1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "jvmtifiles/jvmtiEnv.hpp"
36 #include "memory/gcLocker.inline.hpp"
37 #include "memory/metaspaceShared.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "memory/universe.inline.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/objArrayOop.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/symbol.hpp"
44 #include "prims/jvm_misc.hpp"
45 #include "prims/jvmtiExport.hpp"
46 #include "prims/jvmtiThreadState.hpp"
47 #include "prims/privilegedStack.hpp"
48 #include "runtime/arguments.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/deoptimization.hpp"
51 #include "runtime/fprofiler.hpp"
52 #include "runtime/frame.inline.hpp"
53 #include "runtime/init.hpp"
54 #include "runtime/interfaceSupport.hpp"
55 #include "runtime/java.hpp"
56 #include "runtime/javaCalls.hpp"
57 #include "runtime/jniPeriodicChecker.hpp"
58 #include "runtime/memprofiler.hpp"
59 #include "runtime/mutexLocker.hpp"
60 #include "runtime/objectMonitor.hpp"
61 #include "runtime/orderAccess.inline.hpp"
62 #include "runtime/osThread.hpp"
63 #include "runtime/safepoint.hpp"
64 #include "runtime/sharedRuntime.hpp"
65 #include "runtime/statSampler.hpp"
66 #include "runtime/stubRoutines.hpp"
67 #include "runtime/task.hpp"
68 #include "runtime/thread.inline.hpp"
69 #include "runtime/threadCritical.hpp"
70 #include "runtime/threadLocalStorage.hpp"
71 #include "runtime/vframe.hpp"
72 #include "runtime/vframeArray.hpp"
73 #include "runtime/vframe_hp.hpp"
74 #include "runtime/vmThread.hpp"
75 #include "runtime/vm_operations.hpp"
76 #include "services/attachListener.hpp"
77 #include "services/management.hpp"
78 #include "services/memTracker.hpp"
79 #include "services/threadService.hpp"
80 #include "trace/tracing.hpp"
81 #include "trace/traceMacros.hpp"
82 #include "utilities/defaultStream.hpp"
83 #include "utilities/dtrace.hpp"
84 #include "utilities/events.hpp"
85 #include "utilities/preserveException.hpp"
86 #include "utilities/macros.hpp"
87 #ifdef TARGET_OS_FAMILY_linux
88 # include "os_linux.inline.hpp"
89 #endif
90 #ifdef TARGET_OS_FAMILY_solaris
91 # include "os_solaris.inline.hpp"
92 #endif
93 #ifdef TARGET_OS_FAMILY_windows
94 # include "os_windows.inline.hpp"
95 #endif
96 #ifdef TARGET_OS_FAMILY_bsd
97 # include "os_bsd.inline.hpp"
98 #endif
99 #if INCLUDE_ALL_GCS
100 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
102 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
103 #endif // INCLUDE_ALL_GCS
104 #ifdef COMPILER1
105 #include "c1/c1_Compiler.hpp"
106 #endif
107 #ifdef COMPILER2
108 #include "opto/c2compiler.hpp"
109 #include "opto/idealGraphPrinter.hpp"
110 #endif
111 #if INCLUDE_RTM_OPT
112 #include "runtime/rtmLocking.hpp"
113 #endif
114
115 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
116
117 #ifdef DTRACE_ENABLED
118
119 // Only bother with this argument setup if dtrace is available
120
121 #ifndef USDT2
122 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
123 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
124 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
125 intptr_t, intptr_t, bool);
126 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
127 intptr_t, intptr_t, bool);
128
129 #define DTRACE_THREAD_PROBE(probe, javathread) \
130 { \
131 ResourceMark rm(this); \
132 int len = 0; \
133 const char* name = (javathread)->get_thread_name(); \
134 len = strlen(name); \
135 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
136 name, len, \
137 java_lang_Thread::thread_id((javathread)->threadObj()), \
138 (javathread)->osthread()->thread_id(), \
139 java_lang_Thread::is_daemon((javathread)->threadObj())); \
140 }
141
142 #else /* USDT2 */
143
144 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
145 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
146
147 #define DTRACE_THREAD_PROBE(probe, javathread) \
148 { \
149 ResourceMark rm(this); \
150 int len = 0; \
151 const char* name = (javathread)->get_thread_name(); \
152 len = strlen(name); \
153 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
154 (char *) name, len, \
155 java_lang_Thread::thread_id((javathread)->threadObj()), \
156 (uintptr_t) (javathread)->osthread()->thread_id(), \
157 java_lang_Thread::is_daemon((javathread)->threadObj())); \
158 }
159
160 #endif /* USDT2 */
161
162 #else // ndef DTRACE_ENABLED
163
164 #define DTRACE_THREAD_PROBE(probe, javathread)
165
166 #endif // ndef DTRACE_ENABLED
167
168
169 // Class hierarchy
170 // - Thread
171 // - VMThread
172 // - WatcherThread
173 // - ConcurrentMarkSweepThread
174 // - JavaThread
175 // - CompilerThread
176
177 // ======= Thread ========
178 // Support for forcing alignment of thread objects for biased locking
179 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
180 if (UseBiasedLocking) {
181 const int alignment = markOopDesc::biased_lock_alignment;
182 size_t aligned_size = size + (alignment - sizeof(intptr_t));
183 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
184 : AllocateHeap(aligned_size, flags, CURRENT_PC,
185 AllocFailStrategy::RETURN_NULL);
186 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
187 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
188 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
189 "JavaThread alignment code overflowed allocated storage");
190 if (TraceBiasedLocking) {
191 if (aligned_addr != real_malloc_addr)
192 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
193 real_malloc_addr, aligned_addr);
194 }
195 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
196 return aligned_addr;
197 } else {
198 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
199 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
200 }
201 }
202
203 void Thread::operator delete(void* p) {
204 if (UseBiasedLocking) {
205 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
206 FreeHeap(real_malloc_addr, mtThread);
207 } else {
208 FreeHeap(p, mtThread);
209 }
210 }
211
212
213 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
214 // JavaThread
215
216
217 Thread::Thread() {
218 // stack and get_thread
219 set_stack_base(NULL);
220 set_stack_size(0);
221 set_self_raw_id(0);
222 set_lgrp_id(-1);
223
224 // allocated data structures
225 set_osthread(NULL);
226 set_resource_area(new (mtThread)ResourceArea());
227 DEBUG_ONLY(_current_resource_mark = NULL;)
228 set_handle_area(new (mtThread) HandleArea(NULL));
229 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
230 set_active_handles(NULL);
231 set_free_handle_block(NULL);
232 set_last_handle_mark(NULL);
233
234 // This initial value ==> never claimed.
235 _oops_do_parity = 0;
236 // the handle mark links itself to last_handle_mark
237 new HandleMark(this);
238
239 // plain initialization
240 debug_only(_owned_locks = NULL;)
241 debug_only(_allow_allocation_count = 0;)
242 NOT_PRODUCT(_allow_safepoint_count = 0;)
243 NOT_PRODUCT(_skip_gcalot = false;)
244 _jvmti_env_iteration_count = 0;
245 set_allocated_bytes(0);
246 _vm_operation_started_count = 0;
247 _vm_operation_completed_count = 0;
248 _current_pending_monitor = NULL;
249 _current_pending_monitor_is_from_java = true;
250 _current_waiting_monitor = NULL;
251 _num_nested_signal = 0;
252 omFreeList = NULL ;
253 omFreeCount = 0 ;
254 omFreeProvision = 32 ;
255 omInUseList = NULL ;
256 omInUseCount = 0 ;
257
258 #ifdef ASSERT
259 _visited_for_critical_count = false;
260 #endif
261
262 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
263 _suspend_flags = 0;
264
265 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
266 _hashStateX = os::random() ;
267 _hashStateY = 842502087 ;
268 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
269 _hashStateW = 273326509 ;
270
271 _OnTrap = 0 ;
272 _schedctl = NULL ;
273 _Stalled = 0 ;
274 _TypeTag = 0x2BAD ;
275
276 // Many of the following fields are effectively final - immutable
277 // Note that nascent threads can't use the Native Monitor-Mutex
278 // construct until the _MutexEvent is initialized ...
279 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
280 // we might instead use a stack of ParkEvents that we could provision on-demand.
281 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
282 // and ::Release()
283 _ParkEvent = ParkEvent::Allocate (this) ;
284 _SleepEvent = ParkEvent::Allocate (this) ;
285 _MutexEvent = ParkEvent::Allocate (this) ;
286 _MuxEvent = ParkEvent::Allocate (this) ;
287
288 #ifdef CHECK_UNHANDLED_OOPS
289 if (CheckUnhandledOops) {
290 _unhandled_oops = new UnhandledOops(this);
291 }
292 #endif // CHECK_UNHANDLED_OOPS
293 #ifdef ASSERT
294 if (UseBiasedLocking) {
295 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
296 assert(this == _real_malloc_address ||
297 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
298 "bug in forced alignment of thread objects");
299 }
300 #endif /* ASSERT */
301 }
302
303 void Thread::initialize_thread_local_storage() {
304 // Note: Make sure this method only calls
305 // non-blocking operations. Otherwise, it might not work
306 // with the thread-startup/safepoint interaction.
307
308 // During Java thread startup, safepoint code should allow this
309 // method to complete because it may need to allocate memory to
310 // store information for the new thread.
311
312 // initialize structure dependent on thread local storage
313 ThreadLocalStorage::set_thread(this);
314 }
315
316 void Thread::record_stack_base_and_size() {
317 set_stack_base(os::current_stack_base());
318 set_stack_size(os::current_stack_size());
319 if (is_Java_thread()) {
320 ((JavaThread*) this)->set_stack_overflow_limit();
321 }
322 // CR 7190089: on Solaris, primordial thread's stack is adjusted
323 // in initialize_thread(). Without the adjustment, stack size is
324 // incorrect if stack is set to unlimited (ulimit -s unlimited).
325 // So far, only Solaris has real implementation of initialize_thread().
326 //
327 // set up any platform-specific state.
328 os::initialize_thread(this);
329
330 #if INCLUDE_NMT
331 // record thread's native stack, stack grows downward
332 address stack_low_addr = stack_base() - stack_size();
333 MemTracker::record_thread_stack(stack_low_addr, stack_size());
334 #endif // INCLUDE_NMT
335 }
336
337
338 Thread::~Thread() {
339 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
340 ObjectSynchronizer::omFlush (this) ;
341
342 EVENT_THREAD_DESTRUCT(this);
343
344 // stack_base can be NULL if the thread is never started or exited before
345 // record_stack_base_and_size called. Although, we would like to ensure
346 // that all started threads do call record_stack_base_and_size(), there is
347 // not proper way to enforce that.
348 #if INCLUDE_NMT
349 if (_stack_base != NULL) {
350 address low_stack_addr = stack_base() - stack_size();
351 MemTracker::release_thread_stack(low_stack_addr, stack_size());
352 #ifdef ASSERT
353 set_stack_base(NULL);
354 #endif
355 }
356 #endif // INCLUDE_NMT
357
358 // deallocate data structures
359 delete resource_area();
360 // since the handle marks are using the handle area, we have to deallocated the root
361 // handle mark before deallocating the thread's handle area,
362 assert(last_handle_mark() != NULL, "check we have an element");
363 delete last_handle_mark();
364 assert(last_handle_mark() == NULL, "check we have reached the end");
365
366 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
367 // We NULL out the fields for good hygiene.
368 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
369 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
370 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
371 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
372
373 delete handle_area();
374 delete metadata_handles();
375
376 // osthread() can be NULL, if creation of thread failed.
377 if (osthread() != NULL) os::free_thread(osthread());
378
379 delete _SR_lock;
380
381 // clear thread local storage if the Thread is deleting itself
382 if (this == Thread::current()) {
383 ThreadLocalStorage::set_thread(NULL);
384 } else {
385 // In the case where we're not the current thread, invalidate all the
386 // caches in case some code tries to get the current thread or the
387 // thread that was destroyed, and gets stale information.
388 ThreadLocalStorage::invalidate_all();
389 }
390 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
391 }
392
393 // NOTE: dummy function for assertion purpose.
394 void Thread::run() {
395 ShouldNotReachHere();
396 }
397
398 #ifdef ASSERT
399 // Private method to check for dangling thread pointer
400 void check_for_dangling_thread_pointer(Thread *thread) {
401 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
402 "possibility of dangling Thread pointer");
403 }
404 #endif
405
406
407 #ifndef PRODUCT
408 // Tracing method for basic thread operations
409 void Thread::trace(const char* msg, const Thread* const thread) {
410 if (!TraceThreadEvents) return;
411 ResourceMark rm;
412 ThreadCritical tc;
413 const char *name = "non-Java thread";
414 int prio = -1;
415 if (thread->is_Java_thread()
416 && !thread->is_Compiler_thread()) {
417 // The Threads_lock must be held to get information about
418 // this thread but may not be in some situations when
419 // tracing thread events.
420 bool release_Threads_lock = false;
421 if (!Threads_lock->owned_by_self()) {
422 Threads_lock->lock();
423 release_Threads_lock = true;
424 }
425 JavaThread* jt = (JavaThread *)thread;
426 name = (char *)jt->get_thread_name();
427 oop thread_oop = jt->threadObj();
428 if (thread_oop != NULL) {
429 prio = java_lang_Thread::priority(thread_oop);
430 }
431 if (release_Threads_lock) {
432 Threads_lock->unlock();
433 }
434 }
435 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
436 }
437 #endif
438
439
440 ThreadPriority Thread::get_priority(const Thread* const thread) {
441 trace("get priority", thread);
442 ThreadPriority priority;
443 // Can return an error!
444 (void)os::get_priority(thread, priority);
445 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
446 return priority;
447 }
448
449 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
450 trace("set priority", thread);
451 debug_only(check_for_dangling_thread_pointer(thread);)
452 // Can return an error!
453 (void)os::set_priority(thread, priority);
454 }
455
456
457 void Thread::start(Thread* thread) {
458 trace("start", thread);
459 // Start is different from resume in that its safety is guaranteed by context or
460 // being called from a Java method synchronized on the Thread object.
461 if (!DisableStartThread) {
462 if (thread->is_Java_thread()) {
463 // Initialize the thread state to RUNNABLE before starting this thread.
464 // Can not set it after the thread started because we do not know the
465 // exact thread state at that time. It could be in MONITOR_WAIT or
466 // in SLEEPING or some other state.
467 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
468 java_lang_Thread::RUNNABLE);
469 }
470 os::start_thread(thread);
471 }
472 }
473
474 // Enqueue a VM_Operation to do the job for us - sometime later
475 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
476 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
477 VMThread::execute(vm_stop);
478 }
479
480
481 //
482 // Check if an external suspend request has completed (or has been
483 // cancelled). Returns true if the thread is externally suspended and
484 // false otherwise.
485 //
486 // The bits parameter returns information about the code path through
487 // the routine. Useful for debugging:
488 //
489 // set in is_ext_suspend_completed():
490 // 0x00000001 - routine was entered
491 // 0x00000010 - routine return false at end
492 // 0x00000100 - thread exited (return false)
493 // 0x00000200 - suspend request cancelled (return false)
494 // 0x00000400 - thread suspended (return true)
495 // 0x00001000 - thread is in a suspend equivalent state (return true)
496 // 0x00002000 - thread is native and walkable (return true)
497 // 0x00004000 - thread is native_trans and walkable (needed retry)
498 //
499 // set in wait_for_ext_suspend_completion():
500 // 0x00010000 - routine was entered
501 // 0x00020000 - suspend request cancelled before loop (return false)
502 // 0x00040000 - thread suspended before loop (return true)
503 // 0x00080000 - suspend request cancelled in loop (return false)
504 // 0x00100000 - thread suspended in loop (return true)
505 // 0x00200000 - suspend not completed during retry loop (return false)
506 //
507
508 // Helper class for tracing suspend wait debug bits.
509 //
510 // 0x00000100 indicates that the target thread exited before it could
511 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
512 // 0x00080000 each indicate a cancelled suspend request so they don't
513 // count as wait failures either.
514 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
515
516 class TraceSuspendDebugBits : public StackObj {
517 private:
518 JavaThread * jt;
519 bool is_wait;
520 bool called_by_wait; // meaningful when !is_wait
521 uint32_t * bits;
522
523 public:
524 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
525 uint32_t *_bits) {
526 jt = _jt;
527 is_wait = _is_wait;
528 called_by_wait = _called_by_wait;
529 bits = _bits;
530 }
531
532 ~TraceSuspendDebugBits() {
533 if (!is_wait) {
534 #if 1
535 // By default, don't trace bits for is_ext_suspend_completed() calls.
536 // That trace is very chatty.
537 return;
538 #else
539 if (!called_by_wait) {
540 // If tracing for is_ext_suspend_completed() is enabled, then only
541 // trace calls to it from wait_for_ext_suspend_completion()
542 return;
543 }
544 #endif
545 }
546
547 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
548 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
549 MutexLocker ml(Threads_lock); // needed for get_thread_name()
550 ResourceMark rm;
551
552 tty->print_cr(
553 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
554 jt->get_thread_name(), *bits);
555
556 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
557 }
558 }
559 }
560 };
561 #undef DEBUG_FALSE_BITS
562
563
564 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
565 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
566
567 bool did_trans_retry = false; // only do thread_in_native_trans retry once
568 bool do_trans_retry; // flag to force the retry
569
570 *bits |= 0x00000001;
571
572 do {
573 do_trans_retry = false;
574
575 if (is_exiting()) {
576 // Thread is in the process of exiting. This is always checked
577 // first to reduce the risk of dereferencing a freed JavaThread.
578 *bits |= 0x00000100;
579 return false;
580 }
581
582 if (!is_external_suspend()) {
583 // Suspend request is cancelled. This is always checked before
584 // is_ext_suspended() to reduce the risk of a rogue resume
585 // confusing the thread that made the suspend request.
586 *bits |= 0x00000200;
587 return false;
588 }
589
590 if (is_ext_suspended()) {
591 // thread is suspended
592 *bits |= 0x00000400;
593 return true;
594 }
595
596 // Now that we no longer do hard suspends of threads running
597 // native code, the target thread can be changing thread state
598 // while we are in this routine:
599 //
600 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
601 //
602 // We save a copy of the thread state as observed at this moment
603 // and make our decision about suspend completeness based on the
604 // copy. This closes the race where the thread state is seen as
605 // _thread_in_native_trans in the if-thread_blocked check, but is
606 // seen as _thread_blocked in if-thread_in_native_trans check.
607 JavaThreadState save_state = thread_state();
608
609 if (save_state == _thread_blocked && is_suspend_equivalent()) {
610 // If the thread's state is _thread_blocked and this blocking
611 // condition is known to be equivalent to a suspend, then we can
612 // consider the thread to be externally suspended. This means that
613 // the code that sets _thread_blocked has been modified to do
614 // self-suspension if the blocking condition releases. We also
615 // used to check for CONDVAR_WAIT here, but that is now covered by
616 // the _thread_blocked with self-suspension check.
617 //
618 // Return true since we wouldn't be here unless there was still an
619 // external suspend request.
620 *bits |= 0x00001000;
621 return true;
622 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
623 // Threads running native code will self-suspend on native==>VM/Java
624 // transitions. If its stack is walkable (should always be the case
625 // unless this function is called before the actual java_suspend()
626 // call), then the wait is done.
627 *bits |= 0x00002000;
628 return true;
629 } else if (!called_by_wait && !did_trans_retry &&
630 save_state == _thread_in_native_trans &&
631 frame_anchor()->walkable()) {
632 // The thread is transitioning from thread_in_native to another
633 // thread state. check_safepoint_and_suspend_for_native_trans()
634 // will force the thread to self-suspend. If it hasn't gotten
635 // there yet we may have caught the thread in-between the native
636 // code check above and the self-suspend. Lucky us. If we were
637 // called by wait_for_ext_suspend_completion(), then it
638 // will be doing the retries so we don't have to.
639 //
640 // Since we use the saved thread state in the if-statement above,
641 // there is a chance that the thread has already transitioned to
642 // _thread_blocked by the time we get here. In that case, we will
643 // make a single unnecessary pass through the logic below. This
644 // doesn't hurt anything since we still do the trans retry.
645
646 *bits |= 0x00004000;
647
648 // Once the thread leaves thread_in_native_trans for another
649 // thread state, we break out of this retry loop. We shouldn't
650 // need this flag to prevent us from getting back here, but
651 // sometimes paranoia is good.
652 did_trans_retry = true;
653
654 // We wait for the thread to transition to a more usable state.
655 for (int i = 1; i <= SuspendRetryCount; i++) {
656 // We used to do an "os::yield_all(i)" call here with the intention
657 // that yielding would increase on each retry. However, the parameter
658 // is ignored on Linux which means the yield didn't scale up. Waiting
659 // on the SR_lock below provides a much more predictable scale up for
660 // the delay. It also provides a simple/direct point to check for any
661 // safepoint requests from the VMThread
662
663 // temporarily drops SR_lock while doing wait with safepoint check
664 // (if we're a JavaThread - the WatcherThread can also call this)
665 // and increase delay with each retry
666 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
667
668 // check the actual thread state instead of what we saved above
669 if (thread_state() != _thread_in_native_trans) {
670 // the thread has transitioned to another thread state so
671 // try all the checks (except this one) one more time.
672 do_trans_retry = true;
673 break;
674 }
675 } // end retry loop
676
677
678 }
679 } while (do_trans_retry);
680
681 *bits |= 0x00000010;
682 return false;
683 }
684
685 //
686 // Wait for an external suspend request to complete (or be cancelled).
687 // Returns true if the thread is externally suspended and false otherwise.
688 //
689 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
690 uint32_t *bits) {
691 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
692 false /* !called_by_wait */, bits);
693
694 // local flag copies to minimize SR_lock hold time
695 bool is_suspended;
696 bool pending;
697 uint32_t reset_bits;
698
699 // set a marker so is_ext_suspend_completed() knows we are the caller
700 *bits |= 0x00010000;
701
702 // We use reset_bits to reinitialize the bits value at the top of
703 // each retry loop. This allows the caller to make use of any
704 // unused bits for their own marking purposes.
705 reset_bits = *bits;
706
707 {
708 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
709 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
710 delay, bits);
711 pending = is_external_suspend();
712 }
713 // must release SR_lock to allow suspension to complete
714
715 if (!pending) {
716 // A cancelled suspend request is the only false return from
717 // is_ext_suspend_completed() that keeps us from entering the
718 // retry loop.
719 *bits |= 0x00020000;
720 return false;
721 }
722
723 if (is_suspended) {
724 *bits |= 0x00040000;
725 return true;
726 }
727
728 for (int i = 1; i <= retries; i++) {
729 *bits = reset_bits; // reinit to only track last retry
730
731 // We used to do an "os::yield_all(i)" call here with the intention
732 // that yielding would increase on each retry. However, the parameter
733 // is ignored on Linux which means the yield didn't scale up. Waiting
734 // on the SR_lock below provides a much more predictable scale up for
735 // the delay. It also provides a simple/direct point to check for any
736 // safepoint requests from the VMThread
737
738 {
739 MutexLocker ml(SR_lock());
740 // wait with safepoint check (if we're a JavaThread - the WatcherThread
741 // can also call this) and increase delay with each retry
742 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
743
744 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
745 delay, bits);
746
747 // It is possible for the external suspend request to be cancelled
748 // (by a resume) before the actual suspend operation is completed.
749 // Refresh our local copy to see if we still need to wait.
750 pending = is_external_suspend();
751 }
752
753 if (!pending) {
754 // A cancelled suspend request is the only false return from
755 // is_ext_suspend_completed() that keeps us from staying in the
756 // retry loop.
757 *bits |= 0x00080000;
758 return false;
759 }
760
761 if (is_suspended) {
762 *bits |= 0x00100000;
763 return true;
764 }
765 } // end retry loop
766
767 // thread did not suspend after all our retries
768 *bits |= 0x00200000;
769 return false;
770 }
771
772 #ifndef PRODUCT
773 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
774
775 // This should not need to be atomic as the only way for simultaneous
776 // updates is via interrupts. Even then this should be rare or non-existant
777 // and we don't care that much anyway.
778
779 int index = _jmp_ring_index;
780 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
781 _jmp_ring[index]._target = (intptr_t) target;
782 _jmp_ring[index]._instruction = (intptr_t) instr;
783 _jmp_ring[index]._file = file;
784 _jmp_ring[index]._line = line;
785 }
786 #endif /* PRODUCT */
787
788 // Called by flat profiler
789 // Callers have already called wait_for_ext_suspend_completion
790 // The assertion for that is currently too complex to put here:
791 bool JavaThread::profile_last_Java_frame(frame* _fr) {
792 bool gotframe = false;
793 // self suspension saves needed state.
794 if (has_last_Java_frame() && _anchor.walkable()) {
795 *_fr = pd_last_frame();
796 gotframe = true;
797 }
798 return gotframe;
799 }
800
801 void Thread::interrupt(Thread* thread) {
802 trace("interrupt", thread);
803 debug_only(check_for_dangling_thread_pointer(thread);)
804 os::interrupt(thread);
805 }
806
807 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
808 trace("is_interrupted", thread);
809 debug_only(check_for_dangling_thread_pointer(thread);)
810 // Note: If clear_interrupted==false, this simply fetches and
811 // returns the value of the field osthread()->interrupted().
812 return os::is_interrupted(thread, clear_interrupted);
813 }
814
815
816 // GC Support
817 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
818 jint thread_parity = _oops_do_parity;
819 if (thread_parity != strong_roots_parity) {
820 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
821 if (res == thread_parity) {
822 return true;
823 } else {
824 guarantee(res == strong_roots_parity, "Or else what?");
825 assert(SharedHeap::heap()->workers()->active_workers() > 0,
826 "Should only fail when parallel.");
827 return false;
828 }
829 }
830 assert(SharedHeap::heap()->workers()->active_workers() > 0,
831 "Should only fail when parallel.");
832 return false;
833 }
834
835 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
836 active_handles()->oops_do(f);
837 // Do oop for ThreadShadow
838 f->do_oop((oop*)&_pending_exception);
839 handle_area()->oops_do(f);
840 }
841
842 void Thread::nmethods_do(CodeBlobClosure* cf) {
843 // no nmethods in a generic thread...
844 }
845
846 void Thread::metadata_do(void f(Metadata*)) {
847 if (metadata_handles() != NULL) {
848 for (int i = 0; i< metadata_handles()->length(); i++) {
849 f(metadata_handles()->at(i));
850 }
851 }
852 }
853
854 void Thread::print_on(outputStream* st) const {
855 // get_priority assumes osthread initialized
856 if (osthread() != NULL) {
857 int os_prio;
858 if (os::get_native_priority(this, &os_prio) == OS_OK) {
859 st->print("os_prio=%d ", os_prio);
860 }
861 st->print("tid=" INTPTR_FORMAT " ", this);
862 ext().print_on(st);
863 osthread()->print_on(st);
864 }
865 debug_only(if (WizardMode) print_owned_locks_on(st);)
866 }
867
868 // Thread::print_on_error() is called by fatal error handler. Don't use
869 // any lock or allocate memory.
870 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
871 if (is_VM_thread()) st->print("VMThread");
872 else if (is_Compiler_thread()) st->print("CompilerThread");
873 else if (is_Java_thread()) st->print("JavaThread");
874 else if (is_GC_task_thread()) st->print("GCTaskThread");
875 else if (is_Watcher_thread()) st->print("WatcherThread");
876 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
877 else st->print("Thread");
878
879 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
880 _stack_base - _stack_size, _stack_base);
881
882 if (osthread()) {
883 st->print(" [id=%d]", osthread()->thread_id());
884 }
885 }
886
887 #ifdef ASSERT
888 void Thread::print_owned_locks_on(outputStream* st) const {
889 Monitor *cur = _owned_locks;
890 if (cur == NULL) {
891 st->print(" (no locks) ");
892 } else {
893 st->print_cr(" Locks owned:");
894 while(cur) {
895 cur->print_on(st);
896 cur = cur->next();
897 }
898 }
899 }
900
901 static int ref_use_count = 0;
902
903 bool Thread::owns_locks_but_compiled_lock() const {
904 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
905 if (cur != Compile_lock) return true;
906 }
907 return false;
908 }
909
910
911 #endif
912
913 #ifndef PRODUCT
914
915 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
916 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
917 // no threads which allow_vm_block's are held
918 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
919 // Check if current thread is allowed to block at a safepoint
920 if (!(_allow_safepoint_count == 0))
921 fatal("Possible safepoint reached by thread that does not allow it");
922 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
923 fatal("LEAF method calling lock?");
924 }
925
926 #ifdef ASSERT
927 if (potential_vm_operation && is_Java_thread()
928 && !Universe::is_bootstrapping()) {
929 // Make sure we do not hold any locks that the VM thread also uses.
930 // This could potentially lead to deadlocks
931 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
932 // Threads_lock is special, since the safepoint synchronization will not start before this is
933 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
934 // since it is used to transfer control between JavaThreads and the VMThread
935 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
936 if ( (cur->allow_vm_block() &&
937 cur != Threads_lock &&
938 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
939 cur != VMOperationRequest_lock &&
940 cur != VMOperationQueue_lock) ||
941 cur->rank() == Mutex::special) {
942 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
943 }
944 }
945 }
946
947 if (GCALotAtAllSafepoints) {
948 // We could enter a safepoint here and thus have a gc
949 InterfaceSupport::check_gc_alot();
950 }
951 #endif
952 }
953 #endif
954
955 bool Thread::is_in_stack(address adr) const {
956 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
957 address end = os::current_stack_pointer();
958 // Allow non Java threads to call this without stack_base
959 if (_stack_base == NULL) return true;
960 if (stack_base() >= adr && adr >= end) return true;
961
962 return false;
963 }
964
965
966 bool Thread::is_in_usable_stack(address adr) const {
967 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
968 size_t usable_stack_size = _stack_size - stack_guard_size;
969
970 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
971 }
972
973
974 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
975 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
976 // used for compilation in the future. If that change is made, the need for these methods
977 // should be revisited, and they should be removed if possible.
978
979 bool Thread::is_lock_owned(address adr) const {
980 return on_local_stack(adr);
981 }
982
983 bool Thread::set_as_starting_thread() {
984 // NOTE: this must be called inside the main thread.
985 return os::create_main_thread((JavaThread*)this);
986 }
987
988 static void initialize_class(Symbol* class_name, TRAPS) {
989 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
990 InstanceKlass::cast(klass)->initialize(CHECK);
991 }
992
993
994 // Creates the initial ThreadGroup
995 static Handle create_initial_thread_group(TRAPS) {
996 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
997 instanceKlassHandle klass (THREAD, k);
998
999 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1000 {
1001 JavaValue result(T_VOID);
1002 JavaCalls::call_special(&result,
1003 system_instance,
1004 klass,
1005 vmSymbols::object_initializer_name(),
1006 vmSymbols::void_method_signature(),
1007 CHECK_NH);
1008 }
1009 Universe::set_system_thread_group(system_instance());
1010
1011 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1012 {
1013 JavaValue result(T_VOID);
1014 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1015 JavaCalls::call_special(&result,
1016 main_instance,
1017 klass,
1018 vmSymbols::object_initializer_name(),
1019 vmSymbols::threadgroup_string_void_signature(),
1020 system_instance,
1021 string,
1022 CHECK_NH);
1023 }
1024 return main_instance;
1025 }
1026
1027 // Creates the initial Thread
1028 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1029 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1030 instanceKlassHandle klass (THREAD, k);
1031 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1032
1033 java_lang_Thread::set_thread(thread_oop(), thread);
1034 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1035 thread->set_threadObj(thread_oop());
1036
1037 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1038
1039 JavaValue result(T_VOID);
1040 JavaCalls::call_special(&result, thread_oop,
1041 klass,
1042 vmSymbols::object_initializer_name(),
1043 vmSymbols::threadgroup_string_void_signature(),
1044 thread_group,
1045 string,
1046 CHECK_NULL);
1047 return thread_oop();
1048 }
1049
1050 static void call_initializeSystemClass(TRAPS) {
1051 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1052 instanceKlassHandle klass (THREAD, k);
1053
1054 JavaValue result(T_VOID);
1055 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1056 vmSymbols::void_method_signature(), CHECK);
1057 }
1058
1059 char java_runtime_name[128] = "";
1060 char java_runtime_version[128] = "";
1061
1062 // extract the JRE name from sun.misc.Version.java_runtime_name
1063 static const char* get_java_runtime_name(TRAPS) {
1064 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1065 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1066 fieldDescriptor fd;
1067 bool found = k != NULL &&
1068 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1069 vmSymbols::string_signature(), &fd);
1070 if (found) {
1071 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1072 if (name_oop == NULL)
1073 return NULL;
1074 const char* name = java_lang_String::as_utf8_string(name_oop,
1075 java_runtime_name,
1076 sizeof(java_runtime_name));
1077 return name;
1078 } else {
1079 return NULL;
1080 }
1081 }
1082
1083 // extract the JRE version from sun.misc.Version.java_runtime_version
1084 static const char* get_java_runtime_version(TRAPS) {
1085 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1086 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1087 fieldDescriptor fd;
1088 bool found = k != NULL &&
1089 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1090 vmSymbols::string_signature(), &fd);
1091 if (found) {
1092 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1093 if (name_oop == NULL)
1094 return NULL;
1095 const char* name = java_lang_String::as_utf8_string(name_oop,
1096 java_runtime_version,
1097 sizeof(java_runtime_version));
1098 return name;
1099 } else {
1100 return NULL;
1101 }
1102 }
1103
1104 // General purpose hook into Java code, run once when the VM is initialized.
1105 // The Java library method itself may be changed independently from the VM.
1106 static void call_postVMInitHook(TRAPS) {
1107 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1108 instanceKlassHandle klass (THREAD, k);
1109 if (klass.not_null()) {
1110 JavaValue result(T_VOID);
1111 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1112 vmSymbols::void_method_signature(),
1113 CHECK);
1114 }
1115 }
1116
1117 static void reset_vm_info_property(TRAPS) {
1118 // the vm info string
1119 ResourceMark rm(THREAD);
1120 const char *vm_info = VM_Version::vm_info_string();
1121
1122 // java.lang.System class
1123 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1124 instanceKlassHandle klass (THREAD, k);
1125
1126 // setProperty arguments
1127 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1128 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1129
1130 // return value
1131 JavaValue r(T_OBJECT);
1132
1133 // public static String setProperty(String key, String value);
1134 JavaCalls::call_static(&r,
1135 klass,
1136 vmSymbols::setProperty_name(),
1137 vmSymbols::string_string_string_signature(),
1138 key_str,
1139 value_str,
1140 CHECK);
1141 }
1142
1143
1144 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1145 assert(thread_group.not_null(), "thread group should be specified");
1146 assert(threadObj() == NULL, "should only create Java thread object once");
1147
1148 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1149 instanceKlassHandle klass (THREAD, k);
1150 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1151
1152 java_lang_Thread::set_thread(thread_oop(), this);
1153 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1154 set_threadObj(thread_oop());
1155
1156 JavaValue result(T_VOID);
1157 if (thread_name != NULL) {
1158 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1159 // Thread gets assigned specified name and null target
1160 JavaCalls::call_special(&result,
1161 thread_oop,
1162 klass,
1163 vmSymbols::object_initializer_name(),
1164 vmSymbols::threadgroup_string_void_signature(),
1165 thread_group, // Argument 1
1166 name, // Argument 2
1167 THREAD);
1168 } else {
1169 // Thread gets assigned name "Thread-nnn" and null target
1170 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1171 JavaCalls::call_special(&result,
1172 thread_oop,
1173 klass,
1174 vmSymbols::object_initializer_name(),
1175 vmSymbols::threadgroup_runnable_void_signature(),
1176 thread_group, // Argument 1
1177 Handle(), // Argument 2
1178 THREAD);
1179 }
1180
1181
1182 if (daemon) {
1183 java_lang_Thread::set_daemon(thread_oop());
1184 }
1185
1186 if (HAS_PENDING_EXCEPTION) {
1187 return;
1188 }
1189
1190 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1191 Handle threadObj(this, this->threadObj());
1192
1193 JavaCalls::call_special(&result,
1194 thread_group,
1195 group,
1196 vmSymbols::add_method_name(),
1197 vmSymbols::thread_void_signature(),
1198 threadObj, // Arg 1
1199 THREAD);
1200
1201
1202 }
1203
1204 // NamedThread -- non-JavaThread subclasses with multiple
1205 // uniquely named instances should derive from this.
1206 NamedThread::NamedThread() : Thread() {
1207 _name = NULL;
1208 _processed_thread = NULL;
1209 }
1210
1211 NamedThread::~NamedThread() {
1212 if (_name != NULL) {
1213 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1214 _name = NULL;
1215 }
1216 }
1217
1218 void NamedThread::set_name(const char* format, ...) {
1219 guarantee(_name == NULL, "Only get to set name once.");
1220 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1221 guarantee(_name != NULL, "alloc failure");
1222 va_list ap;
1223 va_start(ap, format);
1224 jio_vsnprintf(_name, max_name_len, format, ap);
1225 va_end(ap);
1226 }
1227
1228 // ======= WatcherThread ========
1229
1230 // The watcher thread exists to simulate timer interrupts. It should
1231 // be replaced by an abstraction over whatever native support for
1232 // timer interrupts exists on the platform.
1233
1234 WatcherThread* WatcherThread::_watcher_thread = NULL;
1235 bool WatcherThread::_startable = false;
1236 volatile bool WatcherThread::_should_terminate = false;
1237
1238 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1239 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1240 if (os::create_thread(this, os::watcher_thread)) {
1241 _watcher_thread = this;
1242
1243 // Set the watcher thread to the highest OS priority which should not be
1244 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1245 // is created. The only normal thread using this priority is the reference
1246 // handler thread, which runs for very short intervals only.
1247 // If the VMThread's priority is not lower than the WatcherThread profiling
1248 // will be inaccurate.
1249 os::set_priority(this, MaxPriority);
1250 if (!DisableStartThread) {
1251 os::start_thread(this);
1252 }
1253 }
1254 }
1255
1256 int WatcherThread::sleep() const {
1257 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1258
1259 // remaining will be zero if there are no tasks,
1260 // causing the WatcherThread to sleep until a task is
1261 // enrolled
1262 int remaining = PeriodicTask::time_to_wait();
1263 int time_slept = 0;
1264
1265 // we expect this to timeout - we only ever get unparked when
1266 // we should terminate or when a new task has been enrolled
1267 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1268
1269 jlong time_before_loop = os::javaTimeNanos();
1270
1271 for (;;) {
1272 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1273 jlong now = os::javaTimeNanos();
1274
1275 if (remaining == 0) {
1276 // if we didn't have any tasks we could have waited for a long time
1277 // consider the time_slept zero and reset time_before_loop
1278 time_slept = 0;
1279 time_before_loop = now;
1280 } else {
1281 // need to recalulate since we might have new tasks in _tasks
1282 time_slept = (int) ((now - time_before_loop) / 1000000);
1283 }
1284
1285 // Change to task list or spurious wakeup of some kind
1286 if (timedout || _should_terminate) {
1287 break;
1288 }
1289
1290 remaining = PeriodicTask::time_to_wait();
1291 if (remaining == 0) {
1292 // Last task was just disenrolled so loop around and wait until
1293 // another task gets enrolled
1294 continue;
1295 }
1296
1297 remaining -= time_slept;
1298 if (remaining <= 0)
1299 break;
1300 }
1301
1302 return time_slept;
1303 }
1304
1305 void WatcherThread::run() {
1306 assert(this == watcher_thread(), "just checking");
1307
1308 this->record_stack_base_and_size();
1309 this->initialize_thread_local_storage();
1310 this->set_active_handles(JNIHandleBlock::allocate_block());
1311 while(!_should_terminate) {
1312 assert(watcher_thread() == Thread::current(), "thread consistency check");
1313 assert(watcher_thread() == this, "thread consistency check");
1314
1315 // Calculate how long it'll be until the next PeriodicTask work
1316 // should be done, and sleep that amount of time.
1317 int time_waited = sleep();
1318
1319 if (is_error_reported()) {
1320 // A fatal error has happened, the error handler(VMError::report_and_die)
1321 // should abort JVM after creating an error log file. However in some
1322 // rare cases, the error handler itself might deadlock. Here we try to
1323 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1324 //
1325 // This code is in WatcherThread because WatcherThread wakes up
1326 // periodically so the fatal error handler doesn't need to do anything;
1327 // also because the WatcherThread is less likely to crash than other
1328 // threads.
1329
1330 for (;;) {
1331 if (!ShowMessageBoxOnError
1332 && (OnError == NULL || OnError[0] == '\0')
1333 && Arguments::abort_hook() == NULL) {
1334 os::sleep(this, 2 * 60 * 1000, false);
1335 fdStream err(defaultStream::output_fd());
1336 err.print_raw_cr("# [ timer expired, abort... ]");
1337 // skip atexit/vm_exit/vm_abort hooks
1338 os::die();
1339 }
1340
1341 // Wake up 5 seconds later, the fatal handler may reset OnError or
1342 // ShowMessageBoxOnError when it is ready to abort.
1343 os::sleep(this, 5 * 1000, false);
1344 }
1345 }
1346
1347 PeriodicTask::real_time_tick(time_waited);
1348 }
1349
1350 // Signal that it is terminated
1351 {
1352 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1353 _watcher_thread = NULL;
1354 Terminator_lock->notify();
1355 }
1356
1357 // Thread destructor usually does this..
1358 ThreadLocalStorage::set_thread(NULL);
1359 }
1360
1361 void WatcherThread::start() {
1362 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1363
1364 if (watcher_thread() == NULL && _startable) {
1365 _should_terminate = false;
1366 // Create the single instance of WatcherThread
1367 new WatcherThread();
1368 }
1369 }
1370
1371 void WatcherThread::make_startable() {
1372 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1373 _startable = true;
1374 }
1375
1376 void WatcherThread::stop() {
1377 {
1378 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1379 _should_terminate = true;
1380 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1381
1382 WatcherThread* watcher = watcher_thread();
1383 if (watcher != NULL)
1384 watcher->unpark();
1385 }
1386
1387 // it is ok to take late safepoints here, if needed
1388 MutexLocker mu(Terminator_lock);
1389
1390 while(watcher_thread() != NULL) {
1391 // This wait should make safepoint checks, wait without a timeout,
1392 // and wait as a suspend-equivalent condition.
1393 //
1394 // Note: If the FlatProfiler is running, then this thread is waiting
1395 // for the WatcherThread to terminate and the WatcherThread, via the
1396 // FlatProfiler task, is waiting for the external suspend request on
1397 // this thread to complete. wait_for_ext_suspend_completion() will
1398 // eventually timeout, but that takes time. Making this wait a
1399 // suspend-equivalent condition solves that timeout problem.
1400 //
1401 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1402 Mutex::_as_suspend_equivalent_flag);
1403 }
1404 }
1405
1406 void WatcherThread::unpark() {
1407 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1408 PeriodicTask_lock->notify();
1409 }
1410
1411 void WatcherThread::print_on(outputStream* st) const {
1412 st->print("\"%s\" ", name());
1413 Thread::print_on(st);
1414 st->cr();
1415 }
1416
1417 // ======= JavaThread ========
1418
1419 // A JavaThread is a normal Java thread
1420
1421 void JavaThread::initialize() {
1422 // Initialize fields
1423
1424 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1425 set_claimed_par_id(UINT_MAX);
1426
1427 set_saved_exception_pc(NULL);
1428 set_threadObj(NULL);
1429 _anchor.clear();
1430 set_entry_point(NULL);
1431 set_jni_functions(jni_functions());
1432 set_callee_target(NULL);
1433 set_vm_result(NULL);
1434 set_vm_result_2(NULL);
1435 set_vframe_array_head(NULL);
1436 set_vframe_array_last(NULL);
1437 set_deferred_locals(NULL);
1438 set_deopt_mark(NULL);
1439 set_deopt_nmethod(NULL);
1440 clear_must_deopt_id();
1441 set_monitor_chunks(NULL);
1442 set_next(NULL);
1443 set_thread_state(_thread_new);
1444 _terminated = _not_terminated;
1445 _privileged_stack_top = NULL;
1446 _array_for_gc = NULL;
1447 _suspend_equivalent = false;
1448 _in_deopt_handler = 0;
1449 _doing_unsafe_access = false;
1450 _stack_guard_state = stack_guard_unused;
1451 (void)const_cast<oop&>(_exception_oop = NULL);
1452 _exception_pc = 0;
1453 _exception_handler_pc = 0;
1454 _is_method_handle_return = 0;
1455 _jvmti_thread_state= NULL;
1456 _should_post_on_exceptions_flag = JNI_FALSE;
1457 _jvmti_get_loaded_classes_closure = NULL;
1458 _interp_only_mode = 0;
1459 _special_runtime_exit_condition = _no_async_condition;
1460 _pending_async_exception = NULL;
1461 _thread_stat = NULL;
1462 _thread_stat = new ThreadStatistics();
1463 _blocked_on_compilation = false;
1464 _jni_active_critical = 0;
1465 _do_not_unlock_if_synchronized = false;
1466 _cached_monitor_info = NULL;
1467 _parker = Parker::Allocate(this) ;
1468
1469 #ifndef PRODUCT
1470 _jmp_ring_index = 0;
1471 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1472 record_jump(NULL, NULL, NULL, 0);
1473 }
1474 #endif /* PRODUCT */
1475
1476 set_thread_profiler(NULL);
1477 if (FlatProfiler::is_active()) {
1478 // This is where we would decide to either give each thread it's own profiler
1479 // or use one global one from FlatProfiler,
1480 // or up to some count of the number of profiled threads, etc.
1481 ThreadProfiler* pp = new ThreadProfiler();
1482 pp->engage();
1483 set_thread_profiler(pp);
1484 }
1485
1486 // Setup safepoint state info for this thread
1487 ThreadSafepointState::create(this);
1488
1489 debug_only(_java_call_counter = 0);
1490
1491 // JVMTI PopFrame support
1492 _popframe_condition = popframe_inactive;
1493 _popframe_preserved_args = NULL;
1494 _popframe_preserved_args_size = 0;
1495
1496 pd_initialize();
1497 }
1498
1499 #if INCLUDE_ALL_GCS
1500 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1501 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1502 #endif // INCLUDE_ALL_GCS
1503
1504 JavaThread::JavaThread(bool is_attaching_via_jni) :
1505 Thread()
1506 #if INCLUDE_ALL_GCS
1507 , _satb_mark_queue(&_satb_mark_queue_set),
1508 _dirty_card_queue(&_dirty_card_queue_set)
1509 #endif // INCLUDE_ALL_GCS
1510 {
1511 initialize();
1512 if (is_attaching_via_jni) {
1513 _jni_attach_state = _attaching_via_jni;
1514 } else {
1515 _jni_attach_state = _not_attaching_via_jni;
1516 }
1517 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1518 }
1519
1520 bool JavaThread::reguard_stack(address cur_sp) {
1521 if (_stack_guard_state != stack_guard_yellow_disabled) {
1522 return true; // Stack already guarded or guard pages not needed.
1523 }
1524
1525 if (register_stack_overflow()) {
1526 // For those architectures which have separate register and
1527 // memory stacks, we must check the register stack to see if
1528 // it has overflowed.
1529 return false;
1530 }
1531
1532 // Java code never executes within the yellow zone: the latter is only
1533 // there to provoke an exception during stack banging. If java code
1534 // is executing there, either StackShadowPages should be larger, or
1535 // some exception code in c1, c2 or the interpreter isn't unwinding
1536 // when it should.
1537 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1538
1539 enable_stack_yellow_zone();
1540 return true;
1541 }
1542
1543 bool JavaThread::reguard_stack(void) {
1544 return reguard_stack(os::current_stack_pointer());
1545 }
1546
1547
1548 void JavaThread::block_if_vm_exited() {
1549 if (_terminated == _vm_exited) {
1550 // _vm_exited is set at safepoint, and Threads_lock is never released
1551 // we will block here forever
1552 Threads_lock->lock_without_safepoint_check();
1553 ShouldNotReachHere();
1554 }
1555 }
1556
1557
1558 // Remove this ifdef when C1 is ported to the compiler interface.
1559 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1560
1561 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1562 Thread()
1563 #if INCLUDE_ALL_GCS
1564 , _satb_mark_queue(&_satb_mark_queue_set),
1565 _dirty_card_queue(&_dirty_card_queue_set)
1566 #endif // INCLUDE_ALL_GCS
1567 {
1568 if (TraceThreadEvents) {
1569 tty->print_cr("creating thread %p", this);
1570 }
1571 initialize();
1572 _jni_attach_state = _not_attaching_via_jni;
1573 set_entry_point(entry_point);
1574 // Create the native thread itself.
1575 // %note runtime_23
1576 os::ThreadType thr_type = os::java_thread;
1577 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1578 os::java_thread;
1579 os::create_thread(this, thr_type, stack_sz);
1580 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1581 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1582 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1583 // the exception consists of creating the exception object & initializing it, initialization
1584 // will leave the VM via a JavaCall and then all locks must be unlocked).
1585 //
1586 // The thread is still suspended when we reach here. Thread must be explicit started
1587 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1588 // by calling Threads:add. The reason why this is not done here, is because the thread
1589 // object must be fully initialized (take a look at JVM_Start)
1590 }
1591
1592 JavaThread::~JavaThread() {
1593 if (TraceThreadEvents) {
1594 tty->print_cr("terminate thread %p", this);
1595 }
1596
1597 // JSR166 -- return the parker to the free list
1598 Parker::Release(_parker);
1599 _parker = NULL ;
1600
1601 // Free any remaining previous UnrollBlock
1602 vframeArray* old_array = vframe_array_last();
1603
1604 if (old_array != NULL) {
1605 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1606 old_array->set_unroll_block(NULL);
1607 delete old_info;
1608 delete old_array;
1609 }
1610
1611 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1612 if (deferred != NULL) {
1613 // This can only happen if thread is destroyed before deoptimization occurs.
1614 assert(deferred->length() != 0, "empty array!");
1615 do {
1616 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1617 deferred->remove_at(0);
1618 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1619 delete dlv;
1620 } while (deferred->length() != 0);
1621 delete deferred;
1622 }
1623
1624 // All Java related clean up happens in exit
1625 ThreadSafepointState::destroy(this);
1626 if (_thread_profiler != NULL) delete _thread_profiler;
1627 if (_thread_stat != NULL) delete _thread_stat;
1628 }
1629
1630
1631 // The first routine called by a new Java thread
1632 void JavaThread::run() {
1633 // initialize thread-local alloc buffer related fields
1634 this->initialize_tlab();
1635
1636 // used to test validitity of stack trace backs
1637 this->record_base_of_stack_pointer();
1638
1639 // Record real stack base and size.
1640 this->record_stack_base_and_size();
1641
1642 // Initialize thread local storage; set before calling MutexLocker
1643 this->initialize_thread_local_storage();
1644
1645 this->create_stack_guard_pages();
1646
1647 this->cache_global_variables();
1648
1649 // Thread is now sufficient initialized to be handled by the safepoint code as being
1650 // in the VM. Change thread state from _thread_new to _thread_in_vm
1651 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1652
1653 assert(JavaThread::current() == this, "sanity check");
1654 assert(!Thread::current()->owns_locks(), "sanity check");
1655
1656 DTRACE_THREAD_PROBE(start, this);
1657
1658 // This operation might block. We call that after all safepoint checks for a new thread has
1659 // been completed.
1660 this->set_active_handles(JNIHandleBlock::allocate_block());
1661
1662 if (JvmtiExport::should_post_thread_life()) {
1663 JvmtiExport::post_thread_start(this);
1664 }
1665
1666 EventThreadStart event;
1667 if (event.should_commit()) {
1668 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1669 event.commit();
1670 }
1671
1672 // We call another function to do the rest so we are sure that the stack addresses used
1673 // from there will be lower than the stack base just computed
1674 thread_main_inner();
1675
1676 // Note, thread is no longer valid at this point!
1677 }
1678
1679
1680 void JavaThread::thread_main_inner() {
1681 assert(JavaThread::current() == this, "sanity check");
1682 assert(this->threadObj() != NULL, "just checking");
1683
1684 // Execute thread entry point unless this thread has a pending exception
1685 // or has been stopped before starting.
1686 // Note: Due to JVM_StopThread we can have pending exceptions already!
1687 if (!this->has_pending_exception() &&
1688 !java_lang_Thread::is_stillborn(this->threadObj())) {
1689 {
1690 ResourceMark rm(this);
1691 this->set_native_thread_name(this->get_thread_name());
1692 }
1693 HandleMark hm(this);
1694 this->entry_point()(this, this);
1695 }
1696
1697 DTRACE_THREAD_PROBE(stop, this);
1698
1699 this->exit(false);
1700 delete this;
1701 }
1702
1703
1704 static void ensure_join(JavaThread* thread) {
1705 // We do not need to grap the Threads_lock, since we are operating on ourself.
1706 Handle threadObj(thread, thread->threadObj());
1707 assert(threadObj.not_null(), "java thread object must exist");
1708 ObjectLocker lock(threadObj, thread);
1709 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1710 thread->clear_pending_exception();
1711 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1712 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1713 // Clear the native thread instance - this makes isAlive return false and allows the join()
1714 // to complete once we've done the notify_all below
1715 java_lang_Thread::set_thread(threadObj(), NULL);
1716 lock.notify_all(thread);
1717 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1718 thread->clear_pending_exception();
1719 }
1720
1721
1722 // For any new cleanup additions, please check to see if they need to be applied to
1723 // cleanup_failed_attach_current_thread as well.
1724 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1725 assert(this == JavaThread::current(), "thread consistency check");
1726
1727 HandleMark hm(this);
1728 Handle uncaught_exception(this, this->pending_exception());
1729 this->clear_pending_exception();
1730 Handle threadObj(this, this->threadObj());
1731 assert(threadObj.not_null(), "Java thread object should be created");
1732
1733 if (get_thread_profiler() != NULL) {
1734 get_thread_profiler()->disengage();
1735 ResourceMark rm;
1736 get_thread_profiler()->print(get_thread_name());
1737 }
1738
1739
1740 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1741 {
1742 EXCEPTION_MARK;
1743
1744 CLEAR_PENDING_EXCEPTION;
1745 }
1746 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1747 // has to be fixed by a runtime query method
1748 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1749 // JSR-166: change call from from ThreadGroup.uncaughtException to
1750 // java.lang.Thread.dispatchUncaughtException
1751 if (uncaught_exception.not_null()) {
1752 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1753 {
1754 EXCEPTION_MARK;
1755 // Check if the method Thread.dispatchUncaughtException() exists. If so
1756 // call it. Otherwise we have an older library without the JSR-166 changes,
1757 // so call ThreadGroup.uncaughtException()
1758 KlassHandle recvrKlass(THREAD, threadObj->klass());
1759 CallInfo callinfo;
1760 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1761 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1762 vmSymbols::dispatchUncaughtException_name(),
1763 vmSymbols::throwable_void_signature(),
1764 KlassHandle(), false, false, THREAD);
1765 CLEAR_PENDING_EXCEPTION;
1766 methodHandle method = callinfo.selected_method();
1767 if (method.not_null()) {
1768 JavaValue result(T_VOID);
1769 JavaCalls::call_virtual(&result,
1770 threadObj, thread_klass,
1771 vmSymbols::dispatchUncaughtException_name(),
1772 vmSymbols::throwable_void_signature(),
1773 uncaught_exception,
1774 THREAD);
1775 } else {
1776 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1777 JavaValue result(T_VOID);
1778 JavaCalls::call_virtual(&result,
1779 group, thread_group,
1780 vmSymbols::uncaughtException_name(),
1781 vmSymbols::thread_throwable_void_signature(),
1782 threadObj, // Arg 1
1783 uncaught_exception, // Arg 2
1784 THREAD);
1785 }
1786 if (HAS_PENDING_EXCEPTION) {
1787 ResourceMark rm(this);
1788 jio_fprintf(defaultStream::error_stream(),
1789 "\nException: %s thrown from the UncaughtExceptionHandler"
1790 " in thread \"%s\"\n",
1791 pending_exception()->klass()->external_name(),
1792 get_thread_name());
1793 CLEAR_PENDING_EXCEPTION;
1794 }
1795 }
1796 }
1797
1798 // Called before the java thread exit since we want to read info
1799 // from java_lang_Thread object
1800 EventThreadEnd event;
1801 if (event.should_commit()) {
1802 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1803 event.commit();
1804 }
1805
1806 // Call after last event on thread
1807 EVENT_THREAD_EXIT(this);
1808
1809 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1810 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1811 // is deprecated anyhow.
1812 if (!is_Compiler_thread()) {
1813 int count = 3;
1814 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1815 EXCEPTION_MARK;
1816 JavaValue result(T_VOID);
1817 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1818 JavaCalls::call_virtual(&result,
1819 threadObj, thread_klass,
1820 vmSymbols::exit_method_name(),
1821 vmSymbols::void_method_signature(),
1822 THREAD);
1823 CLEAR_PENDING_EXCEPTION;
1824 }
1825 }
1826 // notify JVMTI
1827 if (JvmtiExport::should_post_thread_life()) {
1828 JvmtiExport::post_thread_end(this);
1829 }
1830
1831 // We have notified the agents that we are exiting, before we go on,
1832 // we must check for a pending external suspend request and honor it
1833 // in order to not surprise the thread that made the suspend request.
1834 while (true) {
1835 {
1836 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1837 if (!is_external_suspend()) {
1838 set_terminated(_thread_exiting);
1839 ThreadService::current_thread_exiting(this);
1840 break;
1841 }
1842 // Implied else:
1843 // Things get a little tricky here. We have a pending external
1844 // suspend request, but we are holding the SR_lock so we
1845 // can't just self-suspend. So we temporarily drop the lock
1846 // and then self-suspend.
1847 }
1848
1849 ThreadBlockInVM tbivm(this);
1850 java_suspend_self();
1851
1852 // We're done with this suspend request, but we have to loop around
1853 // and check again. Eventually we will get SR_lock without a pending
1854 // external suspend request and will be able to mark ourselves as
1855 // exiting.
1856 }
1857 // no more external suspends are allowed at this point
1858 } else {
1859 // before_exit() has already posted JVMTI THREAD_END events
1860 }
1861
1862 // Notify waiters on thread object. This has to be done after exit() is called
1863 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1864 // group should have the destroyed bit set before waiters are notified).
1865 ensure_join(this);
1866 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1867
1868 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1869 // held by this thread must be released. A detach operation must only
1870 // get here if there are no Java frames on the stack. Therefore, any
1871 // owned monitors at this point MUST be JNI-acquired monitors which are
1872 // pre-inflated and in the monitor cache.
1873 //
1874 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1875 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1876 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1877 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1878 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1879 }
1880
1881 // These things needs to be done while we are still a Java Thread. Make sure that thread
1882 // is in a consistent state, in case GC happens
1883 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1884
1885 if (active_handles() != NULL) {
1886 JNIHandleBlock* block = active_handles();
1887 set_active_handles(NULL);
1888 JNIHandleBlock::release_block(block);
1889 }
1890
1891 if (free_handle_block() != NULL) {
1892 JNIHandleBlock* block = free_handle_block();
1893 set_free_handle_block(NULL);
1894 JNIHandleBlock::release_block(block);
1895 }
1896
1897 // These have to be removed while this is still a valid thread.
1898 remove_stack_guard_pages();
1899
1900 if (UseTLAB) {
1901 tlab().make_parsable(true); // retire TLAB
1902 }
1903
1904 if (JvmtiEnv::environments_might_exist()) {
1905 JvmtiExport::cleanup_thread(this);
1906 }
1907
1908 // We must flush any deferred card marks before removing a thread from
1909 // the list of active threads.
1910 Universe::heap()->flush_deferred_store_barrier(this);
1911 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1912
1913 #if INCLUDE_ALL_GCS
1914 // We must flush the G1-related buffers before removing a thread
1915 // from the list of active threads. We must do this after any deferred
1916 // card marks have been flushed (above) so that any entries that are
1917 // added to the thread's dirty card queue as a result are not lost.
1918 if (UseG1GC) {
1919 flush_barrier_queues();
1920 }
1921 #endif // INCLUDE_ALL_GCS
1922
1923 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1924 Threads::remove(this);
1925 }
1926
1927 #if INCLUDE_ALL_GCS
1928 // Flush G1-related queues.
1929 void JavaThread::flush_barrier_queues() {
1930 satb_mark_queue().flush();
1931 dirty_card_queue().flush();
1932 }
1933
1934 void JavaThread::initialize_queues() {
1935 assert(!SafepointSynchronize::is_at_safepoint(),
1936 "we should not be at a safepoint");
1937
1938 ObjPtrQueue& satb_queue = satb_mark_queue();
1939 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1940 // The SATB queue should have been constructed with its active
1941 // field set to false.
1942 assert(!satb_queue.is_active(), "SATB queue should not be active");
1943 assert(satb_queue.is_empty(), "SATB queue should be empty");
1944 // If we are creating the thread during a marking cycle, we should
1945 // set the active field of the SATB queue to true.
1946 if (satb_queue_set.is_active()) {
1947 satb_queue.set_active(true);
1948 }
1949
1950 DirtyCardQueue& dirty_queue = dirty_card_queue();
1951 // The dirty card queue should have been constructed with its
1952 // active field set to true.
1953 assert(dirty_queue.is_active(), "dirty card queue should be active");
1954 }
1955 #endif // INCLUDE_ALL_GCS
1956
1957 void JavaThread::cleanup_failed_attach_current_thread() {
1958 if (get_thread_profiler() != NULL) {
1959 get_thread_profiler()->disengage();
1960 ResourceMark rm;
1961 get_thread_profiler()->print(get_thread_name());
1962 }
1963
1964 if (active_handles() != NULL) {
1965 JNIHandleBlock* block = active_handles();
1966 set_active_handles(NULL);
1967 JNIHandleBlock::release_block(block);
1968 }
1969
1970 if (free_handle_block() != NULL) {
1971 JNIHandleBlock* block = free_handle_block();
1972 set_free_handle_block(NULL);
1973 JNIHandleBlock::release_block(block);
1974 }
1975
1976 // These have to be removed while this is still a valid thread.
1977 remove_stack_guard_pages();
1978
1979 if (UseTLAB) {
1980 tlab().make_parsable(true); // retire TLAB, if any
1981 }
1982
1983 #if INCLUDE_ALL_GCS
1984 if (UseG1GC) {
1985 flush_barrier_queues();
1986 }
1987 #endif // INCLUDE_ALL_GCS
1988
1989 Threads::remove(this);
1990 delete this;
1991 }
1992
1993
1994
1995
1996 JavaThread* JavaThread::active() {
1997 Thread* thread = ThreadLocalStorage::thread();
1998 assert(thread != NULL, "just checking");
1999 if (thread->is_Java_thread()) {
2000 return (JavaThread*) thread;
2001 } else {
2002 assert(thread->is_VM_thread(), "this must be a vm thread");
2003 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2004 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2005 assert(ret->is_Java_thread(), "must be a Java thread");
2006 return ret;
2007 }
2008 }
2009
2010 bool JavaThread::is_lock_owned(address adr) const {
2011 if (Thread::is_lock_owned(adr)) return true;
2012
2013 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2014 if (chunk->contains(adr)) return true;
2015 }
2016
2017 return false;
2018 }
2019
2020
2021 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2022 chunk->set_next(monitor_chunks());
2023 set_monitor_chunks(chunk);
2024 }
2025
2026 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2027 guarantee(monitor_chunks() != NULL, "must be non empty");
2028 if (monitor_chunks() == chunk) {
2029 set_monitor_chunks(chunk->next());
2030 } else {
2031 MonitorChunk* prev = monitor_chunks();
2032 while (prev->next() != chunk) prev = prev->next();
2033 prev->set_next(chunk->next());
2034 }
2035 }
2036
2037 // JVM support.
2038
2039 // Note: this function shouldn't block if it's called in
2040 // _thread_in_native_trans state (such as from
2041 // check_special_condition_for_native_trans()).
2042 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2043
2044 if (has_last_Java_frame() && has_async_condition()) {
2045 // If we are at a polling page safepoint (not a poll return)
2046 // then we must defer async exception because live registers
2047 // will be clobbered by the exception path. Poll return is
2048 // ok because the call we a returning from already collides
2049 // with exception handling registers and so there is no issue.
2050 // (The exception handling path kills call result registers but
2051 // this is ok since the exception kills the result anyway).
2052
2053 if (is_at_poll_safepoint()) {
2054 // if the code we are returning to has deoptimized we must defer
2055 // the exception otherwise live registers get clobbered on the
2056 // exception path before deoptimization is able to retrieve them.
2057 //
2058 RegisterMap map(this, false);
2059 frame caller_fr = last_frame().sender(&map);
2060 assert(caller_fr.is_compiled_frame(), "what?");
2061 if (caller_fr.is_deoptimized_frame()) {
2062 if (TraceExceptions) {
2063 ResourceMark rm;
2064 tty->print_cr("deferred async exception at compiled safepoint");
2065 }
2066 return;
2067 }
2068 }
2069 }
2070
2071 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2072 if (condition == _no_async_condition) {
2073 // Conditions have changed since has_special_runtime_exit_condition()
2074 // was called:
2075 // - if we were here only because of an external suspend request,
2076 // then that was taken care of above (or cancelled) so we are done
2077 // - if we were here because of another async request, then it has
2078 // been cleared between the has_special_runtime_exit_condition()
2079 // and now so again we are done
2080 return;
2081 }
2082
2083 // Check for pending async. exception
2084 if (_pending_async_exception != NULL) {
2085 // Only overwrite an already pending exception, if it is not a threadDeath.
2086 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2087
2088 // We cannot call Exceptions::_throw(...) here because we cannot block
2089 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2090
2091 if (TraceExceptions) {
2092 ResourceMark rm;
2093 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2094 if (has_last_Java_frame() ) {
2095 frame f = last_frame();
2096 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2097 }
2098 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2099 }
2100 _pending_async_exception = NULL;
2101 clear_has_async_exception();
2102 }
2103 }
2104
2105 if (check_unsafe_error &&
2106 condition == _async_unsafe_access_error && !has_pending_exception()) {
2107 condition = _no_async_condition; // done
2108 switch (thread_state()) {
2109 case _thread_in_vm:
2110 {
2111 JavaThread* THREAD = this;
2112 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2113 }
2114 case _thread_in_native:
2115 {
2116 ThreadInVMfromNative tiv(this);
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_Java:
2121 {
2122 ThreadInVMfromJava tiv(this);
2123 JavaThread* THREAD = this;
2124 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2125 }
2126 default:
2127 ShouldNotReachHere();
2128 }
2129 }
2130
2131 assert(condition == _no_async_condition || has_pending_exception() ||
2132 (!check_unsafe_error && condition == _async_unsafe_access_error),
2133 "must have handled the async condition, if no exception");
2134 }
2135
2136 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2137 //
2138 // Check for pending external suspend. Internal suspend requests do
2139 // not use handle_special_runtime_exit_condition().
2140 // If JNIEnv proxies are allowed, don't self-suspend if the target
2141 // thread is not the current thread. In older versions of jdbx, jdbx
2142 // threads could call into the VM with another thread's JNIEnv so we
2143 // can be here operating on behalf of a suspended thread (4432884).
2144 bool do_self_suspend = is_external_suspend_with_lock();
2145 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2146 //
2147 // Because thread is external suspended the safepoint code will count
2148 // thread as at a safepoint. This can be odd because we can be here
2149 // as _thread_in_Java which would normally transition to _thread_blocked
2150 // at a safepoint. We would like to mark the thread as _thread_blocked
2151 // before calling java_suspend_self like all other callers of it but
2152 // we must then observe proper safepoint protocol. (We can't leave
2153 // _thread_blocked with a safepoint in progress). However we can be
2154 // here as _thread_in_native_trans so we can't use a normal transition
2155 // constructor/destructor pair because they assert on that type of
2156 // transition. We could do something like:
2157 //
2158 // JavaThreadState state = thread_state();
2159 // set_thread_state(_thread_in_vm);
2160 // {
2161 // ThreadBlockInVM tbivm(this);
2162 // java_suspend_self()
2163 // }
2164 // set_thread_state(_thread_in_vm_trans);
2165 // if (safepoint) block;
2166 // set_thread_state(state);
2167 //
2168 // but that is pretty messy. Instead we just go with the way the
2169 // code has worked before and note that this is the only path to
2170 // java_suspend_self that doesn't put the thread in _thread_blocked
2171 // mode.
2172
2173 frame_anchor()->make_walkable(this);
2174 java_suspend_self();
2175
2176 // We might be here for reasons in addition to the self-suspend request
2177 // so check for other async requests.
2178 }
2179
2180 if (check_asyncs) {
2181 check_and_handle_async_exceptions();
2182 }
2183 }
2184
2185 void JavaThread::send_thread_stop(oop java_throwable) {
2186 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2187 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2188 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2189
2190 // Do not throw asynchronous exceptions against the compiler thread
2191 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2192 if (is_Compiler_thread()) return;
2193
2194 {
2195 // Actually throw the Throwable against the target Thread - however
2196 // only if there is no thread death exception installed already.
2197 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2198 // If the topmost frame is a runtime stub, then we are calling into
2199 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2200 // must deoptimize the caller before continuing, as the compiled exception handler table
2201 // may not be valid
2202 if (has_last_Java_frame()) {
2203 frame f = last_frame();
2204 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2205 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2206 RegisterMap reg_map(this, UseBiasedLocking);
2207 frame compiled_frame = f.sender(®_map);
2208 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2209 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2210 }
2211 }
2212 }
2213
2214 // Set async. pending exception in thread.
2215 set_pending_async_exception(java_throwable);
2216
2217 if (TraceExceptions) {
2218 ResourceMark rm;
2219 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2220 }
2221 // for AbortVMOnException flag
2222 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2223 }
2224 }
2225
2226
2227 // Interrupt thread so it will wake up from a potential wait()
2228 Thread::interrupt(this);
2229 }
2230
2231 // External suspension mechanism.
2232 //
2233 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2234 // to any VM_locks and it is at a transition
2235 // Self-suspension will happen on the transition out of the vm.
2236 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2237 //
2238 // Guarantees on return:
2239 // + Target thread will not execute any new bytecode (that's why we need to
2240 // force a safepoint)
2241 // + Target thread will not enter any new monitors
2242 //
2243 void JavaThread::java_suspend() {
2244 { MutexLocker mu(Threads_lock);
2245 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2246 return;
2247 }
2248 }
2249
2250 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2251 if (!is_external_suspend()) {
2252 // a racing resume has cancelled us; bail out now
2253 return;
2254 }
2255
2256 // suspend is done
2257 uint32_t debug_bits = 0;
2258 // Warning: is_ext_suspend_completed() may temporarily drop the
2259 // SR_lock to allow the thread to reach a stable thread state if
2260 // it is currently in a transient thread state.
2261 if (is_ext_suspend_completed(false /* !called_by_wait */,
2262 SuspendRetryDelay, &debug_bits) ) {
2263 return;
2264 }
2265 }
2266
2267 VM_ForceSafepoint vm_suspend;
2268 VMThread::execute(&vm_suspend);
2269 }
2270
2271 // Part II of external suspension.
2272 // A JavaThread self suspends when it detects a pending external suspend
2273 // request. This is usually on transitions. It is also done in places
2274 // where continuing to the next transition would surprise the caller,
2275 // e.g., monitor entry.
2276 //
2277 // Returns the number of times that the thread self-suspended.
2278 //
2279 // Note: DO NOT call java_suspend_self() when you just want to block current
2280 // thread. java_suspend_self() is the second stage of cooperative
2281 // suspension for external suspend requests and should only be used
2282 // to complete an external suspend request.
2283 //
2284 int JavaThread::java_suspend_self() {
2285 int ret = 0;
2286
2287 // we are in the process of exiting so don't suspend
2288 if (is_exiting()) {
2289 clear_external_suspend();
2290 return ret;
2291 }
2292
2293 assert(_anchor.walkable() ||
2294 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2295 "must have walkable stack");
2296
2297 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2298
2299 assert(!this->is_ext_suspended(),
2300 "a thread trying to self-suspend should not already be suspended");
2301
2302 if (this->is_suspend_equivalent()) {
2303 // If we are self-suspending as a result of the lifting of a
2304 // suspend equivalent condition, then the suspend_equivalent
2305 // flag is not cleared until we set the ext_suspended flag so
2306 // that wait_for_ext_suspend_completion() returns consistent
2307 // results.
2308 this->clear_suspend_equivalent();
2309 }
2310
2311 // A racing resume may have cancelled us before we grabbed SR_lock
2312 // above. Or another external suspend request could be waiting for us
2313 // by the time we return from SR_lock()->wait(). The thread
2314 // that requested the suspension may already be trying to walk our
2315 // stack and if we return now, we can change the stack out from under
2316 // it. This would be a "bad thing (TM)" and cause the stack walker
2317 // to crash. We stay self-suspended until there are no more pending
2318 // external suspend requests.
2319 while (is_external_suspend()) {
2320 ret++;
2321 this->set_ext_suspended();
2322
2323 // _ext_suspended flag is cleared by java_resume()
2324 while (is_ext_suspended()) {
2325 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2326 }
2327 }
2328
2329 return ret;
2330 }
2331
2332 #ifdef ASSERT
2333 // verify the JavaThread has not yet been published in the Threads::list, and
2334 // hence doesn't need protection from concurrent access at this stage
2335 void JavaThread::verify_not_published() {
2336 if (!Threads_lock->owned_by_self()) {
2337 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2338 assert( !Threads::includes(this),
2339 "java thread shouldn't have been published yet!");
2340 }
2341 else {
2342 assert( !Threads::includes(this),
2343 "java thread shouldn't have been published yet!");
2344 }
2345 }
2346 #endif
2347
2348 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2349 // progress or when _suspend_flags is non-zero.
2350 // Current thread needs to self-suspend if there is a suspend request and/or
2351 // block if a safepoint is in progress.
2352 // Async exception ISN'T checked.
2353 // Note only the ThreadInVMfromNative transition can call this function
2354 // directly and when thread state is _thread_in_native_trans
2355 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2356 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2357
2358 JavaThread *curJT = JavaThread::current();
2359 bool do_self_suspend = thread->is_external_suspend();
2360
2361 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2362
2363 // If JNIEnv proxies are allowed, don't self-suspend if the target
2364 // thread is not the current thread. In older versions of jdbx, jdbx
2365 // threads could call into the VM with another thread's JNIEnv so we
2366 // can be here operating on behalf of a suspended thread (4432884).
2367 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2368 JavaThreadState state = thread->thread_state();
2369
2370 // We mark this thread_blocked state as a suspend-equivalent so
2371 // that a caller to is_ext_suspend_completed() won't be confused.
2372 // The suspend-equivalent state is cleared by java_suspend_self().
2373 thread->set_suspend_equivalent();
2374
2375 // If the safepoint code sees the _thread_in_native_trans state, it will
2376 // wait until the thread changes to other thread state. There is no
2377 // guarantee on how soon we can obtain the SR_lock and complete the
2378 // self-suspend request. It would be a bad idea to let safepoint wait for
2379 // too long. Temporarily change the state to _thread_blocked to
2380 // let the VM thread know that this thread is ready for GC. The problem
2381 // of changing thread state is that safepoint could happen just after
2382 // java_suspend_self() returns after being resumed, and VM thread will
2383 // see the _thread_blocked state. We must check for safepoint
2384 // after restoring the state and make sure we won't leave while a safepoint
2385 // is in progress.
2386 thread->set_thread_state(_thread_blocked);
2387 thread->java_suspend_self();
2388 thread->set_thread_state(state);
2389 // Make sure new state is seen by VM thread
2390 if (os::is_MP()) {
2391 if (UseMembar) {
2392 // Force a fence between the write above and read below
2393 OrderAccess::fence();
2394 } else {
2395 // Must use this rather than serialization page in particular on Windows
2396 InterfaceSupport::serialize_memory(thread);
2397 }
2398 }
2399 }
2400
2401 if (SafepointSynchronize::do_call_back()) {
2402 // If we are safepointing, then block the caller which may not be
2403 // the same as the target thread (see above).
2404 SafepointSynchronize::block(curJT);
2405 }
2406
2407 if (thread->is_deopt_suspend()) {
2408 thread->clear_deopt_suspend();
2409 RegisterMap map(thread, false);
2410 frame f = thread->last_frame();
2411 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2412 f = f.sender(&map);
2413 }
2414 if (f.id() == thread->must_deopt_id()) {
2415 thread->clear_must_deopt_id();
2416 f.deoptimize(thread);
2417 } else {
2418 fatal("missed deoptimization!");
2419 }
2420 }
2421 }
2422
2423 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2424 // progress or when _suspend_flags is non-zero.
2425 // Current thread needs to self-suspend if there is a suspend request and/or
2426 // block if a safepoint is in progress.
2427 // Also check for pending async exception (not including unsafe access error).
2428 // Note only the native==>VM/Java barriers can call this function and when
2429 // thread state is _thread_in_native_trans.
2430 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2431 check_safepoint_and_suspend_for_native_trans(thread);
2432
2433 if (thread->has_async_exception()) {
2434 // We are in _thread_in_native_trans state, don't handle unsafe
2435 // access error since that may block.
2436 thread->check_and_handle_async_exceptions(false);
2437 }
2438 }
2439
2440 // This is a variant of the normal
2441 // check_special_condition_for_native_trans with slightly different
2442 // semantics for use by critical native wrappers. It does all the
2443 // normal checks but also performs the transition back into
2444 // thread_in_Java state. This is required so that critical natives
2445 // can potentially block and perform a GC if they are the last thread
2446 // exiting the GC_locker.
2447 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2448 check_special_condition_for_native_trans(thread);
2449
2450 // Finish the transition
2451 thread->set_thread_state(_thread_in_Java);
2452
2453 if (thread->do_critical_native_unlock()) {
2454 ThreadInVMfromJavaNoAsyncException tiv(thread);
2455 GC_locker::unlock_critical(thread);
2456 thread->clear_critical_native_unlock();
2457 }
2458 }
2459
2460 // We need to guarantee the Threads_lock here, since resumes are not
2461 // allowed during safepoint synchronization
2462 // Can only resume from an external suspension
2463 void JavaThread::java_resume() {
2464 assert_locked_or_safepoint(Threads_lock);
2465
2466 // Sanity check: thread is gone, has started exiting or the thread
2467 // was not externally suspended.
2468 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2469 return;
2470 }
2471
2472 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2473
2474 clear_external_suspend();
2475
2476 if (is_ext_suspended()) {
2477 clear_ext_suspended();
2478 SR_lock()->notify_all();
2479 }
2480 }
2481
2482 void JavaThread::create_stack_guard_pages() {
2483 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2484 address low_addr = stack_base() - stack_size();
2485 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2486
2487 int allocate = os::allocate_stack_guard_pages();
2488 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2489
2490 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2491 warning("Attempt to allocate stack guard pages failed.");
2492 return;
2493 }
2494
2495 if (os::guard_memory((char *) low_addr, len)) {
2496 _stack_guard_state = stack_guard_enabled;
2497 } else {
2498 warning("Attempt to protect stack guard pages failed.");
2499 if (os::uncommit_memory((char *) low_addr, len)) {
2500 warning("Attempt to deallocate stack guard pages failed.");
2501 }
2502 }
2503 }
2504
2505 void JavaThread::remove_stack_guard_pages() {
2506 assert(Thread::current() == this, "from different thread");
2507 if (_stack_guard_state == stack_guard_unused) return;
2508 address low_addr = stack_base() - stack_size();
2509 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2510
2511 if (os::allocate_stack_guard_pages()) {
2512 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2513 _stack_guard_state = stack_guard_unused;
2514 } else {
2515 warning("Attempt to deallocate stack guard pages failed.");
2516 }
2517 } else {
2518 if (_stack_guard_state == stack_guard_unused) return;
2519 if (os::unguard_memory((char *) low_addr, len)) {
2520 _stack_guard_state = stack_guard_unused;
2521 } else {
2522 warning("Attempt to unprotect stack guard pages failed.");
2523 }
2524 }
2525 }
2526
2527 void JavaThread::enable_stack_yellow_zone() {
2528 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2529 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2530
2531 // The base notation is from the stacks point of view, growing downward.
2532 // We need to adjust it to work correctly with guard_memory()
2533 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2534
2535 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2536 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2537
2538 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2539 _stack_guard_state = stack_guard_enabled;
2540 } else {
2541 warning("Attempt to guard stack yellow zone failed.");
2542 }
2543 enable_register_stack_guard();
2544 }
2545
2546 void JavaThread::disable_stack_yellow_zone() {
2547 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2548 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2549
2550 // Simply return if called for a thread that does not use guard pages.
2551 if (_stack_guard_state == stack_guard_unused) return;
2552
2553 // The base notation is from the stacks point of view, growing downward.
2554 // We need to adjust it to work correctly with guard_memory()
2555 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2556
2557 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2558 _stack_guard_state = stack_guard_yellow_disabled;
2559 } else {
2560 warning("Attempt to unguard stack yellow zone failed.");
2561 }
2562 disable_register_stack_guard();
2563 }
2564
2565 void JavaThread::enable_stack_red_zone() {
2566 // The base notation is from the stacks point of view, growing downward.
2567 // We need to adjust it to work correctly with guard_memory()
2568 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2569 address base = stack_red_zone_base() - stack_red_zone_size();
2570
2571 guarantee(base < stack_base(),"Error calculating stack red zone");
2572 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2573
2574 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2575 warning("Attempt to guard stack red zone failed.");
2576 }
2577 }
2578
2579 void JavaThread::disable_stack_red_zone() {
2580 // The base notation is from the stacks point of view, growing downward.
2581 // We need to adjust it to work correctly with guard_memory()
2582 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2583 address base = stack_red_zone_base() - stack_red_zone_size();
2584 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2585 warning("Attempt to unguard stack red zone failed.");
2586 }
2587 }
2588
2589 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2590 // ignore is there is no stack
2591 if (!has_last_Java_frame()) return;
2592 // traverse the stack frames. Starts from top frame.
2593 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2594 frame* fr = fst.current();
2595 f(fr, fst.register_map());
2596 }
2597 }
2598
2599
2600 #ifndef PRODUCT
2601 // Deoptimization
2602 // Function for testing deoptimization
2603 void JavaThread::deoptimize() {
2604 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2605 StackFrameStream fst(this, UseBiasedLocking);
2606 bool deopt = false; // Dump stack only if a deopt actually happens.
2607 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2608 // Iterate over all frames in the thread and deoptimize
2609 for(; !fst.is_done(); fst.next()) {
2610 if(fst.current()->can_be_deoptimized()) {
2611
2612 if (only_at) {
2613 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2614 // consists of comma or carriage return separated numbers so
2615 // search for the current bci in that string.
2616 address pc = fst.current()->pc();
2617 nmethod* nm = (nmethod*) fst.current()->cb();
2618 ScopeDesc* sd = nm->scope_desc_at( pc);
2619 char buffer[8];
2620 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2621 size_t len = strlen(buffer);
2622 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2623 while (found != NULL) {
2624 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2625 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2626 // Check that the bci found is bracketed by terminators.
2627 break;
2628 }
2629 found = strstr(found + 1, buffer);
2630 }
2631 if (!found) {
2632 continue;
2633 }
2634 }
2635
2636 if (DebugDeoptimization && !deopt) {
2637 deopt = true; // One-time only print before deopt
2638 tty->print_cr("[BEFORE Deoptimization]");
2639 trace_frames();
2640 trace_stack();
2641 }
2642 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2643 }
2644 }
2645
2646 if (DebugDeoptimization && deopt) {
2647 tty->print_cr("[AFTER Deoptimization]");
2648 trace_frames();
2649 }
2650 }
2651
2652
2653 // Make zombies
2654 void JavaThread::make_zombies() {
2655 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2656 if (fst.current()->can_be_deoptimized()) {
2657 // it is a Java nmethod
2658 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2659 nm->make_not_entrant();
2660 }
2661 }
2662 }
2663 #endif // PRODUCT
2664
2665
2666 void JavaThread::deoptimized_wrt_marked_nmethods() {
2667 if (!has_last_Java_frame()) return;
2668 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2669 StackFrameStream fst(this, UseBiasedLocking);
2670 for(; !fst.is_done(); fst.next()) {
2671 if (fst.current()->should_be_deoptimized()) {
2672 if (LogCompilation && xtty != NULL) {
2673 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2674 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2675 this->name(), nm != NULL ? nm->compile_id() : -1);
2676 }
2677
2678 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2679 }
2680 }
2681 }
2682
2683
2684 // GC support
2685 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2686
2687 void JavaThread::gc_epilogue() {
2688 frames_do(frame_gc_epilogue);
2689 }
2690
2691
2692 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2693
2694 void JavaThread::gc_prologue() {
2695 frames_do(frame_gc_prologue);
2696 }
2697
2698 // If the caller is a NamedThread, then remember, in the current scope,
2699 // the given JavaThread in its _processed_thread field.
2700 class RememberProcessedThread: public StackObj {
2701 NamedThread* _cur_thr;
2702 public:
2703 RememberProcessedThread(JavaThread* jthr) {
2704 Thread* thread = Thread::current();
2705 if (thread->is_Named_thread()) {
2706 _cur_thr = (NamedThread *)thread;
2707 _cur_thr->set_processed_thread(jthr);
2708 } else {
2709 _cur_thr = NULL;
2710 }
2711 }
2712
2713 ~RememberProcessedThread() {
2714 if (_cur_thr) {
2715 _cur_thr->set_processed_thread(NULL);
2716 }
2717 }
2718 };
2719
2720 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2721 // Verify that the deferred card marks have been flushed.
2722 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2723
2724 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2725 // since there may be more than one thread using each ThreadProfiler.
2726
2727 // Traverse the GCHandles
2728 Thread::oops_do(f, cld_f, cf);
2729
2730 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2731 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2732
2733 if (has_last_Java_frame()) {
2734 // Record JavaThread to GC thread
2735 RememberProcessedThread rpt(this);
2736
2737 // Traverse the privileged stack
2738 if (_privileged_stack_top != NULL) {
2739 _privileged_stack_top->oops_do(f);
2740 }
2741
2742 // traverse the registered growable array
2743 if (_array_for_gc != NULL) {
2744 for (int index = 0; index < _array_for_gc->length(); index++) {
2745 f->do_oop(_array_for_gc->adr_at(index));
2746 }
2747 }
2748
2749 // Traverse the monitor chunks
2750 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2751 chunk->oops_do(f);
2752 }
2753
2754 // Traverse the execution stack
2755 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2756 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2757 }
2758 }
2759
2760 // callee_target is never live across a gc point so NULL it here should
2761 // it still contain a methdOop.
2762
2763 set_callee_target(NULL);
2764
2765 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2766 // If we have deferred set_locals there might be oops waiting to be
2767 // written
2768 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2769 if (list != NULL) {
2770 for (int i = 0; i < list->length(); i++) {
2771 list->at(i)->oops_do(f);
2772 }
2773 }
2774
2775 // Traverse instance variables at the end since the GC may be moving things
2776 // around using this function
2777 f->do_oop((oop*) &_threadObj);
2778 f->do_oop((oop*) &_vm_result);
2779 f->do_oop((oop*) &_exception_oop);
2780 f->do_oop((oop*) &_pending_async_exception);
2781
2782 if (jvmti_thread_state() != NULL) {
2783 jvmti_thread_state()->oops_do(f);
2784 }
2785 }
2786
2787 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2788 Thread::nmethods_do(cf); // (super method is a no-op)
2789
2790 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2791 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2792
2793 if (has_last_Java_frame()) {
2794 // Traverse the execution stack
2795 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2796 fst.current()->nmethods_do(cf);
2797 }
2798 }
2799 }
2800
2801 void JavaThread::metadata_do(void f(Metadata*)) {
2802 Thread::metadata_do(f);
2803 if (has_last_Java_frame()) {
2804 // Traverse the execution stack to call f() on the methods in the stack
2805 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2806 fst.current()->metadata_do(f);
2807 }
2808 } else if (is_Compiler_thread()) {
2809 // need to walk ciMetadata in current compile tasks to keep alive.
2810 CompilerThread* ct = (CompilerThread*)this;
2811 if (ct->env() != NULL) {
2812 ct->env()->metadata_do(f);
2813 }
2814 }
2815 }
2816
2817 // Printing
2818 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2819 switch (_thread_state) {
2820 case _thread_uninitialized: return "_thread_uninitialized";
2821 case _thread_new: return "_thread_new";
2822 case _thread_new_trans: return "_thread_new_trans";
2823 case _thread_in_native: return "_thread_in_native";
2824 case _thread_in_native_trans: return "_thread_in_native_trans";
2825 case _thread_in_vm: return "_thread_in_vm";
2826 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2827 case _thread_in_Java: return "_thread_in_Java";
2828 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2829 case _thread_blocked: return "_thread_blocked";
2830 case _thread_blocked_trans: return "_thread_blocked_trans";
2831 default: return "unknown thread state";
2832 }
2833 }
2834
2835 #ifndef PRODUCT
2836 void JavaThread::print_thread_state_on(outputStream *st) const {
2837 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2838 };
2839 void JavaThread::print_thread_state() const {
2840 print_thread_state_on(tty);
2841 };
2842 #endif // PRODUCT
2843
2844 // Called by Threads::print() for VM_PrintThreads operation
2845 void JavaThread::print_on(outputStream *st) const {
2846 st->print("\"%s\" ", get_thread_name());
2847 oop thread_oop = threadObj();
2848 if (thread_oop != NULL) {
2849 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2850 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2851 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2852 }
2853 Thread::print_on(st);
2854 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2855 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2856 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2857 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2858 }
2859 #ifndef PRODUCT
2860 print_thread_state_on(st);
2861 _safepoint_state->print_on(st);
2862 #endif // PRODUCT
2863 }
2864
2865 // Called by fatal error handler. The difference between this and
2866 // JavaThread::print() is that we can't grab lock or allocate memory.
2867 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2868 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2869 oop thread_obj = threadObj();
2870 if (thread_obj != NULL) {
2871 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2872 }
2873 st->print(" [");
2874 st->print("%s", _get_thread_state_name(_thread_state));
2875 if (osthread()) {
2876 st->print(", id=%d", osthread()->thread_id());
2877 }
2878 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2879 _stack_base - _stack_size, _stack_base);
2880 st->print("]");
2881 return;
2882 }
2883
2884 // Verification
2885
2886 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2887
2888 void JavaThread::verify() {
2889 // Verify oops in the thread.
2890 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2891
2892 // Verify the stack frames.
2893 frames_do(frame_verify);
2894 }
2895
2896 // CR 6300358 (sub-CR 2137150)
2897 // Most callers of this method assume that it can't return NULL but a
2898 // thread may not have a name whilst it is in the process of attaching to
2899 // the VM - see CR 6412693, and there are places where a JavaThread can be
2900 // seen prior to having it's threadObj set (eg JNI attaching threads and
2901 // if vm exit occurs during initialization). These cases can all be accounted
2902 // for such that this method never returns NULL.
2903 const char* JavaThread::get_thread_name() const {
2904 #ifdef ASSERT
2905 // early safepoints can hit while current thread does not yet have TLS
2906 if (!SafepointSynchronize::is_at_safepoint()) {
2907 Thread *cur = Thread::current();
2908 if (!(cur->is_Java_thread() && cur == this)) {
2909 // Current JavaThreads are allowed to get their own name without
2910 // the Threads_lock.
2911 assert_locked_or_safepoint(Threads_lock);
2912 }
2913 }
2914 #endif // ASSERT
2915 return get_thread_name_string();
2916 }
2917
2918 // Returns a non-NULL representation of this thread's name, or a suitable
2919 // descriptive string if there is no set name
2920 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2921 const char* name_str;
2922 oop thread_obj = threadObj();
2923 if (thread_obj != NULL) {
2924 typeArrayOop name = java_lang_Thread::name(thread_obj);
2925 if (name != NULL) {
2926 if (buf == NULL) {
2927 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2928 }
2929 else {
2930 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2931 }
2932 }
2933 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2934 name_str = "<no-name - thread is attaching>";
2935 }
2936 else {
2937 name_str = Thread::name();
2938 }
2939 }
2940 else {
2941 name_str = Thread::name();
2942 }
2943 assert(name_str != NULL, "unexpected NULL thread name");
2944 return name_str;
2945 }
2946
2947
2948 const char* JavaThread::get_threadgroup_name() const {
2949 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2950 oop thread_obj = threadObj();
2951 if (thread_obj != NULL) {
2952 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2953 if (thread_group != NULL) {
2954 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2955 // ThreadGroup.name can be null
2956 if (name != NULL) {
2957 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2958 return str;
2959 }
2960 }
2961 }
2962 return NULL;
2963 }
2964
2965 const char* JavaThread::get_parent_name() const {
2966 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2967 oop thread_obj = threadObj();
2968 if (thread_obj != NULL) {
2969 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2970 if (thread_group != NULL) {
2971 oop parent = java_lang_ThreadGroup::parent(thread_group);
2972 if (parent != NULL) {
2973 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2974 // ThreadGroup.name can be null
2975 if (name != NULL) {
2976 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2977 return str;
2978 }
2979 }
2980 }
2981 }
2982 return NULL;
2983 }
2984
2985 ThreadPriority JavaThread::java_priority() const {
2986 oop thr_oop = threadObj();
2987 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2988 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2989 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2990 return priority;
2991 }
2992
2993 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2994
2995 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2996 // Link Java Thread object <-> C++ Thread
2997
2998 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2999 // and put it into a new Handle. The Handle "thread_oop" can then
3000 // be used to pass the C++ thread object to other methods.
3001
3002 // Set the Java level thread object (jthread) field of the
3003 // new thread (a JavaThread *) to C++ thread object using the
3004 // "thread_oop" handle.
3005
3006 // Set the thread field (a JavaThread *) of the
3007 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3008
3009 Handle thread_oop(Thread::current(),
3010 JNIHandles::resolve_non_null(jni_thread));
3011 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3012 "must be initialized");
3013 set_threadObj(thread_oop());
3014 java_lang_Thread::set_thread(thread_oop(), this);
3015
3016 if (prio == NoPriority) {
3017 prio = java_lang_Thread::priority(thread_oop());
3018 assert(prio != NoPriority, "A valid priority should be present");
3019 }
3020
3021 // Push the Java priority down to the native thread; needs Threads_lock
3022 Thread::set_priority(this, prio);
3023
3024 prepare_ext();
3025
3026 // Add the new thread to the Threads list and set it in motion.
3027 // We must have threads lock in order to call Threads::add.
3028 // It is crucial that we do not block before the thread is
3029 // added to the Threads list for if a GC happens, then the java_thread oop
3030 // will not be visited by GC.
3031 Threads::add(this);
3032 }
3033
3034 oop JavaThread::current_park_blocker() {
3035 // Support for JSR-166 locks
3036 oop thread_oop = threadObj();
3037 if (thread_oop != NULL &&
3038 JDK_Version::current().supports_thread_park_blocker()) {
3039 return java_lang_Thread::park_blocker(thread_oop);
3040 }
3041 return NULL;
3042 }
3043
3044
3045 void JavaThread::print_stack_on(outputStream* st) {
3046 if (!has_last_Java_frame()) return;
3047 ResourceMark rm;
3048 HandleMark hm;
3049
3050 RegisterMap reg_map(this);
3051 vframe* start_vf = last_java_vframe(®_map);
3052 int count = 0;
3053 for (vframe* f = start_vf; f; f = f->sender() ) {
3054 if (f->is_java_frame()) {
3055 javaVFrame* jvf = javaVFrame::cast(f);
3056 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3057
3058 // Print out lock information
3059 if (JavaMonitorsInStackTrace) {
3060 jvf->print_lock_info_on(st, count);
3061 }
3062 } else {
3063 // Ignore non-Java frames
3064 }
3065
3066 // Bail-out case for too deep stacks
3067 count++;
3068 if (MaxJavaStackTraceDepth == count) return;
3069 }
3070 }
3071
3072
3073 // JVMTI PopFrame support
3074 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3075 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3076 if (in_bytes(size_in_bytes) != 0) {
3077 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3078 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3079 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3080 }
3081 }
3082
3083 void* JavaThread::popframe_preserved_args() {
3084 return _popframe_preserved_args;
3085 }
3086
3087 ByteSize JavaThread::popframe_preserved_args_size() {
3088 return in_ByteSize(_popframe_preserved_args_size);
3089 }
3090
3091 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3092 int sz = in_bytes(popframe_preserved_args_size());
3093 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3094 return in_WordSize(sz / wordSize);
3095 }
3096
3097 void JavaThread::popframe_free_preserved_args() {
3098 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3099 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3100 _popframe_preserved_args = NULL;
3101 _popframe_preserved_args_size = 0;
3102 }
3103
3104 #ifndef PRODUCT
3105
3106 void JavaThread::trace_frames() {
3107 tty->print_cr("[Describe stack]");
3108 int frame_no = 1;
3109 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3110 tty->print(" %d. ", frame_no++);
3111 fst.current()->print_value_on(tty,this);
3112 tty->cr();
3113 }
3114 }
3115
3116 class PrintAndVerifyOopClosure: public OopClosure {
3117 protected:
3118 template <class T> inline void do_oop_work(T* p) {
3119 oop obj = oopDesc::load_decode_heap_oop(p);
3120 if (obj == NULL) return;
3121 tty->print(INTPTR_FORMAT ": ", p);
3122 if (obj->is_oop_or_null()) {
3123 if (obj->is_objArray()) {
3124 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3125 } else {
3126 obj->print();
3127 }
3128 } else {
3129 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3130 }
3131 tty->cr();
3132 }
3133 public:
3134 virtual void do_oop(oop* p) { do_oop_work(p); }
3135 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3136 };
3137
3138
3139 static void oops_print(frame* f, const RegisterMap *map) {
3140 PrintAndVerifyOopClosure print;
3141 f->print_value();
3142 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3143 }
3144
3145 // Print our all the locations that contain oops and whether they are
3146 // valid or not. This useful when trying to find the oldest frame
3147 // where an oop has gone bad since the frame walk is from youngest to
3148 // oldest.
3149 void JavaThread::trace_oops() {
3150 tty->print_cr("[Trace oops]");
3151 frames_do(oops_print);
3152 }
3153
3154
3155 #ifdef ASSERT
3156 // Print or validate the layout of stack frames
3157 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3158 ResourceMark rm;
3159 PRESERVE_EXCEPTION_MARK;
3160 FrameValues values;
3161 int frame_no = 0;
3162 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3163 fst.current()->describe(values, ++frame_no);
3164 if (depth == frame_no) break;
3165 }
3166 if (validate_only) {
3167 values.validate();
3168 } else {
3169 tty->print_cr("[Describe stack layout]");
3170 values.print(this);
3171 }
3172 }
3173 #endif
3174
3175 void JavaThread::trace_stack_from(vframe* start_vf) {
3176 ResourceMark rm;
3177 int vframe_no = 1;
3178 for (vframe* f = start_vf; f; f = f->sender() ) {
3179 if (f->is_java_frame()) {
3180 javaVFrame::cast(f)->print_activation(vframe_no++);
3181 } else {
3182 f->print();
3183 }
3184 if (vframe_no > StackPrintLimit) {
3185 tty->print_cr("...<more frames>...");
3186 return;
3187 }
3188 }
3189 }
3190
3191
3192 void JavaThread::trace_stack() {
3193 if (!has_last_Java_frame()) return;
3194 ResourceMark rm;
3195 HandleMark hm;
3196 RegisterMap reg_map(this);
3197 trace_stack_from(last_java_vframe(®_map));
3198 }
3199
3200
3201 #endif // PRODUCT
3202
3203
3204 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3205 assert(reg_map != NULL, "a map must be given");
3206 frame f = last_frame();
3207 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3208 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3209 }
3210 return NULL;
3211 }
3212
3213
3214 Klass* JavaThread::security_get_caller_class(int depth) {
3215 vframeStream vfst(this);
3216 vfst.security_get_caller_frame(depth);
3217 if (!vfst.at_end()) {
3218 return vfst.method()->method_holder();
3219 }
3220 return NULL;
3221 }
3222
3223 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3224 assert(thread->is_Compiler_thread(), "must be compiler thread");
3225 CompileBroker::compiler_thread_loop();
3226 }
3227
3228 // Create a CompilerThread
3229 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3230 : JavaThread(&compiler_thread_entry) {
3231 _env = NULL;
3232 _log = NULL;
3233 _task = NULL;
3234 _queue = queue;
3235 _counters = counters;
3236 _buffer_blob = NULL;
3237 _scanned_nmethod = NULL;
3238 _compiler = NULL;
3239
3240 #ifndef PRODUCT
3241 _ideal_graph_printer = NULL;
3242 #endif
3243 }
3244
3245 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3246 JavaThread::oops_do(f, cld_f, cf);
3247 if (_scanned_nmethod != NULL && cf != NULL) {
3248 // Safepoints can occur when the sweeper is scanning an nmethod so
3249 // process it here to make sure it isn't unloaded in the middle of
3250 // a scan.
3251 cf->do_code_blob(_scanned_nmethod);
3252 }
3253 }
3254
3255
3256 // ======= Threads ========
3257
3258 // The Threads class links together all active threads, and provides
3259 // operations over all threads. It is protected by its own Mutex
3260 // lock, which is also used in other contexts to protect thread
3261 // operations from having the thread being operated on from exiting
3262 // and going away unexpectedly (e.g., safepoint synchronization)
3263
3264 JavaThread* Threads::_thread_list = NULL;
3265 int Threads::_number_of_threads = 0;
3266 int Threads::_number_of_non_daemon_threads = 0;
3267 int Threads::_return_code = 0;
3268 size_t JavaThread::_stack_size_at_create = 0;
3269 #ifdef ASSERT
3270 bool Threads::_vm_complete = false;
3271 #endif
3272
3273 // All JavaThreads
3274 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3275
3276 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3277 void Threads::threads_do(ThreadClosure* tc) {
3278 assert_locked_or_safepoint(Threads_lock);
3279 // ALL_JAVA_THREADS iterates through all JavaThreads
3280 ALL_JAVA_THREADS(p) {
3281 tc->do_thread(p);
3282 }
3283 // Someday we could have a table or list of all non-JavaThreads.
3284 // For now, just manually iterate through them.
3285 tc->do_thread(VMThread::vm_thread());
3286 Universe::heap()->gc_threads_do(tc);
3287 WatcherThread *wt = WatcherThread::watcher_thread();
3288 // Strictly speaking, the following NULL check isn't sufficient to make sure
3289 // the data for WatcherThread is still valid upon being examined. However,
3290 // considering that WatchThread terminates when the VM is on the way to
3291 // exit at safepoint, the chance of the above is extremely small. The right
3292 // way to prevent termination of WatcherThread would be to acquire
3293 // Terminator_lock, but we can't do that without violating the lock rank
3294 // checking in some cases.
3295 if (wt != NULL)
3296 tc->do_thread(wt);
3297
3298 // If CompilerThreads ever become non-JavaThreads, add them here
3299 }
3300
3301 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3302
3303 extern void JDK_Version_init();
3304
3305 // Check version
3306 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3307
3308 // Initialize the output stream module
3309 ostream_init();
3310
3311 // Process java launcher properties.
3312 Arguments::process_sun_java_launcher_properties(args);
3313
3314 // Initialize the os module before using TLS
3315 os::init();
3316
3317 // Initialize system properties.
3318 Arguments::init_system_properties();
3319
3320 // So that JDK version can be used as a discrimintor when parsing arguments
3321 JDK_Version_init();
3322
3323 // Update/Initialize System properties after JDK version number is known
3324 Arguments::init_version_specific_system_properties();
3325
3326 // Parse arguments
3327 jint parse_result = Arguments::parse(args);
3328 if (parse_result != JNI_OK) return parse_result;
3329
3330 os::init_before_ergo();
3331
3332 jint ergo_result = Arguments::apply_ergo();
3333 if (ergo_result != JNI_OK) return ergo_result;
3334
3335 if (PauseAtStartup) {
3336 os::pause();
3337 }
3338
3339 #ifndef USDT2
3340 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3341 #else /* USDT2 */
3342 HOTSPOT_VM_INIT_BEGIN();
3343 #endif /* USDT2 */
3344
3345 // Record VM creation timing statistics
3346 TraceVmCreationTime create_vm_timer;
3347 create_vm_timer.start();
3348
3349 // Timing (must come after argument parsing)
3350 TraceTime timer("Create VM", TraceStartupTime);
3351
3352 // Initialize the os module after parsing the args
3353 jint os_init_2_result = os::init_2();
3354 if (os_init_2_result != JNI_OK) return os_init_2_result;
3355
3356 jint adjust_after_os_result = Arguments::adjust_after_os();
3357 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3358
3359 // intialize TLS
3360 ThreadLocalStorage::init();
3361
3362 // Initialize output stream logging
3363 ostream_init_log();
3364
3365 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3366 // Must be before create_vm_init_agents()
3367 if (Arguments::init_libraries_at_startup()) {
3368 convert_vm_init_libraries_to_agents();
3369 }
3370
3371 // Launch -agentlib/-agentpath and converted -Xrun agents
3372 if (Arguments::init_agents_at_startup()) {
3373 create_vm_init_agents();
3374 }
3375
3376 // Initialize Threads state
3377 _thread_list = NULL;
3378 _number_of_threads = 0;
3379 _number_of_non_daemon_threads = 0;
3380
3381 // Initialize global data structures and create system classes in heap
3382 vm_init_globals();
3383
3384 // Attach the main thread to this os thread
3385 JavaThread* main_thread = new JavaThread();
3386 main_thread->set_thread_state(_thread_in_vm);
3387 // must do this before set_active_handles and initialize_thread_local_storage
3388 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3389 // change the stack size recorded here to one based on the java thread
3390 // stacksize. This adjusted size is what is used to figure the placement
3391 // of the guard pages.
3392 main_thread->record_stack_base_and_size();
3393 main_thread->initialize_thread_local_storage();
3394
3395 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3396
3397 if (!main_thread->set_as_starting_thread()) {
3398 vm_shutdown_during_initialization(
3399 "Failed necessary internal allocation. Out of swap space");
3400 delete main_thread;
3401 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3402 return JNI_ENOMEM;
3403 }
3404
3405 // Enable guard page *after* os::create_main_thread(), otherwise it would
3406 // crash Linux VM, see notes in os_linux.cpp.
3407 main_thread->create_stack_guard_pages();
3408
3409 // Initialize Java-Level synchronization subsystem
3410 ObjectMonitor::Initialize() ;
3411
3412 // Initialize global modules
3413 jint status = init_globals();
3414 if (status != JNI_OK) {
3415 delete main_thread;
3416 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3417 return status;
3418 }
3419
3420 // Should be done after the heap is fully created
3421 main_thread->cache_global_variables();
3422
3423 HandleMark hm;
3424
3425 { MutexLocker mu(Threads_lock);
3426 Threads::add(main_thread);
3427 }
3428
3429 // Any JVMTI raw monitors entered in onload will transition into
3430 // real raw monitor. VM is setup enough here for raw monitor enter.
3431 JvmtiExport::transition_pending_onload_raw_monitors();
3432
3433 // Create the VMThread
3434 { TraceTime timer("Start VMThread", TraceStartupTime);
3435 VMThread::create();
3436 Thread* vmthread = VMThread::vm_thread();
3437
3438 if (!os::create_thread(vmthread, os::vm_thread))
3439 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3440
3441 // Wait for the VM thread to become ready, and VMThread::run to initialize
3442 // Monitors can have spurious returns, must always check another state flag
3443 {
3444 MutexLocker ml(Notify_lock);
3445 os::start_thread(vmthread);
3446 while (vmthread->active_handles() == NULL) {
3447 Notify_lock->wait();
3448 }
3449 }
3450 }
3451
3452 assert (Universe::is_fully_initialized(), "not initialized");
3453 if (VerifyDuringStartup) {
3454 // Make sure we're starting with a clean slate.
3455 VM_Verify verify_op;
3456 VMThread::execute(&verify_op);
3457 }
3458
3459 EXCEPTION_MARK;
3460
3461 // At this point, the Universe is initialized, but we have not executed
3462 // any byte code. Now is a good time (the only time) to dump out the
3463 // internal state of the JVM for sharing.
3464 if (DumpSharedSpaces) {
3465 MetaspaceShared::preload_and_dump(CHECK_0);
3466 ShouldNotReachHere();
3467 }
3468
3469 // Always call even when there are not JVMTI environments yet, since environments
3470 // may be attached late and JVMTI must track phases of VM execution
3471 JvmtiExport::enter_start_phase();
3472
3473 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3474 JvmtiExport::post_vm_start();
3475
3476 {
3477 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3478
3479 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3480 create_vm_init_libraries();
3481 }
3482
3483 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3484
3485 // Initialize java_lang.System (needed before creating the thread)
3486 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3487 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3488 Handle thread_group = create_initial_thread_group(CHECK_0);
3489 Universe::set_main_thread_group(thread_group());
3490 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3491 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3492 main_thread->set_threadObj(thread_object);
3493 // Set thread status to running since main thread has
3494 // been started and running.
3495 java_lang_Thread::set_thread_status(thread_object,
3496 java_lang_Thread::RUNNABLE);
3497
3498 // The VM creates & returns objects of this class. Make sure it's initialized.
3499 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3500
3501 // The VM preresolves methods to these classes. Make sure that they get initialized
3502 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3503 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3504 call_initializeSystemClass(CHECK_0);
3505
3506 // get the Java runtime name after java.lang.System is initialized
3507 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3508 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3509
3510 // an instance of OutOfMemory exception has been allocated earlier
3511 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3512 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3513 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3514 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3515 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3516 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3517 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3518 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3519 }
3520
3521 // See : bugid 4211085.
3522 // Background : the static initializer of java.lang.Compiler tries to read
3523 // property"java.compiler" and read & write property "java.vm.info".
3524 // When a security manager is installed through the command line
3525 // option "-Djava.security.manager", the above properties are not
3526 // readable and the static initializer for java.lang.Compiler fails
3527 // resulting in a NoClassDefFoundError. This can happen in any
3528 // user code which calls methods in java.lang.Compiler.
3529 // Hack : the hack is to pre-load and initialize this class, so that only
3530 // system domains are on the stack when the properties are read.
3531 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3532 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3533 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3534 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3535 // Once that is done, we should remove this hack.
3536 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3537
3538 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3539 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3540 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3541 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3542 // This should also be taken out as soon as 4211383 gets fixed.
3543 reset_vm_info_property(CHECK_0);
3544
3545 quicken_jni_functions();
3546
3547 // Must be run after init_ft which initializes ft_enabled
3548 if (TRACE_INITIALIZE() != JNI_OK) {
3549 vm_exit_during_initialization("Failed to initialize tracing backend");
3550 }
3551
3552 // Set flag that basic initialization has completed. Used by exceptions and various
3553 // debug stuff, that does not work until all basic classes have been initialized.
3554 set_init_completed();
3555
3556 Metaspace::post_initialize();
3557
3558 #ifndef USDT2
3559 HS_DTRACE_PROBE(hotspot, vm__init__end);
3560 #else /* USDT2 */
3561 HOTSPOT_VM_INIT_END();
3562 #endif /* USDT2 */
3563
3564 // record VM initialization completion time
3565 #if INCLUDE_MANAGEMENT
3566 Management::record_vm_init_completed();
3567 #endif // INCLUDE_MANAGEMENT
3568
3569 // Compute system loader. Note that this has to occur after set_init_completed, since
3570 // valid exceptions may be thrown in the process.
3571 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3572 // set_init_completed has just been called, causing exceptions not to be shortcut
3573 // anymore. We call vm_exit_during_initialization directly instead.
3574 SystemDictionary::compute_java_system_loader(THREAD);
3575 if (HAS_PENDING_EXCEPTION) {
3576 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3577 }
3578
3579 #if INCLUDE_ALL_GCS
3580 // Support for ConcurrentMarkSweep. This should be cleaned up
3581 // and better encapsulated. The ugly nested if test would go away
3582 // once things are properly refactored. XXX YSR
3583 if (UseConcMarkSweepGC || UseG1GC) {
3584 if (UseConcMarkSweepGC) {
3585 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3586 } else {
3587 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3588 }
3589 if (HAS_PENDING_EXCEPTION) {
3590 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3591 }
3592 }
3593 #endif // INCLUDE_ALL_GCS
3594
3595 // Always call even when there are not JVMTI environments yet, since environments
3596 // may be attached late and JVMTI must track phases of VM execution
3597 JvmtiExport::enter_live_phase();
3598
3599 // Signal Dispatcher needs to be started before VMInit event is posted
3600 os::signal_init();
3601
3602 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3603 if (!DisableAttachMechanism) {
3604 AttachListener::vm_start();
3605 if (StartAttachListener || AttachListener::init_at_startup()) {
3606 AttachListener::init();
3607 }
3608 }
3609
3610 // Launch -Xrun agents
3611 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3612 // back-end can launch with -Xdebug -Xrunjdwp.
3613 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3614 create_vm_init_libraries();
3615 }
3616
3617 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3618 JvmtiExport::post_vm_initialized();
3619
3620 if (TRACE_START() != JNI_OK) {
3621 vm_exit_during_initialization("Failed to start tracing backend.");
3622 }
3623
3624 if (CleanChunkPoolAsync) {
3625 Chunk::start_chunk_pool_cleaner_task();
3626 }
3627
3628 // initialize compiler(s)
3629 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3630 CompileBroker::compilation_init();
3631 #endif
3632
3633 if (EnableInvokeDynamic) {
3634 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3635 // It is done after compilers are initialized, because otherwise compilations of
3636 // signature polymorphic MH intrinsics can be missed
3637 // (see SystemDictionary::find_method_handle_intrinsic).
3638 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3639 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3640 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3641 }
3642
3643 #if INCLUDE_MANAGEMENT
3644 Management::initialize(THREAD);
3645 #endif // INCLUDE_MANAGEMENT
3646
3647 if (HAS_PENDING_EXCEPTION) {
3648 // management agent fails to start possibly due to
3649 // configuration problem and is responsible for printing
3650 // stack trace if appropriate. Simply exit VM.
3651 vm_exit(1);
3652 }
3653
3654 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3655 if (MemProfiling) MemProfiler::engage();
3656 StatSampler::engage();
3657 if (CheckJNICalls) JniPeriodicChecker::engage();
3658
3659 BiasedLocking::init();
3660
3661 #if INCLUDE_RTM_OPT
3662 RTMLockingCounters::init();
3663 #endif
3664
3665 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3666 call_postVMInitHook(THREAD);
3667 // The Java side of PostVMInitHook.run must deal with all
3668 // exceptions and provide means of diagnosis.
3669 if (HAS_PENDING_EXCEPTION) {
3670 CLEAR_PENDING_EXCEPTION;
3671 }
3672 }
3673
3674 {
3675 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3676 // Make sure the watcher thread can be started by WatcherThread::start()
3677 // or by dynamic enrollment.
3678 WatcherThread::make_startable();
3679 // Start up the WatcherThread if there are any periodic tasks
3680 // NOTE: All PeriodicTasks should be registered by now. If they
3681 // aren't, late joiners might appear to start slowly (we might
3682 // take a while to process their first tick).
3683 if (PeriodicTask::num_tasks() > 0) {
3684 WatcherThread::start();
3685 }
3686 }
3687
3688 // Give os specific code one last chance to start
3689 os::init_3();
3690
3691 create_vm_timer.end();
3692 #ifdef ASSERT
3693 _vm_complete = true;
3694 #endif
3695 return JNI_OK;
3696 }
3697
3698 // type for the Agent_OnLoad and JVM_OnLoad entry points
3699 extern "C" {
3700 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3701 }
3702 // Find a command line agent library and return its entry point for
3703 // -agentlib: -agentpath: -Xrun
3704 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3705 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3706 OnLoadEntry_t on_load_entry = NULL;
3707 void *library = NULL;
3708
3709 if (!agent->valid()) {
3710 char buffer[JVM_MAXPATHLEN];
3711 char ebuf[1024];
3712 const char *name = agent->name();
3713 const char *msg = "Could not find agent library ";
3714
3715 // First check to see if agent is statically linked into executable
3716 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3717 library = agent->os_lib();
3718 } else if (agent->is_absolute_path()) {
3719 library = os::dll_load(name, ebuf, sizeof ebuf);
3720 if (library == NULL) {
3721 const char *sub_msg = " in absolute path, with error: ";
3722 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3723 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3724 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3725 // If we can't find the agent, exit.
3726 vm_exit_during_initialization(buf, NULL);
3727 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3728 }
3729 } else {
3730 // Try to load the agent from the standard dll directory
3731 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3732 name)) {
3733 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3734 }
3735 if (library == NULL) { // Try the local directory
3736 char ns[1] = {0};
3737 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3738 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3739 }
3740 if (library == NULL) {
3741 const char *sub_msg = " on the library path, with error: ";
3742 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3743 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3744 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3745 // If we can't find the agent, exit.
3746 vm_exit_during_initialization(buf, NULL);
3747 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3748 }
3749 }
3750 }
3751 agent->set_os_lib(library);
3752 agent->set_valid();
3753 }
3754
3755 // Find the OnLoad function.
3756 on_load_entry =
3757 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3758 false,
3759 on_load_symbols,
3760 num_symbol_entries));
3761 return on_load_entry;
3762 }
3763
3764 // Find the JVM_OnLoad entry point
3765 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3766 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3767 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3768 }
3769
3770 // Find the Agent_OnLoad entry point
3771 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3772 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3773 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3774 }
3775
3776 // For backwards compatibility with -Xrun
3777 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3778 // treated like -agentpath:
3779 // Must be called before agent libraries are created
3780 void Threads::convert_vm_init_libraries_to_agents() {
3781 AgentLibrary* agent;
3782 AgentLibrary* next;
3783
3784 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3785 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3786 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3787
3788 // If there is an JVM_OnLoad function it will get called later,
3789 // otherwise see if there is an Agent_OnLoad
3790 if (on_load_entry == NULL) {
3791 on_load_entry = lookup_agent_on_load(agent);
3792 if (on_load_entry != NULL) {
3793 // switch it to the agent list -- so that Agent_OnLoad will be called,
3794 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3795 Arguments::convert_library_to_agent(agent);
3796 } else {
3797 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3798 }
3799 }
3800 }
3801 }
3802
3803 // Create agents for -agentlib: -agentpath: and converted -Xrun
3804 // Invokes Agent_OnLoad
3805 // Called very early -- before JavaThreads exist
3806 void Threads::create_vm_init_agents() {
3807 extern struct JavaVM_ main_vm;
3808 AgentLibrary* agent;
3809
3810 JvmtiExport::enter_onload_phase();
3811
3812 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3813 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3814
3815 if (on_load_entry != NULL) {
3816 // Invoke the Agent_OnLoad function
3817 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3818 if (err != JNI_OK) {
3819 vm_exit_during_initialization("agent library failed to init", agent->name());
3820 }
3821 } else {
3822 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3823 }
3824 }
3825 JvmtiExport::enter_primordial_phase();
3826 }
3827
3828 extern "C" {
3829 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3830 }
3831
3832 void Threads::shutdown_vm_agents() {
3833 // Send any Agent_OnUnload notifications
3834 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3835 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3836 extern struct JavaVM_ main_vm;
3837 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3838
3839 // Find the Agent_OnUnload function.
3840 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3841 os::find_agent_function(agent,
3842 false,
3843 on_unload_symbols,
3844 num_symbol_entries));
3845
3846 // Invoke the Agent_OnUnload function
3847 if (unload_entry != NULL) {
3848 JavaThread* thread = JavaThread::current();
3849 ThreadToNativeFromVM ttn(thread);
3850 HandleMark hm(thread);
3851 (*unload_entry)(&main_vm);
3852 }
3853 }
3854 }
3855
3856 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3857 // Invokes JVM_OnLoad
3858 void Threads::create_vm_init_libraries() {
3859 extern struct JavaVM_ main_vm;
3860 AgentLibrary* agent;
3861
3862 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3863 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3864
3865 if (on_load_entry != NULL) {
3866 // Invoke the JVM_OnLoad function
3867 JavaThread* thread = JavaThread::current();
3868 ThreadToNativeFromVM ttn(thread);
3869 HandleMark hm(thread);
3870 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3871 if (err != JNI_OK) {
3872 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3873 }
3874 } else {
3875 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3876 }
3877 }
3878 }
3879
3880 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3881 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3882
3883 JavaThread* java_thread = NULL;
3884 // Sequential search for now. Need to do better optimization later.
3885 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3886 oop tobj = thread->threadObj();
3887 if (!thread->is_exiting() &&
3888 tobj != NULL &&
3889 java_tid == java_lang_Thread::thread_id(tobj)) {
3890 java_thread = thread;
3891 break;
3892 }
3893 }
3894 return java_thread;
3895 }
3896
3897
3898 // Last thread running calls java.lang.Shutdown.shutdown()
3899 void JavaThread::invoke_shutdown_hooks() {
3900 HandleMark hm(this);
3901
3902 // We could get here with a pending exception, if so clear it now.
3903 if (this->has_pending_exception()) {
3904 this->clear_pending_exception();
3905 }
3906
3907 EXCEPTION_MARK;
3908 Klass* k =
3909 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3910 THREAD);
3911 if (k != NULL) {
3912 // SystemDictionary::resolve_or_null will return null if there was
3913 // an exception. If we cannot load the Shutdown class, just don't
3914 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3915 // and finalizers (if runFinalizersOnExit is set) won't be run.
3916 // Note that if a shutdown hook was registered or runFinalizersOnExit
3917 // was called, the Shutdown class would have already been loaded
3918 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3919 instanceKlassHandle shutdown_klass (THREAD, k);
3920 JavaValue result(T_VOID);
3921 JavaCalls::call_static(&result,
3922 shutdown_klass,
3923 vmSymbols::shutdown_method_name(),
3924 vmSymbols::void_method_signature(),
3925 THREAD);
3926 }
3927 CLEAR_PENDING_EXCEPTION;
3928 }
3929
3930 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3931 // the program falls off the end of main(). Another VM exit path is through
3932 // vm_exit() when the program calls System.exit() to return a value or when
3933 // there is a serious error in VM. The two shutdown paths are not exactly
3934 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3935 // and VM_Exit op at VM level.
3936 //
3937 // Shutdown sequence:
3938 // + Shutdown native memory tracking if it is on
3939 // + Wait until we are the last non-daemon thread to execute
3940 // <-- every thing is still working at this moment -->
3941 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3942 // shutdown hooks, run finalizers if finalization-on-exit
3943 // + Call before_exit(), prepare for VM exit
3944 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3945 // currently the only user of this mechanism is File.deleteOnExit())
3946 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3947 // post thread end and vm death events to JVMTI,
3948 // stop signal thread
3949 // + Call JavaThread::exit(), it will:
3950 // > release JNI handle blocks, remove stack guard pages
3951 // > remove this thread from Threads list
3952 // <-- no more Java code from this thread after this point -->
3953 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3954 // the compiler threads at safepoint
3955 // <-- do not use anything that could get blocked by Safepoint -->
3956 // + Disable tracing at JNI/JVM barriers
3957 // + Set _vm_exited flag for threads that are still running native code
3958 // + Delete this thread
3959 // + Call exit_globals()
3960 // > deletes tty
3961 // > deletes PerfMemory resources
3962 // + Return to caller
3963
3964 bool Threads::destroy_vm() {
3965 JavaThread* thread = JavaThread::current();
3966
3967 #ifdef ASSERT
3968 _vm_complete = false;
3969 #endif
3970 // Wait until we are the last non-daemon thread to execute
3971 { MutexLocker nu(Threads_lock);
3972 while (Threads::number_of_non_daemon_threads() > 1 )
3973 // This wait should make safepoint checks, wait without a timeout,
3974 // and wait as a suspend-equivalent condition.
3975 //
3976 // Note: If the FlatProfiler is running and this thread is waiting
3977 // for another non-daemon thread to finish, then the FlatProfiler
3978 // is waiting for the external suspend request on this thread to
3979 // complete. wait_for_ext_suspend_completion() will eventually
3980 // timeout, but that takes time. Making this wait a suspend-
3981 // equivalent condition solves that timeout problem.
3982 //
3983 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3984 Mutex::_as_suspend_equivalent_flag);
3985 }
3986
3987 // Hang forever on exit if we are reporting an error.
3988 if (ShowMessageBoxOnError && is_error_reported()) {
3989 os::infinite_sleep();
3990 }
3991 os::wait_for_keypress_at_exit();
3992
3993 if (JDK_Version::is_jdk12x_version()) {
3994 // We are the last thread running, so check if finalizers should be run.
3995 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3996 HandleMark rm(thread);
3997 Universe::run_finalizers_on_exit();
3998 } else {
3999 // run Java level shutdown hooks
4000 thread->invoke_shutdown_hooks();
4001 }
4002
4003 before_exit(thread);
4004
4005 thread->exit(true);
4006
4007 // Stop VM thread.
4008 {
4009 // 4945125 The vm thread comes to a safepoint during exit.
4010 // GC vm_operations can get caught at the safepoint, and the
4011 // heap is unparseable if they are caught. Grab the Heap_lock
4012 // to prevent this. The GC vm_operations will not be able to
4013 // queue until after the vm thread is dead. After this point,
4014 // we'll never emerge out of the safepoint before the VM exits.
4015
4016 MutexLocker ml(Heap_lock);
4017
4018 VMThread::wait_for_vm_thread_exit();
4019 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4020 VMThread::destroy();
4021 }
4022
4023 // clean up ideal graph printers
4024 #if defined(COMPILER2) && !defined(PRODUCT)
4025 IdealGraphPrinter::clean_up();
4026 #endif
4027
4028 // Now, all Java threads are gone except daemon threads. Daemon threads
4029 // running Java code or in VM are stopped by the Safepoint. However,
4030 // daemon threads executing native code are still running. But they
4031 // will be stopped at native=>Java/VM barriers. Note that we can't
4032 // simply kill or suspend them, as it is inherently deadlock-prone.
4033
4034 #ifndef PRODUCT
4035 // disable function tracing at JNI/JVM barriers
4036 TraceJNICalls = false;
4037 TraceJVMCalls = false;
4038 TraceRuntimeCalls = false;
4039 #endif
4040
4041 VM_Exit::set_vm_exited();
4042
4043 notify_vm_shutdown();
4044
4045 delete thread;
4046
4047 // exit_globals() will delete tty
4048 exit_globals();
4049
4050 return true;
4051 }
4052
4053
4054 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4055 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4056 return is_supported_jni_version(version);
4057 }
4058
4059
4060 jboolean Threads::is_supported_jni_version(jint version) {
4061 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4062 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4063 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4064 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4065 return JNI_FALSE;
4066 }
4067
4068
4069 void Threads::add(JavaThread* p, bool force_daemon) {
4070 // The threads lock must be owned at this point
4071 assert_locked_or_safepoint(Threads_lock);
4072
4073 // See the comment for this method in thread.hpp for its purpose and
4074 // why it is called here.
4075 p->initialize_queues();
4076 p->set_next(_thread_list);
4077 _thread_list = p;
4078 _number_of_threads++;
4079 oop threadObj = p->threadObj();
4080 bool daemon = true;
4081 // Bootstrapping problem: threadObj can be null for initial
4082 // JavaThread (or for threads attached via JNI)
4083 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4084 _number_of_non_daemon_threads++;
4085 daemon = false;
4086 }
4087
4088 ThreadService::add_thread(p, daemon);
4089
4090 // Possible GC point.
4091 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4092 }
4093
4094 void Threads::remove(JavaThread* p) {
4095 // Extra scope needed for Thread_lock, so we can check
4096 // that we do not remove thread without safepoint code notice
4097 { MutexLocker ml(Threads_lock);
4098
4099 assert(includes(p), "p must be present");
4100
4101 JavaThread* current = _thread_list;
4102 JavaThread* prev = NULL;
4103
4104 while (current != p) {
4105 prev = current;
4106 current = current->next();
4107 }
4108
4109 if (prev) {
4110 prev->set_next(current->next());
4111 } else {
4112 _thread_list = p->next();
4113 }
4114 _number_of_threads--;
4115 oop threadObj = p->threadObj();
4116 bool daemon = true;
4117 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4118 _number_of_non_daemon_threads--;
4119 daemon = false;
4120
4121 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4122 // on destroy_vm will wake up.
4123 if (number_of_non_daemon_threads() == 1)
4124 Threads_lock->notify_all();
4125 }
4126 ThreadService::remove_thread(p, daemon);
4127
4128 // Make sure that safepoint code disregard this thread. This is needed since
4129 // the thread might mess around with locks after this point. This can cause it
4130 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4131 // of this thread since it is removed from the queue.
4132 p->set_terminated_value();
4133 } // unlock Threads_lock
4134
4135 // Since Events::log uses a lock, we grab it outside the Threads_lock
4136 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4137 }
4138
4139 // Threads_lock must be held when this is called (or must be called during a safepoint)
4140 bool Threads::includes(JavaThread* p) {
4141 assert(Threads_lock->is_locked(), "sanity check");
4142 ALL_JAVA_THREADS(q) {
4143 if (q == p ) {
4144 return true;
4145 }
4146 }
4147 return false;
4148 }
4149
4150 // Operations on the Threads list for GC. These are not explicitly locked,
4151 // but the garbage collector must provide a safe context for them to run.
4152 // In particular, these things should never be called when the Threads_lock
4153 // is held by some other thread. (Note: the Safepoint abstraction also
4154 // uses the Threads_lock to gurantee this property. It also makes sure that
4155 // all threads gets blocked when exiting or starting).
4156
4157 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4158 ALL_JAVA_THREADS(p) {
4159 p->oops_do(f, cld_f, cf);
4160 }
4161 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4162 }
4163
4164 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4165 // Introduce a mechanism allowing parallel threads to claim threads as
4166 // root groups. Overhead should be small enough to use all the time,
4167 // even in sequential code.
4168 SharedHeap* sh = SharedHeap::heap();
4169 // Cannot yet substitute active_workers for n_par_threads
4170 // because of G1CollectedHeap::verify() use of
4171 // SharedHeap::process_roots(). n_par_threads == 0 will
4172 // turn off parallelism in process_roots while active_workers
4173 // is being used for parallelism elsewhere.
4174 bool is_par = sh->n_par_threads() > 0;
4175 assert(!is_par ||
4176 (SharedHeap::heap()->n_par_threads() ==
4177 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4178 int cp = SharedHeap::heap()->strong_roots_parity();
4179 ALL_JAVA_THREADS(p) {
4180 if (p->claim_oops_do(is_par, cp)) {
4181 p->oops_do(f, cld_f, cf);
4182 }
4183 }
4184 VMThread* vmt = VMThread::vm_thread();
4185 if (vmt->claim_oops_do(is_par, cp)) {
4186 vmt->oops_do(f, cld_f, cf);
4187 }
4188 }
4189
4190 #if INCLUDE_ALL_GCS
4191 // Used by ParallelScavenge
4192 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4193 ALL_JAVA_THREADS(p) {
4194 q->enqueue(new ThreadRootsTask(p));
4195 }
4196 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4197 }
4198
4199 // Used by Parallel Old
4200 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4201 ALL_JAVA_THREADS(p) {
4202 q->enqueue(new ThreadRootsMarkingTask(p));
4203 }
4204 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4205 }
4206 #endif // INCLUDE_ALL_GCS
4207
4208 void Threads::nmethods_do(CodeBlobClosure* cf) {
4209 ALL_JAVA_THREADS(p) {
4210 p->nmethods_do(cf);
4211 }
4212 VMThread::vm_thread()->nmethods_do(cf);
4213 }
4214
4215 void Threads::metadata_do(void f(Metadata*)) {
4216 ALL_JAVA_THREADS(p) {
4217 p->metadata_do(f);
4218 }
4219 }
4220
4221 void Threads::gc_epilogue() {
4222 ALL_JAVA_THREADS(p) {
4223 p->gc_epilogue();
4224 }
4225 }
4226
4227 void Threads::gc_prologue() {
4228 ALL_JAVA_THREADS(p) {
4229 p->gc_prologue();
4230 }
4231 }
4232
4233 void Threads::deoptimized_wrt_marked_nmethods() {
4234 ALL_JAVA_THREADS(p) {
4235 p->deoptimized_wrt_marked_nmethods();
4236 }
4237 }
4238
4239
4240 // Get count Java threads that are waiting to enter the specified monitor.
4241 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4242 address monitor, bool doLock) {
4243 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4244 "must grab Threads_lock or be at safepoint");
4245 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4246
4247 int i = 0;
4248 {
4249 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4250 ALL_JAVA_THREADS(p) {
4251 if (p->is_Compiler_thread()) continue;
4252
4253 address pending = (address)p->current_pending_monitor();
4254 if (pending == monitor) { // found a match
4255 if (i < count) result->append(p); // save the first count matches
4256 i++;
4257 }
4258 }
4259 }
4260 return result;
4261 }
4262
4263
4264 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4265 assert(doLock ||
4266 Threads_lock->owned_by_self() ||
4267 SafepointSynchronize::is_at_safepoint(),
4268 "must grab Threads_lock or be at safepoint");
4269
4270 // NULL owner means not locked so we can skip the search
4271 if (owner == NULL) return NULL;
4272
4273 {
4274 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4275 ALL_JAVA_THREADS(p) {
4276 // first, see if owner is the address of a Java thread
4277 if (owner == (address)p) return p;
4278 }
4279 }
4280 // Cannot assert on lack of success here since this function may be
4281 // used by code that is trying to report useful problem information
4282 // like deadlock detection.
4283 if (UseHeavyMonitors) return NULL;
4284
4285 //
4286 // If we didn't find a matching Java thread and we didn't force use of
4287 // heavyweight monitors, then the owner is the stack address of the
4288 // Lock Word in the owning Java thread's stack.
4289 //
4290 JavaThread* the_owner = NULL;
4291 {
4292 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4293 ALL_JAVA_THREADS(q) {
4294 if (q->is_lock_owned(owner)) {
4295 the_owner = q;
4296 break;
4297 }
4298 }
4299 }
4300 // cannot assert on lack of success here; see above comment
4301 return the_owner;
4302 }
4303
4304 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4305 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4306 char buf[32];
4307 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4308
4309 st->print_cr("Full thread dump %s (%s %s):",
4310 Abstract_VM_Version::vm_name(),
4311 Abstract_VM_Version::vm_release(),
4312 Abstract_VM_Version::vm_info_string()
4313 );
4314 st->cr();
4315
4316 #if INCLUDE_ALL_GCS
4317 // Dump concurrent locks
4318 ConcurrentLocksDump concurrent_locks;
4319 if (print_concurrent_locks) {
4320 concurrent_locks.dump_at_safepoint();
4321 }
4322 #endif // INCLUDE_ALL_GCS
4323
4324 ALL_JAVA_THREADS(p) {
4325 ResourceMark rm;
4326 p->print_on(st);
4327 if (print_stacks) {
4328 if (internal_format) {
4329 p->trace_stack();
4330 } else {
4331 p->print_stack_on(st);
4332 }
4333 }
4334 st->cr();
4335 #if INCLUDE_ALL_GCS
4336 if (print_concurrent_locks) {
4337 concurrent_locks.print_locks_on(p, st);
4338 }
4339 #endif // INCLUDE_ALL_GCS
4340 }
4341
4342 VMThread::vm_thread()->print_on(st);
4343 st->cr();
4344 Universe::heap()->print_gc_threads_on(st);
4345 WatcherThread* wt = WatcherThread::watcher_thread();
4346 if (wt != NULL) {
4347 wt->print_on(st);
4348 st->cr();
4349 }
4350 CompileBroker::print_compiler_threads_on(st);
4351 st->flush();
4352 }
4353
4354 // Threads::print_on_error() is called by fatal error handler. It's possible
4355 // that VM is not at safepoint and/or current thread is inside signal handler.
4356 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4357 // memory (even in resource area), it might deadlock the error handler.
4358 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4359 bool found_current = false;
4360 st->print_cr("Java Threads: ( => current thread )");
4361 ALL_JAVA_THREADS(thread) {
4362 bool is_current = (current == thread);
4363 found_current = found_current || is_current;
4364
4365 st->print("%s", is_current ? "=>" : " ");
4366
4367 st->print(PTR_FORMAT, thread);
4368 st->print(" ");
4369 thread->print_on_error(st, buf, buflen);
4370 st->cr();
4371 }
4372 st->cr();
4373
4374 st->print_cr("Other Threads:");
4375 if (VMThread::vm_thread()) {
4376 bool is_current = (current == VMThread::vm_thread());
4377 found_current = found_current || is_current;
4378 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4379
4380 st->print(PTR_FORMAT, VMThread::vm_thread());
4381 st->print(" ");
4382 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4383 st->cr();
4384 }
4385 WatcherThread* wt = WatcherThread::watcher_thread();
4386 if (wt != NULL) {
4387 bool is_current = (current == wt);
4388 found_current = found_current || is_current;
4389 st->print("%s", is_current ? "=>" : " ");
4390
4391 st->print(PTR_FORMAT, wt);
4392 st->print(" ");
4393 wt->print_on_error(st, buf, buflen);
4394 st->cr();
4395 }
4396 if (!found_current) {
4397 st->cr();
4398 st->print("=>" PTR_FORMAT " (exited) ", current);
4399 current->print_on_error(st, buf, buflen);
4400 st->cr();
4401 }
4402 }
4403
4404 // Internal SpinLock and Mutex
4405 // Based on ParkEvent
4406
4407 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4408 //
4409 // We employ SpinLocks _only for low-contention, fixed-length
4410 // short-duration critical sections where we're concerned
4411 // about native mutex_t or HotSpot Mutex:: latency.
4412 // The mux construct provides a spin-then-block mutual exclusion
4413 // mechanism.
4414 //
4415 // Testing has shown that contention on the ListLock guarding gFreeList
4416 // is common. If we implement ListLock as a simple SpinLock it's common
4417 // for the JVM to devolve to yielding with little progress. This is true
4418 // despite the fact that the critical sections protected by ListLock are
4419 // extremely short.
4420 //
4421 // TODO-FIXME: ListLock should be of type SpinLock.
4422 // We should make this a 1st-class type, integrated into the lock
4423 // hierarchy as leaf-locks. Critically, the SpinLock structure
4424 // should have sufficient padding to avoid false-sharing and excessive
4425 // cache-coherency traffic.
4426
4427
4428 typedef volatile int SpinLockT ;
4429
4430 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4431 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4432 return ; // normal fast-path return
4433 }
4434
4435 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4436 TEVENT (SpinAcquire - ctx) ;
4437 int ctr = 0 ;
4438 int Yields = 0 ;
4439 for (;;) {
4440 while (*adr != 0) {
4441 ++ctr ;
4442 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4443 if (Yields > 5) {
4444 os::naked_short_sleep(1);
4445 } else {
4446 os::NakedYield() ;
4447 ++Yields ;
4448 }
4449 } else {
4450 SpinPause() ;
4451 }
4452 }
4453 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4454 }
4455 }
4456
4457 void Thread::SpinRelease (volatile int * adr) {
4458 assert (*adr != 0, "invariant") ;
4459 OrderAccess::fence() ; // guarantee at least release consistency.
4460 // Roach-motel semantics.
4461 // It's safe if subsequent LDs and STs float "up" into the critical section,
4462 // but prior LDs and STs within the critical section can't be allowed
4463 // to reorder or float past the ST that releases the lock.
4464 *adr = 0 ;
4465 }
4466
4467 // muxAcquire and muxRelease:
4468 //
4469 // * muxAcquire and muxRelease support a single-word lock-word construct.
4470 // The LSB of the word is set IFF the lock is held.
4471 // The remainder of the word points to the head of a singly-linked list
4472 // of threads blocked on the lock.
4473 //
4474 // * The current implementation of muxAcquire-muxRelease uses its own
4475 // dedicated Thread._MuxEvent instance. If we're interested in
4476 // minimizing the peak number of extant ParkEvent instances then
4477 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4478 // as certain invariants were satisfied. Specifically, care would need
4479 // to be taken with regards to consuming unpark() "permits".
4480 // A safe rule of thumb is that a thread would never call muxAcquire()
4481 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4482 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4483 // consume an unpark() permit intended for monitorenter, for instance.
4484 // One way around this would be to widen the restricted-range semaphore
4485 // implemented in park(). Another alternative would be to provide
4486 // multiple instances of the PlatformEvent() for each thread. One
4487 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4488 //
4489 // * Usage:
4490 // -- Only as leaf locks
4491 // -- for short-term locking only as muxAcquire does not perform
4492 // thread state transitions.
4493 //
4494 // Alternatives:
4495 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4496 // but with parking or spin-then-park instead of pure spinning.
4497 // * Use Taura-Oyama-Yonenzawa locks.
4498 // * It's possible to construct a 1-0 lock if we encode the lockword as
4499 // (List,LockByte). Acquire will CAS the full lockword while Release
4500 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4501 // acquiring threads use timers (ParkTimed) to detect and recover from
4502 // the stranding window. Thread/Node structures must be aligned on 256-byte
4503 // boundaries by using placement-new.
4504 // * Augment MCS with advisory back-link fields maintained with CAS().
4505 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4506 // The validity of the backlinks must be ratified before we trust the value.
4507 // If the backlinks are invalid the exiting thread must back-track through the
4508 // the forward links, which are always trustworthy.
4509 // * Add a successor indication. The LockWord is currently encoded as
4510 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4511 // to provide the usual futile-wakeup optimization.
4512 // See RTStt for details.
4513 // * Consider schedctl.sc_nopreempt to cover the critical section.
4514 //
4515
4516
4517 typedef volatile intptr_t MutexT ; // Mux Lock-word
4518 enum MuxBits { LOCKBIT = 1 } ;
4519
4520 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4521 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4522 if (w == 0) return ;
4523 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4524 return ;
4525 }
4526
4527 TEVENT (muxAcquire - Contention) ;
4528 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4529 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4530 for (;;) {
4531 int its = (os::is_MP() ? 100 : 0) + 1 ;
4532
4533 // Optional spin phase: spin-then-park strategy
4534 while (--its >= 0) {
4535 w = *Lock ;
4536 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4537 return ;
4538 }
4539 }
4540
4541 Self->reset() ;
4542 Self->OnList = intptr_t(Lock) ;
4543 // The following fence() isn't _strictly necessary as the subsequent
4544 // CAS() both serializes execution and ratifies the fetched *Lock value.
4545 OrderAccess::fence();
4546 for (;;) {
4547 w = *Lock ;
4548 if ((w & LOCKBIT) == 0) {
4549 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4550 Self->OnList = 0 ; // hygiene - allows stronger asserts
4551 return ;
4552 }
4553 continue ; // Interference -- *Lock changed -- Just retry
4554 }
4555 assert (w & LOCKBIT, "invariant") ;
4556 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4557 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4558 }
4559
4560 while (Self->OnList != 0) {
4561 Self->park() ;
4562 }
4563 }
4564 }
4565
4566 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4567 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4568 if (w == 0) return ;
4569 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4570 return ;
4571 }
4572
4573 TEVENT (muxAcquire - Contention) ;
4574 ParkEvent * ReleaseAfter = NULL ;
4575 if (ev == NULL) {
4576 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4577 }
4578 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4579 for (;;) {
4580 guarantee (ev->OnList == 0, "invariant") ;
4581 int its = (os::is_MP() ? 100 : 0) + 1 ;
4582
4583 // Optional spin phase: spin-then-park strategy
4584 while (--its >= 0) {
4585 w = *Lock ;
4586 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4587 if (ReleaseAfter != NULL) {
4588 ParkEvent::Release (ReleaseAfter) ;
4589 }
4590 return ;
4591 }
4592 }
4593
4594 ev->reset() ;
4595 ev->OnList = intptr_t(Lock) ;
4596 // The following fence() isn't _strictly necessary as the subsequent
4597 // CAS() both serializes execution and ratifies the fetched *Lock value.
4598 OrderAccess::fence();
4599 for (;;) {
4600 w = *Lock ;
4601 if ((w & LOCKBIT) == 0) {
4602 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4603 ev->OnList = 0 ;
4604 // We call ::Release while holding the outer lock, thus
4605 // artificially lengthening the critical section.
4606 // Consider deferring the ::Release() until the subsequent unlock(),
4607 // after we've dropped the outer lock.
4608 if (ReleaseAfter != NULL) {
4609 ParkEvent::Release (ReleaseAfter) ;
4610 }
4611 return ;
4612 }
4613 continue ; // Interference -- *Lock changed -- Just retry
4614 }
4615 assert (w & LOCKBIT, "invariant") ;
4616 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4617 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4618 }
4619
4620 while (ev->OnList != 0) {
4621 ev->park() ;
4622 }
4623 }
4624 }
4625
4626 // Release() must extract a successor from the list and then wake that thread.
4627 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4628 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4629 // Release() would :
4630 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4631 // (B) Extract a successor from the private list "in-hand"
4632 // (C) attempt to CAS() the residual back into *Lock over null.
4633 // If there were any newly arrived threads and the CAS() would fail.
4634 // In that case Release() would detach the RATs, re-merge the list in-hand
4635 // with the RATs and repeat as needed. Alternately, Release() might
4636 // detach and extract a successor, but then pass the residual list to the wakee.
4637 // The wakee would be responsible for reattaching and remerging before it
4638 // competed for the lock.
4639 //
4640 // Both "pop" and DMR are immune from ABA corruption -- there can be
4641 // multiple concurrent pushers, but only one popper or detacher.
4642 // This implementation pops from the head of the list. This is unfair,
4643 // but tends to provide excellent throughput as hot threads remain hot.
4644 // (We wake recently run threads first).
4645
4646 void Thread::muxRelease (volatile intptr_t * Lock) {
4647 for (;;) {
4648 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4649 assert (w & LOCKBIT, "invariant") ;
4650 if (w == LOCKBIT) return ;
4651 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4652 assert (List != NULL, "invariant") ;
4653 assert (List->OnList == intptr_t(Lock), "invariant") ;
4654 ParkEvent * nxt = List->ListNext ;
4655
4656 // The following CAS() releases the lock and pops the head element.
4657 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4658 continue ;
4659 }
4660 List->OnList = 0 ;
4661 OrderAccess::fence() ;
4662 List->unpark () ;
4663 return ;
4664 }
4665 }
4666
4667
4668 void Threads::verify() {
4669 ALL_JAVA_THREADS(p) {
4670 p->verify();
4671 }
4672 VMThread* thread = VMThread::vm_thread();
4673 if (thread != NULL) thread->verify();
4674 }