thread() {
212 // stack and get_thread
213 set_stack_base(NULL);
214 set_stack_size(0);
215 set_self_raw_id(0);
216 set_lgrp_id(-1);
217
218 // allocated data structures
219 set_osthread(NULL);
220 set_resource_area(new (mtThread)ResourceArea());
221 DEBUG_ONLY(_current_resource_mark = NULL;)
222 set_handle_area(new (mtThread) HandleArea(NULL));
223 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
224 set_active_handles(NULL);
225 set_free_handle_block(NULL);
226 set_last_handle_mark(NULL);
227
228 // This initial value ==> never claimed.
229 _oops_do_parity = 0;
230
231 // the handle mark links itself to last_handle_mark
232 new HandleMark(this);
233
234 // plain initialization
235 debug_only(_owned_locks = NULL;)
236 debug_only(_allow_allocation_count = 0;)
237 NOT_PRODUCT(_allow_safepoint_count = 0;)
238 NOT_PRODUCT(_skip_gcalot = false;)
239 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
240 _jvmti_env_iteration_count = 0;
241 set_allocated_bytes(0);
242 _vm_operation_started_count = 0;
243 _vm_operation_completed_count = 0;
244 _current_pending_monitor = NULL;
245 _current_pending_monitor_is_from_java = true;
246 _current_waiting_monitor = NULL;
247 _num_nested_signal = 0;
248 omFreeList = NULL ;
249 omFreeCount = 0 ;
250 omFreeProvision = 32 ;
251 omInUseList = NULL ;
252 omInUseCount = 0 ;
253
254 #ifdef ASSERT
255 _visited_for_critical_count = false;
256 #endif
257
258 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
259 _suspend_flags = 0;
260
261 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
262 _hashStateX = os::random() ;
263 _hashStateY = 842502087 ;
264 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
265 _hashStateW = 273326509 ;
266
267 _OnTrap = 0 ;
268 _schedctl = NULL ;
269 _Stalled = 0 ;
270 _TypeTag = 0x2BAD ;
271
272 // Many of the following fields are effectively final - immutable
273 // Note that nascent threads can't use the Native Monitor-Mutex
274 // construct until the _MutexEvent is initialized ...
275 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
276 // we might instead use a stack of ParkEvents that we could provision on-demand.
277 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
278 // and ::Release()
279 _ParkEvent = ParkEvent::Allocate (this) ;
280 _SleepEvent = ParkEvent::Allocate (this) ;
281 _MutexEvent = ParkEvent::Allocate (this) ;
282 _MuxEvent = ParkEvent::Allocate (this) ;
283
284 #ifdef CHECK_UNHANDLED_OOPS
285 if (CheckUnhandledOops) {
286 _unhandled_oops = new UnhandledOops(this);
287 }
288 #endif // CHECK_UNHANDLED_OOPS
289 #ifdef ASSERT
290 if (UseBiasedLocking) {
291 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
292 assert(this == _real_malloc_address ||
293 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
294 "bug in forced alignment of thread objects");
295 }
296 #endif /* ASSERT */
297 }
298
299 void Thread::initialize_thread_local_storage() {
300 // Note: Make sure this method only calls
301 // non-blocking operations. Otherwise, it might not work
302 // with the thread-startup/safepoint interaction.
303
304 // During Java thread startup, safepoint code should allow this
305 // method to complete because it may need to allocate memory to
306 // store information for the new thread.
307
308 // initialize structure dependent on thread local storage
309 ThreadLocalStorage::set_thread(this);
310 }
311
312 void Thread::record_stack_base_and_size() {
313 set_stack_base(os::current_stack_base());
314 set_stack_size(os::current_stack_size());
315 // CR 7190089: on Solaris, primordial thread's stack is adjusted
316 // in initialize_thread(). Without the adjustment, stack size is
317 // incorrect if stack is set to unlimited (ulimit -s unlimited).
318 // So far, only Solaris has real implementation of initialize_thread().
319 //
320 // set up any platform-specific state.
321 os::initialize_thread(this);
322
323 #if INCLUDE_NMT
324 // record thread's native stack, stack grows downward
325 address stack_low_addr = stack_base() - stack_size();
326 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this,
327 CURRENT_PC);
328 #endif // INCLUDE_NMT
329 }
330
331
332 Thread::~Thread() {
333 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
334 ObjectSynchronizer::omFlush (this) ;
335
336 EVENT_THREAD_DESTRUCT(this);
337
338 // stack_base can be NULL if the thread is never started or exited before
339 // record_stack_base_and_size called. Although, we would like to ensure
340 // that all started threads do call record_stack_base_and_size(), there is
341 // not proper way to enforce that.
342 #if INCLUDE_NMT
343 if (_stack_base != NULL) {
344 address low_stack_addr = stack_base() - stack_size();
345 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this);
346 #ifdef ASSERT
347 set_stack_base(NULL);
348 #endif
349 }
350 #endif // INCLUDE_NMT
351
352 // deallocate data structures
353 delete resource_area();
354 // since the handle marks are using the handle area, we have to deallocated the root
355 // handle mark before deallocating the thread's handle area,
356 assert(last_handle_mark() != NULL, "check we have an element");
357 delete last_handle_mark();
358 assert(last_handle_mark() == NULL, "check we have reached the end");
359
360 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
361 // We NULL out the fields for good hygiene.
362 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
363 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
364 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
365 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
366
367 delete handle_area();
368 delete metadata_handles();
369
370 // osthread() can be NULL, if creation of thread failed.
371 if (osthread() != NULL) os::free_thread(osthread());
372
373 delete _SR_lock;
374
375 // clear thread local storage if the Thread is deleting itself
376 if (this == Thread::current()) {
377 ThreadLocalStorage::set_thread(NULL);
378 } else {
379 // In the case where we're not the current thread, invalidate all the
380 // caches in case some code tries to get the current thread or the
381 // thread that was destroyed, and gets stale information.
382 ThreadLocalStorage::invalidate_all();
383 }
384 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
385 }
386
387 // NOTE: dummy function for assertion purpose.
388 void Thread::run() {
389 ShouldNotReachHere();
390 }
391
392 #ifdef ASSERT
393 // Private method to check for dangling thread pointer
394 void check_for_dangling_thread_pointer(Thread *thread) {
395 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
396 "possibility of dangling Thread pointer");
397 }
398 #endif
399
400
401 #ifndef PRODUCT
402 // Tracing method for basic thread operations
403 void Thread::trace(const char* msg, const Thread* const thread) {
404 if (!TraceThreadEvents) return;
405 ResourceMark rm;
406 ThreadCritical tc;
407 const char *name = "non-Java thread";
408 int prio = -1;
409 if (thread->is_Java_thread()
410 && !thread->is_Compiler_thread()) {
411 // The Threads_lock must be held to get information about
412 // this thread but may not be in some situations when
413 // tracing thread events.
414 bool release_Threads_lock = false;
415 if (!Threads_lock->owned_by_self()) {
416 Threads_lock->lock();
417 release_Threads_lock = true;
418 }
419 JavaThread* jt = (JavaThread *)thread;
420 name = (char *)jt->get_thread_name();
421 oop thread_oop = jt->threadObj();
422 if (thread_oop != NULL) {
423 prio = java_lang_Thread::priority(thread_oop);
424 }
425 if (release_Threads_lock) {
426 Threads_lock->unlock();
427 }
428 }
429 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
430 }
431 #endif
432
433
434 ThreadPriority Thread::get_priority(const Thread* const thread) {
435 trace("get priority", thread);
436 ThreadPriority priority;
437 // Can return an error!
438 (void)os::get_priority(thread, priority);
439 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
440 return priority;
441 }
442
443 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
444 trace("set priority", thread);
445 debug_only(check_for_dangling_thread_pointer(thread);)
446 // Can return an error!
447 (void)os::set_priority(thread, priority);
448 }
449
450
451 void Thread::start(Thread* thread) {
452 trace("start", thread);
453 // Start is different from resume in that its safety is guaranteed by context or
454 // being called from a Java method synchronized on the Thread object.
455 if (!DisableStartThread) {
456 if (thread->is_Java_thread()) {
457 // Initialize the thread state to RUNNABLE before starting this thread.
458 // Can not set it after the thread started because we do not know the
459 // exact thread state at that time. It could be in MONITOR_WAIT or
460 // in SLEEPING or some other state.
461 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
462 java_lang_Thread::RUNNABLE);
463 }
464 os::start_thread(thread);
465 }
466 }
467
468 // Enqueue a VM_Operation to do the job for us - sometime later
469 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
470 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
471 VMThread::execute(vm_stop);
472 }
473
474
475 //
476 // Check if an external suspend request has completed (or has been
477 // cancelled). Returns true if the thread is externally suspended and
478 // false otherwise.
479 //
480 // The bits parameter returns information about the code path through
481 // the routine. Useful for debugging:
482 //
483 // set in is_ext_suspend_completed():
484 // 0x00000001 - routine was entered
485 // 0x00000010 - routine return false at end
486 // 0x00000100 - thread exited (return false)
487 // 0x00000200 - suspend request cancelled (return false)
488 // 0x00000400 - thread suspended (return true)
489 // 0x00001000 - thread is in a suspend equivalent state (return true)
490 // 0x00002000 - thread is native and walkable (return true)
491 // 0x00004000 - thread is native_trans and walkable (needed retry)
492 //
493 // set in wait_for_ext_suspend_completion():
494 // 0x00010000 - routine was entered
495 // 0x00020000 - suspend request cancelled before loop (return false)
496 // 0x00040000 - thread suspended before loop (return true)
497 // 0x00080000 - suspend request cancelled in loop (return false)
498 // 0x00100000 - thread suspended in loop (return true)
499 // 0x00200000 - suspend not completed during retry loop (return false)
500 //
501
502 // Helper class for tracing suspend wait debug bits.
503 //
504 // 0x00000100 indicates that the target thread exited before it could
505 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
506 // 0x00080000 each indicate a cancelled suspend request so they don't
507 // count as wait failures either.
508 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
509
510 class TraceSuspendDebugBits : public StackObj {
511 private:
512 JavaThread * jt;
513 bool is_wait;
514 bool called_by_wait; // meaningful when !is_wait
515 uint32_t * bits;
516
517 public:
518 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
519 uint32_t *_bits) {
520 jt = _jt;
521 is_wait = _is_wait;
522 called_by_wait = _called_by_wait;
523 bits = _bits;
524 }
525
526 ~TraceSuspendDebugBits() {
527 if (!is_wait) {
528 #if 1
529 // By default, don't trace bits for is_ext_suspend_completed() calls.
530 // That trace is very chatty.
531 return;
532 #else
533 if (!called_by_wait) {
534 // If tracing for is_ext_suspend_completed() is enabled, then only
535 // trace calls to it from wait_for_ext_suspend_completion()
536 return;
537 }
538 #endif
539 }
540
541 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
542 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
543 MutexLocker ml(Threads_lock); // needed for get_thread_name()
544 ResourceMark rm;
545
546 tty->print_cr(
547 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
548 jt->get_thread_name(), *bits);
549
550 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
551 }
552 }
553 }
554 };
555 #undef DEBUG_FALSE_BITS
556
557
558 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
559 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
560
561 bool did_trans_retry = false; // only do thread_in_native_trans retry once
562 bool do_trans_retry; // flag to force the retry
563
564 *bits |= 0x00000001;
565
566 do {
567 do_trans_retry = false;
568
569 if (is_exiting()) {
570 // Thread is in the process of exiting. This is always checked
571 // first to reduce the risk of dereferencing a freed JavaThread.
572 *bits |= 0x00000100;
573 return false;
574 }
575
576 if (!is_external_suspend()) {
577 // Suspend request is cancelled. This is always checked before
578 // is_ext_suspended() to reduce the risk of a rogue resume
579 // confusing the thread that made the suspend request.
580 *bits |= 0x00000200;
581 return false;
582 }
583
584 if (is_ext_suspended()) {
585 // thread is suspended
586 *bits |= 0x00000400;
587 return true;
588 }
589
590 // Now that we no longer do hard suspends of threads running
591 // native code, the target thread can be changing thread state
592 // while we are in this routine:
593 //
594 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
595 //
596 // We save a copy of the thread state as observed at this moment
597 // and make our decision about suspend completeness based on the
598 // copy. This closes the race where the thread state is seen as
599 // _thread_in_native_trans in the if-thread_blocked check, but is
600 // seen as _thread_blocked in if-thread_in_native_trans check.
601 JavaThreadState save_state = thread_state();
602
603 if (save_state == _thread_blocked && is_suspend_equivalent()) {
604 // If the thread's state is _thread_blocked and this blocking
605 // condition is known to be equivalent to a suspend, then we can
606 // consider the thread to be externally suspended. This means that
607 // the code that sets _thread_blocked has been modified to do
608 // self-suspension if the blocking condition releases. We also
609 // used to check for CONDVAR_WAIT here, but that is now covered by
610 // the _thread_blocked with self-suspension check.
611 //
612 // Return true since we wouldn't be here unless there was still an
613 // external suspend request.
614 *bits |= 0x00001000;
615 return true;
616 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
617 // Threads running native code will self-suspend on native==>VM/Java
618 // transitions. If its stack is walkable (should always be the case
619 // unless this function is called before the actual java_suspend()
620 // call), then the wait is done.
621 *bits |= 0x00002000;
622 return true;
623 } else if (!called_by_wait && !did_trans_retry &&
624 save_state == _thread_in_native_trans &&
625 frame_anchor()->walkable()) {
626 // The thread is transitioning from thread_in_native to another
627 // thread state. check_safepoint_and_suspend_for_native_trans()
628 // will force the thread to self-suspend. If it hasn't gotten
629 // there yet we may have caught the thread in-between the native
630 // code check above and the self-suspend. Lucky us. If we were
631 // called by wait_for_ext_suspend_completion(), then it
632 // will be doing the retries so we don't have to.
633 //
634 // Since we use the saved thread state in the if-statement above,
635 // there is a chance that the thread has already transitioned to
636 // _thread_blocked by the time we get here. In that case, we will
637 // make a single unnecessary pass through the logic below. This
638 // doesn't hurt anything since we still do the trans retry.
639
640 *bits |= 0x00004000;
641
642 // Once the thread leaves thread_in_native_trans for another
643 // thread state, we break out of this retry loop. We shouldn't
644 // need this flag to prevent us from getting back here, but
645 // sometimes paranoia is good.
646 did_trans_retry = true;
647
648 // We wait for the thread to transition to a more usable state.
649 for (int i = 1; i <= SuspendRetryCount; i++) {
650 // We used to do an "os::yield_all(i)" call here with the intention
651 // that yielding would increase on each retry. However, the parameter
652 // is ignored on Linux which means the yield didn't scale up. Waiting
653 // on the SR_lock below provides a much more predictable scale up for
654 // the delay. It also provides a simple/direct point to check for any
655 // safepoint requests from the VMThread
656
657 // temporarily drops SR_lock while doing wait with safepoint check
658 // (if we're a JavaThread - the WatcherThread can also call this)
659 // and increase delay with each retry
660 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
661
662 // check the actual thread state instead of what we saved above
663 if (thread_state() != _thread_in_native_trans) {
664 // the thread has transitioned to another thread state so
665 // try all the checks (except this one) one more time.
666 do_trans_retry = true;
667 break;
668 }
669 } // end retry loop
670
671
672 }
673 } while (do_trans_retry);
674
675 *bits |= 0x00000010;
676 return false;
677 }
678
679 //
680 // Wait for an external suspend request to complete (or be cancelled).
681 // Returns true if the thread is externally suspended and false otherwise.
682 //
683 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
684 uint32_t *bits) {
685 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
686 false /* !called_by_wait */, bits);
687
688 // local flag copies to minimize SR_lock hold time
689 bool is_suspended;
690 bool pending;
691 uint32_t reset_bits;
692
693 // set a marker so is_ext_suspend_completed() knows we are the caller
694 *bits |= 0x00010000;
695
696 // We use reset_bits to reinitialize the bits value at the top of
697 // each retry loop. This allows the caller to make use of any
698 // unused bits for their own marking purposes.
699 reset_bits = *bits;
700
701 {
702 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
703 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
704 delay, bits);
705 pending = is_external_suspend();
706 }
707 // must release SR_lock to allow suspension to complete
708
709 if (!pending) {
710 // A cancelled suspend request is the only false return from
711 // is_ext_suspend_completed() that keeps us from entering the
712 // retry loop.
713 *bits |= 0x00020000;
714 return false;
715 }
716
717 if (is_suspended) {
718 *bits |= 0x00040000;
719 return true;
720 }
721
722 for (int i = 1; i <= retries; i++) {
723 *bits = reset_bits; // reinit to only track last retry
724
725 // We used to do an "os::yield_all(i)" call here with the intention
726 // that yielding would increase on each retry. However, the parameter
727 // is ignored on Linux which means the yield didn't scale up. Waiting
728 // on the SR_lock below provides a much more predictable scale up for
729 // the delay. It also provides a simple/direct point to check for any
730 // safepoint requests from the VMThread
731
732 {
733 MutexLocker ml(SR_lock());
734 // wait with safepoint check (if we're a JavaThread - the WatcherThread
735 // can also call this) and increase delay with each retry
736 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
737
738 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
739 delay, bits);
740
741 // It is possible for the external suspend request to be cancelled
742 // (by a resume) before the actual suspend operation is completed.
743 // Refresh our local copy to see if we still need to wait.
744 pending = is_external_suspend();
745 }
746
747 if (!pending) {
748 // A cancelled suspend request is the only false return from
749 // is_ext_suspend_completed() that keeps us from staying in the
750 // retry loop.
751 *bits |= 0x00080000;
752 return false;
753 }
754
755 if (is_suspended) {
756 *bits |= 0x00100000;
757 return true;
758 }
759 } // end retry loop
760
761 // thread did not suspend after all our retries
762 *bits |= 0x00200000;
763 return false;
764 }
765
766 #ifndef PRODUCT
767 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
768
769 // This should not need to be atomic as the only way for simultaneous
770 // updates is via interrupts. Even then this should be rare or non-existant
771 // and we don't care that much anyway.
772
773 int index = _jmp_ring_index;
774 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
775 _jmp_ring[index]._target = (intptr_t) target;
776 _jmp_ring[index]._instruction = (intptr_t) instr;
777 _jmp_ring[index]._file = file;
778 _jmp_ring[index]._line = line;
779 }
780 #endif /* PRODUCT */
781
782 // Called by flat profiler
783 // Callers have already called wait_for_ext_suspend_completion
784 // The assertion for that is currently too complex to put here:
785 bool JavaThread::profile_last_Java_frame(frame* _fr) {
786 bool gotframe = false;
787 // self suspension saves needed state.
788 if (has_last_Java_frame() && _anchor.walkable()) {
789 *_fr = pd_last_frame();
790 gotframe = true;
791 }
792 return gotframe;
793 }
794
795 void Thread::interrupt(Thread* thread) {
796 trace("interrupt", thread);
797 debug_only(check_for_dangling_thread_pointer(thread);)
798 os::interrupt(thread);
799 }
800
801 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
802 trace("is_interrupted", thread);
803 debug_only(check_for_dangling_thread_pointer(thread);)
804 // Note: If clear_interrupted==false, this simply fetches and
805 // returns the value of the field osthread()->interrupted().
806 return os::is_interrupted(thread, clear_interrupted);
807 }
808
809
810 // GC Support
811 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
812 jint thread_parity = _oops_do_parity;
813 if (thread_parity != strong_roots_parity) {
814 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
815 if (res == thread_parity) {
816 return true;
817 } else {
818 guarantee(res == strong_roots_parity, "Or else what?");
819 assert(SharedHeap::heap()->workers()->active_workers() > 0,
820 "Should only fail when parallel.");
821 return false;
822 }
823 }
824 assert(SharedHeap::heap()->workers()->active_workers() > 0,
825 "Should only fail when parallel.");
826 return false;
827 }
828
829 void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
830 active_handles()->oops_do(f);
831 // Do oop for ThreadShadow
832 f->do_oop((oop*)&_pending_exception);
833 handle_area()->oops_do(f);
834 }
835
836 void Thread::nmethods_do(CodeBlobClosure* cf) {
837 // no nmethods in a generic thread...
838 }
839
840 void Thread::metadata_do(void f(Metadata*)) {
841 if (metadata_handles() != NULL) {
842 for (int i = 0; i< metadata_handles()->length(); i++) {
843 f(metadata_handles()->at(i));
844 }
845 }
846 }
847
848 void Thread::print_on(outputStream* st) const {
849 // get_priority assumes osthread initialized
850 if (osthread() != NULL) {
851 int os_prio;
852 if (os::get_native_priority(this, &os_prio) == OS_OK) {
853 st->print("os_prio=%d ", os_prio);
854 }
855 st->print("tid=" INTPTR_FORMAT " ", this);
856 osthread()->print_on(st);
857 }
858 debug_only(if (WizardMode) print_owned_locks_on(st);)
859 }
860
861 // Thread::print_on_error() is called by fatal error handler. Don't use
862 // any lock or allocate memory.
863 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
864 if (is_VM_thread()) st->print("VMThread");
865 else if (is_Compiler_thread()) st->print("CompilerThread");
866 else if (is_Java_thread()) st->print("JavaThread");
867 else if (is_GC_task_thread()) st->print("GCTaskThread");
868 else if (is_Watcher_thread()) st->print("WatcherThread");
869 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
870 else st->print("Thread");
871
872 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
873 _stack_base - _stack_size, _stack_base);
874
875 if (osthread()) {
876 st->print(" [id=%d]", osthread()->thread_id());
877 }
878 }
879
880 #ifdef ASSERT
881 void Thread::print_owned_locks_on(outputStream* st) const {
882 Monitor *cur = _owned_locks;
883 if (cur == NULL) {
884 st->print(" (no locks) ");
885 } else {
886 st->print_cr(" Locks owned:");
887 while(cur) {
888 cur->print_on(st);
889 cur = cur->next();
890 }
891 }
892 }
893
894 static int ref_use_count = 0;
895
896 bool Thread::owns_locks_but_compiled_lock() const {
897 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
898 if (cur != Compile_lock) return true;
899 }
900 return false;
901 }
902
903
904 #endif
905
906 #ifndef PRODUCT
907
908 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
909 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
910 // no threads which allow_vm_block's are held
911 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
912 // Check if current thread is allowed to block at a safepoint
913 if (!(_allow_safepoint_count == 0))
914 fatal("Possible safepoint reached by thread that does not allow it");
915 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
916 fatal("LEAF method calling lock?");
917 }
918
919 #ifdef ASSERT
920 if (potential_vm_operation && is_Java_thread()
921 && !Universe::is_bootstrapping()) {
922 // Make sure we do not hold any locks that the VM thread also uses.
923 // This could potentially lead to deadlocks
924 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
925 // Threads_lock is special, since the safepoint synchronization will not start before this is
926 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
927 // since it is used to transfer control between JavaThreads and the VMThread
928 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
929 if ( (cur->allow_vm_block() &&
930 cur != Threads_lock &&
931 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
932 cur != VMOperationRequest_lock &&
933 cur != VMOperationQueue_lock) ||
934 cur->rank() == Mutex::special) {
935 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
936 }
937 }
938 }
939
940 if (GCALotAtAllSafepoints) {
941 // We could enter a safepoint here and thus have a gc
942 InterfaceSupport::check_gc_alot();
943 }
944 #endif
945 }
946 #endif
947
948 bool Thread::is_in_stack(address adr) const {
949 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
950 address end = os::current_stack_pointer();
951 // Allow non Java threads to call this without stack_base
952 if (_stack_base == NULL) return true;
953 if (stack_base() >= adr && adr >= end) return true;
954
955 return false;
956 }
957
958
959 bool Thread::is_in_usable_stack(address adr) const {
960 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
961 size_t usable_stack_size = _stack_size - stack_guard_size;
962
963 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
964 }
965
966
967 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
968 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
969 // used for compilation in the future. If that change is made, the need for these methods
970 // should be revisited, and they should be removed if possible.
971
972 bool Thread::is_lock_owned(address adr) const {
973 return on_local_stack(adr);
974 }
975
976 bool Thread::set_as_starting_thread() {
977 // NOTE: this must be called inside the main thread.
978 return os::create_main_thread((JavaThread*)this);
979 }
980
981 static void initialize_class(Symbol* class_name, TRAPS) {
982 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
983 InstanceKlass::cast(klass)->initialize(CHECK);
984 }
985
986
987 // Creates the initial ThreadGroup
988 static Handle create_initial_thread_group(TRAPS) {
989 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
990 instanceKlassHandle klass (THREAD, k);
991
992 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
993 {
994 JavaValue result(T_VOID);
995 JavaCalls::call_special(&result,
996 system_instance,
997 klass,
998 vmSymbols::object_initializer_name(),
999 vmSymbols::void_method_signature(),
1000 CHECK_NH);
1001 }
1002 Universe::set_system_thread_group(system_instance());
1003
1004 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1005 {
1006 JavaValue result(T_VOID);
1007 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1008 JavaCalls::call_special(&result,
1009 main_instance,
1010 klass,
1011 vmSymbols::object_initializer_name(),
1012 vmSymbols::threadgroup_string_void_signature(),
1013 system_instance,
1014 string,
1015 CHECK_NH);
1016 }
1017 return main_instance;
1018 }
1019
1020 // Creates the initial Thread
1021 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1022 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1023 instanceKlassHandle klass (THREAD, k);
1024 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1025
1026 java_lang_Thread::set_thread(thread_oop(), thread);
1027 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1028 thread->set_threadObj(thread_oop());
1029
1030 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1031
1032 JavaValue result(T_VOID);
1033 JavaCalls::call_special(&result, thread_oop,
1034 klass,
1035 vmSymbols::object_initializer_name(),
1036 vmSymbols::threadgroup_string_void_signature(),
1037 thread_group,
1038 string,
1039 CHECK_NULL);
1040 return thread_oop();
1041 }
1042
1043 static void call_initializeSystemClass(TRAPS) {
1044 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1045 instanceKlassHandle klass (THREAD, k);
1046
1047 JavaValue result(T_VOID);
1048 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1049 vmSymbols::void_method_signature(), CHECK);
1050 }
1051
1052 char java_runtime_name[128] = "";
1053 char java_runtime_version[128] = "";
1054
1055 // extract the JRE name from sun.misc.Version.java_runtime_name
1056 static const char* get_java_runtime_name(TRAPS) {
1057 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1058 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1059 fieldDescriptor fd;
1060 bool found = k != NULL &&
1061 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1062 vmSymbols::string_signature(), &fd);
1063 if (found) {
1064 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1065 if (name_oop == NULL)
1066 return NULL;
1067 const char* name = java_lang_String::as_utf8_string(name_oop,
1068 java_runtime_name,
1069 sizeof(java_runtime_name));
1070 return name;
1071 } else {
1072 return NULL;
1073 }
1074 }
1075
1076 // extract the JRE version from sun.misc.Version.java_runtime_version
1077 static const char* get_java_runtime_version(TRAPS) {
1078 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1079 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1080 fieldDescriptor fd;
1081 bool found = k != NULL &&
1082 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1083 vmSymbols::string_signature(), &fd);
1084 if (found) {
1085 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1086 if (name_oop == NULL)
1087 return NULL;
1088 const char* name = java_lang_String::as_utf8_string(name_oop,
1089 java_runtime_version,
1090 sizeof(java_runtime_version));
1091 return name;
1092 } else {
1093 return NULL;
1094 }
1095 }
1096
1097 // General purpose hook into Java code, run once when the VM is initialized.
1098 // The Java library method itself may be changed independently from the VM.
1099 static void call_postVMInitHook(TRAPS) {
1100 Klass* k = SystemDictionary::PostVMInitHook_klass();
1101 instanceKlassHandle klass (THREAD, k);
1102 if (klass.not_null()) {
1103 JavaValue result(T_VOID);
1104 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1105 vmSymbols::void_method_signature(),
1106 CHECK);
1107 }
1108 }
1109
1110 static void reset_vm_info_property(TRAPS) {
1111 // the vm info string
1112 ResourceMark rm(THREAD);
1113 const char *vm_info = VM_Version::vm_info_string();
1114
1115 // java.lang.System class
1116 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1117 instanceKlassHandle klass (THREAD, k);
1118
1119 // setProperty arguments
1120 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1121 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1122
1123 // return value
1124 JavaValue r(T_OBJECT);
1125
1126 // public static String setProperty(String key, String value);
1127 JavaCalls::call_static(&r,
1128 klass,
1129 vmSymbols::setProperty_name(),
1130 vmSymbols::string_string_string_signature(),
1131 key_str,
1132 value_str,
1133 CHECK);
1134 }
1135
1136
1137 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1138 assert(thread_group.not_null(), "thread group should be specified");
1139 assert(threadObj() == NULL, "should only create Java thread object once");
1140
1141 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1142 instanceKlassHandle klass (THREAD, k);
1143 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1144
1145 java_lang_Thread::set_thread(thread_oop(), this);
1146 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1147 set_threadObj(thread_oop());
1148
1149 JavaValue result(T_VOID);
1150 if (thread_name != NULL) {
1151 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1152 // Thread gets assigned specified name and null target
1153 JavaCalls::call_special(&result,
1154 thread_oop,
1155 klass,
1156 vmSymbols::object_initializer_name(),
1157 vmSymbols::threadgroup_string_void_signature(),
1158 thread_group, // Argument 1
1159 name, // Argument 2
1160 THREAD);
1161 } else {
1162 // Thread gets assigned name "Thread-nnn" and null target
1163 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1164 JavaCalls::call_special(&result,
1165 thread_oop,
1166 klass,
1167 vmSymbols::object_initializer_name(),
1168 vmSymbols::threadgroup_runnable_void_signature(),
1169 thread_group, // Argument 1
1170 Handle(), // Argument 2
1171 THREAD);
1172 }
1173
1174
1175 if (daemon) {
1176 java_lang_Thread::set_daemon(thread_oop());
1177 }
1178
1179 if (HAS_PENDING_EXCEPTION) {
1180 return;
1181 }
1182
1183 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1184 Handle threadObj(this, this->threadObj());
1185
1186 JavaCalls::call_special(&result,
1187 thread_group,
1188 group,
1189 vmSymbols::add_method_name(),
1190 vmSymbols::thread_void_signature(),
1191 threadObj, // Arg 1
1192 THREAD);
1193
1194
1195 }
1196
1197 // NamedThread -- non-JavaThread subclasses with multiple
1198 // uniquely named instances should derive from this.
1199 NamedThread::NamedThread() : Thread() {
1200 _name = NULL;
1201 _processed_thread = NULL;
1202 }
1203
1204 NamedThread::~NamedThread() {
1205 if (_name != NULL) {
1206 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1207 _name = NULL;
1208 }
1209 }
1210
1211 void NamedThread::set_name(const char* format, ...) {
1212 guarantee(_name == NULL, "Only get to set name once.");
1213 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1214 guarantee(_name != NULL, "alloc failure");
1215 va_list ap;
1216 va_start(ap, format);
1217 jio_vsnprintf(_name, max_name_len, format, ap);
1218 va_end(ap);
1219 }
1220
1221 // ======= WatcherThread ========
1222
1223 // The watcher thread exists to simulate timer interrupts. It should
1224 // be replaced by an abstraction over whatever native support for
1225 // timer interrupts exists on the platform.
1226
1227 WatcherThread* WatcherThread::_watcher_thread = NULL;
1228 bool WatcherThread::_startable = false;
1229 volatile bool WatcherThread::_should_terminate = false;
1230
1231 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1232 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1233 if (os::create_thread(this, os::watcher_thread)) {
1234 _watcher_thread = this;
1235
1236 // Set the watcher thread to the highest OS priority which should not be
1237 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1238 // is created. The only normal thread using this priority is the reference
1239 // handler thread, which runs for very short intervals only.
1240 // If the VMThread's priority is not lower than the WatcherThread profiling
1241 // will be inaccurate.
1242 os::set_priority(this, MaxPriority);
1243 if (!DisableStartThread) {
1244 os::start_thread(this);
1245 }
1246 }
1247 }
1248
1249 int WatcherThread::sleep() const {
1250 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1251
1252 // remaining will be zero if there are no tasks,
1253 // causing the WatcherThread to sleep until a task is
1254 // enrolled
1255 int remaining = PeriodicTask::time_to_wait();
1256 int time_slept = 0;
1257
1258 // we expect this to timeout - we only ever get unparked when
1259 // we should terminate or when a new task has been enrolled
1260 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1261
1262 jlong time_before_loop = os::javaTimeNanos();
1263
1264 for (;;) {
1265 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1266 jlong now = os::javaTimeNanos();
1267
1268 if (remaining == 0) {
1269 // if we didn't have any tasks we could have waited for a long time
1270 // consider the time_slept zero and reset time_before_loop
1271 time_slept = 0;
1272 time_before_loop = now;
1273 } else {
1274 // need to recalulate since we might have new tasks in _tasks
1275 time_slept = (int) ((now - time_before_loop) / 1000000);
1276 }
1277
1278 // Change to task list or spurious wakeup of some kind
1279 if (timedout || _should_terminate) {
1280 break;
1281 }
1282
1283 remaining = PeriodicTask::time_to_wait();
1284 if (remaining == 0) {
1285 // Last task was just disenrolled so loop around and wait until
1286 // another task gets enrolled
1287 continue;
1288 }
1289
1290 remaining -= time_slept;
1291 if (remaining <= 0)
1292 break;
1293 }
1294
1295 return time_slept;
1296 }
1297
1298 void WatcherThread::run() {
1299 assert(this == watcher_thread(), "just checking");
1300
1301 this->record_stack_base_and_size();
1302 this->initialize_thread_local_storage();
1303 this->set_active_handles(JNIHandleBlock::allocate_block());
1304 while(!_should_terminate) {
1305 assert(watcher_thread() == Thread::current(), "thread consistency check");
1306 assert(watcher_thread() == this, "thread consistency check");
1307
1308 // Calculate how long it'll be until the next PeriodicTask work
1309 // should be done, and sleep that amount of time.
1310 int time_waited = sleep();
1311
1312 if (is_error_reported()) {
1313 // A fatal error has happened, the error handler(VMError::report_and_die)
1314 // should abort JVM after creating an error log file. However in some
1315 // rare cases, the error handler itself might deadlock. Here we try to
1316 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1317 //
1318 // This code is in WatcherThread because WatcherThread wakes up
1319 // periodically so the fatal error handler doesn't need to do anything;
1320 // also because the WatcherThread is less likely to crash than other
1321 // threads.
1322
1323 for (;;) {
1324 if (!ShowMessageBoxOnError
1325 && (OnError == NULL || OnError[0] == '\0')
1326 && Arguments::abort_hook() == NULL) {
1327 os::sleep(this, 2 * 60 * 1000, false);
1328 fdStream err(defaultStream::output_fd());
1329 err.print_raw_cr("# [ timer expired, abort... ]");
1330 // skip atexit/vm_exit/vm_abort hooks
1331 os::die();
1332 }
1333
1334 // Wake up 5 seconds later, the fatal handler may reset OnError or
1335 // ShowMessageBoxOnError when it is ready to abort.
1336 os::sleep(this, 5 * 1000, false);
1337 }
1338 }
1339
1340 PeriodicTask::real_time_tick(time_waited);
1341 }
1342
1343 // Signal that it is terminated
1344 {
1345 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1346 _watcher_thread = NULL;
1347 Terminator_lock->notify();
1348 }
1349
1350 // Thread destructor usually does this..
1351 ThreadLocalStorage::set_thread(NULL);
1352 }
1353
1354 void WatcherThread::start() {
1355 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1356
1357 if (watcher_thread() == NULL && _startable) {
1358 _should_terminate = false;
1359 // Create the single instance of WatcherThread
1360 new WatcherThread();
1361 }
1362 }
1363
1364 void WatcherThread::make_startable() {
1365 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1366 _startable = true;
1367 }
1368
1369 void WatcherThread::stop() {
1370 {
1371 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1372 _should_terminate = true;
1373 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1374
1375 WatcherThread* watcher = watcher_thread();
1376 if (watcher != NULL)
1377 watcher->unpark();
1378 }
1379
1380 // it is ok to take late safepoints here, if needed
1381 MutexLocker mu(Terminator_lock);
1382
1383 while(watcher_thread() != NULL) {
1384 // This wait should make safepoint checks, wait without a timeout,
1385 // and wait as a suspend-equivalent condition.
1386 //
1387 // Note: If the FlatProfiler is running, then this thread is waiting
1388 // for the WatcherThread to terminate and the WatcherThread, via the
1389 // FlatProfiler task, is waiting for the external suspend request on
1390 // this thread to complete. wait_for_ext_suspend_completion() will
1391 // eventually timeout, but that takes time. Making this wait a
1392 // suspend-equivalent condition solves that timeout problem.
1393 //
1394 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1395 Mutex::_as_suspend_equivalent_flag);
1396 }
1397 }
1398
1399 void WatcherThread::unpark() {
1400 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1401 PeriodicTask_lock->notify();
1402 }
1403
1404 void WatcherThread::print_on(outputStream* st) const {
1405 st->print("\"%s\" ", name());
1406 Thread::print_on(st);
1407 st->cr();
1408 }
1409
1410 // ======= JavaThread ========
1411
1412 // A JavaThread is a normal Java thread
1413
1414 void JavaThread::initialize() {
1415 // Initialize fields
1416
1417 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1418 set_claimed_par_id(-1);
1419
1420 set_saved_exception_pc(NULL);
1421 set_threadObj(NULL);
1422 _anchor.clear();
1423 set_entry_point(NULL);
1424 set_jni_functions(jni_functions());
1425 set_callee_target(NULL);
1426 set_vm_result(NULL);
1427 set_vm_result_2(NULL);
1428 set_vframe_array_head(NULL);
1429 set_vframe_array_last(NULL);
1430 set_deferred_locals(NULL);
1431 set_deopt_mark(NULL);
1432 set_deopt_nmethod(NULL);
1433 clear_must_deopt_id();
1434 set_monitor_chunks(NULL);
1435 set_next(NULL);
1436 set_thread_state(_thread_new);
1437 #if INCLUDE_NMT
1438 set_recorder(NULL);
1439 #endif
1440 _terminated = _not_terminated;
1441 _privileged_stack_top = NULL;
1442 _array_for_gc = NULL;
1443 _suspend_equivalent = false;
1444 _in_deopt_handler = 0;
1445 _doing_unsafe_access = false;
1446 _stack_guard_state = stack_guard_unused;
1447 _exception_oop = NULL;
1448 _exception_pc = 0;
1449 _exception_handler_pc = 0;
1450 _is_method_handle_return = 0;
1451 _jvmti_thread_state= NULL;
1452 _should_post_on_exceptions_flag = JNI_FALSE;
1453 _jvmti_get_loaded_classes_closure = NULL;
1454 _interp_only_mode = 0;
1455 _special_runtime_exit_condition = _no_async_condition;
1456 _pending_async_exception = NULL;
1457 _is_compiling = false;
1458 _thread_stat = NULL;
1459 _thread_stat = new ThreadStatistics();
1460 _blocked_on_compilation = false;
1461 _jni_active_critical = 0;
1462 _do_not_unlock_if_synchronized = false;
1463 _cached_monitor_info = NULL;
1464 _parker = Parker::Allocate(this) ;
1465
1466 #ifndef PRODUCT
1467 _jmp_ring_index = 0;
1468 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1469 record_jump(NULL, NULL, NULL, 0);
1470 }
1471 #endif /* PRODUCT */
1472
1473 set_thread_profiler(NULL);
1474 if (FlatProfiler::is_active()) {
1475 // This is where we would decide to either give each thread it's own profiler
1476 // or use one global one from FlatProfiler,
1477 // or up to some count of the number of profiled threads, etc.
1478 ThreadProfiler* pp = new ThreadProfiler();
1479 pp->engage();
1480 set_thread_profiler(pp);
1481 }
1482
1483 // Setup safepoint state info for this thread
1484 ThreadSafepointState::create(this);
1485
1486 debug_only(_java_call_counter = 0);
1487
1488 // JVMTI PopFrame support
1489 _popframe_condition = popframe_inactive;
1490 _popframe_preserved_args = NULL;
1491 _popframe_preserved_args_size = 0;
1492
1493 pd_initialize();
1494 }
1495
1496 #if INCLUDE_ALL_GCS
1497 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1498 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1499 #endif // INCLUDE_ALL_GCS
1500
1501 JavaThread::JavaThread(bool is_attaching_via_jni) :
1502 Thread()
1503 #if INCLUDE_ALL_GCS
1504 , _satb_mark_queue(&_satb_mark_queue_set),
1505 _dirty_card_queue(&_dirty_card_queue_set)
1506 #endif // INCLUDE_ALL_GCS
1507 {
1508 initialize();
1509 if (is_attaching_via_jni) {
1510 _jni_attach_state = _attaching_via_jni;
1511 } else {
1512 _jni_attach_state = _not_attaching_via_jni;
1513 }
1514 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1515 _safepoint_visible = false;
1516 }
1517
1518 bool JavaThread::reguard_stack(address cur_sp) {
1519 if (_stack_guard_state != stack_guard_yellow_disabled) {
1520 return true; // Stack already guarded or guard pages not needed.
1521 }
1522
1523 if (register_stack_overflow()) {
1524 // For those architectures which have separate register and
1525 // memory stacks, we must check the register stack to see if
1526 // it has overflowed.
1527 return false;
1528 }
1529
1530 // Java code never executes within the yellow zone: the latter is only
1531 // there to provoke an exception during stack banging. If java code
1532 // is executing there, either StackShadowPages should be larger, or
1533 // some exception code in c1, c2 or the interpreter isn't unwinding
1534 // when it should.
1535 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1536
1537 enable_stack_yellow_zone();
1538 return true;
1539 }
1540
1541 bool JavaThread::reguard_stack(void) {
1542 return reguard_stack(os::current_stack_pointer());
1543 }
1544
1545
1546 void JavaThread::block_if_vm_exited() {
1547 if (_terminated == _vm_exited) {
1548 // _vm_exited is set at safepoint, and Threads_lock is never released
1549 // we will block here forever
1550 Threads_lock->lock_without_safepoint_check();
1551 ShouldNotReachHere();
1552 }
1553 }
1554
1555
1556 // Remove this ifdef when C1 is ported to the compiler interface.
1557 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1558
1559 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1560 Thread()
1561 #if INCLUDE_ALL_GCS
1562 , _satb_mark_queue(&_satb_mark_queue_set),
1563 _dirty_card_queue(&_dirty_card_queue_set)
1564 #endif // INCLUDE_ALL_GCS
1565 {
1566 if (TraceThreadEvents) {
1567 tty->print_cr("creating thread %p", this);
1568 }
1569 initialize();
1570 _jni_attach_state = _not_attaching_via_jni;
1571 set_entry_point(entry_point);
1572 // Create the native thread itself.
1573 // %note runtime_23
1574 os::ThreadType thr_type = os::java_thread;
1575 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1576 os::java_thread;
1577 os::create_thread(this, thr_type, stack_sz);
1578 _safepoint_visible = false;
1579 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1580 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1581 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1582 // the exception consists of creating the exception object & initializing it, initialization
1583 // will leave the VM via a JavaCall and then all locks must be unlocked).
1584 //
1585 // The thread is still suspended when we reach here. Thread must be explicit started
1586 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1587 // by calling Threads:add. The reason why this is not done here, is because the thread
1588 // object must be fully initialized (take a look at JVM_Start)
1589 }
1590
1591 JavaThread::~JavaThread() {
1592 if (TraceThreadEvents) {
1593 tty->print_cr("terminate thread %p", this);
1594 }
1595
1596 // By now, this thread should already be invisible to safepoint,
1597 // and its per-thread recorder also collected.
1598 assert(!is_safepoint_visible(), "wrong state");
1599 #if INCLUDE_NMT
1600 assert(get_recorder() == NULL, "Already collected");
1601 #endif // INCLUDE_NMT
1602
1603 // JSR166 -- return the parker to the free list
1604 Parker::Release(_parker);
1605 _parker = NULL ;
1606
1607 // Free any remaining previous UnrollBlock
1608 vframeArray* old_array = vframe_array_last();
1609
1610 if (old_array != NULL) {
1611 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1612 old_array->set_unroll_block(NULL);
1613 delete old_info;
1614 delete old_array;
1615 }
1616
1617 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1618 if (deferred != NULL) {
1619 // This can only happen if thread is destroyed before deoptimization occurs.
1620 assert(deferred->length() != 0, "empty array!");
1621 do {
1622 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1623 deferred->remove_at(0);
1624 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1625 delete dlv;
1626 } while (deferred->length() != 0);
1627 delete deferred;
1628 }
1629
1630 // All Java related clean up happens in exit
1631 ThreadSafepointState::destroy(this);
1632 if (_thread_profiler != NULL) delete _thread_profiler;
1633 if (_thread_stat != NULL) delete _thread_stat;
1634 }
1635
1636
1637 // The first routine called by a new Java thread
1638 void JavaThread::run() {
1639 // initialize thread-local alloc buffer related fields
1640 this->initialize_tlab();
1641
1642 // used to test validitity of stack trace backs
1643 this->record_base_of_stack_pointer();
1644
1645 // Record real stack base and size.
1646 this->record_stack_base_and_size();
1647
1648 // Initialize thread local storage; set before calling MutexLocker
1649 this->initialize_thread_local_storage();
1650
1651 this->create_stack_guard_pages();
1652
1653 this->cache_global_variables();
1654
1655 // Thread is now sufficient initialized to be handled by the safepoint code as being
1656 // in the VM. Change thread state from _thread_new to _thread_in_vm
1657 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1658
1659 assert(JavaThread::current() == this, "sanity check");
1660 assert(!Thread::current()->owns_locks(), "sanity check");
1661
1662 DTRACE_THREAD_PROBE(start, this);
1663
1664 // This operation might block. We call that after all safepoint checks for a new thread has
1665 // been completed.
1666 this->set_active_handles(JNIHandleBlock::allocate_block());
1667
1668 if (JvmtiExport::should_post_thread_life()) {
1669 JvmtiExport::post_thread_start(this);
1670 }
1671
1672 EventThreadStart event;
1673 if (event.should_commit()) {
1674 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1675 event.commit();
1676 }
1677
1678 // We call another function to do the rest so we are sure that the stack addresses used
1679 // from there will be lower than the stack base just computed
1680 thread_main_inner();
1681
1682 // Note, thread is no longer valid at this point!
1683 }
1684
1685
1686 void JavaThread::thread_main_inner() {
1687 assert(JavaThread::current() == this, "sanity check");
1688 assert(this->threadObj() != NULL, "just checking");
1689
1690 // Execute thread entry point unless this thread has a pending exception
1691 // or has been stopped before starting.
1692 // Note: Due to JVM_StopThread we can have pending exceptions already!
1693 if (!this->has_pending_exception() &&
1694 !java_lang_Thread::is_stillborn(this->threadObj())) {
1695 {
1696 ResourceMark rm(this);
1697 this->set_native_thread_name(this->get_thread_name());
1698 }
1699 HandleMark hm(this);
1700 this->entry_point()(this, this);
1701 }
1702
1703 DTRACE_THREAD_PROBE(stop, this);
1704
1705 this->exit(false);
1706 delete this;
1707 }
1708
1709
1710 static void ensure_join(JavaThread* thread) {
1711 // We do not need to grap the Threads_lock, since we are operating on ourself.
1712 Handle threadObj(thread, thread->threadObj());
1713 assert(threadObj.not_null(), "java thread object must exist");
1714 ObjectLocker lock(threadObj, thread);
1715 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1716 thread->clear_pending_exception();
1717 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1718 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1719 // Clear the native thread instance - this makes isAlive return false and allows the join()
1720 // to complete once we've done the notify_all below
1721 java_lang_Thread::set_thread(threadObj(), NULL);
1722 lock.notify_all(thread);
1723 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1724 thread->clear_pending_exception();
1725 }
1726
1727
1728 // For any new cleanup additions, please check to see if they need to be applied to
1729 // cleanup_failed_attach_current_thread as well.
1730 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1731 assert(this == JavaThread::current(), "thread consistency check");
1732
1733 HandleMark hm(this);
1734 Handle uncaught_exception(this, this->pending_exception());
1735 this->clear_pending_exception();
1736 Handle threadObj(this, this->threadObj());
1737 assert(threadObj.not_null(), "Java thread object should be created");
1738
1739 if (get_thread_profiler() != NULL) {
1740 get_thread_profiler()->disengage();
1741 ResourceMark rm;
1742 get_thread_profiler()->print(get_thread_name());
1743 }
1744
1745
1746 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1747 {
1748 EXCEPTION_MARK;
1749
1750 CLEAR_PENDING_EXCEPTION;
1751 }
1752 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1753 // has to be fixed by a runtime query method
1754 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1755 // JSR-166: change call from from ThreadGroup.uncaughtException to
1756 // java.lang.Thread.dispatchUncaughtException
1757 if (uncaught_exception.not_null()) {
1758 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1759 {
1760 EXCEPTION_MARK;
1761 // Check if the method Thread.dispatchUncaughtException() exists. If so
1762 // call it. Otherwise we have an older library without the JSR-166 changes,
1763 // so call ThreadGroup.uncaughtException()
1764 KlassHandle recvrKlass(THREAD, threadObj->klass());
1765 CallInfo callinfo;
1766 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1767 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1768 vmSymbols::dispatchUncaughtException_name(),
1769 vmSymbols::throwable_void_signature(),
1770 KlassHandle(), false, false, THREAD);
1771 CLEAR_PENDING_EXCEPTION;
1772 methodHandle method = callinfo.selected_method();
1773 if (method.not_null()) {
1774 JavaValue result(T_VOID);
1775 JavaCalls::call_virtual(&result,
1776 threadObj, thread_klass,
1777 vmSymbols::dispatchUncaughtException_name(),
1778 vmSymbols::throwable_void_signature(),
1779 uncaught_exception,
1780 THREAD);
1781 } else {
1782 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1783 JavaValue result(T_VOID);
1784 JavaCalls::call_virtual(&result,
1785 group, thread_group,
1786 vmSymbols::uncaughtException_name(),
1787 vmSymbols::thread_throwable_void_signature(),
1788 threadObj, // Arg 1
1789 uncaught_exception, // Arg 2
1790 THREAD);
1791 }
1792 if (HAS_PENDING_EXCEPTION) {
1793 ResourceMark rm(this);
1794 jio_fprintf(defaultStream::error_stream(),
1795 "\nException: %s thrown from the UncaughtExceptionHandler"
1796 " in thread \"%s\"\n",
1797 pending_exception()->klass()->external_name(),
1798 get_thread_name());
1799 CLEAR_PENDING_EXCEPTION;
1800 }
1801 }
1802 }
1803
1804 // Called before the java thread exit since we want to read info
1805 // from java_lang_Thread object
1806 EventThreadEnd event;
1807 if (event.should_commit()) {
1808 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1809 event.commit();
1810 }
1811
1812 // Call after last event on thread
1813 EVENT_THREAD_EXIT(this);
1814
1815 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1816 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1817 // is deprecated anyhow.
1818 { int count = 3;
1819 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1820 EXCEPTION_MARK;
1821 JavaValue result(T_VOID);
1822 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1823 JavaCalls::call_virtual(&result,
1824 threadObj, thread_klass,
1825 vmSymbols::exit_method_name(),
1826 vmSymbols::void_method_signature(),
1827 THREAD);
1828 CLEAR_PENDING_EXCEPTION;
1829 }
1830 }
1831
1832 // notify JVMTI
1833 if (JvmtiExport::should_post_thread_life()) {
1834 JvmtiExport::post_thread_end(this);
1835 }
1836
1837 // We have notified the agents that we are exiting, before we go on,
1838 // we must check for a pending external suspend request and honor it
1839 // in order to not surprise the thread that made the suspend request.
1840 while (true) {
1841 {
1842 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1843 if (!is_external_suspend()) {
1844 set_terminated(_thread_exiting);
1845 ThreadService::current_thread_exiting(this);
1846 break;
1847 }
1848 // Implied else:
1849 // Things get a little tricky here. We have a pending external
1850 // suspend request, but we are holding the SR_lock so we
1851 // can't just self-suspend. So we temporarily drop the lock
1852 // and then self-suspend.
1853 }
1854
1855 ThreadBlockInVM tbivm(this);
1856 java_suspend_self();
1857
1858 // We're done with this suspend request, but we have to loop around
1859 // and check again. Eventually we will get SR_lock without a pending
1860 // external suspend request and will be able to mark ourselves as
1861 // exiting.
1862 }
1863 // no more external suspends are allowed at this point
1864 } else {
1865 // before_exit() has already posted JVMTI THREAD_END events
1866 }
1867
1868 // Notify waiters on thread object. This has to be done after exit() is called
1869 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1870 // group should have the destroyed bit set before waiters are notified).
1871 ensure_join(this);
1872 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1873
1874 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1875 // held by this thread must be released. A detach operation must only
1876 // get here if there are no Java frames on the stack. Therefore, any
1877 // owned monitors at this point MUST be JNI-acquired monitors which are
1878 // pre-inflated and in the monitor cache.
1879 //
1880 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1881 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1882 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1883 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1884 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1885 }
1886
1887 // These things needs to be done while we are still a Java Thread. Make sure that thread
1888 // is in a consistent state, in case GC happens
1889 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1890
1891 if (active_handles() != NULL) {
1892 JNIHandleBlock* block = active_handles();
1893 set_active_handles(NULL);
1894 JNIHandleBlock::release_block(block);
1895 }
1896
1897 if (free_handle_block() != NULL) {
1898 JNIHandleBlock* block = free_handle_block();
1899 set_free_handle_block(NULL);
1900 JNIHandleBlock::release_block(block);
1901 }
1902
1903 // These have to be removed while this is still a valid thread.
1904 remove_stack_guard_pages();
1905
1906 if (UseTLAB) {
1907 tlab().make_parsable(true); // retire TLAB
1908 }
1909
1910 if (JvmtiEnv::environments_might_exist()) {
1911 JvmtiExport::cleanup_thread(this);
1912 }
1913
1914 // We must flush any deferred card marks before removing a thread from
1915 // the list of active threads.
1916 Universe::heap()->flush_deferred_store_barrier(this);
1917 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1918
1919 #if INCLUDE_ALL_GCS
1920 // We must flush the G1-related buffers before removing a thread
1921 // from the list of active threads. We must do this after any deferred
1922 // card marks have been flushed (above) so that any entries that are
1923 // added to the thread's dirty card queue as a result are not lost.
1924 if (UseG1GC) {
1925 flush_barrier_queues();
1926 }
1927 #endif // INCLUDE_ALL_GCS
1928
1929 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1930 Threads::remove(this);
1931 }
1932
1933 #if INCLUDE_ALL_GCS
1934 // Flush G1-related queues.
1935 void JavaThread::flush_barrier_queues() {
1936 satb_mark_queue().flush();
1937 dirty_card_queue().flush();
1938 }
1939
1940 void JavaThread::initialize_queues() {
1941 assert(!SafepointSynchronize::is_at_safepoint(),
1942 "we should not be at a safepoint");
1943
1944 ObjPtrQueue& satb_queue = satb_mark_queue();
1945 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1946 // The SATB queue should have been constructed with its active
1947 // field set to false.
1948 assert(!satb_queue.is_active(), "SATB queue should not be active");
1949 assert(satb_queue.is_empty(), "SATB queue should be empty");
1950 // If we are creating the thread during a marking cycle, we should
1951 // set the active field of the SATB queue to true.
1952 if (satb_queue_set.is_active()) {
1953 satb_queue.set_active(true);
1954 }
1955
1956 DirtyCardQueue& dirty_queue = dirty_card_queue();
1957 // The dirty card queue should have been constructed with its
1958 // active field set to true.
1959 assert(dirty_queue.is_active(), "dirty card queue should be active");
1960 }
1961 #endif // INCLUDE_ALL_GCS
1962
1963 void JavaThread::cleanup_failed_attach_current_thread() {
1964 if (get_thread_profiler() != NULL) {
1965 get_thread_profiler()->disengage();
1966 ResourceMark rm;
1967 get_thread_profiler()->print(get_thread_name());
1968 }
1969
1970 if (active_handles() != NULL) {
1971 JNIHandleBlock* block = active_handles();
1972 set_active_handles(NULL);
1973 JNIHandleBlock::release_block(block);
1974 }
1975
1976 if (free_handle_block() != NULL) {
1977 JNIHandleBlock* block = free_handle_block();
1978 set_free_handle_block(NULL);
1979 JNIHandleBlock::release_block(block);
1980 }
1981
1982 // These have to be removed while this is still a valid thread.
1983 remove_stack_guard_pages();
1984
1985 if (UseTLAB) {
1986 tlab().make_parsable(true); // retire TLAB, if any
1987 }
1988
1989 #if INCLUDE_ALL_GCS
1990 if (UseG1GC) {
1991 flush_barrier_queues();
1992 }
1993 #endif // INCLUDE_ALL_GCS
1994
1995 Threads::remove(this);
1996 delete this;
1997 }
1998
1999
2000
2001
2002 JavaThread* JavaThread::active() {
2003 Thread* thread = ThreadLocalStorage::thread();
2004 assert(thread != NULL, "just checking");
2005 if (thread->is_Java_thread()) {
2006 return (JavaThread*) thread;
2007 } else {
2008 assert(thread->is_VM_thread(), "this must be a vm thread");
2009 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2010 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2011 assert(ret->is_Java_thread(), "must be a Java thread");
2012 return ret;
2013 }
2014 }
2015
2016 bool JavaThread::is_lock_owned(address adr) const {
2017 if (Thread::is_lock_owned(adr)) return true;
2018
2019 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2020 if (chunk->contains(adr)) return true;
2021 }
2022
2023 return false;
2024 }
2025
2026
2027 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2028 chunk->set_next(monitor_chunks());
2029 set_monitor_chunks(chunk);
2030 }
2031
2032 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2033 guarantee(monitor_chunks() != NULL, "must be non empty");
2034 if (monitor_chunks() == chunk) {
2035 set_monitor_chunks(chunk->next());
2036 } else {
2037 MonitorChunk* prev = monitor_chunks();
2038 while (prev->next() != chunk) prev = prev->next();
2039 prev->set_next(chunk->next());
2040 }
2041 }
2042
2043 // JVM support.
2044
2045 // Note: this function shouldn't block if it's called in
2046 // _thread_in_native_trans state (such as from
2047 // check_special_condition_for_native_trans()).
2048 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2049
2050 if (has_last_Java_frame() && has_async_condition()) {
2051 // If we are at a polling page safepoint (not a poll return)
2052 // then we must defer async exception because live registers
2053 // will be clobbered by the exception path. Poll return is
2054 // ok because the call we a returning from already collides
2055 // with exception handling registers and so there is no issue.
2056 // (The exception handling path kills call result registers but
2057 // this is ok since the exception kills the result anyway).
2058
2059 if (is_at_poll_safepoint()) {
2060 // if the code we are returning to has deoptimized we must defer
2061 // the exception otherwise live registers get clobbered on the
2062 // exception path before deoptimization is able to retrieve them.
2063 //
2064 RegisterMap map(this, false);
2065 frame caller_fr = last_frame().sender(&map);
2066 assert(caller_fr.is_compiled_frame(), "what?");
2067 if (caller_fr.is_deoptimized_frame()) {
2068 if (TraceExceptions) {
2069 ResourceMark rm;
2070 tty->print_cr("deferred async exception at compiled safepoint");
2071 }
2072 return;
2073 }
2074 }
2075 }
2076
2077 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2078 if (condition == _no_async_condition) {
2079 // Conditions have changed since has_special_runtime_exit_condition()
2080 // was called:
2081 // - if we were here only because of an external suspend request,
2082 // then that was taken care of above (or cancelled) so we are done
2083 // - if we were here because of another async request, then it has
2084 // been cleared between the has_special_runtime_exit_condition()
2085 // and now so again we are done
2086 return;
2087 }
2088
2089 // Check for pending async. exception
2090 if (_pending_async_exception != NULL) {
2091 // Only overwrite an already pending exception, if it is not a threadDeath.
2092 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2093
2094 // We cannot call Exceptions::_throw(...) here because we cannot block
2095 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2096
2097 if (TraceExceptions) {
2098 ResourceMark rm;
2099 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2100 if (has_last_Java_frame() ) {
2101 frame f = last_frame();
2102 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2103 }
2104 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2105 }
2106 _pending_async_exception = NULL;
2107 clear_has_async_exception();
2108 }
2109 }
2110
2111 if (check_unsafe_error &&
2112 condition == _async_unsafe_access_error && !has_pending_exception()) {
2113 condition = _no_async_condition; // done
2114 switch (thread_state()) {
2115 case _thread_in_vm:
2116 {
2117 JavaThread* THREAD = this;
2118 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2119 }
2120 case _thread_in_native:
2121 {
2122 ThreadInVMfromNative tiv(this);
2123 JavaThread* THREAD = this;
2124 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2125 }
2126 case _thread_in_Java:
2127 {
2128 ThreadInVMfromJava tiv(this);
2129 JavaThread* THREAD = this;
2130 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2131 }
2132 default:
2133 ShouldNotReachHere();
2134 }
2135 }
2136
2137 assert(condition == _no_async_condition || has_pending_exception() ||
2138 (!check_unsafe_error && condition == _async_unsafe_access_error),
2139 "must have handled the async condition, if no exception");
2140 }
2141
2142 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2143 //
2144 // Check for pending external suspend. Internal suspend requests do
2145 // not use handle_special_runtime_exit_condition().
2146 // If JNIEnv proxies are allowed, don't self-suspend if the target
2147 // thread is not the current thread. In older versions of jdbx, jdbx
2148 // threads could call into the VM with another thread's JNIEnv so we
2149 // can be here operating on behalf of a suspended thread (4432884).
2150 bool do_self_suspend = is_external_suspend_with_lock();
2151 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2152 //
2153 // Because thread is external suspended the safepoint code will count
2154 // thread as at a safepoint. This can be odd because we can be here
2155 // as _thread_in_Java which would normally transition to _thread_blocked
2156 // at a safepoint. We would like to mark the thread as _thread_blocked
2157 // before calling java_suspend_self like all other callers of it but
2158 // we must then observe proper safepoint protocol. (We can't leave
2159 // _thread_blocked with a safepoint in progress). However we can be
2160 // here as _thread_in_native_trans so we can't use a normal transition
2161 // constructor/destructor pair because they assert on that type of
2162 // transition. We could do something like:
2163 //
2164 // JavaThreadState state = thread_state();
2165 // set_thread_state(_thread_in_vm);
2166 // {
2167 // ThreadBlockInVM tbivm(this);
2168 // java_suspend_self()
2169 // }
2170 // set_thread_state(_thread_in_vm_trans);
2171 // if (safepoint) block;
2172 // set_thread_state(state);
2173 //
2174 // but that is pretty messy. Instead we just go with the way the
2175 // code has worked before and note that this is the only path to
2176 // java_suspend_self that doesn't put the thread in _thread_blocked
2177 // mode.
2178
2179 frame_anchor()->make_walkable(this);
2180 java_suspend_self();
2181
2182 // We might be here for reasons in addition to the self-suspend request
2183 // so check for other async requests.
2184 }
2185
2186 if (check_asyncs) {
2187 check_and_handle_async_exceptions();
2188 }
2189 }
2190
2191 void JavaThread::send_thread_stop(oop java_throwable) {
2192 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2193 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2194 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2195
2196 // Do not throw asynchronous exceptions against the compiler thread
2197 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2198 if (is_Compiler_thread()) return;
2199
2200 {
2201 // Actually throw the Throwable against the target Thread - however
2202 // only if there is no thread death exception installed already.
2203 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2204 // If the topmost frame is a runtime stub, then we are calling into
2205 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2206 // must deoptimize the caller before continuing, as the compiled exception handler table
2207 // may not be valid
2208 if (has_last_Java_frame()) {
2209 frame f = last_frame();
2210 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2211 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2212 RegisterMap reg_map(this, UseBiasedLocking);
2213 frame compiled_frame = f.sender(®_map);
2214 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2215 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2216 }
2217 }
2218 }
2219
2220 // Set async. pending exception in thread.
2221 set_pending_async_exception(java_throwable);
2222
2223 if (TraceExceptions) {
2224 ResourceMark rm;
2225 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2226 }
2227 // for AbortVMOnException flag
2228 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2229 }
2230 }
2231
2232
2233 // Interrupt thread so it will wake up from a potential wait()
2234 Thread::interrupt(this);
2235 }
2236
2237 // External suspension mechanism.
2238 //
2239 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2240 // to any VM_locks and it is at a transition
2241 // Self-suspension will happen on the transition out of the vm.
2242 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2243 //
2244 // Guarantees on return:
2245 // + Target thread will not execute any new bytecode (that's why we need to
2246 // force a safepoint)
2247 // + Target thread will not enter any new monitors
2248 //
2249 void JavaThread::java_suspend() {
2250 { MutexLocker mu(Threads_lock);
2251 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2252 return;
2253 }
2254 }
2255
2256 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2257 if (!is_external_suspend()) {
2258 // a racing resume has cancelled us; bail out now
2259 return;
2260 }
2261
2262 // suspend is done
2263 uint32_t debug_bits = 0;
2264 // Warning: is_ext_suspend_completed() may temporarily drop the
2265 // SR_lock to allow the thread to reach a stable thread state if
2266 // it is currently in a transient thread state.
2267 if (is_ext_suspend_completed(false /* !called_by_wait */,
2268 SuspendRetryDelay, &debug_bits) ) {
2269 return;
2270 }
2271 }
2272
2273 VM_ForceSafepoint vm_suspend;
2274 VMThread::execute(&vm_suspend);
2275 }
2276
2277 // Part II of external suspension.
2278 // A JavaThread self suspends when it detects a pending external suspend
2279 // request. This is usually on transitions. It is also done in places
2280 // where continuing to the next transition would surprise the caller,
2281 // e.g., monitor entry.
2282 //
2283 // Returns the number of times that the thread self-suspended.
2284 //
2285 // Note: DO NOT call java_suspend_self() when you just want to block current
2286 // thread. java_suspend_self() is the second stage of cooperative
2287 // suspension for external suspend requests and should only be used
2288 // to complete an external suspend request.
2289 //
2290 int JavaThread::java_suspend_self() {
2291 int ret = 0;
2292
2293 // we are in the process of exiting so don't suspend
2294 if (is_exiting()) {
2295 clear_external_suspend();
2296 return ret;
2297 }
2298
2299 assert(_anchor.walkable() ||
2300 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2301 "must have walkable stack");
2302
2303 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2304
2305 assert(!this->is_ext_suspended(),
2306 "a thread trying to self-suspend should not already be suspended");
2307
2308 if (this->is_suspend_equivalent()) {
2309 // If we are self-suspending as a result of the lifting of a
2310 // suspend equivalent condition, then the suspend_equivalent
2311 // flag is not cleared until we set the ext_suspended flag so
2312 // that wait_for_ext_suspend_completion() returns consistent
2313 // results.
2314 this->clear_suspend_equivalent();
2315 }
2316
2317 // A racing resume may have cancelled us before we grabbed SR_lock
2318 // above. Or another external suspend request could be waiting for us
2319 // by the time we return from SR_lock()->wait(). The thread
2320 // that requested the suspension may already be trying to walk our
2321 // stack and if we return now, we can change the stack out from under
2322 // it. This would be a "bad thing (TM)" and cause the stack walker
2323 // to crash. We stay self-suspended until there are no more pending
2324 // external suspend requests.
2325 while (is_external_suspend()) {
2326 ret++;
2327 this->set_ext_suspended();
2328
2329 // _ext_suspended flag is cleared by java_resume()
2330 while (is_ext_suspended()) {
2331 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2332 }
2333 }
2334
2335 return ret;
2336 }
2337
2338 #ifdef ASSERT
2339 // verify the JavaThread has not yet been published in the Threads::list, and
2340 // hence doesn't need protection from concurrent access at this stage
2341 void JavaThread::verify_not_published() {
2342 if (!Threads_lock->owned_by_self()) {
2343 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2344 assert( !Threads::includes(this),
2345 "java thread shouldn't have been published yet!");
2346 }
2347 else {
2348 assert( !Threads::includes(this),
2349 "java thread shouldn't have been published yet!");
2350 }
2351 }
2352 #endif
2353
2354 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2355 // progress or when _suspend_flags is non-zero.
2356 // Current thread needs to self-suspend if there is a suspend request and/or
2357 // block if a safepoint is in progress.
2358 // Async exception ISN'T checked.
2359 // Note only the ThreadInVMfromNative transition can call this function
2360 // directly and when thread state is _thread_in_native_trans
2361 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2362 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2363
2364 JavaThread *curJT = JavaThread::current();
2365 bool do_self_suspend = thread->is_external_suspend();
2366
2367 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2368
2369 // If JNIEnv proxies are allowed, don't self-suspend if the target
2370 // thread is not the current thread. In older versions of jdbx, jdbx
2371 // threads could call into the VM with another thread's JNIEnv so we
2372 // can be here operating on behalf of a suspended thread (4432884).
2373 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2374 JavaThreadState state = thread->thread_state();
2375
2376 // We mark this thread_blocked state as a suspend-equivalent so
2377 // that a caller to is_ext_suspend_completed() won't be confused.
2378 // The suspend-equivalent state is cleared by java_suspend_self().
2379 thread->set_suspend_equivalent();
2380
2381 // If the safepoint code sees the _thread_in_native_trans state, it will
2382 // wait until the thread changes to other thread state. There is no
2383 // guarantee on how soon we can obtain the SR_lock and complete the
2384 // self-suspend request. It would be a bad idea to let safepoint wait for
2385 // too long. Temporarily change the state to _thread_blocked to
2386 // let the VM thread know that this thread is ready for GC. The problem
2387 // of changing thread state is that safepoint could happen just after
2388 // java_suspend_self() returns after being resumed, and VM thread will
2389 // see the _thread_blocked state. We must check for safepoint
2390 // after restoring the state and make sure we won't leave while a safepoint
2391 // is in progress.
2392 thread->set_thread_state(_thread_blocked);
2393 thread->java_suspend_self();
2394 thread->set_thread_state(state);
2395 // Make sure new state is seen by VM thread
2396 if (os::is_MP()) {
2397 if (UseMembar) {
2398 // Force a fence between the write above and read below
2399 OrderAccess::fence();
2400 } else {
2401 // Must use this rather than serialization page in particular on Windows
2402 InterfaceSupport::serialize_memory(thread);
2403 }
2404 }
2405 }
2406
2407 if (SafepointSynchronize::do_call_back()) {
2408 // If we are safepointing, then block the caller which may not be
2409 // the same as the target thread (see above).
2410 SafepointSynchronize::block(curJT);
2411 }
2412
2413 if (thread->is_deopt_suspend()) {
2414 thread->clear_deopt_suspend();
2415 RegisterMap map(thread, false);
2416 frame f = thread->last_frame();
2417 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2418 f = f.sender(&map);
2419 }
2420 if (f.id() == thread->must_deopt_id()) {
2421 thread->clear_must_deopt_id();
2422 f.deoptimize(thread);
2423 } else {
2424 fatal("missed deoptimization!");
2425 }
2426 }
2427 }
2428
2429 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2430 // progress or when _suspend_flags is non-zero.
2431 // Current thread needs to self-suspend if there is a suspend request and/or
2432 // block if a safepoint is in progress.
2433 // Also check for pending async exception (not including unsafe access error).
2434 // Note only the native==>VM/Java barriers can call this function and when
2435 // thread state is _thread_in_native_trans.
2436 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2437 check_safepoint_and_suspend_for_native_trans(thread);
2438
2439 if (thread->has_async_exception()) {
2440 // We are in _thread_in_native_trans state, don't handle unsafe
2441 // access error since that may block.
2442 thread->check_and_handle_async_exceptions(false);
2443 }
2444 }
2445
2446 // This is a variant of the normal
2447 // check_special_condition_for_native_trans with slightly different
2448 // semantics for use by critical native wrappers. It does all the
2449 // normal checks but also performs the transition back into
2450 // thread_in_Java state. This is required so that critical natives
2451 // can potentially block and perform a GC if they are the last thread
2452 // exiting the GC_locker.
2453 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2454 check_special_condition_for_native_trans(thread);
2455
2456 // Finish the transition
2457 thread->set_thread_state(_thread_in_Java);
2458
2459 if (thread->do_critical_native_unlock()) {
2460 ThreadInVMfromJavaNoAsyncException tiv(thread);
2461 GC_locker::unlock_critical(thread);
2462 thread->clear_critical_native_unlock();
2463 }
2464 }
2465
2466 // We need to guarantee the Threads_lock here, since resumes are not
2467 // allowed during safepoint synchronization
2468 // Can only resume from an external suspension
2469 void JavaThread::java_resume() {
2470 assert_locked_or_safepoint(Threads_lock);
2471
2472 // Sanity check: thread is gone, has started exiting or the thread
2473 // was not externally suspended.
2474 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2475 return;
2476 }
2477
2478 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2479
2480 clear_external_suspend();
2481
2482 if (is_ext_suspended()) {
2483 clear_ext_suspended();
2484 SR_lock()->notify_all();
2485 }
2486 }
2487
2488 void JavaThread::create_stack_guard_pages() {
2489 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2490 address low_addr = stack_base() - stack_size();
2491 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2492
2493 int allocate = os::allocate_stack_guard_pages();
2494 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2495
2496 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2497 warning("Attempt to allocate stack guard pages failed.");
2498 return;
2499 }
2500
2501 if (os::guard_memory((char *) low_addr, len)) {
2502 _stack_guard_state = stack_guard_enabled;
2503 } else {
2504 warning("Attempt to protect stack guard pages failed.");
2505 if (os::uncommit_memory((char *) low_addr, len)) {
2506 warning("Attempt to deallocate stack guard pages failed.");
2507 }
2508 }
2509 }
2510
2511 void JavaThread::remove_stack_guard_pages() {
2512 assert(Thread::current() == this, "from different thread");
2513 if (_stack_guard_state == stack_guard_unused) return;
2514 address low_addr = stack_base() - stack_size();
2515 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2516
2517 if (os::allocate_stack_guard_pages()) {
2518 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2519 _stack_guard_state = stack_guard_unused;
2520 } else {
2521 warning("Attempt to deallocate stack guard pages failed.");
2522 }
2523 } else {
2524 if (_stack_guard_state == stack_guard_unused) return;
2525 if (os::unguard_memory((char *) low_addr, len)) {
2526 _stack_guard_state = stack_guard_unused;
2527 } else {
2528 warning("Attempt to unprotect stack guard pages failed.");
2529 }
2530 }
2531 }
2532
2533 void JavaThread::enable_stack_yellow_zone() {
2534 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2535 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2536
2537 // The base notation is from the stacks point of view, growing downward.
2538 // We need to adjust it to work correctly with guard_memory()
2539 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2540
2541 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2542 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2543
2544 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2545 _stack_guard_state = stack_guard_enabled;
2546 } else {
2547 warning("Attempt to guard stack yellow zone failed.");
2548 }
2549 enable_register_stack_guard();
2550 }
2551
2552 void JavaThread::disable_stack_yellow_zone() {
2553 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2554 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2555
2556 // Simply return if called for a thread that does not use guard pages.
2557 if (_stack_guard_state == stack_guard_unused) return;
2558
2559 // The base notation is from the stacks point of view, growing downward.
2560 // We need to adjust it to work correctly with guard_memory()
2561 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2562
2563 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2564 _stack_guard_state = stack_guard_yellow_disabled;
2565 } else {
2566 warning("Attempt to unguard stack yellow zone failed.");
2567 }
2568 disable_register_stack_guard();
2569 }
2570
2571 void JavaThread::enable_stack_red_zone() {
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 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2575 address base = stack_red_zone_base() - stack_red_zone_size();
2576
2577 guarantee(base < stack_base(),"Error calculating stack red zone");
2578 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2579
2580 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2581 warning("Attempt to guard stack red zone failed.");
2582 }
2583 }
2584
2585 void JavaThread::disable_stack_red_zone() {
2586 // The base notation is from the stacks point of view, growing downward.
2587 // We need to adjust it to work correctly with guard_memory()
2588 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2589 address base = stack_red_zone_base() - stack_red_zone_size();
2590 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2591 warning("Attempt to unguard stack red zone failed.");
2592 }
2593 }
2594
2595 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2596 // ignore is there is no stack
2597 if (!has_last_Java_frame()) return;
2598 // traverse the stack frames. Starts from top frame.
2599 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2600 frame* fr = fst.current();
2601 f(fr, fst.register_map());
2602 }
2603 }
2604
2605
2606 #ifndef PRODUCT
2607 // Deoptimization
2608 // Function for testing deoptimization
2609 void JavaThread::deoptimize() {
2610 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2611 StackFrameStream fst(this, UseBiasedLocking);
2612 bool deopt = false; // Dump stack only if a deopt actually happens.
2613 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2614 // Iterate over all frames in the thread and deoptimize
2615 for(; !fst.is_done(); fst.next()) {
2616 if(fst.current()->can_be_deoptimized()) {
2617
2618 if (only_at) {
2619 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2620 // consists of comma or carriage return separated numbers so
2621 // search for the current bci in that string.
2622 address pc = fst.current()->pc();
2623 nmethod* nm = (nmethod*) fst.current()->cb();
2624 ScopeDesc* sd = nm->scope_desc_at( pc);
2625 char buffer[8];
2626 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2627 size_t len = strlen(buffer);
2628 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2629 while (found != NULL) {
2630 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2631 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2632 // Check that the bci found is bracketed by terminators.
2633 break;
2634 }
2635 found = strstr(found + 1, buffer);
2636 }
2637 if (!found) {
2638 continue;
2639 }
2640 }
2641
2642 if (DebugDeoptimization && !deopt) {
2643 deopt = true; // One-time only print before deopt
2644 tty->print_cr("[BEFORE Deoptimization]");
2645 trace_frames();
2646 trace_stack();
2647 }
2648 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2649 }
2650 }
2651
2652 if (DebugDeoptimization && deopt) {
2653 tty->print_cr("[AFTER Deoptimization]");
2654 trace_frames();
2655 }
2656 }
2657
2658
2659 // Make zombies
2660 void JavaThread::make_zombies() {
2661 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2662 if (fst.current()->can_be_deoptimized()) {
2663 // it is a Java nmethod
2664 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2665 nm->make_not_entrant();
2666 }
2667 }
2668 }
2669 #endif // PRODUCT
2670
2671
2672 void JavaThread::deoptimized_wrt_marked_nmethods() {
2673 if (!has_last_Java_frame()) return;
2674 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2675 StackFrameStream fst(this, UseBiasedLocking);
2676 for(; !fst.is_done(); fst.next()) {
2677 if (fst.current()->should_be_deoptimized()) {
2678 if (LogCompilation && xtty != NULL) {
2679 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2680 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2681 this->name(), nm != NULL ? nm->compile_id() : -1);
2682 }
2683
2684 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2685 }
2686 }
2687 }
2688
2689
2690 // GC support
2691 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2692
2693 void JavaThread::gc_epilogue() {
2694 frames_do(frame_gc_epilogue);
2695 }
2696
2697
2698 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2699
2700 void JavaThread::gc_prologue() {
2701 frames_do(frame_gc_prologue);
2702 }
2703
2704 // If the caller is a NamedThread, then remember, in the current scope,
2705 // the given JavaThread in its _processed_thread field.
2706 class RememberProcessedThread: public StackObj {
2707 NamedThread* _cur_thr;
2708 public:
2709 RememberProcessedThread(JavaThread* jthr) {
2710 Thread* thread = Thread::current();
2711 if (thread->is_Named_thread()) {
2712 _cur_thr = (NamedThread *)thread;
2713 _cur_thr->set_processed_thread(jthr);
2714 } else {
2715 _cur_thr = NULL;
2716 }
2717 }
2718
2719 ~RememberProcessedThread() {
2720 if (_cur_thr) {
2721 _cur_thr->set_processed_thread(NULL);
2722 }
2723 }
2724 };
2725
2726 void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
2727 // Verify that the deferred card marks have been flushed.
2728 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2729
2730 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2731 // since there may be more than one thread using each ThreadProfiler.
2732
2733 // Traverse the GCHandles
2734 Thread::oops_do(f, cld_f, cf);
2735
2736 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2737 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2738
2739 if (has_last_Java_frame()) {
2740 // Record JavaThread to GC thread
2741 RememberProcessedThread rpt(this);
2742
2743 // Traverse the privileged stack
2744 if (_privileged_stack_top != NULL) {
2745 _privileged_stack_top->oops_do(f);
2746 }
2747
2748 // traverse the registered growable array
2749 if (_array_for_gc != NULL) {
2750 for (int index = 0; index < _array_for_gc->length(); index++) {
2751 f->do_oop(_array_for_gc->adr_at(index));
2752 }
2753 }
2754
2755 // Traverse the monitor chunks
2756 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2757 chunk->oops_do(f);
2758 }
2759
2760 // Traverse the execution stack
2761 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2762 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2763 }
2764 }
2765
2766 // callee_target is never live across a gc point so NULL it here should
2767 // it still contain a methdOop.
2768
2769 set_callee_target(NULL);
2770
2771 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2772 // If we have deferred set_locals there might be oops waiting to be
2773 // written
2774 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2775 if (list != NULL) {
2776 for (int i = 0; i < list->length(); i++) {
2777 list->at(i)->oops_do(f);
2778 }
2779 }
2780
2781 // Traverse instance variables at the end since the GC may be moving things
2782 // around using this function
2783 f->do_oop((oop*) &_threadObj);
2784 f->do_oop((oop*) &_vm_result);
2785 f->do_oop((oop*) &_exception_oop);
2786 f->do_oop((oop*) &_pending_async_exception);
2787
2788 if (jvmti_thread_state() != NULL) {
2789 jvmti_thread_state()->oops_do(f);
2790 }
2791 }
2792
2793 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2794 Thread::nmethods_do(cf); // (super method is a no-op)
2795
2796 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2797 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2798
2799 if (has_last_Java_frame()) {
2800 // Traverse the execution stack
2801 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2802 fst.current()->nmethods_do(cf);
2803 }
2804 }
2805 }
2806
2807 void JavaThread::metadata_do(void f(Metadata*)) {
2808 Thread::metadata_do(f);
2809 if (has_last_Java_frame()) {
2810 // Traverse the execution stack to call f() on the methods in the stack
2811 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2812 fst.current()->metadata_do(f);
2813 }
2814 } else if (is_Compiler_thread()) {
2815 // need to walk ciMetadata in current compile tasks to keep alive.
2816 CompilerThread* ct = (CompilerThread*)this;
2817 if (ct->env() != NULL) {
2818 ct->env()->metadata_do(f);
2819 }
2820 }
2821 }
2822
2823 // Printing
2824 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2825 switch (_thread_state) {
2826 case _thread_uninitialized: return "_thread_uninitialized";
2827 case _thread_new: return "_thread_new";
2828 case _thread_new_trans: return "_thread_new_trans";
2829 case _thread_in_native: return "_thread_in_native";
2830 case _thread_in_native_trans: return "_thread_in_native_trans";
2831 case _thread_in_vm: return "_thread_in_vm";
2832 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2833 case _thread_in_Java: return "_thread_in_Java";
2834 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2835 case _thread_blocked: return "_thread_blocked";
2836 case _thread_blocked_trans: return "_thread_blocked_trans";
2837 default: return "unknown thread state";
2838 }
2839 }
2840
2841 #ifndef PRODUCT
2842 void JavaThread::print_thread_state_on(outputStream *st) const {
2843 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2844 };
2845 void JavaThread::print_thread_state() const {
2846 print_thread_state_on(tty);
2847 };
2848 #endif // PRODUCT
2849
2850 // Called by Threads::print() for VM_PrintThreads operation
2851 void JavaThread::print_on(outputStream *st) const {
2852 st->print("\"%s\" ", get_thread_name());
2853 oop thread_oop = threadObj();
2854 if (thread_oop != NULL) {
2855 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2856 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2857 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2858 }
2859 Thread::print_on(st);
2860 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2861 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2862 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2863 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2864 }
2865 #ifndef PRODUCT
2866 print_thread_state_on(st);
2867 _safepoint_state->print_on(st);
2868 #endif // PRODUCT
2869 }
2870
2871 // Called by fatal error handler. The difference between this and
2872 // JavaThread::print() is that we can't grab lock or allocate memory.
2873 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2874 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2875 oop thread_obj = threadObj();
2876 if (thread_obj != NULL) {
2877 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2878 }
2879 st->print(" [");
2880 st->print("%s", _get_thread_state_name(_thread_state));
2881 if (osthread()) {
2882 st->print(", id=%d", osthread()->thread_id());
2883 }
2884 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2885 _stack_base - _stack_size, _stack_base);
2886 st->print("]");
2887 return;
2888 }
2889
2890 // Verification
2891
2892 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2893
2894 void JavaThread::verify() {
2895 // Verify oops in the thread.
2896 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2897
2898 // Verify the stack frames.
2899 frames_do(frame_verify);
2900 }
2901
2902 // CR 6300358 (sub-CR 2137150)
2903 // Most callers of this method assume that it can't return NULL but a
2904 // thread may not have a name whilst it is in the process of attaching to
2905 // the VM - see CR 6412693, and there are places where a JavaThread can be
2906 // seen prior to having it's threadObj set (eg JNI attaching threads and
2907 // if vm exit occurs during initialization). These cases can all be accounted
2908 // for such that this method never returns NULL.
2909 const char* JavaThread::get_thread_name() const {
2910 #ifdef ASSERT
2911 // early safepoints can hit while current thread does not yet have TLS
2912 if (!SafepointSynchronize::is_at_safepoint()) {
2913 Thread *cur = Thread::current();
2914 if (!(cur->is_Java_thread() && cur == this)) {
2915 // Current JavaThreads are allowed to get their own name without
2916 // the Threads_lock.
2917 assert_locked_or_safepoint(Threads_lock);
2918 }
2919 }
2920 #endif // ASSERT
2921 return get_thread_name_string();
2922 }
2923
2924 // Returns a non-NULL representation of this thread's name, or a suitable
2925 // descriptive string if there is no set name
2926 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2927 const char* name_str;
2928 oop thread_obj = threadObj();
2929 if (thread_obj != NULL) {
2930 typeArrayOop name = java_lang_Thread::name(thread_obj);
2931 if (name != NULL) {
2932 if (buf == NULL) {
2933 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2934 }
2935 else {
2936 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2937 }
2938 }
2939 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2940 name_str = "<no-name - thread is attaching>";
2941 }
2942 else {
2943 name_str = Thread::name();
2944 }
2945 }
2946 else {
2947 name_str = Thread::name();
2948 }
2949 assert(name_str != NULL, "unexpected NULL thread name");
2950 return name_str;
2951 }
2952
2953
2954 const char* JavaThread::get_threadgroup_name() const {
2955 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2956 oop thread_obj = threadObj();
2957 if (thread_obj != NULL) {
2958 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2959 if (thread_group != NULL) {
2960 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2961 // ThreadGroup.name can be null
2962 if (name != NULL) {
2963 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2964 return str;
2965 }
2966 }
2967 }
2968 return NULL;
2969 }
2970
2971 const char* JavaThread::get_parent_name() const {
2972 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2973 oop thread_obj = threadObj();
2974 if (thread_obj != NULL) {
2975 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2976 if (thread_group != NULL) {
2977 oop parent = java_lang_ThreadGroup::parent(thread_group);
2978 if (parent != NULL) {
2979 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2980 // ThreadGroup.name can be null
2981 if (name != NULL) {
2982 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2983 return str;
2984 }
2985 }
2986 }
2987 }
2988 return NULL;
2989 }
2990
2991 ThreadPriority JavaThread::java_priority() const {
2992 oop thr_oop = threadObj();
2993 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2994 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2995 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2996 return priority;
2997 }
2998
2999 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3000
3001 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3002 // Link Java Thread object <-> C++ Thread
3003
3004 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3005 // and put it into a new Handle. The Handle "thread_oop" can then
3006 // be used to pass the C++ thread object to other methods.
3007
3008 // Set the Java level thread object (jthread) field of the
3009 // new thread (a JavaThread *) to C++ thread object using the
3010 // "thread_oop" handle.
3011
3012 // Set the thread field (a JavaThread *) of the
3013 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3014
3015 Handle thread_oop(Thread::current(),
3016 JNIHandles::resolve_non_null(jni_thread));
3017 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3018 "must be initialized");
3019 set_threadObj(thread_oop());
3020 java_lang_Thread::set_thread(thread_oop(), this);
3021
3022 if (prio == NoPriority) {
3023 prio = java_lang_Thread::priority(thread_oop());
3024 assert(prio != NoPriority, "A valid priority should be present");
3025 }
3026
3027 // Push the Java priority down to the native thread; needs Threads_lock
3028 Thread::set_priority(this, prio);
3029
3030 // Add the new thread to the Threads list and set it in motion.
3031 // We must have threads lock in order to call Threads::add.
3032 // It is crucial that we do not block before the thread is
3033 // added to the Threads list for if a GC happens, then the java_thread oop
3034 // will not be visited by GC.
3035 Threads::add(this);
3036 }
3037
3038 oop JavaThread::current_park_blocker() {
3039 // Support for JSR-166 locks
3040 oop thread_oop = threadObj();
3041 if (thread_oop != NULL &&
3042 JDK_Version::current().supports_thread_park_blocker()) {
3043 return java_lang_Thread::park_blocker(thread_oop);
3044 }
3045 return NULL;
3046 }
3047
3048
3049 void JavaThread::print_stack_on(outputStream* st) {
3050 if (!has_last_Java_frame()) return;
3051 ResourceMark rm;
3052 HandleMark hm;
3053
3054 RegisterMap reg_map(this);
3055 vframe* start_vf = last_java_vframe(®_map);
3056 int count = 0;
3057 for (vframe* f = start_vf; f; f = f->sender() ) {
3058 if (f->is_java_frame()) {
3059 javaVFrame* jvf = javaVFrame::cast(f);
3060 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3061
3062 // Print out lock information
3063 if (JavaMonitorsInStackTrace) {
3064 jvf->print_lock_info_on(st, count);
3065 }
3066 } else {
3067 // Ignore non-Java frames
3068 }
3069
3070 // Bail-out case for too deep stacks
3071 count++;
3072 if (MaxJavaStackTraceDepth == count) return;
3073 }
3074 }
3075
3076
3077 // JVMTI PopFrame support
3078 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3079 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3080 if (in_bytes(size_in_bytes) != 0) {
3081 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3082 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3083 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3084 }
3085 }
3086
3087 void* JavaThread::popframe_preserved_args() {
3088 return _popframe_preserved_args;
3089 }
3090
3091 ByteSize JavaThread::popframe_preserved_args_size() {
3092 return in_ByteSize(_popframe_preserved_args_size);
3093 }
3094
3095 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3096 int sz = in_bytes(popframe_preserved_args_size());
3097 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3098 return in_WordSize(sz / wordSize);
3099 }
3100
3101 void JavaThread::popframe_free_preserved_args() {
3102 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3103 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3104 _popframe_preserved_args = NULL;
3105 _popframe_preserved_args_size = 0;
3106 }
3107
3108 #ifndef PRODUCT
3109
3110 void JavaThread::trace_frames() {
3111 tty->print_cr("[Describe stack]");
3112 int frame_no = 1;
3113 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3114 tty->print(" %d. ", frame_no++);
3115 fst.current()->print_value_on(tty,this);
3116 tty->cr();
3117 }
3118 }
3119
3120 class PrintAndVerifyOopClosure: public OopClosure {
3121 protected:
3122 template <class T> inline void do_oop_work(T* p) {
3123 oop obj = oopDesc::load_decode_heap_oop(p);
3124 if (obj == NULL) return;
3125 tty->print(INTPTR_FORMAT ": ", p);
3126 if (obj->is_oop_or_null()) {
3127 if (obj->is_objArray()) {
3128 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3129 } else {
3130 obj->print();
3131 }
3132 } else {
3133 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3134 }
3135 tty->cr();
3136 }
3137 public:
3138 virtual void do_oop(oop* p) { do_oop_work(p); }
3139 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3140 };
3141
3142
3143 static void oops_print(frame* f, const RegisterMap *map) {
3144 PrintAndVerifyOopClosure print;
3145 f->print_value();
3146 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3147 }
3148
3149 // Print our all the locations that contain oops and whether they are
3150 // valid or not. This useful when trying to find the oldest frame
3151 // where an oop has gone bad since the frame walk is from youngest to
3152 // oldest.
3153 void JavaThread::trace_oops() {
3154 tty->print_cr("[Trace oops]");
3155 frames_do(oops_print);
3156 }
3157
3158
3159 #ifdef ASSERT
3160 // Print or validate the layout of stack frames
3161 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3162 ResourceMark rm;
3163 PRESERVE_EXCEPTION_MARK;
3164 FrameValues values;
3165 int frame_no = 0;
3166 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3167 fst.current()->describe(values, ++frame_no);
3168 if (depth == frame_no) break;
3169 }
3170 if (validate_only) {
3171 values.validate();
3172 } else {
3173 tty->print_cr("[Describe stack layout]");
3174 values.print(this);
3175 }
3176 }
3177 #endif
3178
3179 void JavaThread::trace_stack_from(vframe* start_vf) {
3180 ResourceMark rm;
3181 int vframe_no = 1;
3182 for (vframe* f = start_vf; f; f = f->sender() ) {
3183 if (f->is_java_frame()) {
3184 javaVFrame::cast(f)->print_activation(vframe_no++);
3185 } else {
3186 f->print();
3187 }
3188 if (vframe_no > StackPrintLimit) {
3189 tty->print_cr("...<more frames>...");
3190 return;
3191 }
3192 }
3193 }
3194
3195
3196 void JavaThread::trace_stack() {
3197 if (!has_last_Java_frame()) return;
3198 ResourceMark rm;
3199 HandleMark hm;
3200 RegisterMap reg_map(this);
3201 trace_stack_from(last_java_vframe(®_map));
3202 }
3203
3204
3205 #endif // PRODUCT
3206
3207
3208 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3209 assert(reg_map != NULL, "a map must be given");
3210 frame f = last_frame();
3211 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3212 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3213 }
3214 return NULL;
3215 }
3216
3217
3218 Klass* JavaThread::security_get_caller_class(int depth) {
3219 vframeStream vfst(this);
3220 vfst.security_get_caller_frame(depth);
3221 if (!vfst.at_end()) {
3222 return vfst.method()->method_holder();
3223 }
3224 return NULL;
3225 }
3226
3227 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3228 assert(thread->is_Compiler_thread(), "must be compiler thread");
3229 CompileBroker::compiler_thread_loop();
3230 }
3231
3232 // Create a CompilerThread
3233 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3234 : JavaThread(&compiler_thread_entry) {
3235 _env = NULL;
3236 _log = NULL;
3237 _task = NULL;
3238 _queue = queue;
3239 _counters = counters;
3240 _buffer_blob = NULL;
3241 _scanned_nmethod = NULL;
3242
3243 #ifndef PRODUCT
3244 _ideal_graph_printer = NULL;
3245 #endif
3246 }
3247
3248 void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
3249 JavaThread::oops_do(f, cld_f, cf);
3250 if (_scanned_nmethod != NULL && cf != NULL) {
3251 // Safepoints can occur when the sweeper is scanning an nmethod so
3252 // process it here to make sure it isn't unloaded in the middle of
3253 // a scan.
3254 cf->do_code_blob(_scanned_nmethod);
3255 }
3256 }
3257
3258 // ======= Threads ========
3259
3260 // The Threads class links together all active threads, and provides
3261 // operations over all threads. It is protected by its own Mutex
3262 // lock, which is also used in other contexts to protect thread
3263 // operations from having the thread being operated on from exiting
3264 // and going away unexpectedly (e.g., safepoint synchronization)
3265
3266 JavaThread* Threads::_thread_list = NULL;
3267 int Threads::_number_of_threads = 0;
3268 int Threads::_number_of_non_daemon_threads = 0;
3269 int Threads::_return_code = 0;
3270 size_t JavaThread::_stack_size_at_create = 0;
3271 #ifdef ASSERT
3272 bool Threads::_vm_complete = false;
3273 #endif
3274
3275 // All JavaThreads
3276 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3277
3278 void os_stream();
3279
3280 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3281 void Threads::threads_do(ThreadClosure* tc) {
3282 assert_locked_or_safepoint(Threads_lock);
3283 // ALL_JAVA_THREADS iterates through all JavaThreads
3284 ALL_JAVA_THREADS(p) {
3285 tc->do_thread(p);
3286 }
3287 // Someday we could have a table or list of all non-JavaThreads.
3288 // For now, just manually iterate through them.
3289 tc->do_thread(VMThread::vm_thread());
3290 Universe::heap()->gc_threads_do(tc);
3291 WatcherThread *wt = WatcherThread::watcher_thread();
3292 // Strictly speaking, the following NULL check isn't sufficient to make sure
3293 // the data for WatcherThread is still valid upon being examined. However,
3294 // considering that WatchThread terminates when the VM is on the way to
3295 // exit at safepoint, the chance of the above is extremely small. The right
3296 // way to prevent termination of WatcherThread would be to acquire
3297 // Terminator_lock, but we can't do that without violating the lock rank
3298 // checking in some cases.
3299 if (wt != NULL)
3300 tc->do_thread(wt);
3301
3302 // If CompilerThreads ever become non-JavaThreads, add them here
3303 }
3304
3305 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3306
3307 extern void JDK_Version_init();
3308
3309 // Check version
3310 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3311
3312 // Initialize the output stream module
3313 ostream_init();
3314
3315 // Process java launcher properties.
3316 Arguments::process_sun_java_launcher_properties(args);
3317
3318 // Initialize the os module before using TLS
3319 os::init();
3320
3321 // Initialize system properties.
3322 Arguments::init_system_properties();
3323
3324 // So that JDK version can be used as a discrimintor when parsing arguments
3325 JDK_Version_init();
3326
3327 // Update/Initialize System properties after JDK version number is known
3328 Arguments::init_version_specific_system_properties();
3329
3330 // Parse arguments
3331 jint parse_result = Arguments::parse(args);
3332 if (parse_result != JNI_OK) return parse_result;
3333
3334 os::init_before_ergo();
3335
3336 jint ergo_result = Arguments::apply_ergo();
3337 if (ergo_result != JNI_OK) return ergo_result;
3338
3339 if (PauseAtStartup) {
3340 os::pause();
3341 }
3342
3343 #ifndef USDT2
3344 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3345 #else /* USDT2 */
3346 HOTSPOT_VM_INIT_BEGIN();
3347 #endif /* USDT2 */
3348
3349 // Record VM creation timing statistics
3350 TraceVmCreationTime create_vm_timer;
3351 create_vm_timer.start();
3352
3353 // Timing (must come after argument parsing)
3354 TraceTime timer("Create VM", TraceStartupTime);
3355
3356 // Initialize the os module after parsing the args
3357 jint os_init_2_result = os::init_2();
3358 if (os_init_2_result != JNI_OK) return os_init_2_result;
3359
3360 jint adjust_after_os_result = Arguments::adjust_after_os();
3361 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3362
3363 // intialize TLS
3364 ThreadLocalStorage::init();
3365
3366 // Bootstrap native memory tracking, so it can start recording memory
3367 // activities before worker thread is started. This is the first phase
3368 // of bootstrapping, VM is currently running in single-thread mode.
3369 MemTracker::bootstrap_single_thread();
3370
3371 // Initialize output stream logging
3372 ostream_init_log();
3373
3374 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3375 // Must be before create_vm_init_agents()
3376 if (Arguments::init_libraries_at_startup()) {
3377 convert_vm_init_libraries_to_agents();
3378 }
3379
3380 // Launch -agentlib/-agentpath and converted -Xrun agents
3381 if (Arguments::init_agents_at_startup()) {
3382 create_vm_init_agents();
3383 }
3384
3385 // Initialize Threads state
3386 _thread_list = NULL;
3387 _number_of_threads = 0;
3388 _number_of_non_daemon_threads = 0;
3389
3390 // Initialize global data structures and create system classes in heap
3391 vm_init_globals();
3392
3393 // Attach the main thread to this os thread
3394 JavaThread* main_thread = new JavaThread();
3395 main_thread->set_thread_state(_thread_in_vm);
3396 // must do this before set_active_handles and initialize_thread_local_storage
3397 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3398 // change the stack size recorded here to one based on the java thread
3399 // stacksize. This adjusted size is what is used to figure the placement
3400 // of the guard pages.
3401 main_thread->record_stack_base_and_size();
3402 main_thread->initialize_thread_local_storage();
3403
3404 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3405
3406 if (!main_thread->set_as_starting_thread()) {
3407 vm_shutdown_during_initialization(
3408 "Failed necessary internal allocation. Out of swap space");
3409 delete main_thread;
3410 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3411 return JNI_ENOMEM;
3412 }
3413
3414 // Enable guard page *after* os::create_main_thread(), otherwise it would
3415 // crash Linux VM, see notes in os_linux.cpp.
3416 main_thread->create_stack_guard_pages();
3417
3418 // Initialize Java-Level synchronization subsystem
3419 ObjectMonitor::Initialize() ;
3420
3421 // Second phase of bootstrapping, VM is about entering multi-thread mode
3422 MemTracker::bootstrap_multi_thread();
3423
3424 // Initialize global modules
3425 jint status = init_globals();
3426 if (status != JNI_OK) {
3427 delete main_thread;
3428 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3429 return status;
3430 }
3431
3432 // Should be done after the heap is fully created
3433 main_thread->cache_global_variables();
3434
3435 HandleMark hm;
3436
3437 { MutexLocker mu(Threads_lock);
3438 Threads::add(main_thread);
3439 }
3440
3441 // Any JVMTI raw monitors entered in onload will transition into
3442 // real raw monitor. VM is setup enough here for raw monitor enter.
3443 JvmtiExport::transition_pending_onload_raw_monitors();
3444
3445 // Fully start NMT
3446 MemTracker::start();
3447
3448 // Create the VMThread
3449 { TraceTime timer("Start VMThread", TraceStartupTime);
3450 VMThread::create();
3451 Thread* vmthread = VMThread::vm_thread();
3452
3453 if (!os::create_thread(vmthread, os::vm_thread))
3454 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3455
3456 // Wait for the VM thread to become ready, and VMThread::run to initialize
3457 // Monitors can have spurious returns, must always check another state flag
3458 {
3459 MutexLocker ml(Notify_lock);
3460 os::start_thread(vmthread);
3461 while (vmthread->active_handles() == NULL) {
3462 Notify_lock->wait();
3463 }
3464 }
3465 }
3466
3467 assert (Universe::is_fully_initialized(), "not initialized");
3468 if (VerifyDuringStartup) {
3469 // Make sure we're starting with a clean slate.
3470 VM_Verify verify_op;
3471 VMThread::execute(&verify_op);
3472 }
3473
3474 EXCEPTION_MARK;
3475
3476 // At this point, the Universe is initialized, but we have not executed
3477 // any byte code. Now is a good time (the only time) to dump out the
3478 // internal state of the JVM for sharing.
3479 if (DumpSharedSpaces) {
3480 MetaspaceShared::preload_and_dump(CHECK_0);
3481 ShouldNotReachHere();
3482 }
3483
3484 // Always call even when there are not JVMTI environments yet, since environments
3485 // may be attached late and JVMTI must track phases of VM execution
3486 JvmtiExport::enter_start_phase();
3487
3488 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3489 JvmtiExport::post_vm_start();
3490
3491 {
3492 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3493
3494 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3495 create_vm_init_libraries();
3496 }
3497
3498 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3499
3500 // Initialize java_lang.System (needed before creating the thread)
3501 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3502 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3503 Handle thread_group = create_initial_thread_group(CHECK_0);
3504 Universe::set_main_thread_group(thread_group());
3505 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3506 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3507 main_thread->set_threadObj(thread_object);
3508 // Set thread status to running since main thread has
3509 // been started and running.
3510 java_lang_Thread::set_thread_status(thread_object,
3511 java_lang_Thread::RUNNABLE);
3512
3513 // The VM creates & returns objects of this class. Make sure it's initialized.
3514 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3515
3516 // The VM preresolves methods to these classes. Make sure that they get initialized
3517 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3518 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3519 call_initializeSystemClass(CHECK_0);
3520
3521 // get the Java runtime name after java.lang.System is initialized
3522 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3523 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3524
3525 // an instance of OutOfMemory exception has been allocated earlier
3526 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3527 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3528 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3529 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3530 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3531 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3532 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3533 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3534 }
3535
3536 // See : bugid 4211085.
3537 // Background : the static initializer of java.lang.Compiler tries to read
3538 // property"java.compiler" and read & write property "java.vm.info".
3539 // When a security manager is installed through the command line
3540 // option "-Djava.security.manager", the above properties are not
3541 // readable and the static initializer for java.lang.Compiler fails
3542 // resulting in a NoClassDefFoundError. This can happen in any
3543 // user code which calls methods in java.lang.Compiler.
3544 // Hack : the hack is to pre-load and initialize this class, so that only
3545 // system domains are on the stack when the properties are read.
3546 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3547 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3548 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3549 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3550 // Once that is done, we should remove this hack.
3551 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3552
3553 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3554 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3555 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3556 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3557 // This should also be taken out as soon as 4211383 gets fixed.
3558 reset_vm_info_property(CHECK_0);
3559
3560 quicken_jni_functions();
3561
3562 // Must be run after init_ft which initializes ft_enabled
3563 if (TRACE_INITIALIZE() != JNI_OK) {
3564 vm_exit_during_initialization("Failed to initialize tracing backend");
3565 }
3566
3567 // Set flag that basic initialization has completed. Used by exceptions and various
3568 // debug stuff, that does not work until all basic classes have been initialized.
3569 set_init_completed();
3570
3571 #ifndef USDT2
3572 HS_DTRACE_PROBE(hotspot, vm__init__end);
3573 #else /* USDT2 */
3574 HOTSPOT_VM_INIT_END();
3575 #endif /* USDT2 */
3576
3577 // record VM initialization completion time
3578 #if INCLUDE_MANAGEMENT
3579 Management::record_vm_init_completed();
3580 #endif // INCLUDE_MANAGEMENT
3581
3582 // Compute system loader. Note that this has to occur after set_init_completed, since
3583 // valid exceptions may be thrown in the process.
3584 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3585 // set_init_completed has just been called, causing exceptions not to be shortcut
3586 // anymore. We call vm_exit_during_initialization directly instead.
3587 SystemDictionary::compute_java_system_loader(THREAD);
3588 if (HAS_PENDING_EXCEPTION) {
3589 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3590 }
3591
3592 #if INCLUDE_ALL_GCS
3593 // Support for ConcurrentMarkSweep. This should be cleaned up
3594 // and better encapsulated. The ugly nested if test would go away
3595 // once things are properly refactored. XXX YSR
3596 if (UseConcMarkSweepGC || UseG1GC) {
3597 if (UseConcMarkSweepGC) {
3598 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3599 } else {
3600 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3601 }
3602 if (HAS_PENDING_EXCEPTION) {
3603 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3604 }
3605 }
3606 #endif // INCLUDE_ALL_GCS
3607
3608 // Always call even when there are not JVMTI environments yet, since environments
3609 // may be attached late and JVMTI must track phases of VM execution
3610 JvmtiExport::enter_live_phase();
3611
3612 // Signal Dispatcher needs to be started before VMInit event is posted
3613 os::signal_init();
3614
3615 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3616 if (!DisableAttachMechanism) {
3617 AttachListener::vm_start();
3618 if (StartAttachListener || AttachListener::init_at_startup()) {
3619 AttachListener::init();
3620 }
3621 }
3622
3623 // Launch -Xrun agents
3624 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3625 // back-end can launch with -Xdebug -Xrunjdwp.
3626 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3627 create_vm_init_libraries();
3628 }
3629
3630 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3631 JvmtiExport::post_vm_initialized();
3632
3633 if (TRACE_START() != JNI_OK) {
3634 vm_exit_during_initialization("Failed to start tracing backend.");
3635 }
3636
3637 if (CleanChunkPoolAsync) {
3638 Chunk::start_chunk_pool_cleaner_task();
3639 }
3640
3641 // initialize compiler(s)
3642 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3643 CompileBroker::compilation_init();
3644 #endif
3645
3646 if (EnableInvokeDynamic) {
3647 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3648 // It is done after compilers are initialized, because otherwise compilations of
3649 // signature polymorphic MH intrinsics can be missed
3650 // (see SystemDictionary::find_method_handle_intrinsic).
3651 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3652 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3653 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3654 }
3655
3656 #if INCLUDE_MANAGEMENT
3657 Management::initialize(THREAD);
3658 #endif // INCLUDE_MANAGEMENT
3659
3660 if (HAS_PENDING_EXCEPTION) {
3661 // management agent fails to start possibly due to
3662 // configuration problem and is responsible for printing
3663 // stack trace if appropriate. Simply exit VM.
3664 vm_exit(1);
3665 }
3666
3667 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3668 if (MemProfiling) MemProfiler::engage();
3669 StatSampler::engage();
3670 if (CheckJNICalls) JniPeriodicChecker::engage();
3671
3672 BiasedLocking::init();
3673
3674 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3675 call_postVMInitHook(THREAD);
3676 // The Java side of PostVMInitHook.run must deal with all
3677 // exceptions and provide means of diagnosis.
3678 if (HAS_PENDING_EXCEPTION) {
3679 CLEAR_PENDING_EXCEPTION;
3680 }
3681 }
3682
3683 {
3684 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3685 // Make sure the watcher thread can be started by WatcherThread::start()
3686 // or by dynamic enrollment.
3687 WatcherThread::make_startable();
3688 // Start up the WatcherThread if there are any periodic tasks
3689 // NOTE: All PeriodicTasks should be registered by now. If they
3690 // aren't, late joiners might appear to start slowly (we might
3691 // take a while to process their first tick).
3692 if (PeriodicTask::num_tasks() > 0) {
3693 WatcherThread::start();
3694 }
3695 }
3696
3697 // Give os specific code one last chance to start
3698 os::init_3();
3699
3700 create_vm_timer.end();
3701 #ifdef ASSERT
3702 _vm_complete = true;
3703 #endif
3704 return JNI_OK;
3705 }
3706
3707 // type for the Agent_OnLoad and JVM_OnLoad entry points
3708 extern "C" {
3709 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3710 }
3711 // Find a command line agent library and return its entry point for
3712 // -agentlib: -agentpath: -Xrun
3713 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3714 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3715 OnLoadEntry_t on_load_entry = NULL;
3716 void *library = NULL;
3717
3718 if (!agent->valid()) {
3719 char buffer[JVM_MAXPATHLEN];
3720 char ebuf[1024];
3721 const char *name = agent->name();
3722 const char *msg = "Could not find agent library ";
3723
3724 // First check to see if agent is statically linked into executable
3725 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3726 library = agent->os_lib();
3727 } else if (agent->is_absolute_path()) {
3728 library = os::dll_load(name, ebuf, sizeof ebuf);
3729 if (library == NULL) {
3730 const char *sub_msg = " in absolute path, with error: ";
3731 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3732 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3733 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3734 // If we can't find the agent, exit.
3735 vm_exit_during_initialization(buf, NULL);
3736 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3737 }
3738 } else {
3739 // Try to load the agent from the standard dll directory
3740 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3741 name)) {
3742 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3743 }
3744 if (library == NULL) { // Try the local directory
3745 char ns[1] = {0};
3746 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3747 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3748 }
3749 if (library == NULL) {
3750 const char *sub_msg = " on the library path, with error: ";
3751 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3752 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3753 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3754 // If we can't find the agent, exit.
3755 vm_exit_during_initialization(buf, NULL);
3756 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3757 }
3758 }
3759 }
3760 agent->set_os_lib(library);
3761 agent->set_valid();
3762 }
3763
3764 // Find the OnLoad function.
3765 on_load_entry =
3766 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3767 false,
3768 on_load_symbols,
3769 num_symbol_entries));
3770 return on_load_entry;
3771 }
3772
3773 // Find the JVM_OnLoad entry point
3774 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3775 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3776 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3777 }
3778
3779 // Find the Agent_OnLoad entry point
3780 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3781 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3782 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3783 }
3784
3785 // For backwards compatibility with -Xrun
3786 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3787 // treated like -agentpath:
3788 // Must be called before agent libraries are created
3789 void Threads::convert_vm_init_libraries_to_agents() {
3790 AgentLibrary* agent;
3791 AgentLibrary* next;
3792
3793 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3794 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3795 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3796
3797 // If there is an JVM_OnLoad function it will get called later,
3798 // otherwise see if there is an Agent_OnLoad
3799 if (on_load_entry == NULL) {
3800 on_load_entry = lookup_agent_on_load(agent);
3801 if (on_load_entry != NULL) {
3802 // switch it to the agent list -- so that Agent_OnLoad will be called,
3803 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3804 Arguments::convert_library_to_agent(agent);
3805 } else {
3806 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3807 }
3808 }
3809 }
3810 }
3811
3812 // Create agents for -agentlib: -agentpath: and converted -Xrun
3813 // Invokes Agent_OnLoad
3814 // Called very early -- before JavaThreads exist
3815 void Threads::create_vm_init_agents() {
3816 extern struct JavaVM_ main_vm;
3817 AgentLibrary* agent;
3818
3819 JvmtiExport::enter_onload_phase();
3820
3821 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3822 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3823
3824 if (on_load_entry != NULL) {
3825 // Invoke the Agent_OnLoad function
3826 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3827 if (err != JNI_OK) {
3828 vm_exit_during_initialization("agent library failed to init", agent->name());
3829 }
3830 } else {
3831 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3832 }
3833 }
3834 JvmtiExport::enter_primordial_phase();
3835 }
3836
3837 extern "C" {
3838 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3839 }
3840
3841 void Threads::shutdown_vm_agents() {
3842 // Send any Agent_OnUnload notifications
3843 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3844 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3845 extern struct JavaVM_ main_vm;
3846 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3847
3848 // Find the Agent_OnUnload function.
3849 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3850 os::find_agent_function(agent,
3851 false,
3852 on_unload_symbols,
3853 num_symbol_entries));
3854
3855 // Invoke the Agent_OnUnload function
3856 if (unload_entry != NULL) {
3857 JavaThread* thread = JavaThread::current();
3858 ThreadToNativeFromVM ttn(thread);
3859 HandleMark hm(thread);
3860 (*unload_entry)(&main_vm);
3861 }
3862 }
3863 }
3864
3865 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3866 // Invokes JVM_OnLoad
3867 void Threads::create_vm_init_libraries() {
3868 extern struct JavaVM_ main_vm;
3869 AgentLibrary* agent;
3870
3871 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3872 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3873
3874 if (on_load_entry != NULL) {
3875 // Invoke the JVM_OnLoad function
3876 JavaThread* thread = JavaThread::current();
3877 ThreadToNativeFromVM ttn(thread);
3878 HandleMark hm(thread);
3879 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3880 if (err != JNI_OK) {
3881 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3882 }
3883 } else {
3884 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3885 }
3886 }
3887 }
3888
3889 // Last thread running calls java.lang.Shutdown.shutdown()
3890 void JavaThread::invoke_shutdown_hooks() {
3891 HandleMark hm(this);
3892
3893 // We could get here with a pending exception, if so clear it now.
3894 if (this->has_pending_exception()) {
3895 this->clear_pending_exception();
3896 }
3897
3898 EXCEPTION_MARK;
3899 Klass* k =
3900 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3901 THREAD);
3902 if (k != NULL) {
3903 // SystemDictionary::resolve_or_null will return null if there was
3904 // an exception. If we cannot load the Shutdown class, just don't
3905 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3906 // and finalizers (if runFinalizersOnExit is set) won't be run.
3907 // Note that if a shutdown hook was registered or runFinalizersOnExit
3908 // was called, the Shutdown class would have already been loaded
3909 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3910 instanceKlassHandle shutdown_klass (THREAD, k);
3911 JavaValue result(T_VOID);
3912 JavaCalls::call_static(&result,
3913 shutdown_klass,
3914 vmSymbols::shutdown_method_name(),
3915 vmSymbols::void_method_signature(),
3916 THREAD);
3917 }
3918 CLEAR_PENDING_EXCEPTION;
3919 }
3920
3921 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3922 // the program falls off the end of main(). Another VM exit path is through
3923 // vm_exit() when the program calls System.exit() to return a value or when
3924 // there is a serious error in VM. The two shutdown paths are not exactly
3925 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3926 // and VM_Exit op at VM level.
3927 //
3928 // Shutdown sequence:
3929 // + Shutdown native memory tracking if it is on
3930 // + Wait until we are the last non-daemon thread to execute
3931 // <-- every thing is still working at this moment -->
3932 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3933 // shutdown hooks, run finalizers if finalization-on-exit
3934 // + Call before_exit(), prepare for VM exit
3935 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3936 // currently the only user of this mechanism is File.deleteOnExit())
3937 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3938 // post thread end and vm death events to JVMTI,
3939 // stop signal thread
3940 // + Call JavaThread::exit(), it will:
3941 // > release JNI handle blocks, remove stack guard pages
3942 // > remove this thread from Threads list
3943 // <-- no more Java code from this thread after this point -->
3944 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3945 // the compiler threads at safepoint
3946 // <-- do not use anything that could get blocked by Safepoint -->
3947 // + Disable tracing at JNI/JVM barriers
3948 // + Set _vm_exited flag for threads that are still running native code
3949 // + Delete this thread
3950 // + Call exit_globals()
3951 // > deletes tty
3952 // > deletes PerfMemory resources
3953 // + Return to caller
3954
3955 bool Threads::destroy_vm() {
3956 JavaThread* thread = JavaThread::current();
3957
3958 #ifdef ASSERT
3959 _vm_complete = false;
3960 #endif
3961 // Wait until we are the last non-daemon thread to execute
3962 { MutexLocker nu(Threads_lock);
3963 while (Threads::number_of_non_daemon_threads() > 1 )
3964 // This wait should make safepoint checks, wait without a timeout,
3965 // and wait as a suspend-equivalent condition.
3966 //
3967 // Note: If the FlatProfiler is running and this thread is waiting
3968 // for another non-daemon thread to finish, then the FlatProfiler
3969 // is waiting for the external suspend request on this thread to
3970 // complete. wait_for_ext_suspend_completion() will eventually
3971 // timeout, but that takes time. Making this wait a suspend-
3972 // equivalent condition solves that timeout problem.
3973 //
3974 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3975 Mutex::_as_suspend_equivalent_flag);
3976 }
3977
3978 // Hang forever on exit if we are reporting an error.
3979 if (ShowMessageBoxOnError && is_error_reported()) {
3980 os::infinite_sleep();
3981 }
3982 os::wait_for_keypress_at_exit();
3983
3984 if (JDK_Version::is_jdk12x_version()) {
3985 // We are the last thread running, so check if finalizers should be run.
3986 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3987 HandleMark rm(thread);
3988 Universe::run_finalizers_on_exit();
3989 } else {
3990 // run Java level shutdown hooks
3991 thread->invoke_shutdown_hooks();
3992 }
3993
3994 before_exit(thread);
3995
3996 thread->exit(true);
3997
3998 // Stop VM thread.
3999 {
4000 // 4945125 The vm thread comes to a safepoint during exit.
4001 // GC vm_operations can get caught at the safepoint, and the
4002 // heap is unparseable if they are caught. Grab the Heap_lock
4003 // to prevent this. The GC vm_operations will not be able to
4004 // queue until after the vm thread is dead.
4005 // After this point, we'll never emerge out of the safepoint before
4006 // the VM exits, so concurrent GC threads do not need to be explicitly
4007 // stopped; they remain inactive until the process exits.
4008 // Note: some concurrent G1 threads may be running during a safepoint,
4009 // but these will not be accessing the heap, just some G1-specific side
4010 // data structures that are not accessed by any other threads but them
4011 // after this point in a terminal safepoint.
4012
4013 MutexLocker ml(Heap_lock);
4014
4015 VMThread::wait_for_vm_thread_exit();
4016 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4017 VMThread::destroy();
4018 }
4019
4020 // clean up ideal graph printers
4021 #if defined(COMPILER2) && !defined(PRODUCT)
4022 IdealGraphPrinter::clean_up();
4023 #endif
4024
4025 // Now, all Java threads are gone except daemon threads. Daemon threads
4026 // running Java code or in VM are stopped by the Safepoint. However,
4027 // daemon threads executing native code are still running. But they
4028 // will be stopped at native=>Java/VM barriers. Note that we can't
4029 // simply kill or suspend them, as it is inherently deadlock-prone.
4030
4031 #ifndef PRODUCT
4032 // disable function tracing at JNI/JVM barriers
4033 TraceJNICalls = false;
4034 TraceJVMCalls = false;
4035 TraceRuntimeCalls = false;
4036 #endif
4037
4038 VM_Exit::set_vm_exited();
4039
4040 notify_vm_shutdown();
4041
4042 delete thread;
4043
4044 // exit_globals() will delete tty
4045 exit_globals();
4046
4047 return true;
4048 }
4049
4050
4051 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4052 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4053 return is_supported_jni_version(version);
4054 }
4055
4056
4057 jboolean Threads::is_supported_jni_version(jint version) {
4058 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4059 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4060 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4061 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4062 return JNI_FALSE;
4063 }
4064
4065
4066 void Threads::add(JavaThread* p, bool force_daemon) {
4067 // The threads lock must be owned at this point
4068 assert_locked_or_safepoint(Threads_lock);
4069
4070 // See the comment for this method in thread.hpp for its purpose and
4071 // why it is called here.
4072 p->initialize_queues();
4073 p->set_next(_thread_list);
4074 _thread_list = p;
4075 _number_of_threads++;
4076 oop threadObj = p->threadObj();
4077 bool daemon = true;
4078 // Bootstrapping problem: threadObj can be null for initial
4079 // JavaThread (or for threads attached via JNI)
4080 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4081 _number_of_non_daemon_threads++;
4082 daemon = false;
4083 }
4084
4085 p->set_safepoint_visible(true);
4086
4087 ThreadService::add_thread(p, daemon);
4088
4089 // Possible GC point.
4090 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4091 }
4092
4093 void Threads::remove(JavaThread* p) {
4094 // Extra scope needed for Thread_lock, so we can check
4095 // that we do not remove thread without safepoint code notice
4096 { MutexLocker ml(Threads_lock);
4097
4098 assert(includes(p), "p must be present");
4099
4100 JavaThread* current = _thread_list;
4101 JavaThread* prev = NULL;
4102
4103 while (current != p) {
4104 prev = current;
4105 current = current->next();
4106 }
4107
4108 if (prev) {
4109 prev->set_next(current->next());
4110 } else {
4111 _thread_list = p->next();
4112 }
4113 _number_of_threads--;
4114 oop threadObj = p->threadObj();
4115 bool daemon = true;
4116 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4117 _number_of_non_daemon_threads--;
4118 daemon = false;
4119
4120 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4121 // on destroy_vm will wake up.
4122 if (number_of_non_daemon_threads() == 1)
4123 Threads_lock->notify_all();
4124 }
4125 ThreadService::remove_thread(p, daemon);
4126
4127 // Make sure that safepoint code disregard this thread. This is needed since
4128 // the thread might mess around with locks after this point. This can cause it
4129 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4130 // of this thread since it is removed from the queue.
4131 p->set_terminated_value();
4132
4133 // Now, this thread is not visible to safepoint
4134 p->set_safepoint_visible(false);
4135 // once the thread becomes safepoint invisible, we can not use its per-thread
4136 // recorder. And Threads::do_threads() no longer walks this thread, so we have
4137 // to release its per-thread recorder here.
4138 MemTracker::thread_exiting(p);
4139 } // unlock Threads_lock
4140
4141 // Since Events::log uses a lock, we grab it outside the Threads_lock
4142 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4143 }
4144
4145 // Threads_lock must be held when this is called (or must be called during a safepoint)
4146 bool Threads::includes(JavaThread* p) {
4147 assert(Threads_lock->is_locked(), "sanity check");
4148 ALL_JAVA_THREADS(q) {
4149 if (q == p ) {
4150 return true;
4151 }
4152 }
4153 return false;
4154 }
4155
4156 // Operations on the Threads list for GC. These are not explicitly locked,
4157 // but the garbage collector must provide a safe context for them to run.
4158 // In particular, these things should never be called when the Threads_lock
4159 // is held by some other thread. (Note: the Safepoint abstraction also
4160 // uses the Threads_lock to gurantee this property. It also makes sure that
4161 // all threads gets blocked when exiting or starting).
4162
4163 void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4164 ALL_JAVA_THREADS(p) {
4165 p->oops_do(f, cld_f, cf);
4166 }
4167 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4168 }
4169
4170 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4171 // Introduce a mechanism allowing parallel threads to claim threads as
4172 // root groups. Overhead should be small enough to use all the time,
4173 // even in sequential code.
4174 SharedHeap* sh = SharedHeap::heap();
4175 // Cannot yet substitute active_workers for n_par_threads
4176 // because of G1CollectedHeap::verify() use of
4177 // SharedHeap::process_strong_roots(). n_par_threads == 0 will
4178 // turn off parallelism in process_strong_roots while active_workers
4179 // is being used for parallelism elsewhere.
4180 bool is_par = sh->n_par_threads() > 0;
4181 assert(!is_par ||
4182 (SharedHeap::heap()->n_par_threads() ==
4183 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4184 int cp = SharedHeap::heap()->strong_roots_parity();
4185 ALL_JAVA_THREADS(p) {
4186 if (p->claim_oops_do(is_par, cp)) {
4187 p->oops_do(f, cld_f, cf);
4188 }
4189 }
4190 VMThread* vmt = VMThread::vm_thread();
4191 if (vmt->claim_oops_do(is_par, cp)) {
4192 vmt->oops_do(f, cld_f, cf);
4193 }
4194 }
4195
4196 #if INCLUDE_ALL_GCS
4197 // Used by ParallelScavenge
4198 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4199 ALL_JAVA_THREADS(p) {
4200 q->enqueue(new ThreadRootsTask(p));
4201 }
4202 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4203 }
4204
4205 // Used by Parallel Old
4206 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4207 ALL_JAVA_THREADS(p) {
4208 q->enqueue(new ThreadRootsMarkingTask(p));
4209 }
4210 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4211 }
4212 #endif // INCLUDE_ALL_GCS
4213
4214 void Threads::nmethods_do(CodeBlobClosure* cf) {
4215 ALL_JAVA_THREADS(p) {
4216 p->nmethods_do(cf);
4217 }
4218 VMThread::vm_thread()->nmethods_do(cf);
4219 }
4220
4221 void Threads::metadata_do(void f(Metadata*)) {
4222 ALL_JAVA_THREADS(p) {
4223 p->metadata_do(f);
4224 }
4225 }
4226
4227 void Threads::gc_epilogue() {
4228 ALL_JAVA_THREADS(p) {
4229 p->gc_epilogue();
4230 }
4231 }
4232
4233 void Threads::gc_prologue() {
4234 ALL_JAVA_THREADS(p) {
4235 p->gc_prologue();
4236 }
4237 }
4238
4239 void Threads::deoptimized_wrt_marked_nmethods() {
4240 ALL_JAVA_THREADS(p) {
4241 p->deoptimized_wrt_marked_nmethods();
4242 }
4243 }
4244
4245
4246 // Get count Java threads that are waiting to enter the specified monitor.
4247 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4248 address monitor, bool doLock) {
4249 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4250 "must grab Threads_lock or be at safepoint");
4251 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4252
4253 int i = 0;
4254 {
4255 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4256 ALL_JAVA_THREADS(p) {
4257 if (p->is_Compiler_thread()) continue;
4258
4259 address pending = (address)p->current_pending_monitor();
4260 if (pending == monitor) { // found a match
4261 if (i < count) result->append(p); // save the first count matches
4262 i++;
4263 }
4264 }
4265 }
4266 return result;
4267 }
4268
4269
4270 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4271 assert(doLock ||
4272 Threads_lock->owned_by_self() ||
4273 SafepointSynchronize::is_at_safepoint(),
4274 "must grab Threads_lock or be at safepoint");
4275
4276 // NULL owner means not locked so we can skip the search
4277 if (owner == NULL) return NULL;
4278
4279 {
4280 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4281 ALL_JAVA_THREADS(p) {
4282 // first, see if owner is the address of a Java thread
4283 if (owner == (address)p) return p;
4284 }
4285 }
4286 // Cannot assert on lack of success here since this function may be
4287 // used by code that is trying to report useful problem information
4288 // like deadlock detection.
4289 if (UseHeavyMonitors) return NULL;
4290
4291 //
4292 // If we didn't find a matching Java thread and we didn't force use of
4293 // heavyweight monitors, then the owner is the stack address of the
4294 // Lock Word in the owning Java thread's stack.
4295 //
4296 JavaThread* the_owner = NULL;
4297 {
4298 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4299 ALL_JAVA_THREADS(q) {
4300 if (q->is_lock_owned(owner)) {
4301 the_owner = q;
4302 break;
4303 }
4304 }
4305 }
4306 // cannot assert on lack of success here; see above comment
4307 return the_owner;
4308 }
4309
4310 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4311 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4312 char buf[32];
4313 st->print_cr(os::local_time_string(buf, sizeof(buf)));
4314
4315 st->print_cr("Full thread dump %s (%s %s):",
4316 Abstract_VM_Version::vm_name(),
4317 Abstract_VM_Version::vm_release(),
4318 Abstract_VM_Version::vm_info_string()
4319 );
4320 st->cr();
4321
4322 #if INCLUDE_ALL_GCS
4323 // Dump concurrent locks
4324 ConcurrentLocksDump concurrent_locks;
4325 if (print_concurrent_locks) {
4326 concurrent_locks.dump_at_safepoint();
4327 }
4328 #endif // INCLUDE_ALL_GCS
4329
4330 ALL_JAVA_THREADS(p) {
4331 ResourceMark rm;
4332 p->print_on(st);
4333 if (print_stacks) {
4334 if (internal_format) {
4335 p->trace_stack();
4336 } else {
4337 p->print_stack_on(st);
4338 }
4339 }
4340 st->cr();
4341 #if INCLUDE_ALL_GCS
4342 if (print_concurrent_locks) {
4343 concurrent_locks.print_locks_on(p, st);
4344 }
4345 #endif // INCLUDE_ALL_GCS
4346 }
4347
4348 VMThread::vm_thread()->print_on(st);
4349 st->cr();
4350 Universe::heap()->print_gc_threads_on(st);
4351 WatcherThread* wt = WatcherThread::watcher_thread();
4352 if (wt != NULL) {
4353 wt->print_on(st);
4354 st->cr();
4355 }
4356 CompileBroker::print_compiler_threads_on(st);
4357 st->flush();
4358 }
4359
4360 // Threads::print_on_error() is called by fatal error handler. It's possible
4361 // that VM is not at safepoint and/or current thread is inside signal handler.
4362 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4363 // memory (even in resource area), it might deadlock the error handler.
4364 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4365 bool found_current = false;
4366 st->print_cr("Java Threads: ( => current thread )");
4367 ALL_JAVA_THREADS(thread) {
4368 bool is_current = (current == thread);
4369 found_current = found_current || is_current;
4370
4371 st->print("%s", is_current ? "=>" : " ");
4372
4373 st->print(PTR_FORMAT, thread);
4374 st->print(" ");
4375 thread->print_on_error(st, buf, buflen);
4376 st->cr();
4377 }
4378 st->cr();
4379
4380 st->print_cr("Other Threads:");
4381 if (VMThread::vm_thread()) {
4382 bool is_current = (current == VMThread::vm_thread());
4383 found_current = found_current || is_current;
4384 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4385
4386 st->print(PTR_FORMAT, VMThread::vm_thread());
4387 st->print(" ");
4388 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4389 st->cr();
4390 }
4391 WatcherThread* wt = WatcherThread::watcher_thread();
4392 if (wt != NULL) {
4393 bool is_current = (current == wt);
4394 found_current = found_current || is_current;
4395 st->print("%s", is_current ? "=>" : " ");
4396
4397 st->print(PTR_FORMAT, wt);
4398 st->print(" ");
4399 wt->print_on_error(st, buf, buflen);
4400 st->cr();
4401 }
4402 if (!found_current) {
4403 st->cr();
4404 st->print("=>" PTR_FORMAT " (exited) ", current);
4405 current->print_on_error(st, buf, buflen);
4406 st->cr();
4407 }
4408 }
4409
4410 // Internal SpinLock and Mutex
4411 // Based on ParkEvent
4412
4413 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4414 //
4415 // We employ SpinLocks _only for low-contention, fixed-length
4416 // short-duration critical sections where we're concerned
4417 // about native mutex_t or HotSpot Mutex:: latency.
4418 // The mux construct provides a spin-then-block mutual exclusion
4419 // mechanism.
4420 //
4421 // Testing has shown that contention on the ListLock guarding gFreeList
4422 // is common. If we implement ListLock as a simple SpinLock it's common
4423 // for the JVM to devolve to yielding with little progress. This is true
4424 // despite the fact that the critical sections protected by ListLock are
4425 // extremely short.
4426 //
4427 // TODO-FIXME: ListLock should be of type SpinLock.
4428 // We should make this a 1st-class type, integrated into the lock
4429 // hierarchy as leaf-locks. Critically, the SpinLock structure
4430 // should have sufficient padding to avoid false-sharing and excessive
4431 // cache-coherency traffic.
4432
4433
4434 typedef volatile int SpinLockT ;
4435
4436 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4437 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4438 return ; // normal fast-path return
4439 }
4440
4441 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4442 TEVENT (SpinAcquire - ctx) ;
4443 int ctr = 0 ;
4444 int Yields = 0 ;
4445 for (;;) {
4446 while (*adr != 0) {
4447 ++ctr ;
4448 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4449 if (Yields > 5) {
4450 // Consider using a simple NakedSleep() instead.
4451 // Then SpinAcquire could be called by non-JVM threads
4452 Thread::current()->_ParkEvent->park(1) ;
4453 } else {
4454 os::NakedYield() ;
4455 ++Yields ;
4456 }
4457 } else {
4458 SpinPause() ;
4459 }
4460 }
4461 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4462 }
4463 }
4464
4465 void Thread::SpinRelease (volatile int * adr) {
4466 assert (*adr != 0, "invariant") ;
4467 OrderAccess::fence() ; // guarantee at least release consistency.
4468 // Roach-motel semantics.
4469 // It's safe if subsequent LDs and STs float "up" into the critical section,
4470 // but prior LDs and STs within the critical section can't be allowed
4471 // to reorder or float past the ST that releases the lock.
4472 *adr = 0 ;
4473 }
4474
4475 // muxAcquire and muxRelease:
4476 //
4477 // * muxAcquire and muxRelease support a single-word lock-word construct.
4478 // The LSB of the word is set IFF the lock is held.
4479 // The remainder of the word points to the head of a singly-linked list
4480 // of threads blocked on the lock.
4481 //
4482 // * The current implementation of muxAcquire-muxRelease uses its own
4483 // dedicated Thread._MuxEvent instance. If we're interested in
4484 // minimizing the peak number of extant ParkEvent instances then
4485 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4486 // as certain invariants were satisfied. Specifically, care would need
4487 // to be taken with regards to consuming unpark() "permits".
4488 // A safe rule of thumb is that a thread would never call muxAcquire()
4489 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4490 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4491 // consume an unpark() permit intended for monitorenter, for instance.
4492 // One way around this would be to widen the restricted-range semaphore
4493 // implemented in park(). Another alternative would be to provide
4494 // multiple instances of the PlatformEvent() for each thread. One
4495 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4496 //
4497 // * Usage:
4498 // -- Only as leaf locks
4499 // -- for short-term locking only as muxAcquire does not perform
4500 // thread state transitions.
4501 //
4502 // Alternatives:
4503 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4504 // but with parking or spin-then-park instead of pure spinning.
4505 // * Use Taura-Oyama-Yonenzawa locks.
4506 // * It's possible to construct a 1-0 lock if we encode the lockword as
4507 // (List,LockByte). Acquire will CAS the full lockword while Release
4508 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4509 // acquiring threads use timers (ParkTimed) to detect and recover from
4510 // the stranding window. Thread/Node structures must be aligned on 256-byte
4511 // boundaries by using placement-new.
4512 // * Augment MCS with advisory back-link fields maintained with CAS().
4513 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4514 // The validity of the backlinks must be ratified before we trust the value.
4515 // If the backlinks are invalid the exiting thread must back-track through the
4516 // the forward links, which are always trustworthy.
4517 // * Add a successor indication. The LockWord is currently encoded as
4518 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4519 // to provide the usual futile-wakeup optimization.
4520 // See RTStt for details.
4521 // * Consider schedctl.sc_nopreempt to cover the critical section.
4522 //
4523
4524
4525 typedef volatile intptr_t MutexT ; // Mux Lock-word
4526 enum MuxBits { LOCKBIT = 1 } ;
4527
4528 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4529 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4530 if (w == 0) return ;
4531 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4532 return ;
4533 }
4534
4535 TEVENT (muxAcquire - Contention) ;
4536 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4537 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4538 for (;;) {
4539 int its = (os::is_MP() ? 100 : 0) + 1 ;
4540
4541 // Optional spin phase: spin-then-park strategy
4542 while (--its >= 0) {
4543 w = *Lock ;
4544 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4545 return ;
4546 }
4547 }
4548
4549 Self->reset() ;
4550 Self->OnList = intptr_t(Lock) ;
4551 // The following fence() isn't _strictly necessary as the subsequent
4552 // CAS() both serializes execution and ratifies the fetched *Lock value.
4553 OrderAccess::fence();
4554 for (;;) {
4555 w = *Lock ;
4556 if ((w & LOCKBIT) == 0) {
4557 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4558 Self->OnList = 0 ; // hygiene - allows stronger asserts
4559 return ;
4560 }
4561 continue ; // Interference -- *Lock changed -- Just retry
4562 }
4563 assert (w & LOCKBIT, "invariant") ;
4564 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4565 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4566 }
4567
4568 while (Self->OnList != 0) {
4569 Self->park() ;
4570 }
4571 }
4572 }
4573
4574 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4575 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4576 if (w == 0) return ;
4577 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4578 return ;
4579 }
4580
4581 TEVENT (muxAcquire - Contention) ;
4582 ParkEvent * ReleaseAfter = NULL ;
4583 if (ev == NULL) {
4584 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4585 }
4586 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4587 for (;;) {
4588 guarantee (ev->OnList == 0, "invariant") ;
4589 int its = (os::is_MP() ? 100 : 0) + 1 ;
4590
4591 // Optional spin phase: spin-then-park strategy
4592 while (--its >= 0) {
4593 w = *Lock ;
4594 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4595 if (ReleaseAfter != NULL) {
4596 ParkEvent::Release (ReleaseAfter) ;
4597 }
4598 return ;
4599 }
4600 }
4601
4602 ev->reset() ;
4603 ev->OnList = intptr_t(Lock) ;
4604 // The following fence() isn't _strictly necessary as the subsequent
4605 // CAS() both serializes execution and ratifies the fetched *Lock value.
4606 OrderAccess::fence();
4607 for (;;) {
4608 w = *Lock ;
4609 if ((w & LOCKBIT) == 0) {
4610 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4611 ev->OnList = 0 ;
4612 // We call ::Release while holding the outer lock, thus
4613 // artificially lengthening the critical section.
4614 // Consider deferring the ::Release() until the subsequent unlock(),
4615 // after we've dropped the outer lock.
4616 if (ReleaseAfter != NULL) {
4617 ParkEvent::Release (ReleaseAfter) ;
4618 }
4619 return ;
4620 }
4621 continue ; // Interference -- *Lock changed -- Just retry
4622 }
4623 assert (w & LOCKBIT, "invariant") ;
4624 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4625 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4626 }
4627
4628 while (ev->OnList != 0) {
4629 ev->park() ;
4630 }
4631 }
4632 }
4633
4634 // Release() must extract a successor from the list and then wake that thread.
4635 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4636 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4637 // Release() would :
4638 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4639 // (B) Extract a successor from the private list "in-hand"
4640 // (C) attempt to CAS() the residual back into *Lock over null.
4641 // If there were any newly arrived threads and the CAS() would fail.
4642 // In that case Release() would detach the RATs, re-merge the list in-hand
4643 // with the RATs and repeat as needed. Alternately, Release() might
4644 // detach and extract a successor, but then pass the residual list to the wakee.
4645 // The wakee would be responsible for reattaching and remerging before it
4646 // competed for the lock.
4647 //
4648 // Both "pop" and DMR are immune from ABA corruption -- there can be
4649 // multiple concurrent pushers, but only one popper or detacher.
4650 // This implementation pops from the head of the list. This is unfair,
4651 // but tends to provide excellent throughput as hot threads remain hot.
4652 // (We wake recently run threads first).
4653
4654 void Thread::muxRelease (volatile intptr_t * Lock) {
4655 for (;;) {
4656 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4657 assert (w & LOCKBIT, "invariant") ;
4658 if (w == LOCKBIT) return ;
4659 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4660 assert (List != NULL, "invariant") ;
4661 assert (List->OnList == intptr_t(Lock), "invariant") ;
4662 ParkEvent * nxt = List->ListNext ;
4663
4664 // The following CAS() releases the lock and pops the head element.
4665 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4666 continue ;
4667 }
4668 List->OnList = 0 ;
4669 OrderAccess::fence() ;
4670 List->unpark () ;
4671 return ;
4672 }
4673 }
4674
4675
4676 void Threads::verify() {
4677 ALL_JAVA_THREADS(p) {
4678 p->verify();
4679 }
4680 VMThread* thread = VMThread::vm_thread();
4681 if (thread != NULL) thread->verify();
4682 }